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  • The EMBO Journal (2004) 23, 2059 - 2070
  • doi:10.1038/sj.emboj.7600159

Published online: 29 April 2004

Entry of newly synthesized GLUT4 into the insulin-responsive storage compartment is GGA dependent

Robert T Watson1,a, Ahmir H Khan2,a, Megumi Furukawa1,a, June Chunqiu Hou1, Lin Li3, Makoto Kanzaki1, Shuichi Okada4, Konstantin V Kandror3 and Jeffrey E Pessin1

  1. Department of Pharmacological Sciences, SUNY-Stony Brook, Stony Brook, NY, USA
  2. Department of Physiology & Biophysics, The University of Iowa, Iowa City, IA, USA
  3. Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
  4. Department of Medicine, Gunma University, Maebashi, Gunma, Japan

Correspondence to:

Jeffrey E Pessin, The Department of Pharmacological Sciences, SUNY-Stony Brook, Stony Brook, NY 11794-8651, USA. Tel.: +1 631 444 3059; Fax: +1 631 444 3022; E-mail: Pessin@pharm.sunysb.edu

aThese authors contributed equally to this study

Received 17 September 2003; Accepted 12 February 2004

Following biosynthesis, both GLUT1 and VSV-G proteins appear rapidly (2–3 h) at the plasma membrane, whereas GLUT4 is retained in intracellular membrane compartments and does not display any significant insulin responsiveness until 6–9 h. Surprisingly, the acquisition of insulin responsiveness did not require plasma membrane endocytosis, as expression of a dominant-interfering dynamin mutant (Dyn/K44A) had no effect on the insulin-stimulated GLUT4 translocation. Furthermore, expression of endocytosis-defective GLUT4 mutants or continuous surface labeling with an exofacial specific antibody demonstrated that GLUT4 did not transit the cell surface prior to the acquisition of insulin responsiveness. The expression of a dominant-interfering GGA mutant (VHS-GAT) had no effect on the trafficking of newly synthesized GLUT1 or VSV-G protein to the plasma membrane, but completely blocked the insulin-stimulated translocation of newly synthesized GLUT4. Furthermore, in vitro budding of GLUT4 vesicles but not GLUT1 or the transferrin receptor was inhibited by VHS-GAT. Together, these data demonstrate that following biosynthesis, GLUT4 directly sorts and traffics to the insulin-responsive storage compartment through a specific GGA-sensitive process.

  • Keywords:

    • biosynthesis,
    • GGA,
    • GLUT4,
    • insulin,
    • trafficking