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Structure, function and contribution of polysaccharide intercellular adhesin (PIA) to Staphylococcus epidermidis biofilm formation and pathogenesis of biomaterial-associated infections.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Staphylococcus epidermidis is of major importance in infections associated with indwelling medical devices. The tight pathogenic association is essentially linked to the species ability to form adherent biofilms on artificial surfaces. Aiming at identifying novel targets for vaccination or therapy much effort has been made to unravel the molecular mechanisms leading to S. epidermidis biofilm formation. At present, polysaccharide intercellular adhesin (PIA) is the best studied factor involved in S. epidermidis biofilm accumulation. PIA is a glycan of beta-1,6-linked 2-acetamido-2-deoxy-D-glucopyranosyl residues of which...
Source: European Journal of Cell Biology - November 12, 2009 Category: Cytology Authors: Rohde H, Frankenberger S, Zähringer U, Mack D Tags: Eur J Cell Biol Source Type: journals

Molecular interaction of Siglecs (sialic acid-binding Ig-like lectins) with sialylated ligands on Trypanosoma cruzi.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The protozoan parasite Trypanosoma cruzi (T. cruzi) is transmitted by blood-sucking insect vectors. After transmission, parasites circulate in the blood as trypomastigotes and invade a variety of cells to multiply intracellularly as amastigotes. The acute phase triggers an immune response that restricts the dissemination and proliferation of parasites. However, parasites are able to persist in different tissues for decades causing the pathology of Chagas' disease. T. cruzi expresses a trans-sialidase (TS). This unique enzyme transfers sialic acid from host glycoconjugates to mucin-like molecules on the parasite and is ...
Source: European Journal of Cell Biology - November 10, 2009 Category: Cytology Authors: Jacobs T, Erdmann H, Fleischer B Tags: Eur J Cell Biol Source Type: journals

Glycosyltransferases involved in the biosynthesis of the inner core region of different lipopolysaccharides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The inner core of lipopolysaccharide (LPS) structures in Gram-negative bacteria is considered a highly conserved region. The sugar connecting the membrane-associated lipid A moiety with the hydrophilic saccharide moiety, 3-deoxy-alpha-d-manno-oct-2-ulosonic acid (Kdo) is present in every LPS molecule investigated but it may be partially replaced by d-glycero-alpha-d-talo-oct-2-ulosonic acid (Ko). l-Glycero-alpha-d-manno-heptose (Hep) and phosphate residues are part of most but not all LPS structures and additionally, modifications with 4-amino-4-deoxy-beta-l-arabinose (Ara4N) residues occur in some. A number of differe...
Source: European Journal of Cell Biology - November 7, 2009 Category: Cytology Authors: Gronow S, Brade H Tags: Eur J Cell Biol Source Type: journals

DC-SIGN and mannosylated surface structures of Mycobacterium tuberculosis: a deceptive liaison.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is recognized by pattern recognition receptors on macrophages and dendritic cells, thereby triggering phagocytosis, antigen presentation to T cells and cytokine secretion. The dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin (DC-SIGN) is a calcium-dependent carbohydrate-binding protein with specificity for mannose-containing glycoconjugates and fucose-containing Lewis antigens. Mannosylated moieties of the mycobacterial cell wall, such as mannose-capped lipoarabinomannan (manLAM) or higher-order phosphatidylinosito...
Source: European Journal of Cell Biology - November 3, 2009 Category: Cytology Authors: Ehlers S Tags: Eur J Cell Biol Source Type: journals

Differential localization to cytoplasm, nucleus or P-bodies of yeast PKA subunits under different growth conditions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Our aim in this work was to further characterize the complexity and specificity of the three different isoforms (Tpk1, Tpk2 and Tpk3) of the catalytic and regulatory (Bcy1) subunits of PKA in Saccharomyces cerevisiae. We thus analyzed the subcellular localization of the PKA subunits in living cells by using strains carrying GFP (green fluorescent protein) fused to each PKA subunit. During exponential growth on glucose, both Bcy1 and Tpk2 localized in the nucleus, whereas Tpk1 and Tpk3 showed a mixed pattern of nucleo-cytoplasmic localization. During exponential growth on glycerol and during stationary phase, the PKA su...
Source: European Journal of Cell Biology - October 2, 2009 Category: Cytology Authors: Tudisca V, Recouvreux V, Moreno S, Boy-Marcotte E, Jacquet M, Portela P Tags: Eur J Cell Biol Source Type: journals

Molecular mechanisms underlying the pro-inflammatory synergistic effect of tumor necrosis factor alpha and interferon gamma in human microvascular endothelium.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tumor necrosis factor alpha (TNFalpha) and interferon gamma (IFNgamma) are among the most potent cytokines involved in orchestrating the inflammation response. The molecular mechanisms implicated in the synergism between cytokines are still poorly characterized. We demonstrate that both cytokines dose-dependently stimulate IFNgamma-inducible-protein-of-10-kDa (IP-10) secretion in human microvascular endothelial cells (HMEC-1), showing a potent synergism which is not restricted to IP-10, but is also evident for monokine-induced-by-IFNgamma (MIG) and IL-6 secretion. Immunofluorescence analysis reveals that TNFalpha and I...
Source: European Journal of Cell Biology - September 24, 2009 Category: Cytology Authors: Lombardi A, Cantini G, Mello T, Francalanci M, Gelmini S, Cosmi L, Santarlasci V, Degl'innocenti S, Luciani P, Deledda C, Annunziato F, Forti G, Galli A, Serio M, Luconi M Tags: Eur J Cell Biol Source Type: journals

Blood monocytes stimulate migration of human pancreatic carcinoma cells in vitro: The role of tumour necrosis factor - alpha.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In some types of cancers, tumour-infiltrating monocytes/macrophages (TIM) may be responsible for the formation of an invasive microenvironment in a manner dependent on the secretion of soluble mediators such as tumour necrosis factor-alpha (TNF). Human pancreatic carcinoma (HPC-4) cells are able to induce TNF production by monocytes. Here, the effect of human peripheral blood monocytes, precursors of TIM, on the motility of co-cultured HPC-4 cells, was directly analysed in vitro. A phenotypic transition, i.e., the appearance of rear-front polarised HPC-4 cells paralleled by their increased motility, and increased motil...
Source: European Journal of Cell Biology - September 23, 2009 Category: Cytology Authors: Baran B, Bechyne I, Siedlar M, Szpak K, Mytar B, Sroka J, La̢czna E, Madeja Z, Zembala M, Czyż J Tags: Eur J Cell Biol Source Type: journals

Soft micropillar interfaces of distinct biomechanics govern behaviour of periodontal cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A soft micropillar extracellular environment of distinct biomechanics is established by fabricating polydimethylsiloxane (PDMS) interfaces with pillar distances of 5, 7, 9 and 11mum and elasticity moduli of 0.6, 1.0 and 3.5 Mega Pascal. To allow for cell adhesion, the biomimetic concept of pillar head fibronectin (FN) biofunctionalisation is applied. This environmental set-up aims at the analysis of favourable conditions for cell behaviour of three periodontal cell-types, here reflected by the establishment of regular cell morphology and optimal collagen gene expression. Biomechanics of these predefined functionalised ...
Source: European Journal of Cell Biology - September 22, 2009 Category: Cytology Authors: Mussig E, Schulz S, Spatz JP, Ziegler N, Tomakidi P, Steinberg T Tags: Eur J Cell Biol Source Type: journals

TGF-beta1 down-regulates connexin 43 expression and gap junction intercellular communication in rat hepatic stellate cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Intercellular communication is an important tool used by the cells to effectively regulate concerted responses. Hepatic stellate cells (HSCs) communicate to each other through functional gap junctions composed of connexin 43 (Cx43) proteins. We show that exogenous human TGF-beta1 (hTGF-beta1), a pro-fibrotic stimulus, decreases Cx43 mRNA and protein in a rat HSC cell line and primary HSCs. Furthermore, hTGF-beta1 increases the phosphorylation of Cx43 at serine 368. These effects lead to a decrease in the gap junction intercellular communication between the HSCs, as shown by gap-FRAP analysis. We also observe the bindin...
Source: European Journal of Cell Biology - September 22, 2009 Category: Cytology Authors: Lim MC, Maubach G, Zhuo L Tags: Eur J Cell Biol Source Type: journals

Tools for correlative cryo-fluorescence microscopy and cryo-electron tomography applied to whole mitochondria in human endothelial cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe a cryo-FM setup and workflow for correlative cryo-fluorescence and cryo-electron microscopy (cryo-CLEM) that can be easily implemented. Cells are grown on finder grids, vitally labeled with one or two fluorescent dyes, and vitrified. After a structure is located by cryo-FM (with 0.4mum resolution), its image coordinates are translated to cryo-ET stage coordinates via a home-built software routine. We tested our workflow on whole mount primary human umbilical vein endothelial cells. The correlative routine enabled us to investigate mitochondrial ultrastructure for the first time on intact human mitochondria, and...
Source: European Journal of Cell Biology - August 30, 2009 Category: Cytology Authors: van Driel LF, Valentijn JA, Valentijn KM, Koning RI, Koster AJ Tags: Eur J Cell Biol Source Type: journals

Golgi polarity does not correlate with speed or persistence of freely migrating fibroblasts.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The polarization of the Golgi has long been thought to be important for cell migration. Here we show that Rat2 cells at the edge of an artificial wound repolarize the Golgi relative to the nucleus to face the direction of migration into the wound. However, in the absence of cues from neighboring cells, individual cells do not display Golgi polarity relative to the direction in which they are moving. Instead, the positioning of the Golgi relative to the nucleus remains relatively constant over time and does not reflect changes in the direction of migration. Consistent with this observation, we observe only a slight bias...
Source: European Journal of Cell Biology - August 30, 2009 Category: Cytology Authors: Uetrecht AC, Bear JE Tags: Eur J Cell Biol Source Type: journals

Thymidine kinase 1 expression defines an activated G1 state of the cell cycle as revealed with site-specific antibodies and ArrayScan assays.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thymidine kinase 1 (TK1) is a DNA salvage enzyme involved in the synthesis of thymidine triphosphate needed during S phase. Although TK1 has been utilized as a cell proliferation marker for many years no well-characterized antibodies are available. The preparation and properties of two types of poly- and monoclonal anti-TK1 peptide antibodies are described and they are used to determine the levels of TK1 in intact cells. Expression of TK1, c-fos, cyclin B1, Ki67, phosphorylated histone H3, phosphorylated ribosomal protein S6, as well as bromodeoxyuridine (BrdU) incorporation in human normal dermal fibroblast cultures w...
Source: European Journal of Cell Biology - August 30, 2009 Category: Cytology Authors: Gasparri F, Wang N, Skog S, Galvani A, Eriksson S Tags: Eur J Cell Biol Source Type: journals

