Rho GTPase Activating Protein 9 (ARHGAP9)

Rho GTPase-activating protein 9 is a member of the Rho-GAP family of GTPase activating proteins. The protein has substantial GAP activity towards several Rho-family GTPases in vitro, converting them to an inactive GDP-bound state. It is implicated in regulating adhesion of hematopoietic cells to the extracellular matrix. Multiple transcript variants encoding different isoforms have been found for this gene.The deduced 731-amino acid protein contains an N-terminal SH3 domain, followed by a WW domain, a pleckstrin homology domain, and a C-terminal GAP domain. Northern blot analysis detected a 2.6-kb transcript in peripheral blood, spleen, and thymus only. By phylogenetic analysis, Peck et al. (2002) determined that the GAP domain of ARHGAP9 is most closely related to the GAP domain of ARHGAP12.