Predicted to enable GTPase activator activity and guanyl-nucleotide exchange factor activity. Acts upstream of or within adult locomotory behavior; dendrite morphogenesis; and phosphatidylinositol 3-kinase signaling. Located in plasma membrane. Is expressed in brain ventricular layer and gut. Human ortholog(s) of this gene implicated in Klatskin's tumor. Orthologous to human PREX2 (phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 2). [provided by Alliance of Genome Resources, Apr 2022]