Opsin - Knowledge

439: 426: 410: 1598:. They preferentially bind all-trans-retinal in the dark instead of 11-cis-retinal. RGR-opsins were thought to be photoisomerases but instead, they regulate retinoid traffic and production. In particular, they speed up light-independently the production of 11-cis-retinol (a precursor of 11-cis-retinal) from all-trans-retinyl-esters. However, the all-trans-retinyl-esters are made available light-dependently by RGR-opsins. Whether RGR-opsins regulate this via a G-protein or another signaling mechanism is unknown. The cattle RGR-opsin absorbs maximally at different wavelengths depending on the pH-value. At high pH it absorbs maximally blue (469 nm) light and at low pH it absorbs maximally UV (370 nm) light. 633: 438: 39: 391:. These opsins still have Lys296 like other opsins. However, if this lysine is replaced by an arginine in Rh1, then Rh1 loses light sensitivity but still responds to aristolochic acid. Thus, Lys296 is not needed for Rh1 to function as chemoreceptor. Also the Drosophila rhabopsins Rh1 and Rh6 are involved in mechanoreception, again for mechanoreception Lys296 is not needed, but needed for proper function in the photoreceptor cells. 27: 3050: 425: 1731:. As a result, several studies have found evidence of a possible phylogenetic relationship between the two. However, this does not necessarily mean that the last common ancestor of microbial and animal opsins was itself light sensitive: All animal opsins arose (by gene duplication and divergence) late in the history of the large 705:, residues important for the proper functioning of the opsin. They are not mutually exclusive, but, for practical reasons, it is easier to investigate spectral tuning sites that do not affect opsin functionality. For a comprehensive review of spectral tuning sites see Yokoyama and Deeb. The impact of spectral tuning sites on 516:. 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. 238:. Actually, insertions and deletions in the α-helices are very rare and should preferentially occur in the loops. Therefore, different G-protein-coupled receptors have different length and homologous residues may be in different positions. To make such positions comparable between different receptors, Ballesteros and 1543:

Neuropsins are sensitive to UVA, typically at 380 nm. They are found in the brain, testes, skin, and retina of humans and rodents, as well as in the brain and retina of birds. In birds and rodents they mediate ultraviolet vision. They couple to Gi-proteins. In humans, Neuropsin is encoded by the

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couple to Gs-proteins raising the intracellular cAMP level. Coral opsins can couple to Gq-proteins and Gc-proteins. Gc-proteins are a subtype of G-proteins specific to cnidarians. The cnidarian opsins belong to two groups the xenopsins and the nessopsins. The xenopsins contain also bilaterian opsins,

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introduced a common numbering scheme for G-protein-coupled receptors. The number before the period is the number of the transmembrane domain. The number after the period is set arbitrarily to 50 for the most conserved residue in that transmembrane domain among GPCRs known in 1995. For instance in the

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Rhabdomeric opsins (rhabopsins, r-opsins) are also known as Gq-opsins, because they couple to a Gq-protein. Rhabopsins are used by molluscs and arthropods. Arthropods appear to attain colour vision in a similar fashion to the vertebrates, by using three (or more) distinct groups of opsins, distinct

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The retinal molecule inside an opsin protein absorbs a photon of light. Absorption of the photon causes retinal to change from its 11-cis-retinal isomer into its all-trans-retinal isomer. This change in shape of retinal pushes against the outer opsin protein to begin a signal cascade, which may

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Ciliary opsins (cilopsins, c-opsins) are expressed in ciliary photoreceptor cells, and include the vertebrate visual opsins and encephalopsins. They convert light signals to nerve impulses via cyclic nucleotide gated ion channels, which work by increasing the charge differential across the cell

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Beside these functions, an opsin without Lys296, such as a gluopsin, could still be light sensitive, since in cattle rhodopsin, the retinal binding lysine can be shifted from position 296 to other positions, even into other transmembrane domains, without changing light sensitivity.

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Borroto-Escuela DO, Romero-Fernandez W, García-Negredo G, Correia PA, Garriga P, Fuxe K, Ciruela F (2011). "Dissecting the conserved NPxxY motif of the M3 muscarinic acetylcholine receptor: critical role of Asp-7.49 for receptor signaling and multiprotein complex formation".

