RRH

Last updated
RRH
Identifiers
Aliases RRH , retinal pigment epithelium-derived rhodopsin homolog
External IDs OMIM: 605224 MGI: 1097709 HomoloGene: 55977 GeneCards: RRH
Orthologs
SpeciesHumanMouse
Entrez

10692

20132

Ensembl

ENSG00000180245

ENSMUSG00000028012

UniProt

O14718

O35214

RefSeq (mRNA)

NM_006583

NM_009102

RefSeq (protein)

NP_006574

NP_033128

Location (UCSC) Chr 4: 109.83 – 109.85 Mb Chr 3: 129.6 – 129.62 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Peropsin, a visual pigment-like receptor, is a protein that in humans is encoded by the RRH gene. [5] [6] It belongs like other animal opsins to the G protein-coupled receptors. [6] Even so, the first peropsins were already discovered in mice and humans in 1997, [5] not much is known about them. [7]

Contents

Photochemistry

Like most opsins, peropsins have in its seventh transmembrane domain a lysine corresponding to amino acid position 296 in cattle rhodopsin, [5] [7] which is important for retinal binding and light sensing. [8]

In amphioxus, a cephalochordate, a peropsin binds in the dark-state all-trans-retinal instead of 11-cis-retinal, [9] as it is in cattle rhodopsin. [10] [11] [12] [13] [14] Therefore, peropsins have been suggested to be photoisomerases. [9]

Tissue localization

In mice, a peropsin is localized to the apical microvilli of the retinal pigment epithelium (RPE). [5] There, it regulates storage or the movement of vitamin A from the retina to the RPE. [15] A peropsin is also expressed in keratinocytes of the human skin. In keratinocyte cell culture, it reacts to UV light if retinal is supplied. [16] In chicken, a peropsin is expressed with an RGR-opsin in the pineal gland and the retina. [17]

Gene localization and structure

The human peropsin gene lies on chromosome 4 band 4q25 and has six introns [6] [18] like RGR-opsins. However only two of these introns are inserted at the same place, which still indicates that peropsins and RGR-opsins are more closely related to each other than to the ciliary and rhabdomeric opsins. [18] This shared gene structure is also reflected in opsin phylogenies, where peropsins and RGR-opsins are in the same group: The chromopsins. [18] [7] [19] [20]

Phylogeny

The peropsins are restricted to the craniates and the cephalochordates. [7] The craniates are the taxon that contains mammals and with them humans. The peropsins are one of the seven subgroups of the chromopsins. The other groups are the RGR-opsins, the retinochromes, the nemopsins, the astropsins, the varropsins, and the gluopsins. [7] The chromopsins are one of three subgroups of the tetraopsins (also known as RGR/Go or Group 4 opsins). The other groups are the neuropsins and the Go-opsins. The tetraopsins are one of the five major groups of the animal opsins, also known as type 2 opsins). The other groups are the ciliary opsins (c-opsins, cilopsins), the rhabdomeric opsins (r-opsins, rhabopsins), the xenopsins, and the nessopsins. Four of these subclades occur in Bilateria (all but the nessopsins). [7] [19] However, the bilaterian clades constitute a paraphyletic taxon without the opsins from the cnidarians. [7] [19] [20] [21]

In the phylogeny above, Each clade contains sequences from opsins and other G protein-coupled receptors. The number of sequences and two pie charts are shown next to the clade. The first pie chart shows the percentage of a certain amino acid at the position in the sequences corresponding to position 296 in cattle rhodopsin. The amino acids are color-coded. The colors are red for lysine (K), purple for glutamic acid (E), orange for arginine (R), dark and mid-gray for other amino acids, and light gray for sequences that have no data at that position. The second pie chart gives the taxon composition for each clade, green stands for craniates, dark green for cephalochordates, mid green for echinoderms, brown for nematodes, pale pink for annelids, dark blue for arthropods, light blue for mollusks, and purple for cnidarians. The branches to the clades have pie charts, which give support values for the branches. The values are from right to left SH-aLRT/aBayes/UFBoot. The branches are considered supported when SH-aLRT ≥ 80%, aBayes ≥ 0.95, and UFBoot ≥ 95%. If a support value is above its threshold the pie chart is black otherwise gray. [7]

Clinical significance

Since RGR-opsin may be associated with retinitis pigmentosa, [22] which is like peropsin also expressed in the retinal pigment epithelium, peropsin was screened for a link with retinitis pigmentosa. [23] However, no link could be established. [23] [24]

Related Research Articles

<span class="mw-page-title-main">Retinol</span> Chemical compound

Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. Dietary sources include fish, dairy products, and meat. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xerophthalmia. It is taken by mouth or by injection into a muscle. As an ingredient in skin-care products, it is used to reduce wrinkles and other effects of skin aging.

<span class="mw-page-title-main">Rhodopsin</span> Light-sensitive receptor protein

Rhodopsin, also known as visual purple, is a protein encoded by the RHO gene and a G-protein-coupled receptor (GPCR). It is the opsin of the rod cells in the retina and a light-sensitive receptor protein that triggers visual phototransduction in rods. Rhodopsin mediates dim light vision and thus is extremely sensitive to light. When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 30 minutes, after which the rods are more sensitive. Defects in the rhodopsin gene cause eye diseases such as retinitis pigmentosa and congenital stationary night blindness.

<span class="mw-page-title-main">Retinitis pigmentosa</span> Gradual retinal degeneration leading to progressive sight loss

Retinitis pigmentosa (RP) is a genetic disorder of the eyes that causes loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision. As peripheral vision worsens, people may experience "tunnel vision". Complete blindness is uncommon. Onset of symptoms is generally gradual and often begins in childhood.

<span class="mw-page-title-main">Rod cell</span> Photoreceptor cells that can function in lower light better than cone cells

Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in peripheral vision. On average, there are approximately 92 million rod cells in the human retina. Rod cells are more sensitive than cone cells and are almost entirely responsible for night vision. However, rods have little role in color vision, which is the main reason why colors are much less apparent in dim light.

In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher illumination levels. Night vision is of lower quality than day vision because it is limited in resolution and colors cannot be discerned; only shades of gray are seen. In order for humans to transition from day to night vision they must undergo a dark adaptation period of up to two hours in which each eye adjusts from a high to a low luminescence "setting", increasing sensitivity hugely, by many orders of magnitude. This adaptation period is different between rod and cone cells and results from the regeneration of photopigments to increase retinal sensitivity. Light adaptation, in contrast, works very quickly, within seconds.

<span class="mw-page-title-main">Retinal</span> Chemical compound

Retinal is a polyene chromophore. Retinal, bound to proteins called opsins, is the chemical basis of visual phototransduction, the light-detection stage of visual perception (vision).

<span class="mw-page-title-main">Opsin</span> Class of light-sensitive proteins

Animal opsins are G-protein-coupled receptors and a group of proteins made light-sensitive via a chromophore, typically retinal. When bound to retinal, opsins become retinylidene proteins, but are usually still called opsins regardless. Most prominently, they are found in photoreceptor cells of the retina. Five classical groups of opsins are involved in vision, mediating the conversion of a photon of light into an electrochemical signal, the first step in the visual transduction cascade. Another opsin found in the mammalian retina, melanopsin, is involved in circadian rhythms and pupillary reflex but not in vision. Humans have in total nine opsins. Beside vision and light perception, opsins may also sense temperature, sound, or chemicals.

<span class="mw-page-title-main">Retinal pigment epithelium</span>

The pigmented layer of retina or retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells.

