Opsin 5 (OPN5)

Opsins are members of the guanine nucleotide-binding protein (G protein)-coupled receptor superfamily. This opsin gene is expressed in the eye, brain, testes, and spinal cord. OPN5 belongs to the seven-exon subfamily of mammalian opsin genes that includes peropsin (RRH) and retinal G protein coupled receptor (RGR). Like these other seven-exon opsin genes, this gene may encode a protein with photoisomerase activity. Alternative splicing results in multiple transcript variants encoding different isoforms.The deduced 472-amino acid protein contains the characteristic 7 transmembrane (TM) domains, a DRY motif in the intracellular side of TM3, and a rhodopsin GPR-like NPxxY motif in TM7. GPR136 shares 96% amino acid identity with mouse Gpr136. EST database analysis indicated that GPR136 is expressed in testis.