title: A synthetic peptide corresponding to the Rab4 hypervariable carboxyl-terminal domain inhibits insulin action on glucose transport in rat adipocytes.
abstract: The present study was conducted to examine the involvement of Rab4, a low molecular weight GTP-binding protein, in the action of insulin on glucose transport. A synthetic peptide corresponding to the Rab4 hypervariable carboxyl-terminal domain, Rab4-(191-210), was successfully transferred into rat adipocytes by electroporation and inhibited insulin-stimulated glucose transport by about 50% without affecting the basal transport activity. In contrast, synthetic peptides corresponding to the Rab3C and Rab3D carboxyl-terminal hypervariable domain had little effect on insulin action on glucose transport. The Rab4-(191-210) peptide also reduced insulin-induced GLUT4 translocation from the intracellular pool to the plasma membrane. Furthermore, the Rab4-(191-210) peptide reduced both insulin-induced glucose transport and GLUT4 translocation in the presence of a major histocompatibility complex class I antigen-derived peptide, D(k)-(62-85), which is a potent inhibitor of GLUT4 internalization, suggesting that the peptide inhibited exocytotic recruitment of GLUT4-containing vesicles. The Rab4-(191-210) peptide also inhibited GTP gamma S-stimulated glucose transport. In addition, insulin-stimulated glucose transport was inhibited by the addition of anti-Rab4 antibody. These results suggest that Rab4 protein plays a crucial role in insulin action on GLUT4 translocation, especially in exocytotic recruitment by the hormone of the glucose transporter to the plasma membrane from the intracellular retention pool.
authors.affiliation: Department of Cell Biologoy, Institute for Molecular and Celluar Regulation, Gunma University, Maebashi, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shibata
authors.forename: W
authors.initials: W
authors.lastname: Omata
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Tanaka
authors.forename: I
authors.initials: I
authors.lastname: Kojima
mesh_terms: D019325:3-O-Methylglucose; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001692:Biological Transport / Q000187:drug effects; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D004822:Epididymis; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D051275:Glucose Transporter Type 4; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D007074:Immunoglobulin G / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D007329:Insulin Antagonists / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008757:Methylglucosides / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000187:drug effects / Q000378:metabolism*; D009124:Muscle Proteins; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D020695:rab4 GTP-Binding Proteins
chemical_list: D000906:Antibodies; D051275:Glucose Transporter Type 4; D007074:Immunoglobulin G; D007328:Insulin; D007329:Insulin Antagonists; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D010446:Peptide Fragments; C495693:Slc2a4 protein, mouse; C495694:Slc2a4 protein, rat; C099278:rab4 GTP-binding protein (191-210); D019325:3-O-Methylglucose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins