Regulates clathrin-mediated endocytosis by phosphorylating the AP2M1/mu2 subunit of the adaptor protein complex 2 (AP-2) which ensures high affinity binding of AP-2 to cargo membrane proteins during the initial stages of endocytosis (PubMed:17494869, PubMed:11877457, PubMed:11877461, PubMed:12952931, PubMed:14617351, PubMed:25653444). Isoform 1 and isoform 2 display similar levels of kinase activity towards AP2M1 (PubMed:17494869). Preferentially, may phosphorylate substrates on threonine residues (PubMed:11877457, PubMed:18657069). Regulates phosphorylation of other AP-2 subunits as well as AP-2 localization and AP-2-mediated internalization of ligand complexes (PubMed:12952931). Phosphorylates NUMB and regulates its cellular localization, promoting NUMB localization to endosomes (PubMed:18657069). Binds to and stabilizes the activated form of NOTCH1, increases its localization in endosomes and regulates its transcriptional activity (PubMed:21464124). (Microbial infection) By regulating clathrin-mediated endocytosis, AAK1 plays a role in the entry of hepatitis C virus as well as for the lifecycle of other viruses such as Ebola and Dengue. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Stimulated by clathrin. Interacts (via CBD domain) with clathrin (PubMed:17494869, PubMed:14617351). Interacts with AP-2 complex (PubMed:17494869, PubMed:12952931, PubMed:14617351). Interacts with NUMB (PubMed:18657069). Interacts with alpha-adaptin (By similarity). Interacts with EPS15 isoform 2 (PubMed:21464124). Interacts with membrane-bound activated NOTCH1 but not with the inactive full-length form of NOTCH1 (PubMed:21464124). Preferentially interacts with monoubiquitinated activated NOTCH1 compared to the non-ubiquitinated form (PubMed:21464124). Active when found in clathrin-coated pits at the plasma membrane. In neuronal cells, enriched at presynaptic terminals. In non-neuronal cells, enriched at leading edge of migrating cells. Detected in brain, heart and liver. Isoform 1 is the predominant isoform in brain. Autophosphorylated. By regulating the entry of hepatitis C virus as well as the lifecycle of other viruses such as Ebola and Dengue, AAK1 is a potential drug target for developing antiviral therapies. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Extended N-terminus.