GTP-bound forms of rab6 induce the redistribution of Golgi proteins into the endoplasmic reticulum.
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.
Martinez
O
O
Unité Mixte de Recherche, Institut Curie/Centre National de la Recherche Scientifique 144, Paris, France.
Antony
C
C
Pehau-Arnaudet
G
G
Berger
E G
EG
Salamero
J
J
Goud
B
B
D000595:Amino Acid Sequence; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D015415:Biomarkers; D020126:Brefeldin A; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000235:genetics; D006031:Glycosylation; D006056:Golgi Apparatus / Q000201:enzymology / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006367:HeLa Cells; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D006801:Humans; D037102:Lectins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D009237:N-Acetyllactosamine Synthase / Q000378:metabolism*; D037121:Plant Lectins; D014162:Transfection / Q000235:genetics; D020691:rab GTP-Binding Proteins; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
D000944:Antigens, Differentiation, B-Lymphocyte; D015415:Biomarkers; D002352:Carrier Proteins; D003517:Cyclopentanes; D000949:Histocompatibility Antigens Class II; D037102:Lectins; D037121:Plant Lectins; C094135:Rab6 protein; C045084:invariant chain; C043696:jacalin; D006153:Guanosine Diphosphate; D020126:Brefeldin A; D006160:Guanosine Triphosphate; D009237:N-Acetyllactosamine Synthase; D020691:rab GTP-Binding Proteins; D018631:ras Proteins