1
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Gonzalez-Fernandez F, DeSa R. Obtaining absorbance spectra from turbid retinal cell and tissue suspensions - Beating the light-scatter problem. Exp Eye Res 2023; 230:109434. [PMID: 36878422 DOI: 10.1016/j.exer.2023.109434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 01/03/2023] [Accepted: 03/03/2023] [Indexed: 03/07/2023]
Abstract
Light scattering and inability to uniformly expose the cuvette contents to an incident light beam are significant limitations of traditional spectrophotometers. The first of these drawbacks limits their usefulness in studies of turbid cellular and tissue suspensions; the second limits their use in photodecomposition studies. Our strategy circumvents both problems. Although we describe its potential usefulness in vision sciences, application of spherical integrating cuvettes has broad application. Absorbance spectra of turbid bovine rod outer segments and dispersed living frog retina were studied using a standard single-pass 1 cm cuvettes, or a spherical integrating cuvette (DeSa Presentation Chamber, DSPC). The DSPC was mounted on an OLIS Rapid Scanning Spectrophotometer configured to generate 100 spectral scans/sec. To follow rhodopsin bleaching kinetics in living photoreceptors, portions of dark-adapted frog retina were suspended in the DSPC. The incoming spectral beam at 2 scans/sec entered the chamber through a single port. Separate ports contained a 519 nm light emitting diode (LED), or window to the photomultiplier tube. The surface of the DSPC was coated with a highly reflective coating allowing the chamber to act as a multi-pass cuvette. The LED is triggered to flash and the PMT shutter temporarily closed during a "Dark-Interval" between each spectral scan. By interleafing scans with LED pulses, spectra changes can be followed in real time. Kinetic analysis of the 3-dimensional data was performed by Singular Value Decomposition. For crude bovine rod outer segment suspensions, the 1 cm single-pass traditional cuvette gave non-informative spectra dominated by high absorbances and Rayleigh scattering. In contrast, spectra generated using the DSPC showed low overall absorbance with peaks at 405 and 503 nm. The later peak disappeared with exposure to white light in presence of 100 mM hydroxylamine. For the dispersed living retinal, the sample was pulsed at 519 nm between the spectra. The 495 nm rhodopsin peak gradually reduced in size concomitant with the emergence of a 400 nm peak, probably representing Meta II. A conversion mechanism of two species, A → B with rate constant of 0.132 sec-1 was fit to the data. To our knowledge this is the first application of integrating sphere technology to retinal spectroscopy. Remarkably, the spherical cuvette designed for total internal reflectance to produce diffused light was efffectively immune to light scattering. Furthermore, the higher effective path length enhanced sensitivity and could be accounted for mathematically allowing determination of absorbance/cm. The approach, which complements the use of the CLARiTy RSM 1000 for photodecomposition studies (Gonzalez-Fernandez et al. Mol Vis 2016, 22:953), may facilitate studies of metabolically active photoreceptor suspensions or whole retinas in physiological assays.
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Affiliation(s)
- Federico Gonzalez-Fernandez
- Research Service, Veterans Affairs Medical Center, Jackson, MS, 39216, USA; Department of Ophthalmology and Pathology, University of Mississippi Medical School, Jackson, MS, 39216, USA; PathRD Inc., Jackson, MS, 39212, USA.