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Consensus sequences of the different chromopsins: The first column contains a number for each chromopsin group for easy reference. The second column shows the names for each group. The third contains the number of sequences in each group. And the fourth column contains the

670:. Glu113 serves as the counterion, stabilizing the protonation of the Schiff linkage between Lys296 and the ligand retinal. The Glu134-Arg135-Tyr136 is another highly conserved motif, involved in the propagation of the transduction signal once a photon has been absorbed. 1111:

opsins are attached to light-gathering organelles called rhabdomeres. This classification cuts across phylogenetic categories (clades) so that both the terms "ciliary" and "rhabdomeric" can be ambiguous. Here, "C-opsins (ciliary)" refers to a clade found exclusively in

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Halford S, Freedman MS, Bellingham J, Inglis SL, Poopalasundaram S, Soni BG, et al. (March 2001). "Characterization of a novel human opsin gene with wide tissue expression and identification of embedded and flanking genes on chromosome 1q43".

1739:, which itself arose after the divergence of plants, fungi, choanflagellates and sponges from the earliest animals. The retinal chromophore is found solely in the opsin branch of this large gene family, meaning its occurrence elsewhere represents 294:, this lysine is the 296th amino acid and thus according to both numbering schemes Lys296. It is well conserved among opsins, so well conserved that sequences without it were not even considered opsins and thus excluded from large scale 1899:

to switch on or off neuronal activity. Microbal opsins are preferred if the neuronal activity should be modulated at higher frequency, because they respond faster than animal opsins. This is because microbal opsins are ion channels or

1788:. In Eukaryota, microbial opsins are found mainly in unicellular organisms such as green algae, and in fungi. In most complex multicellular eukaryotes, microbial opsins have been replaced with other light-sensitive molecules such as 1712:

Microbial and animal opsins are also called type 1 and type 2 opsins respectively. Both types are called opsins, because at one time it was thought that they were related: Both are seven-transmembrane receptors and bind covalently

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Most tetraopsins have also the retinal binding lysine except some of the chromopsins, which are highlighted by the frame and expanded in the next image. The outgroup contains other G protein-coupled receptors including the other

1511:, and color correction in high-brightness situations. Phylogenetically, it is a member of the rhabdomeric opsins (rhabopsins, r-opsins) and functionally and structurally a rhabopsin, but does not occur in rhabdomeres. 629:). Furthermore, when the motif is mutated to NAxxY (Pro → Ala) in cattle rhodopsin, the mutant has 141% of wild type activity. This evidence shows that a GPCR does not need a standard NPxxY motif for signaling. 1408:

Panopsins are also expressed in the brains of some insects. The panopsins of mosquito and pufferfish absorb maximally at 500 nm and 460 nm, respectively. Both activate in vitro Gi and Go proteins.

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light (480 nm) is left. Thus, the larvae can determine their depth by color. The color unlike brightness stays almost constant independent of time of day or the weather, for instance if it is cloudy.

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Moutsaki P, Whitmore D, Bellingham J, Sakamoto K, David-Gray ZK, Foster RG (April 2003). "Teleost multiple tissue (tmt) opsin: a candidate photopigment regulating the peripheral clocks of zebrafish?".

7373:"Retinal pigment epithelium-retinal G protein receptor-opsin mediates light-dependent translocation of all-trans-retinyl esters for synthesis of visual chromophore in retinal pigment epithelial cells" 3116:

Ballesteros JA, Weinstein H (1995). "Integrated methods for the construction of three-dimensional models and computational probing of structure-function relations in G protein-coupled receptors".

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Unlike cilopsins, rhabopsins are associated with canonical transient receptor potential ion channels; these lead to the electric potential difference across a cell membrane being eradicated (i.e.

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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

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In fact, the sequence identity between animal and mirobial opsins is no greater than could be accounted for by random chance. However, in recent years new methods have been developed specific to

657:(E). The NPxxY motif is highlighted with a gray background. It is conserved in most opsins and G-protein-coupled receptors, however it is derived in the retinochromes, RGR-opsins, and Gluopsins. 484:(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 2079:

Dixon RA, Kobilka BK, Strader DJ, Benovic JL, Dohlman HG, Frielle T, et al. (May 1986). "Cloning of the gene and cDNA for mammalian beta-adrenergic receptor and homology with rhodopsin".

