GTPase-activating protein for p21-rac. In the inactive state, the N terminus protrudes into the active site of the Rho-GAP domain, sterically blocking Rac binding. Phospholipid binding to the Phorbol-ester/DAG-type zinc-finger/C1 domain triggers the cooperative dissociation of these interactions, allowing the N-terminus to move out of the active site and thereby activating the enzyme (By similarity).