A role for the extracellular domain of Crumbs in morphogenesis of Drosophila photoreceptor cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Morphogenesis of Drosophila photoreceptor cells includes the subdivision of the apical membrane into the photosensitive rhabdomere and the associated stalk membrane, as well as a considerable elongation of the cell. Drosophila Crumbs (Crb), an evolutionarily conserved transmembrane protein, organizes an apical protein scaffold, which is required for elongation of the photoreceptor cell and extension of the stalk membrane. To further elucidate the role played by different Crb domains during eye morphogenesis, we performed a structure-function analysis in the eye. The analysis showed that the three variants tested, namel...
Source: European Journal of Cell Biology - August 27, 2009 Category: Cytology Authors: Richard M, Muschalik N, Grawe F, Ozüyaman S, Knust E Tags: Eur J Cell Biol Source Type: journals

Potentiation of paclitaxel-induced apoptosis by galectin-13 overexpression via activation of Ask-1-p38-MAP kinase and JNK/SAPK pathways and suppression of Akt and ERK1/2 activation in U-937 human macrophage cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Galectin-13 transcripts have been identified in several normal and malignant tissues, but the physiological function of galectin-13 is still poorly understood. Here, we present evidence for its possible role in promoting cell death in the U-937 human macrophage cell line. Transfection of U-937 human macrophages by a galectin-13 cDNA-containing mammalian expression vector increased the galectin-13 level and sensitized the cells to stress stimuli. Galectin-13 overexpression facilitated paclitaxel-induced cell death and nuclear translocation of apoptosis-inducing factor (AIF) and endonuclease-G without inducing mitochondr...
Source: European Journal of Cell Biology - August 27, 2009 Category: Cytology Authors: Boronkai A, Bellyei S, Szigeti A, Pozsgai E, Bognar Z, Sumegi B, Gallyas F Tags: Eur J Cell Biol Source Type: journals

Mutations in the Saccharomyces cerevisiae vacuolar fusion proteins Ccz1, Mon1 and Ypt7 cause defects in cell cycle progression in a num1Delta background.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we analyze these synthetic effects and we show that the mutants ccz1Deltanum1Delta, mon1Deltanum1Delta and ypt7Deltanum1Delta exhibit severe defects in cell cycle progression. A large fraction of the mutant cells enter a new cell division cycle without having completed mitotic exit, leading to the accumulation of multinuclear, anuclear and multibudded cells. The double deletion strains display also increased sensitivity to calcium ions. The cell-cycle defects are only weakly observed if deletions of other vacuolar protein sorting genes are combined with num1Delta or if other nuclear-migration genes are delete...
Source: European Journal of Cell Biology - August 20, 2009 Category: Cytology Authors: Hoffman-Sommer M, Kucharczyk R, Piekarska I, Kozlowska E, Rytka J Tags: Eur J Cell Biol Source Type: journals

A mutation within the transmembrane domain of melanosomal protein Silver (Pmel17) changes lumenal fragment interactions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Melanocytes synthesize and store melanin within tissue-specific organelles, the melanosomes. Melanin deposition takes place along fibrils found within these organelles and fibril formation is known to depend on trafficking of the membrane glycoprotein Silver/Pmel17. However, correctly targeted, full-length Silver/Pmel17 cannot form fibers. Proteolytic processing in endosomal compartments and the generation of a lumenal Malpha fragment that is incorporated into amyloid-like structures is also essential. Dominant White (DWhite), a mutant form of Silver/Pmel17 first described in chicken, causes disorganized fibers and sev...
Source: European Journal of Cell Biology - August 10, 2009 Category: Cytology Authors: Kuliawat R, Santambrogio L Tags: Eur J Cell Biol Source Type: journals

The germline stem cells of Drosophila melanogaster partition DNA non-randomly.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Immortal Strand Hypothesis proposes that asymmetrically dividing stem cells cosegregate chromatids to retain ancestral DNA templates. Using both pulse-chase and label retention assays, we show that non-random partitioning of DNA occurs in germline stem cells (GSCs) in the Drosophila ovary as these divide asymmetrically to generate a new GSC and a differentiating cystoblast. This process is disrupted when GSCs are forced to differentiate through the overexpression of Bag of Marbles, a factor that impels the terminal differentiation of cystoblasts. When Decapentaplegic, a ligand which maintains the undifferentiated s...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Karpowicz P, Pellikka M, Chea E, Godt D, Tepass U, van der Kooy D Tags: Eur J Cell Biol Source Type: journals

Glandular tissue from human pancreas and salivary gland yields similar stem cell populations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Stem cells derived from pancreatic tissue are well characterized and exhibit a broad plasticity as they can differentiate beyond lineage boundaries into many cell types. The aim of this study was the comparative characterization of pancreatic stem cells with one other derivate of the embryonic foregut, namely salivary glands, for the existence of similar stem cell populations. The expression of stem cell markers as well as lineage-specific markers was detected by reverse transcription polymerase chain reaction, flow cytometry and immuncytochemical staining. The isolated cells from salivary glands and pancreas grew adhe...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Gorjup E, Danner S, Rotter N, Habermann J, Brassat U, Brummendorf TH, Wien S, Meyerhans A, Wollenberg B, Kruse C, von Briesen H Tags: Eur J Cell Biol Source Type: journals