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Philp AR, Garcia-Fernandez JM, Soni BG, Lucas RJ, Bellingham J, Foster RG (June 2000). "Vertebrate ancient (VA) opsin and extraretinal photoreception in the Atlantic salmon (Salmo salar)".

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have VPxxY7.53 for annelids or YPxxY7.53 for mollusks, natively. Both RGR-opsins and retinochromes, belong to the chromopsins. RGR-opsins and retinochromes also bind unlike most opsins all-

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Mazna P, Grycova L, Balik A, Zemkova H, Friedlova E, Obsilova V, et al. (November 2008). "The role of proline residues in the structure and function of human MT2 melatonin receptor".

5028: 1228:(ray-finned fish) apparently arose as a result of gene duplication from Rh1 (rhodopsin). These opsins appear to serve functions similar to those of pinopsin found in birds and reptiles. 625:

and has an NAxxY motif natively. If this motif is mutated to NPxxY (Ala → Pro), the receptor cannot be activated, but can be rescued partially if the motif is mutated to NVxxY (Ala →

551:). Such a mutation to APxxY (Asn → Ala) reduces the G-protein activation of cattle rhodopsin to 45% compared to wild type. Also in cattle rhodopsin, if the motif is mutated to NPxxA ( 1456:

while the nessopsins are restricted to the cnidarians. However, earlier studies have found that some cnidarian opsins belong to the cilopsins, rhabopsins, and the tetraopsins of the

1072:. The nessopsins are also known as anthozoan opsins II or simply as the cnidarian opsins. The tetraopsins are also known as RGR/Go or Group 4 opsins and contain three subgroups: the 1803:

Microbial opsins are often known by the rhodopsin form of the molecule, i.e., rhodopsin (in the broad sense) = opsin + chromophore. Among the many kinds of microbial opsins are the

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fish and therefore they are called Teleost Multiple Tissue (TMT) opsins. TMT-opsins form three groups which are most closely related to a fourth group the panopsins, which thus are

1326:= 522 nm), and despite it is a c-opsin, like the vertebrate visual opsins, it does not induce hyperpolarization via a Gt-protein, but induces depolarization via a Go-protein. 528:

is well-conserved among opsins and G-protein-coupled receptors. This motif is important for G-protein binding and receptor activation. For instance, if it is mutated to DPxxY (

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Su CY, Luo DG, Terakita A, Shichida Y, Liao HW, Kazmi MA, et al. (March 2006). "Parietal-eye phototransduction components and their potential evolutionary implications".

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Dixon RA, Sigal IS, Rands E, Register RB, Candelore MR, Blake AD, Strader CD (March 1987). "Ligand binding to the beta-adrenergic receptor involves its rhodopsin-like core".

4029:"Mutation of Asn-391 within the conserved NPXXY motif of the cholecystokinin B receptor abolishes Gq protein activation without affecting its association with the receptor" 697:, it is possible to selectively mutate these residues and investigate the resulting changes in light absorption properties of the opsin. It is important to differentiate 452:(E). The astropsins, the nemopsins and the gluopsins are highlighted by the frames. The outgroup contains other G protein-coupled receptors including the other opsins. 11121: 3980:"Functional role of proline and tryptophan residues highly conserved among G protein-coupled receptors studied by mutational analysis of the m3 muscarinic receptor" 1262:

Vertebrate Ancient (VA) opsin has three isoforms VA short (VAS), VA medium (VAM), and VA long (VAL). It is expressed in the inner retina, within the horizontal and

4374:"Two Opsin 3-Related Proteins in the Chicken Retina and Brain: A TMT-Type Opsin 3 Is a Blue-Light Sensor in Retinal Horizontal Cells, Hypothalamus, and Cerebellum" 1747:. Microbial rhodopsins are, by sequence, very different from any of the GPCR families. According to one hypothesis, both microbial and animal opsins belong to the 1041:

contain opsin in their skin as part of the chromophores. The opsin is part of the sensing network detecting the colour and shape of the cuttlefish's surroundings.

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Arendt D, Tessmar-Raible K, Snyman H, Dorresteijn AW, Wittbrodt J (October 2004). "Ciliary photoreceptors with a vertebrate-type opsin in an invertebrate brain".

