title: Transient effect of platelet-derived growth factor on GLUT4 translocation in 3T3-L1 adipocytes.
abstract: We earlier developed a novel method to detect translocation of the glucose transporter (GLUT) directly and simply using c-MYC epitope-tagged GLUT (GLUTMYC). To define the effect of platelet-derived growth factor (PDGF) on glucose transport in 3T3-L1 adipocytes, we investigated the PDGF- and insulin-induced glucose uptake, translocation of glucose transporters, and phosphatidylinositol (PI) 3-kinase activity in 3T3-L1, 3T3-L1GLUT4MYC, and 3T3-L1GLUT1MYC adipocytes. Insulin and PDGF stimulated glucose uptake by 9-10- and 5.5-6.5-fold, respectively, in both 3T3-L1 and 3T3-L1GLUT4MYC adipocytes. Exogenous GLUT4MYC expression led to enhanced PDGF-induced glucose transport. In 3T3-L1GLUT4MYC adipocytes, insulin and PDGF induced an 8- and 5-fold increase in GLUT4MYC translocation, respectively, determined in a cell-surface anti-c-MYC antibody binding assay. This PDGF-induced GLUT4MYC translocation was further demonstrated with fluorescent detection. In contrast, PDGF stimulated a 2-fold increase of GLUT1MYC translocation and 2.5-fold increase of glucose uptake in 3T3-L1GLUT1MYC adipocytes. The PDGF-induced GLUT4MYC translocation, glucose uptake, and PI 3-kinase activity were maximal (100%) at 5-10 min and thereafter rapidly declined to 40, 30, and 12%, respectively, within 60 min, a time when effects of insulin were maximal. Wortmannin (0.1 microM) abolished PDGF-induced GLUT4MYC translocation and glucose uptake in 3T3-L1GLUT4MYC adipocytes. These results suggest that PDGF can transiently trigger the translocation of GLUT4 and stimulate glucose uptake by translocation of both GLUT4 and GLUT1 in a PI 3-kinase-dependent signaling pathway in 3T3-L1 adipocytes.
authors.affiliation: Division of Molecular Genetics, Institute for Enzyme Research, The University of Tokushima, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Ebina
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*
chemical_list: D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D010982:Platelet-Derived Growth Factor; C495678:Slc2a1 protein, mouse; C495693:Slc2a4 protein, mouse; D019869:Phosphatidylinositol 3-Kinases; D005947:Glucose