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Wijayaratna D, Sacchetta F, Pedraza-González L, Fanelli F, Sugihara T, Koyanagi M, Piyawardana S, Ghotra K, Thotamune W, Terakita A, Olivucci M, Karunarathne A. In-silico predicted mouse melanopsins with blue spectral shifts deliver efficient subcellular signaling. Cell Commun Signal 2024; 22:394. [PMID: 39118111 PMCID: PMC11312219 DOI: 10.1186/s12964-024-01753-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 07/17/2024] [Indexed: 08/10/2024] Open
Abstract
Melanopsin is a photopigment belonging to the G Protein-Coupled Receptor (GPCR) family expressed in a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) and responsible for a variety of processes. The bistability and, thus, the possibility to function under low retinal availability would make melanopsin a powerful optogenetic tool. Here, we aim to utilize mouse melanopsin to trigger macrophage migration by its subcellular optical activation with localized blue light, while simultaneously imaging the migration with red light. To reduce melanopsin's red light sensitivity, we employ a combination of in silico structure prediction and automated quantum mechanics/molecular mechanics modeling to predict minimally invasive mutations to shift its absorption spectrum towards the shorter wavelength region of the visible spectrum without compromising the signaling efficiency. The results demonstrate that it is possible to achieve melanopsin mutants that resist red light-induced activation but are activated by blue light and display properties indicating preserved bistability. Using the A333T mutant, we show that the blue light-induced subcellular melanopsin activation triggers localized PIP3 generation and macrophage migration, which we imaged using red light, demonstrating the optogenetic utility of minimally engineered melanopsins.
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Affiliation(s)
| | - Filippo Sacchetta
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | | | - Francesca Fanelli
- Department of Life Sciences, Dulbecco Telethon Institute, University of Modena and Reggio Emilia, Modena, I-41125, Italy
| | - Tomohiro Sugihara
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
| | - Mitsumasa Koyanagi
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
- The OMU Advanced Research Institute for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Senuri Piyawardana
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA
| | - Kiran Ghotra
- Department of Biology, Siena Heights University, Adrian, MI, 49221, USA
| | - Waruna Thotamune
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA
| | - Akihisa Terakita
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
- The OMU Advanced Research Institute for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Massimo Olivucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA.
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2
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Liu L, Huang B, Lu Y, Zhao Y, Tang X, Shi Y. Interactions between electromagnetic radiation and biological systems. iScience 2024; 27:109201. [PMID: 38433903 PMCID: PMC10906530 DOI: 10.1016/j.isci.2024.109201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
Even though the bioeffects of electromagnetic radiation (EMR) have been extensively investigated during the past several decades, our understandings of the bioeffects of EMR and the mechanisms of the interactions between the biological systems and the EMRs are still far from satisfactory. In this article, we introduce and summarize the consensus, controversy, limitations, and unsolved issues. The published works have investigated the EMR effects on different biological systems including humans, animals, cells, and biochemical reactions. Alternative methodologies also include dielectric spectroscopy, detection of bioelectromagnetic emissions, and theoretical predictions. In many studies, the thermal effects of the EMR are not properly controlled or considered. The frequency of the EMR investigated is limited to the commonly used bands, particularly the frequencies of the power line and the wireless communications; far fewer studies were performed for other EMR frequencies. In addition, the bioeffects of the complex EM environment were rarely discussed. In summary, our understanding of the bioeffects of the EMR is quite restrictive and further investigations are needed to answer the unsolved questions.
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Affiliation(s)
- Lingyu Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Huang
- Brain Function and Disease Laboratory, Department of Pharmacology, Shantou University Medical College, 22 Xin-Ling Road, Shantou 515041, China
| | - Yingxian Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yanyu Zhao
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Xiaping Tang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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3
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Huang Y, Li N, Yang C, Lin Y, Wen Y, Zheng L, Zhao C. Honeybee as a food nutrition analysis model of neural development and gut microbiota. Neurosci Biobehav Rev 2023; 153:105372. [PMID: 37652394 DOI: 10.1016/j.neubiorev.2023.105372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 07/13/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
Research on the relationships between the gut microbiota and the neurophysiology and behavior of animals has grown exponentially in just a few years. Insect behavior may be controlled by molecular mechanisms that are partially homologous to those in mammals, and swarming insects may be suitable as experiment models in these types of investigations. All core gut bacteria in honeybees can be cultivated in vitro. Certain gut microflora of bees can be genetically engineered or sterilized and colonized. The bee gut bacteria model is established more rapidly and has a higher flux than other sterile animal models. It may help elucidate the pathogenesis of intestinal diseases and identify effective molecular therapeutic targets against them. In the present review, we focused on the contributions of the honeybee model in learning cognition and microbiome research. We explored the relationship between honeybee behavior and neurodevelopment and the factors determining the mechanisms by which the gut microbiota affects the host. In particular, we concentrated on the correlation between gut microbiota and brain development. Finally, we examined strategies for the effective use of simple animal models in animal cognition and microbiome research.
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Affiliation(s)
- Yajun Huang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Na Li
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chengfeng Yang
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Yan Lin
- College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuxi Wen
- College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Department of Analytical and Food Chemistry, Faculty of Sciences, Universidade de Vigo, 32004 Ourense, Spain
| | - Lingjun Zheng
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Chao Zhao
- College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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4
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Wu A, Salom D, Hong JD, Tworak A, Watanabe K, Pardon E, Steyaert J, Kandori H, Katayama K, Kiser PD, Palczewski K. Structural basis for the allosteric modulation of rhodopsin by nanobody binding to its extracellular domain. Nat Commun 2023; 14:5209. [PMID: 37626045 PMCID: PMC10457330 DOI: 10.1038/s41467-023-40911-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Rhodopsin is a prototypical G protein-coupled receptor (GPCR) critical for vertebrate vision. Research on GPCR signaling states has been facilitated using llama-derived nanobodies (Nbs), some of which bind to the intracellular surface to allosterically modulate the receptor. Extracellularly binding allosteric nanobodies have also been investigated, but the structural basis for their activity has not been resolved to date. Here, we report a library of Nbs that bind to the extracellular surface of rhodopsin and allosterically modulate the thermodynamics of its activation process. Crystal structures of Nb2 in complex with native rhodopsin reveal a mechanism of allosteric modulation involving extracellular loop 2 and native glycans. Nb2 binding suppresses Schiff base deprotonation and hydrolysis and prevents intracellular outward movement of helices five and six - a universal activation event for GPCRs. Nb2 also mitigates protein misfolding in a disease-associated mutant rhodopsin. Our data show the power of nanobodies to modulate the photoactivation of rhodopsin and potentially serve as therapeutic agents for disease-associated rhodopsin misfolding.
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Affiliation(s)
- Arum Wu
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
| | - John D Hong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
| | - Kohei Watanabe
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466- 8555, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466- 8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466- 8555, Japan.
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan.
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA.
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA.
- Department of Clinical Pharmacy Practice, University of California, Irvine, CA, USA.
- Research Service, VA Long Beach Healthcare System, Long Beach, CA, USA.
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA.
- Department of Chemistry, University of California, Irvine, CA, 92697, USA.
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA.
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, 92697, USA.
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5
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Ellis EM, Paniagua AE, Scalabrino ML, Thapa M, Rathinavelu J, Jiao Y, Williams DS, Field GD, Fain GL, Sampath AP. Cones and cone pathways remain functional in advanced retinal degeneration. Curr Biol 2023; 33:1513-1522.e4. [PMID: 36977418 PMCID: PMC10133175 DOI: 10.1016/j.cub.2023.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/14/2022] [Accepted: 03/03/2023] [Indexed: 03/29/2023]
Abstract
Most defects causing retinal degeneration in retinitis pigmentosa (RP) are rod-specific mutations, but the subsequent degeneration of cones, which produces loss of daylight vision and high-acuity perception, is the most debilitating feature of the disease. To understand better why cones degenerate and how cone vision might be restored, we have made the first single-cell recordings of light responses from degenerating cones and retinal interneurons after most rods have died and cones have lost their outer-segment disk membranes and synaptic pedicles. We show that degenerating cones have functional cyclic-nucleotide-gated channels and can continue to give light responses, apparently produced by opsin localized either to small areas of organized membrane near the ciliary axoneme or distributed throughout the inner segment. Light responses of second-order horizontal and bipolar cells are less sensitive but otherwise resemble those of normal retina. Furthermore, retinal output as reflected in responses of ganglion cells is less sensitive but maintains spatiotemporal receptive fields at cone-mediated light levels. Together, these findings show that cones and their retinal pathways can remain functional even as degeneration is progressing, an encouraging result for future research aimed at enhancing the light sensitivity of residual cones to restore vision in patients with genetically inherited retinal degeneration.
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Affiliation(s)
- Erika M Ellis
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA
| | - Antonio E Paniagua
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA
| | - Miranda L Scalabrino
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA; Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mishek Thapa
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA; Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jay Rathinavelu
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yuekan Jiao
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA
| | - David S Williams
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA.
| | - Greg D Field
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA; Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Gordon L Fain
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA.
| | - Alapakkam P Sampath
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095-7000, USA.