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2
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Vats A, Xi Y, Feng B, Clinger OD, St Leger AJ, Liu X, Ghosh A, Dermond CD, Lathrop KL, Tochtrop GP, Picaud S, Chen Y. Non-retinoid chaperones improve rhodopsin homeostasis in a mouse model of retinitis pigmentosa. JCI Insight 2022; 7:153717. [PMID: 35472194 PMCID: PMC9220944 DOI: 10.1172/jci.insight.153717] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
Rhodopsin-associated (RHO-associated) retinitis pigmentosa (RP) is a progressive retinal disease that currently has no cure. RHO protein misfolding leads to disturbed proteostasis and the death of rod photoreceptors, resulting in decreased vision. We previously identified nonretinoid chaperones of RHO, including YC-001 and F5257-0462, by small-molecule high-throughput screening. Here, we profile the chaperone activities of these molecules toward the cell-surface level of 27 RP-causing human RHO mutants in NIH3T3 cells. Furthermore, using retinal explant culture, we show that YC-001 improves retinal proteostasis by supporting RHO homeostasis in RhoP23H/+ mouse retinae, which results in thicker outer nuclear layers (ONL), indicating delayed photoreceptor degeneration. Interestingly, YC-001 ameliorated retinal immune responses and reduced the number of microglia/macrophages in the RhoP23H/+ retinal explants. Similarly, F5257-0462 also protects photoreceptors in RhoP23H/+ retinal explants. In vivo, intravitreal injection of YC-001 or F5257-0462 microparticles in PBS shows that F5257-0462 has a higher efficacy in preserving photoreceptor function and delaying photoreceptor death in RhoP23H/+ mice. Collectively, we provide proof of principle that nonretinoid chaperones are promising drug candidates in treating RHO-associated RP.
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Affiliation(s)
- Abhishek Vats
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Yibo Xi
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Bing Feng
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Owen D Clinger
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Anthony J St Leger
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Archisha Ghosh
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Chase D Dermond
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Kira L Lathrop
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, Cleveland, United States of America
| | - Serge Picaud
- Institut de la Vision, Sorbonne Université, Paris, France
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
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3
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Liu X, Feng B, Vats A, Tang H, Seibel W, Swaroop M, Tawa G, Zheng W, Byrne L, Schurdak M, Chen Y. Pharmacological clearance of misfolded rhodopsin for the treatment of RHO-associated retinitis pigmentosa. FASEB J 2020; 34:10146-10167. [PMID: 32536017 DOI: 10.1096/fj.202000282r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 01/20/2023]
Abstract
Rhodopsin mutation and misfolding is a common cause of autosomal dominant retinitis pigmentosa (RP). Using a luciferase reporter assay, we undertook a small-molecule high-throughput screening (HTS) of 68, 979 compounds and identified nine compounds that selectively reduced the misfolded P23H rhodopsin without an effect on the wild type (WT) rhodopsin protein. Further, we found five of these compounds, including methotrexate (MTX), promoted P23H rhodopsin degradation that also cleared out other misfolded rhodopsin mutant proteins. We showed MTX increased P23H rhodopsin degradation via the lysosomal but not the proteasomal pathway. Importantly, one intravitreal injection (IVI) of 25 pmol MTX increased electroretinogram (ERG) response and rhodopsin level in the retinae of RhoP23H/+ knock-in mice at 1 month of age. Additionally, four weekly IVIs increased the photoreceptor cell number in the retinae of RhoP23H/+ mice compared to vehicle control. Our study indicates a therapeutic potential of repurposing MTX for the treatment of rhodopsin-associated RP.
