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122 records returned

Spermidine regulates insulin synthesis and cytoplasmic Ca(2+) in mouse beta-TC6 insulinoma cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 polya...
Source: Cell Structure and Function - November 2, 2009 Category: Cytology Authors: Ohtani M, Mizuno I, Kojima Y, Ishikawa Y, Sodeno M, Asakura Y, Samejima K, Oka T Tags: Cell Struct Funct Source Type: journals

Role of VAMP8/endobrevin in Constitutive Exocytotic Pathway in HeLa Cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Cell Structure and Function - September 7, 2009 Category: Cytology Authors: Okayama M, Arakawa T, Tanimura A, Mizoguchi I, Tajima Y, Takuma T Tags: Cell Struct Funct Source Type: journals

Increased motility and invasiveness in tumor cells that survive 10 gy irradiation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - September 3, 2009 Category: Cytology Authors: Tsutsumi K, Tsuda M, Yazawa N, Nakamura H, Ishihara S, Haga H, Yasuda M, Yamazaki R, Shirato H, Kawaguchi H, Nishioka T, Ohba Y Tags: Cell Struct Funct Source Type: journals

Expression of Prolyl 3-hydroxylase Genes in Embryonic and Adult Mouse Tissues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - July 31, 2009 Category: Cytology Authors: Vranka J, Stadler HS, Bächinger HP Tags: Cell Struct Funct Source Type: journals

Ectopic Calcification is Caused by Elevated Levels of Serum Inorganic Phosphate in Mdx Mice.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - July 17, 2009 Category: Cytology Authors: Kikkawa N, Ohno T, Nagata Y, Shiozuka M, Kogure T, Matsuda R Tags: Cell Struct Funct Source Type: journals

Male germline stem cell division and spermatocyte growth require insulin signaling in Drosophila.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - June 27, 2009 Category: Cytology Authors: Ueishi S, Shimizu H, H Inoue Y Tags: Cell Struct Funct Source Type: journals

The RZZ complex and the spindle assembly checkpoint.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 assem...
Source: Cell Structure and Function - June 27, 2009 Category: Cytology Authors: Lu Y, Wang Z, Ge L, Chen N, Liu H Tags: Cell Struct Funct Source Type: journals

TRFH Domain Is Critical for TRF1-Mediated Telomere Stabilization.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - June 10, 2009 Category: Cytology Authors: Okamoto K, Shinkai Y Tags: Cell Struct Funct Source Type: journals

Simultaneous Single Cell Stable Expression of 2-4 cDNAs in HeLaS3 Using psiC31 Integrase System.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 integratio...
Source: Cell Structure and Function - March 20, 2009 Category: Cytology Authors: Nishiumi F, Sone T, Kishine H, Thyagarajan B, Kogure T, Miyawaki A, Chesnut JD, Imamoto F Tags: Cell Struct Funct Source Type: journals

Magnetic Separation of Human Podocalyxin-like Protein 1 (hPCLP1)-Positive Cells from Peripheral Blood and Umbilical Cord Blood Using Anti-hPCLP1 Monoclonal Antibody and Protein A Expressed on Bacterial Magnetic Particles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 th...
Source: Cell Structure and Function - March 17, 2009 Category: Cytology Authors: Kuhara M, Yoshino T, Shiokawa M, Okabe T, Mizoguchi S, Yabuhara A, Takeyama H, Matsunaga T Tags: Cell Struct Funct Source Type: journals

Novel Function of Transcription Factor ATF5: Blockade of p53-dependent Apoptosis Induced by Ionizing Irradiation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - March 17, 2009 Category: Cytology Authors: Nishioka T, Miyai Y, Haga H, Kawabata K, Shirato H, Shibata K, Yasuda M Tags: Cell Struct Funct Source Type: journals

Insufficient Membrane Fusion in Dysferlin-Deficient Muscle Fibers after Heavy-Ion Irradiation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 plas...
Source: Cell Structure and Function - February 13, 2009 Category: Cytology Authors: Hino M, Hamada N, Tajika Y, Funayama T, Morimura Y, Sakashita T, Yokota Y, Fukamoto K, Kobayashi Y, Yorifuji H Tags: Cell Struct Funct Source Type: journals

pXBP1(U), a Negative Regulator of the Unfolded Protein Response Activator pXBP1(S), Targets ATF6 but not ATF4 in Proteasome-mediated Degradation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - January 1, 2009 Category: Cytology Authors: Yoshida H, Uemura A, Mori K Tags: Cell Struct Funct Source Type: journals

Mature Adipocyte-Derived Dedifferentiated Fat Cells Can Trans-Differentiate into Osteoblasts In Vitro and In Vivo only by All-Trans Retinoic Acid.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 matri...
Source: Cell Structure and Function - December 17, 2008 Category: Cytology Authors: Oki Y, Watanabe S, Endo T, Kano K Tags: Cell Struct Funct Source Type: journals

