Phosphatidylinositol-4-phosphate 5-Kinase-1β Is Essential for Epidermal Growth Factor Receptor-mediated Endocytosis

Abstract

Phosphatidylinositol-4,5-bisphosphate (PIP2) is known to play an important role in signal transduction and membrane trafficking. We show that one enzyme responsible for PIP2 production, phosphatidylinositol-4-phosphate 5-kinase type 1β (PIPKβ), is essential for epidermal growth factor receptor (EGFR)-mediated endocytosis. Expression of murine PIPKβ in NR6 cells expressing EGFR strikingly increased receptor internalization. Moreover, the kinase was shown to form an immunoprecipitable complex with EGFR. Expression of either a truncated kinase or a kinase dead mutant inhibited EGFR endocytosis and also blocked the membrane recruitment of PIPKβ and both clathrin light chain and dynamin. Our results delineate a novel mechanism by which PIPKβ regulates receptor-mediated endocytosis and receptor tyrosine kinase membrane traffic.