Akt-2 binds to Glut4-containing vesicles and phosphorylates their component proteins in response to insulin

Glut4-containing vesicles immunoadsorbed from primary rat adipocytes posses s endogenous protein kinase activity and phosphorylation substrates. Phosph orylation of several vesicle proteins including Glut4 itself is rapidly act ivated by insulin. Wortmannin blocks the effect of insulin when added to ce lls in vivo prior to insulin administration. By means of MonoQ chromatograp hy and Western blot analysis, vesicle-associated protein kinase is identifi ed as Akt-2, a lipid-binding protein kinase involved in insulin signaling. Akt-2 is found to be recruited to Glut4-containing vesicles in response to insulin.