Mechanical Strain Increases Expression of Type XII Collagen in Murine Osteoblastic MC3T3-E1 Cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 imp...
Source: Cell Structure and Function - October 29, 2008 Category: Cytology Authors: Arai K, Nagashima Y, Takemoto T, Nishiyama T Tags: Cell Struct Funct Source Type: journals

Suppression of Cardiac Troponin T Induces Reduction of Contractility and Structural Disorganization in Chicken Cardiomyocytes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 consecu...
Source: Cell Structure and Function - October 24, 2008 Category: Cytology Authors: Toyota N, Takano-Ohmuro H, Yoshida LS, Araki M, Yoshinobu K, Suzuki-Toyota F Tags: Cell Struct Funct Source Type: journals

Cross-talk-free Fluorescence Cross-Correlation Spectroscopy by the Switching Method.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 - October 22, 2008 Category: Cytology Authors: Takahashi Y, Nishimura J, Suzuki A, Ishibashi K, Kinjo M, Miyawaki A Tags: Cell Struct Funct Source Type: journals

Migratory Localization of Cyclin D2-Cdk4 Complex Suggests a Spatial Regulation of the G1-S Transition.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - October 1, 2008 Category: Cytology Authors: Wang Z, Xie Y, Zhang L, Zhang H, An X, Wang T, Meng A Tags: Cell Struct Funct Source Type: journals

SYP71, a Plant-specific Qc-SNARE Protein, Reveals Dual Localization to the Plasma Membrane and the Endoplasmic Reticulum in Arabidopsis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Cell Structure and Function - October 1, 2008 Category: Cytology Authors: Suwastika IN, Uemura T, Shiina T, Sato MH, Takeyasu K Tags: Cell Struct Funct Source Type: journals

MicroRNA-206 Is Highly Expressed in Newly Formed Muscle Fibers: Implications Regarding Potential for Muscle Regeneration and Maturation in Muscular Dystrophy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 a...
Source: Cell Structure and Function - October 1, 2008 Category: Cytology Authors: Yuasa K, Hagiwara Y, Ando M, Nakamura A, Takeda S, Hijikata T Tags: Cell Struct Funct Source Type: journals

Involvement of a 25 kDa Tetrahymena Ca(2+)-binding Protein in Pronuclear Exchange.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 de...
Source: Cell Structure and Function - September 5, 2008 Category: Cytology Authors: Nakagawa T, Fujiu K, Cole ES, Numata O Tags: Cell Struct Funct Source Type: journals

A Mercury Arc Lamp-Based Multi-Color Confocal Real Time Imaging System for Cellular Structure and Function.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 scramb...
Source: Cell Structure and Function - August 6, 2008 Category: Cytology Authors: Saito K, Kobayashi K, Tani T, Nagai T Tags: Cell Struct Funct Source Type: journals

The organization of histone H3 modifications as revealed by a panel of specific monoclonal antibodies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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-...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Kimura H, Hayashi-Takanaka Y, Goto Y, Takizawa N, Nozaki N Tags: Cell Struct Funct Source Type: journals

Human RME-8 is involved in membrane trafficking through early endosomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 mark...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology 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 Tags: Cell Struct Funct Source Type: journals

GFP-like proteins stably accumulate in lysosomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Katayama H, Yamamoto A, Mizushima N, Yoshimori T, Miyawaki A Tags: Cell Struct Funct Source Type: journals

BDNF increases the phagocytic activity in cultured iris pigment epithelial cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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-k...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Yoshida H, Tomita H, Sugano E, Isago H, Ishiguro S, Tamai M Tags: Cell Struct Funct Source Type: journals

Different effects of all-trans-retinoic acid on phorbol ester-stimulated and phytohemagglutinin-stimulated interleukin-2 expression in human T-cell lymphoma HUT-78 cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 rea...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Goto S, Okada N, Kaneko A, Isemura M Tags: Cell Struct Funct Source Type: journals

Phospholipase D is essential for keratocyte-like migration of NBT-II cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Nagasaki A, Inotsume K, Kanada M, Uyeda TQ Tags: Cell Struct Funct Source Type: journals

ATF6 is a transcription factor specializing in the regulation of quality control proteins in the endoplasmic reticulum.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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. B...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Adachi Y, Yamamoto K, Okada T, Yoshida H, Harada A, Mori K Tags: Cell Struct Funct Source Type: journals

Mechanism of destruction of microtubule structures by 4-hydroxy-2-nonenal.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Kokubo J, Nagatani N, Hiroki K, Kuroiwa K, Watanabe N, Arai T Tags: Cell Struct Funct Source Type: journals

Recruitment of Tom1L1/Srcasm to endosomes and the midbody by Tsg101.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Yanagida-Ishizaki Y, Takei T, Ishizaki R, Imakagura H, Takahashi S, Shin HW, Katoh Y, Nakayama K Tags: Cell Struct Funct Source Type: journals

Dynein-dependent movement of autophagosomes mediates efficient encounters with lysosomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 fo...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Kimura S, Noda T, Yoshimori T Tags: Cell Struct Funct Source Type: journals

