Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Terminal steps in the transport of the vesicular stomatitis virus glycoprotein (G protein) in the Golgi stack have been reconstituted in a cell-free system. Incorporation of sialic acid into the oligosaccharide chains of G protein was used to monitor transport into the trans Golgi compartment. Transport-coupled sialylation required cytosol, ATP, an N-ethylmaleimide-sensitive factor extractable from Golgi membranes, and long chain acyl coenzyme A. The G protein receiving sialic acid in the cell-free system begins its in vitro transport bearing galactose residues acquired in vivo. Earlier reports (Balch, W. E., Dunphy, W. G., Braell, W. A., and Rothman, J. E. (1984a) Cell 39, 405-416) documented that transport of G protein into the medial (GlcNAc Transferase-containing) compartment is reconstituted under the same conditions. On the basis of the results reported here, it now appears that a more complete set of transport operations of the Golgi stack may be simultaneously reconstituted.
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PMID:Transport of the vesicular stomatitis glycoprotein to trans Golgi membranes in a cell-free system. 304 Jul 52

Using the glycoprotein of the tsO45 mutant of vesicular stomatitis virus (VSV-G) as a marker, we have developed a system capable of measuring vesicular transport from the endoplasmic reticulum (ER) to the trans Golgi network (TGN) in vitro. Movement from the ER to the cis Golgi compartment was assessed by the conversion of VSV-G from a totally endoglycosidase D (endo D)-resistant form to a species containing one endo D-resistant and one endo D-sensitive oligosaccharide (GD1). Similarly, delivery to the medial cisternae was measured by the appearance of the completely endo D-sensitive form of VSV-G (GD2) or by the acquisition of complete resistance to endoglycosidase H (endo H) (GHr) and delivery to the TGN by the appearance of an endo H-resistant form of VSV-G which was sensitive to digestion with neuraminidase and subsequently beta-galactosidase (GHt). Movement between each sequential compartment required ATP and soluble proteins (cytosol) and was inhibited by nonhydrolyzable analogues of GTP and by an antibody toward the N-ethylmaleimide-sensitive factor NSF. In contrast, fractionation of the cytosol by ammonium sulfate precipitation indicated that distinct proteins were required for movement between successive compartments. Similarly, inclusion of a mutant form of the small molecular weight GTP-binding protein rab1A inhibited movement between the ER and cis Golgi, and between the cis and medial cisternae, but did not affect transport from the medial Golgi to the TGN. Conversely, the protein kinase inhibitor staurosporine prevented movement between the medial Golgi and the TGN but did not influence transport between the ER and early Golgi compartments. This study provides the first demonstration that vesicular transport between the ER and TGN can be reconstituted in a cytosol-dependent fashion in vitro, allowing a direct analysis of the roles of individual components in multiple transport events.
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PMID:Differential inhibition of multiple vesicular transport steps between the endoplasmic reticulum and trans Golgi network. 838 97

We have developed a system that recreates in vitro the generation of post-Golgi vesicles from an isolated Golgi fraction prepared from vesicular stomatitis virus- or influenza virus-infected Madin-Darby canine kidney or HepG2 cells. In this system, vesicle generation is temperature- and ATP-dependent and requires a supply of cytosolic proteins, including an N-ethylmaleimide-sensitive factor distinct from NSF. Cytosolic proteins obtained from yeast were as effective as mammalian cytosolic proteins in supporting vesicle formation and had the same requirements. The vesicles produced (50-80 nm in diameter) are depleted of the trans Golgi marker sialyltransferase, contain the viral glycoprotein molecules with their cytoplasmic tails exposed, and do not show an easily recognizable protein coat. Vesicle generation was inhibited by brefeldin A, which indicates that it requires the activation of an Arf-like GTP-binding protein that promotes assembly of a vesicle coat. Vesicles formed in the presence of the nonhydrolyzable GTP analogue guanosine 5'-3-O-(thio)triphosphate retained a nonclathrin protein coat resembling that of COP-coated vesicles, and sedimented more rapidly in a sucrose gradient than the uncoated ones generated in its absence. This indicates that GTP hydrolysis is not required for vesicle generation but that it is for vesicle uncoating. The activity of a Golgi-associated protein kinase C (PKC) was found to be necessary for the release of post-Golgi vesicles, as indicated by the capacity of a variety of inhibitors and antibodies to PKC to suppress it, as well as by the stimulatory effect of the PKC activator 12-O-tetradecanoylphorbol-13-acetate.
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PMID:The in vitro generation of post-Golgi vesicles carrying viral envelope glycoproteins requires an ARF-like GTP-binding protein and a protein kinase C associated with the Golgi apparatus. 866 71

