Regulation of endocytosis by phosphatidylinositol 4,5-bisphosphate and ENTH proteins.

Clathrin-mediated endocytosis starts by a recruitment of endocytic proteins to the plasma membrane to induce invagination of lipid bilayer and subsequent vesicule formation. The recruitment of these components requires PtdIns(4,5)P2, a phosphoinositide on the plasma membrane. Although it is well known that the synthesis as well as the disruption of this lipid is important, recent studies have revealed the indispensable roles of direct interaction between PtdIns(4,5)P2 and the endocytic machinery. The ENTH domain is a newly found PtdIns(4,5)P2 binding unit conserved among endocytic proteins like epsins, AP180, and the Hip1/Sla2 family. This review focuses on the essential roles of PtdIns(4,5)P2 and its specific binding partner, the ENTH domain, in clathrin-mediated endocytosis.