RhoGAP_ARHGAP20: RhoGAP (GTPase-activator protein [GAP] for Rho-like small GTPases) domain of ArhGAP20-like proteins. ArhGAP20, also known as KIAA1391 and RA-RhoGAP, contains a RhoGAP, a RA, and a PH domain, and ANXL repeats. ArhGAP20 is activated by Rap1 and induces inactivation of Rho, which in turn leads to neurite outgrowth. 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.