MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Cell Structure and Function' source. Tue, 07 Feb 2012 08:48:54 +0100 http://www.medworm.com/index.php?rid=5640284&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22277578%26dopt%3DAbstract In this study, we report the efficient generation of transgenic mouse lines expressing heritable and functional biosensors for ERK and PKA. These transgenic mice were created by the cytoplasmic co-injection of Tol2 transposase mRNA and a circular plasmid harbouring Tol2 recombination sites. High expression of the biosensors in a wide range of cell types allowed us to screen newborn mice simply by inspection. Observation of these transgenic mice by two-photon excitation microscopy yielded real-time activity maps of ERK and PKA in various tissues, with greatly improved signal-to-background ratios. Our transgenic mice may be bred into diverse genetic backgrounds; moreover, the protocol we have developed paves the way for the generation of transgenic mice that express other FRET biosensors, wi... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5640284 Tue, 24 Jan 2012 05:00:00 +0100 5640284 http://www.medworm.com/index.php?rid=5602327&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240728%26dopt%3DAbstract Authors: Drastichova Z, Novotny J Abstract Protein-protein interactions define specificity in signal transduction and these interactions are central to transmembrane signaling by G-protein-coupled receptors (GPCRs). It is not quite clear, however, whether GPCRs and the regulatory trimeric G-proteins behave as freely and independently diffusible molecules in the plasma membrane or whether they form some preassociated complexes. Here we used clear-native polyacrylamide gel electrophoresis (CN-PAGE) to investigate the presumed coupling between thyrotropin-releasing hormone (TRH) receptor and its cognate G(q/11) protein in HEK293 cells expressing high levels of these proteins. Under different solubilization conditions, the TRH receptor (TRH-R) was identified to form a putative pentamer... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5602327 Wed, 18 Jan 2012 13:48:02 +0100 5602327 http://www.medworm.com/index.php?rid=5535211&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185782%26dopt%3DAbstract Authors: Takashima K, Saitoh A, Hirose S, Nakai W, Kondo Y, Takasu Y, Kakeya H, Shin HW, Nakayama K Abstract Eukaryotic cells store neutral lipids and cholesteryl esters in cytoplasmic lipid droplets (LDs), which are generated from the endoplasmic reticulum (ER). Accumulating lines of evidence have indicated that Golgi-to-ER-retrograde transport mediated by COPI-coated vesicles under the control of Arf small GTPases is implicated in LD formation and utilization. However, the detailed mechanism underlying the regulation of lipid homeostasis by COPI-dependent transport has been poorly understood. Here we show that LD deposition and the cellular triacylglycerol content are significantly increased by siRNA-mediated depletion of not only β-COP (a subunit of the COPI coat complex) but a... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5535211 Sat, 24 Dec 2011 00:36:02 +0100 5535211 http://www.medworm.com/index.php?rid=5513772&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22139392%26dopt%3DAbstract Authors: Hayashi K, Suzuki A, Ohno S Abstract The serine/threonine kinase, PAR-1, is an essential component of the evolutionary-conserved polarity-regulating system, PAR-aPKC system, which plays indispensable roles in establishing asymmetric protein distributions and cell polarity in various biological contexts (Suzuki and Ohno, 2006; Matenia and Mandelkow, 2009). PAR-1 is also known as MARK, which phosphorylates classical microtubule-associated proteins (MAPs) and detaches MAPs from microtubules (Matenia and Mandelkow, 2009). This MARK activity of PAR-1 suggests its role in microtubule (MT) dynamics, but surprisingly, only few studies have been carried out to address this issue. Here, we summarize our recent study on live imaging analysis of MT dynamics in PAR-1b-depleted cells, w... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5513772 Sat, 03 Dec 2011 05:00:00 +0100 5513772 http://www.medworm.com/index.php?rid=5513773&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130451%26dopt%3DAbstract Authors: Ishijima S Abstract The change in the flagellar waves of spermatozoa from a tunicate and sea urchins was examined using high-speed video microscopy to clarify the regulation of localized sliding between doublet microtubules in the axoneme. When the tunicate Ciona spermatozoa attached to a coverslip surface by their heads in seawater or they moved in seawater with increased viscosity, the planar waves of the sperm flagella were converted into left-handed helical waves. On the other hand, conversion of the planar waves into helical waves in the sea urchin Hemicentrotus spermatozoa was not seen in seawater with an increased viscosity as well as in ordinary seawater. However, the sea urchin Clypeaster spermatozoa showed the conversion, albeit infrequently, when they thrust the... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5513773 Wed, 30 Nov 2011 05:00:00 +0100 5513773 http://www.medworm.com/index.php?rid=5513774&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22104080%26dopt%3DAbstract Authors: Masuda N, Shimodaira T, Shiu SJ, Tokai-Nishizumi N, Yamamoto T, Ohsugi M Abstract The precise control of spindle microtubule (MT) dynamics is essential for chromosome capture and alignment. Kif18A/kinesin-8, an essential regulator of kinetochore MT dynamics, accumulates at its plus-ends in metaphase but not prometaphase cells. The underlying mechanism of time-dependent and kinetochore MT-specific plus-end accumulation of Kif18A is unknown. Here, we examined the factors required for the MT plus-end accumulation of Kif18A. In Eg5 inhibitor-treated cells, Kif18A localized along the MTs in the monopolar spindle and rarely accumulated at their plus-ends, indicating that MT-kinetochore association was not sufficient to induce Kif18A accumulation. In contrast, taxol treatment tri... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5513774 Sat, 19 Nov 2011 05:00:00 +0100 5513774 http://www.medworm.com/index.php?rid=5421418&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22067999%26dopt%3DAbstract Authors: Ishikawa T, Taniguchi Y, Okada T, Takeda S, Mori K Abstract The accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates the unfolded protein response (UPR). The ER stress signal is sensed and transmitted by a transmembrane protein(s) in the ER. The number of these transducers has increased with evolution, one in yeast, three in worm and fly, and five in mammals. Here, we examined medaka fish, Oryzias latipes, as a vertebrate model organism, and found that the medaka genome encodes five UPR transducers. Analysis of a medaka embryonic cell line revealed that the mammalian UPR signaling mechanisms are very well conserved. Thus, XBP1 mRNA, which encodes the transcription factor XBP1 downstream of the IRE1 pathway, was spliced in response to ER stress, res... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5421418 Tue, 08 Nov 2011 05:00:00 +0100 5421418 http://www.medworm.com/index.php?rid=5380037&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22041111%26dopt%3DAbstract Authors: Saito K, Arai Y, Zhang J, Kobayashi K, Tani T, Nagai T Abstract Laser-scanning confocal microscopy has been employed for exploring structures at subcellular, cellular and tissue level in three dimensions. To acquire the confocal image, a coherent light source, such as laser, is generally required in conventional single-point scanning microscopy. The illuminating beam must be focused onto a small spot with diffraction-limited size, and this determines the spatial resolution of the microscopy system. In contrast, multipoint scanning confocal microscopy using a Nipkow disk enables the use of an incoherent light source. We previously demonstrated successful application of a 100 W mercury arc lamp as a light source for the Yokogawa confocal scanner unit in which a microlens arr... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5380037 Sat, 29 Oct 2011 04:00:00 +0100 5380037 http://www.medworm.com/index.php?rid=5297838&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21979235%26dopt%3DAbstract Authors: Takata Y, Kishine H, Sone T, Andoh T, Nozaki M, Poderycki M, Chesnut JD, Imamoto F Abstract Generation of iPS cells from mouse embryonic fibroblasts (MEF) was achieved using a BacMam transduction system containing a polycistronic plasmid expression vector for coincident and optimized expression of four defined reprogramming transcription factors. The sequences for Oct4, Klf4, Sox2 and c-Myc, were cloned as a fusion gene (OKSM) in a single open reading frame (ORF) via self-cleaving 2A peptides and expressed under the control of the CAG promoter. The transduction efficiency of primary MEF cells with BacMam particles carrying CAG-directed Venus reporter gene is 64-98 %. After three successive transductions (at intervals of 3 days) of MEF cells with BacMam particles carrying a... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5297838 Thu, 06 Oct 2011 04:00:00 +0100 5297838 http://www.medworm.com/index.php?rid=5297837&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21979236%26dopt%3DAbstract Authors: Lee SH, Kim IJ, Kim JG, Park JS, Kim YS, Yamaguchi M, Kim CM, Yoo MA Abstract Recent studies have suggested the involvement of epigenetic factors such as methyl-CpG-binding protein-2 (MeCP2) in tumorigenesis. In addition, cancer may represent a stem cell-based disease, suggesting that understanding of stem cell regulation could provide valuable insights into the mechanisms of tumorigenesis. However, the function of epigenetic factors in stem cell regulation in adult tissues remains poorly understood. In the present study, we investigated the role of human MeCP2 (hMeCP2), a bridge factor linked to DNA modification and histone modification, in stem cell proliferation using adult Drosophila midgut, which appears to be an excellent model system to study stem cell biology. Resu... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5297837 Thu, 06 Oct 2011 04:00:00 +0100 5297837 http://www.medworm.com/index.php?rid=5157450&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21857145%26dopt%3DAbstract Authors: Ninagawa S, Okada T, Takeda S, Mori K Abstract Proteins misfolded in the endoplasmic reticulum (ER) are degraded in the cytosol by a ubiquitin-dependent proteasome system, a process collectively termed ER-associated degradation (ERAD). Unraveling the molecular mechanisms of mammalian ERAD progresses more slowly than that of yeast ERAD due to the laborious procedures required for gene targeting and the redundancy of components. Here, we utilized the chicken B lymphocyte-derived DT40 cell line, which exhibits an extremely high homologous recombination frequency, to analyze ERAD mechanisms in higher eukaryotes. We disrupted the SEL1L gene, which encodes the sole homologue of yeast Hrd3p in both chickens and mammals; Hrd3p is a binding partner of yeast Hrd1p, an E3 ubiquitin l... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5157450 Fri, 19 Aug 2011 23:00:00 +0100 5157450 http://www.medworm.com/index.php?rid=5058027&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21757827%26dopt%3DAbstract Authors: Tanimoto K, Suzuki K, Jokitalo E, Sakai N, Sakaguchi T, Tamura D, Fujii G, Aoki K, Takada S, Ishida R, Tanabe M, Itoh H, Yoneda Y, Sohda M, Misumi Y, Nakamura N The Yip1 domain family (YIPF) proteins are homologues of yeast Yip1p and Yif1p, which are proposed to function in ER to Golgi transport. Here, we report the characterization of YIPF3 and YIPF4, homologues of human Yif1p and Yip1p, respectively. Immunofluorescence and immuno-electron microscopy showed that both YIPF3 and YIPF4 are clearly concentrated in the cis-Golgi. While YIPF4 was detected as a single mobility form consistent with its predicted molecular weight, three different mobility forms of YIPF3 were detected by western blotting. Biochemical and immunofluorescence experiments strongly indicated that YIPF3 is s... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5058027 Wed, 13 Jul 2011 23:00:00 +0100 5058027 http://www.medworm.com/index.php?rid=5058028&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21737958%26dopt%3DAbstract Authors: Fukuda M, Kobayashi H, Ishibashi K, Ohbayashi N The RUN domain is a less conserved protein motif that consists of approximately 70 amino acids, and because RUN domains are often found in proteins involved in the regulation of Rab small GTPases, the RUN domain has been suggested to be involved in Rab-mediated membrane trafficking, possibly as a Rab-binding site. However, since the Rab binding activity of most RUN domains has never been investigated, in this study we performed a genome-wide analysis of the Rab binding activity of the RUN domains of 19 different RUN domain-containing proteins by yeast two-hybrid assays with 60 different Rabs as bait. The results showed that only six of them interact with specific Rab isoforms with different Rab binding specificity, i.e., DENND5A/... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=5058028 Wed, 06 Jul 2011 23:00:00 +0100 5058028 http://www.medworm.com/index.php?rid=4961684&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21685705%26dopt%3DAbstract Authors: Ozono K, Komiya S, Shimamura K, Ito T, Nagafuchi A To define the roles of α-catenin in cell-cell adhesion, the E-cadherin, α-catenin, β-catenin, and/or plakoglobin genes were inactivated in F9 teratocarcinoma cells. An E-cadherin-α-catenin fusion protein (Eα) restored full cell-adhesion function and organized the actin-based cytoskeleton and ZO-1, an actin filament binding protein, in F9 cells lacking all endogenous cadherin-catenin complex components. There were two types of cadherin-based cell-adhesion junctions in parental F9 cells, those with ZO-1 and those without ZO-1, and only junctions with ZO-1 were associated with thick actin bundles. Additionally, ZO-1 localized to most Eα-based cell-adhesion junctions. These data demonstrated that Eα supported cadherin-based... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4961684 Fri, 24 Jun 2011 11:30:02 +0100 4961684 http://www.medworm.com/index.php?rid=4813715&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21512259%26dopt%3DAbstract Authors: Kato Y, Ushijima Y, Yamaguchi M G9a is one of the well-characterized histone methyltransferases. G9a regulates H3K9 mono- and dimethylation at euchromatic region and consequently plays important roles in euchromatic gene regulation. Mammalian G9a contains several distinct domains, such as GHD (G9a homology domain), ANK, preSET, SET and PostSET. These domains are highly conserved between mammals and Drosophila. Although mammalian G9a has nuclear localization signal (NLS) in its N-terminal region, the amino acid sequences of this region are not conserved in Drosophila. Here we have examined the subcellular localization of a series of truncated forms of Drosophila G9a (dG9a). The identified region (aa337-aa470) responsible for nuclear localization of dG9a contains four short stre... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4813715 Thu, 21 Apr 2011 23:00:00 +0100 4813715 http://www.medworm.com/index.php?rid=4705933&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21478632%26dopt%3DAbstract Authors: Kawamori A, Yamaguchi M DREF (DNA replication-related element-binding factor) plays important roles in replication and proliferation in vivo by regulating transcription of various genes. However, due to a lack of appropriate cell biological studies in vivo, roles of DREF during a single cell development are poorly understood. To address this question, we focused our attention on macrochaetes bristle development system. Utilizing cell lineage analysis focusing on a single posterior scutellar (PSC) macrochaete sensory organ precursor (SOP) lineages in combination with GAL4/UAS targeted expression system for DREF double strand RNA, we revealed that DREF plays no apparent role in differentiation process during SOP formation. Rather, DREF regulates the timing of asymmetric cell div... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4705933 Fri, 08 Apr 2011 23:00:00 +0100 4705933 http://www.medworm.com/index.php?rid=4705962&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21467691%26dopt%3DAbstract Authors: Horikoshi Y, Hamada S, Ohno S, Suetsugu S Electrostatic interactions between lipids and proteins control many cellular events. We found that phospholipids, including phosphatidylinositol 3-phosphate, phosphatidylinositol 4,5-bisphosphate, and phosphatidylinositol 3,4,5-triphosphate, bound to the C-terminal coiled-coil region of par-3 at conserved, basic residues. We identified K1013 and K1014 as the phosphoinositide binding site, because the K1013E/K1014E mutation of rat par-3 abolished its lipid binding. Importantly, the K1013E/K1014E par-3 mutant exhibited significantly weaker localization at the cell-cell junctions than the wild-type par-3. Fluorescence recovery after photo-bleaching analyses confirmed the faster turnover of mutant par-3 at cell-cell junctions. The treatmen... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4705962 Fri, 01 Apr 2011 23:00:00 +0100 4705962 http://www.medworm.com/index.php?rid=4582627&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21368446%26dopt%3DAbstract Authors: Funaki T, Kon S, Ronn RE, Henmi Y, Kobayashi Y, Watanabe T, Nakayama K, Tanabe K, Satake M SMAP2 is an Arf GTPase-activating protein that is located and functions on early endosome membranes. In the present study, the trans-Golgi network (TGN) was verified as an additional site of SMAP2 localization based on its co-localization with various TGN-marker proteins. Mutation of specific stretches of basic amino acid residues abolished the TGN-localization of SMAP2. Over-expression of wild-type SMAP2, but not of the mutated SMAP2, inhibited the transport of vesicular stomatitis virus-G protein from the TGN to the plasma membrane. In contrast, this transport was enhanced in SMAP2 (-/-) cells characterized by increased levels of the activated form of Arf. SMAP2 therefore belongs to an... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4582627 Sat, 26 Feb 2011 00:00:00 +0100 4582627 http://www.medworm.com/index.php?rid=4582628&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21358125%26dopt%3DAbstract Authors: Kambara Y, Shiba K, Yoshida M, Sato C, Kitajima K, Shingyoji C Flagellar movement of the sea urchin sperm is regulated by intracellular Ca(2+). Flagellasialin, a polysialic acid-containing glycoprotein, as well as other membrane proteins seems responsible for the Ca(2+) control. To elucidate the mechanism of Ca(2+) dynamics underlying flagellar movement, we analysed the sperm's mechanosensory behavioural responses by using microtechniques. In sea water containing 10 mM Ca(2+), the sperm swim in circular paths. When a mechanical stimulus was applied to the sperm head with a glass microstylus, the sperm showed a series of flagellar responses, consisting of a stoppage of beating (quiescence) and a recovery of swimming in a straight path, followed by swimming in a circular path ag... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4582628 Fri, 25 Feb 2011 00:00:00 +0100 4582628 http://www.medworm.com/index.php?rid=4530423&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21317539%26dopt%3DAbstract Authors: Montanaro L, Govoni M, Orrico C, Treré D, Derenzini M The precise location of rDNA transcription to the components of mammalian cell nucleolus is still debated. This was due to the fact that all the molecules necessary for rRNA synthesis are located in two of the three components, the fibrillar centers (FCs) and the dense fibrillar component (DFC), which together with the granular component (GC) are considered to be constantly present in mammalian cell nucleoli. In the present study we demonstrated that in nucleoli of many regenerating rat hepatocytes at 15 h after partial hepatectomy the FCs were no longer present, only the DFC and the GC being detected. At this time of regeneration the rRNA transcriptional activity was three fold that of resting hepatocytes, while the synth... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4530423 Wed, 09 Feb 2011 00:00:00 +0100 4530423 http://www.medworm.com/index.php?rid=4474561&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21307607%26dopt%3DAbstract Authors: Fukumoto M, Sekimoto T, Yoneda Y Many transport factors, such as importins and exportins, have been identified, and the molecular mechanisms underlying nucleocytoplasmic transport have been characterized. The specific molecules that are carried by each transport factor and the temporal profiles that characterize the movements of various proteins into or out of the nucleus, however, have yet to be elucidated. Here, we used a proteomic approach to identify molecules that are transported into the nuclei of adult mouse brain cells via importin α5. We identified 48 proteins in total, among which we chose seven to characterize more extensively: acidic (leucine-rich) nuclear phosphoprotein 32 family member A (Anp32a), far upstream element binding protein 1 (FUBP1), thyroid hormone r... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4474561 Sat, 05 Feb 2011 00:00:00 +0100 4474561 http://www.medworm.com/index.php?rid=4411784&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21263197%26dopt%3DAbstract Authors: Ito M, Kitamura H, Kikuguchi C, Hase K, Ohno H, Ohara O We investigated the effects of SP600125 (formerly called c-Jun N-terminal kinase (JNK) inhibitor II) on translation using cultured mouse cells. SP600125 (50 µM) treatment rapidly repressed overall protein synthesis, accompanied by a reduction in the mRNAs for housekeeping genes such as glyceraldehyde-3-phosphate dehydrogenase in the polysomal fraction. SP600125 decreased polysomes with a concomitant increase in free ribosomal subunits in the cytoplasm, suggesting that global translation was inhibited at the initiation step. A reporter analysis using exogenous mRNAs showed that SP600125 inhibited cap-dependent but not internal ribosome entry site-dependent translation. SP600125 significantly attenuated phosphorylation of ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4411784 Thu, 20 Jan 2011 00:00:00 +0100 4411784 http://www.medworm.com/index.php?rid=4411786&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21258165%26dopt%3DAbstract In this study, we examined the effects of four amide derivatives of DIF-1 on stalk cell differentiation and chemotaxis. The DIF derivatives differentially affected cell differentiation and chemotaxis, suggesting the possible existence of at least three receptors for DIFs: one receptor responsible for stalk cell induction, and two receptors responsible for chemotaxis modulation. Furthermore, our results indicate that DIF derivatives can be utilized to analyze the DIF-signaling pathways. PMID: 21258165 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4411786 Wed, 19 Jan 2011 00:00:00 +0100 4411786 http://www.medworm.com/index.php?rid=4344008&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21206131%26dopt%3DAbstract Conclusions: This study implies that repopulation is not a temporary reaction to irradiation. It is caused probably by "clonal" gene-expression changes, though it remains unknown whether the changes are attributable to tolerant cell selection or to gene mutation/modification. PMID: 21206131 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4344008 Sat, 25 Dec 2010 00:00:00 +0100 4344008 http://www.medworm.com/index.php?rid=4279035&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21150128%26dopt%3DAbstract Authors: Oku M, Tanakura S, Uemura A, Sohda M, Misumi Y, Taniguchi M, Wakabayashi S, Yoshida H When increased production of secretory proteins overwhelms the capacity of the endoplasmic reticulum (ER) and the Golgi apparatus, eukaryotic cells expand their capacity to sustain secretory function. The capacity of the ER is enhanced by the mechanism called the ER stress response, but the mechanism regulating Golgi capacity (the Golgi stress response) has remained unclear. Here, we found that transcription of Golgi-related genes, including glycosylation enzymes as well as factors involved in post-Golgi vesicular transport and maintenance of Golgi structure, was upregulated upon treatment with monensin, an ionophore that disrupts the function of acidic organelles, including the Golgi apparat... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4279035 Wed, 08 Dec 2010 00:00:00 +0100 4279035 http://www.medworm.com/index.php?rid=4279034&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21150129%26dopt%3DAbstract Authors: Yamamoto YH, Kimura T, Momohara S, Takeuchi M, Tani T, Kimata Y, Kadokura H, Kohno K Cytosolic Hsc70/Hsp70 are known to contribute to the endoplasmic reticulum (ER)-associated degradation of membrane proteins. However, at least in mammalian cells, its partner ER-localized J-protein for this cellular event has not been identified. Here we propose that this missing protein is DNAJB12. Protease protection assay and immunofluorescence study revealed that DNAJB12 is an ER-localized single membrane-spanning protein carrying a J-domain facing the cytosol. Using co-immunoprecipitation assay, we found that DNAJB12 is able to bind Hsc70 and thus can recruit Hsc70 to the ER membrane. Remarkably, cellular overexpression of DNAJB12 accelerated the degradation of misfolded membrane proteins... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4279034 Wed, 08 Dec 2010 00:00:00 +0100 4279034 http://www.medworm.com/index.php?rid=4279033&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21150130%26dopt%3DAbstract Authors: Sato Y, Nadanaka S, Okada T, Okawa K, Mori K The transcription factor ATF6 is constitutively synthesized as a type II transmembrane protein embedded in the endoplasmic reticulum (ER). When unfolded proteins accumulate in the ER, ATF6 senses such ER stress via an as yet undetermined mechanism and relocates to the Golgi apparatus where it is cleaved by sequential action of Site-1 and Site-2 proteases, allowing liberated N-terminal fragments to translocate into the nucleus. This ATF6-mediated transcriptional induction of ER-localized molecular chaperones and folding enzymes together with components of ER-associated degradation leads to the maintenance of ER homeostasis in mammals. Here, we demonstrated that the luminal domain of ATF6 alone is sufficient for sensing ER stress and ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4279033 Wed, 08 Dec 2010 00:00:00 +0100 4279033 http://www.medworm.com/index.php?rid=4279032&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21150131%26dopt%3DAbstract Authors: Ishida N, Nakamura Y, Tanabe K, Li SA, Takei K Dynamin, a ~100 kDa large GTPase, is known as a key player for membrane traffic. Recent evidence shows that dynamin also regulates dynamic instability of microtubules by a mechanism independent of membrane traffic. As microtubules are highly dynamic during mitosis, we investigated whether the regulation of microtubules by dynamin is essential for cell cycle progression. Dynamin 2 intensely localized at the mitotic spindle, and the localization depended on its proline-rich domain (PRD), which is required for microtubule association. The deletion of PRD resulted in the impairment of cytokinesis, whereas the mutant had less effect on endocytosis. Interestingly, dominant-negative dynamin (K44A), which blocks membrane traffic but has n... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4279032 Wed, 08 Dec 2010 00:00:00 +0100 4279032 http://www.medworm.com/index.php?rid=4088893&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20953064%26dopt%3DAbstract Authors: Mauchi N, Ohtake Y, Irie K Khd1p (KH-domain protein 1) is a yeast RNA-binding protein highly homologous to mammalian hnRNP K. Khd1p associates with hundreds of potential mRNA targets including a bud-localized ASH1 mRNA and mRNAs encoding membrane-associated proteins such as Mid2p and Mtl1p. While Khd1p negatively regulates gene expression of Ash1p by translational repression, Khd1p positively regulates gene expression of Mtl1p by mRNA stabilization. To investigate how Khd1p regulates the stability of MTL1 mRNA, we searched for cis-acting elements and trans-acting factors controlling MTL1 mRNA stability. Regional analysis revealed that partial deletion of the coding sequences of MTL1 mRNA restored the decreased MTL1 mRNA and protein levels in khd1Δ mutants. This region, encomp... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4088893 Tue, 12 Oct 2010 23:00:00 +0100 4088893 http://www.medworm.com/index.php?rid=4000139&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20859058%26dopt%3DAbstract Authors: Ozaki C, Yoshioka M, Tominaga S, Osaka Y, Obata S, T Suzuki S The role of p120-catenin in the function of classical cadherins is still enigmatic despite various studies. To elucidate its role, we examined the effect of p120-catenin on the N-cadherin-mediated localization of junctional proteins in epithelial cells in this study. Cadherin-deficient MIA PaCa-2 epithelial cells did not show linear localization of tight junction proteins ZO-1 and occludin. When N-cadherin was expressed in these cells, however, the resultant transfectant cells revealed strong cell adhesion activity and linear localization of ZO-1, occludin, and N-cadherin in the lateral membrane. When the p120-catenin-binding site of N-cadherin was disrupted, the linear localization of ZO-1 and occludin disappeared,... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=4000139 Wed, 15 Sep 2010 23:00:00 +0100 4000139 http://www.medworm.com/index.php?rid=3692032&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20562497%26dopt%3DAbstract Authors: Okuda S, Higashiyama T Sexual reproduction in flowering plants requires pollen-tube guidance, which is thought to be mediated by chemoattractants derived from target ovules. To date, however, no convincing evidence has been reported of a particular molecule being the true attractant. Emerging data indicate that two synergid cells, which are on either side of the egg cell, emit a diffusible, species-specific signal to attract the pollen tube at the last step of pollen-tube guidance. Recently, it was demonstrated that LUREs (LURE1 and LURE2), cysteine-rich polypeptides secreted from the synergid cell, are the key molecules in pollen-tube guidance. In this review, we summarize the mechanism of pollen-tube guidance, with special focus on gametophytic guidance and the attractants. ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3692032 Fri, 25 Jun 2010 03:03:02 +0100 3692032 http://www.medworm.com/index.php?rid=3645411&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20526042%26dopt%3DAbstract Authors: Shiraki N, Harada S, Ogaki S, Kume K, Kume S Although there are several markers available for the identification of endoderm derivatives such as the lung, pancreas, liver, and intestine, there are still very few surface markers available for the prospective isolation of the definitive endoderm. Among these, CXCR4 has been used in combination with E-cadherin as a cell surface marker to identify the definitive endoderm. However, CXCR4 expression decreases in late gut epithelium. Here we report a gene, Decay Accelerating Factor (DAF1/CD55), as a candidate surface marker for the identification of the early and late definitive endoderm. Daf1 is expressed in the definitive endoderm and mesoderm in early embryo at E8.5. Flow cytometry analysis of ES cells-derived differentiated cells... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3645411 Thu, 03 Jun 2010 23:00:00 +0100 3645411 http://www.medworm.com/index.php?rid=3564634&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20460816%26dopt%3DAbstract We report in this study that pretreatment with trypsin greatly enhanced siRNA delivery into quiescent reserve cells, resulting in efficient silencing of Grb2 expression. By applying combination of Grb2-silencing and protein kinase C inhibitors, we demonstrated that extracellular signal-regulated kinase (ERK) phosphorylation induced with fibroblast growth factor 2 (FGF2) was dependent on both Grb2 and protein kinase C (PKC) with different kinetics. We conclude that PKC-mediated pathway contributes to rapid initiation and termination of ERK phosphorylation while Grb2-mediated pathway contributes delayed and sustained ERK phosphorylation. PMID: 20460816 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3564634 Fri, 30 Apr 2010 23:00:00 +0100 3564634 http://www.medworm.com/index.php?rid=3546081&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20448405%26dopt%3DAbstract In this study, we examined the role of EGF receptor (EGFR) signaling in osteoblastogenesis in vitro. The expression of HB-EGF and epiregulin (EPR) was transiently induced within 24 h after osteogenic stimulation, but when preosteoblastic MC3T3-E1 cells were incubated with HB-EGF or EPR, osteoblast differentiation was inhibited. These effects were Ras-dependent, and ERK modulated Runx2 activity through the localization of Smad1 and the induction of Twist2. PI3-kinase was also required for the induction of Twist2. However, the inhibition of individual signaling pathways was not sufficient to overcome HB-EGF-mediated inhibition of osteoblast differentiation. Additionally, HB-EGF treatment promoted the proliferation of preosteoblasts, and this was associated with the downregulation of p27 at t... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3546081 Fri, 23 Apr 2010 23:00:00 +0100 3546081 http://www.medworm.com/index.php?rid=3515895&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20424340%26dopt%3DAbstract Authors: Horáková AH, Bártová E, Kozubek S Here, we would like to point out important milestones in the study of nuclear radial positioning and gene expression during differentiation processes. In addition, changes in the histone signature that significantly preceed various differentiation pathways are reviewed. We address the regulatory functions of chromatin structure and histone epigenetic marks that give rise to gene expression patterns that are specific to distinct differentiation pathways. The functional relevance of nuclear architecture and epigenetic traits is preferentially discussed in the context of in vitro induced enterocytic differentiation and pluripotent or differentiated embryonic stem cells. We especially focus on the recapitulation of nuclear events that ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3515895 Wed, 14 Apr 2010 23:00:00 +0100 3515895 http://www.medworm.com/index.php?rid=3355117&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20215702%26dopt%3DAbstract Authors: Ikeda T Nucleoside diphosphate (NDP) kinase is an enzyme that synthesizes the nucleoside triphosphates. In mammals, nine sequences (NDK1-NDK9) have been found with domain(s) homologous to the catalytic domain of NDP kinase, and some of their products have been shown to associate with sperm flagella. The present study examines the localization of NDK7, for which little information has been available. Database analysis showed that the NDK7 gene is present in organisms with cilia and flagella. Western blotting analyses of various mouse tissues consistently indicated that NDK7 is preferentially expressed in tissues with motile cilia as well as in sperm. Immunofluorescence microscopy revealed that this protein is localized along the entire length of the TritonX-100-insoluble fracti... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3355117 Wed, 10 Mar 2010 00:00:00 +0100 3355117 http://www.medworm.com/index.php?rid=3322770&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20190463%26dopt%3DAbstract Authors: Ichise T, Adachi S, Ohishi M, Ikawa M, Okabe M, Iwamoto R, Mekada E Tumor progression is a complex process that involves the interaction of cancer cells with the cancer-surrounding stromal cells. The cancer stroma influences the cancer cell growth and metastatic potential. The EGF family growth factor HB-EGF is synthesized in cancer cells and plays pivotal roles in oncogenic transformation and tumor progression, but the contribution of HB-EGF expressed in tumor stromal cells to tumor growth remains unclear. In the present study, we found that HB-EGF was expressed in host-derived cancer stromal cells in xenograft and allograft mouse tumor models. CRM197 is a specific inhibitor of human HB-EGF that has no effect on mouse HB-EGF. To elucidate whether host-derived stromal HB-EGF c... