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)

High-molecular-weight, asparagine-linked glycopeptides--the lactosaminoglycans--are the major class of protein-bound carbohydrates synthesized by F9 cells; these cells synthesize only minor amounts of smaller glycopeptides. In contrast, F9ACC19, an endodermal cell line derived from F9 cells, synthesizes only minor amounts of lactosaminoglycans and a high proportion of smaller glycopeptides. Biochemical analysis of the small glycopeptides from F9ACC19 cells revealed that they are larger, bind less efficiently to concanavalin-A Sepharose and contain more sialic acid than their counterparts from F9 cells. Both cell types contain a small proportion of high-mannose glycopeptides. When synthesized by F9ACC19 cells, the glycopeptides of vesicular stomatitis virus show a high level of sialylation as compared to those synthesized by F9 cells, where few or no sialic-acid residues are present; this shows that the differences observed in total glycopeptides reflect differences in the glycosylation machinery of the cells. Consistent with this observation, sialyltransferase activity in vitro using a variety of acceptors was found to be markedly higher in F9ACC19 than in F9 cells, while galactosyltransferase activity was reduced several fold in F9ACC19 cells. These data support the hypothesis that the increased sialyltransferase activity in endodermal differentiated F9ACC19 cells may block the terminal galactose residue of glycopeptides, thereby inhibiting the synthesis of lactosaminoglycans in these cells.
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PMID:Increased sialylation of complex glycopeptides during differentiation of mouse embryonal carcinoma cells. 392 74

Megalomicin (MGM) is a macrolide antibiotic which has been demonstrated previously to cause an anomalous glycosylation of viral proteins. Here we show that MGM produces profound alterations on Golgi morphology and function. The addition of MGM at 50 microM for 1 h caused a dilation of the Golgi detected by immunofluorescence staining for medial- and trans-Golgi markers. The effect of MGM was clearly more intense on the trans-side of the Golgi, as evidenced in electron microscope preparations. The effect on Golgi morphology was reversible and correlated with an impairment of glycoprotein processing in the trans-Golgi. Thus, although the vesicular stomatitis virus G protein was processed in the presence of MGM to an endoglycosidase H-resistant form, it was poorly sialylated. The sialylation of cellular proteins was also inhibited, resulting in cells with low level of sialylation on the cell surface. However MGM did not inhibit the activities of the galactosyl- or sialyltransferase as measured in vitro. MGM inhibited cis- to medial-, and more strongly, medial- to trans-Golgi transport of vesicular stomatitis virus G protein in an in vitro system, suggesting that the impairment in glycoprotein maturation observed in vivo is the result of intra-Golgi transport inhibition.
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PMID:Intra-Golgi transport inhibition by megalomicin. 863 86

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

GalT2 (UDP-Gal:GA2/GM2/GD2 beta-1,3-galactosyltransferase) is a Golgi-resident type II membrane protein that participates in the synthesis of glycosphingolipids. The molecular determinants for traffic and localization of this and other glycosyltransferases are still poorly characterized. Considering the possibility that interactions with other proteins may influence these processes, in the present study we carried out a yeast two-hybrid screening using elements of the N-terminal domain of GalT2 as bait. In this screening, we identified calsenilin and its close homologue CALP (calsenilin-like protein), both members of the recoverin-NCS (neuronal calcium sensor) family of calcium-binding proteins. In vitro, GalT2 binds to immobilized recombinant CALP, and CALP binds to immobilized peptides with the GalT2 cytoplasmic tail sequence. GalT2 and calsenilin interact physically when co-expressed in CHO (Chinese-hamster ovary)-K1 cells. The expression of CALP or calsenilin affect Golgi localization of GalT2, and of two other glycosyltransferases, SialT2 (CMP-NeuAc:GM3 sialyltransferase) and GalNAcT (UDP-GalNAc:lactosylceramide/GM3/GD3 beta1-4 N-acetylgalactosaminyltransferase), by redistributing them from the Golgi to the ER (endoplasmic reticulum), whereas the localization of the VSV-G (G-protein of the vesicular stomatitis virus) or the Golgin GM130 was essentially unaffected. Conversely, the expression of GalT2 affects the localization of calsenilin and CALP by shifting a fraction of the molecules from being mostly diffuse in the cytosol, to clustered structures in the perinuclear region. These combined in vivo and in vitro results suggest that CALP and calsenilin are involved in the trafficking of Golgi glycosyltransferases.
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PMID:Calsenilin and CALP interact with the cytoplasmic tail of UDP-Gal:GA2/GM2/GD2 beta-1,3-galactosyltransferase. 1826 47