Characterization of VAMP isoforms in 3T3-L1 adipocytes: implications for GLUT4 trafficking

Jessica B.A. Sadler, Nia J. Bryant, Gwyn W. Gould

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Abstract

The fusion of GLUT4-containing vesicles with the plasma membrane of adipocytes is a key facet of insulin action. This process is mediated by the formation of functional soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes between the plasma membrane t-SNARE complex and the vesicle v-SNARE or VAMP. The t-SNARE complex consists of Syntaxin4 and SNAP23, and whereas many studies identify VAMP2 as the v-SNARE, others suggest that either VAMP3 or VAMP8 may also fulfil this role. Here we characterized the levels of expression, distribution, and association of all the VAMPs expressed in 3T3-L1 adipocytes to provide the first systematic analysis of all members of this protein family for any cell type. Despite our finding that all VAMP isoforms form SDS-resistant SNARE complexes with Syntaxin4/SNAP23 in vitro, a combination of levels of expression (which vary by >30-fold), subcellular distribution, and coimmunoprecipitation analyses lead us to propose that VAMP2 is the major v-SNARE involved in GLUT4 trafficking to the surface of 3T3-L1 adipocytes.

Original languageEnglish
Pages (from-to)530-536
Number of pages7
JournalMolecular Biology of the Cell
Volume26
Issue number3
Early online date10 Dec 2014
DOIs
Publication statusPublished - 1 Feb 2015

Keywords

  • vamp isoforms
  • 3T3-L1 adipocytes
  • GLUT4 trafficking

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