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6
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Hofmann KP, Lamb TD. Rhodopsin, light-sensor of vision. Prog Retin Eye Res 2023; 93:101116. [PMID: 36273969 DOI: 10.1016/j.preteyeres.2022.101116] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022]
Abstract
The light sensor of vertebrate scotopic (low-light) vision, rhodopsin, is a G-protein-coupled receptor comprising a polypeptide chain with bound chromophore, 11-cis-retinal, that exhibits remarkable physicochemical properties. This photopigment is extremely stable in the dark, yet its chromophore isomerises upon photon absorption with 70% efficiency, enabling the activation of its G-protein, transducin, with high efficiency. Rhodopsin's photochemical and biochemical activities occur over very different time-scales: the energy of retinaldehyde's excited state is stored in <1 ps in retinal-protein interactions, but it takes milliseconds for the catalytically active state to form, and many tens of minutes for the resting state to be restored. In this review, we describe the properties of rhodopsin and its role in rod phototransduction. We first introduce rhodopsin's gross structural features, its evolution, and the basic mechanisms of its activation. We then discuss light absorption and spectral sensitivity, photoreceptor electrical responses that result from the activity of individual rhodopsin molecules, and recovery of rhodopsin and the visual system from intense bleaching exposures. We then provide a detailed examination of rhodopsin's molecular structure and function, first in its dark state, and then in the active Meta states that govern its interactions with transducin, rhodopsin kinase and arrestin. While it is clear that rhodopsin's molecular properties are exquisitely honed for phototransduction, from starlight to dawn/dusk intensity levels, our understanding of how its molecular interactions determine the properties of scotopic vision remains incomplete. We describe potential future directions of research, and outline several major problems that remain to be solved.
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Affiliation(s)
- Klaus Peter Hofmann
- Institut für Medizinische Physik und Biophysik (CC2), Charité, and, Zentrum für Biophysik und Bioinformatik, Humboldt-Unversität zu Berlin, Berlin, 10117, Germany.
| | - Trevor D Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
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Kojima K, Sudo Y. Convergent evolution of animal and microbial rhodopsins. RSC Adv 2023; 13:5367-5381. [PMID: 36793294 PMCID: PMC9923458 DOI: 10.1039/d2ra07073a] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/05/2023] [Indexed: 02/15/2023] Open
Abstract
Rhodopsins, a family of photoreceptive membrane proteins, contain retinal as a chromophore and were firstly identified as reddish pigments from frog retina in 1876. Since then, rhodopsin-like proteins have been identified mainly from animal eyes. In 1971, a rhodopsin-like pigment was discovered from the archaeon Halobacterium salinarum and named bacteriorhodopsin. While it was believed that rhodopsin- and bacteriorhodopsin-like proteins were expressed only in animal eyes and archaea, respectively, before the 1990s, a variety of rhodopsin-like proteins (called animal rhodopsins or opsins) and bacteriorhodopsin-like proteins (called microbial rhodopsins) have been progressively identified from various tissues of animals and microorganisms, respectively. Here, we comprehensively introduce the research conducted on animal and microbial rhodopsins. Recent analysis has revealed that the two rhodopsin families have common molecular properties, such as the protein structure (i.e., 7-transmembrane structure), retinal structure (i.e., binding ability to cis- and trans-retinal), color sensitivity (i.e., UV- and visible-light sensitivities), and photoreaction (i.e., triggering structural changes by light and heat), more than what was expected at the early stages of rhodopsin research. Contrastingly, their molecular functions are distinctively different (e.g., G protein-coupled receptors and photoisomerases for animal rhodopsins and ion transporters and phototaxis sensors for microbial rhodopsins). Therefore, based on their similarities and dissimilarities, we propose that animal and microbial rhodopsins have convergently evolved from their distinctive origins as multi-colored retinal-binding membrane proteins whose activities are regulated by light and heat but independently evolved for different molecular and physiological functions in the cognate organism.
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Affiliation(s)
- Keiichi Kojima
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Japan
| | - Yuki Sudo
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Japan
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8
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Gulati S, Palczewski K. Structural view of G protein-coupled receptor signaling in the retinal rod outer segment. Trends Biochem Sci 2023; 48:172-186. [PMID: 36163145 PMCID: PMC9868064 DOI: 10.1016/j.tibs.2022.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 01/26/2023]
Abstract
Visual phototransduction is the most extensively studied G protein-coupled receptor (GPCR) signaling pathway because of its quantifiable stimulus, non-redundancy of genes, and immense importance in vision. We summarize recent discoveries that have advanced our understanding of rod outer segment (ROS) morphology and the pathological basis of retinal diseases. We have combined recently published cryo-electron tomography (cryo-ET) data on the ROS with structural knowledge on individual proteins to define the precise spatial limitations under which phototransduction occurs. Although hypothetical, the reconstruction of the rod phototransduction system highlights the potential roles of phosphodiesterase 6 (PDE6) and guanylate cyclases (GCs) in maintaining the spacing between ROS discs, suggesting a plausible mechanism by which intrinsic optical signals are generated in the retina.
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Affiliation(s)
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, Center for Translational Vision Research, Department of Physiology and Biophysics, Department of Chemistry, Molecular Biology, and Biochemistry, University of California Irvine, 850 Health Sciences Road, Irvine, CA 92697-4375, USA.
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9
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Hagen JFD, Roberts NS, Johnston RJ. The evolutionary history and spectral tuning of vertebrate visual opsins. Dev Biol 2023; 493:40-66. [PMID: 36370769 PMCID: PMC9729497 DOI: 10.1016/j.ydbio.2022.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Many animals depend on the sense of vision for survival. In eumetazoans, vision requires specialized, light-sensitive cells called photoreceptors. Light reaches the photoreceptors and triggers the excitation of light-detecting proteins called opsins. Here, we describe the story of visual opsin evolution from the ancestral bilaterian to the extant vertebrate lineages. We explain the mechanisms determining color vision of extant vertebrates, focusing on opsin gene losses, duplications, and the expression regulation of vertebrate opsins. We describe the sequence variation both within and between species that has tweaked the sensitivities of opsin proteins towards different wavelengths of light. We provide an extensive resource of wavelength sensitivities and mutations that have diverged light sensitivity in many vertebrate species and predict how these mutations were accumulated in each lineage based on parsimony. We suggest possible natural and sexual selection mechanisms underlying these spectral differences. Understanding how molecular changes allow for functional adaptation of animals to different environments is a major goal in the field, and therefore identifying mutations affecting vision and their relationship to photic selection pressures is imperative. The goal of this review is to provide a comprehensive overview of our current understanding of opsin evolution in vertebrates.
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Affiliation(s)
- Joanna F D Hagen
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Natalie S Roberts
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA.
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10
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Abstract
Although G-protein–coupled receptors (GPCRs) control vast physiological pathways, their activation remains chemically and physically enigmatic. Our osmotic stress studies of the visual receptor rhodopsin have redefined the standard model of GPCR signaling by revealing the essential role of bulk water. We show results consistent with a large number of water molecules flooding the rhodopsin interior during activation to stabilize the effector binding conformation. These results suggest a model of GPCR activation in which the receptor becomes solvent-swollen upon formation of the active state. We thus demonstrate the mechanism whereby water acts as a powerful allosteric modulator of a pharmacologically important membrane protein family. The Rhodopsin family of G-protein–coupled receptors (GPCRs) comprises the targets of nearly a third of all pharmaceuticals. Despite structural water present in GPCR X-ray structures, the physiological relevance of these solvent molecules to rhodopsin signaling remains unknown. Here, we show experimental results consistent with the idea that rhodopsin activation in lipid membranes is coupled to bulk water movements into the protein. To quantify hydration changes, we measured reversible shifting of the metarhodopsin equilibrium due to osmotic stress using an extensive series of polyethylene glycol (PEG) osmolytes. We discovered clear evidence that light activation entails a large influx of bulk water (∼80–100 molecules) into the protein, giving insight into GPCR activation mechanisms. Various size polymer osmolytes directly control rhodopsin activation, in which large solutes are excluded from rhodopsin and dehydrate the protein, favoring the inactive state. In contrast, small osmolytes initially forward shift the activation equilibrium until a quantifiable saturation point is reached, similar to gain-of-function protein mutations. For the limit of increasing osmolyte size, a universal response of rhodopsin to osmotic stress is observed, suggesting it adopts a dynamic, hydrated sponge-like state upon photoactivation. Our results demand a rethinking of the role of water dynamics in modulating various intermediates in the GPCR energy landscape. We propose that besides bound water, an influx of bulk water plays a necessary role in establishing the active GPCR conformation that mediates signaling.
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11
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Felline A, Schiroli D, Comitato A, Marigo V, Fanelli F. Structure network-based landscape of rhodopsin misfolding by mutations and algorithmic prediction of small chaperone action. Comput Struct Biotechnol J 2021; 19:6020-6038. [PMID: 34849206 PMCID: PMC8605067 DOI: 10.1016/j.csbj.2021.10.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/09/2021] [Accepted: 10/31/2021] [Indexed: 11/28/2022] Open
Abstract
Failure of a protein to achieve its functional structural state and normal cellular location contributes to the etiology and pathology of heritable human conformational diseases. The autosomal dominant form of retinitis pigmentosa (adRP) is an incurable blindness largely linked to mutations of the membrane protein rod opsin. While the mechanisms underlying the noxious effects of the mutated protein are not completely understood, a common feature is the functional protein conformational loss. Here, the wild type and 39 adRP rod opsin mutants were subjected to mechanical unfolding simulations coupled to the graph theory-based protein structure network analysis. A robust computational model was inferred and in vitro validated in its ability to predict endoplasmic reticulum retention of adRP mutants, a feature linked to the mutation-caused misfolding. The structure-based approach could also infer the structural determinants of small chaperone action on misfolded protein mutants with therapeutic implications. The approach is exportable to conformational diseases linked to missense mutations in any membrane protein.