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Affiliation(s)
- Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Feng
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Abhishek Vats
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hong Tang
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA
| | - William Seibel
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA.,Oncology Department, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Manju Swaroop
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Gregory Tawa
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Leah Byrne
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mark Schurdak
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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4
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Scott BM, Wybenga-Groot LE, McGlade CJ, Heon E, Peisajovich SG, Chang BSW. Screening of Chemical Libraries Using a Yeast Model of Retinal Disease. SLAS DISCOVERY 2019; 24:969-977. [PMID: 31556794 DOI: 10.1177/2472555219875934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Retinitis pigmentosa (RP) is a degenerative retinal disease, often caused by mutations in the G-protein-coupled receptor rhodopsin. The majority of pathogenic rhodopsin mutations cause rhodopsin to misfold, including P23H, disrupting its crucial ability to respond to light. Previous screens to discover pharmacological chaperones of rhodopsin have primarily been based on rescuing rhodopsin trafficking and localization to the plasma membrane. Here, we present methods utilizing a yeast-based assay to screen for compounds that rescue the ability of rhodopsin to activate an associated downstream G-protein signaling cascade. We engineered a yeast strain in which human rhodopsin variants were genomically integrated, and were able to demonstrate functional coupling to the yeast mating pathway, leading to fluorescent protein expression. We confirmed that a known pharmacological chaperone, 9-cis retinal, could partially rescue light-dependent activation of a disease-associated rhodopsin mutation (P23H) expressed in yeast. These novel yeast strains were used to perform a phenotypic screen of 4280 compounds from the LOPAC1280 library and a peptidomimetic library, to discover novel pharmacological chaperones of rhodopsin. The fluorescence-based assay was robust in a 96-well format, with a Z' factor of 0.65 and a signal-to-background ratio of above 14. One compound was selected for additional analysis, but it did not appear to rescue rhodopsin function in yeast. The methods presented here are amenable to future screens of small-molecule libraries, as they are robust and cost-effective. We also discuss how these methods could be further modified or adapted to perform screens of more compounds in the future.
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Affiliation(s)
- Benjamin M Scott
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.,Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA.,Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | | | - C Jane McGlade
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Elise Heon
- Department of Ophthalmology and Vision Science, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sergio G Peisajovich
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Belinda S W Chang
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, ON, Canada
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5
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Getter T, Gulati S, Zimmerman R, Chen Y, Vinberg F, Palczewski K. Stereospecific modulation of dimeric rhodopsin. FASEB J 2019; 33:9526-9539. [PMID: 31121099 PMCID: PMC6662988 DOI: 10.1096/fj.201900443rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/23/2019] [Indexed: 11/11/2022]
Abstract
The classic concept that GPCRs function as monomers has been challenged by the emerging evidence of GPCR dimerization and oligomerization. Rhodopsin (Rh) is the only GPCR whose native oligomeric arrangement was revealed by atomic force microscopy demonstrating that Rh exists as a dimer. However, the role of Rh dimerization in retinal physiology is currently unknown. In this study, we identified econazole and sulconazole, two small molecules that disrupt Rh dimer contacts, by implementing a cell-based high-throughput screening assay. Racemic mixtures of identified lead compounds were separated and tested for their stereospecific binding to Rh using UV-visible spectroscopy and intrinsic fluorescence of tryptophan (Trp) 265 after illumination. By following the changes in UV-visible spectra and Trp265 fluorescence in vitro, we found that binding of R-econazole modulates the formation of Meta III and quenches the intrinsic fluorescence of Trp265. In addition, electrophysiological ex vivo recording revealed that R-econazole slows photoresponse kinetics, whereas S-econazole decreased the sensitivity of rods without effecting the kinetics. Thus, this study contributes new methodology to identify compounds that disrupt the dimerization of GPCRs in general and validates the first active compounds that disrupt the Rh dimer specifically.-Getter, T., Gulati, S., Zimmerman, R., Chen, Y., Vinberg, F., Palczewski, K. Stereospecific modulation of dimeric rhodopsin.
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Affiliation(s)
- Tamar Getter
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Sahil Gulati
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, University of California–Irvine, Irvine, California, USA
| | - Remy Zimmerman
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
| | - Yuanyuan Chen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Frans Vinberg
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, University of California–Irvine, Irvine, California, USA
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6
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Park PSH. Rhodopsin Oligomerization and Aggregation. J Membr Biol 2019; 252:413-423. [PMID: 31286171 DOI: 10.1007/s00232-019-00078-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/25/2019] [Indexed: 12/18/2022]
Abstract
Rhodopsin is the light receptor in photoreceptor cells of the retina and a prototypical G protein-coupled receptor. Two types of quaternary structures can be adopted by rhodopsin. If rhodopsin folds and attains a proper tertiary structure, it can then form oligomers and nanodomains within the photoreceptor cell membrane. In contrast, if rhodopsin misfolds, it cannot progress through the biosynthetic pathway and instead will form aggregates that can cause retinal degenerative disease. In this review, emerging views are highlighted on the supramolecular organization of rhodopsin within the membrane of photoreceptor cells and the aggregation of rhodopsin that can lead to retinal degeneration.
