Expression and comparative characterization of Gq‐coupled invertebrate visual pigments and melanopsin

Terakita, Akihisa; Tsukamoto, Hisao; Koyanagi, Mitsumasa; Sugahara, Michio; Yamashita, Takahiro; Shichida, Yoshinori

doi:10.1111/j.1471-4159.2007.05184.x

Cited by 88 publications

(107 citation statements)

References 42 publications

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“…Heterologously expressed melanopsin from the protochordate Amphioxus does appear to have a red-shifted photoreversal mechanism (49,50). Difference spectra of recombinant Amphioxus melanopsin purified from HEK293 cells and exposed to alternating blue and orange light indicate a reversal wavelength near 515 nm.…”

Section: Discussionmentioning

confidence: 99%

Melanopsin Is Highly Resistant to Light and Chemical Bleaching in Vivo

Sexton

Golczak

Palczewski

et al. 2012

Journal of Biological Chemistry

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Background:The mechanism of melanopsin chromophore regeneration is poorly understood. Results: In situ melanopsin was partially bleached by high-intensity UV light or hydroxylamine and could be restored by cis-retinal only. Conclusion: Melanopsin resistance to light and UV bleaching is consistent with a bistable mechanism of chromophore regeneration. Significance: Further evidence suggests that melanopsin behaves as a bistable pigment in situ.

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Section: Discussionmentioning

confidence: 99%

Melanopsin Is Highly Resistant to Light and Chemical Bleaching in Vivo

Sexton

Golczak

Palczewski

et al. 2012

Journal of Biological Chemistry

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“…G protein activation by the Opn3 homolog-based pigments was evaluated by measuring the amount of guanosine 5′-O-(3-thiotriphosphate) (GTPγS) bound to G i , G o , G t , G q , or G s , as described (21,23). G i , G o , and G t were prepared as described (23).…”

mentioning

confidence: 99%

Homologs of vertebrate Opn3 potentially serve as a light sensor in nonphotoreceptive tissue

Koyanagi

Takada

Nagata

et al. 2013

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

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214

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Most opsins selectively bind 11-cis retinal as a chromophore to form a photosensitive pigment, which underlies various physiological functions, such as vision and circadian photoentrainment. Recently, opsin 3 (Opn3), originally called encephalopsin or panopsin, and its homologs were identified in various tissues including brain, eye, and liver in both vertebrates and invertebrates, including human. Because Opn3s are mainly expressed in tissues that are not considered to contain sufficient amounts of 11-cis retinal to form pigments, the photopigment formation ability of Opn3 has been of interest. Here, we report the successful expression of Opn3 homologs, pufferfish teleost multiple tissue opsin (PufTMT) and mosquito Opn3 (MosOpn3) and show that these proteins formed functional photopigments with 11-cis and 9-cis retinals. The PufTMT-and MosOpn3-based pigments have absorption maxima in the blue-to-green region and exhibit a bistable nature. These Opn3 homolog-based pigments activate G i -type and G o -type G proteins light dependently, indicating that they potentially serve as light-sensitive G i /G o -coupled receptors. We also demonstrated that mammalian cultured cells transfected with the MosOpn3 or PufTMT became light sensitive without the addition of 11-cis retinal and the photosensitivity retained after the continuous light exposure, showing a reusable pigment formation with retinal endogenously contained in culture medium. Interestingly, we found that the MosOpn3 also acts as a light sensor when constituted with 13-cis retinal, a ubiquitously present retinal isomer. Our findings suggest that homologs of vertebrate Opn3 might function as photoreceptors in various tissues; furthermore, these Opn3s, particularly the mosquito homolog, could provide a promising optogenetic tool for regulating cAMP-related G protein-coupled receptor signalings.rhodopsin | phototransduction | nonvisual photoreception | opsin diversity M ost opsins bind 11-cis retinal as a chromophore to form a photosensitive pigment (opsin-based pigment) that serves as a light-sensitive G protein-coupled receptor (GPCR). The 11-cis to all-trans isomerization of the chromophore in an opsinbased pigment upon light absorption triggers G protein activation (1-4), and the photoreception of the opsin-based pigment initiates vision and nonvisual functions, including circadian entrainment and pupil responses. Several thousand opsins have been identified, and they are phylogenetically classified into eight groups based on the members that have existed early in animal evolution (5). The phylogenetic classification of each opsin also roughly corresponds to its molecular function. The G t -coupled opsin group contains vertebrate visual pigments, which activate transducin (G t )-type G proteins, and some nonvisual pigments, such as pinopsin, VA-opsin, parapinopsin, and parietopsin (1-4). The G q -coupled opsin group is composed of the visual pigments from many invertebrates, such as insects and cephalopods, and the vertebrate opsin 4 (Opn4) homologs (melanops...

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“…To regain light sensitivity, the enzymatic retinoid cycle within the retinal pigment epithelium is required for regeneration of the chromophore back to the lightsensitive state. In contrast, melanopsin is a dual-state photopigment, in which photons drive both processes of phototransduction and part of chromophore regeneration (10)(11)(12). Recent rodent and human data suggest that exposure to longer wavelength light (590-620 nm; orange-red) triggers melanopsin chromophore regeneration and increases overall subsequent intrinsic photosensitivity of ipRGCs (13,14).…”

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confidence: 99%

Photic memory for executive brain responses

Chellappa

Meyer

et al. 2014

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

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Light is a powerful stimulant for human alertness and cognition, presumably acting through a photoreception system that heavily relies on the photopigment melanopsin. In humans, evidence for melanopsin involvement in light-driven cognitive stimulation remains indirect, due to the difficulty to selectively isolate its contribution. Therefore, a role for melanopsin in human cognitive regulation remains to be established. Here, sixteen participants underwent consecutive and identical functional MRI recordings, during which they performed a simple auditory detection task and a more difficult auditory working memory task, while continuously exposed to the same test light (515 nm). We show that the impact of test light on executive brain responses depends on the wavelength of the light to which individuals were exposed prior to each recording. Test-light impact on executive responses in widespread prefrontal areas and in the pulvinar increased when the participants had been exposed to longer (589 nm), but not shorter (461 nm), wavelength light, more than 1 h before. This wavelength-dependent impact of prior light exposure is consistent with recent theories of the light-driven melanopsin dual states. Our results emphasize the critical role of light for cognitive brain responses and are, to date, the strongest evidence in favor of a cognitive role for melanopsin, which may confer a form of "photic memory" to human cognitive brain function.fMRI | non-image-forming

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Expression and comparative characterization of Gq‐coupled invertebrate visual pigments and melanopsin

Cited by 88 publications

References 42 publications

Melanopsin Is Highly Resistant to Light and Chemical Bleaching in Vivo

Melanopsin Is Highly Resistant to Light and Chemical Bleaching in Vivo

Homologs of vertebrate Opn3 potentially serve as a light sensor in nonphotoreceptive tissue

Photic memory for executive brain responses

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