GTPase-activating protein for p21-rac. Insufficient expression of beta-2 chimaerin is expected to lead to higher Rac activity and could therefore play a role in the progression from low-grade to high-grade tumors. 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. Highest levels in the brain and pancreas. Also expressed in the heart, placenta, and weakly in the kidney and liver. Expression is much reduced in the malignant gliomas, compared to normal brain or low-grade astrocytomas.