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Nagata T, Koyanagi M, Tsukamoto H, Terakita A (January 2010). "Identification and characterization of a protostome homologue of peropsin from a jumping spider".

1400:: First the red (> 600 nm) and the UV and violet (< 420 nm) wavelengths disappear. The higher the depth the narrower the spectrum so that only 1338:

are found in many tissues (skin, brain, testes, heart, liver, kidney, skeletal muscle, lung, pancreas and retina). They were originally found in the human and

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eventually result in chemical signaling being sent to the brain as visual perception. The retinal is re-loaded by the body so that signaling can happen again.

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Palczewski K, Kumasaka T, Hori T, Behnke CA, Motoshima H, Fox BA, et al. (August 2000). "Crystal structure of rhodopsin: A G protein-coupled receptor".

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Römpler H, Stäubert C, Thor D, Schulz A, Hofreiter M, Schöneberg T (February 2007). "G protein-coupled time travel: evolutionary aspects of GPCR research".

617:-retinal for other opsins. This view is considered established in the opsin literature, even so it has not been shown, conclusively. In fact, the human MT2 645:

given at that position. The x-axis gives the position of the amino acid corresponding to cattle rhodopsin. Positions 292 and 314 are highlighted in gray.

1012: 609:-retinal when illuminated. Therefore, RGR-opsins and retinochromes are thought to neither signal nor activate a phototransduction cascade but to work as 1147:

Vertebrate visual opsins are a subclass of ciliary opsins that express in the vertebrate retina and mediate vision. They are further subdivided into:

10587: 239: 7813:"Independent HHsearch, Needleman--Wunsch-based, and motif analyses reveal the overall hierarchy for most of the G protein-coupled receptor families" 6228:"A ciliary opsin in the brain of a marine annelid zooplankton is ultraviolet-sensitive, and the sensitivity is tuned by a single amino acid residue" 4773:"Human melanopsin forms a pigment maximally sensitive to blue light (λmax ≈ 479 nm) supporting activation of G(q/11) and G(i/o) signalling cascades" 9525: 1811: 9727: 9722: 9717: 9712: 5036: 1528: 1081: 598: 7144:"Analysis of the opsin repertoire in the tardigrade Hypsibius dujardini provides insights into the evolution of opsin genes in panarthropoda" 525: 3548:

Shen WL, Kwon Y, Adegbola AA, Luo J, Chess A, Montell C (March 2011). "Function of rhodopsin in temperature discrimination in Drosophila".

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were determined. The cattle rhodopsin numbering scheme is widespread in the opsin literature. Therefore, it is useful to use both schemes.

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The identification of the crystal structure of squid rhodopsin is likely to further our understanding of its function in this group.

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both in terms of phylogeny and spectral sensitivity. The rhabopsin melanopsin is also expressed in vertebrates, where it regulates

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at the position in the sequences corresponding Lys296 in cattle rhodopsin. The amino acids are color-coded. The colors are red for

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The first parietopsin was found in the photoreceptor cells of the lizard parietal eye. The lizard parietopsin is green-sensitive (

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rhabdomeric opsins (rhabopsins, r-opsins) Rh1, Rh4, and Rh7 function not only as photoreceptors, but also as chemoreceptors for

10918: 9788: 9615: 8102: 1952: 1173:). Vertebrates generally have four (SWS1, SWS2, RH2, LWS) classes of photopsins. Mammals lost Rh2 and SWS2 classes during the 10529: 9475: 7527: 3137: 1182: 2467:

Hargrave PA, McDowell JH, Curtis DR, Wang JK, Juszczak E, Fong SL, et al. (1983). "The structure of bovine rhodopsin".

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gene. In the human retina, its function is unknown. In the mouse, it photo-entrains the retina and cornea at least ex vivo.

11282: 9703: 9515: 8985: 8723: 8718: 8713: 8708: 8703: 8361: 2835:

Choe HW, Kim YJ, Park JH, Morizumi T, Pai EF, Krauss N, et al. (March 2011). "Crystal structure of metarhodopsin II".

