OPN5

Opsin-5 is a is_associated_with::protein that in humans is encoded by the OPN5 is_associated_with::gene. It is a is_associated_with::photoreceptor protein sensitive to ultraviolet (UV) light. The OPN5 gene was discovered in mouse and human genomes and its mRNA expression was also discovered in neural tissues. Opsin-5 activates a UV-sensitive, heterotrimeric is_associated_with::G protein Gi-mediated pathway in mammalian tissues.

Function
is_associated_with::Opsins are members of the G protein-coupled receptor superfamily. OPN5 is expressed in the eye, brain, testes, and spinal cord. This gene belongs to the seven-exon subfamily of mammalian opsin genes that includes is_associated_with::peropsin (RRH) and is_associated_with::retinal G protein coupled receptor (RGR). Like these other seven-exon opsin genes, this gene encodes a protein with photoisomerase activity. Alternative splicing results in multiple transcript variants encoding different is_associated_with::isoforms.

Photochemistry
Upon reconstitution with is_associated_with::11-cis-retinal, mouse Opn5 shows an absorption maximum of 380 nm. This causes the conversion of OPN5 into a blue-absorbing photoproduct (470 nm), which is stable in the dark. Orange illumination then causes its re-conversion back into the UV- absorbing state.