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Affiliation(s)
- Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Davide Schiroli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy.,Center for Neuroscience and Neurotechnology, Italy
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy.,Center for Neuroscience and Neurotechnology, Italy
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12
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Vöcking O, Leclère L, Hausen H. The rhodopsin-retinochrome system for retinal re-isomerization predates the origin of cephalopod eyes. BMC Ecol Evol 2021; 21:215. [PMID: 34844573 PMCID: PMC8628405 DOI: 10.1186/s12862-021-01939-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 11/11/2021] [Indexed: 11/10/2022] Open
Abstract
Background The process of photoreception in most animals depends on the light induced isomerization of the chromophore retinal, bound to rhodopsin. To re-use retinal, the all-trans-retinal form needs to be re-isomerized to 11-cis-retinal, which can be achieved in different ways. In vertebrates, this mostly includes a stepwise enzymatic process called the visual cycle. The best studied re-isomerization system in protostomes is the rhodopsin-retinochrome system of cephalopods, which consists of rhodopsin, the photoisomerase retinochrome and the protein RALBP functioning as shuttle for retinal. In this study we investigate the expression of the rhodopsin-retinochrome system and functional components of the vertebrate visual cycle in a polyplacophoran mollusk, Leptochiton asellus, and examine the phylogenetic distribution of the individual components in other protostome animals. Results Tree-based orthology assignments revealed that orthologs of the cephalopod retinochrome and RALBP are present in mollusks outside of cephalopods. By mining our dataset for vertebrate visual cycle components, we also found orthologs of the retinoid binding protein RLBP1, in polyplacophoran mollusks, cephalopods and a phoronid. In situ hybridization and antibody staining revealed that L. asellus retinochrome is co-expressed in the larval chiton photoreceptor cells (PRCs) with the visual rhodopsin, RALBP and RLBP1. In addition, multiple retinal dehydrogenases are expressed in the PRCs, which might also contribute to the rhodopsin-retinochrome system. Conclusions We conclude that the rhodopsin-retinochrome system is a common feature of mollusk PRCs and predates the origin of cephalopod eyes. Our results show that this system has to be extended by adding further components, which surprisingly, are shared with vertebrates. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01939-x.
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Affiliation(s)
- Oliver Vöcking
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008, Bergen, Norway. .,Department of Biology, University of Kentucky, Thomas Hunt Morgan Building, 675 Rose Street, Lexington, KY, 40508, USA.
| | - Lucas Leclère
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Villefranche-sur-Mer, France
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008, Bergen, Norway
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13
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Picarazzi F, Manetti F, Marigo V, Mori M. Conformational insights into the C-terminal mutations of human rhodopsin in retinitispigmentosa. J Mol Graph Model 2021; 110:108076. [PMID: 34798368 DOI: 10.1016/j.jmgm.2021.108076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
Rhodopsin is a light-sensitive transmembrane receptor involved in the visual transduction cascade. Among the several rhodopsin mutations related to retinitis pigmentosa (RP), those affecting the C-terminal VAPA-COOH motif that is implicated in rhodopsin trafficking from the Golgi to the rod outer segment are notably associated with more aggressive RP forms. However, molecular reasons for defective rhodopsin signaling due to VAPA-COOH mutations, which might include steric hindrance, physicochemical features and structural determinants, are yet unknown, thus limiting further drug design approaches. In this work, clinically relevant rhodopsin mutations at the P347 site within the VAPA-COOH motif were investigated by molecular dynamics (MD) simulations and compared to the wild-type (WT) system. In agreement with experimental evidence, conformational fluctuations of the intrinsically disordered C-terminal tail of WT and mutant rhodopsin were found not to affect the overall structure of the transmembrane domain, including binding to the retinal cofactor. The WT VAPA-COOH motif adopts a unique conformation that is not found in pathological mutants, suggesting that structural features could better explain the pathogenicity of P347 rhodopsin mutants than physicochemical or steric determinants. These results were confirmed by MD simulations in both membrane-embedded full-length opsin and membrane-free C-terminal deca-peptides, these latter becoming very useful and small-size model systems for further investigations of rhodopsin C-terminal mutations. Structural details elucidated in this work might facilitate the understanding of the pathological mechanisms of this class of rhodopsin mutants, which will be instrumental to the development of new therapeutic strategies.
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Affiliation(s)
- Francesca Picarazzi
- Department of Biotechnology, Chemistry and Pharmacy, "Department of Excellence 2018-2022", University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Fabrizio Manetti
- Department of Biotechnology, Chemistry and Pharmacy, "Department of Excellence 2018-2022", University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi, 287, 41125 Modena, Italy
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, "Department of Excellence 2018-2022", University of Siena, Via Aldo Moro 2, 53100 Siena, Italy.
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14
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Manzini I, Schild D, Di Natale C. Principles of odor coding in vertebrates and artificial chemosensory systems. Physiol Rev 2021; 102:61-154. [PMID: 34254835 DOI: 10.1152/physrev.00036.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biological olfactory system is the sensory system responsible for the detection of the chemical composition of the environment. Several attempts to mimic biological olfactory systems have led to various artificial olfactory systems using different technical approaches. Here we provide a parallel description of biological olfactory systems and their technical counterparts. We start with a presentation of the input to the systems, the stimuli, and treat the interface between the external world and the environment where receptor neurons or artificial chemosensors reside. We then delineate the functions of receptor neurons and chemosensors as well as their overall I-O relationships. Up to this point, our account of the systems goes along similar lines. The next processing steps differ considerably: while in biology the processing step following the receptor neurons is the "integration" and "processing" of receptor neuron outputs in the olfactory bulb, this step has various realizations in electronic noses. For a long period of time, the signal processing stages beyond the olfactory bulb, i.e., the higher olfactory centers were little studied. Only recently there has been a marked growth of studies tackling the information processing in these centers. In electronic noses, a third stage of processing has virtually never been considered. In this review, we provide an up-to-date overview of the current knowledge of both fields and, for the first time, attempt to tie them together. We hope it will be a breeding ground for better information, communication, and data exchange between very related but so far little connected fields.
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Affiliation(s)
- Ivan Manzini
- Animal Physiology and Molecular Biomedicine, Justus-Liebig-University Gießen, Gießen, Germany
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University Medical Center, University of Göttingen, Göttingen, Germany
| | - Corrado Di Natale
- Department of Electronic Engineering, University of Rome Tor Vergata, Rome, Italy
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15
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Dong X, Liang Q, Li J, Feng P. Positive selection drives the evolution of a primate bitter taste receptor gene. Ecol Evol 2021; 11:5459-5467. [PMID: 34026020 PMCID: PMC8131804 DOI: 10.1002/ece3.7440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/20/2021] [Accepted: 02/24/2021] [Indexed: 12/22/2022] Open
Abstract
Bitter taste perception is important in food choice of animals, and it is mediated by bitter taste receptor (T2R) containing three regions: extracellular regions (ECs), transmembrane regions (TMs), and intracellular regions (ICs). It is hypothesized that ECs, TMs, and ICs are under different selective pressures, with ECs being unstable while TMs and ICs being constrained. To test this hypothesis, we examined the selective pressures on one of the bitter taste receptor genes-T2R1 and its different areas from 35 primates and found that T2R1 was under neutral evolution but with some positively selected sites in it. Further analyses suggested that TMs, ICs, and the concatenated transmembrane region TM1237 were under purifying selection; in contrast, extracellular regions, the first and second extracellular loop (EL1, EL2), were subject to positive selection with several positively selected sites in them. Therefore, this study supported the above-mentioned hypothesis. The reason why EL1 and EL2 of T2R1 have positively selected sites is probably due to their participation in forming the cap-like structure involved in ligand binding. Positive selection acts as a driving force of the T2R1 functional differentiation and confers the ability to discern various bitter substances for primates, which could help them to adapt to the changing environment during the evolutionary course.
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Affiliation(s)
- Xiaoyan Dong
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University)Ministry of EducationGuilinChina
- Guangxi Key Laboratory of Rare and Endangered Animal EcologyGuangxi Normal UniversityGuilinChina
| | - Qiufang Liang
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University)Ministry of EducationGuilinChina
- Guangxi Key Laboratory of Rare and Endangered Animal EcologyGuangxi Normal UniversityGuilinChina
| | - Jiaping Li
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University)Ministry of EducationGuilinChina
- Guangxi Key Laboratory of Rare and Endangered Animal EcologyGuangxi Normal UniversityGuilinChina
| | - Ping Feng
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University)Ministry of EducationGuilinChina
- Guangxi Key Laboratory of Rare and Endangered Animal EcologyGuangxi Normal UniversityGuilinChina
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16
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Aguilera-Durán G, Romo-Mancillas A. Behavior of Chemokine Receptor 6 (CXCR6) in Complex with CXCL16 Soluble form Chemokine by Molecular Dynamic Simulations: General Protein‒Ligand Interaction Model and 3D-QSAR Studies of Synthetic Antagonists. Life (Basel) 2021; 11:life11040346. [PMID: 33920834 PMCID: PMC8071165 DOI: 10.3390/life11040346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 01/19/2023] Open
Abstract
The CXCR6‒CXCL16 axis is involved in several pathological processes, and its overexpression has been detected in different types of cancer, such as prostate, breast, ovary, and lung cancer, along with schwannomas, in which it promotes invasion and metastasis. Moreover, this axis is involved in atherosclerosis, type 1 diabetes, primary immune thrombocytopenia, vitiligo, and other autoimmune diseases, in which it is responsible for the infiltration of different immune system cells. The 3D structure of CXCR6 and CXCL16 has not been experimentally resolved; therefore, homology modeling and molecular dynamics simulations could be useful for the study of this signaling axis. In this work, a homology model of CXCR6 and a soluble form of CXCL16 (CXCR6‒CXCL16s) are reported to study the interactions between CXCR6 and CXCL16s through coarse-grained molecular dynamics (CG-MD) simulations. CG-MD simulations showed the two activation steps of CXCR6 through a decrease in the distance between the chemokine and the transmembrane region (TM) of CXCR6 and transmembrane rotational changes and polar interactions between transmembrane segments. The polar interactions between TM3, TM5, and TM6 are fundamental to functional conformation and the meta-active state of CXCR6. The interactions between D77-R280 and T243-TM7 could be related to the functional conformation of CXCR6; alternatively, the interaction between Q195-Q244 and N248 could be related to an inactive state due to the loss of this interaction, and an arginine cage broken in the presence of CXCL16s allows the meta-active state of CXCR6. A general protein‒ligand interaction supports the relevance of TM3‒TM5‒TM6 interactions, presenting three relevant pharmacophoric features: HAc (H-bond acceptor), HDn (H-bond donator), and Hph (hydrophobic), distributed around the space between extracellular loops (ECLs) and TMs. The HDn feature is close to TM3 and TM6; likewise, the HAc and Hph features are close to ECL1 and ECL2 and could block the rotation and interactions between TM3‒TM6 and the interactions of CXCL16s with the ECLs. Tridimensional quantitative structure-activity relationships (3D-QSAR) models show that the positive steric (VdW) and electrostatic fields coincide with the steric and positive electrostatic region of the exo-azabicyclo[3.3.1]nonane scaffold in the best pIC50 ligands. This substructure is close to the E274 residue and therefore relevant to the activity of CXCR6. These data could help with the design of new molecules that inhibit chemokine binding or antagonize the receptor based on the activation mechanism of CXCR6 and provoke a decrease in chemotaxis caused by the CXCR6‒CXCL16 axis.