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residues are highly conserved between all opsin groups, indicating that they serve important functions and thus are called

7903:"Functional characterization of flavobacteria rhodopsins reveals a unique class of light-driven chloride pump in bacteria" 6659:"Co-expression of VAL- and TMT-opsins uncovers ancient photosensory interneurons and motorneurons in the vertebrate brain" 1270:

region of the brain. It is sensitive to approximately 500 nm , found in most vertebrate classes, but not in mammals.

10516: 9165: 5652:"Adaptation of pineal expressed teleost exo-rod opsin to non-image forming photoreception through enhanced Meta II decay" 5615:

Mano H, Kojima D, Fukada Y (November 1999). "Exo-rhodopsin: a novel rhodopsin expressed in the zebrafish pineal gland".

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Photoreceptors can be classified several ways, including function (vision, phototaxis, photoperiodism, etc.), type of

1120:. Similarly, "R-opsin (rhabdomeric)" includes melanopsin even though it does not occur on rhabdomeres in vertebrates. 11090: 11085: 11080: 11075: 11070: 11065: 11060: 11055: 9278: 9073: 9068: 9063: 8699: 7234:"Amphioxus homologs of Go-coupled rhodopsin and peropsin having 11-cis- and all-trans-retinals as their chromophores" 1655: 1060:

opsins (r-opsins, rhabopsins), the xenopsins, the nessopsins, and the tetraopsins. Four of these subclades occur in

10872: 10867: 9807: 9802: 8883: 8878: 7459:"Peropsin, a novel visual pigment-like protein located in the apical microvilli of the retinal pigment epithelium" 1651: 30:

Three-dimensional structure of cattle rhodopsin. The seven transmembrane domains are shown in varying colors. The

11051: 10958: 9812: 9058: 8813: 1848:, are used by various bacterial groups to harvest energy from light to carry out metabolic processes using a non- 415:

Most known opsins have the retinal binding lysine except some among the tetraopins, The outgroup contains other

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but not in vision. Humans have in total nine opsins. Beside vision and light perception, opsins may also sense

5993:"Diversification of non-visual photopigment parapinopsin in spectral sensitivity for diverse pineal functions" 1492:

the opsins expressed in the lateral and the compound eyes are 99% identical and presumably diverged recently.

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Hao W, Fong HK (May 1996). "Blue and ultraviolet light-absorbing opsin from the retinal pigment epithelium".

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Animal visual opsins are traditionally classified as either ciliary or rhabdomeric. Ciliary opsins, found in

162:-retinal only blocks the binding pocket and does not activate the opsin. The opsin is only activated when 11- 10898: 9238: 9233: 8469: 8464: 8459: 8449: 8444: 8439: 1705:

use animal opsins, exclusively. No opsins have been found outside these groups (for instance in plants, or

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Animal opsins (also known as type 2 opsins) are members of the seven-transmembrane-domain proteins of the

589:, the receptor can still be activated but less efficiently, this mutation even abolishes activation in the 7762:"Systematic study on G-protein couple receptor prototypes: did they really evolve from prokaryotic genes?" 7085:"Neuropsin (OPN5)-mediated photoentrainment of local circadian oscillators in mammalian retina and cornea" 3599:

Senthilan PR, Piepenbrock D, Ovezmyradov G, Nadrowski B, Bechstedt S, Pauls S, et al. (August 2012).

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purposes. Sensory rhodopsins exist in Halobacteria that induce a phototactic response by interacting with

10432: 8999: 8994: 8455: 8435: 8332: 1130: 295: 5699:

Okano T, Yoshizawa T, Fukada Y (November 1994). "Pinopsin is a chicken pineal photoreceptive molecule".

4622:"Identification of a novel asthma susceptibility gene on chromosome 1qter and its functional evaluation" 3754:"Relocating the active-site lysine in rhodopsin and implications for evolution of retinylidene proteins" 559:), cattle rhodopsin does not activate the G-protein. Such a mutation also reduces the activation of the 9432: 9427: 9283: 9273: 9268: 9253: 9248: 9221: 9047: 9042: 9037: 8948: 8485: 8480: 8475: 8388: 8095: 7962:"Of ion pumps, sensors and channels - perspectives on microbial rhodopsins between science and history" 7281:

Jiang M, Pandey S, Fong HK (December 1993). "An opsin homologue in the retina and pigment epithelium".

