Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The carboxyl-terminal Lys-Asp-Glu-Leu (KDEL), or a closely-related sequence, is important for ER localization of both lumenal as well as type II membrane proteins. This sequence functions as a retrieval signal at post-ER compartment(s), but the exact compartment(s) where the retrieval occurs remains unresolved. With an affinity-purified antibody against the carboxyl-terminal sequence of the mammalian KDEL receptor, we have investigated its subcellular localization using immunogold labeling on thawed cryosections of different tissues, such as mouse spermatids and rat pancreas, as well as HeLa, Vero, NRK, and mouse L cells. We show that rab1 is an excellent marker of the intermediate compartment, and we use this marker, as well as budding profiles of the mouse hepatitis virus (MHV) in cells infected with this virus, to identify this compartment. Our results demonstrate that the KDEL receptor is concentrated in the intermediate compartment, as well as in the Golgi stack. Lower but significant labeling was detected in the rough ER. In general, only small amounts of the receptor were detected on the trans side of the Golgi stack, including the trans-Golgi network (TGN) of normal cells and tissues. However, some stress conditions, such as infection with vaccinia virus or vesicular stomatitis virus, as well as 20 degrees C or 43 degrees C treatment, resulted in a significant shift of the distribution towards the trans-TGN side of the Golgi stack. This shift could be quantified in HeLa cells stably expressing a TGN marker. No significant labeling was detected in structures distal to the TGN under all conditions tested. After GTP gamma S treatment of permeabilized cells, the receptor was detected in the beta-COP-containing buds/vesicles that accumulate after this treatment, suggesting that these vesicles may transport the receptor between compartments. We propose that retrieval of KDEL-containing proteins occurs at multiple post-ER compartments up to the TGN along the exocytotic pathway, and that within this pathway, the amounts of the receptor in different compartments varies according to physiological conditions.
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PMID:Localization of the Lys, Asp, Glu, Leu tetrapeptide receptor to the Golgi complex and the intermediate compartment in mammalian cells. 779 12

A serum from a patient with HBV hepatitis was found to contain autoantibodies reacting with various mammalian cells. Immunofluorescence staining of cultured cells with the autoantibodies revealed that the antigen was localized at perinuclear regions, where the Golgi markers alpha-mannosidase II and beta-COP were colocalized. The autoantigen disappeared from the perinuclear regions upon incubation with the fungal metabolite brefeldin A, and the immunostainable structures were fragmented into vesicles by treatment with nocodazole. These results strongly indicate that the antigen is localized at the Golgi complex. Immunoblots of cell lysates showed that the autoantibodies recognized a single protein with a molecular mass of 230 kDa in a variety of cell lines, indicating that the 230-kDa antigen is a conserved protein among mammalian species. We designated this protein GCP230 (Golgi complex-associated protein with a molecular mass of 230 kDa). when a postnuclear fraction was prepared and centrifuged, GCP230 was recovered in both cytosol and membrane fractions. Peripheral interaction of GCP230 with membranes was confirmed by phase separation in Triton X-114 solution and by extraction with sodium carbonate. Taken together, these results indicate that GCP230 is a peripheral membrane protein of the Golgi derived from the cytosol, although its function is not known at present.
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PMID:Identification and characterization of a 230-kDa Golgi-associated protein recognized by autoantibodies from a patient with HBV hepatitis. 872 75