Activated type I phosphatidylinositol kinase is associated with the epidermal growth factor (EGF) receptor following EGF stimulation.

• DOI: 10.1073/pnas.87.10.3816
• Publication Date: 2006-05-31T11:19:43Z
• Authors: J D Bjorge; T O Chan; M Antczak; H J Kung; D J Fujita
• Keywords: 0301 basic medicine; Epidermal Growth Factor; Immunoblotting; Phosphotransferases; Transfection; Antibodies; Cell Line; Enzyme Activation; ErbB Receptors; Isoenzymes; Kinetics; 03 medical and health sciences; Animals; Humans; 1-Phosphatidylinositol 4-Kinase

We have shown that a type I phosphatidylinositol (PI) kinase activity is associated with the epidermal growth factor (EGF) receptor in a mouse fibroblast cell line expressing human EGF receptors (NRHER5) and that this activity increases dramatically upon treatment of cells with physiologically relevant concentrations of EGF. EGF stimulated a time-dependent increase in EGF receptor-associated PI kinase activity measured in EGF receptor immunoprecipitates. Activation was detected 15 min after the addition of EGF, and it peaked between 1 and 2 hr. Activation of PI kinase was detected with EGF concentrations as low as 10 pM and maximal stimulation occurred at approximately 1 nM. Analysis of deacylated PI phosphate products, and inhibition of the PI kinase activity by nonionic detergent, indicated that the PI kinase described here was type I or PI 3' kinase. These results demonstrate the regulation of a type I PI kinase by EGF and suggest a potential role in the EGF receptor signal transduction pathway.