6334:"Ciliary and rhabdomeric photoreceptor-cell circuits form a spectral depth gauge in marine zooplankton" 5759: 1904:

and thus are activated by light directly, while animal opsins activate G-proteins, which then activate

1754: 1732: 1674: 1591: 1050: 1008: 590: 416: 276: 119: 51: 7332:"The retinal G protein-coupled receptor (RGR) enhances isomerohydrolase activity independent of light" 6332:

Verasztó C, Gühmann M, Jia H, Rajan VB, Bezares-Calderón LA, Piñeiro-Lopez C, et al. (May 2018).

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Tarttelin EE, Fransen MP, Edwards PC, Hankins MW, Schertler GF, Vogel R, et al. (November 2011).

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Rawlinson KA, Lapraz F, Ballister ER, Terasaki M, Rodgers J, McDowell RJ, et al. (October 2019).

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opsin I (NOPI), Chlamydomonas sensory rhodopsins A (CSRA), Chlamydomonas sensory rhodopsins B (CSRB),

9469: 9464: 9459: 9229: 9115: 8943: 8925: 8906: 8899: 8418: 8353: 6386:

Gühmann M, Jia H, Randel N, Verasztó C, Bezares-Calderón LA, Michiels NK, et al. (August 2015).

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D'Aniello S, Delroisse J, Valero-Gracia A, Lowe EK, Byrne M, Cannon JT, et al. (December 2015).

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Quiroga Artigas G, Lapébie P, Leclère L, Takeda N, Deguchi R, Jékely G, et al. (January 2018).

4073:"The endogenous chromophore of retinal G protein-coupled receptor opsin from the pigment epithelium" 1056:

Animal opsins fall phylogenetically into five groups: The ciliary opsins (cilopsins, c-opsins), the

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Most chromopsins have also the retinal binding lysine except the nemopsins, where it is replaced by

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The seven transmembrane α-helical domains in opsins are connected by three extra-cellular and three

11024: 10893: 10853: 10499: 9423: 9385: 9244: 9033: 8957: 8911: 8401: 4929:"Evolution of mammalian Opn5 as a specialized UV-absorbing pigment by a single amino acid mutation" 1969: 1927: 83: 5991:

Koyanagi M, Wada S, Kawano-Yamashita E, Hara Y, Kuraku S, Kosaka S, et al. (September 2015).

5883:"Parapinopsin, a novel catfish opsin localized to the parapineal organ, defines a new gene family" 5750:

Nakane Y, Yoshimura T (February 2019). "Photoperiodic Regulation of Reproduction in Vertebrates".

9757: 9752: 9747: 9742: 9737: 9697: 9692: 9609: 9604: 9599: 9589: 9455: 9339: 9307: 9302: 9264: 9259: 9170: 8894: 8137: 8036:

Zhang F, Vierock J, Yizhar O, Fenno LE, Tsunoda S, Kianianmomeni A, et al. (December 2011).

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Galés C, Kowalski-Chauvel A, Dufour MN, Seva C, Moroder L, Pradayrol L, et al. (June 2000).

1960: 1869: 1142: 560: 384: 178:-retinal, the receptor activating form, causing conformal changes in the opsin, which activate a 5112:

Liegertová M, Pergner J, Kozmiková I, Fabian P, Pombinho AR, Strnad H, et al. (July 2015).

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Ramirez MD, Pairett AN, Pankey MS, Serb JM, Speiser DI, Swafford AJ, Oakley TH (December 2016).

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Oroshnik W (June 1956). "The Synthesis and Configuration of Neo-B Vitamin A and Neoretinine b".

9410: 9405: 9322: 9317: 8916: 8517: 8512: 6657:

Fischer RM, Fontinha BM, Kirchmaier S, Steger J, Bloch S, Inoue D, et al. (11 June 2013).

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Nissilä J, Mänttäri S, Särkioja T, Tuominen H, Takala T, Timonen M, Saarela S (November 2012).