Negative regulation of fibroblast growth factor 10 (FGF-10) by polyoma enhancer activator 3 (PEA3).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
FGF-10 plays an important role in development and disease, acting as the key ligand for FGFR2B to regulate cell proliferation, migration and differentiation. Aberrant FGF signalling is implicated in tumourigenesis, with several cancer studies reporting FGF-10 or FGFR2B upregulation or identifying activating mutations in Fgfr2. We used 5' RACE to identify a novel transcription start site for murine Fgf-10. Conventional in silico analysis predicted multiple binding sites for the transcription factor PEA3 upstream of this site. Binding was confirmed by chromatin immunopreciptation, and functional significance was studied ...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Chioni AM, Grose R Tags: Eur J Cell Biol Source Type: journals

Serglycin proteoglycan is not implicated in localizing exocrine pancreas enzymes to zymogen granules.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Storage and release of proteins from granules forms the basis of cellular functions as diverse as cell mediated cytotoxicity, neuronal communication, activation of muscle fibres, and release of hormones or digestive enzymes from endocrine and exocrine glands, such as the pancreas. Serglycin is the major intracellular proteoglycan of haematopoietic cells. Serglycin is important for localization of proteins in granules of different haematopoietic cell types. Previous reports have indicated a role for serglycin in granule formation and localization of zymogens in granules of the exocrine pancreas in rat. We here present d...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Niemann CU, Cowland JB, Ralfkiaer E, Abrink M, Pejler G, Borregaard N Tags: Eur J Cell Biol Source Type: journals

Cathepsin X prevents an effective immune response against Helicobacter pylori infection.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we demonstrate its role in regulating the immune response to infection with H. pylori. The level of cathepsin X was determined in THP-1 monocyte cells primed with H. pylori antigens isolated from subjects suffering from gastritis, who had either eradicated or not the disease after the antibiotic therapy. We show that the specific clinical outcome of H. pylori eradication therapy correlates strongly with the membrane expression of cathepsin X in stimulated THP-1 cells, being significantly higher after stimulation with H. pylori strains from those subjects who did not respond to antibiotic therapy. The same ant...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Obermajer N, Magister S, Kopitar AN, Tepes B, Ihan A, Kos J Tags: Eur J Cell Biol Source Type: journals

Peptides modeled after the alpha-domain of metallothionein induce neurite outgrowth and promote survival of cerebellar granule neurons.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Metallothionein (MT) is a metal-binding protein capable of preventing oxidative stress and apoptotic cell death in the central nervous system of mammals, and hence is of putative therapeutic value in the treatment of neurodegenerative disorders. Recently, we demonstrated that a peptide modeled after the beta-domain of MT, EmtinB, induced neurite outgrowth and increased neuronal survival through binding to receptors of the low-density lipoprotein receptor family (LDLR). The present study identified two MT alpha-domain-derived peptide sequences termed EmtinAn and EmtinAc, each consisting of 14 amino acids, as potent stim...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Asmussen JW, Ambjørn M, Bock E, Berezin V Tags: Eur J Cell Biol Source Type: journals

Mutation in Rab11 results in abnormal organization of ommatidial cells and activation of JNK signaling in the Drosophila eye.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Rab11(mo), a P insertion line of Rab11 showed degenerated ommatidia and excess cell death in larval/pupal eyes. Here, we demonstrate that Rab11 is essential for normal organization of ommatidial cells and their survival in Drosophila, and a mutation in this gene results in cytoskeleton disruption and activation of JNK signaling in the eye. The spatial organization of various cell types in compound eye, viz., cone, photoreceptor, pigment and bristle cells, were disrupted in Rab11 mutants as revealed by immunostaining of F-actin and adherens and septate junction proteins. Genetic interaction studies indicated that mutati...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Tiwari AK, Roy JK Tags: Eur J Cell Biol Source Type: journals

Possible role for cellular FXIII in monocyte-derived dendritic cell motility.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The A subunit of plasma factor XIII (FXIII-A) is thought to function as an intracellular transglutaminase (TG) in the monocyte/macrophage lineage to regulate certain intracellular processes involving cytoskeleton remodeling, but its precise role and the functional consequences of its absence remain poorly understood. In the present study, we show that cellular FXIII (cFXIII) expression is largely upregulated during in vitro differentiation of monocytes into dendritic cells (DCs). Monodansyl-cadaverine, a competitive substrate of TG activity, inhibited basal and CCL19-stimulated migration of mature DCs. In agreement, FX...
Source: European Journal of Cell Biology - June 27, 2009 Category: Cytology Authors: Jayo A, Conde I, Lastres P, Jiménez-Yuste V, González-Manchón C Tags: Eur J Cell Biol Source Type: journals

Interaction of SH3P13 and DYDC1 protein: a germ cell component that regulates acrosome biogenesis during spermiogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The N-terminal BAR domain of endophilin has unique functions, such as affecting the curvature of the lipid membrane through its lysophosphatidic acid acyltransferase activity, binding of ATP and GTP and participating in tubulating activity. We recently demonstrated that SH3P13, a BAR domain-containing protein, assists in regulating clathrin-coated vesicle traffic that is crucial for acrosome biogenesis during spermatogenesis. DYDC1 was identified in a yeast two-hybrid screen from a human testis library by using the SH3P13 BAR domain as the bait. Consistent with the expression pattern of SH3P13, DYDC1 is exclusively exp...
Source: European Journal of Cell Biology - June 19, 2009 Category: Cytology Authors: Li S, Qiao Y, Di Q, Le X, Zhang L, Zhang X, Zhang C, Cheng J, Zong S, Koide SS, Miao S, Wang L Tags: Eur J Cell Biol Source Type: journals