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Affiliation(s)
- Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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7
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Mitchell J, Balem F, Tirupula K, Man D, Dhiman HK, Yanamala N, Ollesch J, Planas-Iglesias J, Jennings BJ, Gerwert K, Iannaccone A, Klein-Seetharaman J. Comparison of the molecular properties of retinitis pigmentosa P23H and N15S amino acid replacements in rhodopsin. PLoS One 2019; 14:e0214639. [PMID: 31100078 PMCID: PMC6524802 DOI: 10.1371/journal.pone.0214639] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 03/19/2019] [Indexed: 12/16/2022] Open
Abstract
Mutations in the RHO gene encoding for the visual pigment protein, rhodopsin, are among the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Previous studies of ADRP mutations in different domains of rhodopsin have indicated that changes that lead to more instability in rhodopsin structure are responsible for more severe disease in patients. Here, we further test this hypothesis by comparing side-by-side and therefore quantitatively two RHO mutations, N15S and P23H, both located in the N-terminal intradiscal domain. The in vitro biochemical properties of these two rhodopsin proteins, expressed in stably transfected tetracycline-inducible HEK293S cells, their UV-visible absorption, their Fourier transform infrared, circular dichroism and Metarhodopsin II fluorescence spectroscopy properties were characterized. As compared to the severely impaired P23H molecular function, N15S is only slightly defective in structure and stability. We propose that the molecular basis for these structural differences lies in the greater distance of the N15 residue as compared to P23 with respect to the predicted rhodopsin folding core. As described previously for WT rhodopsin, addition of the cytoplasmic allosteric modulator chlorin e6 stabilizes especially the P23H protein, suggesting that chlorin e6 may be generally beneficial in the rescue of those ADRP rhodopsin proteins whose stability is affected by amino acid replacement.
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Affiliation(s)
- James Mitchell
- Division of Biomedical Sciences, Medical School, University of Warwick, Coventry, United Kingdom
| | - Fernanda Balem
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kalyan Tirupula
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - David Man
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Harpreet Kaur Dhiman
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Naveena Yanamala
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Julian Ollesch
- Department of Biophysics, Ruhr-University Bochum, Bochum, Germany
| | - Joan Planas-Iglesias
- Division of Biomedical Sciences, Medical School, University of Warwick, Coventry, United Kingdom
| | - Barbara J Jennings
- Retinal Degeneration & Ophthalmic Genetics Service & Lions Visual Function Diagnostic Lab, Hamilton Eye Institute, Dept. Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Klaus Gerwert
- Department of Biophysics, Ruhr-University Bochum, Bochum, Germany
| | - Alessandro Iannaccone
- Retinal Degeneration & Ophthalmic Genetics Service & Lions Visual Function Diagnostic Lab, Hamilton Eye Institute, Dept. Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Judith Klein-Seetharaman
- Division of Biomedical Sciences, Medical School, University of Warwick, Coventry, United Kingdom
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
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8
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Feng B, Liu X, Chen Y. A Rhodopsin Transport Assay by High-Content Imaging Analysis. J Vis Exp 2019. [PMID: 30735172 DOI: 10.3791/58703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Rhodopsin misfolding mutations lead to rod photoreceptor death that is manifested as autosomal dominant retinitis pigmentosa (RP), a progressive blinding disease that lacks effective treatment. We hypothesize that the cytotoxicity of the misfolded rhodopsin mutant can be alleviated by pharmacologically stabilizing the mutant rhodopsin protein. The P23H mutation, among the other Class II rhodopsin mutations, encodes a structurally unstable rhodopsin mutant protein that is accumulated in the endoplasmic reticulum (ER), whereas the wild type rhodopsin is transported to the plasma membrane in mammalian cells. We previously performed a luminescence-based high-throughput screen (HTS) and identified a group of pharmacological chaperones that rescued the transport of the P23H rhodopsin from ER to the plasma membrane. Here, using an immunostaining method followed by a high-content imaging analysis, we quantified the mutant rhodopsin protein amount in the whole cell and on the plasma membrane. This method is informative and effective to identify true hits from false positives following HTS. Additionally, the high-content image analysis enabled us to quantify multiple parameters from a single experiment to evaluate the pharmacological properties of each compound. Using this assay, we analyzed the effect of 11 different compounds towards six RP associated rhodopsin mutants, obtaining a 2-D pharmacological profile for a quantitative and qualitative understanding about the structural stability of these rhodopsin mutants and efficacy of different compounds towards these mutants.
