Characterization of the role of the Rab GTPase-activating protein AS160 in insulin-regulated GLUT4 trafficking

Mark Larance, Georg Ramm, Jacqueline Stockli, Ellen M van Dam, Stephanie Winata, Valerie Wasinger, Fiona Simpson, Michael Graham, Jagath R Junutula, Michael Guilhaus, David E James

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302 Citations (Scopus)

Abstract

Insulin stimulates the translocation of the glucose transporter GLUT4 from intracellular vesicles to the plasma membrane. In the present study we have conducted a comprehensive proteomic analysis of affinity-purified GLUT4 vesicles from 3T3-L1 adipocytes to discover potential regulators of GLUT4 trafficking. In addition to previously identified components of GLUT4 storage vesicles including the insulin-regulated aminopeptidase insulin-regulated aminopeptidase and the vesicle soluble N-ethylmaleimide factor attachment protein (v-SNARE) VAMP2, we have identified three new Rab proteins, Rab10, Rab11, and Rab14, on GLUT4 vesicles. We have also found that the putative Rab GTPase-activating protein AS160 (Akt substrate of 160 kDa) is associated with GLUT4 vesicles in the basal state and dissociates in response to insulin. This association is likely to be mediated by the cytosolic tail of insulin-regulated aminopeptidase, which interacted both in vitro and in vivo with AS160. Consistent with an inhibitory role of AS160 in the basal state, reduced expression of AS160 in adipocytes using short hairpin RNA increased plasma membrane levels of GLUT4 in an insulin-independent manner. These findings support an important role for AS160 in the insulin regulated trafficking of GLUT4.
Original languageEnglish
Pages (from-to)37803 - 37813
Number of pages11
JournalJournal of Biological Chemistry
Volume280
Issue number45
Publication statusPublished - 2005
Externally publishedYes

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