GTPase-activating protein for the ADP ribosylation factor family (Potential). Binds phosphatidylinositol 4,5-bisphosphate, phosphatidylinositol 3,4,5-trisphosphate (PtdInsP3) and inositol 1,3,4,5-tetrakisphosphate (InsP4). Binding of phosphatidylinositol 3,5-bisphosphate and phosphatidylinositol 3,4-bisphosphate occurs at a much lower affinity. Possesses a stoichiometry of two binding sites for InsP4 with identical affinity (By similarity). Constitutively associated with the plasma membrane. Excluded from the nucleus (By similarity). Expressed in many tissues, with highest levels in fat, heart and skeletal muscle. Also detected in kidney, liver and lung.