Yeast Bet1p participates in vesicular transport from the endoplasmic reticulum to the Golgi apparatus and functions as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) associated with ER-derived vesicles. A mammalian protein (rbet1) homologous to Bet1p was recently identified, and it was concluded that rbet1 is associated with the Golgi apparatus based on the subcellular localization of transiently expressed epitope-tagged rbet1. In the present study using rabbit antibodies raised against the cytoplasmic domain of rbet1, we found that the majority of rbet1 is not associated with the Golgi apparatus as marked by the Golgi mannosidase II in normal rat kidney cells. Rather, rbet1 is predominantly associated with vesicular spotty structures that concentrate in the peri-Golgi region but are also present throughout the cytoplasm. These structures colocalize with the KDEL receptor and ERGIC-53, which are known to be enriched in the intermediate compartment. When the Golgi apparatus is fragmented by nocodazole treatment, a significant portion of rbet1 is not colocalized with structures marked by Golgi mannosidase II or the KDEL receptor. Association of rbet1 in cytoplasmic spotty structures is apparently not altered by preincubation of cells at 15 degrees C. However, upon warming up from 15 to 37 degrees C, rbet1 concentrates into the peri-Golgi region. Furthermore, rbet1 colocalizes with vesicular stomatitis virus G-protein en route from the ER to the Golgi. Antibodies against rbet1 inhibit in vitro transport of G-protein from the ER to the Golgi apparatus in a dose-dependent manner. This inhibition can be neutralized by preincubation of antibodies with recombinant rbet1. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle docking but before the actual fusion event. Antibodies against rbet1 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. These results suggest that rbet1 may be involved in the docking process of ER-derived vesicles with the cis-Golgi membrane.
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PMID:The mammalian protein (rbet1) homologous to yeast Bet1p is primarily associated with the pre-Golgi intermediate compartment and is involved in vesicular transport from the endoplasmic reticulum to the Golgi apparatus. 938 63

Expressed sequence tags coding for a potential SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) were revealed during data base searches. The deduced amino acid sequence of the complete coding region predicts a 217-residue protein with a COOH-terminal hydrophobic membrane anchor. Affinity-purified antibodies raised against the cytoplasmic region of this protein specifically detect a 29-kilodalton integral membrane protein enriched in the Golgi membrane. Indirect immunofluorescence microscopy reveals that this protein is mainly associated with the Golgi apparatus. When detergent extracts of the Golgi membrane are incubated with immobilized glutathione S-transferase alpha soluble N-ethylmaleimide-sensitive factor attachment protein (GST-alpha-SNAP), this protein was specifically retained. This protein has been independently identified and termed Vti1-rp2, and it is homologous to Vti1p, a yeast Golgi SNARE. We further show that Vti1-rp2 can be qualitatively coimmunoprecipitated with Golgi syntaxin 5 and syntaxin 6, suggesting that Vti1-rp2 exists in at least two distinct Golgi SNARE complexes. In cells microinjected with antibodies against Vti1-rp2, transport of the envelope protein (G-protein) of vesicular stomatitis virus from the endoplasmic reticulum to the plasma membrane was specifically arrested at the Golgi apparatus, providing further evidence for functional importance of Vti1-rp2 in protein trafficking in the secretory pathway.
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PMID:A 29-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (Vti1-rp2) implicated in protein trafficking in the secretory pathway. 970 16