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3322770 Tue, 02 Mar 2010 21:38:02 +0100 3322770 http://www.medworm.com/index.php?rid=3322771&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20190462%26dopt%3DAbstract Authors: Ikegami K, Setou M Microtubule (MT) plays specialized roles in a wide variety of cellular events, e.g. molecular transport, cell motility, and cell division. Specialized MT architectures, such as bundles, axonemes, and centrioles, underlie the function. The specialized function and highly organized structure depend on interactions with MT-binding proteins. MT-associated proteins (e.g. MAP1, MAP2, and tau), molecular motors (kinesin and dynein), plus-end tracking proteins (e.g. CLIP-170), and MT-severing proteins (e.g. katanin) interact with MTs. How can the MT-binding proteins know temporospatial information to associate with MTs and to properly play their roles? Post-translational modifications (PTMs) including detyrosination, polyglutamylation, and polyglycylation can provid... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3322771 Sat, 27 Feb 2010 00:00:00 +0100 3322771 http://www.medworm.com/index.php?rid=3195935&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20086311%26dopt%3DAbstract This article has been retracted at the request of the Editor-in-Chief of the Cell Structure and Function. This review article contains a substantial amount of text that had previously appeared in other published articles, including the Elsevier journals Current Biology (Howell et al., Curr. Biol. 2004 Jun 8; 14(11): 953-964), Trends in Cell Biology (Karess, Trends Cell Biol. 2005 Jul; 15(7): 386-392) and Current Opinion in Cell Biology (Yu, Curr. Opin. Cell Biol. 2002 Dec; 14(6): 706-714). In accordance with policies and procedures governing academic publication we concluded that the above-mentioned article published in Cell Struct. Funct. be retracted. We apologize to readers of the journals that this was not detected during the submission and review process. PMID: 20086311 [PubMed - ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=3195935 Fri, 22 Jan 2010 15:08:03 +0100 3195935 http://www.medworm.com/index.php?rid=2948586&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19875898%26dopt%3DAbstract Authors: Ohtani M, Mizuno I, Kojima Y, Ishikawa Y, Sodeno M, Asakura Y, Samejima K, Oka T In order to assess the functional role of the polyamines spermidine and spermine in pancreatic beta-cells, we examined the effect of spermidine and spermine synthase inhibitors, trans-4-methylcyclohexylamine (MCHA) and N-(3-aminopropyl)cyclohexylamine (APCHA), on cellular polyamine and insulin contents, insulin secretion, and cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) in mouse insulin-secreting Beta-TC6 cells. The cellular spermidine and spermine contents were reduced 90% and 64% by cultivation of cells in the presence of MCHA and APCHA for 3 days, respectively. Addition of spermidine or spermine reversed the polyamine level reduced by MCHA or APCHA, respectively. Insulin secretion was decreas... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2948586 Mon, 02 Nov 2009 00:58:03 +0100 2948586 http://www.medworm.com/index.php?rid=2782718&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19738360%26dopt%3DAbstract Authors: Okayama M, Arakawa T, Tanimura A, Mizoguchi I, Tajima Y, Takuma T To evaluate the role of VAMP8/endobrevin in constitutive exocytosis, we have examined the exocytotic pathways of VAMP8 and human growth hormone, both GFP-tagged, by total internal reflection fluorescence microscopy (TIRF-M). Human GH-GFP and VAMP8-GFP were similarly expressed in small round vesicles and elongated tubular vesicles in HeLa cells, and were mostly exocytosed at the peripheral area of the cells. VAMP8-GFP gave 2 types of exocytotic images: a burst type and a non-burst type. The burst type showed a sharp transient increase in the peak fluorescence intensity and a much slower decrease in the average intensity in the active windows, where exocytosis took place, as observed in the full-fusion type of exo... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2782718 Mon, 07 Sep 2009 23:00:00 +0100 2782718 http://www.medworm.com/index.php?rid=2762348&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19724156%26dopt%3DAbstract In this report, we identify molecules responsible for the malignant properties of tumor cells that survive irradiation. These molecules may be important therapeutic targets for the control of repopulated tumors after radiotherapy. PMID: 19724156 [PubMed - in process] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2762348 Thu, 03 Sep 2009 21:52:03 +0100 2762348 http://www.medworm.com/index.php?rid=2675476&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19652424%26dopt%3DAbstract This report characterizes expression of the three prolyl 3-hydroxylase genes in embryonic and adult mice. Overall these data demonstrate tissue specific prolyl 3-hydroxylase gene expression in both fetal and adult tissues indicating a developmental role for prolyl 3-hydroxylase activity. PMID: 19652424 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2675476 Fri, 31 Jul 2009 23:00:00 +0100 2675476 http://www.medworm.com/index.php?rid=2630428&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19622873%26dopt%3DAbstract Authors: Kikkawa N, Ohno T, Nagata Y, Shiozuka M, Kogure T, Matsuda R Ectopic calcification occurs in the skeletal muscle of mdx mice, a dystrophin-deficient animal model of Duchenne muscular dystrophy. The purpose of this study was to clarify the mechanism of the calcification. The calcified deposits were identified as hydroxyapatite, a crystallized form of calcium phosphate, and the serum inorganic phosphate (Pi) level in the mdx mice was approximately 1.4 times higher than that in the normal B10 mice, suggesting that Pi plays a critical role in the ectopic calcification. When C2C12 mouse myoblasts were cultured under high-Pi conditions, myogenic differentiation was retarded while the expression of osteogenic markers such as osteocalcin and Runx2 were upregulated. This was followed b... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2630428 Fri, 17 Jul 2009 23:00:00 +0100 2630428 http://www.medworm.com/index.php?rid=2526265&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19384053%26dopt%3DAbstract We examined whether insulin signaling extrinsically induces the greatest cell growth in Drosophila diploid cells and found that spermatocyte growth was affected in mutants. The results indicate that in addition to its function in somatic cells, insulin signaling plays an essential role in cell proliferation and growth during male Drosophila gametogenesis and that sperm production is regulated by hormonal control via insulin-like peptides. PMID: 19384053 [PubMed - in process] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2526265 Sat, 27 Jun 2009 11:31:04 +0100 2526265 http://www.medworm.com/index.php?rid=2526262&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19420794%26dopt%3DAbstract Authors: Lu Y, Wang Z, Ge L, Chen N, Liu H The conserved protein Rod is found in various organisms. It is localized on the kinetochores or spindle microtubules during cell division. Rod is required for proper chromosome segregation during both mitosis and meiosis. The effects of rod mutations are similar for both equational and reductional divisions, giving rise to anaphases with lagging chromosomes and/or unequal numbers of chromosomes at the two poles. Recent studies have shown that Rod is a significant component of the mitotic checkpoint. It can form the RZZ complex with Zw10 and Zwilch, which plays an important role in maintaining a functional spindle assembly checkpoint. PMID: 19420794 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2526262 Sat, 27 Jun 2009 11:31:04 +0100 2526262 http://www.medworm.com/index.php?rid=2526260&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19521025%26dopt%3DAbstract Authors: Okamoto K, Shinkai Y Telomere is the nucleoprotein complex essential for genomic integrity of linear chromosomes. Six telomere localizing proteins form a complex named "shelterin/telosome" to cooperatively regulate telomere length and protect chromosomal ends from DNA damage and repair responses. Mouse embryonic stem (ES) cells lacking TRF1, a shelterin component, exhibit a high-incidence of broken or lost telomere FISH signals, supporting a critical role for TRF1 in telomere maintenance. We demonstrate that these abnormal telomere structures are not caused by the inability of TRF1-deficient cells to recruit TIN2 but are due to a specific role for TRF1 at telomeres. Furthermore, we provide evidences that the mTRF1 TRF homology (TRFH) domain is crucial for this abnormal telomer... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2526260 Wed, 10 Jun 2009 23:00:00 +0100 2526260 http://www.medworm.com/index.php?rid=2301020&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19305101%26dopt%3DAbstract Authors: Nishiumi F, Sone T, Kishine H, Thyagarajan B, Kogure T, Miyawaki A, Chesnut JD, Imamoto F An important consideration in the design of multigene delivery technology is the availability of suitable vectors to introduce multiple genes stably and stoichiometrically into living cells and co-express these genes efficiently. As a promising system for this purpose, we developed multi-cDNA expression constructs harboring two to three tandemly situated cDNAs in a single plasmid. The utility of this vector system is amplified by combining it with the psiC31 recombinase system which mediates site-specific integration of the genes into naturally occurring chromosomal sequences. By analyzing 55 psiC31-mediated integration events with five different constructs, each carrying one, two or thre... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2301020 Fri, 20 Mar 2009 04:00:00 +0100 2301020 http://www.medworm.com/index.php?rid=2275196&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19293534%26dopt%3DAbstract In this study, we prepared a novel monoclonal antibody against human PCLP1 (hPCLP1) and attempted to isolate human hematopoietic progenitor cells from umbilical cord blood and peripheral blood using nano-sized bacterial magnetic particles (BacMPs) coupled with the anti-hPCLP1 antibody. Flow cytometric analysis demonstrated that the purity of separated hPCLP1-positive cells from peripheral blood was approximately 95% whereas peripheral blood mononuclear cells contained only 0.1% PCLP1(+) cells. Umbilical cord blood was demonstrated to be a better source for PCLP1(+) cells than peripheral blood. These results suggest that the separation of human PCLP1(+) cells using BacMPs with anti-hPCLP1 were extremely effective and may be useful as a means to prepare human hematopoietic progenitor cells. ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2275196 Tue, 17 Mar 2009 04:00:00 +0100 2275196 http://www.medworm.com/index.php?rid=2275195&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19293535%26dopt%3DAbstract Conclusions: It seems likely that ATF5 is a potent repressor of p53 and elevated expression of ATF5 in a tumor may relate to enhanced malignant phenotypes, such as radioresistance or greater cell motility. PMID: 19293535 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2275195 Tue, 17 Mar 2009 04:00:00 +0100 2275195 http://www.medworm.com/index.php?rid=2192363&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19218742%26dopt%3DAbstract In this study we irradiated muscle fibers isolated from skeletal muscle of SJL/J mice with heavy-ion microbeam, and the ultrastructural changes were observed by electron microscopy. The plasma membrane of heavy-ion beam irradiated areas showed irregular protrusions and invaginations. Disruption of sarcomeric structures and the enhancement of autophagy were also observed. In addition, many vesicles of varying size and shape were seen to be accumulated just beneath the plasma membrane. This finding further supports the recent hypothesis that dysferlin functions as a membrane fusion protein in the wound healing system of plasma membrane, and that the defect in dysferlin causes insufficient membrane fusion resulting in accumulation of vesicles. PMID: 19218742 [PubMed - as supplied by publi... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2192363 Fri, 13 Feb 2009 05:00:00 +0100 2192363 http://www.medworm.com/index.php?rid=2081762&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19122331%26dopt%3DAbstract In this study, we show that pXBP1(U) targets the active form of ATF6 but not ATF4 for destruction by the proteasome via direct association. This enhanced degradation is mediated by the degradation domain located at the pXBP1(U)-specific C-terminal end. We conclude that pXBP1(U) functions as a negative regulator of the UPR-specific transcription factors ATF6 and pXBP1(S). PMID: 19122331 [PubMed - as supplied by publisher] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2081762 Thu, 01 Jan 2009 05:00:00 +0100 2081762 http://www.medworm.com/index.php?rid=2048701&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19088398%26dopt%3DAbstract Authors: Oki Y, Watanabe S, Endo T, Kano K We investigated whether de-differentiated fat (DFAT) cells, a mature adipocyte-derived preadipocyte cell line, can be induced to trans-differentiate into osteoblasts in vitro and in vivo. All-trans retinoic acid (RA) induced expression of osteoblast-specific mRNAs encoding Cbfa1/Runx2, osterix, alkaline phosphatase, osteopontin, parathyroid hormone receptor, and osteocalcin in the DFAT cells, but did not induce the expression of adipocyte-specific mRNAs encoding PPARgamma2, C/EBPalpha, and GLUT4. Moreover, alkaline phosphatase activity was expressed in DFAT cells and the cells underwent mineralization of the bone matrix in vitro. Furthermore, when DFAT cells were transplanted subcutaneously into C57BL/6N mice in diffusion chambers, these cells... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=2048701 Wed, 17 Dec 2008 05:00:00 +0100 2048701 http://www.medworm.com/index.php?rid=1926871&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18957791%26dopt%3DAbstract Authors: Arai K, Nagashima Y, Takemoto T, Nishiyama T In adult mouse, the mRNA corresponding to the alpha1 chain of type XII collagen (alpha 1(XII)) is predominantly detected in the bone. Additionally, murine osteoblastic cells, MC3T3-E1, increased the mRNA level of alpha 1(XII) response to the mechanical strain in the stretch culture system. Cyclic stretch stress resulted in a threefold increase in mRNA level of alpha 1(XII) as compared to the control experiment in MC3T3-E1. Transient transfection assays employing a reporter construct, together with site-directed mutagenesis studies, suggested that the AP-1 binding site in the first exon of mouse alpha 1(XII) gene is important for stretch stress-mediated upregulation of alpha 1(XII) expression. Electrophoretic mobility shift assay and... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1926871 Wed, 29 Oct 2008 04:00:00 +0100 1926871 http://www.medworm.com/index.php?rid=1906918&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18948673%26dopt%3DAbstract Authors: Toyota N, Takano-Ohmuro H, Yoshida LS, Araki M, Yoshinobu K, Suzuki-Toyota F We herein examine the effect of cardiac troponin T (CTnT) suppression in cultured chicken cardiomyocytes derived from embryonic cardiac ventricular muscle. TnT is an important protein participating in regulation of striated muscle contraction, but it is not clear whether TnT contributes to the formation of sarcomere structure in myofibrils. Double-stranded RNA homologous to the nucleotide sequence of CTnT (CTnT-siRNA) was introduced into cultured muscle cells two days after plating. Transfection efficiency was above 80%. Immunoblot analyses suggested that the expression of CTnT progressively falls for the three consecutive days after transfection, but partly reappears on the fourth day. Maximum suppre... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1906918 Fri, 24 Oct 2008 04:00:00 +0100 1906918 http://www.medworm.com/index.php?rid=1896918&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18931453%26dopt%3DAbstract In this report, we demonstrate the feasibility of switching FCCS for enzymatic cleavage of proteins in living cells. A fusion protein of two fluorophores (EGFP and mRFP) with a cleavage site of caspase-3 inserted was expressed in HeLa cells, and proteolysis assay was performed during apoptotic cell death. Due to the absence of cross-talk signals, the FCCS measurement with the switching function gave a large change in relative cross-correlation amplitude after protein cleavage. Hence, switching FCCS enables more reliable measurement of molecular interactions than conventional FCCS. PMID: 18931453 [PubMed - in process] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1896918 Wed, 22 Oct 2008 21:53:54 +0100 1896918 http://www.medworm.com/index.php?rid=1845828&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18827403%26dopt%3DAbstract Authors: Wang Z, Xie Y, Zhang L, Zhang H, An X, Wang T, Meng A The association of the cyclin D-Cdk (DC) complex with retinoblastoma protein (pRb) is required for the G1-S transition of the cell cycle. Cyclin synthesis, nuclear localization and degradation are control mechanisms for the transition, but regulation of the DC complex nuclear import also contributes to the transition. Analysis of the timing of the G1-S transition in mammalian cell lines revealed acceleration with overexpression of cyclin D2 and Cdk4. Immunolocalization assays revealed that cyclin D2 and Cdk4 formed a complex in the cytoplasm and approached the nucleus. They accumulated on the cytosolic surfaces of the nuclear pores and then were arrested at the nuclear membrane before the nucleus reached a critical size. Fi... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1845828 Wed, 01 Oct 2008 04:00:00 +0100 1845828 http://www.medworm.com/index.php?rid=1845827&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18827404%26dopt%3DAbstract Authors: Suwastika IN, Uemura T, Shiina T, Sato MH, Takeyasu K SNAREs ('Soluble N-ethyl-maleimide sensitive factor attachment protein receptors') play a critical role in the membrane fusion step of the vesicular transport system in eukaryotes. The number of the genes encoding SNARE proteins is estimated to be 64 in Arabidopsis thaliana. This number is much larger than those in other eukaryotes, suggesting a complex membrane trafficking in plants. The Arabidopsis SNAREs, the SYP7 group proteins, SYP71, SYP72, and SYP73, form a plant-specific SNARE subfamily with not-yet-identified functions. We have previously reported that the SYP7 subfamily proteins are predominantly localized to the endoplasmic reticulum in the Arabidopsis suspension cultured cells under transient expression conditio... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1845827 Wed, 01 Oct 2008 04:00:00 +0100 1845827 http://www.medworm.com/index.php?rid=1845826&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18827405%26dopt%3DAbstract Authors: Yuasa K, Hagiwara Y, Ando M, Nakamura A, Takeda S, Hijikata T miR-1, miR-133a, and miR-206 are muscle-specific microRNAs expressed in skeletal muscles and have been shown to contribute to muscle development. To gain insight into the pathophysiological roles of these three microRNAs in dystrophin-deficient muscular dystrophy, their expression in the tibialis anterior (TA) muscles of mdx mice and CXMD(J )dogs were evaluated by semiquantitative RT-PCR and in situ hybridization. Their temporal and spatial expression patterns were also analyzed in C2C12 cells during muscle differentiation and in cardiotoxin (CTX)-injured TA muscles to examine how muscle degeneration and regeneration affect their expression. In dystrophic TA muscles of mdx mice, miR-206 expression was significantly ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1845826 Wed, 01 Oct 2008 04:00:00 +0100 1845826 http://www.medworm.com/index.php?rid=1769831&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18772531%26dopt%3DAbstract Authors: Nakagawa T, Fujiu K, Cole ES, Numata O The Tetrahymena Ca(2+)-binding protein of 25 kDa (TCBP-25) is a calmodulin family protein containing four EF-hand type calcium-binding domains. TCBP-25 is localized in the whole cell cortex and around both the migratory and stationary pronuclei at the pronuclear exchange stage during conjugation. TCBP-25 is expected to play an important role in conjugation, though its function during sexual reproduction has not been elucidated. According to the localization of this protein and its timing, three possible roles of TCBP-25 are proposed. TCBP-25 may play a role in 1) differentiating the two functional pronuclei from the degenerative post-meiotic nuclei, 2) the process of pronuclear exchange and 3) pronuclear fusion. To test these hypotheses, ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1769831 Fri, 05 Sep 2008 04:00:00 +0100 1769831 http://www.medworm.com/index.php?rid=1690247&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18685226%26dopt%3DAbstract Authors: Saito K, Kobayashi K, Tani T, Nagai T Multi-point scanning confocal microscopy using a Nipkow disk enables the acquisition of fluorescent images with high spatial and temporal resolutions. Like other single-point scanning confocal systems that use Galvano meter mirrors, a commercially available Nipkow spinning disk confocal unit, Yokogawa CSU10, requires lasers as the excitation light source. The choice of fluorescent dyes is strongly restricted, however, because only a limited number of laser lines can be introduced into a single confocal system. To overcome this problem, we developed an illumination system in which light from a mercury arc lamp is scrambled to make homogeneous light by passing it through a multi-mode optical fiber. This illumination system provides incoheren... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1690247 Wed, 06 Aug 2008 04:00:00 +0100 1690247 http://www.medworm.com/index.php?rid=1628481&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18227620%26dopt%3DAbstract Authors: Kimura H, Hayashi-Takanaka Y, Goto Y, Takizawa N, Nozaki N Histone modifications play critical roles in the epigenetic regulation of gene expression and in the maintenance of genome integrity. Acetylation and methylation of histone H3 are particularly important in gene activation and silencing. We generated and characterized a panel of mouse monoclonal antibodies that specifically recognize different modifications on K4, K9, and K27 residues on histone H3. By using these antibodies for chromatin immunoprecipitation and immunoblotting, we analyzed the relationship between different modifications in nearby nucleosomes in human cells. Within a few nucleosome neighbors, trimethyl-K4 was associated with acetyl-K27, rather than with dimethyl-K4 and acetyl-K9, consistent with their c... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628481 Wed, 16 Jul 2008 19:39:32 +0100 1628481 http://www.medworm.com/index.php?rid=1628480&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18256511%26dopt%3DAbstract Authors: Fujibayashi A, Taguchi T, Misaki R, Ohtani M, Dohmae N, Takio K, Yamada M, Gu J, Yamakami M, Fukuda M, Waguri S, Uchiyama Y, Yoshimori T, Sekiguchi K RME-8 is a DnaJ-domain-containing protein that was first identified in Caenorhabditis elegans as being required for uptake of yolk proteins. RME-8 has also been identified in other species, including flies and mammals, and the phenotypes of their RME-8 mutants suggest the importance of this protein in endocytosis. In the present study, we cloned human RME-8 (hRME-8) and characterized its biochemical properties and functions in endocytic pathways. hRME-8 was found to be a peripheral protein that was tightly associated with the membrane via its N-terminal region. It partially colocalized with several early endosomal markers, but no... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628480 Wed, 16 Jul 2008 19:39:32 +0100 1628480 http://www.medworm.com/index.php?rid=1628479&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18256512%26dopt%3DAbstract In this study, we demonstrate that these structures are not cytosolic aggregates but lysosomes that have accumulated the GFP-like proteins. Our biochemical and immunocytochemical experiments have revealed that certain GFP-like proteins expressed in the cytosol enter lysosomes possibly by an autophagy-related mechanism, but retain their fluorescence because of resistance not only to acidity but also to lysosomal proteases. PMID: 18256512 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628479 Wed, 16 Jul 2008 19:39:32 +0100 1628479 http://www.medworm.com/index.php?rid=1628478&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18285636%26dopt%3DAbstract Authors: Yoshida H, Tomita H, Sugano E, Isago H, Ishiguro S, Tamai M To investigate the effect of brain derived neurotrophic factor (BDNF) on the phagocytic activity in iris pigment epithelial (IPE) cells, purified porcine photoreceptor outer segments (POS) were applied to cultured IPE cells for three hours. To measure phagocytic activities, bound and total POS were differentially stained using a double immunofluorescence staining method. BDNF increased the binding of POS in IPE cells in a dose-dependent manner. Ingestion of POS, however, was not affected throughout the concentrations used in this study. To investigate the signal transduction pathways of BDNF, a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, and MAPK/ERK kinase (MEK) inhibitor, PD98059, were used for this st... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628478 Wed, 16 Jul 2008 19:39:32 +0100 1628478 http://www.medworm.com/index.php?rid=1628476&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18296860%26dopt%3DAbstract Authors: Goto S, Okada N, Kaneko A, Isemura M In view of the importance of vitamin A in the human immune system and the central role of interleukin-2 (IL-2) in the proliferation of T-lymphocytes, we examined the effects of all-trans-retinoic acid (ATRA) on the protein and gene expression of IL-2 in the human T-cell line HUT-78 when stimulated with either 12-O-tetradecanoylphorbol-13-acetate (TPA) or phytohemagglutinin (PHA). ATRA enhanced the production of IL-2 stimulated by TPA, but suppressed that stimulated by PHA. These findings were consistent with the results of a reverse transcription-polymerase chain reaction and quantitative real-time polymerase chain reaction examining IL-2 gene expression. ATRA augmented the gene expression of PKC-beta1 up-regulated by TPA and restored that ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628476 Wed, 16 Jul 2008 19:39:32 +0100 1628476 http://www.medworm.com/index.php?rid=1628475&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18344600%26dopt%3DAbstract Authors: Nagasaki A, Inotsume K, Kanada M, Uyeda TQ NBT-II cells on collagen-coated substrates move rapidly and persistently, maintaining a semi-circular shape with a large lamellipodium, in a manner similar to fish keratocytes. The inhibitor of phospholipase D (PLD), n-butanol, completely blocked the migration and disturbed the characteristic localization of actin along the edge of lamellipodia. To investigate the functional difference between the two isozymes of PLD (PLD1 and PLD2), we transfected NBT-II cells with vectors expressing shRNA to deplete PLD1 or PLD2. Depletion of both PLD1 and 2 by RNA interference reduced the velocity of the migration, but depletion of PLD2 inhibited motility more severely than that of PLD1. Furthermore, GFP-PLD2 was localized to the protruding regions... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628475 Wed, 16 Jul 2008 19:39:32 +0100 1628475 http://www.medworm.com/index.php?rid=1628474&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18360008%26dopt%3DAbstract In this study, we performed a genome-wide search for ATF6alpha-target genes in mice. Only 30 of the 14,729 analyzable genes were identified as specific targets, of which 40% were ER quality control proteins, 20% were ER proteins, while the rest had miscellaneous functions. The negative effects of the absence of PERK on transcriptional induction of ER quality control proteins could be explained by its inhibitory effect on ATF6alpha activation. Further, proteins involved in transport from the ER are not regulated by ATF6alpha, and transport of folded cargo molecules from the ER was not affected by the absence of ATF6alpha. Based on these results, we propose that ATF6 is a transcription factor specialized in the regulation of ER quality control proteins. PMID: 18360008 [PubMed - indexed f... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628474 Wed, 16 Jul 2008 19:39:31 +0100 1628474 http://www.medworm.com/index.php?rid=1628473&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18360009%26dopt%3DAbstract In this study we addressed the mechanism. Immunochemical studies revealed that HNE preferentially modified alpha-tubulin in rat primary neuronal cells, PC12 cells, and rat fibroblast cell line 3Y1 cells. This was morphologically associated with the disappearance of microtubule structures in those cells. In a purified rat brain microtubule fraction, HNE modified unpolymerized tubulin and impaired its polymerizability, with a concomitant increase in insolubilized tubulin. Nevertheless, HNE had a marginal effect on the stability of pre-polymerized microtubules. These results suggest that disruption of microtubule assembly as a result of HNE modification of unpolymerized tubulin, rather than destruction of assembled microtubules, is responsible for the disappearance of microtubule structures i... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628473 Wed, 16 Jul 2008 19:39:31 +0100 1628473 http://www.medworm.com/index.php?rid=1628472&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18367816%26dopt%3DAbstract Authors: Yanagida-Ishizaki Y, Takei T, Ishizaki R, Imakagura H, Takahashi S, Shin HW, Katoh Y, Nakayama K Tom1 (target of Myb 1) and its related proteins (Tom1L1/Srcasm and Tom1L2) constitute a protein family, which share an N-terminal VHS (Vps27, Hrs and STAM) domain and a following GAT (GGA and Tom1) domain. Tom1L1 has potential binding sequences for Tsg101, which is one of key regulators of the multivesicular body (MVB) formation. To obtain a clue to the role of Tom1L1 in the MVB formation, we have characterized the Tom1L1-Tsg101 interaction. We have found that not only the PTAP sequence in the GAT domain but also the PSAP sequence in the C-terminal region of Tom1L1 is responsible for its interaction with the UEV domain of Tsg101 and competes with the HIV-1 Gag protein for the Tsg10... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628472 Wed, 16 Jul 2008 19:39:31 +0100 1628472 http://www.medworm.com/index.php?rid=1628470&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18388399%26dopt%3DAbstract Authors: Kimura S, Noda T, Yoshimori T Autophagy is a membrane trafficking pathway that carries cytosolic components to the lysosome for degradation. During this process, the autophagosome, a double-membraned organelle, is generated de novo, sequesters cytoplasmic proteins and organelles, and delivers them to lysosomes. However, the mechanism by which autophagosomes are targeted to lysosomes has not been determined. Here, we observed the real-time behavior of microtubule-associated protein light chain 3 (LC3), which localizes to autophagosomes, and showed that autophagosomes move in a microtubule- and dynein-dynactin motor complex-dependent manner. After formation, autophagosomes show a rapid vectorial movement in the direction of the centrosome, where lysosomes are usually concentrate... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628470 Wed, 16 Jul 2008 19:39:31 +0100 1628470 http://www.medworm.com/index.php?rid=1628469&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18497446%26dopt%3DAbstract In this study, we examined the molecular organization on the cytoplasmic surface of the substratum-facing plasma membrane, focusing on Rac1 and its effectors, IQGAP1 and Sra-1, by electron microscopy. We employed deep-etch immunoreplica methods to observe the membrane cytoskeletal architecture while determining molecular locations. Beneath the plasma membrane, Rac1 and its effectors showed similar, but distinct, destinations. Rac1 localized on the membrane and associated with the membrane cytoskeleton. IQGAP1 predominantly localized beside actin filaments and occasionally near microtubules together with Rac1. On the other hand, Sra-1 localized at actin filaments, microtubules, and the plasma membrane. Sra-1 colabeled with Rac1 was mainly found at the membrane and actin filaments. These res... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628469 Wed, 16 Jul 2008 19:39:31 +0100 1628469 http://www.medworm.com/index.php?rid=1628471&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18388398%26dopt%3DAbstract Authors: Tsuda K, Furuta N, Inaba H, Kawai S, Hanada K, Yoshimori T, Amano A Porphyromonas gingivalis, a periodontal pathogen, was previously suggested to exploit alpha5beta1 integrin and lipid rafts to invade host cells. However, it is unknown if the functional roles of these host components are divided on the bacterial invasion. In the present study, we analyzed the mechanisms underlying P. gingivalis invasion, using fluorescent beads coated with bacterial membrane vesicles (MV beads). Cholesterol depletion reagents including methyl-beta-cyclodextrin (MbetaCD) drastically inhibited the entry of MV beads into epithelial cells, while they were less effective on bead adhesion to the cells. Bead entry was also abolished in CHO cells deficient in sphingolipids, components of lipid rafts, ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628471 Fri, 04 Apr 2008 04:00:00 +0100 1628471 http://www.medworm.com/index.php?rid=1628498&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17159328%26dopt%3DAbstract Authors: Kyuuma M, Kikuchi K, Kojima K, Sugawara Y, Sato M, Mano N, Goto J, Takeshita T, Yamamoto A, Sugamura K, Tanaka N The appropriate sorting of vesicular cargo, including cell-surface proteins, is critical for many cellular functions. Ubiquitinated cargo is targeted to endosomes and digested by lysosomal enzymes. We previously identified AMSH, a deubiquitination enzyme (DUB), to be involved in vesicular transport. Here, we purified an AMSH-binding protein, CHMP3, which is an ESCRT-III subunit. ESCRT-III functions on maturing endosomes, indicating AMSH might also play a role in MVB/late endosomes. Expression of an AMSH mutant lacking CHMP3-binding ability resulted in aberrant endosomes with accumulations of ubiquitinated cargo. Nevertheless, CHMP3-binding capability was not essenti... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628498 Mon, 01 Jan 2007 05:00:00 +0100 1628498 http://www.medworm.com/index.php?rid=1628496&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17229992%26dopt%3DAbstract Authors: Cena A, Orlowski J, Machula K, Fronk J, Kurlandzka A The sister chromatid cohesion complex of Saccharomyces cerevisiae is composed of proteins termed cohesins. The complex forms a ring structure that entraps sister DNAs, probably following replication. The mechanism of cohesion is universal and the proteins participating in this process are evolutionarily highly conserved. We investigated the Irr1p/Scc3p cohesin subunit, an under-studied protein. We show that the presence of a mutated copy of IRR1 gene, encoding the F658G substitution in Irr1p, changes the sensitivity of the heterozygous irr1-1/IRR1 diploid to cell wall-affecting compounds. Microscopic images indicate that chitin distribution in the mutant cell wall is affected, although the biochemical composition of the cell... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628496 Mon, 01 Jan 2007 05:00:00 +0100 1628496 http://www.medworm.com/index.php?rid=1628495&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17314458%26dopt%3DAbstract Authors: Fukano T, Sawano A, Ohba Y, Matsuda M, Miyawaki A Although the consequences of Ras activation have been studied extensively in the context of oncogenesis, its regulation in physiological modes of signal transduction is not well understood. A fluorescent indicator, Raichu-Ras, was fused to the C-terminal hypervariable regions of H-Ras and K-Ras to create indicators for Ras activation within caveolae/rafts (Raichu-tH) and non-raft domains (Raichu-tK) of the plasma membrane, respectively. Raichu-tH was also found abundantly in endomembranes. To monitor Ras activation with high spatial resolution, it is imperative to observe sectioned images of the signals. We have developed a wide-field fluorescence microscope equipped with a digital micromirror device (DMD) to acquire optically ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628495 Mon, 01 Jan 2007 05:00:00 +0100 1628495 http://www.medworm.com/index.php?rid=1628494&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17314459%26dopt%3DAbstract Authors: Ishikawa R, Shingyoji C A basic feature of the movement of eukaryotic flagella is oscillation. Although flagellar oscillation is thought to be regulated by a self-regulatory feedback system including the mechanical signal of bending itself, the mechanism regulating the dynein motile activity to produce oscillation is not well understood. To elucidate the mechanism, we developed a new experimental system which allowed us to analyze the conditions necessary for the induction of oscillation. When a mechanical signal of bending or a pulse was applied by micromanipulation to a demembranated motionless sea urchin sperm flagellar axoneme at very low ATP concentrations (1-3 microM), a localized pair of bends was induced. The bend formation was often followed by further responses inclu... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628494 Mon, 01 Jan 2007 05:00:00 +0100 1628494 http://www.medworm.com/index.php?rid=1628493&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17460350%26dopt%3DAbstract Authors: Hino M, Wada S, Tajika Y, Morimura Y, Hamada N, Funayama T, Sakashita T, Kakizaki T, Kobayashi Y, Yorifuji H The effects of heavy ion microbeams on muscle fibers isolated from mouse skeletal muscles were examined by electron microscopy. The plasma membranes of heavy ion beam-irradiated areas of muscle fibers showed irregular protrusions and invaginations. In the cytoplasm, an irregular distribution of microfilaments was found near the plasma membrane. Sarcoplasmic reticula in the irradiated regions showed a distended appearance with flocculent material within the lumen. These changes were seen as early as 2 min after irradiation, and persisted until as late as 22 min after irradiation. Many autophagic vacuoles could be seen at 7 min after irradiation. At 22 min, the vacuoles b... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628493 Mon, 01 Jan 2007 05:00:00 +0100 1628493 http://www.medworm.com/index.php?rid=1628492&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17507765%26dopt%3DAbstract Authors: Mizobuchi N, Hoseki J, Kubota H, Toyokuni S, Nozaki J, Naitoh M, Koizumi A, Nagata K Arginine rich, mutated in early stage of tumors (ARMET) was first identified as a human gene highly mutated in a variety of cancers. However, little is known about the characteristics of the ARMET protein and its expression. We identified ARMET as a gene upregulated by endoplasmic reticulum (ER) stress. Here, we show that the mouse homologue of ARMET is an 18-kDa soluble ER protein that is mature after cleavage of a signal sequence and has four intramolecular disulfide bonds, including two in CXXC sequences. ER stress stimulated ARMET expression, and the expression patterns of ARMET mRNA and protein in mouse tissues were similar to those of Grp78, an Hsp70-family protein required for quality c... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628492 Mon, 01 Jan 2007 05:00:00 +0100 1628492 http://www.medworm.com/index.php?rid=1628491&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17575411%26dopt%3DAbstract Authors: Hamaguchi Y, Numata T, K Satoh S Polar body formation is an extremely unequal cell division. In order to understand the mechanism of polar body formation, morphological changes at the animal pole were investigated in living oocytes of the starfish, Asterina pectinifera, and the amounts of cortical actin filaments were quantitatively estimated after staining the maturing oocytes with fluorescently-labeled phallotoxins using a computer and image-processing software. Formation of a bulge, which is presumed to become a polar body, and the anaphase separation of chromosomes occurred simultaneously. When the bulge became large, one group of chromatids moved into the bulge. The dividing furrow then formed and finally a polar body formed. Just at the time of bulge formation, the inten... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628491 Mon, 01 Jan 2007 05:00:00 +0100 1628491 http://www.medworm.com/index.php?rid=1628490&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17575412%26dopt%3DAbstract Authors: Kato M, Kato Y, Nishida M, Hayakawa T, Haraguchi T, Hiraoka Y, H Inoue Y, Yamaguchi M Three subtypes of HP1, a conserved non-histone chromosomal protein enriched in heterochromatin, have been identified in humans, HP1alpha, beta and gamma. In the present study, we utilized a Drosophila system to characterize human HP1 functions. Over-expression of HP1beta in eye imaginal discs caused abnormally patterned eyes, with reduced numbers of ommatidia, and over-expression of HP1gamma in wing imaginal discs caused abnormal wings, in which L4 veins were gapped. These phenotypes were specific to the HP1 subtypes and appear to reflect suppressed gene expression. To determine the molecular domains of HP1 required for each specific phenotype, we constructed a series of chimeric molecules wi... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628490 Mon, 01 Jan 2007 05:00:00 +0100 1628490 http://www.medworm.com/index.php?rid=1628489&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17634669%26dopt%3DAbstract Authors: Kaburagi Y, Okochi H, Satoh S, Yamashita R, Hamada K, Ikari K, Yamamoto-Honda R, Terauchi Y, Yasuda K, Noda M To analyze the functional differences of the insulin receptor substrate (IRS) family, the N-terminal fragments containing the pleckstrin homology (PH) domains and the phosphotyrosine-binding (PTB) domains of IRS (IRS-N) proteins, as well as intact IRS molecules, were expressed in Cos-1 cells, and insulin-induced tyrosine phosphorylation and subcellular distribution of IRS proteins were analyzed. In contrast to the distinct affinities toward phosphoinositides, these IRS-N fragments non-selectively inhibited insulin-induced tyrosine phosphorylation of IRS-1, IRS-2 and IRS-3, among which IRS3-N was most effective. The mutations of IRS-1 disrupting all the phosphoinositide... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628489 Mon, 01 Jan 2007 05:00:00 +0100 1628489 http://www.medworm.com/index.php?rid=1628488&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17785912%26dopt%3DAbstract Authors: Kusumi N, Watanabe M, Yamada H, Li SA, Kashiwakura Y, Matsukawa T, Nagai A, Nasu Y, Kumon H, Takei K Tubulobulbar complexes (TBCs) are composed of several tubular invaginations formed at the plasma membrane of testicular Sertoli cells. TBCs are transiently formed at the contact region with spermatids at spermatogenic stage VII in rat and mouse, and such TBC formation is prerequisite for spermatid release. Since the characteristic structure of TBCs suggests that the molecules implicated in endocytosis could be involved in TBC formation, we here investigated the localization and physiological roles of endocytic proteins, amphiphysin 1 and dynamin 2, at TBCs. We demonstrated by immunofluorescence that the endocytic proteins were concentrated at TBCs, where they colocalized with c... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628488 Mon, 01 Jan 2007 05:00:00 +0100 1628488 http://www.medworm.com/index.php?rid=1628487&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17917305%26dopt%3DAbstract Authors: Hotta T, Haraguchi T, Mizuno K In higher plant cells, various microtubular arrays can be seen despite of their lack of structurally defined microtubule-organizing centers (MTOCs) like centrosomes in animal cells. Little is known about the molecular properties of the microtubule-organizing centers in higher plant cells. The nuclear surface contains one of these microtubule-organizing centers and generates microtubules radially toward the cell periphery (radial microtubules). Previously, we reported that histone H1 possessed the microtubule-organizing activity, and it was suggested that histone H1 localized on the nuclear surfaces in Tobacco BY-2 cells (Nakayama, T., Ishii, T., Hotta, T., and Mizuno, K. J. Biol. Chem. (submitted)). Here we show that histone H1 forms ring-shaped ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628487 Mon, 01 Jan 2007 05:00:00 +0100 1628487 http://www.medworm.com/index.php?rid=1628486&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17951964%26dopt%3DAbstract Authors: Ichihara K, Shimizu H, Taguchi O, Yamaguchi M, Inoue YH It is important for the proper execution of cell division in both mitosis and meiosis that the chromosome segregation, cytokinesis, and partition of cell organelles progress in smooth coordination. We show here that the mitochondria inheritance is closely linked with microtubules during meiotic divisions in Drosophila males. They are first clustered in a cell equator at metaphase associated with astral microtubules and then distributed along central spindle microtubules after anaphase. The molecular mechanism for the microtubule-dependent inheritance of mitochondria in male meiosis has not been demonstrated yet. We first isolated mutations for a larp gene that is highly conserved among eukaryotes and showed that these mut... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628486 Mon, 01 Jan 2007 05:00:00 +0100 1628486 http://www.medworm.com/index.php?rid=1628485&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17984568%26dopt%3DAbstract Authors: Kawano K, Ebisawa M, Hase K, Fukuda S, Hijikata A, Kawano S, Date Y, Tsuneda S, Itoh K, Ohno H Pregnancy-specific glycoproteins (Psgs) secreted by the placenta regulate the immune system to ensure the survival of the fetal allograft by inducing IL-10, an anti-inflammatory cytokine. However, it is unknown whether Psgs are involved in more general aspects of immune response other than maternal immunity. Here, we report that Psg18 is highly expressed in the follicle-associated epithelium (FAE) overlaying Peyer's patches (PPs). Bioinformatics analysis with Reference Database for Immune Cells (RefDIC) as well as RT-PCR data demonstrated that Psg18 is exclusively expressed in FAE in adult mice, in contrast to other Psg family members that are either not expressed or only slightly ex... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628485 Mon, 01 Jan 2007 05:00:00 +0100 1628485 http://www.medworm.com/index.php?rid=1628484&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18057801%26dopt%3DAbstract Authors: Sano Y, Shimizu F, Nakayama H, Abe M, Maeda T, Ohtsuki S, Terasaki T, Obinata M, Ueda M, Takahashi R, Kanda T In autoimmune disorders of the peripheral nervous system (PNS) such as Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy, breakdown of the blood-nerve barrier (BNB) has been considered as a key step in the disease process. Hence, it is important to know the cellular property of peripheral nerve microvascular endothelial cells (PnMECs) constituting the bulk of BNB. Although many in vitro models of the blood-brain barrier (BBB) have been established, very few in vitro BNB models have been reported so far. We isolated PnMECs from transgenic rats harboring the temperature-sensitive SV40 large T-antigen gene (tsA58 rat) and investiga... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628484 Mon, 01 Jan 2007 05:00:00 +0100 1628484 http://www.medworm.com/index.php?rid=1628483&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18159124%26dopt%3DAbstract Authors: Sugano W, Yamaguchi M Myeloid leukemia factor 1 (MLF1) was first identified as part of a leukemic fusion protein produced by a chromosomal translocation, and MLF family proteins are present in many animals. In mammalian cells, MLF1 has been described as mainly cytoplasmic, but in Drosophila, one of the dMLF isoforms (dMLFA) localized mainly in the nucleus while the other isoform (dMLFB), that appears to be produced by the alternative splicing, displays both nuclear and cytoplasmic localization. To investigate the difference in subcellular localization between MLF family members, we examined the subcellular localization of deletion mutants of dMLFA isoform. The analyses showed that the C-terminal 40 amino acid region of dMLFA is necessary and sufficient for nuclear localization... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628483 Mon, 01 Jan 2007 05:00:00 +0100 1628483 http://www.medworm.com/index.php?rid=1628482&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18159125%26dopt%3DAbstract Authors: Liu H, Komiya S, Shimizu M, Fukunaga Y, Nagafuchi A P120 plays an essential role in cadherin turnover. The molecular mechanism involved, however, remains only partially understood. Here, using a gene trap targeting technique, we replaced the genomic sequence of p120 with HA-tagged p120 cDNA in mouse teratocarcinoma F9 cells. In the p120 knock-in (p120KI) cells, we found that the expression level of p120 was severely reduced and that the expression level of other components of the cadherin-catenin complex was also reduced. The stable expression of various p120 mutants in p120KI cells revealed that the armadillo repeat domain of p120 is sufficient to restore the expression level of E-cadherin. In p120KI cells, internalized E-cadherin was frequently detected as large aggregates. ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628482 Mon, 01 Jan 2007 05:00:00 +0100 1628482 http://www.medworm.com/index.php?rid=1628477&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18285637%26dopt%3DAbstract Authors: Chikashige Y, Tsutsumi C, Okamasa K, Yamane M, Nakayama J, Niwa O, Haraguchi T, Hiraoka Y Imbalances of gene expression in aneuploids, which contain an abnormal number of chromosomes, cause a variety of growth and developmental defects. Aneuploid cells of the fission yeast Schizosaccharomyces pombe are inviable, or very unstable, during mitotic growth. However, S. pombe haploid cells bearing minichromosomes derived from the chromosome 3 can grow stably as a partial aneuploid. To address biological consequences of aneuploidy, we examined the gene expression profiles of partial aneuploid strains using DNA microarray analysis. The expression of genes in disomic or trisomic cells was found to increase approximately in proportion to their copy number. We also found that some genes ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628477 Mon, 01 Jan 2007 05:00:00 +0100 1628477 http://www.medworm.com/index.php?rid=1628513&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16508205%26dopt%3DAbstract Authors: Iwamoto R, Mekada E The epidermal growth factor (EGF)-ErbB signaling network is composed of multiple ligands of the EGF family and four tyrosine kinase receptors of the ErbB family. In higher vertebrates, these four receptors bind a multitude of ligands. Ligand binding induces the formation of various homo- and heterodimers of ErbB, potentially providing for a high degree of signal diversity. ErbB receptors and their ligands are expressed in a variety of tissues throughout development. Recent advances in gene targeting strategies in mice have revealed that the EGF-ErbB signaling network has fundamental roles in development, proliferation, differentiation, and homeostasis in mammals. The heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of growth fac... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628513 Sun, 01 Jan 2006 05:00:00 +0100 1628513 http://www.medworm.com/index.php?rid=1628512&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16557002%26dopt%3DAbstract Authors: Wang X, Mizushima H, Adachi S, Ohishi M, Iwamoto R, Mekada E Heparin-binding EGF-like growth factor (HB-EGF) is synthesized as a transmembrane precursor protein that is anchored to the plasma membrane. The extracellular EGF-like domain acts as a mitogen and motogen upon ectodomain shedding, but the functional roles of the transmembrane and cytoplasmic domains are largely unknown. We demonstrate here that cytoplasmic domain of HB-EGF is phosphorylated by external stimuli, and that the phosphorylation site is involved in HB-EGF-dependent tumorigenesis. Treatment of Vero cells overexpressing human HB-EGF with 12-O-tetradecanoylphorbol-13-acetate (TPA) caused ectodomain shedding of HB-EGF and generated two carboxyl (C)-terminal fragments with distinct electrophoretic mobilities. M... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628512 Sun, 01 Jan 2006 05:00:00 +0100 1628512 http://www.medworm.com/index.php?rid=1628511&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16565574%26dopt%3DAbstract Authors: Ohkumo T, Masutani C, Eki T, Hanaoka F Defects in the human XPV/POLH gene result in the variant form of the disease xeroderma pigmentosum (XP-V). The gene encodes DNA polymerase eta (Poleta), which catalyzes translesion synthesis (TLS) past UV-induced cyclobutane pyrimidine dimers (CPDs) and other lesions. To further understand the roles of Poleta in multicellular organisms, we analyzed phenotypes caused by suppression of Caenorhabditis elegans POLH (Ce-POLH) by RNA interference (RNAi). F1 and F2 progeny from worms treated by Ce-POLH-specific RNAi grew normally, but F1 eggs laid by worms treated by RNAi against Ce-POLD, which encodes Poldelta did not hatch. These results suggest that Poldelta but not Poleta is essential for C. elegans embryogenesis. Poleta-targeted embryos UV-... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628511 Sun, 01 Jan 2006 05:00:00 +0100 1628511 http://www.medworm.com/index.php?rid=1628510&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16648663%26dopt%3DAbstract Authors: Shimohira-Yamasaki M, Toda S, Narisawa Y, Sugihara H Merkel cells have been assumed to guide nerve fibers to the skin. However, there has been little in vitro evidence that supports this hypothesis, because there is no suitable established culture system of Merkel cells. Here we show that Merkel cells isolated from rat footpad skin were successfully cultured in a monolayer with keratinocytes. Keratinocytes did not affect any structural changes in Merkel cells. When nerve cells (NG108-15 or PC12) were added to the culture system, both nerve fibers and cytoplasmic processes of Merkel cells outgrew and cooperatively organized synapse-like structures at their contact points. Nerve cells promoted Merkel cell survival, compared with keratinocytes only. Merkel cell proliferation was ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628510 Sun, 01 Jan 2006 05:00:00 +0100 1628510 http://www.medworm.com/index.php?rid=1628509&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16951535%26dopt%3DAbstract Authors: Tsutsumi K, Yasuda M, Nishioka T Radiotherapy is an effective approach to treating many types of cancer. Recent progress in radiotherapy technology, such as intensity-modulated radiation therapy (IMRT) and three-dimensional (3D) radiotherapy, allow precise energy transfer to the tumor, which has improved local control rates. However, the emergence of tolerant cells during or after radiotherapy remains problematic. In the present study, we first established a cell population from H1299, the p53-null non-small cell lung cancer cell line, by 10 Gy irradiation using 6 MV X-rays. The radio- and chemosensitivity of this cell population (referred to as H1299-IR) was determined using colony formation analyses and MTS assays. Compared with the parental cell line, the radiosensitivity o... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628509 Sun, 01 Jan 2006 05:00:00 +0100 1628509 http://www.medworm.com/index.php?rid=1628508&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16988490%26dopt%3DAbstract Authors: Ko SY, Kang HY, Lee HS, Han SY, Hong SH Mouse embryonic stem (mES) cells can be maintained in undifferentiated state in the presence of a cytokine, leukemia inhibitory factor (LIF). Many investigators found that STAT3 activation is important for the maintenance of pluripotency by LIF. However, the downstream pathways of STAT3 activation are still unknown. To look for STAT3-downstream target genes, we performed DD-RT PCR in the presence or absence of LIF. Through further confirmation, we finally selected 8 genes whose expressions were significantly dependent upon the presence of LIF. Among them, Jmjd1a was down-regulated after LIF withdrawal, and it was selected for further investigation. Its expression started to decrease 1 day after the removal of LIF, and disappeared on day ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628508 Sun, 01 Jan 2006 05:00:00 +0100 1628508 http://www.medworm.com/index.php?rid=1628507&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17062999%26dopt%3DAbstract Authors: Sakane H, Yamamoto T, Tanaka K Drs2p, the catalytic subunit of the Cdc50p-Drs2p putative aminophospholipid translocase, has been implicated in conjunction with the Arf1 signaling pathway in the formation of clathrin-coated vesicles (CCVs) from the TGN. Herein, we searched for Arf regulator genes whose mutations were synthetically lethal with cdc50Delta, and identified the Arf GAP gene GCS1. Most of the examined transport pathways in the Cdc50p-depleted gcs1Delta mutant were nearly normal, including endocytic transport to vacuoles, carboxypeptidase Y sorting, and the processing and secretion of invertase. In contrast, this mutant exhibited severe defects in the early endosome-to-TGN transport pathway; proteins that are transported via this pathway, such as the v-SNARE Snc1p, th... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628507 Sun, 01 Jan 2006 05:00:00 +0100 1628507 http://www.medworm.com/index.php?rid=1628506&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17063000%26dopt%3DAbstract Authors: Ishida T, Hatae T, Nishi N, Araki N The endolymphatic sac (ES) is believed to play an important role in maintaining homeostasis in the inner ear by the absorption and endocytosis of endolymph. Megalin is a 600-kDa multiligand endocytic receptor expressed in certain types of absorptive epithelia including kidney proximal tubules. We analyzed the immunoreactivity for megalin in rat ES by immunofluorescence, immunogold electron microscopy, and immunoblotting. With immunostaining, the luminal substances of the ES were strongly stained for megalin. Megalin was also localized in luminal macrophage-like cells and both types of epithelial cell (mitochondria-rich cells and ribosome-rich cells). In these cells, the megalin was localized in the lumen of endosomes, but was not membrane as... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628506 Sun, 01 Jan 2006 05:00:00 +0100 1628506 http://www.medworm.com/index.php?rid=1628505&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17072087%26dopt%3DAbstract In this report, first, we demonstrated the advantages of photoactivating PA-GFP, a variant of the Aequorea victoria green fluorescent protein (GFP), with multiphoton laser light rather than single-photon laser light, in terms of photoactivation efficiency and spatial resolution. We then applied the multiphoton photoactivation technique to selectively photoactivate the TfR tagged with PA-GFP (PA-GFP-TfR) at the TGN, and monitored the movement of the photoactivated PA-GFP-TfR in live cells. We observed that the PA-GFP-TfR photoactivated at the TGN are transported to the Tfn(+)EEA1(+) endosomal compartments after exiting the TGN. These data support the notion that early endosomes can serve as a sorting station for not only internalized plasma membrane proteins in the endocytic pathway but als... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628505 Sun, 01 Jan 2006 05:00:00 +0100 1628505 http://www.medworm.com/index.php?rid=1628504&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17110784%26dopt%3DAbstract Authors: Kayamori T, Miyake N, Akiyama N, Aimi M, Wakayama J, Kunioka Y, Yamada T The mechanical strength of sarcomere structures of skeletal muscle was studied by rupturing single myofibrils of rabbit psoas muscle by submicromanipulation techniques. Microbeads coated with alpha-actinin were attached to the surface of myofibrils immobilized to coverslip. By use of either optical tweezers or atomic force microscope, the attached beads were captured and detached from the myofibrils. During the detachment of the beads, the actin filaments bound specifically to the beads were peeled off from the bulk structures of myofibrils, thus rupturing the peripheral components of the myofibrils bound to the actin filaments. By analyzing the ruptures thus produced in various myofibril preparations, it... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628504 Sun, 01 Jan 2006 05:00:00 +0100 1628504 http://www.medworm.com/index.php?rid=1628503&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17110785%26dopt%3DAbstract Authors: Yoshida H, Nadanaka S, Sato R, Mori K XBP1 is a transcription factor downstream of IRE1, a transmembrane protein in the endoplasmic reticulum (ER) which functions as a sensor and transducer of ER stress. XBP1 mRNA is constitutively expressed at a low level as an intron-containing precursor mRNA (unspliced mRNA), which is subject to IRE1-mediated splicing reaction upon ER stress to produce the active form of XBP1, pXBP1(S). Because the XBP1 promoter carries a perfect ER stress-response element, namely, the cis-acting element responsible for the induction of ER chaperones, and XBP1 mRNA is induced in response to ER stress with a time course similar to that of ER chaperone mRNAs, it is conjectured that transcription factor ATF6, activated immediately upon ER stress, induces the t... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628503 Sun, 01 Jan 2006 05:00:00 +0100 1628503 http://www.medworm.com/index.php?rid=1628502&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17110786%26dopt%3DAbstract Authors: Nadanaka S, Yoshida H, Sato R, Mori K Mammalian transcription factor ATF6 is constitutively synthesized as a type II transmembrane protein embedded in the endoplasmic reticulum (ER). It is activated when unfolded proteins are accumulated in the ER under ER stress through a process called regulated intramembrane proteolysis (Rip), in which ATF6 is transported from the ER to the Golgi apparatus where it undergoes sequential cleavage by Site-1 and Site-2 proteases. The cytosolic transcription factor domain of ATF6 liberated from the Golgi membrane enters the nucleus where it activates transcription of ER-localized molecular chaperones and folding enzymes, leading to the maintenance of the homeostasis of the ER. Here, we analyzed M19 cells, a mutant of Chinese hamster ovary cells ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628502 Sun, 01 Jan 2006 05:00:00 +0100 1628502 http://www.medworm.com/index.php?rid=1628501&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17130669%26dopt%3DAbstract In this study, we evoked ER stress under more physiological conditions, namely, glucose starvation, and analyzed its consequence for ATF6 activation. Glucose starvation activated ATF6 and induced the ER chaperone BiP, albeit weakly. ATF6 was thus dissociated from BiP, transported to the Golgi apparatus, and cleaved. Glucose starvation enhanced the synthesis of ATF6 approximately two-fold, probably via transcriptional induction. Importantly, reduction of disulfide bridges and transport of reduced monomer occurred in response to glucose starvation. We conclude that ER stress-induced reduction of ATF6 represents a general feature of the ATF6 activation process. PMID: 17130669 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628501 Sun, 01 Jan 2006 05:00:00 +0100 1628501 http://www.medworm.com/index.php?rid=1628500&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17146146%26dopt%3DAbstract In this study, we examined the effect of 3-methlyadenine (3-MA), which shows a distinct specificity to the PI3K classes from wortmannin and LY294002, on the macropinosome formation and fusion in EGF-stimulated A431 cells. Unlike wortmannin or LY294002, 3-MA did not inhibit the uptake of fluorescent dextran by macropinocytosis. However, the fusion of macropinosomes was inhibited by 3-MA. By imaging of live-cells expressing fluorescent protein-fused tandem FYVE domains, we found that PtdIns(3)P appeared on the macropinosomal membrane shortly after the closure of macropinocytic cups and remained on macropinosomes even at 60-min age. The production of PtdIns(3)P and the recruitment of EEA1 to macropinosomes were abolished by the 3-MA treatment. Therefore, it is likely that 3-MA impairs recruit... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628500 Sun, 01 Jan 2006 05:00:00 +0100 1628500 http://www.medworm.com/index.php?rid=1628499&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17159290%26dopt%3DAbstract Authors: Hashimoto R, Yamaguchi M One of the proposed roles of sarcoglycan is to stabilize dystrophin glycoprotein complexes in muscle sarcolemma. Involvement in signal transduction has also been proposed and abnormalities in some sarcoglycan genes are known to be responsible for muscular dystrophy. While characterization of sarcoglycans in muscle has been performed, little is known about its functions in the non-muscle tissues in which mammalian sarcoglycans are expressed. Here, we investigated temporal and spatial expression patterns of Drosophila beta-sarcoglycan (dScgbeta) during development by immunohistochemistry. In addition to almost ubiquitous expression in various tissues and organs, as seen for its mammalian counterpart, anti-dScgbeta staining data of embryos, eye imaginal d... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628499 Sun, 01 Jan 2006 05:00:00 +0100 1628499 http://www.medworm.com/index.php?rid=1628497&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17202724%26dopt%3DAbstract Authors: Itadani A, Nakamura T, Shimoda C Myo1, a heavy chain of type I myosin of the fission yeast Schizosaccharomyces pombe, is essential for sporulation. Here we have analyzed the expression, localization and cellular function of the type I myosin light chain calmodulin, Cam2, encoded by cam2(+). Transcription of cam2(+) was constitutive and markedly enhanced in meiosis. The cam2 null mutant was viable and completed sporulation normally at 28 degrees C, but formed four-spored asci poorly at 34 degrees C. In those sporulation-defective cells, the forespore membrane was formed abnormally. A Cam2-GFP fusion protein accumulated at the cell poles in interphase cells and at the medial septation site in postmitotic cells, colocalizing with Myo1 and F-actin patches. During the mating proces... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628497 Sun, 01 Jan 2006 05:00:00 +0100 1628497 http://www.medworm.com/index.php?rid=1628530&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840943%26dopt%3DAbstract Authors: Matsushima K, Aosaki M, Tokuraku K, Hasan MR, Nakagawa H, Kotani S The microtubule-binding domain of MAP4, a ubiquitous microtubule-associated protein, contains a region rich in proline and basic residues (proline-rich region). We searched the bovine adrenal gland for MAP4 isoforms, and identified a novel variant lacking 72 consecutive amino acid residues within the proline-rich region, as compared with the full-length MAP4. The amino acid sequence of the missing region was highly conserved (about 85% identity/similarity) among the corresponding regions of bovine, human, mouse, and rat MAP4, which suggested the functional significance of this region. A comparison of the genomic sequence with the cDNA sequence revealed that the missing region is encoded by a single exon. A MAP4... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628530 Tue, 01 Feb 2005 05:00:00 +0100 1628530 http://www.medworm.com/index.php?rid=1628529&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840944%26dopt%3DAbstract Authors: Yoshida J, Tani T Export of mRNA from the nucleus to the cytoplasm is one of the essential steps for eukaryotic gene expression. In the fission yeast Schizosaccharomyces pombe, heat shock stress at 42 degrees C causes block of mRNA export from the nucleus. We now report that saline and ethanol stresses also inhibit nuclear mRNA export, resulting in accumulation of bulk poly (A)+ RNA, as well as a specific mRNA, in the nucleus. Under stressed conditions, an mRNA export receptor Mex67p relocates to the nucleolus from the nuclear periphery and this relocation is closely correlated with inhibition of mRNA export by the stresses. Pretreatment of cells with a mild saline stress induced thermotolerance in mRNA export in a similar manner seen with mild heat pretreatment and protected ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628529 Tue, 01 Feb 2005 05:00:00 +0100 1628529 http://www.medworm.com/index.php?rid=1628528&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840945%26dopt%3DAbstract Authors: Kamiya T, Saitoh O, Nakata H The direct homo- and heteromeric association between G-protein-coupled receptors (GPCRs), adenosine A2A receptor (A(2A)R) and dopamine D2 receptor (D2R), occurs although little is known about the selectivity of their formation (A(2A)R/A(2A)R vs. A(2A)R/D2R). In order to stimulate the heteromerization of A(2A)R and D2R, we have designed a single-polypeptide-chain heterodimeric A(2A)R/D2R complex by fusing the C-terminus of the A(2A)R via transmembrane (TM) of a type II TM protein with the N-terminus of D2R in tandem. This was successfully expressed on the cell surface as a full-length protein with specific binding to the respective ligands and functional coupling to G-proteins comparable to wild-type receptors, suggesting the possible creation of ph... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628528 Tue, 01 Feb 2005 05:00:00 +0100 1628528 http://www.medworm.com/index.php?rid=1628527&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840946%26dopt%3DAbstract Authors: Permana S, Hisanaga S, Nagatomo Y, Iida J, Hotani H, Itoh TJ MAP4, a ubiquitous heat-stable MAP, is composed of an asymmetric structure common to the heat-stable MAPs, consisting of an N-terminal projection (PJ) domain and a C-terminal microtubule (MT)-binding (MTB) domain. Although the MTB domain has been intensively studied, the role of the PJ domain, which protrudes from MT-wall and does not bind to MTs, remains unclear. We investigated the roles of the PJ domain on the dynamic instability of MTs by dark-field microscopy using various PJ domain deletion constructs of human MAP4 (PJ1, PJ2, Na-MTB and KDM-MTB). There was no obvious difference in the dynamic instability between the wtMAP4 and any fragments at 0.1 microM, the minimum concentration required to stabilize MTs. The... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628527 Tue, 01 Feb 2005 05:00:00 +0100 1628527 http://www.medworm.com/index.php?rid=1628526&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840947%26dopt%3DAbstract Authors: Shirakawa T, Nakamura A, Kohama K, Hirakata M, Ogihara S Annexins are a family of Ca2+/phospholipid-binding proteins that have diverse functions. To understand the function of annexin in Physarum polycephalum, we searched for its binding proteins. Here we demonstrate the presence of two novel annexin-binding proteins. The homology search of partial amino acid sequences of these two proteins identified them as aminoacyl-tRNA synthetases (ARSs). Furthermore, antibody against aminoacyl-tRNA synthetases cross-reacted with one of two proteins. Our results imply the interaction between intracellular membrane dynamics and protein translation system, and may give a clue to understand the mechanism of some myositis diseases, which have been known to produce autoantibodies against ARSs.... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628526 Tue, 01 Feb 2005 05:00:00 +0100 1628526 http://www.medworm.com/index.php?rid=1628525&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15840948%26dopt%3DAbstract In conclusion, protamine induces alterations in the epithelial barrier function of MDCK monolayers that may involve the cytoskeleton and TJ-associated proteins. The various actions of protamine on epithelial function may reflect different degrees of interaction of protamine with the plasma membrane and different intracellular processes triggered by this polycation. PMID: 15840948 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628525 Tue, 01 Feb 2005 05:00:00 +0100 1628525 http://www.medworm.com/index.php?rid=1628524&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15951637%26dopt%3DAbstract Authors: Suzuki T, Koyama Y, Ichikawa H, Tsushima K, Abe K, Hayakawa S, Kuruto-Niwa R, Nozawa R, Isemura M The physiologically active metabolite of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) (DVD), is a potent inducer of cell differentiation in human myeloid leukemia cells. In the present study, we examined changes in gene expression during DVD-induced cell differentiation of promyelocytic HL-60 cells employing a DNA microarray technique. The results identified 7 up-regulated and 9 down-regulated genes with a change greater than 1.5-fold after the DVD-treatment for both 2 and 6 days. Seven of these genes were further examined by reverse transcription-polymerase chain reaction (RT-PCR). The results showed that findings obtained from the DNA microarray analysis and RT-PCR are generall... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628524 Sat, 01 Jan 2005 05:00:00 +0100 1628524 http://www.medworm.com/index.php?rid=1628523&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16145243%26dopt%3DAbstract Authors: Aonuma M, Miyamoto M, Inoue YH, Tamai K, Sakai H, Kamasawa N, Matsukage A Previously we have identified the Drosophila orbit gene whose hypomorphic mutations cause abnormal chromosome segregation (Inoue et al., 2000). The orbit encodes Orbit/Mast, a 165-kDa microtubule-associated protein (MAP) with GTP-binding motifs. Two human homologues of the Orbit/Mast, CLASP1 (hOrbit1) and CLASP2 (hOrbit2) have been identified. Using an antibody to CLASP1/hOrbit1 polypeptide, we confirmed that the polypeptide of about 150 kDa associates with microtubule purified from the porcine brain. Thus, we conjectured that CLASP1 may be a human orthologue of the Drosophila Orbit/Mast, and therefore we named it h (human) Orbit1. We constructed the plasmid for expression of a fusion protein of the puta... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628523 Sat, 01 Jan 2005 05:00:00 +0100 1628523 http://www.medworm.com/index.php?rid=1628522&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16272747%26dopt%3DAbstract Authors: Nakamura T, Kashiwazaki J, Shimoda C The soluble NSF attachment protein 25 (SNAP-25) is a component of the SNARE complex that is essential for regulated exocytosis in diverse cell types. Here, we identified a fission yeast SNAP-25 homologue, SpSec9. The sec9+ gene was essential for vegetative growth. sec9 mRNA was detected in vegetative cells and further increased during sporulation. This increase during sporulation was dependent on Mei4, a meiosis-specific transcription factor. A sporulation-deficient sec9 mutant was isolated by random PCR mutagenesis (sec9-10). The sec9-10 mutant also exhibited temperature sensitivity for growth and cell division was found to arrest before completion of cell separation at restrictive temperatures. In sec9-10 cells, the forespore membrane was... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628522 Sat, 01 Jan 2005 05:00:00 +0100 1628522 http://www.medworm.com/index.php?rid=1628521&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16357441%26dopt%3DAbstract Authors: Fukunaga Y, Liu H, Shimizu M, Komiya S, Kawasuji M, Nagafuchi A F9 teratocarcinoma cells in which beta-catenin and/or plakoglobin genes are knocked-out were generated and investigated in an effort to define the role of beta-catenin and plakoglobin in cell adhesion. Loss of beta-catenin expression only did not affect cadherin-mediated cell adhesion activity. Loss of both beta-catenin and plakoglobin expression, however, severely affected the strong cell adhesion activity of cadherin. In beta-catenin-deficient cells, the amount of plakoglobin associated with E-cadherin dramatically increased. In beta-catenin/plakoglobin-deficient cells, the level of E-cadherin and alpha-catenin markedly decreased. In these cells, E-cadherin formed large aggregates in cytoplasm and membrane local... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628521 Sat, 01 Jan 2005 05:00:00 +0100 1628521 http://www.medworm.com/index.php?rid=1628520&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16357442%26dopt%3DAbstract Authors: Kimura R, Iwamoto R, Mekada E Heparin-binding EGF-like growth factor (HB-EGF), a member of the EGF-family, is thought to be important for keratinocyte functions. HB-EGF is first synthesized as a membrane-anchored form, and its soluble form is released by ectodomain shedding. Here we investigate the role of HB-EGF in epidermal hyperplasia induced by all-trans retinoic acid (tRA) treatment. HB-EGF is normally expressed in epidermis of normal adult mice at very low levels, but topical tRA treatment results in epidermal hyperplasia, concomitant with the strong induction of HB-EGF expression in the suprabasal layer. tRA-induced epidermal hyperplasia was reduced both in the keratinocyte-specific HB-EGF null mice (K5-HB(del/del)) and knock-in mice expressing the uncleavable mutant fo... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628520 Sat, 01 Jan 2005 05:00:00 +0100 1628520 http://www.medworm.com/index.php?rid=1628519&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16357443%26dopt%3DAbstract Authors: Kashiwazaki J, Nakamura T, Iwaki T, Takegawa K, Shimoda C Ypt7p, a fission yeast (Schizosaccharomyces pombe) homologue of Rab7 GTPase, mediates fusion of endosomes to vacuoles and homotypic vacuole fusion. Here, we report that Ypt7p plays important roles in sporulation. Most ypt7Delta asci produced less than four spores, which were apparently immature and germinated at low frequency. Furthermore, ypt7Delta cells were defective in development of the forespore membranes. Vacuoles in sporulating cells were found to undergo extensive homotypic vacuole fusion to form a few large compartments occupying the entire cytoplasm of asci. This extensive vacuole fusion depended on Ypt7p. PMID: 16357443 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628519 Sat, 01 Jan 2005 05:00:00 +0100 1628519 http://www.medworm.com/index.php?rid=1628518&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16377940%26dopt%3DAbstract Authors: Miki T, Takano K, Yoneda Y The localization of mRNA in neuronal dendrites plays a role in both locally and temporally regulated protein synthesis, which is required for certain forms of synaptic plasticity. RNA granules constitute a dendritic mRNA transport machinery in neurons, which move along microtubules. RNA granules contain densely packed clusters of ribosomes, but lack some factors that are required for translation, suggesting that they are translationally incompetent. Recently some of the components of RNA granules have been identified, and their functions are in the process of being examined, in attempts to better understand the properties of RNA granules. Mammalian Staufen, a double-stranded RNA binding protein, is a component of RNA granules. Staufen is localized in... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628518 Sat, 01 Jan 2005 05:00:00 +0100 1628518 http://www.medworm.com/index.php?rid=1628517&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16415535%26dopt%3DAbstract Authors: Igarashi R, Suzuki M, Nogami S, Ohya Y The dynactin complex is one of the components required for the regulation of the cell wall integrity checkpoint, which ensures the completion of cell wall remodeling before mitosis. The core of the dynactin complex is a backbone filament composed of monomers of an actin-related protein, Arp1, which is also involved in nuclear migration. To examine the molecular basis for the dual functions of the dynactin core subunit Arp1p in yeast, we constructed 32 mutated arp1 alleles. We assessed the effects of the mutations on cell wall integrity checkpoint and nuclear migration functions and identified four categories of mutants: 1) those showing no change from the wild type; 2) those resulting in a defective cell wall integrity checkpoint but norm... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628517 Sat, 01 Jan 2005 05:00:00 +0100 1628517 http://www.medworm.com/index.php?rid=1628516&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16428860%26dopt%3DAbstract Authors: Takeda E, Hieda M, Katahira J, Yoneda Y Ran is a nuclear Ras-like GTPase that is required for various nuclear events including the bi-directional transport of proteins and ribonucleoproteins through the nuclear pore complex, spindle formation, and reassembly of the nuclear envelope. One of the key regulators of Ran is RanGAP1, a Ran specific GTPase activating protein. The question of whether a mechanism exists for controlling nucleocytoplasmic transport through the regulation of RanGAP1 activity continues to be debated. Here we show that RanGAP1 is phosphorylated in vivo and in vitro. Serine-358 (358S) was identified as the major phosphorylation site, by MALDI-TOF-MS spectrometry. Site directed mutagenesis at this position abolished the phosphorylation. Experiments using purif... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628516 Sat, 01 Jan 2005 05:00:00 +0100 1628516 http://www.medworm.com/index.php?rid=1628515&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16428861%26dopt%3DAbstract Authors: Tsuda K, Amano A, Umebayashi K, Inaba H, Nakagawa I, Nakanishi Y, Yoshimori T Porphyromonas gingivalis is one of the causative agents of adult periodontitis, and has been reported to be internalized by nonphagocytic epithelial cells. However, the mechanism for the internalization remains unclear. In the present study, we addressed this issue using fluorescent beads coated with bacterial membrane vesicles (MVs) that retain surface components of P. gingivalis. We established an assay system in which we could easily quantify the bead internalization to cells. MVs-coated beads were internalized by HeLa cells in kinetics similar to that of living bacteria. The internalization depended on dynamin but not clathrin. The beads were internalized through the actin-mediated pathway that i... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628515 Sat, 01 Jan 2005 05:00:00 +0100 1628515 http://www.medworm.com/index.php?rid=1628514&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16474191%26dopt%3DAbstract Authors: Shiba D, Takamatsu T, Yokoyama T Primary cilia are hypothesized to act as a mechanical sensor to detect renal tubular fluid flow. Anomalous structure of primary cilia and/or impairment of increases in intracellular Ca2+ concentration in response to fluid flow are thought to result in renal cyst formation in conditional kif3a knockout, Tg737 and pkd1/pkd2 mutant mice. The mutant inv/inv mouse develops multiple renal cysts like kif3a, Tg737 and pkd1/pkd2 mutants. Inv proteins have been shown to be localized in the renal primary cilia, but response of inv/inv cilia to fluid stress has not been examined. In the present study, we examined the mechanical response of primary cilia to physiological fluid flow using a video microscope, as well as intracellular Ca2+ increases in renal e... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628514 Sat, 01 Jan 2005 05:00:00 +0100 1628514 http://www.medworm.com/index.php?rid=1628533&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15665503%26dopt%3DAbstract Authors: Nishihara E, Shimmen T, Sonobe S Contractile vacuoles (CVs) released from cells of Amoeba proteus were used to analyze its function in vitro. When CV was transferred to a hypertonic medium, its volume decreased within 10 sec. When it was subsequently returned to its original medium, it quickly started swelling. However, it ruptured before recovering its initial volume. These results suggested that the CV membrane is semi-permeable and that the fluid is collected by the osmotic gradient in vivo. The water permeability of membrane of isolated CV was calculated from the rate of osmotic volume change to be 0.94 microm/sec . OsM. This high value suggested that CV membrane is equipped with water channel. CV contracted (or burst) quickly upon addition of 1 mM ATP. Contraction was ind... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628533 Wed, 01 Dec 2004 05:00:00 +0100 1628533 http://www.medworm.com/index.php?rid=1628532&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15665504%26dopt%3DAbstract Authors: Li SA, Watanabe M, Yamada H, Nagai A, Kinuta M, Takei K Klotho mutant mouse (kl-/-), a mouse model for human aging, exhibits various phenotypes in a wide range of organs including arteriosclerosis, neural degeneration, skin and gonadal atrophy, pulmonary emphysema, calcification of soft tissues, and cognition impairment. Klotho mRNA, however, is expressed only in brain, kidney, reproductive organs, pituitary gland, and parathyroid gland. Therefore it remains to be elucidated how lack of Klotho protein in these limited organs leads to the variety of phenotypes. To shed light on mechanisms by which Klotho protein acts on distant targets, we examined localization of Klotho protein in brain, kidney, and reproductive organs, and analyzed brain and kidney in kl-/- mice searching for... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628532 Wed, 01 Dec 2004 05:00:00 +0100 1628532 http://www.medworm.com/index.php?rid=1628531&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15665505%26dopt%3DAbstract In this study, we found that treatment of PC12 cells with the A(2A)-R agonist CGS21680 promotes calcium-evoked secretion of the fusion protein between neuropeptide Y and modified yellow fluorescence protein (NPY-Venus). CGS21680 treatment of PC12 cells transiently increased the phosphorylation of p38 and JNK MAP kinases and Akt, as well as that of ATF2 and CREB, reaching maximal levels at around 10-15 min of CGS21680 treatment. Importantly, pretreatment of PC12 cells with the PI3K inhibitor LY294002, together with the protein kinase A (PKA) inhibitor KT5720, significantly inhibited CGS21680 enhancement of calcium-dependent NPY-Venus release. Moreover, expression of a dominant-negative form of Akt and the PKA inhibitory polypeptide protein kinase inhibitor (PKI) co-operatively inhibited the... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628531 Wed, 01 Dec 2004 05:00:00 +0100 1628531 http://www.medworm.com/index.php?rid=1628535&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15528838%26dopt%3DAbstract Authors: Watanabe Y, Hayashi M, Yagi T, Kamiya R Recent indirect observations have suggested that various axonemal proteins in cilia and flagella of live cells undergo turnover independently of shortening or elongation of the axoneme. To gain direct evidence, here we examined using a FRAP (fluorescence recovery after photobleaching) technique whether actin, a subunit of inner arm dynein, is being turned over in Chlamydomonas flagella. Fluorescently labeled rabbit actin was introduced by electroporation into the cells of ida5oda1, a double mutant between oda1 lacking outer arm dynein and ida5 lacking several species of inner arm dyneins due to the absence of a conventional-type actin. In actin-loaded cells, flagella became motile and fluorescent due to incorporation of inner-arm dyneins... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628535 Tue, 01 Jun 2004 04:00:00 +0100 1628535 http://www.medworm.com/index.php?rid=1628534&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15528839%26dopt%3DAbstract Authors: Takashima S, Ise H, Zhao P, Akaike T, Nikaido T Hepatocyte transplantation is expected to become a novel method for treatment of liver disease. However, many questions remain regarding this approach, especially concerning donor cells. To evaluate whether human amniotic epithelial cells can be used as a cell source for hepatocyte transplantation, hepatic gene expression and functions of human amniotic epithelial cells were analyzed. Reverse transcription-polymerase chain reaction analysis demonstrated that human amniotic epithelial cells expressed albumin, alpha(1)-antitrypsin, and other hepatocyte-related genes. Cultivated human amniotic epithelial cells demonstrated albumin production, glycogen storage, and albumin secretion consistent with the hepatocyte gene expression prof... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628534 Tue, 01 Jun 2004 04:00:00 +0100 1628534 http://www.medworm.com/index.php?rid=1628564&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15185676%26dopt%3DAbstract Authors: PMID: 15185676 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628564 Sat, 01 May 2004 04:00:00 +0100 1628564 http://www.medworm.com/index.php?rid=1628539&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15342962%26dopt%3DAbstract In conclusion, our morphological and biochemical data clearly showed that in vivo stimulation with CAR induces a potent inflammatory response in macrophages representing an interesting model to analyze inflammatory responses. PMID: 15342962 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628539 Thu, 01 Apr 2004 05:00:00 +0100 1628539 http://www.medworm.com/index.php?rid=1628538&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15342963%26dopt%3DAbstract Authors: Chen GY, Muramatsu H, Ichihara-Tanaka K, Muramatsu T We isolated a mouse cDNA encoding a protein that contains a BEACH domain, 5 WD40 repeats and a FYVE domain, which we designated as BWF1. The mRNA is approximately 10 kb in size and encodes a protein consisting of 3508 amino acids with a predicted molecular weight of 385 kDa. BWF1 has 45% homology with the Drosophila protein, blue cheese (BCHS). The BWF1 gene consists of 67 exons, which span 270 kb of genomic sequence, and has been mapped to mouse chromosome 5. Northern blot analysis revealed that it was strongly expressed in the liver, moderately in the kidney and testis, and weakly in the brain of adult mice. During the development of the mouse brain, BWF1 mRNA was abundant on embryonic day (E) 14-16; after birth, the level... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628538 Thu, 01 Apr 2004 05:00:00 +0100 1628538 http://www.medworm.com/index.php?rid=1628537&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15342964%26dopt%3DAbstract An ultrastructural and biochemical study of foot structure in "catch" smooth muscle cells of a clam. Cell Struct Funct. 