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

Sadler, Jessica B.A. and Bryant, Nia J. and Gould, Gwyn W. (2015) Characterization of VAMP isoforms in 3T3-L1 adipocytes : implications for GLUT4 trafficking. Molecular Biology of the Cell, 26 (3). pp. 530-536. ISSN 1059-1524

[img]
Preview
Text (Sadler-etal-MBC-2014-Characterization-of-VAMP-isoforms-in-3T3-L1-adipocytes)
Sadler_etal_MBC_2014_Characterization_of_VAMP_isoforms_in_3T3_L1_adipocytes.pdf
Final Published Version
License: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 logo

Download (1MB)| Preview

    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.