Phototransduction Motifs and Variations

Yau, King Wai; Hardie, Roger C.

doi:10.1016/j.cell.2009.09.029

Cited by 389 publications

(432 citation statements)

References 149 publications

(230 reference statements)

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“…More recently, members of the TRP family have been implicated in a wide range of sensory functions, including photosensation, chemosensation, thermosensation, and nociception (6,7). In mammalian phototransduction, TRPC channels mediate a light-sensitive current in intrinsically photoreceptive retinal ganglion cells, which are responsible for nonimage-forming visual processes in the human retina (8)(9)(10)(11). TRP channels are also expressed in the epidermis and are activated by noxious compounds, acidic pH, and temperature (12)(13)(14).…”

mentioning

confidence: 99%

“…The ability of both forms of retinal to evoke a photocurrent might be because of the conversion of all-trans to cis-retinal in melanocytes, possibly using the retinoid isomerase RPE65, which is expressed in skin (19) and catalyzes the conversion of transretinal to the cis-conformation, as in the visual cycle in mammalian rod and cone cells (10). Alternatively, the pigment mediating UVR phototransduction in HEMs could drive signaling using either cis-or trans-retinal, similar to the bistable opsins required for nonvisual phototransduction in the mammalian retina or invertebrate phototransduction (10,20).…”

mentioning

confidence: 99%

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UV light phototransduction activates transient receptor potential A1 ion channels in human melanocytes

Bellono

Kammel

Zimmerman

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

130

139

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Human skin is constantly exposed to solar ultraviolet radiation (UVR), the most prevalent environmental carcinogen. Humans have the unique ability among mammals to respond to UVR by increasing their skin pigmentation, a protective process driven by melanin synthesis in epidermal melanocytes. The molecular mechanisms used by melanocytes to detect and respond to longwavelength UVR (UVA) are not well understood. We recently identified a UVA phototransduction pathway in melanocytes that is mediated by G protein-coupled receptors and leads to rapid calcium mobilization. Here we report that in human epidermal melanocytes physiological doses of UVR activate a retinal-dependent current mediated by transient receptor potential A1 (TRPA1) ion channels. The TRPA1 photocurrent is UVA-specific and requires G protein and phospholipase C signaling, thus contributing to UVAinduced calcium responses to mediate downstream cellular effects and providing evidence for TRPA1 function in mammalian phototransduction. Remarkably, TRPA1 activation is required for the UVR-induced and retinal-dependent early increase in cellular melanin. Our results show that TRPA1 is essential for a unique extraocular phototransduction pathway in human melanocytes that is activated by physiological doses of UVR and results in early melanin synthesis.

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mentioning

confidence: 99%

mentioning

confidence: 99%

UV light phototransduction activates transient receptor potential A1 ion channels in human melanocytes

Bellono

Kammel

Zimmerman

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

130

139

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“…G-protein-mediated phototransduction cascade has been elucidated for the pigments belonging to four out of the eight groups. 2,4 Recently, we discovered functional and evolutionary relationships between phototransduction cascades and photoreceptor cell types, which were distinguished based on morphological characteristics of the photoreceptive portion of the photoreceptor cells, namely the ciliary and rhabdomeric photoreceptor cells. 3 Vertebrate visual pigments, which are Gt-coupled opsin-based pigments, are found in rods and cones and activate transducin (Gt), which in turn activates phosphodiesterase, which hydrolyzes cGMP to 5 GMP.…”

Section: The Diversity Of Opsins and The Classification Of Phototransmentioning

confidence: 99%

“…This cascade leads to a depolarizing response of the photoreceptor cells. 4 In Drosophila, depletion of PIP2 underlies opening the transient receptor potential (TRP)/transient receptor potential-like (TRPL) channels to generate a depolarizing response. 9 On the other hand, a DG-related unsaturated fatty acid can also open the channels.…”

Section: The Diversity Of Opsins and The Classification Of Phototransmentioning

confidence: 99%

“…4 Ascidians, some of the invertebrates most closely related to vertebrates, have an opsin-based pigment Ci-opsin1, which is related to vertebrate visual and nonvisual pigments (Figure 3), but a transducin or a visual arrestin gene has not been found in the genomes of ascidians. Interestingly, Ciopsin1 colocalizes with a β-arrestin-like arrestin, the molecular properties of which are similar to those of the vertebrate nonvisual arrestin, β-arrestin.…”