Retinylidene proteins, or rhodopsins in a broad sense, are proteins that use retinal as a chromophore for light reception. They are the molecular basis for a variety of light-sensing systems from phototaxis in flagellates to eyesight in animals. Retinylidene proteins include all forms of opsin and rhodopsin. While rhodopsin in the narrow sense refers to a dim-light visual pigment found in vertebrates, usually on rod cells, rhodopsin in the broad sense refers to any molecule consisting of an opsin and a retinal chromophore in the ground state. When activated by light, the chromophore is isomerized, at which point the molecule as a whole is no longer rhodopsin, but a related molecule such as metarhodopsin. However, it remains a retinylidene protein. The chromophore then separates from the opsin, at which point the bare opsin is a retinylidene protein. Thus, the molecule remains a retinylidene protein throughout the phototransduction cycle.

The visual cycle is a process in the retina that replenishes the molecule retinal for its use in vision. Retinal is the chromophore of most visual opsins, meaning it captures the photons to begin the phototransduction cascade. When the photon is absorbed, the 11-cis retinal photoisomerizes into all-trans retinal as it is ejected from the opsin protein. Each molecule of retinal must travel from the photoreceptor cell to the RPE and back in order to be refreshed and combined with another opsin. This closed enzymatic pathway of 11-cis retinal is sometimes called Wald's visual cycle after George Wald (1906–1997), who received the Nobel Prize in 1967 for his work towards its discovery.

<span class="mw-page-title-main">Photoreceptor cell-specific nuclear receptor</span> Protein-coding gene in the species Homo sapiens

The photoreceptor cell-specific nuclear receptor (PNR), also known as NR2E3, is a protein that in humans is encoded by the NR2E3 gene. PNR is a member of the nuclear receptor super family of intracellular transcription factors.

<span class="mw-page-title-main">OPN5</span> Protein-coding gene in the species Homo sapiens

Opsin-5, also known as G-protein coupled receptor 136 or neuropsin is a protein that in humans is encoded by the OPN5 gene. Opsin-5 is a member of the opsin subfamily of the G protein-coupled receptors. It is a photoreceptor protein sensitive to ultraviolet (UV) light. The OPN5 gene was discovered in mouse and human genomes and its mRNA expression was also found in neural tissues. Neuropsin is bistable at 0 °C and activates a UV-sensitive, heterotrimeric G protein Gi-mediated pathway in mammalian and avian tissues.

<span class="mw-page-title-main">Retinal G protein coupled receptor</span> Protein-coding gene in the species Homo sapiens

RPE-retinal G protein-coupled receptor also known as RGR-opsin is a protein that in humans is encoded by the RGR gene. RGR-opsin is a member of the rhodopsin-like receptor subfamily of GPCR. Like other opsins which bind retinaldehyde, it contains a conserved lysine residue in the seventh transmembrane domain. RGR-opsin comes in different isoforms produced by alternative splicing.

<span class="mw-page-title-main">RPE65</span> Protein-coding gene in humans

Retinal pigment epithelium-specific 65 kDa protein, also known as retinoid isomerohydrolase, is an enzyme of the vertebrate visual cycle that is encoded in humans by the RPE65 gene. RPE65 is expressed in the retinal pigment epithelium and is responsible for the conversion of all-trans-retinyl esters to 11-cis-retinol during phototransduction. 11-cis-retinol is then used in visual pigment regeneration in photoreceptor cells. RPE65 belongs to the carotenoid oxygenase family of enzymes.

<span class="mw-page-title-main">Retinaldehyde-binding protein 1</span> Protein-coding gene in the species Homo sapiens

Retinaldehyde-binding protein 1 (RLBP1) also known as cellular retinaldehyde-binding protein (CRALBP) is a 36-kD water-soluble protein that in humans is encoded by the RLBP1 gene.

<span class="mw-page-title-main">SAG (gene)</span>

S-arrestin is a protein that in humans is encoded by the SAG gene.

<span class="mw-page-title-main">Retinal degeneration (rhodopsin mutation)</span> Retinopathy

Retinal degeneration is a retinopathy which consists in the deterioration of the retina caused by the progressive death of its cells. There are several reasons for retinal degeneration, including artery or vein occlusion, diabetic retinopathy, R.L.F./R.O.P., or disease. These may present in many different ways such as impaired vision, night blindness, retinal detachment, light sensitivity, tunnel vision, and loss of peripheral vision to total loss of vision. Of the retinal degenerative diseases retinitis pigmentosa (RP) is a very important example.

Retinal gene therapy holds a promise in treating different forms of non-inherited and inherited blindness.

Spizellomyces punctatus is a chytrid fungus living in soil. It is a saprotrophic fungus that colonizes decaying plant material. Being an early diverging fungus, S. punctatus retains ancestral cellular features that are also found in animals and amoebae. Its pathogenic relatives, Batrachochytrium dendrobatidis and B. salamandrivorans, infect amphibians and cause global biodiversity loss. The pure culture of S. punctatus was first obtained by Koch.

<span class="mw-page-title-main">Vertebrate visual opsin</span>

Vertebrate visual opsins are a subclass of ciliary opsins and mediate vision in vertebrates. They include the opsins in human rod and cone cells. They are often abbreviated to opsin, as they were the first opsins discovered and are still the most widely studied opsins.

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000180245 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000028012 - Ensembl, May 2017
  3. ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. 1 2 3 4 Sun H, Gilbert DJ, Copeland NG, Jenkins NA, Nathans J (September 1997). "Peropsin, a novel visual pigment-like protein located in the apical microvilli of the retinal pigment epithelium". Proceedings of the National Academy of Sciences of the United States of America. 94 (18): 9893–9898. Bibcode:1997PNAS...94.9893S. doi: 10.1073/pnas.94.18.9893 . PMC   23288 . PMID   9275222.
  6. 1 2 3 "Entrez Gene: RRH retinal pigment epithelium-derived rhodopsin homolog".
  7. 1 2 3 4 5 6 7 8 Gühmann M, Porter ML, Bok MJ (August 2022). "The Gluopsins: Opsins without the Retinal Binding Lysine". Cells. 11 (15): 2441. doi: 10.3390/cells11152441 . PMC   9368030 . PMID   35954284. CC-BY icon.svg Material was copied and adapted from this source, which is available under a Creative Commons Attribution 4.0 International License.
  8. ↑ Leung NY, Thakur DP, Gurav AS, Kim SH, Di Pizio A, Niv MY, et al. (April 2020). "Functions of Opsins in Drosophila Taste". Current Biology. 30 (8): 1367–1379.e6. Bibcode:2020CBio...30E1367L. doi:10.1016/j.cub.2020.01.068. PMC   7252503 . PMID   32243853.
  9. 1 2 Koyanagi M, Terakita A, Kubokawa K, Shichida Y (November 2002). "Amphioxus homologs of Go-coupled rhodopsin and peropsin having 11-cis- and all-trans-retinals as their chromophores". FEBS Letters. 531 (3): 525–528. doi: 10.1016/s0014-5793(02)03616-5 . PMID   12435605. S2CID   11669142.
  10. ↑ Wald G (July 1934). "Carotenoids and the Vitamin A Cycle in Vision". Nature. 134 (3376): 65. Bibcode:1934Natur.134...65W. doi: 10.1038/134065a0 . S2CID   4022911.
  11. ↑ Wald G, Brown PK, Hubbard R, Oroshnik W (July 1955). "Hindered Cis Isomers of Vitamin A and Retinene: The Structure of the Neo-B Isomer". Proceedings of the National Academy of Sciences of the United States of America. 41 (7): 438–451. Bibcode:1955PNAS...41..438W. doi: 10.1073/pnas.41.7.438 . PMC   528115 . PMID   16589696.
  12. ↑ Brown PK, Wald G (October 1956). "The neo-b isomer of vitamin A and retinene". The Journal of Biological Chemistry. 222 (2): 865–877. doi: 10.1016/S0021-9258(20)89944-X . PMID   13367054.
  13. ↑ Oroshnik W (June 1956). "The Synthesis and Configuration of Neo-B Vitamin A and Neoretinine b". Journal of the American Chemical Society. 78 (11): 2651–2652. doi:10.1021/ja01592a095.