2532: 586: 540: 316: 95: 7517: 5114:"Cubozoan genome illuminates functional diversification of opsins and photoreceptor evolution" 3870:"Role of the conserved NPxxY(x)5,6F motif in the rhodopsin ground state and during activation" 10955: 9793: 9777: 9772: 9767: 9733: 9688: 9585: 9448: 9443: 9395: 9298: 9293: 9080: 8964: 8807: 8802: 8797: 8786: 8781: 8776: 8771: 8522: 8507: 8384: 8281: 8246: 8088: 6535:"Homologs of vertebrate Opn3 potentially serve as a light sensor in nonphotoreceptive tissue" 5556:

Gulati S, Jastrzebska B, Banerjee S, Placeres ÁL, Miszta P, Gao S, et al. (March 2017).

1718: 1678: 1574: 1347: 1020: 1016: 298:. Even so most opsins have Lys296, some have lost it during evolution: In the nemopsins from 183: 7330:

Wenzel A, Oberhauser V, Pugh EN, Lamb TD, Grimm C, Samardzija M, et al. (August 2005).

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Kato M, Sugiyama T, Sakai K, Yamashita T, Fujita H, Sato K, et al. (18 November 2016).

3452:"Divergent seven transmembrane receptors are candidate chemosensory receptors in C. elegans" 3334:

Porter ML, Blasic JR, Bok MJ, Cameron EG, Pringle T, Cronin TW, Robinson PR (January 2012).

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Katana R, Guan C, Zanini D, Larsen ME, Giraldo D, Geurten BR, et al. (September 2019).

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The first invertebrate panopsin was found in the ciliary photoreceptor cells of the annelid

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two distinct LWS opsins (LWS and MWS), leaving humans with 3 photopsins in 2 classes: SWS1 (

11005: 10663: 9975: 9798: 9783: 9360: 9313: 8990: 8969: 8754: 8749: 8744: 8739: 8734: 8127: 7914: 7614: 7559: 7470: 7096: 7037: 6975: 6877: 6818: 6759: 6608: 6546: 6399: 6184: 6051: 5945: 5932:

Koyanagi M, Kawano E, Kinugawa Y, Oishi T, Shichida Y, Tamotsu S, Terakita A (April 2004).

5708: 5569: 5520: 5296: 5125: 5063: 4840: 4385: 4121: 3881: 3765: 3557: 3512: 3281: 3221: 2898: 2844: 2790: 2735: 2631: 2580: 2524: 2425: 2370: 2243: 2194: 2139: 2088: 1917: 1818: 1740: 1647: 1174: 1163: 63: 9649: 9644: 9639: 7026:"Opn5 is a UV-sensitive bistable pigment that couples with Gi and Gq subtype of G protein" 4927:

Yamashita T, Ono K, Ohuchi H, Yumoto A, Gotoh H, Tomonari S, et al. (February 2014).

3717: 8: 10828: 9763: 9654: 9438: 9401: 8866: 8495: 8427: 8300: 8250: 5767: 1932: 1877: 1758: 1682: 1629: 1024: 199: 20: 7918: 7618: 7563: 7474: 7100: 7041: 6979: 6881: 6822: 6805:

Mason B, Schmale M, Gibbs P, Miller MW, Wang Q, Levay K, et al. (5 December 2012).

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Such function does not need to be light detection, as some opsins are also involved in

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2010: 1993: 1523:, the Go-opsins, and the chromopsins. The chromopsins consist of seven subgroups: the 712:

differs between different opsin groups and between opsin groups of different species.

632: 66:, but are usually still called opsins regardless. Most prominently, they are found in 10913: 10857: 10503: 10233: 10228: 9683: 9380: 8729: 8067: 8018: 7983: 7942: 7883: 7834: 7793: 7742: 7691: 7642: 7575: 7523: 7498: 7493: 7458: 7439: 7404: 7353: 7290: 7255: 7214: 7191:

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7173: 7124: 7065: 7003: 6998: 6963: 6944: 6895: 6846: 6787: 6728: 6690: 6636: 6574: 6515: 6466: 6417: 6365: 6314: 6259: 6200: 6157: 6116: 6067: 6024: 5973: 5914: 5855: 5814: 5771: 5724: 5681: 5632: 5597: 5538: 5489: 5440: 5384: 5324: 5262: 5206: 5151: 5091: 5009: 4980:"Evidence for distributed light sensing in the skin of cuttlefish, Sepia officinalis" 4960: 4909: 4868: 4802: 4750: 4701: 4643: 4602: 4534: 4530: 4491: 4448: 4444: 4413: 4341: 4298: 4263: 4189: 4137: 4094: 4050: 4009: 3960: 3909: 3839: 3793: 3731: 3679: 3622: 3585: 3573: 3530: 3473: 3468: 3451: 3429: 3365: 3307: 3251: 3239: 3179: 3174: 3157: 3133: 3098: 3039: 2914: 2860: 2806: 2763: 2704: 2647: 2596: 2550: 2484: 2441: 2398: 2312: 2271: 2155: 2104: 2061: 2015: 1937: 1861: 1845: 1807: 1694: 1578:

however, a Go-opsin is expressed in the rhabdomeric photoreceptor cells of the eyes.

1373:= 377 - 502 nm). Thus, not unsurprisingly, a second but cyan sensitive c-opsin ( 649:(K) 296 is highlighted with a gray background, which is replaced in the nemopsins by 388: 357: 75: 7711:"The evolutionary relationship between microbial rhodopsins and metazoan rhodopsins" 7587: 7267: 6388:"Spectral Tuning of Phototaxis by a Go-Opsin in the Rhabdomeric Eyes of Platynereis" 6079: 5867: 5783: 4546: 4503: 4353: 4310: 3851: 3810: 3485: 3400:"The Last Common Ancestor of Most Bilaterian Animals Possessed at Least Nine Opsins" 3191: 2818: 2496: 2027: 1949: 9708: 9630: 9480: 8342: 8231: 8057: 8049: 8010: 7973: 7932: 7922: 7873: 7865: 7824: 7783: 7773: 7732: 7722: 7681: 7673: 7632: 7622: 7567: 7488: 7478: 7431: 7394: 7384: 7343: 7245: 7204: 7163: 7155: 7114: 7104: 7055: 7045: 6993: 6983: 6964:"Opsins from the lateral eyes and ocelli of the horseshoe crab, Limulus polyphemus" 6934: 6926: 6885: 6836: 6826: 6777: 6767: 6746:

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3229: 3210:"Chromophore-Independent Roles of Opsin Apoproteins in Drosophila Mechanoreceptors" 3169: 3125: 3088: 3080: 3029: 3019: 2945: 2906: 2872: 2852: 2798: 2753: 2743: 2694: 2686: 2675:"Studies on rhodopsin. VIII. Retinylidenemethylamine, an indicator yellow analogue" 2659: 2639: 2608: 2588: 2542: 2476: 2453: 2433: 2388: 2378: 2359:"HINDERED CIS ISOMERS OF VITAMIN A AND RETINENE: THE STRUCTURE OF THE NEO-b ISOMER" 2339: 2302: 2261: 2251: 2232:"Hindered Cis Isomers of Vitamin a and Retinene: The Structure of the Neo-B Isomer" 2216: 2202: 2167: 2147: 2116: 2096: 2053: 2005: 1884: 1830: 1508: 1504: 1470: 1279: 667: 564: 368: 91: 5558:"Photocyclic behavior of rhodopsin induced by an atypical isomerization mechanism" 5231:"Extraocular, rod-like photoreceptors in a flatworm express xenopsin photopigment" 5050:

Yu C, Li Y, Zhang X, Huang X, Malyarchuk V, Wang S, et al. (September 2014).

118:

Animal opsins detect light and are the molecules that allow us to see. Opsins are

11287: 11101: 10888: 10697: 9986: 9668: 9635: 9375: 8672: 8657: 8652: 8647: 8637: 8632: 8627: 8622: 8617: 7978: 7961: 7550:

Fernald RD (September 2006). "Casting a genetic light on the evolution of eyes".

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6111: 6094: 4853: 4398: 3525: 3500: 2910: 2546: 1965: 1956: 1892: 1841: 1834: 1822: 1749: 1659: 1204: 1155: 489: 364: 5834:"Nonvisual Opsins and the Regulation of Peripheral Clocks by Light and Hormones" 1595: 1250:

Pineal opsins have a wide range of expression in the brain, most notably in the

1219: 1076:, the Go-opsins, and the chromopsins. The chromopsins have seven subgroups: the 10974: 9834: 9662: 8889: 8682: 8677: 8667: 8643: 8613: 8608: 8053: 7907: