RhoGAP_MgcRacGAP: RhoGAP (GTPase-activator protein [GAP] for Rho-like small GTPases) domain present in MgcRacGAP proteins. MgcRacGAP plays an important dual role in cytokinesis: i) it is part of centralspindlin-complex, together with the mitotic kinesin MKLP1, which is critical for the structure of the central spindle by promoting microtuble bundling. ii) after phosphorylation by aurora B MgcRacGAP becomes an effective regulator of RhoA and plays an important role in the assembly of the contractile ring and the initiation of cytokinesis. MgcRacGAP-like proteins contain a N-terminal C1-like domain, and a C-terminal RhoGAP domain. 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.