Light stimulates opsin receptors

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R-HSA-419841
Type
Reaction [binding]
Species
Homo sapiens
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Rhodopsin (encoded by the human gene OPN2) (Nathans J and Hogness DS, 1984) is expressed in rod photoreceptor cells used in night vision. In humans, three opsins are expressed in cone cells used for colour vision. The opsin 1 gene OPN1MW encodes a protein called green cone photopigment or medium-wave-sensitive opsin (Nathans J et al, 1986). Defects in OPN1MW are the cause of partial colorblindness called deuteranopia (Winderickx J et al, 1992).
The opsin 1 gene OPN1LW encodes a protein called red cone photopigment or long-wavelength sensitive opsin (Nathans J et al, 1986). Defects in this gene are the cause of partial colorblindness (protanopia) (Winderickx J et al, 1992). The opsin 1 gene OPN1SW encodes for blue-sensitive opsins (BOP) (Nathans J et al, 1986). A deficiency in function or numbers (or both) of BOP results in a selective deficiency of blue spectral sensitivity. This is called Tritanopia, an autosomal dominant genetic disorder of human vision (Weitz CJ et al, 1992).
The human gene OPN3 encodes opsin 3 (encephalopsin, panopsin) (Blackshaw S and Snyder SH, 1999). It is strongly expressed in brain and testis with features of a classical photoreceptive opsin. The human gene OPN5 encodes opsin 5, which is expressed in the eye, brain, testes, and spinal cord (Tarttelin EE et al, 2003).
The visual pigment-like receptor peropsin (RRH) is found only in the eye, where it is localized to the retinal pigment epithelium (RPE) (Sun H et al, 1997). In the RPE, it is localized to the microvilli that surround the photoreceptor outer segments. It may play a role in RPE physiology, either by detecting light directly or by monitoring the concentration of retinoids or other photoreceptor-derived compounds.
The putative RPE-retinal G protein coupled receptor (RGR) (Shen D et al, 1994) covalently binds both all-trans- and 11-cis-retinal after reduction by sodium borohydride. The 32-kDa receptor binds all-trans-retinal preferentially, rather than the 11-cis isomer. Defects in RGR are a cause of autosomal recessive retinitis pigmentosa (ARRP). RP leads to degeneration of retinal photoreceptor cells (Morimura H et al, 1999).
Transducin (also called Gt) is a heterotrimeric G protein that is naturally expressed in vertebrate retina rods and cones and couple with these opsins to mediate the stimulation of cGMP hydrolysis.

Literature References
PubMed ID Title Journal Year
10234000 Encephalopsin: a novel mammalian extraretinal opsin discretely localized in the brain

Blackshaw, S, Snyder, SH

J Neurosci 1999
10581022 Mutations in RGR, encoding a light-sensitive opsin homologue, in patients with retinitis pigmentosa

Morimura, H, Saindelle-Ribeaudeau, F, Berson, EL, Dryja, TP

Nat Genet 1999
9275222 Peropsin, a novel visual pigment-like protein located in the apical microvilli of the retinal pigment epithelium

Sun, H, Gilbert, DJ, Copeland, NG, Jenkins, NA, Nathans, J

Proc Natl Acad Sci U S A 1997
1557123 Polymorphism in red photopigment underlies variation in colour matching

Winderickx, J, Lindsey, DT, Sanocki, E, Teller, DY, Motulsky, AG, Deeb, SS

Nature 1992
1302020 Defective colour vision associated with a missense mutation in the human green visual pigment gene

Winderickx, J, Sanocki, E, Lindsey, DT, Teller, DY, Motulsky, AG, Deeb, SS

Nat Genet 1992
14623103 Neuropsin (Opn5): a novel opsin identified in mammalian neural tissue

Tarttelin, EE, Bellingham, J, Hankins, MW, Foster, RG, Lucas, RJ

FEBS Lett 2003
1531728 Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin

Weitz, CJ, Miyake, Y, Shinzato, K, Montag, E, Zrenner, E, Went, LN, Nathans, J

Am J Hum Genet 1992
6589631 Isolation and nucleotide sequence of the gene encoding human rhodopsin.

Nathans, J, Hogness, DS

Proc Natl Acad Sci U S A 1984
2937147 Molecular genetics of human color vision: the genes encoding blue, green, and red pigments

Nathans, J, Thomas, D, Hogness, DS

Science 1986
7947717 A human opsin-related gene that encodes a retinaldehyde-binding protein

Shen, D, Jiang, M, Hao, W, Tao, L, Salazar, M, Fong, HK

Biochemistry 1994
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