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)

The influenza virus A/Japan/305/57 hemagglutinin (HA) can be converted from a protein that is essentially excluded from coated pits into one that is internalized at approximately the rate of uptake of bulk membrane by replacing the HA transmembrane and cytoplasmic sequences with those of either of two other glycoproteins (Roth et al., 1986. J. Cell Biol. 102:1271-1283). To identify more precisely the foreign amino acid sequences responsible for this change in HA traffic, DNA sequences encoding the transmembrane (TM) or cytoplasmic (CD) domains of either the G glycoprotein of vesicular stomatitis virus (VSV) or the gC glycoprotein of herpes simplex virus were exchanged for those encoding the analogous regions of wild type HA (HA wt). HA-HA-G and HA-HA-gC, chimeras that contain only a foreign CD, resembled HA wt in having a long residence on the cell surface and were internalized very slowly. HA-HA-gC was indistinguishable from HA in our assays, whereas twice as much HA-HA-G was internalized as was HA wt. However, HA-G-HA, containing only a foreign TM, was internalized as efficiently as was HA-G-G, a chimeric protein with transmembrane and cytoplasmic sequences of VSV G protein. Conditions that blocked internalization through coated pits also inhibited endocytosis of the chimeric proteins. Although the external domains of the chimeras were less well folded than that of the wild type HA, denaturation of the wild type HA external domain by treatment with low pH did not increase the interaction of HA with coated pits. However, mutation of four amino acids in the TM of HA allowed the protein to be internalized, indicating that the property that allows HA to escape endocytosis resides in its TM. These results indicate that possession of a cytoplasmic recognition feature is not required for the internalization of all cell surface proteins and suggest that multiple mechanisms for internalization exist that operate at distinctly different rates.
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PMID:Endocytosis of chimeric influenza virus hemagglutinin proteins that lack a cytoplasmic recognition feature for coated pits. 870 20

Rab8 is a small Ras-like GTPase that regulates polarized membrane transport to the basolateral membrane in epithelial cells and to the dendrites in neurons. It has recently been demonstrated that fibroblasts sort newly synthesized proteins into two different pathways for delivery to the cell surface that are equivalent to the apical and the basolateral post-Golgi routes in epithelial cells (Yoshimori, T., P. Keller, M.G. Roth, and K. Simons. 1996. J. Cell Biol. 133:247-256). To determine the role of Rab8 in fibroblasts, we used both transient expression systems and stable cell lines expressing mutant or wild-type (wt) Rab8. A dramatic change in cell morphology occurred in BHK cells expressing both the wt Rab8 and the activated form of the GTPase, the Rab8Q67L mutant. These cells formed processes as a result of a reorganization of both their actin filaments and microtubules. Newly synthesized vesicular stomatitis virus G glycoprotein, a basolateral marker protein in MDCK cells, was preferentially delivered into these cell outgrowths. Based on these findings, we propose that Rab8 provides a link between the machinery responsible for the formation of cell protrusions and polarized biosynthetic membrane traffic.
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PMID:Rab8 promotes polarized membrane transport through reorganization of actin and microtubules in fibroblasts. 885 70