Two isoforms of eukaryotic phospholipase C in Paramecium affecting transport and release of GPI-anchored proteins in vivo.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Surface proteins anchored by a glycosylphosphatidylinositol (GPI) residue in the cell membrane are widely distributed among eukaryotic cells. The GPI anchor is cleavable by a phospholipase C (PLC) leading to the release of such surface proteins, and this process is postulated to be essential in several systems. For higher eukaryotes, the responsible enzymes have not been characterized in any detail as yet. Here we characterize six PLCs in the ciliated protozoan, Paramecium, which, in terms of catalytic domains and architecture, all show characteristics of PLCs involved in signal transduction in higher eukaryotes. We sh...
Source: European Journal of Cell Biology - June 18, 2009 Category: Cytology Authors: Klöppel C, Müller A, Marker S, Simon M Tags: Eur J Cell Biol Source Type: journals

Image analysis of mast cell degranulation in a concentration gradient of stimuli formed in the channel between a glass plate and a silicon substrate.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Measurement of released granule components, popularly used to quantify mast cell exocytosis, does not deliver real-time information about degranulation at the single-cell level nor the ratio of responding/non-responding cells. Rather it provides, only end-point, bulk-population data. Here we studied degranulation of rat peritoneal mast cells dispersed in a narrow horizontal channel between a silicon substrate and a glass plate. Upon exposure to a concentration gradient of a soluble stimulus, degranulation started from those cells facing towards the highest concentration of stimulus. We captured images of exocytosing ce...
Source: European Journal of Cell Biology - June 7, 2009 Category: Cytology Authors: Nitta N, Aoki Y, Isogawa Y, Tsuchiya T, Kanegasaki S Tags: Eur J Cell Biol Source Type: journals

Constitutively active RhoA inhibits proliferation by retarding G(1) to S phase cell cycle progression and impairing cytokinesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The actions of RhoA in cytoskeletal regulation have been extensively studied. RhoA also contributes to proliferation and oncogenic transformation by less well-characterized means. Elevated RhoA signalling has been associated with human cancer; through increased RhoA expression, mutation or elevated expression of activating Rho guanine-nucleotide exchange factors (GEFs), or from deletion or decreased expression of inhibitory Rho GTPase-activating proteins (GAPs). Unlike the Ras oncogene, constitutively-activated GTPase-deficient RhoA mutants have not been identified in tumours. To investigate the effects of active RhoA ...
Source: European Journal of Cell Biology - June 7, 2009 Category: Cytology Authors: Morin P, Flors C, Olson MF Tags: Eur J Cell Biol Source Type: journals

Cgr11 encodes a secretory protein involved in cell adhesion.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We performed comparative proteomic analyses of pituitary tumor-derived cell lines, and found a new protein, preliminarily called hydrophobestin, which was produced only in somatotrophic cells, MtT/S, but not in non-hormone-producing cells, MtT/E. Hydrophobestin is encoded by the cell growth regulatory gene, Cgr11, which is known to have growth-suppressive potential in several cell lines. We have now sought to investigate the underlying events responsible for cell growth inhibition by hydrophobestin. Immunocytochemisty revealed that hydrophobestin is localized in the Golgi apparatus of MtT/S cells and Cgr11-transfected ...
Source: European Journal of Cell Biology - May 25, 2009 Category: Cytology Authors: Devnath S, Kataoka T, Miura K, Kusuda M, Kitamura K, Kumada Y, Mochiduki A, Kaneko K, Adachi A, Inoue K Tags: Eur J Cell Biol Source Type: journals

C-terminal tagging with eGFP yields new insights into expression of connexin45 but prevents rescue of embryonic lethal connexin45-deficient mice.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Connexin45 (Cx45) is a member of the connexin family which can form gap junction channels and is known to be expressed in several cell types in the embryonic as well as adult mouse including working cardiomyocytes and certain types of neurons. Until now its subcellular localization could not be unequivocally determined in certain tissues due to the lack of sensitive and specific antibodies. In order to investigate the localization of Cx45, we have generated a transgenic mouse expressing a fusion protein composed of Cx45 and eGFP under control of the endogenous Cx45 promoter using a bacterial artificial chromosome (BAC)...
Source: European Journal of Cell Biology - May 24, 2009 Category: Cytology Authors: von Maltzahn J, Kreuzberg MM, Matern G, Euwens C, Höher T, Wörsdörfer P, Willecke K Tags: Eur J Cell Biol Source Type: journals

Endogenous bone morphogenetic proteins in human bone marrow-derived multipotent mesenchymal stromal cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Primary human multipotent mesenchymal stromal cells (MSCs) are capable of self renewal or differentiation into several different lineages, including osteoblasts, chondrocytes and adipocytes. However, upon prolonged in vitro culture, MSCs tend to undergo spontaneous osteogenic differentiation. Here, we address the possible role of endogenous osteogenic bone morphogenetic proteins (BMPs) in in situ osteoblastic differentiation of human MSCs. Human MSCs consistently express biologically active BMP-2, BMP-4 and BMP-6 in addition to all BMP-activated receptors, which are functional as shown by the induction of alkaline phos...
Source: European Journal of Cell Biology - April 5, 2009 Category: Cytology Authors: Seib FP, Franke M, Jing D, Werner C, Bornhäuser M Tags: Eur J Cell Biol Source Type: journals

