Clathrin-coated vesicles, involved in endocytosis and Golgi processing, have a surface lattice containing clathrin triskelia and stoichiometric amounts of additional components termed assembly proteins, or APs. The AP form at the plasma membrane, AP2, is composed of two large subunits of 100-115 kDa, denoted AP2 alpha and AP2 beta, a medium chain of 50 kDa, designated AP50, and a small chain (1). The medium chain AP2 mu1 interacts specifically with the tyrosine-based signals of several integral membrane proteins through the consensus sequence YXXPhi, where X can be any residue and Phi is a large hydrophobic residue (2). Phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P(2)] is an important factor for a variety of cellular functions ranging from cell signaling to actin cytoskeletal dynamics and endocytic membrane traffic. It has been shown that the clathrin adaptor complex AP2 is a regulator of phosphatidylinositol 4-phosphate 5-kinase (PIPK)-mediated PI(4,5)P(2) synthesis. AP2 directly interacts with the kinase core domain of type I PIPK isozymes via its mu2-subunit in vitro and in native protein extracts (3).
Synonyms: AP2M1, CLAPM1, KIAA0109, AP-2 complex subunit mu, Adapter-related protein complex 2 mu subunit,Adaptor protein complex AP-2 subunit mu,Adaptin-mu2,AP-2 mu chain,Plasma membrane adaptor AP-2 50 kDa protein,HA2 50 kDa subunit,Clathrin assembly protein compl