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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. Proc Natl Acad Sci U S A 2024; 121:e2321430121. [PMID: 38530893 PMCID: PMC10998601 DOI: 10.1073/pnas.2321430121] [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: 12/05/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds- to hours-long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in Caenorhabditis elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change and indicate that the deployment of both transcriptional and nontranscriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA02454
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2
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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570166. [PMID: 38168209 PMCID: PMC10760192 DOI: 10.1101/2023.12.05.570166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds to hours long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in C. elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change, and indicate that the deployment of both transcriptional and non-transcriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454
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3
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Cudia D, Ahoulou EO, Ames JB. Chemical shift assignments of retinal guanylyl cyclase activating protein 5 (GCAP5) with a mutation (R22A) that abolishes dimerization and enhances cyclase activation. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:115-119. [PMID: 37129703 PMCID: PMC10232645 DOI: 10.1007/s12104-023-10129-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/19/2023] [Indexed: 05/03/2023]
Abstract
Retinal membrane guanylyl cyclases (RetGCs) in vertebrate rod and cone photoreceptors are activated by a family of neuronal Ca2+ sensor proteins called guanylyl cyclase activating proteins (GCAP1-7). GCAP5 from zebrafish photoreceptors binds to RetGC and confers Ca2+/Fe2+-dependent regulation of RetGC enzymatic activity that promotes the recovery phase of visual phototransduction. We report NMR chemical shift assignments of GCAP5 with a R22A mutation (called GCAP5R22A) that abolishes protein dimerization and activates RetGC with 3-fold higher activity than that of wild type GCAP5 (BMRB No. 51,783).
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Affiliation(s)
- Diana Cudia
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Effibe O Ahoulou
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, 95616, USA.
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4
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Gesemann M, Neuhauss SCF. Evolution of visual guanylyl cyclases and their activating proteins with respect to clade and species-specific visual system adaptation. Front Mol Neurosci 2023; 16:1131093. [PMID: 37008786 PMCID: PMC10061024 DOI: 10.3389/fnmol.2023.1131093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
Membrane guanylyl cyclase receptors are important regulators of local cGMP production, critically influencing cell growth and differentiation as well as ion transport, blood pressure and calcium feedback of vertebrate phototransduction. Currently, seven different subtypes of membrane guanylyl cyclase receptors have been characterized. These receptors have tissue specific expression and are activated either by small extracellular ligands, changing CO2 concentrations or, in the case of visual guanylyl cyclases, intracellularly interacting Ca2+-dependent activating proteins. In this report, we focus on the visual guanylyl cyclase receptors (GCs) GC-E (gucy2d/e) and GC-F (gucy2f) and their activating proteins (GCAP1/2/3; guca1a/b/c). While gucy2d/e has been detected in all analyzed vertebrates, GC-F receptors are missing in several clades (reptiles, birds, and marsupials) and/or individual species. Interestingly, the absence of GC-F in highly visual sauropsida species with up to 4 different cone-opsins is compensated by an increased number of guanylyl cyclase activating proteins, whereas in nocturnal or visually impaired species with reduced spectral sensitivity it is consolidated by the parallel inactivation of these activators. In mammals, the presence of GC-E and GC-F is accompanied by the expression of one to three GCAPs, whereas in lizards and birds, up to five different GCAPs are regulating the activity of the single GC-E visual membrane receptor. In several nearly blind species, a single GC-E enzyme is often accompanied by a single variant of GCAP, suggesting that one cyclase and one activating protein are both sufficient and required for conferring the basic detection of light.
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5
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Avesani A, Marino V, Zanzoni S, Koch KW, Dell'Orco D. Molecular properties of human guanylate cyclase-activating protein 2 (GCAP2) and its retinal dystrophy-associated variant G157R. J Biol Chem 2021; 296:100619. [PMID: 33812995 PMCID: PMC8113879 DOI: 10.1016/j.jbc.2021.100619] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 12/31/2022] Open
Abstract
In murine and bovine photoreceptors, guanylate cyclase-activating protein 2 (GCAP2) activates retinal guanylate cyclases (GCs) at low Ca2+ levels, thus contributing to the Ca2+/cGMP negative feedback on the cyclase together with its paralog guanylate cyclase-activating protein 1, which has the same function but different Ca2+ sensitivity. In humans, a GCAP2 missense mutation (G157R) has been associated with inherited retinal degeneration (IRD) via an unknown molecular mechanism. Here, we characterized the biochemical properties of human GCAP2 and the G157R variant, focusing on its dimerization and the Ca2+/Mg2+-binding processes in the presence or absence of N-terminal myristoylation. We found that human GCAP2 and its bovine/murine orthologs significantly differ in terms of oligomeric properties, cation binding, and GC regulation. Myristoylated GCAP2 endothermically binds up to 3 Mg2+ with high affinity and forms a compact dimer that may reversibly dissociate in the presence of Ca2+. Conversely, nonmyristoylated GCAP2 does not bind Mg2+ over the physiological range and remains as a monomer in the absence of Ca2+. Both myristoylated and nonmyristoylated GCAP2 bind Ca2+ with high affinity. At odds with guanylate cyclase-activating protein 1 and independently of myristoylation, human GCAP2 does not significantly activate retinal GC1 in a Ca2+-dependent fashion. The IRD-associated G157R variant is characterized by a partly misfolded, molten globule-like conformation with reduced affinity for cations and prone to form aggregates, likely mediated by hydrophobic interactions. Our findings suggest that GCAP2 might be mostly implicated in processes other than phototransduction in human photoreceptors and suggest a possible molecular mechanism for G157R-associated IRD.
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Affiliation(s)
- Anna Avesani
- Department of Neurosciences, Biomedicine and Movement Sciences, Biological Chemistry Section, University of Verona, Verona, Italy
| | - Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Biological Chemistry Section, University of Verona, Verona, Italy
| | - Serena Zanzoni
- Centro Piattaforme Tecnologiche, University of Verona, Verona, Italy
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Division of Biochemistry, University of Oldenburg, Oldenburg, Germany
| | - Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Biological Chemistry Section, University of Verona, Verona, Italy.
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6
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Regulation of retinal membrane guanylyl cyclase (RetGC) by negative calcium feedback and RD3 protein. Pflugers Arch 2021; 473:1393-1410. [PMID: 33537894 PMCID: PMC8329130 DOI: 10.1007/s00424-021-02523-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 11/07/2022]
Abstract
This article presents a brief overview of the main biochemical and cellular processes involved in regulation of cyclic GMP production in photoreceptors. The main focus is on how the fluctuations of free calcium concentrations in photoreceptors between light and dark regulate the activity of retinal membrane guanylyl cyclase (RetGC) via calcium sensor proteins. The emphasis of the review is on the structure of RetGC and guanylyl cyclase activating proteins (GCAPs) in relation to their functional role in photoreceptors and congenital diseases of photoreceptors. In addition to that, the structure and function of retinal degeneration-3 protein (RD3), which regulates RetGC in a calcium-independent manner, is discussed in detail in connections with its role in photoreceptor biology and inherited retinal blindness.
