Enables GTPase activity. Acts upstream of or within several processes, including G1/S transition of mitotic cell cycle; Rac protein signal transduction; and regulation of cell shape. Predicted to be located in several cellular components, including Golgi apparatus; cell junction; and plasma membrane. Is expressed in several structures, including branchial pouch; cerebral cortex; ganglia; gut; and hair follicle. Orthologous to human RHOU (ras homolog family member U). [provided by Alliance of Genome Resources, Apr 2022]