Probable component of a guanine nucleotide exchange factor (GEF) that may be required for efficient fusion of endosome-derived vesicles with the Golgi (By similarity). Plays a role in regulating Rab6-dependent CadN transport in photoreceptor cells which is required for the formation of normal synaptic connections between axons from the inner photoreceptor cells in the eye and postsynaptic cells in the brain medulla layer M6, and for the generation of normal postsynaptic responses. Component of a guanine nucleotide exchange factor (GEF) complex (By similarity). Interacts with Rab6. Colocalizes with Rab6 at the Golgi apparatus. In third-instar larvae, detected in most cells of the optic lobes, showing an enrichment in the lamina and the medulla neuropil. At pupal stage, expressed in photoreceptor cells, as well as in the postsynaptic cells that form the lamina plexus and medulla. Also expressed in salivary glands and pupal eye imaginal disks. In mutant flies, axons from R7 photoreceptor cells in the eye fail to reach their normal target in brain medulla layer M6, but instead target layer M3. This leads to defects in synaptic signal transmission. Differentiation of photoreceptors is not affected. Belongs to the RIC1 family.