Anti-tropomyosin antibodies co-localise with actin microfilaments and label plasmodesmata.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The actin cytoskeleton and associated actin-binding proteins form a complex network involved in a number of fundamental cellular processes including intracellular trafficking. In plants, both actin and myosin have been localised to plasmodesmata, and thus it is likely that other actin-binding proteins are also associated with plasmodesmata structure or function. A 75-kDa protein, enriched in plasmodesmata-rich cell wall extracts from the green alga Chara corallina, was sequenced and found to contain three peptides with similarity to the animal actin-binding protein tropomyosin. Western blot analysis with anti-tropomyos...
Source: European Journal of Cell Biology - March 26, 2009 Category: Cytology Authors: Faulkner CR, Blackman LM, Collings DA, Cordwell SJ, Overall RL Tags: Eur J Cell Biol Source Type: journals

Rab11-FIP3 is a Rab11-binding protein that regulates breast cancer cell motility by modulating the actin cytoskeleton.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell adhesion and motility are very dynamic processes that require the temporal and spatial coordination of many cellular structures. ADP-ribosylation factor 6 (Arf6) has emerged as master regulator of endocytic membrane traffic and cytoskeletal dynamics during cell movement. Recently, a novel Arf6-binding protein known as FIP3/arfophilin/eferin has been identified. In addition to Arf6, FIP3 also interacts with Rab11, a small monomeric GTPase that regulates endocytic membrane transport. Both Arf6 and Rab11 GTPases have been implicated in regulation of cell motility. Here we test the role of FIP3 in breast carcinoma cel...
Source: European Journal of Cell Biology - March 25, 2009 Category: Cytology Authors: Jing J, Tarbutton E, Wilson G, Prekeris R Tags: Eur J Cell Biol Source Type: journals

Targeting the actin-binding protein VASP to late endosomes induces the formation of giant actin aggregates.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In vitro, the vasodilator-stimulated phosphoprotein (VASP) acts as a regulator of actin filament assembly in many ways. In cells it localizes to sites where actin is rapidly polymerized such as filopodia, lamellipodia, and focal adhesions. We have mistargeted VASP to the surface of the late endosome in Dictyostelium cells thereby inducing the formation of a dense actin aggregate which sequesters various actin-binding proteins and endosomal components. Depletion of these proteins from the cytoplasm leads to phenotypes mimicking the corresponding knockout cells. Some properties of the actin aggregate are reminiscent of H...
Source: European Journal of Cell Biology - March 24, 2009 Category: Cytology Authors: Schmauch C, Claussner S, Zöltzer H, Maniak M Tags: Eur J Cell Biol Source Type: journals

Intranasal delivery of cells to the brain.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The safety and efficacy of cell-based therapies for neurodegenerative diseases depends on the mode of cell administration. We hypothesized that intranasally administered cells could bypass the blood-brain barrier by migrating from the nasal mucosa through the cribriform plate along the olfactory neural pathway into the brain and cerebrospinal fluid (CSF). This would minimize or eliminate the distribution of cellular grafts to peripheral organs and will help to dispense with neurosurgical cell implantation. Here we demonstrate transnasal delivery of cells to the brain following intranasal application of fluorescently la...
Source: European Journal of Cell Biology - March 24, 2009 Category: Cytology Authors: Danielyan L, Schäfer R, von Ameln-Mayerhofer A, Buadze M, Geisler J, Klopfer T, Burkhardt U, Proksch B, Verleysdonk S, Ayturan M, Buniatian GH, Gleiter CH, Frey WH Tags: Eur J Cell Biol Source Type: journals

Protein 4.1 and its interaction with other cytoskeletal proteins in Xenopus laevis oogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In human red blood cells, protein 4.1 (4.1R) is an 80-kDa polypeptide that stabilizes the spectrin-actin network and anchors it to the plasma membrane. In non-erythroid cells there is a great variety of 4.1R isoforms, mainly generated by alternative pre-mRNA splicing, which localize at various intracellular sites, including the nucleus. We studied protein 4.1R distribution in relation to beta-spectrin, actin and cytokeratin during Xenopus oogenesis. Immunoprecipitation experiments indicate that at least two isoforms of protein 4.1R are present in Xenopus laevis oocytes: a 56-kDa form in the cytoplasm and a 37-kDa form ...
Source: European Journal of Cell Biology - March 20, 2009 Category: Cytology Authors: Carotenuto R, Petrucci TC, Correas I, Vaccaro MC, De Marco N, Dale B, Wilding M Tags: Eur J Cell Biol Source Type: journals

Nerve fibroblast impact on Schwann cell behavior.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In order to reveal non-neuronal cell interactions after peripheral nerve lesions, we began to analyze the impact of sciatic nerve fibroblasts on Schwann cells in vitro. Both cell types are considered to have opposite effects on axonal regeneration. Few data are available on how repulsive nerve fibroblasts affect neuritotrophic Schwann cells and thus might indirectly influence axonal regrowth. Using different culture systems in conjunction with time-lapse video recording, metabolic labeling, pharmacological intervention, RNAi knockdown, Western blotting and RT-PCR analysis, we found that nerve fibroblasts differentially...
Source: European Journal of Cell Biology - February 24, 2009 Category: Cytology Authors: Dreesmann L, Mittnacht U, Lietz M, Schlosshauer B Tags: Eur J Cell Biol Source Type: journals

