AAK1: Proteins and Enzymes

AP2-associated protein kinase 1 (AAK1) is a 100 kDa intracellular kinase that binds and phosphorylates NUMB and the mu2 subunit of AP2. NUMB and AP2 are adaptor proteins which are involved in the assembly and sorting of clathrin coated pits during receptor-mediated endocytosis. AAK1 contains one catalytic domain (aa 46-315) and a C-terminal clathrin-binding region. Alternate splicing of human AAK1 generates a 145 kDa long isoform that contains an additional clathrin-binding domain.