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Affiliation(s)
- Giovanny Aguilera-Durán
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Querétaro 76010, Mexico;
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico
| | - Antonio Romo-Mancillas
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico
- Correspondence:
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17
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Fanelli F, Felline A, Marigo V. Structural aspects of rod opsin and their implication in genetic diseases. Pflugers Arch 2021; 473:1339-1359. [PMID: 33728518 DOI: 10.1007/s00424-021-02546-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
Vision in dim-light conditions is triggered by photoactivation of rhodopsin, the visual pigment of rod photoreceptor cells. Rhodopsin is made of a protein, the G protein coupled receptor (GPCR) opsin, and the chromophore 11-cis-retinal. Vertebrate rod opsin is the GPCR best characterized at the atomic level of detail. Since the release of the first crystal structure 20 years ago, a huge number of structures have been released that, in combination with valuable spectroscopic determinations, unveiled most aspects of the photobleaching process. A number of spontaneous mutations of rod opsin have been found linked to vision-impairing diseases like autosomal dominant or autosomal recessive retinitis pigmentosa (adRP or arRP, respectively) and autosomal congenital stationary night blindness (adCSNB). While adCSNB is mainly caused by constitutive activation of rod opsin, RP shows more variegate determinants affecting different aspects of rod opsin function. The vast majority of missense rod opsin mutations affects folding and trafficking and is linked to adRP, an incurable disease that awaits light on its molecular structure determinants. This review article summarizes all major structural information available on vertebrate rod opsin conformational states and the insights gained so far into the structural determinants of adCSNB and adRP linked to rod opsin mutations. Strategies to design small chaperones with therapeutic potential for selected adRP rod opsin mutants will be discussed as well.
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Affiliation(s)
- Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy. .,Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy
| | - Valeria Marigo
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.,Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125, Modena, Italy
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18
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Aguilera-Durán G, Romo-Mancillas A. Computational Study of C-X-C Chemokine Receptor (CXCR)3 Binding with Its Natural Agonists Chemokine (C-X-C Motif) Ligand (CXCL)9, 10 and 11 and with Synthetic Antagonists: Insights of Receptor Activation towards Drug Design for Vitiligo. Molecules 2020; 25:E4413. [PMID: 32992956 PMCID: PMC7582348 DOI: 10.3390/molecules25194413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/31/2022] Open
Abstract
Vitiligo is a hypopigmentary skin pathology resulting from the death of melanocytes due to the activity of CD8+ cytotoxic lymphocytes and overexpression of chemokines. These include CXCL9, CXCL10, and CXCL11 and its receptor CXCR3, both in peripheral cells of the immune system and in the skin of patients diagnosed with vitiligo. The three-dimensional structure of CXCR3 and CXCL9 has not been reported experimentally; thus, homology modeling and molecular dynamics could be useful for the study of this chemotaxis-promoter axis. In this work, a homology model of CXCR3 and CXCL9 and the structure of the CXCR3/Gαi/0βγ complex with post-translational modifications of CXCR3 are reported for the study of the interaction of chemokines with CXCR3 through all-atom (AA-MD) and coarse-grained molecular dynamics (CG-MD) simulations. AA-MD and CG-MD simulations showed the first activation step of the CXCR3 receptor with all chemokines and the second activation step in the CXCR3-CXCL10 complex through a decrease in the distance between the chemokine and the transmembrane region of CXCR3 and the separation of the βγ complex from the α subunit in the G-protein. Additionally, a general protein-ligand interaction model was calculated, based on known antagonists binding to CXCR3. These results contribute to understanding the activation mechanism of CXCR3 and the design of new molecules that inhibit chemokine binding or antagonize the receptor, provoking a decrease of chemotaxis caused by the CXCR3/chemokines axis.
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Affiliation(s)
- Giovanny Aguilera-Durán
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Querétaro 76010, Mexico;
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico
| | - Antonio Romo-Mancillas
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico
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19
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Li W. Residue-Residue Mutual Work Analysis of Retinal-Opsin Interaction in Rhodopsin: Implications for Protein-Ligand Binding. J Chem Theory Comput 2020; 16:1834-1842. [PMID: 31972074 DOI: 10.1021/acs.jctc.9b01035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Energetic contributions at the single-residue level for retinal-opsin interactions in rhodopsin were studied by combining molecular dynamics simulations, transition path sampling, and a newly developed energy decomposition approach. The virtual work at an infinitesimal time interval was decomposed into the work components on one residue due to its interaction with another residue, which were then averaged over the transition path ensemble along a proposed reaction coordinate. Such residue-residue mutual work analysis on 62 residues within the active center of rhodopsin resulted in a very sparse interaction matrix, which is generally not symmetric but antisymmetric to some extent. Fourteen residues were identified to be major players in retinal relaxation along a plausible pathway from bathorhodopsin to the blue-shifted intermediate, which is in good agreement with an existing NMR study. Based on the matrix of mutual work, a comprehensive network was constructed to provide detailed insights into the chromophore-protein interaction from a viewpoint of energy flow.
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Affiliation(s)
- Wenjin Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
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20
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Zhou Q, Yang D, Wu M, Guo Y, Guo W, Zhong L, Cai X, Dai A, Jang W, Shakhnovich EI, Liu ZJ, Stevens RC, Lambert NA, Babu MM, Wang MW, Zhao S. Common activation mechanism of class A GPCRs. eLife 2019; 8:e50279. [PMID: 31855179 PMCID: PMC6954041 DOI: 10.7554/elife.50279] [Citation(s) in RCA: 297] [Impact Index Per Article: 59.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
Class A G-protein-coupled receptors (GPCRs) influence virtually every aspect of human physiology. Understanding receptor activation mechanism is critical for discovering novel therapeutics since about one-third of all marketed drugs target members of this family. GPCR activation is an allosteric process that couples agonist binding to G-protein recruitment, with the hallmark outward movement of transmembrane helix 6 (TM6). However, what leads to TM6 movement and the key residue level changes of this movement remain less well understood. Here, we report a framework to quantify conformational changes. By analyzing the conformational changes in 234 structures from 45 class A GPCRs, we discovered a common GPCR activation pathway comprising of 34 residue pairs and 35 residues. The pathway unifies previous findings into a common activation mechanism and strings together the scattered key motifs such as CWxP, DRY, Na+ pocket, NPxxY and PIF, thereby directly linking the bottom of ligand-binding pocket with G-protein coupling region. Site-directed mutagenesis experiments support this proposition and reveal that rational mutations of residues in this pathway can be used to obtain receptors that are constitutively active or inactive. The common activation pathway provides the mechanistic interpretation of constitutively activating, inactivating and disease mutations. As a module responsible for activation, the common pathway allows for decoupling of the evolution of the ligand binding site and G-protein-binding region. Such an architecture might have facilitated GPCRs to emerge as a highly successful family of proteins for signal transduction in nature.
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Affiliation(s)
- Qingtong Zhou
- iHuman InstituteShanghaiTech UniversityShanghaiChina
| | - Dehua Yang
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Meng Wu
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Yu Guo
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Wanjing Guo
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Li Zhong
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Xiaoqing Cai
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Antao Dai
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of GeorgiaAugusta UniversityAugustaUnited States
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeUnited States
| | - Zhi-Jie Liu
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Raymond C Stevens
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of GeorgiaAugusta UniversityAugustaUnited States
| | - M Madan Babu
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Ming-Wei Wang
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
- School of PharmacyFudan UniversityShanghaiChina
| | - Suwen Zhao
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
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21
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Wang D, Qin Y, Zhang S, Wang L, Yang X, Zhong D. Elucidating the Molecular Mechanism of Ultrafast Pfr-State Photoisomerization in Bathy Bacteriophytochrome PaBphP. J Phys Chem Lett 2019; 10:6197-6201. [PMID: 31577445 PMCID: PMC7268903 DOI: 10.1021/acs.jpclett.9b02446] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bacteriophytochromes are photoreceptors that regulate various physiological processes induced by photoisomerization in a linear tetrapyrrole chromophore upon red/far-red light absorption. Here, we investigate the photoinduced Pfr-state isomerization mechanism of a bathy bacteriophytochrome from Pseudomonas aeruginosa combining femtosecond-resolved fluorescence and absorption methods. We observed initial coherent oscillation motions in the first 1 ps with low-frequency modes below 60 cm-1, then a bifurcation of the wavepacket with the distinct excited-state lifetimes in a few picoseconds, and finally chromophore-protein coupled ground-state conformational evolution on nanosecond time scales. Together with systematic mutational studies, we revealed the critical roles of hydrogen bonds in tuning the photoisomerization dynamics. These results provide a clear molecular picture of the Pfr-state photoisomerization, a mechanism likely applicable to the other phytochromes.
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Affiliation(s)
- Dihao Wang
- Department of Physics, Department of Chemistry and Biochemistry, Programs of Biophysics, Chemical
Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Yangzhong Qin
- Department of Physics, Department of Chemistry and Biochemistry, Programs of Biophysics, Chemical
Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Sheng Zhang
- Department of Physics, Department of Chemistry and Biochemistry, Programs of Biophysics, Chemical
Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Lijuan Wang
- Department of Physics, Department of Chemistry and Biochemistry, Programs of Biophysics, Chemical
Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Xiaojing Yang
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, United States
| | - Dongping Zhong
- Department of Physics, Department of Chemistry and Biochemistry, Programs of Biophysics, Chemical
Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
- Corresponding Author
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22
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Shalaeva DN, Cherepanov DA, Galperin MY, Vriend G, Mulkidjanian AY. G protein-coupled receptors of class A harness the energy of membrane potential to increase their sensitivity and selectivity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183051. [PMID: 31449800 DOI: 10.1016/j.bbamem.2019.183051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/28/2019] [Accepted: 08/21/2019] [Indexed: 12/31/2022]
Abstract
The human genome contains about 700 genes of G protein-coupled receptors (GPCRs) of class A; these seven-helical membrane proteins are the targets of almost half of all known drugs. In the middle of the helix bundle, crystal structures reveal a highly conserved sodium-binding site, which is connected with the extracellular side by a water-filled tunnel. This binding site contains a sodium ion in those GPCRs that are crystallized in their inactive conformations but does not in those GPCRs that are trapped in agonist-bound active conformations. The escape route of the sodium ion upon the inactive-to-active transition and its very direction have until now remained obscure. Here, by modeling the available experimental data, we show that the sodium gradient over the cell membrane increases the sensitivity of GPCRs if their activation is thermodynamically coupled to the sodium ion translocation into the cytoplasm but decreases it if the sodium ion retreats into the extracellular space upon receptor activation. The model quantitatively describes the available data on both activation and suppression of distinct GPCRs by membrane voltage. The model also predicts selective amplification of the signal from (endogenous) agonists if only they, but not their (partial) analogs, induce sodium translocation. Comparative structure and sequence analyses of sodium-binding GPCRs indicate a key role for the conserved leucine residue in the second transmembrane helix (Leu2.46) in coupling sodium translocation to receptor activation. Hence, class A GPCRs appear to harness the energy of the transmembrane sodium potential to increase their sensitivity and selectivity.
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Affiliation(s)
- Daria N Shalaeva
- School of Physics, Osnabrueck University, 49069 Osnabrück, Germany; A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Dmitry A Cherepanov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia; N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Russia.
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| | - Gert Vriend
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Centre, 6525 HP Nijmegen, the Netherlands.
| | - Armen Y Mulkidjanian
- School of Physics, Osnabrueck University, 49069 Osnabrück, Germany; A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia; School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119991, Russia.
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23
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A light in the dark: state of the art and perspectives in optogenetics and optopharmacology for restoring vision. Future Med Chem 2019; 11:463-487. [DOI: 10.4155/fmc-2018-0315] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the last decade, innovative therapeutic strategies against inherited retinal degenerations (IRDs) have emerged. In particular, chemical- and opto-genetics approaches or a combination of them have been identified for modulating neuronal/optical activity in order to restore vision in blinding diseases. The ‘chemical-genetics approach’ (optopharmacology) uses small molecules (exogenous photoswitches) for restoring light sensitivity by activating ion channels. The ‘opto-genetics approach’ employs light-activated photosensitive proteins (exogenous opsins), introduced by viral vectors in injured tissues, to restore light response. These approaches offer control of neuronal activities with spatial precision and limited invasiveness, although with some drawbacks. Currently, a combined therapeutic strategy (optogenetic pharmacology) is emerging. This review describes the state of the art and provides an overview of the future perspectives in vision restoration.
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24
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Rodgers J, Peirson SN, Hughes S, Hankins MW. Functional characterisation of naturally occurring mutations in human melanopsin. Cell Mol Life Sci 2018; 75:3609-3624. [PMID: 29700553 PMCID: PMC6133154 DOI: 10.1007/s00018-018-2813-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/06/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
Melanopsin is a blue light-sensitive opsin photopigment involved in a range of non-image forming behaviours, including circadian photoentrainment and the pupil light response. Many naturally occurring genetic variants exist within the human melanopsin gene (OPN4), yet it remains unclear how these variants affect melanopsin protein function and downstream physiological responses to light. Here, we have used bioinformatic analysis and in vitro expression systems to determine the functional phenotypes of missense human OPN4 variants. From 1242 human OPN4 variants collated in the NCBI Short Genetic Variation database (dbSNP), we identified 96 that lead to non-synonymous amino acid substitutions. These 96 missense mutations were screened using sequence alignment and comparative approaches to select 16 potentially deleterious variants for functional characterisation using calcium imaging of melanopsin-driven light responses in HEK293T cells. We identify several previously uncharacterised OPN4 mutations with altered functional properties, including attenuated or abolished light responses, as well as variants demonstrating abnormal response kinetics. These data provide valuable insight into the structure-function relationships of human melanopsin, including several key functional residues of the melanopsin protein. The identification of melanopsin variants with significantly altered function may serve to detect individuals with disrupted melanopsin-based light perception, and potentially highlight those at increased risk of sleep disturbance, circadian dysfunction, and visual abnormalities.
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Affiliation(s)
- Jessica Rodgers
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK.
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK.
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25
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Abstract
The first stage in biological signaling is based on changes in the functional state of a receptor protein triggered by interaction of the receptor with its ligand(s). The light-triggered nature of photoreceptors allows studies on the mechanism of such changes in receptor proteins using a wide range of biophysical methods and with superb time resolution. Here, we critically evaluate current understanding of proton and electron transfer in photosensory proteins and their involvement both in primary photochemistry and subsequent processes that lead to the formation of the signaling state. An insight emerging from multiple families of photoreceptors is that ultrafast primary photochemistry is followed by slower proton transfer steps that contribute to triggering large protein conformational changes during signaling state formation. We discuss themes and principles for light sensing shared by the six photoreceptor families: rhodopsins, phytochromes, photoactive yellow proteins, light-oxygen-voltage proteins, blue-light sensors using flavin, and cryptochromes.
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Affiliation(s)
- Tilman Kottke
- Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Aihua Xie
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | - Delmar S. Larsen
- Department of Chemistry, University of California, Davis, California 95616, USA
| | - Wouter D. Hoff
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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26
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Removal of the blue component of light significantly decreases retinal damage after high intensity exposure. PLoS One 2018; 13:e0194218. [PMID: 29543853 PMCID: PMC5854379 DOI: 10.1371/journal.pone.0194218] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 02/27/2018] [Indexed: 12/14/2022] Open
Abstract
Light causes damage to the retina (phototoxicity) and decreases photoreceptor responses to light. The most harmful component of visible light is the blue wavelength (400–500 nm). Different filters have been tested, but so far all of them allow passing a lot of this wavelength (70%). The aim of this work has been to prove that a filter that removes 94% of the blue component may protect the function and morphology of the retina significantly. Three experimental groups were designed. The first group was unexposed to light, the second one was exposed and the third one was exposed and protected by a blue-blocking filter. Light damage was induced in young albino mice (p30) by exposing them to white light of high intensity (5,000 lux) continuously for 7 days. Short wavelength light filters were used for light protection. The blue component was removed (94%) from the light source by our filter. Electroretinographical recordings were performed before and after light damage. Changes in retinal structure were studied using immunohistochemistry, and TUNEL labeling. Also, cells in the outer nuclear layer were counted and compared among the three different groups. Functional visual responses were significantly more conserved in protected animals (with the blue-blocking filter) than in unprotected animals. Also, retinal structure was better kept and photoreceptor survival was greater in protected animals, these differences were significant in central areas of the retina. Still, functional and morphological responses were significantly lower in protected than in unexposed groups. In conclusion, this blue-blocking filter decreases significantly photoreceptor damage after exposure to high intensity light. Actually, our eyes are exposed for a very long time to high levels of blue light (screens, artificial light LED, neons…). The potential damage caused by blue light can be palliated.
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27
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Plazinska A, Plazinski W, Luchowski R, Wnorowski A, Grudzinski W, Gruszecki WI. Ligand-induced action of the W286 6.48 rotamer toggle switch in the β 2-adrenergic receptor. Phys Chem Chem Phys 2017; 20:581-594. [PMID: 29226293 DOI: 10.1039/c7cp04808d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studies focused on GPCRs, particularly on the β2-adrenergic receptor (β2-AR), have demonstrated the relationship between ligand structure, receptor conformational changes and the corresponding pharmacological outcomes. Herein, we studied the molecular details of the rotameric flip of the W2866.48 sidechain, i.e. a presumed action switch that has not been reported in native β2-AR thus far. It is believed that although both the 'active' and 'inactive' conformers of β2-AR exhibit similar conformations of this switch, it may still play a substantial role in the ligand-induced activation of the receptor. By using both experimental methods (time-resolved fluorescence spectroscopy) and molecular modeling techniques (enhanced-sampling molecular dynamics), we characterized the conformational rearrangements of W2866.48 in relation to the type of ligand present in the binding cavity and to the conformation of the receptor ('active' vs. 'inactive' β2-AR). We found that the conformational behaviour of W2866.48 is correlated with the pharmacological character of the ligand present in the binding cavity but not with the instantaneous conformation of the receptor. Namely, agonists promote the W2866.48 conformations that facilitate the increase of the solvation within the inner receptor channel. In contrast, antagonists and inverse agonists act toward the decrease of the solvation in the inner channel. This creates an opportunity for using computational methodologies in determining the pharmacological properties of various ligands. The combination of the time-resolved fluorescence spectroscopy technique with the enhanced-sampling molecular dynamics simulations is shown to be a powerful tool for studying the ligand-induced conformational rearrangements in GPCRs.
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Affiliation(s)
- Anita Plazinska
- Department of Biopharmacy, Faculty of Pharmacy, Medical University of Lublin, W. Chodzki Str., 4a, 20-093 Lublin, Poland.
