Open AccessPeroxovanadate induces tyrosine phosphorylation of phosphoinositide‐dependent protein kinase‐1
Author(s) -
Grillo Sophie,
Grémeaux Thierry,
Casamayor Antonio,
Alessi Dario R,
Le MarchandBrustel Yannick,
Tanti JeanFrançois
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01759.x
Subject(s) - proto oncogene tyrosine protein kinase src , tyrosine phosphorylation , phosphorylation , sh2 domain , microbiology and biotechnology , wortmannin , tyrosine kinase , mitogen activated protein kinase kinase , protein kinase b , receptor tyrosine kinase , chemistry , biology , biochemistry , protein kinase a , signal transduction
Phosphoinositide‐dependent protein kinase‐1 (PDK1) is a recently identified kinase that phosphorylates and activates protein kinase B (PKB). Activation of PKB by insulin is linked to its translocation from the cytosol to the plasma membrane. However, no data are available yet concerning the localization of PDK1 in insulin‐sensitive tissue. Using isolated adipocytes, we studied the effect of insulin and of an insulin‐mimicking agent peroxovanadate on the subcellular localization of PDK1. In unstimulated adipocytes, overexpressed PDK1 was mostly cytosolic with a low amount associated to membranes. Peroxovanadate stimulation induced the redistribution of PDK1 to the membranes while insulin was without effect. This peroxovanadate effect was dependent on phosphatidylinositol 3,4,5 triphosphate [PtdIns(3,4,5) P 3 ] production as inhibition of PtdIns 3‐kinase by wortmannin or deletion of the PH domain of PDK1 prevented the peroxovanadate‐induced translocation of PDK1. Further, peroxovanadate‐treatment induced a tyrosine phosphorylation of PDK1 which was wortmannin insensitive and did not require the PH domain of PDK1. An inhibitor of Src kinase (PP2) decreased the peroxovanadate‐induced PDK1 tyrosine phosphorylation and overexpression of v‐Src stimulated this phosphorylation. Mutation of tyrosine 373 of PDK1 abolished the v‐Src induced PDK1 tyrosine phosphorylation and partially reduced the effect of peroxovanadate. Our findings suggest that PDK1 could be a substrate for tyrosine kinases and identify Src kinase as one of the tyrosine kinases able to phosphorylate PDK1.