AAK1(AP2 associated kinase 1) is a member of the SNF1 subfamily of serine/threonine protein kinases. AAK1 plays a significant role in receptor-mediated endocytosis, a process essential for cellular communication and nutrient uptake. This 961 amino acid protein, which belongs to the protein kinase superfamily and the serine/threonine protein kinase family, is encoded by a gene located on human chromosome 2p14. AAK1 is involved in ATP and nucleotide binding, protein serine/threonine kinase functions, and transferase activity, and specifically phosphorylates a subunit of the adaptor protein complex 2 (AP-2). This phosphorylation enhances the binding of AP-2 to sorting signals in membrane-bound receptors, thereby facilitating endocytosis. AAK1 contains a single protein kinase domain, and clathrin stimulates kinase activity, allowing AAK1 to exist in two alternatively spliced isoforms, which may have distinct regulatory roles in cellular processes.