Regulates mbt kinase activity and is also required to recruit mbt to adherens junctions. Together with mbt, regulates photoreceptor cell morphogenesis (By similarity). Highly expressed in the adult unfed gut, expression drops after feeding. Expressed throughout development with highest levels in early embryo and pupae and lowest levels in late pupae and adults. Belongs to the small GTPase superfamily. Rho family. CDC42 subfamily.