Toxoplasma PRP1 is an ortholog of parafusin (PFUS) in vesicle scaffold assembly in Ca(2+)-regulated exocytosis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study tests the hypothesis that PRP1 is a functional ortholog of PFUS, functioning identically in Ca(2+)-regulated exocytosis. Electroporation of fluorescently labeled recombinant His-PRP1 into live Paramecium cells resulted in its localization to docked, dense-core secretory vesicles (DCSVs) in a pattern identical to endogenous PFUS. In tam8 mutants, defective in transport of DCSVs, the fluorescently labeled protein was restricted to the un-transported DCSVs. Specificity of PRP1 localization was demonstrated by electroporating labeled actin or pyruvate kinase, which both failed to localize to either docked or undocke...
Source: European Journal of Cell Biology - January 22, 2009 Category: Cytology Authors: Liu L, Tucker SC, Satir BH Tags: Eur J Cell Biol Source Type: journals

Expression of a functional epidermal growth factor receptor on human adipose-derived mesenchymal stem cells and its signaling mechanism.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Adult stem cells act as a pluripotent source of regenerative cells during tissue injury. Despite expanded research in stem cell biology, understanding how growth and migration of adipose-derived adult mesenchymal stem cells (ASC) are governed by interactions with growth factors is very limited. One important property of ASC is the presence of the epidermal growth factor (EGF) receptor and the cellular response to soluble EGF. Expression of the EGF receptor was proven by PCR and Western blotting. Signal transduction was analyzed by Western blotting and PhosFlow assay. EGF caused robust phosphorylation of SHC and ERK1/2,...
Source: European Journal of Cell Biology - January 22, 2009 Category: Cytology Authors: Baer PC, Schubert R, Bereiter-Hahn J, Plößer M, Geiger H Tags: Eur J Cell Biol Source Type: journals

Neurofilament subunit (NFL) head domain phosphorylation regulates axonal transport of neurofilaments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Neurofilaments are the intermediate filaments of neurons and are synthesised in neuronal cell bodies and then transported through axons. Neurofilament light chain (NFL) is a principal component of neurofilaments, and phosphorylation of NFL head domain is believed to regulate the assembly of neurofilaments. However, the role that NFL phosphorylation has on transport of neurofilaments is poorly understood. To address this issue, we monitored axonal transport of phosphorylation mutants of NFL. We mutated four known phosphorylation sites in NFL head domain to either preclude phosphorylation, or mimic permanent phosphorylat...
Source: European Journal of Cell Biology - January 13, 2009 Category: Cytology Authors: Yates DM, Manser C, De Vos KJ, Shaw CE, McLoughlin DM, Miller CC Tags: Eur J Cell Biol Source Type: journals

ER-associated complexes (ERACs) containing aggregated cystic fibrosis transmembrane conductance regulator (CFTR) are degraded by autophagy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The ubiquitin-proteasome pathway and autophagy are the two major mechanisms responsible for the clearance of cellular proteins. We have used the yeast Saccharomyces cerevisiae as a model system and the cystic fibrosis transmembrane conductance regulator (CFTR) as a model substrate to study the interactive function of these two pathways in the degradation of misfolded proteins. EGFP-tagged human CFTR was introduced into yeast and expressed under a copper-inducible promoter. The localization and degradation of EGFP-CFTR in live cells were monitored by time-lapse imaging following its de novo synthesis. EGFP-CFTR first ap...
Source: European Journal of Cell Biology - January 6, 2009 Category: Cytology Authors: Fu L, Sztul E Tags: Eur J Cell Biol Source Type: journals

CGRP-alpha responsiveness of adult rat ventricular cardiomyocytes from normotensive and spontaneously hypertensive rats.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, it is shown that CGRP-alpha exerts dual effects on cardiomyocytes favouring the negative contractile effect at very low concentrations. This effect is compensated in chronic pressure-overloaded hearts and converted into a positive inotropism. PMID: 19128857 [PubMed - as supplied by publisher] (Source: European Journal of Cell Biology)
Source: European Journal of Cell Biology - January 5, 2009 Category: Cytology Authors: Schlier A, Schreckenberg R, Abdallah Y, Krasteva G, Piper HM, Pfeil U, Kummer W, Schlüter KD Tags: Eur J Cell Biol Source Type: journals

Culture and functional studies of mouse macrophages on native-like fibrillar type I collagen.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Freshly isolated, starch-elicited mouse peritoneal macrophages (Mø) attached very efficiently to type I collagen in vitro, if collagen molecules were arranged in ordered supra-molecular assemblies corresponding to the precursor native fibrils. After 6-20h of incubation, the collagen-bound cells were observed to secrete fibronectin, which presumably enhanced cell-collagen interaction associated with cellular differentiation. Mø attachment to collagen could be temporarily inhibited by addition of the linear tri-peptide Arg-Gly-Asp (RGD) to the culture media. This inhibition was much more pronounced when using t...
Source: European Journal of Cell Biology - January 3, 2009 Category: Cytology Authors: Philippeaux MM, Bargetzi JP, Pache JC, Robert J, Spiliopoulos A, Mauël J Tags: Eur J Cell Biol Source Type: journals

Akt regulates vitamin D3-induced leukemia cell functional differentiation via Raf/MEK/ERK MAPK signaling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
1,25-Dihydroxyvitamin D3 (vitamin D3) induces differentiation of HL-60 human myeloid leukemia cells; however, the signaling mechanism governing these effects is not fully clear. Here, we show that vitamin D3 induced functional differentiation by Akt through Raf/MEK/ERK MAPK signaling. Vitamin D3 downregulated Akt, weakened Akt-Raf1 interaction, and subsequently activated the Raf/MEK/ERK MAPK pathway. Pharmacological inhibition of MEK/ERK crippled differentiation in response to vitamin D3. Ectopic overexpression of Akt inhibited MAPK signaling, downregulated cyclin-dependent kinase (CDK) inhibitors p21(Wip1/Cip1) and p2...
Source: European Journal of Cell Biology - December 4, 2008 Category: Cytology Authors: Wang J, Zhao Y, Kauss MA, Spindel S, Lian H Tags: Eur J Cell Biol Source Type: journals