  14. ↑ Oroshnik W, Brown PK, Hubbard R, Wald G (September 1956). "Hindered Cis Isomers of Vitamin A and Retinene: The Structure of the Neo-B Isomer". Proceedings of the National Academy of Sciences of the United States of America. 42 (9): 578–580. Bibcode:1956PNAS...42..578O. doi: 10.1073/pnas.42.9.578 . PMC   534254 . PMID   16589909.
  15. ↑ Cook JD, Ng SY, Lloyd M, Eddington S, Sun H, Nathans J, et al. (December 2017). "Peropsin modulates transit of vitamin A from retina to retinal pigment epithelium". The Journal of Biological Chemistry. 292 (52): 21407–21416. doi: 10.1074/jbc.M117.812701 . PMC   5766940 . PMID   29109151.
  16. ↑ Toh PP, Bigliardi-Qi M, Yap AM, Sriram G, Stelmashenko O, Bigliardi P (December 2016). "Expression of peropsin in human skin is related to phototransduction of violet light in keratinocytes". Experimental Dermatology. 25 (12): 1002–1005. doi: 10.1111/exd.13226 . PMID   27676658. S2CID   1373924.
  17. ↑ Bailey MJ, Cassone VM (March 2004). "Opsin photoisomerases in the chick retina and pineal gland: characterization, localization, and circadian regulation". Investigative Ophthalmology & Visual Science. 45 (3): 769–775. doi:10.1167/iovs.03-1125. PMID   14985289.
  18. 1 2 3 Bellingham J, Wells DJ, Foster RG (January 2003). "In silico characterisation and chromosomal localisation of human RRH (peropsin)--implications for opsin evolution". BMC Genomics. 4 (1): 3. doi: 10.1186/1471-2164-4-3 . PMC   149353 . PMID   12542842.
  19. 1 2 3 Ramirez MD, Pairett AN, Pankey MS, Serb JM, Speiser DI, Swafford AJ, et al. (26 October 2016). "The last common ancestor of most bilaterian animals possessed at least 9 opsins". Genome Biology and Evolution: evw248. doi: 10.1093/gbe/evw248 . PMC   5521729 . PMID   27797948.
  20. 1 2 Porter ML, Blasic JR, Bok MJ, Cameron EG, Pringle T, Cronin TW, et al. (January 2012). "Shedding new light on opsin evolution". Proceedings. Biological Sciences. 279 (1726): 3–14. doi:10.1098/rspb.2011.1819. PMC   3223661 . PMID   22012981.
  21. ↑ Liegertová M, Pergner J, Kozmiková I, Fabian P, Pombinho AR, Strnad H, et al. (July 2015). "Cubozoan genome illuminates functional diversification of opsins and photoreceptor evolution". Scientific Reports. 5: 11885. Bibcode:2015NatSR...511885L. doi:10.1038/srep11885. PMC   5155618 . PMID   26154478.
  22. ↑ Morimura H, Saindelle-Ribeaudeau F, Berson EL, Dryja TP (December 1999). "Mutations in RGR, encoding a light-sensitive opsin homologue, in patients with retinitis pigmentosa". Nature Genetics. 23 (4): 393–394. doi:10.1038/70496. PMID   10581022. S2CID   35176366.
  23. 1 2 Ksantini M, Sénéchal A, Humbert G, Arnaud B, Hamel CP (March 2007). "RRH, encoding the RPE-expressed opsin-like peropsin, is not mutated in retinitis pigmentosa and allied diseases" (PDF). Ophthalmic Genetics. 28 (1): 31–37. doi:10.1080/13816810701202052. PMID   17454745. S2CID   225451.
  24. ↑ Rivolta C, Berson EL, Dryja TP (December 2006). "Mutation screening of the peropsin gene, a retinal pigment epithelium specific rhodopsin homolog, in patients with retinitis pigmentosa and allied diseases". Molecular Vision. 12: 1511–1515. PMID   17167409.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.