Enables GTPase inhibitor activity and small GTPase binding activity. Predicted to be involved in several processes, including Rho protein signal transduction; cytoskeleton-dependent cytokinesis; and septin ring organization. Predicted to act upstream of or within apoptotic process. Predicted to be located in cytosol. Predicted to be active in actomyosin contractile ring. Is expressed in several structures, including alimentary system; brain; hemolymphoid system gland; liver and biliary system; and reproductive system. Orthologous to human RTKN (rhotekin). [provided by Alliance of Genome Resources, Apr 2022]