Activation of the glucose transporter GLUT4 by insulin.
The transport of glucose into cells and tissues is a highly regulated process, mediated by a family of facilitative glucose transporters (GLUTs). Insulin-stimulated glucose uptake is primarily mediated by the transporter isoform GLUT4, which is predominantly expressed in mature skeletal muscle and fat tissues. Our recent work suggests that two separate pathways are initiated in response to insulin: (i) to recruit transporters to the cell surface from intracellular pools and (ii) to increase the intrinsic activity of the transporters. These pathways are differentially inhibited by wortmannin, demonstrating that the two pathways do not operate in series. Conversely, inhibitors of p38 mitogen-activated protein kinase (MAPK) imply that p38 MAPK is involved only in the regulation of the pathway leading to the insulin-stimulated activation of GLUT4. This review discusses the evidence for the divergence of GLUT4 translocation and activity and proposed mechanisms for the regulation of GLUT4.
Furtado
L Michelle
LM
Programme in Cell Biology, Hospital for Sick Children, University of Toronto, ON, Canada.
Somwar
Romel
R
Sweeney
Gary
G
Niu
Wenyan
W
Klip
Amira
A
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D009004:Monosaccharide Transport Proteins / Q000502:physiology*; D009124:Muscle Proteins; D010766:Phosphorylation; D021381:Protein Transport; D015398:Signal Transduction; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases
D000730:Androstadienes; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; D000077191:Wortmannin