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28
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Agrawal SA, Burgoyne T, Eblimit A, Bellingham J, Parfitt DA, Lane A, Nichols R, Asomugha C, Hayes MJ, Munro PM, Xu M, Wang K, Futter CE, Li Y, Chen R, Cheetham ME. REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. Hum Mol Genet 2017; 26:2667-2677. [PMID: 28475715 PMCID: PMC5808736 DOI: 10.1093/hmg/ddx149] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
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Affiliation(s)
- Smriti A. Agrawal
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aiden Eblimit
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Chinwe Asomugha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Matthew J. Hayes
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mingchu Xu
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yumei Li
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Rui Chen
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
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29
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Jastrzebska B, Comar WD, Kaliszewski MJ, Skinner KC, Torcasio MH, Esway AS, Jin H, Palczewski K, Smith AW. A G Protein-Coupled Receptor Dimerization Interface in Human Cone Opsins. Biochemistry 2017; 56:61-72. [PMID: 28045251 PMCID: PMC5274527 DOI: 10.1021/acs.biochem.6b00877] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
G protein-coupled receptors (GPCRs) detect a wide variety of physical and chemical signals and transmit that information across the cellular plasma membrane. Dimerization is a proposed modulator of GPCR signaling, but the structure and stability of class A GPCR dimerization have been difficult to establish. Here we investigated the dimerization affinity and binding interface of human cone opsins, which initiate and sustain daytime color vision. Using a time-resolved fluorescence approach, we found that human red cone opsin exhibits a strong propensity for dimerization, whereas the green and blue cone opsins do not. Through mutagenesis experiments, we identified a dimerization interface in the fifth transmembrane helix of human red cone opsin involving amino acids I230, A233, and M236. Insights into this dimerization interface of red cone opsin should aid ongoing investigations of the structure and function of GPCR quaternary interactions in cell signaling. Finally, we demonstrated that the same residues needed for dimerization are also partially responsible for the spectral tuning of red cone opsin. This last observation has the potential to open up new lines of inquiry regarding the functional role of dimerization for red cone opsin.
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Affiliation(s)
- Beata Jastrzebska
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
| | - William D. Comar
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
| | - Megan J. Kaliszewski
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
| | - Kevin C. Skinner
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
| | - Morgan H. Torcasio
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
| | - Anthony S. Esway
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
| | - Hui Jin
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Adam W. Smith
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, Ohio 44325, United States
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30
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Abstract
Preparation and storage of functional membrane proteins such as G-protein-coupled receptors (GPCRs) are crucial to the processes of drug delivery and discovery. Here, we describe a method of preparing powdered GPCRs using rhodopsin as the prototype. We purified rhodopsin in CHAPS detergent with low detergent to protein ratio so the bulk of the sample represented protein (ca. 72% w/w). Our new method for generating powders of membrane proteins followed by rehydration paves the way for conducting functional and biophysical experiments. As an illustrative application, powdered rhodopsin was prepared with and without the cofactor 11-cis-retinal to enable partial rehydration of the protein with D2O in a controlled manner. Quasi-elastic neutron scattering studies using both spatial motion and energy landscape models form the basis for crucial insights into structural fluctuations and thermodynamics of GPCR activation.
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Affiliation(s)
| | - Udeep Chawla
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael F. Brown
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
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31
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Shrestha UR, Perera SMDC, Bhowmik D, Chawla U, Mamontov E, Brown MF, Chu XQ. Quasi-elastic Neutron Scattering Reveals Ligand-Induced Protein Dynamics of a G-Protein-Coupled Receptor. J Phys Chem Lett 2016; 7:4130-4136. [PMID: 27628201 PMCID: PMC5378701 DOI: 10.1021/acs.jpclett.6b01632] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Light activation of the visual G-protein-coupled receptor (GPCR) rhodopsin leads to significant structural fluctuations of the protein embedded within the membrane yielding the activation of cognate G-protein (transducin), which initiates biological signaling. Here, we report a quasi-elastic neutron scattering study of the activation of rhodopsin as a GPCR prototype. Our results reveal a broadly distributed relaxation of hydrogen atom dynamics of rhodopsin on a picosecond-nanosecond time scale, crucial for protein function, as only observed for globular proteins previously. Interestingly, the results suggest significant differences in the intrinsic protein dynamics of the dark-state rhodopsin versus the ligand-free apoprotein, opsin. These differences can be attributed to the influence of the covalently bound retinal ligand. Furthermore, an idea of the generic free-energy landscape is used to explain the GPCR dynamics of ligand-binding and ligand-free protein conformations, which can be further applied to other GPCR systems.
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Affiliation(s)
- Utsab R. Shrestha
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
| | | | - Debsindhu Bhowmik
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
| | - Udeep Chawla
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Eugene Mamontov
- Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Michael F. Brown
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
| | - Xiang-qiang Chu
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
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32
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Ren Z, Ren PX, Balusu R, Yang X. Transmembrane Helices Tilt, Bend, Slide, Torque, and Unwind between Functional States of Rhodopsin. Sci Rep 2016; 6:34129. [PMID: 27658480 PMCID: PMC5034245 DOI: 10.1038/srep34129] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/07/2016] [Indexed: 11/10/2022] Open
Abstract
The seven-helical bundle of rhodopsin and other G-protein coupled receptors undergoes structural rearrangements as the transmembrane receptor protein is activated. These structural changes are known to involve tilting and bending of various transmembrane helices. However, the cause and effect relationship among structural events leading to a cytoplasmic crevasse for G-protein binding is less well defined. Here we present a mathematical model of the protein helix and a simple procedure to determine multiple parameters that offer precise depiction of a helical conformation. A comprehensive survey of bovine rhodopsin structures shows that the helical rearrangements during the activation of rhodopsin involve a variety of angular and linear motions such as torsion, unwinding, and sliding in addition to the previously reported tilting and bending. These hitherto undefined motion components unify the results obtained from different experimental approaches, and demonstrate conformational similarity between the active opsin structure and the photoactivated structures in crystallo near the retinal anchor despite their marked differences.
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Affiliation(s)
- Zhong Ren
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.,Renz Research, Inc., Westmont, IL 60559, USA
| | - Peter X Ren
- Hinsdale Central High School, Hinsdale, IL 60521, USA
| | - Rohith Balusu
- Hinsdale Central High School, Hinsdale, IL 60521, USA
| | - Xiaojing Yang
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Ophthalmology and Vision Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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33
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Ye L, Van Eps N, Zimmer M, Ernst OP, Scott Prosser R. Activation of the A2A adenosine G-protein-coupled receptor by conformational selection. Nature 2016; 533:265-8. [DOI: 10.1038/nature17668] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 03/16/2016] [Indexed: 12/22/2022]
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34
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Functional genomics identifies regulators of the phototransduction machinery in the Drosophila larval eye and adult ocelli. Dev Biol 2016; 410:164-177. [PMID: 26769100 DOI: 10.1016/j.ydbio.2015.12.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/22/2015] [Accepted: 12/22/2015] [Indexed: 11/21/2022]
Abstract
Sensory perception of light is mediated by specialized Photoreceptor neurons (PRs) in the eye. During development all PRs are genetically determined to express a specific Rhodopsin (Rh) gene and genes mediating a functional phototransduction pathway. While the genetic and molecular mechanisms of PR development is well described in the adult compound eye, it remains unclear how the expression of Rhodopsins and the phototransduction cascade is regulated in other visual organs in Drosophila, such as the larval eye and adult ocelli. Using transcriptome analysis of larval PR-subtypes and ocellar PRs we identify and study new regulators required during PR differentiation or necessary for the expression of specific signaling molecules of the functional phototransduction pathway. We found that the transcription factor Krüppel (Kr) is enriched in the larval eye and controls PR differentiation by promoting Rh5 and Rh6 expression. We also identified Camta, Lola, Dve and Hazy as key genes acting during ocellar PR differentiation. Further we show that these transcriptional regulators control gene expression of the phototransduction cascade in both larval eye and adult ocelli. Our results show that PR cell type-specific transcriptome profiling is a powerful tool to identify key transcriptional regulators involved during several aspects of PR development and differentiation. Our findings greatly contribute to the understanding of how combinatorial action of key transcriptional regulators control PR development and the regulation of a functional phototransduction pathway in both larval eye and adult ocelli.
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35
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Sahu B, Sun W, Perusek L, Parmar V, Le YZ, Griswold MD, Palczewski K, Maeda A. Conditional Ablation of Retinol Dehydrogenase 10 in the Retinal Pigmented Epithelium Causes Delayed Dark Adaption in Mice. J Biol Chem 2015; 290:27239-27247. [PMID: 26391396 DOI: 10.1074/jbc.m115.682096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Indexed: 12/29/2022] Open
Abstract
Regeneration of the visual chromophore, 11-cis-retinal, is a crucial step in the visual cycle required to sustain vision. This cycle consists of sequential biochemical reactions that occur in photoreceptor cells and the retinal pigmented epithelium (RPE). Oxidation of 11-cis-retinol to 11-cis-retinal is accomplished by a family of enzymes termed 11-cis-retinol dehydrogenases, including RDH5 and RDH11. Double deletion of Rdh5 and Rdh11 does not limit the production of 11-cis-retinal in mice. Here we describe a third retinol dehydrogenase in the RPE, RDH10, which can produce 11-cis-retinal. Mice with a conditional knock-out of Rdh10 in RPE cells (Rdh10 cKO) displayed delayed 11-cis-retinal regeneration and dark adaption after bright light illumination. Retinal function measured by electroretinogram after light exposure was also delayed in Rdh10 cKO mice as compared with controls. Double deletion of Rdh5 and Rdh10 (cDKO) in mice caused elevated 11/13-cis-retinyl ester content also seen in Rdh5(-/-)Rdh11(-/-) mice as compared with Rdh5(-/-) mice. Normal retinal morphology was observed in 6-month-old Rdh10 cKO and cDKO mice, suggesting that loss of Rdh10 in the RPE does not negatively affect the health of the retina. Compensatory expression of other retinol dehydrogenases was observed in both Rdh5(-/-) and Rdh10 cKO mice. These results indicate that RDH10 acts in cooperation with other RDH isoforms to produce the 11-cis-retinal chromophore needed for vision.
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Affiliation(s)
- Bhubanananda Sahu
- Departments of Ophthalmology and Visual Sciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Wenyu Sun
- Polgenix, Inc., Cleveland, Ohio 44106
| | - Lindsay Perusek
- Departments of Ophthalmology and Visual Sciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Vipulkumar Parmar
- Departments of Ophthalmology and Visual Sciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Yun-Zheng Le
- Departments of Medicine Endocrinology, Cell Biology, and Ophthalmology and the Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Michael D Griswold
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
| | - Krzysztof Palczewski
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106; Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Akiko Maeda
- Departments of Ophthalmology and Visual Sciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106; Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
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36
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Fields MA, Bowrey HE, Gong J, Ablonczy Z, Del Priore LV. Retinoid Processing in Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium Cultures. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:477-90. [PMID: 26310172 DOI: 10.1016/bs.pmbts.2015.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Stem cell therapy for retinal degenerative diseases such as age-related macular degeneration is a promising clinical option for the replacement of photoreceptors and retinal pigment epithelium (RPE). Induced pluripotent stem cell technology has emerged as a viable potential source of cells for transplantation in retinal degenerative disorders. Induced pluripotent stem cells have been used to derive RPE and have been tested for their functional behavior. These cells have the ability to express RPE-specific proteins and morphologically resemble native RPE. Induced pluripotent stem cell-derived RPE are also able to contribute to the visual cycle by their ability to metabolize all-trans retinol, a critical function of RPE in maintaining visual function. Advances in induced pluripotent stem cell technology will contribute to the development of clinical therapies for retinal degenerative diseases as well as provide a tool to understand the pathology of these disorders.
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Affiliation(s)
- Mark A Fields
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.
| | - Hannah E Bowrey
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Jie Gong
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Zsolt Ablonczy
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Lucian V Del Priore
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
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37
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Structural dynamics and energetics underlying allosteric inactivation of the cannabinoid receptor CB1. Proc Natl Acad Sci U S A 2015; 112:8469-74. [PMID: 26100912 DOI: 10.1073/pnas.1500895112] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are surprisingly flexible molecules that can do much more than simply turn on G proteins. Some even exhibit biased signaling, wherein the same receptor preferentially activates different G-protein or arrestin signaling pathways depending on the type of ligand bound. Why this behavior occurs is still unclear, but it can happen with both traditional ligands and ligands that bind allosterically outside the orthosteric receptor binding pocket. Here, we looked for structural mechanisms underlying these phenomena in the marijuana receptor CB1. Our work focused on the allosteric ligand Org 27569, which has an unusual effect on CB1-it simultaneously increases agonist binding, decreases G--protein activation, and induces biased signaling. Using classical pharmacological binding studies, we find that Org 27569 binds to a unique allosteric site on CB1 and show that it can act alone (without need for agonist cobinding). Through mutagenesis studies, we find that the ability of Org 27569 to bind is related to how much receptor is in an active conformation that can couple with G protein. Using these data, we estimated the energy differences between the inactive and active states. Finally, site-directed fluorescence labeling studies show the CB1 structure stabilized by Org 27569 is different and unique from that stabilized by antagonist or agonist. Specifically, transmembrane helix 6 (TM6) movements associated with G-protein activation are blocked, but at the same time, helix 8/TM7 movements are enhanced, suggesting a possible mechanism for the ability of Org 27569 to induce biased signaling.
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38
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Manglik A, Kim TH, Masureel M, Altenbach C, Yang Z, Hilger D, Lerch MT, Kobilka TS, Thian FS, Hubbell WL, Prosser RS, Kobilka BK. Structural Insights into the Dynamic Process of β2-Adrenergic Receptor Signaling. Cell 2015; 161:1101-1111. [PMID: 25981665 DOI: 10.1016/j.cell.2015.04.043] [Citation(s) in RCA: 483] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 03/04/2015] [Accepted: 03/26/2015] [Indexed: 01/01/2023]
Abstract
G-protein-coupled receptors (GPCRs) transduce signals from the extracellular environment to intracellular proteins. To gain structural insight into the regulation of receptor cytoplasmic conformations by extracellular ligands during signaling, we examine the structural dynamics of the cytoplasmic domain of the β2-adrenergic receptor (β2AR) using (19)F-fluorine NMR and double electron-electron resonance spectroscopy. These studies show that unliganded and inverse-agonist-bound β2AR exists predominantly in two inactive conformations that exchange within hundreds of microseconds. Although agonists shift the equilibrium toward a conformation capable of engaging cytoplasmic G proteins, they do so incompletely, resulting in increased conformational heterogeneity and the coexistence of inactive, intermediate, and active states. Complete transition to the active conformation requires subsequent interaction with a G protein or an intracellular G protein mimetic. These studies demonstrate a loose allosteric coupling of the agonist-binding site and G-protein-coupling interface that may generally be responsible for the complex signaling behavior observed for many GPCRs.
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Affiliation(s)
- Aashish Manglik
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Tae Hun Kim
- Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada
| | - Matthieu Masureel
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Christian Altenbach
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-7008, USA
| | - Zhongyu Yang
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-7008, USA
| | - Daniel Hilger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Michael T Lerch
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-7008, USA
| | - Tong Sun Kobilka
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Foon Sun Thian
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Wayne L Hubbell
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-7008, USA
| | - R Scott Prosser
- Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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39
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Brunk E, Rothlisberger U. Mixed Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulations of Biological Systems in Ground and Electronically Excited States. Chem Rev 2015; 115:6217-63. [PMID: 25880693 DOI: 10.1021/cr500628b] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Elizabeth Brunk
- †Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.,‡Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, California 94618, United States
| | - Ursula Rothlisberger
- †Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.,§National Competence Center of Research (NCCR) MARVEL-Materials' Revolution: Computational Design and Discovery of Novel Materials, 1015 Lausanne, Switzerland
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40
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Structure-Based Biophysical Analysis of the Interaction of Rhodopsin with G Protein and Arrestin. Methods Enzymol 2015; 556:563-608. [DOI: 10.1016/bs.mie.2014.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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41
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Mooney V, Sekharan S, Liu J, Guo Y, Batista VS, Yan ECY. Kinetics of thermal activation of an ultraviolet cone pigment. J Am Chem Soc 2014; 137:307-13. [PMID: 25514632 DOI: 10.1021/ja510553f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Visual pigments can be thermally activated via isomerization of the retinyl chromophore and hydrolysis of the Schiff base (SB) through which the retinyl chromophore is bound to the opsin protein. Here, we present the first combined experimental and theoretical study of the thermal activation of a Siberian hamster ultraviolet (SHUV) pigment. We measured the rates of thermal isomerization and hydrolysis in the SHUV pigment and bovine rhodopsin. We found that these rates were significantly faster in the UV pigment than in rhodopsin due to the difference in the structural and electrostatic effects surrounding the unprotonated Schiff base (USB) retinyl chromophore in the UV pigment. Theoretical (DFT-QM/MM) calculations of the cis-trans thermal isomerization revealed a barrier of ∼23 kcal/mol for the USB retinyl chromophore in SHUV compared to ∼40 kcal/mol for protonated Schiff base (PSB) chromophore in rhodopsin. The lower barrier for thermal isomerization in the SHUV pigment is attributed to the (i) lessening of the steric restraints near the β-ionone ring and SB ends of the chromophore, (ii) displacement of the transmembrane helix 6 (TM6) away from the binding pocket toward TM5 due to absence of the salt bridge between the USB and the protonated E113 residue, and (iii) change in orientation of the hydrogen-bonding networks (HBNs) in the extracellular loop 2 (EII). The results in comparing thermal stability of UV cone pigment and rhodopsin provide insight into molecular evolution of vertebrate visual pigments in achieving low discrete dark noise and high photosensitivity in rod pigments for dim-light vision.
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Affiliation(s)
- Victoria Mooney
- Department of Chemistry, Yale University , New Haven, Connecticut 06520 United States
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42
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Abstract
The melanocortin 3 receptor (MC3R) regulates several physiological functions, including feed efficiency, nutrient partitioning, fasting response, natriuresis, and immune reactions. Naturally occurring mutations in the MC3R gene have been shown to be associated with increased adiposity and lung diseases such as tuberculosis and cystic fibrosis. The DRY motif at the cytoplasmic end of transmembrane domain 3 (TM3) and the second intracellular loop 2 (ICL2) are known to be important for receptor function in several G protein-coupled receptors (GPCRs). To gain a better understanding of the functions of this domain in MC3R, we performed alanine-scanning mutagenesis on 18 residues. We showed that alanine mutation of 11 residues reduced the maximal binding and maximal cAMP production stimulated by agonists. Mutation of two residues did not change maximal binding but resulted in impaired signaling in the Gs-cAMP pathway. Mutation of five residues impaired signaling in the ERK1/2 pathway. We have also shown that alanine mutants of seven residues that were defective in the cAMP pathway were not defective in the ERK1/2 pathway, demonstrating biased signaling. In summary, we demonstrated that the cytoplasmic end of TM3 and the ICL2 were critical for MC3R function. We also reported for the first time biased signaling in MC3R.