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7
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Fortenbach C, Peinado Allina G, Shores CM, Karlen SJ, Miller EB, Bishop H, Trimmer JS, Burns ME, Pugh EN. Loss of the K+ channel Kv2.1 greatly reduces outward dark current and causes ionic dysregulation and degeneration in rod photoreceptors. J Gen Physiol 2021; 153:211728. [PMID: 33502442 PMCID: PMC7845921 DOI: 10.1085/jgp.202012687] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/25/2020] [Accepted: 11/25/2020] [Indexed: 12/21/2022] Open
Abstract
Vertebrate retinal photoreceptors signal light by suppressing a circulating “dark current” that maintains their relative depolarization in the dark. This dark current is composed of an inward current through CNG channels and NCKX transporters in the outer segment that is balanced by outward current exiting principally from the inner segment. It has been hypothesized that Kv2.1 channels carry a predominant fraction of the outward current in rods. We examined this hypothesis by comparing whole cell, suction electrode, and electroretinographic recordings from Kv2.1 knockout (Kv2.1−/−) and wild-type (WT) mouse rods. Single cell recordings revealed flash responses with unusual kinetics, and reduced dark currents that were quantitatively consistent with the measured depolarization of the membrane resting potential in the dark. A two-compartment (outer and inner segment) physiological model based on known ionic mechanisms revealed that the abnormal Kv2.1−/− rod photoresponses arise principally from the voltage dependencies of the known conductances and the NCKX exchanger, and a highly elevated fraction of inward current carried by Ca2+ through CNG channels due to the aberrant depolarization. Kv2.1−/− rods had shorter outer segments than WT and dysmorphic mitochondria in their inner segments. Optical coherence tomography of knockout animals demonstrated a slow photoreceptor degeneration over a period of 6 mo. Overall, these findings reveal that Kv2.1 channels carry 70–80% of the non-NKX outward dark current of the mouse rod, and that the depolarization caused by the loss of Kv2.1 results in elevated Ca2+ influx through CNG channels and elevated free intracellular Ca2+, leading to progressive degeneration.
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Affiliation(s)
| | | | - Camilla M Shores
- Center for Neuroscience, University of California, Davis, Davis, CA
| | - Sarah J Karlen
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, CA
| | - Eric B Miller
- Center for Neuroscience, University of California, Davis, Davis, CA
| | - Hannah Bishop
- Center for Neuroscience, University of California, Davis, Davis, CA.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA
| | - James S Trimmer
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA.,Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Marie E Burns
- Center for Neuroscience, University of California, Davis, Davis, CA.,Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA.,Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, CA
| | - Edward N Pugh
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA.,Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA.,Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, CA
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8
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Vladimirov VI, Baksheeva VE, Mikhailova IV, Ismailov RG, Litus EA, Tikhomirova NK, Nazipova AA, Permyakov SE, Zernii EY, Zinchenko DV. A Novel Approach to Bacterial Expression and Purification of Myristoylated Forms of Neuronal Calcium Sensor Proteins. Biomolecules 2020; 10:biom10071025. [PMID: 32664359 PMCID: PMC7407513 DOI: 10.3390/biom10071025] [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: 06/23/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 11/18/2022] Open
Abstract
N-terminal myristoylation is a common co-and post-translational modification of numerous eukaryotic and viral proteins, which affects their interaction with lipids and partner proteins, thereby modulating various cellular processes. Among those are neuronal calcium sensor (NCS) proteins, mediating transduction of calcium signals in a wide range of regulatory cascades, including reception, neurotransmission, neuronal growth and survival. The details of NCSs functioning are of special interest due to their involvement in the progression of ophthalmological and neurodegenerative diseases and their role in cancer. The well-established procedures for preparation of native-like myristoylated forms of recombinant NCSs via their bacterial co-expression with N-myristoyl transferase from Saccharomyces cerevisiae often yield a mixture of the myristoylated and non-myristoylated forms. Here, we report a novel approach to preparation of several NCSs, including recoverin, GCAP1, GCAP2, neurocalcin δ and NCS-1, ensuring their nearly complete N-myristoylation. The optimized bacterial expression and myristoylation of the NCSs is followed by a set of procedures for separation of their myristoylated and non-myristoylated forms using a combination of hydrophobic interaction chromatography steps. We demonstrate that the refolded and further purified myristoylated NCS-1 maintains its Са2+-binding ability and stability of tertiary structure. The developed approach is generally suited for preparation of other myristoylated proteins.
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Affiliation(s)
- Vasiliy I. Vladimirov
- Laboratory of pharmacokinetics, Department of Biological Testing, Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Puschino, Pushchino, 142290 Moscow Region, Russia; (V.I.V.); (I.V.M.)
| | - Viktoriia E. Baksheeva
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (N.K.T.); (E.Y.Z.)
| | - Irina V. Mikhailova
- Laboratory of pharmacokinetics, Department of Biological Testing, Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Puschino, Pushchino, 142290 Moscow Region, Russia; (V.I.V.); (I.V.M.)
- Faculty of BioMedPharmTechnological, Pushchino State Institute of Natural Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Ramis G. Ismailov
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Pushchino, 142290 Moscow Region, Russia; (R.G.I.); (E.A.L.); (A.A.N.); (S.E.P.)
| | - Ekaterina A. Litus
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Pushchino, 142290 Moscow Region, Russia; (R.G.I.); (E.A.L.); (A.A.N.); (S.E.P.)
| | - Natalia K. Tikhomirova
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (N.K.T.); (E.Y.Z.)
| | - Aliya A. Nazipova
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Pushchino, 142290 Moscow Region, Russia; (R.G.I.); (E.A.L.); (A.A.N.); (S.E.P.)
| | - Sergei E. Permyakov
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Pushchino, 142290 Moscow Region, Russia; (R.G.I.); (E.A.L.); (A.A.N.); (S.E.P.)
| | - Evgeni Yu. Zernii
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (N.K.T.); (E.Y.Z.)
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Dmitry V. Zinchenko
- Laboratory of pharmacokinetics, Department of Biological Testing, Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Puschino, Pushchino, 142290 Moscow Region, Russia; (V.I.V.); (I.V.M.)
- Correspondence:
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9
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Constitutive Activation of Guanylate Cyclase by the G86R GCAP1 Variant Is Due to "Locking" Cation-π Interactions that Impair the Activator-to-Inhibitor Structural Transition. Int J Mol Sci 2020; 21:ijms21030752. [PMID: 31979372 PMCID: PMC7037459 DOI: 10.3390/ijms21030752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 02/06/2023] Open
Abstract
Guanylate Cyclase activating protein 1 (GCAP1) mediates the Ca2+-dependent regulation of the retinal Guanylate Cyclase (GC) in photoreceptors, acting as a target inhibitor at high [Ca2+] and as an activator at low [Ca2+]. Recently, a novel missense mutation (G86R) was found in GUCA1A, the gene encoding for GCAP1, in patients diagnosed with cone-rod dystrophy. The G86R substitution was found to affect the flexibility of the hinge region connecting the N- and C-domains of GCAP1, resulting in decreased Ca2+-sensitivity and abnormally enhanced affinity for GC. Based on a structural model of GCAP1, here, we tested the hypothesis of a cation-π interaction between the positively charged R86 and the aromatic W94 as the main mechanism underlying the impaired activator-to-inhibitor conformational change. W94 was mutated to F or L, thus, resulting in the double mutants G86R+W94L/F. The double mutants showed minor structural and stability changes with respect to the single G86R mutant, as well as lower affinity for both Mg2+ and Ca2+, moreover, substitutions of W94 abolished "phase II" in Ca2+-titrations followed by intrinsic fluorescence. Interestingly, the presence of an aromatic residue in position 94 significantly increased the aggregation propensity of Ca2+-loaded GCAP1 variants. Finally, atomistic simulations of all GCAP1 variants in the presence of Ca2+ supported the presence of two cation-π interactions involving R86, which was found to act as a bridge between W94 and W21, thus, locking the hinge region in an activator-like conformation and resulting in the constitutive activation of the target under physiological conditions.
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10
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Lamb TD. Evolution of the genes mediating phototransduction in rod and cone photoreceptors. Prog Retin Eye Res 2019; 76:100823. [PMID: 31790748 DOI: 10.1016/j.preteyeres.2019.100823] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 12/28/2022]
Abstract
This paper reviews current knowledge of the evolution of the multiple genes encoding proteins that mediate the process of phototransduction in rod and cone photoreceptors of vertebrates. The approach primarily involves molecular phylogenetic analysis of phototransduction protein sequences, combined with analysis of the syntenic arrangement of the genes. At least 35 of these phototransduction genes appear to reside on no more than five paralogons - paralogous regions that each arose from a common ancestral region. Furthermore, it appears that such paralogs arose through quadruplication during the two rounds of genome duplication (2R WGD) that occurred in a chordate ancestor prior to the vertebrate radiation, probably around 600 millions years ago. For several components of the phototransduction cascade, it is shown that distinct isoforms already existed prior to WGD, with the likely implication that separate classes of scotopic and photopic photoreceptor cells had already evolved by that stage. The subsequent quadruplication of the entire genome then permitted the refinement of multiple distinct protein isoforms in rods and cones. A unified picture of the likely pattern and approximate timing of all the important gene duplications is synthesised, and the implications for our understanding of the evolution of rod and cone phototransduction are presented.
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Affiliation(s)
- Trevor D Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, ACT, 2601, Australia.
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11
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Burgoyne RD, Helassa N, McCue HV, Haynes LP. Calcium Sensors in Neuronal Function and Dysfunction. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035154. [PMID: 30833454 DOI: 10.1101/cshperspect.a035154] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcium signaling in neurons as in other cell types can lead to varied changes in cellular function. Neuronal Ca2+ signaling processes have also become adapted to modulate the function of specific pathways over a wide variety of time domains and these can have effects on, for example, axon outgrowth, neuronal survival, and changes in synaptic strength. Ca2+ also plays a key role in synapses as the trigger for fast neurotransmitter release. Given its physiological importance, abnormalities in neuronal Ca2+ signaling potentially underlie many different neurological and neurodegenerative diseases. The mechanisms by which changes in intracellular Ca2+ concentration in neurons can bring about diverse responses is underpinned by the roles of ubiquitous or specialized neuronal Ca2+ sensors. It has been established that synaptotagmins have key functions in neurotransmitter release, and, in addition to calmodulin, other families of EF-hand-containing neuronal Ca2+ sensors, including the neuronal calcium sensor (NCS) and the calcium-binding protein (CaBP) families, play important physiological roles in neuronal Ca2+ signaling. It has become increasingly apparent that these various Ca2+ sensors may also be crucial for aspects of neuronal dysfunction and disease either indirectly or directly as a direct consequence of genetic variation or mutations. An understanding of the molecular basis for the regulation of the targets of the Ca2+ sensors and the physiological roles of each protein in identified neurons may contribute to future approaches to the development of treatments for a variety of human neuronal disorders.
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Affiliation(s)
- Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Nordine Helassa
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Hannah V McCue
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Lee P Haynes
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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12
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Cudia D, Ames JB. Chemical shift assignments of retinal guanylyl cyclase activating protein 5 (GCAP5). BIOMOLECULAR NMR ASSIGNMENTS 2019; 13:201-205. [PMID: 30706384 PMCID: PMC6440817 DOI: 10.1007/s12104-019-09877-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/28/2019] [Indexed: 05/20/2023]
Abstract
Retinal membrane guanylyl cyclase (RetGC) in photoreceptor rod and cone cells is regulated by a family of guanylyl cyclase activating proteins (GCAP1-7). GCAP5 is expressed in zebrafish photoreceptors and promotes Ca2+-dependent regulation of RetGC enzymatic activity that regulates visual phototransduction. We report NMR chemical shift assignments of the Ca2+-free activator form of GCAP5 (BMRB No. 27705).
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Affiliation(s)
- Diana Cudia
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, 95616, USA.
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13
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Peshenko IV, Yu Q, Lim S, Cudia D, Dizhoor AM, Ames JB. Retinal degeneration 3 (RD3) protein, a retinal guanylyl cyclase regulator, forms a monomeric and elongated four-helix bundle. J Biol Chem 2019; 294:2318-2328. [PMID: 30559291 PMCID: PMC6378972 DOI: 10.1074/jbc.ra118.006106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/07/2018] [Indexed: 12/20/2022] Open
Abstract
Retinal degeneration 3 (RD3) protein promotes accumulation of retinal membrane guanylyl cyclase (RetGC) in the photoreceptor outer segment and suppresses RetGC activation by guanylyl cyclase-activating proteins (GCAPs). Mutations truncating RD3 cause severe congenital blindness by preventing the inhibitory binding of RD3 to the cyclase. The high propensity of RD3 to aggregate in solution has prevented structural analysis. Here, we produced a highly soluble variant of human RD3 (residues 18-160) that is monomeric and can still bind and negatively regulate RetGC. The NMR solution structure of RD3 revealed an elongated backbone structure (70 Å long and 30 Å wide) consisting of a four-helix bundle with a long unstructured loop between helices 1 and 2. The structure reveals that RD3 residues previously implicated in the RetGC binding map to a localized and contiguous area on the structure, involving a loop between helices 2 and 3 and adjacent parts of helices 3 and 4. The NMR structure of RD3 was validated by mutagenesis. Introducing Trp85 or Phe29 to replace Cys or Leu, respectively, disrupts packing in the hydrophobic core and lowers RD3's apparent affinity for RetGC1. Introducing a positive charge at the interface (Glu32 to Lys) also lowered the affinity. Conversely, introducing Val in place of Cys93 stabilized the hydrophobic core and increased the RD3 affinity for the cyclase. The NMR structure of RD3 presented here provides a structural basis for elucidating RD3-RetGC interactions relevant for normal vision or blindness.
