RhoGAP_PARG1: RhoGAP (GTPase-activator protein [GAP] for Rho-like small GTPases) domain of PARG1 (PTPL1-associated RhoGAP1). PARG1 was originally cloned as an interaction partner of PTPL1, an intracellular protein-tyrosine phosphatase. PARG1 interacts with Rap2, also a member of the Ras small GTPase superfamily whose exact function is unknown, and shows strong preference for Rho. Small GTPases cluster into distinct families, and all act as molecular switches, active in their GTP-bound form but inactive when GDP-bound. The Rho family of GTPases activates effectors involved in a wide variety of developmental processes, including regulation of cytoskeleton formation, cell proliferation and the JNK signaling pathway. GTPases generally have a low intrinsic GTPase hydrolytic activity but there are family-specific groups of GAPs that enhance the rate of GTP hydrolysis by several orders of magnitude.