protein kinase C conserved region 1 (C1 domain) found in beta-chimaerin and similar proteins
Beta-chimaerin, also called beta-chimerin (BCH) or Rho GTPase-activating protein 3 (ARHGAP3), is a GTPase-activating protein (GAP) 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. Beta-chimaerin contains a functional SH2 domain that can bind to phosphotyrosine motifs within receptors, a GAP domain with specificity in vitro for Rac1 and a diacylglycerol (DAG)-binding C1 domain which allows them to translocate to membranes in response to DAG signaling and anchors them in close proximity to activated Rac. This model corresponds to the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.