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Affiliation(s)
- Igor V Peshenko
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027 and
| | - Qinhong Yu
- the Department of Chemistry, University of California, Davis, California 95616
| | - Sunghyuk Lim
- the Department of Chemistry, University of California, Davis, California 95616
| | - Diana Cudia
- the Department of Chemistry, University of California, Davis, California 95616
| | - Alexander M Dizhoor
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027 and
| | - James B Ames
- the Department of Chemistry, University of California, Davis, California 95616
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14
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Peshenko IV, Cideciyan AV, Sumaroka A, Olshevskaya EV, Scholten A, Abbas S, Koch KW, Jacobson SG, Dizhoor AM. A G86R mutation in the calcium-sensor protein GCAP1 alters regulation of retinal guanylyl cyclase and causes dominant cone-rod degeneration. J Biol Chem 2019; 294:3476-3488. [PMID: 30622141 DOI: 10.1074/jbc.ra118.006180] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/04/2019] [Indexed: 11/06/2022] Open
Abstract
The guanylyl cyclase-activating protein, GCAP1, activates photoreceptor membrane guanylyl cyclase (RetGC) in the light, when free Ca2+ concentrations decline, and decelerates the cyclase in the dark, when Ca2+ concentrations rise. Here, we report a novel mutation, G86R, in the GCAP1 (GUCA1A) gene in a family with a dominant retinopathy. The G86R substitution in a "hinge" region connecting EF-hand domains 2 and 3 in GCAP1 strongly interfered with its Ca2+-dependent activator-to-inhibitor conformational transition. The G86R-GCAP1 variant activated RetGC at low Ca2+ concentrations with higher affinity than did the WT GCAP1, but failed to decelerate the cyclase at the Ca2+ concentrations characteristic of dark-adapted photoreceptors. Ca2+-dependent increase in Trp94 fluorescence, indicative of the GCAP1 transition to its RetGC inhibiting state, was suppressed and shifted to a higher Ca2+ range. Conformational changes in G86R GCAP1 detectable by isothermal titration calorimetry (ITC) also became less sensitive to Ca2+, and the dose dependence of the G86R GCAP1-RetGC1 complex inhibition by retinal degeneration 3 (RD3) protein was shifted toward higher than normal concentrations. Our results indicate that the flexibility of the hinge region between EF-hands 2 and 3 is required for placing GCAP1-regulated Ca2+ sensitivity of the cyclase within the physiological range of intracellular Ca2+ at the expense of reducing GCAP1 affinity for the target enzyme. The disease-linked mutation of the hinge Gly86, leading to abnormally high affinity for the target enzyme and reduced Ca2+ sensitivity of GCAP1, is predicted to abnormally elevate cGMP production and Ca2+ influx in photoreceptors in the dark.
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Affiliation(s)
- Igor V Peshenko
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
| | - Artur V Cideciyan
- the Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Alexander Sumaroka
- the Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Elena V Olshevskaya
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
| | - Alexander Scholten
- the Department of Neuroscience, University of Oldenburg, Oldenburg D-26129, Germany
| | - Seher Abbas
- the Department of Neuroscience, University of Oldenburg, Oldenburg D-26129, Germany
| | - Karl-Wilhelm Koch
- the Department of Neuroscience, University of Oldenburg, Oldenburg D-26129, Germany
| | - Samuel G Jacobson
- the Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Alexander M Dizhoor
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027,
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15
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Lamb TD, Hunt DM. Evolution of the calcium feedback steps of vertebrate phototransduction. Open Biol 2018; 8:180119. [PMID: 30257895 PMCID: PMC6170504 DOI: 10.1098/rsob.180119] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/29/2018] [Indexed: 01/11/2023] Open
Abstract
We examined the genes encoding the proteins that mediate the Ca-feedback regulatory system in vertebrate rod and cone phototransduction. These proteins comprise four families: recoverin/visinin, the guanylyl cyclase activating proteins (GCAPs), the guanylyl cyclases (GCs) and the sodium/calcium-potassium exchangers (NCKXs). We identified a paralogon containing at least 36 phototransduction genes from at least fourteen families, including all four of the families involved in the Ca-feedback loop (recoverin/visinin, GCAPs, GCs and NCKXs). By combining analyses of gene synteny with analyses of the molecular phylogeny for each of these four families of genes for Ca-feedback regulation, we have established the likely pattern of gene duplications and losses underlying the expansion of isoforms, both before and during the two rounds of whole-genome duplication (2R WGD) that occurred in early vertebrate evolution. Furthermore, by combining our results with earlier evidence on the timing of duplication of the visual G-protein receptor kinase genes, we propose that specialization of proto-vertebrate photoreceptor cells for operation at high and low light intensities preceded the emergence of rhodopsin, which occurred during 2R WGD.
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Affiliation(s)
- Trevor D Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Australian Capital Territory 2600, Australia
| | - David M Hunt
- Centre for Ophthalmology and Visual Science, The Lions Eye Institute, The University of Western Australia, Western Australia 6009, Australia
- School of Biological Sciences, The University of Western Australia, Western Australia 6009, Australia
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16
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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17
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López-Begines S, Plana-Bonamaisó A, Méndez A. Molecular determinants of Guanylate Cyclase Activating Protein subcellular distribution in photoreceptor cells of the retina. Sci Rep 2018; 8:2903. [PMID: 29440717 PMCID: PMC5811540 DOI: 10.1038/s41598-018-20893-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/26/2018] [Indexed: 11/10/2022] Open
Abstract
Retinal guanylate cyclase (RetGC) and guanylate cyclase activating proteins (GCAPs) play an important role during the light response in photoreceptor cells. Mutations in these proteins are linked to distinct forms of blindness. RetGC and GCAPs exert their role at the ciliary outer segment where phototransduction takes place. We investigated the mechanisms governing GCAP1 and GCAP2 distribution to rod outer segments by expressing selected GCAP1 and GCAP2 mutants as transient transgenes in the rods of GCAP1/2 double knockout mice. We show that precluding GCAP1 direct binding to RetGC (K23D/GCAP1) prevented its distribution to rod outer segments, while preventing GCAP1 activation of RetGC post-binding (W94A/GCAP1) did not. We infer that GCAP1 translocation to the outer segment strongly depends on GCAP1 binding affinity for RetGC, which points to GCAP1 requirement to bind to RetGC to be transported. We gain further insight into the distinctive regulatory steps of GCAP2 distribution, by showing that a phosphomimic at position 201 is sufficient to retain GCAP2 at proximal compartments; and that the bovine equivalent to blindness-causative mutation G157R/GCAP2 results in enhanced phosphorylation in vitro and significant retention at the inner segment in vivo, as likely contributing factors to the pathophysiology.
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Affiliation(s)
- Santiago López-Begines
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain
| | - Anna Plana-Bonamaisó
- Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain
| | - Ana Méndez
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain. .,Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain.
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18
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The extraordinary AFD thermosensor of C. elegans. Pflugers Arch 2017; 470:839-849. [PMID: 29218454 DOI: 10.1007/s00424-017-2089-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
The nematode C. elegans exhibits complex thermal experience-dependent navigation behaviors in response to environmental temperature changes of as little as 0.01°C over a > 10°C temperature range. The remarkable thermosensory abilities of this animal are mediated primarily via the single pair of AFD sensory neurons in its head. In this review, we describe the contributions of AFD to thermosensory behaviors and temperature-dependent regulation of organismal physiology. We also discuss the mechanisms that enable this neuron type to adapt to recent temperature experience and to exhibit extraordinary thermosensitivity over a wide dynamic range.
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19
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Kawasaki H, Kretsinger RH. Structural and functional diversity of EF-hand proteins: Evolutionary perspectives. Protein Sci 2017; 26:1898-1920. [PMID: 28707401 PMCID: PMC5606533 DOI: 10.1002/pro.3233] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/07/2017] [Accepted: 07/07/2017] [Indexed: 01/02/2023]
Abstract
We have classified 865 sequences of EF-hand proteins from five proteomes into 156 subfamilies. These subfamilies were put into six groups. Evolutionary relationships among subfamilies and groups were analyzed from the inferred ancestral sequence for each subfamily. CTER, CPV, and PEF groups arose from a common EF-lobe (pair of adjacent EF-hands). They have two or more EF-lobes; the relative positions of their EF-lobes differ from each other. Comparisons of the ancestral sequences and the inferred structures of the EF-lobes of these groups indicate that the mutual positions of EF-lobes were established soon after divergence of an EF-lobe for each group and before the duplication and fusion of EF-lobe gene(s). These ancestral sequences reveal that some subfamilies in low similarity and isolated groups did not evolve from the EF-lobe precursor, even if their conformations are similar to the canonical EF-hand. This is an example of convergent evolution.
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Affiliation(s)
- Hiroshi Kawasaki
- Department of Medical Life ScienceGraduate School of Medical Life Science, Yokohama City UniversityYokohamaKanagawa230‐0045Japan
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20
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Sharma RK, Duda T, Makino CL. Integrative Signaling Networks of Membrane Guanylate Cyclases: Biochemistry and Physiology. Front Mol Neurosci 2016; 9:83. [PMID: 27695398 PMCID: PMC5023690 DOI: 10.3389/fnmol.2016.00083] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/29/2016] [Indexed: 12/24/2022] Open
Abstract
This monograph presents a historical perspective of cornerstone developments on the biochemistry and physiology of mammalian membrane guanylate cyclases (MGCs), highlighting contributions made by the authors and their collaborators. Upon resolution of early contentious studies, cyclic GMP emerged alongside cyclic AMP, as an important intracellular second messenger for hormonal signaling. However, the two signaling pathways differ in significant ways. In the cyclic AMP pathway, hormone binding to a G protein coupled receptor leads to stimulation or inhibition of an adenylate cyclase, whereas the cyclic GMP pathway dispenses with intermediaries; hormone binds to an MGC to affect its activity. Although the cyclic GMP pathway is direct, it is by no means simple. The modular design of the molecule incorporates regulation by ATP binding and phosphorylation. MGCs can form complexes with Ca2+-sensing subunits that either increase or decrease cyclic GMP synthesis, depending on subunit identity. In some systems, co-expression of two Ca2+ sensors, GCAP1 and S100B with ROS-GC1 confers bimodal signaling marked by increases in cyclic GMP synthesis when intracellular Ca2+ concentration rises or falls. Some MGCs monitor or are modulated by carbon dioxide via its conversion to bicarbonate. One MGC even functions as a thermosensor as well as a chemosensor; activity reaches a maximum with a mild drop in temperature. The complexity afforded by these multiple limbs of operation enables MGC networks to perform transductions traditionally reserved for G protein coupled receptors and Transient Receptor Potential (TRP) ion channels and to serve a diverse array of functions, including control over cardiac vasculature, smooth muscle relaxation, blood pressure regulation, cellular growth, sensory transductions, neural plasticity and memory.
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Affiliation(s)
- Rameshwar K Sharma
- The Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University Elkins Park, PA, USA
| | - Teresa Duda
- The Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University Elkins Park, PA, USA
| | - Clint L Makino
- Department of Physiology and Biophysics, Boston University School of Medicine Boston, MA, USA
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21
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Sildenafil (Viagra(®)) prevents and restores LPS-induced inflammation in astrocytes. Neurosci Lett 2016; 630:59-65. [PMID: 27466020 DOI: 10.1016/j.neulet.2016.07.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 07/15/2016] [Accepted: 07/16/2016] [Indexed: 01/25/2023]
Abstract
Astrocytes are effectively involved in the pathophysiological processes in the central nervous system (CNS) and may contribute to or protect against development of inflammatory and degenerative diseases. Sildenafil is a potent and selective phosphodiesterase-5 (PDE-5) inhibitor, which induces cyclic GMP accumulation. However, the mechanisms of actions on glial cells are not clear. The aim of the present work is to evaluate the role of sildenafil in lipopolysaccharide (LPS)-stimulated astrocytes. The cytoskeleton integrity and Ca(2+) waves were assessed as indicators of inflammatory state. Two main groups were done: (A) one prevention and (B) one restoration. Each of these groups: A1: control; A2: LPS for 24h; A3: sildenafil 1 or 10μM for 4h and then sildenafil 1 or 10μM+LPS for 24h. B1: control; B2: LPS for 24h; B3: LPS for 24h and then LPS+sildenafil 1 or 10μM for 24h. Cytoskeleton integrity was analyzed through GFAP immunolabeling and actin labeling with an Alexa 488-conjugated phalloidin probe. Calcium responses were assessed through a Ca(2+)-sensitive fluorophore Fura-2/AM. The results show that both preventive and restorative treatments with sildenafil (in both concentrations) reduced the Ca(2+) responses in intensity and induced a more organized actin fiber pattern, compared to LPS treated cells. This work demonstrated for the first time that astrocytes are a key part of the sildenafil protective effects in the CNS.
