Opsin-3 is a protein that, in humans, is encoded by the OPN3 gene. Alternative splicing of this gene results in multiple transcript variants encoding different protein isoforms.

Opsins are members of the guanine nucleotide-binding protein (G protein)-coupled receptor superfamily. In addition to the visual opsins, mammals possess several photoreceptive non-visual opsins that are expressed in extraocular tissues. This gene, opsin 3, is strongly expressed in brain and testis and weakly expressed in liver, placenta, heart, lung, skeletal muscle, kidney, and pancreas. The gene may also be expressed in the retina. The protein has the canonical features of a photoreceptive opsin protein. [provided by RefSeq, Jul 2008].
Function: May play a role in encephalic photoreception.