Ultrastructural study of Rac1 and its effectors beneath the substratum-facing membrane.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - July 16, 2008 Category: Cytology Authors: Watanabe T, Wang S, Kakeno M, Usukura J, Kaibuchi K Tags: Cell Struct Funct Source Type: journals

Functional Analysis of alpha5beta1 Integrin and Lipid Rafts in Invasion of Epithelial Cells by Porphyromonas gingivalis using Fluorescent Beads Coated with Bacterial Membrane Vesicle.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - April 4, 2008 Category: Cytology Authors: Tsuda K, Furuta N, Inaba H, Kawai S, Hanada K, Yoshimori T, Amano A Tags: Cell Struct Funct Source Type: journals

AMSH, an ESCRT-III associated enzyme, deubiquitinates cargo on MVB/late endosomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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. Nevert...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Kyuuma M, Kikuchi K, Kojima K, Sugawara Y, Sato M, Mano N, Goto J, Takeshita T, Yamamoto A, Sugamura K, Tanaka N Tags: Cell Struct Funct Source Type: journals

Substitution F659G in the Irr1p/Scc3p cohesin influences the cell wall of Saccharomyces cerevisiae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 th...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Cena A, Orlowski J, Machula K, Fronk J, Kurlandzka A Tags: Cell Struct Funct Source Type: journals

Differential Ras activation between caveolae/raft and non-raft microdomains.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 develo...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Fukano T, Sawano A, Ohba Y, Matsuda M, Miyawaki A Tags: Cell Struct Funct Source Type: journals

Induction of beating by imposed bending or mechanical pulse in demembranated, motionless sea urchin sperm flagella at very low ATP concentrations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Ishikawa R, Shingyoji C Tags: Cell Struct Funct Source Type: journals

Heavy ion microbeam irradiation induces ultrastructural changes in isolated single fibers of skeletal muscle.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 a...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Hino M, Wada S, Tajika Y, Morimura Y, Hamada N, Funayama T, Sakashita T, Kakizaki T, Kobayashi Y, Yorifuji H Tags: Cell Struct Funct Source Type: journals

ARMET is a soluble ER protein induced by the unfolded protein response via ERSE-II element.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 we...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Mizobuchi N, Hoseki J, Kubota H, Toyokuni S, Nozaki J, Naitoh M, Koizumi A, Nagata K Tags: Cell Struct Funct Source Type: journals

Quantitative analysis of cortical actin filaments during polar body formation in starfish oocytes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Hamaguchi Y, Numata T, K Satoh S Tags: Cell Struct Funct Source Type: journals

Functional domain analysis of human HP1 isoforms in Drosophila.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 fo...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Kato M, Kato Y, Nishida M, Hayakawa T, Haraguchi T, Hiraoka Y, H Inoue Y, Yamaguchi M Tags: Cell Struct Funct Source Type: journals

Role of IRS and PHIP on insulin-induced tyrosine phosphorylation and distribution of IRS proteins.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 mut...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Kaburagi Y, Okochi H, Satoh S, Yamashita R, Hamada K, Ikari K, Yamamoto-Honda R, Terauchi Y, Yasuda K, Noda M Tags: Cell Struct Funct Source Type: journals

Implication of amphiphysin 1 and dynamin 2 in tubulobulbar complex formation and spermatid release.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 prote...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Kusumi N, Watanabe M, Yamada H, Li SA, Kashiwakura Y, Matsukawa T, Nagai A, Nasu Y, Kumon H, Takei K Tags: Cell Struct Funct Source Type: journals

A novel function of plant histone H1: microtubule nucleation and continuous plus end association.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 cell...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Hotta T, Haraguchi T, Mizuno K Tags: Cell Struct Funct Source Type: journals

A Drosophila orthologue of larp protein family is required for multiple processes in male meiosis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 fir...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Ichihara K, Shimizu H, Taguchi O, Yamaguchi M, Inoue YH Tags: Cell Struct Funct Source Type: journals

Psg18 is specifically expressed in follicle-associated epithelium.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 Ps...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Kawano K, Ebisawa M, Hase K, Fukuda S, Hijikata A, Kawano S, Date Y, Tsuneda S, Itoh K, Ohno H Tags: Cell Struct Funct Source Type: journals

Endothelial cells constituting blood-nerve barrier have highly specialized characteristics as barrier-forming cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Sano Y, Shimizu F, Nakayama H, Abe M, Maeda T, Ohtsuki S, Terasaki T, Obinata M, Ueda M, Takahashi R, Kanda T Tags: Cell Struct Funct Source Type: journals

Identification of novel nuclear localization signals of Drosophila myeloid leukemia factor.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 o...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Sugano W, Yamaguchi M Tags: Cell Struct Funct Source Type: journals

Involvement of p120 carboxy-terminal domain in cadherin trafficking.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 expressio...
Source: Cell Structure and Function - January 1, 2007 Category: Cytology Authors: Liu H, Komiya S, Shimizu M, Fukunaga Y, Nagafuchi A Tags: Cell Struct Funct Source Type: journals