2004 Apr;29(2):43-8 Authors: Notsu E, Matsuno A The foot structure of molluscan (clam) catch muscle cells was studied from the structural and biochemical standpoints. In vertebrate cross striated muscle cells, foot structures are situated in the interspaces between T-tubules and sarcoplasmic reticula (SRs). By contrast, T-tubules were not observed in clam catch muscle cells, but foot structures were ultrastructurally identified in the interspaces between the SRs and cell membranes. We isolated the SR fraction from muscle cells which contained vesicles with SRs and cell membranes. Foot structures were also observed in the SR fraction by thin sectioning. The siz... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628537 Thu, 01 Apr 2004 05:00:00 +0100 1628537 http://www.medworm.com/index.php?rid=1628536&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15342965%26dopt%3DAbstract Authors: Uemura T, Ueda T, Ohniwa RL, Nakano A, Takeyasu K, Sato MH In all eucaryotic cells, specific vesicle fusion during vesicular transport is mediated by membrane-associated proteins called SNAREs (soluble N-ethyl-maleimide sensitive factor attachment protein receptors). Sequence analysis identified a total of 54 SNARE genes (18 Qa-SNAREs/Syntaxins, 11 Qb-SNAREs, 8 Qc-SNAREs, 14 R-SNAREs/VAMPs and 3 SNAP-25) in the Arabidopsis genome. Almost all of them were ubiquitously expressed through out all tissues examined. A series of transient expression assays using green fluorescent protein (GFP) fused proteins revealed that most of the SNARE proteins were located on specific intracellular compartments: 6 in the endoplasmic reticulum, 9 in the Golgi apparatus, 4 in the trans-Golgi netwo... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628536 Thu, 01 Apr 2004 05:00:00 +0100 1628536 http://www.medworm.com/index.php?rid=1628566&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15107529%26dopt%3DAbstract Authors: Iwase M, Toh-e A YBR267w designated REI1 (required for isotropic bud growth) was isolated by two-hybrid screening using NIS1 encoding the neck protein as bait. Disruption of REI1 exhibited cold sensitive growth but did not exhibit a morphological defect. However, Deltarei1Deltanap1, Deltarei1Deltacla4 and Deltarei1Deltagin4 double disruptants exhibited an elongated cell morphology, which was suppressed by the disruption of SWE1, indicating that REI1 is a new member of genes belonging to the mitotic signaling network that negatively regulates Swe1 kinase. Deltanap1 cells displayed a lower Gin4 kinase activity and a lower Gin4 protein level, both of which were recovered nearly to a wild type level in Deltarei1Deltanap1 cells. Interaction between Rei1 and Gin4 was suggested from ... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628566 Sun, 01 Feb 2004 05:00:00 +0100 1628566 http://www.medworm.com/index.php?rid=1628565&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15107530%26dopt%3DAbstract Authors: Ohga R, Shida M, Shida H Here we report a new method of isolating epidermal desmosomes from Xenopus laevis, and a major constituent of desmosomes designated as Xenopus desmogleins (XDsg). Isolation of desmosomes from Xenopus laevis epidermis was carried out by a two step-incubation with different concentrations of NP-40. After discontinuous sucrose gradient centrifugation at 30,000 g for 60 min, a pure desmosomal fraction was obtained at 30%/40% interface. In the SDS-PAGE of isolated desmosomes, at least 12 bands (XDB1 to XDB12) were observed over a 75 kD region. Among them, three bands (XDB3, XDB7, XDB8; estimated MW 175, 124, and 112 kD respectively) were recognized as glycoproteins based on ConA binding. Monospecific polyclonal antibody against XDB3 cross-reacted with bovin... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628565 Sun, 01 Feb 2004 05:00:00 +0100 1628565 http://www.medworm.com/index.php?rid=1628568&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15004420%26dopt%3DAbstract We examined the regulatory role of the native form of type I collagen fibrils in pro-MMP-2 production and activation in cultured HSCs. Gelatin zymography of the conditioned media revealed that pro- and active form of MMP-2 was increased in the HSCs cultured on type I collagen gel but not on type I collagen-coated surface, gelatin-coated surface, type IV collagen-coated surface, or Matrigel, suggesting the importance of the native form of type I collagen fibrils in pro-MMP-2 production and activation. The induction of active MMP-2 by extracellular type I collagen was suppressed by the blocking antibody against integrin beta1 subunits, indicating the involvement of integrin signaling in pro-MMP-2 activation. RT-PCR analysis indicated that MMP-2, membrane type-1 MMP (MT1-MMP) and tissue inhib... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628568 Mon, 01 Dec 2003 05:00:00 +0100 1628568 http://www.medworm.com/index.php?rid=1628567&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15004421%26dopt%3DAbstract Authors: Tanaka T, Ono T, Kitamura N, Kato JY The cleavage cycle, which is initiated by fertilization, consists of only S and M phases, and the gap phases (G1 and G2) appear after the midblastula transition (MBT) in the African clawed frog, Xenopus laevis. During early development in Xenopus, we examined the E2F activity, which controls transition from the G1 to S phase in the somatic cell cycle. Gel retardation and transactivation assays revealed that, although the E2F protein was constantly present throughout early development, the E2F transactivation activity was induced in a stage-specific manner, that is, low before MBT and rapidly increased after MBT. Introduction of the recombinant dominant negative E2F (dnE2F), but not the control, protein into the 2-cell stage embryos specific... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628567 Mon, 01 Dec 2003 05:00:00 +0100 1628567 http://www.medworm.com/index.php?rid=1628563&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216878%26dopt%3DAbstract We examined the structural rearrangements of the actin cytoskeleton during the microbial infection process. Macrophage actin filaments were rearranged in the following sequence; 1) disappearance of the actin filament bundles in the cytoplasm, 2) accumulation of actin filaments under the cell surface, and 3) construction of actin networks underlying the endosome membrane. Before infection, actin filaments were distributed under the cell surface and in bundles located in the macrophage cytoplasm. Within 2 min, infection caused a rapid and marked loss of the actin filament bundles that had run parallel to the long axis of the cell. Concomitant with the loss, actin filaments became more markedly distributed under the cell surface. In the formation of the endosome, new networks of actin filamen... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628563 Fri, 01 Oct 1999 04:00:00 +0100 1628563 http://www.medworm.com/index.php?rid=1628562&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216879%26dopt%3DAbstract This study examined whether macrophages are involved in the development of pathogenicity in Shiga-like toxin (SLT)-producing enterohemorrhagic Escherichia coil (EHEC) O157:H7. Macrophages were infected with the bacteria, after which the macrophage culture medium showed a clear increase in toxicity in rats in vivo as well as in rat aortic endothelial cells in vitro. The increased toxicity resulted mainly from a rapid increase in the concentrations of SLT type I (SLT-I) and type II (SLT-II) and partly from an increase in concentrations of the proinflammatory cytokines, tumor necrosis factor alpha (TNFalpha) and interleukin-1 (IL-1), in the culture medium. Most of the EHEC O157 added to the macrophage culture were quickly incorporated to form phagosomes, which then fused with lysosomes to bec... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628562 Fri, 01 Oct 1999 04:00:00 +0100 1628562 http://www.medworm.com/index.php?rid=1628561&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216880%26dopt%3DAbstract In this study, we have assessed the effects of several types of substrata on the expression of MMPs in HSC culture. MMP-1 expression was detectable in HSC culture on polystyrene surface and on type I collagen gel by immunofluorescence staining and reverse transcriptase-polymerase chain reaction (RT-PCR). The results from in situ zymography revealed the presence of interstitial collagenase activity around HSCs and along their cellular processes. Although proMMP-2 and proMMP-9 were detectable by gelatin zymography in the conditioned medium from both cultures using type I collagen gel and Matrigel as substratum, an active form of MMP-2 but not of MMP-9 was detected only in the culture using type I collagen as a substratum. Tissue inhibitor of metalloproteinase-2 expression was observed by RT-... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628561 Fri, 01 Oct 1999 04:00:00 +0100 1628561 http://www.medworm.com/index.php?rid=1628560&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216881%26dopt%3DAbstract Authors: PMID: 15216881 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628560 Fri, 01 Oct 1999 04:00:00 +0100 1628560 http://www.medworm.com/index.php?rid=1628559&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216882%26dopt%3DAbstract Authors: Downing KH, Nogales E The structure of tubulin, recently solved by electron crystallography, has given a first look at the molecular basis for some of the properties of tubulin and microtubules that have been observed over the last decades. We discuss how the structure relates to some of these properties, and how inferences about drug binding sites can explain some of the effects of the drugs on tubulin. Microtubules can form a highly dynamic system that requires careful tuning of the stability and properties of tubulin and its interactions with its many ligands. Understanding these interactions can provide fundamental information on the regulation of the microtubule system. PMID: 15216882 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628559 Fri, 01 Oct 1999 04:00:00 +0100 1628559 http://www.medworm.com/index.php?rid=1628558&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216883%26dopt%3DAbstract Authors: Hirose K, Löwe J, Alonso M, Cross RA, Amos LA We have studied the structure of microtubules decorated with kinesin motor domains in different nucleotide states by 3D electron microscopy. Having docked the atomic coordinates of both dimeric ADP.kinesin and tubulin heterodimer into a map of kinesin dimers bound to microtubules in the presence of ADP, we try to predict which regions of the proteins interact in the weakly binding state. When either the presence of 5'-adenylyimidodiphosphate (AMP-PNP) or an absence of nucleotides puts motor domains into a strongly-bound state, the 3D maps show changes in the motor domains which modify their interaction with beta-tubulin. The maps also show differences in beta-tubulin conformation compared with undecorated microtubules or those... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628558 Fri, 01 Oct 1999 04:00:00 +0100 1628558 http://www.medworm.com/index.php?rid=1628557&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216884%26dopt%3DAbstract Authors: Lu C, Erickson HP Bacterial cell division protein FtsZ assembles into protofilaments, which can adopt a straight or curved conformation, similar to its eukaryotic homolog, tubulin. The straight protofilaments can assemble into sheets with a lattice similar to the microtubule wall. The curved protofilaments can form rings when adsorbed to a lipid monolayer, but in solution they form helices. 4 helices assemble together to make a tube, the characteristic polymer of the curved protofilament. GTP favors the straight conformation, while GDP favors the curved. We show here that addition of EDTA and GTP to tubes causes a rapid transformation to straight protofilament sheets. Apparently when the magnesium is chelated the GDP in the curved protofilaments dissociates rapidly and is repl... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628557 Fri, 01 Oct 1999 04:00:00 +0100 1628557 http://www.medworm.com/index.php?rid=1628556&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216885%26dopt%3DAbstract Authors: Haraguchi T, Ding DQ, Yamamoto A, Kaneda T, Koujin T, Hiraoka Y Microscopic observation of fluorescently-stained intracellular molecules within a living cell provides a straightforward approach to understanding their temporal and spatial relationships. However, exposure to the excitation light used to visualize these fluorescently-stained molecules can be toxic to the cells. Here we describe several important considerations in microscope instrumentation and experimental conditions for avoiding the toxicity associated with observing living fluorescently-stained cells. Using a computer-controlled fluorescence microscope system designed for live observation, we recorded time-lapse, multi-color images of chromosomes and microtubules in living human and fission yeast cells. In HeLa... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628556 Fri, 01 Oct 1999 04:00:00 +0100 1628556 http://www.medworm.com/index.php?rid=1628555&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216886%26dopt%3DAbstract Authors: Chrétien D, Jáinosi I, Taveau JC, Flyvbjerg H The molecular mechanisms that allow elongation of the unstable microtubule lattice remain unclear. It is usually thought that the GDP-liganded tubulin lattice is capped by a small layer of GTP- or GDP-Pi-liganded molecules, the so called "GTP-cap". Here, we point-out that the elastic properties of the microtubule lattice cause a difference in stability between the elongating tubulin sheet and the completed microtubule wall. The implications of our observations for microtubule structure and dynamics are discussed. PMID: 15216886 [PubMed - indexed for MEDLINE] (Source: Cell Structure and Function) Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628555 Fri, 01 Oct 1999 04:00:00 +0100 1628555 http://www.medworm.com/index.php?rid=1628554&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216887%26dopt%3DAbstract Authors: Muraoka M, Sakai H This minireview summarizes the syntheses of various purinenucleotide analogues and their effects on microtubule (Mt) assembly. 27 analogues were so far synthesized and, together with 3 analogues commercially available (ITP, XTP and dGTP), their effects on Microtubule assembly were investigated. The positions C2, C6, C8, and ribose moiety of purine nucleotides were modified or substituted. It was found that the microenvironments of the purine base and ribose moiety are important for the nucleotides to support Mt assembly. Introduction of amino group into position C2 of ATP, formation of 2-amino ATP, caused Mt assembly substantially. 2-Amino deoxy ATP and deoxy GTP are more potent than GTP in supporting assembly. The introduction of reactive thiol group into C... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628554 Fri, 01 Oct 1999 04:00:00 +0100 1628554 http://www.medworm.com/index.php?rid=1628553&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216888%26dopt%3DAbstract Authors: Bulinski JC, Gruber D, Faire K, Prasad P, Chang W E-MAP-115 (ensconsin) is a microtubule-associated protein (MAP) abundant in carcinoma and other epithelia-derived cells. We expressed chimeras of green fluorescent protein (GFP) conjugated to ensconsin's N-terminal MT-binding domain (EMTB), to study distribution, dynamics, and function of the MAP in living cells. We tested the hypothesis that behavior of expressed GFP-EMTB accurately matched behavior of endogenous ensconsin. Like endogenous MAP, GFP-EMTB was associated with microtubules in living or fixed cells, and microtubule association of either molecule was impervious to extraction with nonionic detergents. In cell lysates both GFP-EMTB and endogenous ensconsin were dissociated from microtubules by identical salt extractio... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628553 Fri, 01 Oct 1999 04:00:00 +0100 1628553 http://www.medworm.com/index.php?rid=1628552&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216889%26dopt%3DAbstract Authors: Srsen V, Kitazawa H, Sugita M, Murofushi H, Bulinski JC, Kishimoto T, Hisanaga S In the previous paper (Ookata et al., (1997) Biochemistry, 36: 249-259), we identified two mitotic cdc2 kinase phosphorylation sites (Ser696 and Ser787) in the proline-rich region of human MAP4. One (Ser696) of them was also phosphorylated during interphase. A protein kinase responsible for interphase phosphorylation of Ser696 could necessarily be distinct from cdc2/cyclin B kinase. To get insights into a physiological role for Ser696 phosphorylation, we searched for a Ser696 kinase and for cellular conditions under which Ser696 is dephosphorylated. Because Ser696 conforms to the MAP kinase phosphorylation consensus motif (PXSP), MAP kinase was tested as a possible kinase phosphorylating Ser696. M... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628552 Fri, 01 Oct 1999 04:00:00 +0100 1628552 http://www.medworm.com/index.php?rid=1628551&cid=s_37763_171_f&fid=37763&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15216890%26dopt%3DAbstract Authors: Wilson L, Panda D, Jordan MA Microtubules are intrinsically dynamic polymers. Two kinds of dynamic behaviors, dynamic instability and treadmilling, are important for microtubule function in cells. Both dynamic behaviors appear to be tightly regulated, but the cellular molecules and the mechanisms responsible for the regulation remain largely unexplored. While microtubule dynamics can be modulated transiently by the interaction of regulatory molecules with soluble tubulin, the microtubule itself is likely to be the primary target of cellular molecules that regulate microtubule dynamics. The antimitotic drugs that modulate microtubule dynamics serve as excellent models for such cellular molecules. Our laboratory has been investigating the interactions of small drug molecules and... Cell Structure and Function journals http://www.medworm.com/rss/comments.php?id=1628551 Fri, 01 Oct 1999 04:00:00 +0100 1628551