Abstract
rab6 is a ubiquitous ras-like GTPase involved in intra-Golgi transport. We have studied at both morphological and biochemical levels the behavior of Golgi resident proteins in HeLa cells overexpressing wild-type rab6 and GTP- and GDP-bound mutants of rab6 (rab6 Q72L and rab6 T27N, respectively). We show that wild-type rab6 and rab6 Q72L overexpression induces the redistribution of the trans-Golgi protein beta-1,4-galactosyltransferase into the endoplasmic reticulum (ER) and allows the addition of sialylated O-glycans on an ER-retained protein, the major histocompatibility complex class II-associated invariant chain. Remarkably, rab6 Q72L effects, which require the integrity of microtubules, were almost indistinguishable from those induced by brefeldin A, a fungic metabolite that causes a mixing of Golgi and ER membranes. In contrast, overexpression of rab6 T27N does not cause the redistribution of Golgi proteins, but inhibits basal O-glycosylation of the major histocompatibility complex class II-associated invariant chain.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Antigens, Differentiation, B-Lymphocyte / metabolism*
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Biomarkers
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Brefeldin A
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cyclopentanes / pharmacology
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Endoplasmic Reticulum / metabolism*
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Fluorescent Antibody Technique
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Gene Expression Regulation / genetics
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Glycosylation
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Golgi Apparatus / enzymology
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Golgi Apparatus / metabolism*
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Guanosine Diphosphate / metabolism
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Guanosine Triphosphate / metabolism*
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HeLa Cells
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Histocompatibility Antigens Class II / metabolism*
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Humans
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Lectins / metabolism
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Microtubules / metabolism
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Molecular Sequence Data
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N-Acetyllactosamine Synthase / metabolism*
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Plant Lectins*
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Transfection / genetics
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rab GTP-Binding Proteins*
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ras Proteins / genetics
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ras Proteins / metabolism*
Substances
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Antigens, Differentiation, B-Lymphocyte
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Biomarkers
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Carrier Proteins
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Cyclopentanes
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Histocompatibility Antigens Class II
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Lectins
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Plant Lectins
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Rab6 protein
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invariant chain
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jacalin
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Guanosine Diphosphate
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Brefeldin A
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Guanosine Triphosphate
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N-Acetyllactosamine Synthase
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rab GTP-Binding Proteins
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ras Proteins