GTP-binding protein involved in protein trafficking; may modulate vesicle budding and uncoating within the Golgi apparatus. Interacts (when activated) with GGA1, GGA2 and GGA3; the interaction is required for proper subcellular location of GGA1, GGA2 and GGA3 (By similarity). Binds ASAP2 (By similarity). Interacts with NCS1/FREQ at the Golgi complex. Interacts with RAB11FIP3 and RAB11FIP4 (By similarity). Belongs to the small GTPase superfamily. Arf family.