Association of acyl-CoA synthetase-1 with GLUT4-containing vesicles
Program in Molecular Medicine and the Department of Biochemistry and Molecular Biology
Acyl Coenzyme A; Adipocytes; Amino Acid Sequence; Animals; Coenzyme A Ligases; Glucose Transporter Type 4; Male; Membrane Fusion; Microscopy, Electron; Monosaccharide Transport Proteins; *Muscle Proteins; Rats; Rats, Sprague-Dawley; *Repressor Proteins; *Saccharomyces cerevisiae Proteins
Life Sciences | Medicine and Health Sciences
GLUT4, the glucose transporter present in insulin-sensitive tissues, resides in intracellular vesicular structures and translocates to the cell surface in response to insulin. In an attempt to identify proteins present in these structures, GLUT4-enriched vesicles prepared from rat adipocytes treated with or without insulin were prepared by sucrose velocity gradient centrifugation and immunoadsorbed with anti-GLUT4 antibody. We report here the sequence identification by high performance liquid chromatography-ion trap mass spectrometry of a p75 protein band, long chain acyl-CoA synthetase-1, specifically present in immunoadsorbed GLUT4-containing vesicles but not in vesicles adsorbed by nonimmune serum. Acyl-CoA synthetase activity detected in GLUT4-enriched vesicles prepared by gradient centrifugation from insulin-treated adipocytes was decreased to about the same extent as GLUT4 protein. Additionally, immunoadsorbed GLUT4 vesicles were found to catalyze palmitoylation of proteins when incubated with labeled palmitate, a pathway that requires palmitate esterification with CoA. These data indicate that the insulin-sensitive membrane compartment that sequesters GLUT4 in fat cells contains long chain acyl-CoA synthetase-1 and its product fatty acyl-CoA, shown previously to be required for budding and fusion in membrane trafficking processes.
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Citation: J Biol Chem. 1998 Feb 6;273(6):3132-5.
The Journal of biological chemistry
Sleeman, Mark W.; Donegan, Niles P.; Heller-Harrison, Robin A.; Lane, William S.; and Czech, Michael P., "Association of acyl-CoA synthetase-1 with GLUT4-containing vesicles" (1998). Open Access Articles. 783.