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)

Inhibition of vesicular stomatitis virus (VSV) replication in LB cells by interferon (IFN) resembles the action of IFN on some retroviruses, in that the incorporation of glycoprotein into virions is defective. Primary amines added between 1 and 2 h post-infection significantly enhanced (five- to 1000-fold) the antiviral activity of IFN against VSV, but no enhancement of the antiviral activity of IFN against encephalomyocarditis virus, a virus with no membrane component, by primary amines was seen. SDS-PAGE and immunofluorescence analysis of viral proteins, and Nycodenz gradient fractionation, suggested that both IFN and primary amines inhibited the transport of VSV glycoprotein (G) to the plasma membrane; instead, G accumulated in the trans-Golgi network (TGN). Using sensitive intracellular pH (pHi) indicators, we found that IFN treatment significantly raised the pHi. A further increase in pHi was seen with a combination of IFN and primary amines; the increase in pHi correlated with an enhancement of the antiviral activity of IFN by primary amines. Amiloride inhibited the IFN-induced increase in pHi and a concomitant increase in the concentration of Na+ ions; this observation suggested that IFN induced cytoplasmic alkalinization by activating an Na+/H+ antiporter system. These results indicated that the IFN-induced increase in pHi may be responsible for the accumulation of G in the TGN, thereby producing G-deficient virus particles with reduced infectivity.
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PMID:Primary amines enhance the antiviral activity of interferon against a membrane virus: role of intracellular pH. 165 74

A fibroblast mutant cell line lacking the Na+/H+ antiporter was used to study the influence of low cytoplasmic pH on membrane transport in the endocytic and exocytic pathways. After being loaded with protons, the mutant cells were acidified at pH 6.2 to 6.8 for 20 min while the parent cells regulated their pH within 1 min. Cytoplasmic acidification did not affect the level of intracellular ATP or the number of clathrin-coated pits at the cell surface. However, cytosolic acidification below pH 6.8 blocked the uptake of two fluid phase markers, Lucifer Yellow and horseradish peroxidase, as well as the internalization and the recycling of transferrin. When the cytoplasmic pH was reversed to physiological values, both fluid phase endocytosis and receptor-mediated endocytosis resumed with identical kinetics. Low cytoplasmic pH also inhibited the rate of intracellular transport from the Golgi complex to the plasma membrane. This was shown in cells infected by the temperature-sensitive mutant ts 045 of the vesicular stomatitis virus (VSV) using as a marker of transport the mutated viral membrane glycoprotein (VSV-G protein). The VSV-G protein was accumulated in the trans-Golgi network (TGN) by an incubation at 19.5 degrees C and was transported to the cell surface upon shifting the temperature to 31 degrees C. This transport was arrested in acidified cells maintained at low cytosolic pH and resumed during the recovery phase of the cytosolic pH. Electron microscopy performed on epon and cryo-sections of mutant cells acidified below pH 6.8 showed that the VSV-G protein was present in the TGN. These results indicate that acidification of the cytosol to a pH less than 6.8 inhibits reversibly membrane transport in both endocytic and exocytic pathways. In all likelihood, the clathrin and nonclathrin coated vesicles that are involved in endo- and exocytosis cannot pinch off from the cell surface or from the TGN below this critical value of internal pH.
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PMID:Low cytoplasmic pH inhibits endocytosis and transport from the trans-Golgi network to the cell surface. 291 22