Section: The Evolutionary Relationship Between Opsins and Other Photomentioning

confidence: 99%

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Evolution and diversity of opsins

Terakita

Kawano‐Yamashita

Koyanagi

2011

WIREs Membr Transp Signal

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Many animals capture light information via opsin-based pigments. Several thousands of opsins have been identified thus far and the opsin family is divided into eight groups. Members belonging to four out of the eight groups have been elucidated to couple to transducin, Go, Gs, and Gq, respectively, in photoreceptor cells. Accumulated evidence suggests a novel classification of the animal phototransductions, cyclic nucleotide signaling mediated by transducin, Go or Gs in ciliary photoreceptor cells and phosphoinositol signaling mediated by Gq in rhabdomeric photoreceptor cells. Varied opsin-based pigments are spectroscopically classified into two types, bleaching and bistable pigments; that is, the photoproduct of vertebrate visual pigments dissociates its chromophore retinal over time and bleaches, whereas most other opsin-based pigments convert to a stable photoproduct, which can revert to original dark state by subsequent light absorption. Mutational analyses of the both types of pigments implied that during molecular evolution of the vertebrae visual pigments, displacement of the counterion, important amino acid residue for visible light absorption of opsin-based pigment, resulted in not only unique bleaching property but also acquisition of red-sensitive visual pigment and higher G-protein activation ability generated by larger light-induced conformational change of the pigment. Interestingly, a bleaching pigment rhodopsin and parapinopsin, which closely relates to the vertebrate visual pigment but has a bistable nature, couple to visual arrestin and β arrestin, respectively, in the lamprey pineal organ, suggesting the bleaching property also might facilitate the evolution of visual arrestin which is specialized for vertebrate visual function. 

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Evolution of Visual Performance‐associated Genes inDrosophila

Friedrich

2010

Encyclopedia of Life Sciences

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The leading model of insect vision, the fruitfly Drosophila melanogaster , is a representative of the higher Diptera (Brachycera), which excel by swift flight abilities, one of the fastest photoresponse mechanisms known and a unique form of neural superposition optics. Recent gene‐specific as well as comparative genomic investigations have begun to yield first insights into the genetic origins of Drosophila visual organisation and performance. These studies suggest discrete stages in the molecular evolution of Drosophila vision culminating in changes that enhanced the speed and versatility of diurnal vision specifically during the early evolution of the higher Diptera. Comparative genomic analysis revealed that gene duplication played an unusually important role during this final stage of Drosophila vision evolution. Select gene‐specific studies, however, also uncovered specific cis ‐regulatory and coding region changes that were of key importance in the evolution the Drosophila phototransduction and retinal organisation. Key Concepts: The shared deployment of the phototransduction protein machinery in the photoreceptors of highly diversified visual organs in Drosophila (the larval eyes, ocelli and the adult compound eye) may impose adaptive constraints. In contrast to the detailed mechanistic understanding of irradiance and color vision in Drosophila , the ecological role and significance of these sophisticated visual capacities is still little known in Drosophila and the related Diptera. The complex retinal organisation of Drosophila is representative of all members of the species‐rich higher Diptera suggesting strong functional or developmental constraints. Phylogenetic evidence indicates a correlation of significant structural and molecular changes in the visual system of Drosophila and the higher Diptera the cause of which requires further comporative research. Gene duplication played a critical role in the early visual evolution of the higher Diptera. The evolution of the Drosophila visual system is a paradigm example of the combined effects of cis ‐regulatory and coding sequence evolution. Select mechanisms of the Drosophila photoresponse are likely to differ in insect species outside the higher Diptera complicating functional gene orthology inferrences and warranting further research in other models of insect vision.

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Phototransduction Motifs and Variations

Cited by 389 publications

References 149 publications

UV light phototransduction activates transient receptor potential A1 ion channels in human melanocytes

UV light phototransduction activates transient receptor potential A1 ion channels in human melanocytes

Evolution and diversity of opsins

Evolution of Visual Performance‐associated Genes inDrosophila

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