THE PROTEIN-KINASE-C PSEUDOSUBSTRATE PEPTIDE (PKC19-36) INHIBITS INSULIN-STIMULATED PROTEIN-KINASE ACTIVITY AND INSULIN-MEDIATED TRANSLOCATION OF THE GLUCOSE-TRANSPORTER GLUT-4 IN STREPTOLYSIN-O PERMEABILIZED ADIPOCYTES

The effect of insulin on protein kinase activity and plasma membrane t ranslocation of the glucose transporter GLUT 4 has been studied in adi pocytes permeabilized by Streptolysin-O. Insulin increased protein kin ase activity, and this was completely inhibited by the PKC pseudosubst rate inhibitor peptide (PKC19-36). Insulin-mediated translocation of G LUT 4 was also inhibited by the PKC inhibitor peptide. Both these insu lin effects were blocked by a PKCbeta neutralizing antibody. Our resul ts are consistent with the hypothesis that insulin activates PKCbeta a ctivity in adipocytes in situ, and that this PKC activation is a compo nent of the system whereby insulin regulates translocation of GLUT 4 t o the plasma membrane. (C) 1997 Federation of European Biochemical Soc ieties.