GTPase-activating protein for the ADP ribosylation factor family (Potential). Binds phosphatidylinositol 3,4,5-trisphosphate (PtdInsP3) and inositol 1,3,4,5-tetrakisphosphate (InsP4). Possesses a stoichiometry of two binding sites for InsP4 with identical affinity. Constitutively associated with the plasma membrane. Excluded from the nucleus. Highly expressed in placenta, spleen, kidney, skeletal muscle and adrenal gland. Weakly expressed in thyroid, liver, heart, lung, small intestine, peripheral blood leukocytes. Not detected in spinal cord, brain, stomach, trachea, colon, lymph node and bone marrow. May be due to a competing acceptor splice site.