INSULIN-INDUCED TRANSLOCATION OF PROTEIN-KINASE-B TO THE PLASMA-MEMBRANE IN RAT ADIPOCYTES

Protein kinase B (PKB) has previously been shown to be activated in re sponse to insulin and growth factor stimulation. The activation mechan ism has been suggested to involve translocation of PKB to membranes, w here it is phosphorylated and activated. Insulin-induced translocation of PKB has not been demonstrated in a physiological target cell. Ther efore we have used the primary rat adipocyte to investigate insulin-in duced translocation of PKB. In the presence of 1 nM insulin translocat ion of PKB was detected within 30 seconds and was blocked by wortmanni n, a selective phosphatidylinositol 3-kinase inhibitor. This transloca tion was potentiated by the tyrosine phosphatase inhibitor vanadate. S ubcellular localization studies revealed that PKB translocated to the plasma membrane. (C) 1998 Academic Press.