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22
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Permyakov EA, Uversky VN, Permyakov SE. Interleukin-11: A Multifunctional Cytokine with Intrinsically Disordered Regions. Cell Biochem Biophys 2016; 74:285-96. [DOI: 10.1007/s12013-016-0752-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/13/2016] [Indexed: 12/14/2022]
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23
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Receptor-type Guanylyl Cyclases Confer Thermosensory Responses in C. elegans. Neuron 2016; 90:235-44. [PMID: 27041501 DOI: 10.1016/j.neuron.2016.03.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/25/2016] [Accepted: 02/26/2016] [Indexed: 01/03/2023]
Abstract
Thermosensation is critical for optimal regulation of physiology and behavior. C. elegans acclimates to its cultivation temperature (Tc) and exhibits thermosensitive behaviors at temperatures relative to Tc. These behaviors are mediated primarily by the AFD sensory neurons, which are extraordinarily thermosensitive and respond to thermal fluctuations at temperatures above a Tc-determined threshold. Although cGMP signaling is necessary for thermotransduction, the thermosensors in AFD are unknown. We show that AFD-specific receptor guanylyl cyclases (rGCs) are instructive for thermosensation. In addition to being necessary for thermotransduction, ectopic expression of these rGCs confers highly temperature-dependent responses onto diverse cell types. We find that the temperature response threshold is determined by the rGC and cellular context, and that multiple domains contribute to their thermosensory properties. Identification of thermosensory rGCs in C. elegans provides insight into mechanisms of thermosensation and thermal acclimation and suggests that rGCs may represent a new family of molecular thermosensors.
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24
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Kazakov AS, Sokolov AS, Vologzhannikova AA, Permyakova ME, Khorn PA, Ismailov RG, Denessiouk KA, Denesyuk AI, Rastrygina VA, Baksheeva VE, Zernii EY, Zinchenko DV, Glazatov VV, Uversky VN, Mirzabekov TA, Permyakov EA, Permyakov SE. Interleukin-11 binds specific EF-hand proteins via their conserved structural motifs. J Biomol Struct Dyn 2016; 35:78-91. [PMID: 26726132 DOI: 10.1080/07391102.2015.1132392] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Interleukin-11 (IL-11) is a hematopoietic cytokine engaged in numerous biological processes and validated as a target for treatment of various cancers. IL-11 contains intrinsically disordered regions that might recognize multiple targets. Recently we found that aside from IL-11RA and gp130 receptors, IL-11 interacts with calcium sensor protein S100P. Strict calcium dependence of this interaction suggests a possibility of IL-11 interaction with other calcium sensor proteins. Here we probed specificity of IL-11 to calcium-binding proteins of various types: calcium sensors of the EF-hand family (calmodulin, S100B and neuronal calcium sensors: recoverin, NCS-1, GCAP-1, GCAP-2), calcium buffers of the EF-hand family (S100G, oncomodulin), and a non-EF-hand calcium buffer (α-lactalbumin). A specific subset of the calcium sensor proteins (calmodulin, S100B, NCS-1, GCAP-1/2) exhibits metal-dependent binding of IL-11 with dissociation constants of 1-19 μM. These proteins share several amino acid residues belonging to conservative structural motifs of the EF-hand proteins, 'black' and 'gray' clusters. Replacements of the respective S100P residues by alanine drastically decrease its affinity to IL-11, suggesting their involvement into the association process. Secondary structure and accessibility of the hinge region of the EF-hand proteins studied are predicted to control specificity and selectivity of their binding to IL-11. The IL-11 interaction with the EF-hand proteins is expected to occur under numerous pathological conditions, accompanied by disintegration of plasma membrane and efflux of cellular components into the extracellular milieu.
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Affiliation(s)
- Alexei S Kazakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Andrei S Sokolov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Alisa A Vologzhannikova
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Maria E Permyakova
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Polina A Khorn
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Ramis G Ismailov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Konstantin A Denessiouk
- b Faculty of Science and Engineering , Åbo Akademi University , Biskopsgatan 8, Åbo 20500 , Finland
| | - Alexander I Denesyuk
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia.,b Faculty of Science and Engineering , Åbo Akademi University , Biskopsgatan 8, Åbo 20500 , Finland
| | - Victoria A Rastrygina
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Viktoriia E Baksheeva
- c Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University , Leninskye Gory, House 1, Building 40, Moscow 119992 , Russia
| | - Evgeni Yu Zernii
- c Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University , Leninskye Gory, House 1, Building 40, Moscow 119992 , Russia
| | - Dmitry V Zinchenko
- d Branch of Shemyakin and Ovchinnikov , Institute of Bioorganic Chemistry of the Russian Academy of Sciences , Institutskaya str. 6, Pushchino, Moscow Region 142290 , Russia
| | | | - Vladimir N Uversky
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia.,f Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , FL 33612 , USA
| | - Tajib A Mirzabekov
- g Antherix , Institutskaya str. 7, Pushchino, Moscow Region 142290 , Russia.,h Biomirex Inc. , 304 Pleasant Street, Watertown , MA 02472 , USA
| | - Eugene A Permyakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Sergei E Permyakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
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25
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Bidlingmaier S, Ha K, Lee NK, Su Y, Liu B. Proteome-wide Identification of Novel Ceramide-binding Proteins by Yeast Surface cDNA Display and Deep Sequencing. Mol Cell Proteomics 2016; 15:1232-45. [PMID: 26729710 DOI: 10.1074/mcp.m115.055954] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 11/06/2022] Open
Abstract
Although the bioactive sphingolipid ceramide is an important cell signaling molecule, relatively few direct ceramide-interacting proteins are known. We used an approach combining yeast surface cDNA display and deep sequencing technology to identify novel proteins binding directly to ceramide. We identified 234 candidate ceramide-binding protein fragments and validated binding for 20. Most (17) bound selectively to ceramide, although a few (3) bound to other lipids as well. Several novel ceramide-binding domains were discovered, including the EF-hand calcium-binding motif, the heat shock chaperonin-binding motif STI1, the SCP2 sterol-binding domain, and the tetratricopeptide repeat region motif. Interestingly, four of the verified ceramide-binding proteins (HPCA, HPCAL1, NCS1, and VSNL1) and an additional three candidate ceramide-binding proteins (NCALD, HPCAL4, and KCNIP3) belong to the neuronal calcium sensor family of EF hand-containing proteins. We used mutagenesis to map the ceramide-binding site in HPCA and to create a mutant HPCA that does not bind to ceramide. We demonstrated selective binding to ceramide by mammalian cell-produced wild type but not mutant HPCA. Intriguingly, we also identified a fragment from prostaglandin D2synthase that binds preferentially to ceramide 1-phosphate. The wide variety of proteins and domains capable of binding to ceramide suggests that many of the signaling functions of ceramide may be regulated by direct binding to these proteins. Based on the deep sequencing data, we estimate that our yeast surface cDNA display library covers ∼60% of the human proteome and our selection/deep sequencing protocol can identify target-interacting protein fragments that are present at extremely low frequency in the starting library. Thus, the yeast surface cDNA display/deep sequencing approach is a rapid, comprehensive, and flexible method for the analysis of protein-ligand interactions, particularly for the study of non-protein ligands.
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Affiliation(s)
- Scott Bidlingmaier
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Kevin Ha
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Nam-Kyung Lee
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Yang Su
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Bin Liu
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
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26
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Lim S, Peshenko IV, Olshevskaya EV, Dizhoor AM, Ames JB. Structure of Guanylyl Cyclase Activator Protein 1 (GCAP1) Mutant V77E in a Ca2+-free/Mg2+-bound Activator State. J Biol Chem 2015; 291:4429-41. [PMID: 26703466 DOI: 10.1074/jbc.m115.696161] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 12/27/2022] Open
Abstract
GCAP1, a member of the neuronal calcium sensor subclass of the calmodulin superfamily, confers Ca(2+)-sensitive activation of retinal guanylyl cyclase 1 (RetGC1). We present NMR resonance assignments, residual dipolar coupling data, functional analysis, and a structural model of GCAP1 mutant (GCAP1(V77E)) in the Ca(2+)-free/Mg(2+)-bound state. NMR chemical shifts and residual dipolar coupling data reveal Ca(2+)-dependent differences for residues 170-174. An NMR-derived model of GCAP1(V77E) contains Mg(2+) bound at EF2 and looks similar to Ca(2+) saturated GCAP1 (root mean square deviations = 2.0 Å). Ca(2+)-dependent structural differences occur in the fourth EF-hand (EF4) and adjacent helical region (residues 164-174 called the Ca(2+) switch helix). Ca(2+)-induced shortening of the Ca(2+) switch helix changes solvent accessibility of Thr-171 and Leu-174 that affects the domain interface. Although the Ca(2+) switch helix is not part of the RetGC1 binding site, insertion of an extra Gly residue between Ser-173 and Leu-174 as well as deletion of Arg-172, Ser-173, or Leu-174 all caused a decrease in Ca(2+) binding affinity and abolished RetGC1 activation. We conclude that Ca(2+)-dependent conformational changes in the Ca(2+) switch helix are important for activating RetGC1 and provide further support for a Ca(2+)-myristoyl tug mechanism.
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Affiliation(s)
- Sunghyuk Lim
- From the Department of Chemistry, University of California, Davis, California 95616 and
| | - Igor V Peshenko
- Department of Research, Salus University, Elkins Park, Pennsylvania 19027
| | | | | | - James B Ames
- From the Department of Chemistry, University of California, Davis, California 95616 and
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Koch KW, Dell'Orco D. Protein and Signaling Networks in Vertebrate Photoreceptor Cells. Front Mol Neurosci 2015; 8:67. [PMID: 26635520 PMCID: PMC4646965 DOI: 10.3389/fnmol.2015.00067] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/26/2015] [Indexed: 01/10/2023] Open
Abstract
Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination. The photoexcitation and adaptation machinery in photoreceptor cells consists of protein complexes that can form highly ordered supramolecular structures and control the homeostasis and mutual dependence of the secondary messengers cyclic guanosine monophosphate (cGMP) and Ca2+. The visual pigment in rod photoreceptors, the G protein-coupled receptor rhodopsin is organized in tracks of dimers thereby providing a signaling platform for the dynamic scaffolding of the G protein transducin. Illuminated rhodopsin is turned off by phosphorylation catalyzed by rhodopsin kinase (GRK1) under control of Ca2+-recoverin. The GRK1 protein complex partly assembles in lipid raft structures, where shutting off rhodopsin seems to be more effective. Re-synthesis of cGMP is another crucial step in the recovery of the photoresponse after illumination. It is catalyzed by membrane bound sensory guanylate cyclases (GCs) and is regulated by specific neuronal Ca2+-sensor proteins called guanylate cyclase-activating proteins (GCAPs). At least one GC (ROS-GC1) was shown to be part of a multiprotein complex having strong interactions with the cytoskeleton and being controlled in a multimodal Ca2+-dependent fashion. The final target of the cGMP signaling cascade is a cyclic nucleotide-gated (CNG) channel that is a hetero-oligomeric protein located in the plasma membrane and interacting with accessory proteins in highly organized microdomains. We summarize results and interpretations of findings related to the inhomogeneous organization of signaling units in photoreceptor outer segments.
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Affiliation(s)
- Karl-Wilhelm Koch
- Department of Neurosciences, Biochemistry Group, University of Oldenburg Oldenburg, Germany
| | - Daniele Dell'Orco
- Department of Neurological, Biomedical and Movement Sciences, Section of Biological Chemistry and Center for BioMedical Computing (CBMC), University of Verona Verona, Italy
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28
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Devarie-Baez NO, Silva Lopez EI, Furdui CM. Biological chemistry and functionality of protein sulfenic acids and related thiol modifications. Free Radic Res 2015; 50:172-94. [PMID: 26340608 DOI: 10.3109/10715762.2015.1090571] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Selective modification of proteins at cysteine residues by reactive oxygen, nitrogen or sulfur species formed under physiological and pathological states is emerging as a critical regulator of protein activity impacting cellular function. This review focuses primarily on protein sulfenylation (-SOH), a metastable reversible modification connecting reduced cysteine thiols to many products of cysteine oxidation. An overview is first provided on the chemistry principles underlining synthesis, stability and reactivity of sulfenic acids in model compounds and proteins, followed by a brief description of analytical methods currently employed to characterize these oxidative species. The following chapters present a selection of redox-regulated proteins for which the -SOH formation was experimentally confirmed and linked to protein function. These chapters are organized based on the participation of these proteins in the regulation of signaling, metabolism and epigenetics. The last chapter discusses the therapeutic implications of altered redox microenvironment and protein oxidation in disease.
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Affiliation(s)
- Nelmi O Devarie-Baez
- a Department of Internal Medicine, Section on Molecular Medicine , Wake Forest School of Medicine , Winston-Salem , NC , USA
| | - Elsa I Silva Lopez
- a Department of Internal Medicine, Section on Molecular Medicine , Wake Forest School of Medicine , Winston-Salem , NC , USA
| | - Cristina M Furdui
- a Department of Internal Medicine, Section on Molecular Medicine , Wake Forest School of Medicine , Winston-Salem , NC , USA
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29
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Zernii EY, Grigoriev II, Nazipova AA, Scholten A, Kolpakova TV, Zinchenko DV, Kazakov AS, Senin II, Permyakov SE, Dell'Orco D, Philippov PP, Koch KW. Regulatory function of the C-terminal segment of guanylate cyclase-activating protein 2. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1325-37. [PMID: 26001899 DOI: 10.1016/j.bbapap.2015.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 04/22/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022]
Abstract
Neuronal responses to Ca2+-signals are provided by EF-hand-type neuronal Ca2+-sensor (NCS) proteins, which have similar core domains containing Ca2+-binding and target-recognizing sites. NCS proteins vary in functional specificity, probably depending on the structure and conformation of their non-conserved C-terminal segments. Here, we investigated the role of the C-terminal segment in guanylate cyclase activating protein-2, GCAP2, an NCS protein controlling the Ca2+-dependent regulation of photoreceptor guanylate cyclases. We obtained two chimeric proteins by exchanging C-terminal segments between GCAP2 and its photoreceptor homolog recoverin, a Ca2+-sensor controlling rhodopsin kinase (RK) activity. The exchange affected neither the structural integrity of GCAP2 and recoverin nor the Ca2+-sensitivity of GCAP2. Intrinsic fluorescence, circular dichroism, biochemical studies and hydrophobic dye probing revealed Ca2+-dependent conformational transition of the C-terminal segment of GCAP2 occurring in the molecular environment of both proteins. In Ca2+-GCAP2, the C-terminal segment was constrained and its replacement provided the protein with approximately two-fold inhibitory activity towards RK, suggesting that the segment contributes to specific target recognition by interfering with RK-binding. Upon Ca2+-release, it became less constrained and more available for phosphorylation by cyclic nucleotide-dependent protein kinase. The transition from the Ca2+-bound to the apo-state exposed hydrophobic sites in GCAP2, and was associated with its activating function without affecting its dimerization. The released C-terminal segment participated further in photoreceptor membrane binding making it sensitive to phosphorylation. Thus, the C-terminal segment in GCAP2 confers target selectivity, facilitates membrane binding and provides sensitivity of the membrane localization of the protein to phosphorylation by signaling kinases.
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Affiliation(s)
- Evgeni Yu Zernii
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - Ilya I Grigoriev
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - Aliya A Nazipova
- Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region, 142290 Russia
| | - Alexander Scholten
- Department of Neurosciences, Biochemistry Group, University of Oldenburg, Oldenburg, 26111 Germany
| | - Tatiana V Kolpakova
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - Dmitry V Zinchenko
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Pushchino, Moscow region, 142290 Russia
| | - Alexey S Kazakov
- Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region, 142290 Russia
| | - Ivan I Senin
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - Sergei E Permyakov
- Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region, 142290 Russia
| | - Daniele Dell'Orco
- Department of Life Sciences and Reproduction, Section of Biological Chemistry and Center for BioMedical Computing, University of Verona, Verona, 37134 Italy
| | - Pavel P Philippov
- Department of Cell Signaling, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - Karl-W Koch
- Department of Neurosciences, Biochemistry Group, University of Oldenburg, Oldenburg, 26111 Germany.
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30
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Sharma RK, Baehr W, Makino CL, Duda T. Ca(2+) and Ca(2+)-interlocked membrane guanylate cyclase signal modulation of neuronal and cardiovascular signal transduction. Front Mol Neurosci 2015; 8:7. [PMID: 25798085 PMCID: PMC4351612 DOI: 10.3389/fnmol.2015.00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/16/2015] [Indexed: 12/29/2022] Open
Affiliation(s)
- Rameshwar K Sharma
- Research Divisions of Biochemistry and Molecular Biology, The Unit of Regulatory and Molecular Biology, Salus University Elkins Park, PA, USA
| | - Wolfgang Baehr
- School of Medicine, Department of Ophthalmology and Visual Sciences, University of Utah Salt Lake City, UT, USA
| | - Clint L Makino
- Massachusetts Eye and Ear Infirmary and Harvard Medical School Boston, MA, USA
| | - Teresa Duda
- Research Divisions of Biochemistry and Molecular Biology, The Unit of Regulatory and Molecular Biology, Salus University Elkins Park, PA, USA
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31
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Wen XH, Dizhoor AM, Makino CL. Membrane guanylyl cyclase complexes shape the photoresponses of retinal rods and cones. Front Mol Neurosci 2014; 7:45. [PMID: 24917784 PMCID: PMC4040495 DOI: 10.3389/fnmol.2014.00045] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/01/2014] [Indexed: 12/02/2022] Open
Abstract
In vertebrate rods and cones, photon capture by rhodopsin leads to the destruction of cyclic GMP (cGMP) and the subsequent closure of cyclic nucleotide gated ion channels in the outer segment plasma membrane. Replenishment of cGMP and reopening of the channels limit the growth of the photon response and are requisite for its recovery. In different vertebrate retinas, there may be as many as four types of membrane guanylyl cyclases (GCs) for cGMP synthesis. Ten neuronal Ca2+ sensor proteins could potentially modulate their activities. The mouse is proving to be an effective model for characterizing the roles of individual components because its relative simplicity can be reduced further by genetic engineering. There are two types of GC activating proteins (GCAPs) and two types of GCs in mouse rods, whereas cones express one type of GCAP and one type of GC. Mutant mouse rods and cones bereft of both GCAPs have large, long lasting photon responses. Thus, GCAPs normally mediate negative feedback tied to the light-induced decline in intracellular Ca2+ that accelerates GC activity to curtail the growth and duration of the photon response. Rods from other mutant mice that express a single GCAP type reveal how the two GCAPs normally work together as a team. Because of its lower Ca2+ affinity, GCAP1 is the first responder that senses the initial decrease in Ca2+ following photon absorption and acts to limit response amplitude. GCAP2, with a higher Ca2+ affinity, is recruited later during the course of the photon response as Ca2+ levels continue to decline further. The main role of GCAP2 is to provide for a timely response recovery and it is particularly important after exposure to very bright light. The multiplicity of GC isozymes and GCAP homologs in the retinas of other vertebrates confers greater flexibility in shaping the photon responses in order to tune visual sensitivity, dynamic range and frequency response.
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Affiliation(s)
- Xiao-Hong Wen
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary and Harvard Medical School Boston, MA, USA
| | - Alexander M Dizhoor
- Department of Basic Sciences Research and Pennsylvania College of Optometry, Salus University Elkins Park, PA, USA
| | - Clint L Makino
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary and Harvard Medical School Boston, MA, USA
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