Potential role of 3-phosphoinositide-dependent protein kinase 1 (PDK1) in insulin-stimulated glucose transporter 4 translocation in adipocytes

Insulin stimulation of Glut 4 translocation requires the activation of phos phatidylinositol 3-kinase (PI 3-kinase) but the downstream pathway remains ill-defined. We demonstrated that the overexpression of PDK1 (3-phosphoinos itide-dependent protein kinase 1), a downstream effector of PI 3-kinase, st imulated Glut 4 translocation in adipocytes. This effect does not require t he PH domain of PDK1, but expression of the pleckstrin homology domain-dele ted PDK1 inhibits the effect of insulin, but not okadaic acid, on Glut 4 tr anslocation, These results support a role of the PDK1 pathway in the transm ission of insulin signal to Glut translocation. (C) 1999 Federation of Euro pean Biochemical Societies.