Required for the localization of ZFYVE1 to lipid droplets and for its function in mediating the formation of endoplasmic reticulum-lipid droplets (ER-LD) contacts (By similarity). Plays a role in apical endocytosis/recycling (By similarity). Plays a key role in eye and brain development and neurodegeneration (By similarity). Interacts (in GTP-bound form) with ZFYVE1 (By similarity). Interacts with ZW10 and this interaction is enhanced in the presence of ZFYVE1 (By similarity). Interacts with BSCL2 (By similarity). Belongs to the small GTPase superfamily. Rab family.