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Affiliation(s)
- Hui Huang
- Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USA
| | - Ya-Xiong Tao
- Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USA
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43
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Palczewski K. Chemistry and biology of the initial steps in vision: the Friedenwald lecture. Invest Ophthalmol Vis Sci 2014; 55:6651-72. [PMID: 25338686 DOI: 10.1167/iovs.14-15502] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Visual transduction is the process in the eye whereby absorption of light in the retina is translated into electrical signals that ultimately reach the brain. The first challenge presented by visual transduction is to understand its molecular basis. We know that maintenance of vision is a continuous process requiring the activation and subsequent restoration of a vitamin A-derived chromophore through a series of chemical reactions catalyzed by enzymes in the retina and retinal pigment epithelium (RPE). Diverse biochemical approaches that identified key proteins and reactions were essential to achieve a mechanistic understanding of these visual processes. The three-dimensional arrangements of these enzymes' polypeptide chains provide invaluable insights into their mechanisms of action. A wealth of information has already been obtained by solving high-resolution crystal structures of both rhodopsin and the retinoid isomerase from pigment RPE (RPE65). Rhodopsin, which is activated by photoisomerization of its 11-cis-retinylidene chromophore, is a prototypical member of a large family of membrane-bound proteins called G protein-coupled receptors (GPCRs). RPE65 is a retinoid isomerase critical for regeneration of the chromophore. Electron microscopy (EM) and atomic force microscopy have provided insights into how certain proteins are assembled to form much larger structures such as rod photoreceptor cell outer segment membranes. A second challenge of visual transduction is to use this knowledge to devise therapeutic approaches that can prevent or reverse conditions leading to blindness. Imaging modalities like optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) applied to appropriate animal models as well as human retinal imaging have been employed to characterize blinding diseases, monitor their progression, and evaluate the success of therapeutic agents. Lately two-photon (2-PO) imaging, together with biochemical assays, are revealing functional aspects of vision at a new molecular level. These multidisciplinary approaches combined with suitable animal models and inbred mutant species can be especially helpful in translating provocative cell and tissue culture findings into therapeutic options for further development in animals and eventually in humans. A host of different approaches and techniques is required for substantial progress in understanding fundamental properties of the visual system.
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Affiliation(s)
- Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
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44
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Unusual kinetics of thermal decay of dim-light photoreceptors in vertebrate vision. Proc Natl Acad Sci U S A 2014; 111:10438-43. [PMID: 25002518 DOI: 10.1073/pnas.1410826111] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present measurements of rate constants for thermal-induced reactions of the 11-cis retinyl chromophore in vertebrate visual pigment rhodopsin, a process that produces noise and limits the sensitivity of vision in dim light. At temperatures of 52.0-64.6 °C, the rate constants fit well to an Arrhenius straight line with, however, an unexpectedly large activation energy of 114 ± 8 kcal/mol, which is much larger than the 60-kcal/mol photoactivation energy at 500 nm. Moreover, we obtain an unprecedentedly large prefactor of 10(72±5) s(-1), which is roughly 60 orders of magnitude larger than typical frequencies of molecular motions! At lower temperatures, the measured Arrhenius parameters become more normal: Ea = 22 ± 2 kcal/mol and Apref = 10(9±1) s(-1) in the range of 37.0-44.5 °C. We present a theoretical framework and supporting calculations that attribute this unusual temperature-dependent kinetics of rhodopsin to a lowering of the reaction barrier at higher temperatures due to entropy-driven partial breakup of the rigid hydrogen-bonding network that hinders the reaction at lower temperatures.
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45
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Wu YL, Li J, Yao K. Structures and biogenetic analysis of lipofuscin bis-retinoids. J Zhejiang Univ Sci B 2014; 14:763-73. [PMID: 24009196 DOI: 10.1631/jzus.b1300051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Age-related macular degeneration (AMD) is still an incurable blinding eye disease because of complex pathogenic mechanisms and unusual diseased regions. With the use of chemical biology tools, great progress has been achieved in improving the understanding of AMD pathogenesis. The severity of AMD is, at least in part, linked to the non-degradable lipofuscin bis-retinoids in retinal pigment epithelial (RPE). This material is thought to result from the lifelong accumulation of lysosomal residual bodies containing the end products derived from the daily phagocytosis of rod outer segments by RPE cells. Here, we present previously recognized bis-retinoids with focus on structures and biosynthetic pathways. In addition to a brief discussion on the mutual conversion relationships of bis-retinoids, future perspectives and the medical relevance of such studies on these lipofuscin constituents are also highlighted.
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Affiliation(s)
- Ya-lin Wu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
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46
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Katritch V, Fenalti G, Abola EE, Roth BL, Cherezov V, Stevens RC. Allosteric sodium in class A GPCR signaling. Trends Biochem Sci 2014; 39:233-44. [PMID: 24767681 DOI: 10.1016/j.tibs.2014.03.002] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 01/16/2023]
Abstract
Despite their functional and structural diversity, G-protein-coupled receptors (GPCRs) share a common mechanism of signal transduction via conformational changes in the seven-transmembrane (7TM) helical domain. New major insights into this mechanism come from the recent crystallographic discoveries of a partially hydrated sodium ion that is specifically bound in the middle of the 7TM bundle of multiple class A GPCRs. This review discusses the remarkable structural conservation and distinct features of the Na(+) pocket in this most populous GPCR class, as well as the conformational collapse of the pocket upon receptor activation. New insights help to explain allosteric effects of sodium on GPCR agonist binding and activation, and sodium's role as a potential co-factor in class A GPCR function.
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Affiliation(s)
- Vsevolod Katritch
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Gustavo Fenalti
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Enrique E Abola
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Bryan L Roth
- National Institute of Mental Health Psychoactive Drug Screening Program, Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27599, USA
| | - Vadim Cherezov
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Raymond C Stevens
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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47
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Yamazaki Y, Nagata T, Terakita A, Kandori H, Shichida Y, Imamoto Y. Intramolecular interactions that induce helical rearrangement upon rhodopsin activation: light-induced structural changes in metarhodopsin IIa probed by cysteine S-H stretching vibrations. J Biol Chem 2014; 289:13792-800. [PMID: 24692562 DOI: 10.1074/jbc.m113.527606] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rhodopsin undergoes rearrangements of its transmembrane helices after photon absorption to transfer a light signal to the G-protein transducin. To investigate the mechanism by which rhodopsin adopts the transducin-activating conformation, the local environmental changes in the transmembrane region were probed using the cysteine S-H group, whose stretching frequency is well isolated from the other protein vibrational modes. The S-H stretching modes of cysteine residues introduced into Helix III, which contains several key residues for the helical movements, and of native cysteine residues were measured by Fourier transform infrared spectroscopy. This method was applied to metarhodopsin IIa, a precursor of the transducin-activating state in which the intramolecular interactions are likely to produce a state ready for helical movements. No environmental change was observed near the ionic lock between Arg-135 in Helix III and Glu-247 in Helix VI that maintains the inactive conformation. Rather, the cysteine residues that showed environmental changes were located around the chromophore, Ala-164, His-211, and Phe-261. These findings imply that the hydrogen bond between Helix III and Helix V involving Glu-122 and His-211 and the hydrophobic packing between Helix III and Helix VI involving Gly-121, Leu-125, Phe-261, and Trp-265 are altered before the helical rearrangement leading toward the active conformation.
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Affiliation(s)
- Yoichi Yamazaki
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Graduate School of Materials Science, Nara Institute of Science and Technology, Nara, 630-0192, Japan
| | - Tomoko Nagata
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Akihisa Terakita
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan, and
| | - Hideki Kandori
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yoshinori Shichida
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yasushi Imamoto
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan,
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48
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Campomanes P, Neri M, Horta BAC, Röhrig UF, Vanni S, Tavernelli I, Rothlisberger U. Origin of the Spectral Shifts among the Early Intermediates of the Rhodopsin Photocycle. J Am Chem Soc 2014; 136:3842-51. [DOI: 10.1021/ja411303v] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Pablo Campomanes
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Marilisa Neri
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Bruno A. C. Horta
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ute F. Röhrig
- Molecular Modeling
Group, Swiss Institute of
Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Stefano Vanni
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ivano Tavernelli
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ursula Rothlisberger
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
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49
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Leioatts N, Mertz B, Martínez-Mayorga K, Romo TD, Pitman MC, Feller SE, Grossfield A, Brown MF. Retinal ligand mobility explains internal hydration and reconciles active rhodopsin structures. Biochemistry 2014; 53:376-85. [PMID: 24328554 DOI: 10.1021/bi4013947] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rhodopsin, the mammalian dim-light receptor, is one of the best-characterized G-protein-coupled receptors, a pharmaceutically important class of membrane proteins that has garnered a great deal of attention because of the recent availability of structural information. Yet the mechanism of rhodopsin activation is not fully understood. Here, we use microsecond-scale all-atom molecular dynamics simulations, validated by solid-state (2)H nuclear magnetic resonance spectroscopy, to understand the transition between the dark and metarhodopsin I (Meta I) states. Our analysis of these simulations reveals striking differences in ligand flexibility between the two states. Retinal is much more dynamic in Meta I, adopting an elongated conformation similar to that seen in the recent activelike crystal structures. Surprisingly, this elongation corresponds to both a dramatic influx of bulk water into the hydrophobic core of the protein and a concerted transition in the highly conserved Trp265(6.48) residue. In addition, enhanced ligand flexibility upon light activation provides an explanation for the different retinal orientations observed in X-ray crystal structures of active rhodopsin.
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Affiliation(s)
- Nicholas Leioatts
- Department of Biochemistry and Biophysics, University of Rochester Medical Center , Rochester, New York 14642, United States
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50
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Ernst OP, Lodowski DT, Elstner M, Hegemann P, Brown L, Kandori H. Microbial and animal rhodopsins: structures, functions, and molecular mechanisms. Chem Rev 2014; 114:126-63. [PMID: 24364740 PMCID: PMC3979449 DOI: 10.1021/cr4003769] [Citation(s) in RCA: 771] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Oliver P. Ernst
- Departments
of Biochemistry and Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada
| | - David T. Lodowski
- Center
for Proteomics and Bioinformatics, Case
Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Marcus Elstner
- Institute
for Physical Chemistry, Karlsruhe Institute
of Technology, Kaiserstrasse
12, 76131 Karlsruhe, Germany
| | - Peter Hegemann
- Institute
of Biology, Experimental Biophysics, Humboldt-Universität
zu Berlin, Invalidenstrasse
42, 10115 Berlin, Germany
| | - Leonid
S. Brown
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Hideki Kandori
- Department
of Frontier Materials, Nagoya Institute
of Technology, Showa-ku, Nagoya 466-8555, Japan
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