ASAP2 is a multidomain protein belonging to the beta family with two ANK repeats, an Arf-GAP domain, a PH domain and a SH3 domain. This protein localizes in the Golgi apparatus and also at the plasma membrane where it colocalizes with protein tyrosine kinase 2-beta (PYK2) and forms a stable complex with PYK2 in vivo. ASAP2 is tyrosine phosphorylated by activated PYK2. It functions as a substrate and downstream target for PYK2 and SRC, a pathway that may be involved in the regulation of vesicular transport. ASAP2 activates the small GTPases ARF1, ARF5 and ARF6 and regulates the formation of post-Golgi vesicles and modulates constitutive secretion. It modulates phagocytosis mediated by Fc gamma receptor and ARF6. Usually detected in heart, brain, placenta, kidney, monocytes and pancreas, it is up-regulated during monocyte maturation. Multiple transcript variants encoding different isoforms have been found.