Melanopsin and inner retinal photoreception

Bailes, Helena J.; Lucas, Robert J.

doi:10.1007/s00018-009-0155-7

Cited by 104 publications

(70 citation statements)

References 148 publications

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“…In fact, rods and cones use a cascade involving cyclic guanyl monophosphate as a second messenger whereas rhabdomeric photoreceptors use a phosphoinositide-signaling cascade involving the enzyme phospholipase C (PLC) (41). Retinal photoreception in mammals includes a subset of retinal ganglion cells that are able to respond to light even in the absence of synaptic inputs (42). These cells, called "intrinsically photosensitive retinal ganglion cells" (ipRGCs), use melanopsin as photopigment and send their axons directly to the suprachiasmatic nucleus, the site of the primary circadian pacemaker in mammals (18,41).…”

Section: Discussionmentioning

confidence: 99%

Fly cryptochrome and the visual system

Mazzotta

Rossi

Leonardi

et al. 2013

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

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Cryptochromes are flavoproteins, structurally and evolutionarily related to photolyases, that are involved in the development, magnetoreception, and temporal organization of a variety of organisms. Drosophila CRYPTOCHROME (dCRY) is involved in light synchronization of the master circadian clock, and its C terminus plays an important role in modulating light sensitivity and activity of the protein. The activation of dCRY by light requires a conformational change, but it has been suggested that activation could be mediated also by specific "regulators" that bind the C terminus of the protein. This C-terminal region harbors several protein-protein interaction motifs, likely relevant for signal transduction regulation. Here, we show that some functional linear motifs are evolutionarily conserved in the C terminus of cryptochromes and that class III PDZ-binding sites are selectively maintained in animals. A coimmunoprecipitation assay followed by mass spectrometry analysis revealed that dCRY interacts with Retinal Degeneration A (RDGA) and with Neither Inactivation Nor Afterpotential C (NINAC) proteins. Both proteins belong to a multiprotein complex (the Signalplex) that includes visualsignaling molecules. Using bioinformatic and molecular approaches, dCRY was found to interact with Neither Inactivation Nor Afterpotential C through Inactivation No Afterpotential D (INAD) in a light-dependent manner and that the CRY-Inactivation No Afterpotential D interaction is mediated by specific domains of the two proteins and involves the CRY C terminus. Moreover, an impairment of the visual behavior was observed in fly mutants for dCRY, indicative of a role, direct or indirect, for this photoreceptor in fly vision.

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Section: Discussionmentioning

confidence: 99%

Fly cryptochrome and the visual system

Mazzotta

Rossi

Leonardi

et al. 2013

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

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“…It should be noted that non-mammalian melanopsin also shows peak spectral sensitivity ~480 nm, in close agreement with mammalian ipRGCs (Koyanagi et al 2005;Torii et al 2007;Davies et al 2011). Thus, it is now generally agreed that mammalian melanopsin maximally absorbs light at ~480 nm although direct in vitro spectroscopic analysis of purified mammalian melanopsin is still needed (Bailes and Lucas 2010).…”

Section: Melanopsin Is a Photopigmentmentioning

confidence: 68%

Intrinsically photosensitive retinal ganglion cells

Pickard

Sollars

2010

Sci. China Life Sci.

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Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light in the absence of all rod and cone photoreceptor input. The existence of these ganglion cell photoreceptors, although predicted from observations scattered over many decades, was not established until it was shown that a novel photopigment, melanopsin, was expressed in retinal ganglion cells of rodents and primates. Phototransduction in mammalian ipRGCs more closely resembles that of invertebrate than vertebrate photoreceptors and appears to be mediated by transient receptor potential channels. In the retina, ipRGCs provide excitatory drive to dopaminergic amacrine cells and ipRGCs are coupled to GABAergic amacrine cells via gap junctions. Several subtypes of ipRGC have been identified in rodents based on their morphology, physiology and expression of molecular markers. ipRGCs convey irradiance information centrally via the optic nerve to influence several functions including photoentrainment of the biological clock located in the hypothalamus, the pupillary light reflex, sleep and perhaps some aspects of vision. In addition, ipRGCs may also contribute irradiance signals that interface directly with the autonomic nervous system to regulate rhythmic gene activity in major organs of the body. Here we review the early work that provided the motivation for searching for a new mammalian photoreceptor, the ground-breaking discoveries, current progress that continues to reveal the unusual properties of these neuron photoreceptors, and directions for future investigation.Keywords: Melanopsin, Circadian rhythms, Suprachiasmatic nucleus, Retina digitalcommons.unl.edu P i c k a r d & S o l l a r S i n R e v P h y s i o l B i o c h e m P h a R m a c o l1 6 2 ( 2 0 1 2 ) Early Hints of a Third Photoreceptor in the Mammalian RetinaThe perception of shapes, color and objects moving in the world begins in the outer retina where light is absorbed by photopigments that are integral membrane apoproteins (opsins) covalently linked to a retinaldehyde chromophore in the rod and cone photoreceptors. The capturing of photons by rod and cone photoreceptors initiates a signaling cascade in which photon capture is converted into an electrical signal. The simplest common pathway these signals take from the eye to the brain is from the photoreceptors to bipolar cells to ganglion cells. Retinal ganglion cells (RGCs) convey the signals centrally as action potentials, transmitted via their axons in the optic nerve, to higher brain regions for integration and the further processing required for conscious visual perception (Fig. 1). Among non-mammalian vertebrates, photoreceptors are also found in locations outside the retina, including the pineal gland and in the brain itself. These extra-ocular photoreceptors mediate tasks not associated directly with visual perception (non-image forming functions such as hormone regulation). However, since the pioneering descriptions of the vertebrate retina by Santiago Ramón y Cajal in the late 1800s, it was believed that t...

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“…10 Interestingly, melanopsin, an opsin gene orthologous to invertebrate Gq-coupled visual pigments, has spectroscopic characteristics almost identical to those of invertebrate Gq-coupled opsin-based pigments and drives the Gqmediated phototransduction cascade. [11][12][13][14][15][16] Melanopsin localizes to rhabdomeric photoreceptor cells in amphioxus 17 and mammalian intrinsically photosensitive retinal ganglion cells, [18][19][20][21] which are thought to have shared a common ancestral type with modern-day rhabdomeric photoreceptor cells. 22 As mentioned, cnidarian, molluscan, and vertebrate ciliary photoreceptor cells contain different sets of opsin-based pigments, G-proteins, and effector enzymes, but they employ the same type of second messenger, a cyclic nucleotide (cAMP and cGMP), and utilize the CNG channel.…”

Section: The Diversity Of Opsins and The Classification Of Phototransmentioning

confidence: 99%

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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Melanopsin and inner retinal photoreception

Cited by 104 publications

References 148 publications

Fly cryptochrome and the visual system

Fly cryptochrome and the visual system

Intrinsically photosensitive retinal ganglion cells

Evolution and diversity of opsins

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