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Affiliation(s)
- Bing Feng
- Department of Ophthalmology, University of Pittsburgh
| | - Xujie Liu
- Department of Ophthalmology, University of Pittsburgh
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh; McGowan Institute for Regenerative Medicine, University of Pittsburgh;
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9
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Sakami S, Imanishi Y, Palczewski K. Müller glia phagocytose dead photoreceptor cells in a mouse model of retinal degenerative disease. FASEB J 2018; 33:3680-3692. [PMID: 30462532 DOI: 10.1096/fj.201801662r] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Retinitis pigmentosa is a devastating, blinding disorder that affects 1 in 4000 people worldwide. During the progression of the disorder, phagocytic clearance of dead photoreceptor cell bodies has a protective role by preventing additional retinal damage from accumulation of cellular debris. However, the cells responsible for the clearance remain unidentified. Taking advantage of a mouse model of retinitis pigmentosa ( RhoP23H/P23H), we clarified the roles of Müller glia in the phagocytosis of rod photoreceptor cells. During the early stage of retinal degeneration, Müller glial cells participated in the phagocytosis of dying or dead rod photoreceptors throughout the outer nuclear layer. Nearly 50% of Müller glia engaged in phagocytosis. Among the Müller phagosomes, >90% matured into phagolysosomes. Those observations indicated that Müller glial cells are the primary contributor to phagocytosis. In contrast, macrophages migrate to the inner part of the outer nuclear layer during photoreceptor degeneration, participating in the phagocytosis of a limited population of dying or dead photoreceptor cells. In healthy retinas of wild-type mice, Müller glial cells phagocytosed cell bodies of dead rod photoreceptors albeit at a lower frequency. Taken together, the phagocytic function of Müller glia is responsible for retinal homeostasis and reorganization under normal and pathologic conditions.-Sakami, S., Imanishi, Y., Palczewski, K. Müller glia phagocytose dead photoreceptor cells in a mouse model of retinal degenerative disease.
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Affiliation(s)
- Sanae Sakami
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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10
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Misfolded rhodopsin mutants display variable aggregation properties. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2938-2948. [PMID: 29890221 DOI: 10.1016/j.bbadis.2018.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/31/2018] [Accepted: 06/06/2018] [Indexed: 11/20/2022]
Abstract
The largest class of rhodopsin mutations causing autosomal dominant retinitis pigmentosa (adRP) is mutations that lead to misfolding and aggregation of the receptor. The misfolding mutants have been characterized biochemically, and categorized as either partial or complete misfolding mutants. This classification is incomplete and does not provide sufficient information to fully understand the disease pathogenesis and evaluate therapeutic strategies. A Förster resonance energy transfer (FRET) method was utilized to directly assess the aggregation properties of misfolding rhodopsin mutants within the cell. Partial (P23H and P267L) and complete (G188R, H211P, and P267R) misfolding mutants were characterized to reveal variability in aggregation properties. The complete misfolding mutants all behaved similarly, forming aggregates when expressed alone, minimally interacting with the wild-type receptor when coexpressed, and were unresponsive to treatment with the pharmacological chaperone 9-cis retinal. In contrast, variability was observed between the partial misfolding mutants. In the opsin form, the P23H mutant behaved similarly as the complete misfolding mutants. In contrast, the opsin form of the P267L mutant existed as both aggregates and oligomers when expressed alone and formed mostly oligomers with the wild-type receptor when coexpressed. The partial misfolding mutants both reacted similarly to the pharmacological chaperone 9-cis retinal, displaying improved folding and oligomerization when expressed alone but aggregating with wild-type receptor when coexpressed. The observed differences in aggregation properties and effect of 9-cis retinal predict different outcomes in disease pathophysiology and suggest that retinoid-based chaperones will be ineffective or even detrimental.
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11
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Chen Y, Chen Y, Jastrzebska B, Golczak M, Gulati S, Tang H, Seibel W, Li X, Jin H, Han Y, Gao S, Zhang J, Liu X, Heidari-Torkabadi H, Stewart PL, Harte WE, Tochtrop GP, Palczewski K. A novel small molecule chaperone of rod opsin and its potential therapy for retinal degeneration. Nat Commun 2018; 9:1976. [PMID: 29773803 PMCID: PMC5958115 DOI: 10.1038/s41467-018-04261-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 04/13/2018] [Indexed: 12/21/2022] Open
Abstract
Rhodopsin homeostasis is tightly coupled to rod photoreceptor cell survival and vision. Mutations resulting in the misfolding of rhodopsin can lead to autosomal dominant retinitis pigmentosa (adRP), a progressive retinal degeneration that currently is untreatable. Using a cell-based high-throughput screen (HTS) to identify small molecules that can stabilize the P23H-opsin mutant, which causes most cases of adRP, we identified a novel pharmacological chaperone of rod photoreceptor opsin, YC-001. As a non-retinoid molecule, YC-001 demonstrates micromolar potency and efficacy greater than 9-cis-retinal with lower cytotoxicity. YC-001 binds to bovine rod opsin with an EC50 similar to 9-cis-retinal. The chaperone activity of YC-001 is evidenced by its ability to rescue the transport of multiple rod opsin mutants in mammalian cells. YC-001 is also an inverse agonist that non-competitively antagonizes rod opsin signaling. Significantly, a single dose of YC-001 protects Abca4 -/- Rdh8 -/- mice from bright light-induced retinal degeneration, suggesting its broad therapeutic potential.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- The McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive Suite 300, Pittsburgh, PA, 15219, USA.
- Department of Ophthalmology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA, 15260, USA.
| | - Yu Chen
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, 200437, Shanghai, China
| | - Beata Jastrzebska
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 E. 101st Street, Cleveland, OH, 44106, USA
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 E. 101st Street, Cleveland, OH, 44106, USA
| | - Sahil Gulati
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 E. 101st Street, Cleveland, OH, 44106, USA
| | - Hong Tang
- Drug Discovery Center, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH, 45237, USA
| | - William Seibel
- Drug Discovery Center, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH, 45237, USA
| | - Xiaoyu Li
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Hui Jin
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Yong Han
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Songqi Gao
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Jianye Zhang
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA, 15260, USA
| | - Hossein Heidari-Torkabadi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Phoebe L Stewart
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 E. 101st Street, Cleveland, OH, 44106, USA
| | - William E Harte
- Office of Translation and Innovation, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 E. 101st Street, Cleveland, OH, 44106, USA.
