May play a role in an as yet undefined retina-specific signal transduction. Could bind to photoactivated-phosphorylated red/green opsins. Homodimer; disulfide-linked in response to retinal illumination (By similarity). Interacts with CXCR4; the interaction is dependent on the C-terminal phosphorylation of CXCR4 and modulates the calcium ion mobilization activity of CXCR4 (PubMed:20048153). Inner and outer segments, and the inner plexiform regions of the retina. The disease may be caused by variants affecting the gene represented in this entry. Belongs to the arrestin family.