Syntaxin 4, VAMP2, and/or VAMP3/cellubrevin are functional target membrane and vesicle SNAP receptors for insulin-stimulated GLUT4 translocation in adipocytes.
Introduction of the cytoplasmic domain of syntaxin 4, using either recombinant vaccinia virus or single-cell microinjection, resulted in an inhibition of insulin-stimulated GLUT4 but not GLUT1 translocation to the plasma membrane. This was specific for syntaxin 4, since neither the expression of syntaxin 3 nor the expression of a syntaxin 4 mutant in which the vesicle-associated membrane protein (VAMP) binding site was deleted had any significant effect. Consistent with the requirement for a functional VAMP binding site, expression of the cytoplasmic domains of VAMP2 or VAMP3/cellubrevin also resulted in an inhibition of insulin-stimulated GLUT4 translocation. In addition, immunoprecipitation of the expressed syntaxin 4 cytoplasmic domain resulted in an insulin-stimulated increase in the coimmunoprecipitation of GLUT4-containing vesicles. Together, these data demonstrate that syntaxin 4, VAMP2, and/or VAMP3/cellubrevin can function as target membrane and vesicle SNAP receptors, respectively, for insulin-responsive GLUT4 translocation to the plasma membrane.
Olson
A L
AL
Department of Physiology & Biophysics, University of Iowa, Iowa City 52242-1109, USA.
Knight
J B
JB
Pessin
J E
JE
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008845:Microinjections; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D050765:Qa-SNARE Proteins; D050683:R-SNARE Proteins; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000494:pharmacology; D050600:SNARE Proteins; D014616:Vaccinia virus; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins
D051275:Glucose Transporter Type 4; D007328:Insulin; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; D050683:R-SNARE Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; C495693:Slc2a4 protein, mouse; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins