IMR Press / FBL / Volume 8 / Issue 4 / DOI: 10.2741/1137

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Regulation of GLUT4 traffic and function by insulin and contraction in skeletal muscle
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1 Department of Anatomy and Physiology, Lipid Research Unit, Laval University Hospital Research Center, Ste-Foy, Québec, G1V 4G2, Canada

Academic Editor: Konstantin Kandror

Front. Biosci. (Landmark Ed) 2003, 8(4), 1072–1084; https://doi.org/10.2741/1137
Published: 1 September 2003
(This article belongs to the Special Issue Insulin regulation of glucose transport)
Abstract

Glucose transport across the cell surface is a key regulatory step for glucose metabolism in skeletal muscle. Both insulin and exercise increase glucose transport into myofibers through glucose transporter (GLUT) proteins. Skeletal muscle expresses several members of the GLUT family but the GLUT4 glucose transporter is considered the main "regulatable" isoform that is modulated by insulin and contraction. Glucose transport rate can be stimulated either by recruitment of GLUT4 units from intracellular storage vesicles or through activation of cell surface transporters. Insulin activates GLUT4 translocation through a complex signaling cascade involving both the lipid kinase phosphatidylinositol 3-kinase and the proto-oncoprotein c-Cbl. Contraction, on the other hand, appears to trigger GLUT4 translocation at least in part through activation of the metabolite-sensing 5'-AMP-activated protein kinase. Furthermore, recent studies suggest that p38 MAP kinase activation represents a point of convergence of the signaling pathways utilized by insulin and contraction to increase GLUT4 activation at the cell surface. This review will summarize our current knowledge of these alternative pathways of GLUT4 regulation in skeletal muscle.

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