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12
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Mattle D, Kuhn B, Aebi J, Bedoucha M, Kekilli D, Grozinger N, Alker A, Rudolph MG, Schmid G, Schertler GFX, Hennig M, Standfuss J, Dawson RJP. Ligand channel in pharmacologically stabilized rhodopsin. Proc Natl Acad Sci U S A 2018; 115:3640-3645. [PMID: 29555765 PMCID: PMC5889642 DOI: 10.1073/pnas.1718084115] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the degenerative eye disease retinitis pigmentosa (RP), protein misfolding leads to fatal consequences for cell metabolism and rod and cone cell survival. To stop disease progression, a therapeutic approach focuses on stabilizing inherited protein mutants of the G protein-coupled receptor (GPCR) rhodopsin using pharmacological chaperones (PC) that improve receptor folding and trafficking. In this study, we discovered stabilizing nonretinal small molecules by virtual and thermofluor screening and determined the crystal structure of pharmacologically stabilized opsin at 2.4 Å resolution using one of the stabilizing hits (S-RS1). Chemical modification of S-RS1 and further structural analysis revealed the core binding motif of this class of rhodopsin stabilizers bound at the orthosteric binding site. Furthermore, previously unobserved conformational changes are visible at the intradiscal side of the seven-transmembrane helix bundle. A hallmark of this conformation is an open channel connecting the ligand binding site with the membrane and the intradiscal lumen of rod outer segments. Sufficient in size, the passage permits the exchange of hydrophobic ligands such as retinal. The results broaden our understanding of rhodopsin's conformational flexibility and enable therapeutic drug intervention against rhodopsin-related retinitis pigmentosa.
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Affiliation(s)
- Daniel Mattle
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bernd Kuhn
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Johannes Aebi
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Marc Bedoucha
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Demet Kekilli
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Nathalie Grozinger
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Andre Alker
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Markus G Rudolph
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Georg Schmid
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Michael Hennig
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Jörg Standfuss
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland;
| | - Roger J P Dawson
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland;
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13
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Athanasiou D, Aguila M, Opefi CA, South K, Bellingham J, Bevilacqua D, Munro PM, Kanuga N, Mackenzie FE, Dubis AM, Georgiadis A, Graca AB, Pearson RA, Ali RR, Sakami S, Palczewski K, Sherman MY, Reeves PJ, Cheetham ME. Rescue of mutant rhodopsin traffic by metformin-induced AMPK activation accelerates photoreceptor degeneration. Hum Mol Genet 2017; 26:305-319. [PMID: 28065882 PMCID: PMC5351934 DOI: 10.1093/hmg/ddw387] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 01/29/2023] Open
Abstract
Protein misfolding caused by inherited mutations leads to loss of protein function and potentially toxic 'gain of function', such as the dominant P23H rhodopsin mutation that causes retinitis pigmentosa (RP). Here, we tested whether the AMPK activator metformin could affect the P23H rhodopsin synthesis and folding. In cell models, metformin treatment improved P23H rhodopsin folding and traffic. In animal models of P23H RP, metformin treatment successfully enhanced P23H traffic to the rod outer segment, but this led to reduced photoreceptor function and increased photoreceptor cell death. The metformin-rescued P23H rhodopsin was still intrinsically unstable and led to increased structural instability of the rod outer segments. These data suggest that improving the traffic of misfolding rhodopsin mutants is unlikely to be a practical therapy, because of their intrinsic instability and long half-life in the outer segment, but also highlights the potential of altering translation through AMPK to improve protein function in other protein misfolding diseases.
