AS160, the Akt substrate regulating GLUT4 translocation, has a functional Rab GTPase-activating protein domain

Cristinel P. Mîinea, Hiroyuki Sano, Susan Kane, Eiko Sano, Mitsunori Fukuda, Johan Peränen, William S. Lane, Gustav E. Lienhard

Research output: Contribution to journalArticlepeer-review

284 Citations (Scopus)

Abstract

Recently, we described a 160 kDa protein (designated AS 160, for Akt substrate of 160 kDa) with a predicted Rab GAP (GTPase-activating protein) domain that is phosphorylated on multiple sites by the protein kinase Akt. Phosphorylation of AS160 in adipocytes is required for insulin-stimulated translocation of the glucose transporter GLUT4 to the plasma membrane. The aim of the present study was to determine whether AS160 is in fact a GAP for Rabs, and, if so, what its specificity is. We first identified a group of 16 Rabs in a preparation of intracellular vesicles containing GLUT4 by MS. We then prepared the recombinant GAP domain of AS 160 and examined its activity against many of these Rabs, as well as several others. The GAP domain was active against Rabs 2 A, 8A, 10 and 14. There was no significant activity against 14 other Rabs. GAP activity was further validated by the finding that the recombinant GAP domain with the predicted catalytic arginine residue replaced by lysine was inactive. Finally, it was found by immunoblotting that Rabs 2A, 8A and 14 are present in GLUT4 vesicles. These results indicate that AS160 is a Rab GAP, and suggest novel Rabs that may participate in GLUT4 translocation.

Original languageEnglish
Pages (from-to)87-93
Number of pages7
JournalBiochemical Journal
Volume391
Issue number1
DOIs
Publication statusPublished - 2005 Oct 1
Externally publishedYes

Keywords

  • Akt
  • Akt substrate of 160kDa (AS160)
  • GLUT4
  • GTPase-activating protein (GAP)
  • Rab

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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