Microfilament dynamics during HaCaT cell volume regulation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell volume is an important parameter in many physiological processes, and is closely regulated in many cell types. In those cells, swelling induced by hypotonic media is followed by an ion-driven regulatory volume decrease. In many cell types, this regulatory volume decrease requires an intact actin cytoskeleton. Therefore, we investigated the changes in the structure and polymerization state of the actin cytoskeleton in HaCaT keratinocytes during cell swelling and regulatory volume decrease. Disruption of the actin cytoskeleton by 2muM cytochalasin D inhibits regulatory volume decrease in HaCaT cells. Cells swollen i...
Source: European Journal of Cell Biology - November 24, 2008 Category: Cytology Authors: Blase C, Becker D, Kappel S, Bereiter-Hahn J Tags: Eur J Cell Biol Source Type: journals

Functional interaction of the cation channel transient receptor potential vanilloid 4 (TRPV4) and actin in volume regulation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Many vertebrate cells react to hypotonic conditions with swelling, followed by an active downregulation of the cell volume; a progress called regulatory volume decrease (RVD). While the actual process of volume decrease by loss of osmotically active molecules like K(+) and Cl(-), followed by water efflux has been extensively investigated, the signal for activation of RVD still remains obscure. Studies with different cell lines demonstrated a participation of the cation channel transient receptor potential vanilloid 4 (TRPV4) as well as the actin cytoskeleton in volume regulation. Therefore, we analyzed putative links b...
Source: European Journal of Cell Biology - November 21, 2008 Category: Cytology Authors: Becker D, Bereiter-Hahn J, Jendrach M Tags: Eur J Cell Biol Source Type: journals

The LINC-less granulocyte nucleus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The major blood granulocyte (neutrophil) is rapidly recruited to sites of bacterial and fungal infections. It is a highly malleable cell, allowing it to squeeze out of blood vessels and migrate through tight tissue spaces. The human granulocyte nucleus is lobulated and exhibits a paucity of nuclear lamins, increasing its capability for deformation. The present study examined the existence of protein connections between the nuclear envelope and cytoskeletal elements (the LINC complex) in differentiated cell states (i.e. granulocytic, monocytic and macrophage) of the human leukemic cell line HL-60, as well as in human bl...
Source: European Journal of Cell Biology - November 17, 2008 Category: Cytology Authors: Olins AL, Hoang TV, Zwerger M, Herrmann H, Zentgraf H, Noegel AA, Karakesisoglou I, Hodzic D, Olins DE Tags: Eur J Cell Biol Source Type: journals

IGF-I, EGF, and sex steroids regulate autophagy in bovine mammary epithelial cells via the mTOR pathway.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, autophagy in bovine MEC undergoes complex regulation, where its activity is controlled by survival pathways dependent on IGF-I and EGF, which are involved in suppression of autophagy, and by pregnancy steroids, which act as inducers of the process. PMID: 19013662 [PubMed - as supplied by publisher] (Source: European Journal of Cell Biology)
Source: European Journal of Cell Biology - November 13, 2008 Category: Cytology Authors: Sobolewska A, Gajewska M, Zarzyńska J, Gajkowska B, Motyl T Tags: Eur J Cell Biol Source Type: journals

The membrane-tubulating potential of amphiphysin 2/BIN1 is dependent on the microtubule-binding cytoplasmic linker protein 170 (CLIP-170).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, our goal was to characterize the functional role of a ubiquitously expressed amphiphysin 2/BIN1 by the characterization of new molecular partners. We performed a two-hybrid screen with an isoform of amphiphysin 2/BIN1 expressed in HeLa cells. We identified CLIP-170 as an amphiphysin 2/BIN1-interacting molecule. CLIP-170 is a plus-end tracking protein involved in microtubule (MT) stability and recruitment of dynactin. The binding between amphiphysin 2/BIN1 and CLIP-170 is dependent on the N-terminal part of amphiphysin 2 (mostly the BAR domain) and an internal coiled-coil region of CLIP-170. This partnership ...
Source: European Journal of Cell Biology - November 10, 2008 Category: Cytology Authors: Meunier B, Quaranta M, Daviet L, Hatzoglou A, Leprince C Tags: Eur J Cell Biol Source Type: journals

Knockdown of the co-chaperone Hop promotes extranuclear accumulation of Stat3 in mouse embryonic stem cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A key event in the mechanism of mouse embryonic stem cell (mESC) pluripotency is phosphorylation, dimerisation and translocation to the nucleus of the signal transducer and activator of transcription3, Stat3. We used RNAi to suppress the levels of the co-chaperone Hsp70/Hsp90 organising protein (Hop) in an mESC line. Hop knockdown caused 68% depletion in Stat3 mRNA levels, decreased soluble pYStat3 levels, and led to an extranuclear accumulation of Stat3. The major binding partner of Hop, Hsp90, co-localised with a small non-nuclear fraction of Stat3 in mESCs, and both Stat3 and Hop co-precipitated with Hsp90. Hop knoc...
Source: European Journal of Cell Biology - November 7, 2008 Category: Cytology Authors: Longshaw VM, Baxter M, Prewitz M, Blatch GL Tags: Eur J Cell Biol Source Type: journals