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Affiliation(s)
| | - Monica Aguila
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Chikwado A. Opefi
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
| | - Kieron South
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
| | | | | | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Naheed Kanuga
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | | | - Adam M. Dubis
- Moorfields Eye Hospital NHS Trust, 162 City Road, London, UK
| | | | - Anna B. Graca
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | | | - Robin R. Ali
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Sanae Sakami
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, USA
| | - Michael Y. Sherman
- Department of Biochemistry, Boston University Medical School, Boston, Massachusetts, MA, USA
| | - Philip J. Reeves
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
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14
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Chen Y, Brooks MJ, Gieser L, Swaroop A, Palczewski K. Transcriptome profiling of NIH3T3 cell lines expressing opsin and the P23H opsin mutant identifies candidate drugs for the treatment of retinitis pigmentosa. Pharmacol Res 2016; 115:1-13. [PMID: 27838510 DOI: 10.1016/j.phrs.2016.10.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/18/2016] [Accepted: 10/26/2016] [Indexed: 01/01/2023]
Abstract
Mammalian cells are commonly employed in screening assays to identify active compounds that could potentially affect the progression of different human diseases including retinitis pigmentosa (RP), a class of inherited diseases causing retinal degeneration with compromised vision. Using transcriptome analysis, we compared NIH3T3 cells expressing wildtype (WT) rod opsin with a retinal disease-causing single P23H mutation. Surprisingly, heterologous expression of WT opsin in NIH3T3 cells caused more than a 2-fold change in 783 out of 16,888 protein coding transcripts. The perturbed genes encoded extracellular matrix proteins, growth factors, cytoskeleton proteins, glycoproteins and metalloproteases involved in cell adhesion, morphology and migration. A different set of 347 transcripts was either up- or down-regulated when the P23H mutant opsin was expressed suggesting an altered molecular perturbation compared to WT opsin. Transcriptome perturbations elicited by drug candidates aimed at mitigating the effects of the mutant protein revealed that different drugs targeted distinct molecular pathways that resulted in a similar phenotype selected by a cell-based high-throughput screen. Thus, transcriptome profiling can provide essential information about the therapeutic potential of a candidate drug to restore normal gene expression in pathological conditions.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Matthew J Brooks
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Linn Gieser
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States.
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15
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Alagramam KN, Gopal SR, Geng R, Chen DHC, Nemet I, Lee R, Tian G, Miyagi M, Malagu KF, Lock CJ, Esmieu WRK, Owens AP, Lindsay NA, Ouwehand K, Albertus F, Fischer DF, Bürli RW, MacLeod AM, Harte WE, Palczewski K, Imanishi Y. A small molecule mitigates hearing loss in a mouse model of Usher syndrome III. Nat Chem Biol 2016; 12:444-51. [PMID: 27110679 PMCID: PMC4871731 DOI: 10.1038/nchembio.2069] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 03/08/2016] [Indexed: 12/30/2022]
Abstract
Usher syndrome type III (USH3), characterized by progressive deafness, variable balance disorder and blindness, is caused by destabilizing mutations in the gene encoding the clarin-1 (CLRN1) protein. Here we report a new strategy to mitigate hearing loss associated with a common USH3 mutation CLRN1(N48K) that involves cell-based high-throughput screening of small molecules capable of stabilizing CLRN1(N48K), followed by a secondary screening to eliminate general proteasome inhibitors, and finally an iterative process to optimize structure-activity relationships. This resulted in the identification of BioFocus 844 (BF844). To test the efficacy of BF844, we developed a mouse model that mimicked the progressive hearing loss associated with USH3. BF844 effectively attenuated progressive hearing loss and prevented deafness in this model. Because the CLRN1(N48K) mutation causes both hearing and vision loss, BF844 could in principle prevent both sensory deficiencies in patients with USH3. Moreover, the strategy described here could help identify drugs for other protein-destabilizing monogenic disorders.
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Affiliation(s)
- Kumar N Alagramam
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.,Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, USA.,Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Suhasini R Gopal
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ruishuang Geng
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Daniel H-C Chen
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ina Nemet
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Richard Lee
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Guilian Tian
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Masaru Miyagi
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Karine F Malagu
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Christopher J Lock
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - William R K Esmieu
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Andrew P Owens
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Nicola A Lindsay
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | | | | | | | - Roland W Bürli
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Angus M MacLeod
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - William E Harte
- Office of Translation and Innovation, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yoshikazu Imanishi
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
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16
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Gragg M, Kim TG, Howell S, Park PSH. Wild-type opsin does not aggregate with a misfolded opsin mutant. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1850-9. [PMID: 27117643 DOI: 10.1016/j.bbamem.2016.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/06/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Megan Gragg
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tae Gyun Kim
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Scott Howell
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - P S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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