Plays a role in the synapse formation and synaptic transmission between cone photoreceptor cells and retinal bipolar cells (By similarity). Required for normal transmission of a light-evoked stimulus from the cone photoreceptor cells to the ON-bipolar cells and ON-ganglion cells in the inner retina (PubMed:28334377). Required in retinal ON-bipolar cells for normal localization of the cation channel TRPM1 at dendrite tips (By similarity). Seems to play a specific role in synaptic contacts made by ON-bipolar cells with cone photoreceptor pedicles (By similarity). May also have a role in cone synapse formation (By similarity). Might facilitate FGFR1 exit from the endoplasmic reticulum to the Golgi (PubMed:22673519). Could be a regulator of the FGFRs (PubMed:22673519). Punctate expression at dendrite tips. Detected in the outer plexiform layer (OPL) of the retina where it localizes to ON-bipolar cells (at protein level). Glycosylated. The disease is caused by variants affecting the gene represented in this entry. Truncated N-terminus.