Yeast Sec22p participates in both anterograde and retrograde vesicular transport between the endoplasmic reticulum (ER) and the Golgi apparatus by functioning as a v-SNARE (soluble N-ethylmaleimide-sensitive factor [NSF] attachment protein receptor) of transport vesicles. Three mammalian proteins homologous to Sec22p have been identified and are referred to as Sec22a, Sec22b/ERS-24, and Sec22c, respectively. The existence of three homologous proteins in mammalian cells calls for detailed cell biological and functional examinations of each individual protein. The epitope-tagged forms of all three proteins have been shown to be primarily associated with the ER, although functional examination has not been carefully performed for any one of them. In this study, using antibodies specific for Sec22b/ERS-24, it is revealed that endogenous Sec22b/ERS-24 is associated with vesicular structures in both the perinuclear Golgi and peripheral regions. Colabeling experiments for Sec22b/ERS-24 with Golgi mannosidase II, the KDEL receptor, and the envelope glycoprotein G (VSVG) of vesicular stomatitis virus (VSV) en route from the ER to the Golgi under normal, brefeldin A, or nocodazole-treated cells suggest that Sec22b/ERS-24 is enriched in the pre-Golgi intermediate compartment (IC). In a well-established semi-intact cell system that reconstitutes transport from the ER to the Golgi, transport of VSVG is inhibited by antibodies against Sec22b/ERS-24. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle/transport intermediate docking but before the actual fusion event. Antibodies against Sec22b/ERS-24 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. Transport of VSVG accumulated in pre-Golgi IC by incubation at 15 degreesC is also inhibited by Sec22b/ERS-24 antibodies. Morphologically, VSVG is transported from the ER to the Golgi apparatus via vesicular intermediates that scatter in the peripheral as well as the Golgi regions. In the presence of antibodies against Sec22b/ERS-24, VSVG is seen to accumulate in these intermediates, suggesting that Sec22b/ERS-24 functions at the level of the IC in ER-Golgi transport.
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PMID:Morphological and functional association of Sec22b/ERS-24 with the pre-Golgi intermediate compartment. 995 Jun 87

Adaptation of eukaryotic cells to changing environmental conditions entails rapid regulation of protein targeting and transport to specific organelles. Such adaptation is well exemplified in mammalian cells exposed to nitrogen starvation that are triggered to form and transport autophagosomes to lysosomes, thus constituting an inducible intracellular trafficking pathway. Here we investigated the relationship between the general secretory machinery and the autophagic pathway in Chinese hamster ovary cells grown in the absence of amino acid. Utilizing VSVG-YFP (vesicular stomatitis virus G protein fused to yellow fluorescent protein) and norepinephrine as markers for constitutive and regulated exocytosis, respectively, we found that secretion is attenuated in cells grown in media lacking amino acid. Such decrease in exocytosis stems from partial inhibition of N-ethylmaleimide-sensitive factor ATPase activity, which in turn causes an accumulation of SNARE complexes at both the Golgi apparatus and the plasma membrane of the starved cells. These findings expose a novel cellular strategy to attenuate secretion of proteins under conditions of limited amino acid supply.
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PMID:Modulation of N-ethylmaleimide-sensitive factor activity upon amino acid deprivation. 1570 57

It has been suggested that syntaxin 5 (Syx5) participates in vesicular transport. We examined the effects of Syx5 down-regulation on the morphology of the Golgi apparatus and the transport of vesicles in mammalian cells. Knockdown of the Syx5 gene resulted in Golgi fragmentation without changing the level of endoplasmic reticulum (ER)-resident proteins, other Golgi-SNAREs (soluble N-ethylmaleimide-sensitive factor-attachment protein receptors), and coatmer proteins. Strikingly, a major decrease in Syx5 expression barely affected the anterograde transport of vesicular stomatitis virus G (VSVG) protein to the plasma membrane. These results suggest that Syx5 is required for the maintenance of the Golgi structures but may not play a major role in the transport of vesicles carrying VSVG between the ER and the Golgi compartment.
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PMID:RNA interference-mediated silencing of the syntaxin 5 gene induces Golgi fragmentation but capable of transporting vesicles. 1608 Oct 76