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Li Z, Wu Q, Yan N. A structural atlas of druggable sites on Na v channels. Channels (Austin) 2024; 18:2287832. [PMID: 38033122 PMCID: PMC10732651 DOI: 10.1080/19336950.2023.2287832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023] Open
Abstract
Voltage-gated sodium (Nav) channels govern membrane excitability by initiating and propagating action potentials. Consistent with their physiological significance, dysfunction, or mutations in these channels are associated with various channelopathies. Nav channels are thereby major targets for various clinical and investigational drugs. In addition, a large number of natural toxins, both small molecules and peptides, can bind to Nav channels and modulate their functions. Technological breakthrough in cryo-electron microscopy (cryo-EM) has enabled the determination of high-resolution structures of eukaryotic and eventually human Nav channels, alone or in complex with auxiliary subunits, toxins, and drugs. These studies have not only advanced our comprehension of channel architecture and working mechanisms but also afforded unprecedented clarity to the molecular basis for the binding and mechanism of action (MOA) of prototypical drugs and toxins. In this review, we will provide an overview of the recent advances in structural pharmacology of Nav channels, encompassing the structural map for ligand binding on Nav channels. These findings have established a vital groundwork for future drug development.
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Affiliation(s)
- Zhangqiang Li
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiurong Wu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong Province, China
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2
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Tibery DV, Nunes JAA, da Mata DO, Menezes LFS, de Souza ACB, Fernandes-Pedrosa MDF, Treptow W, Schwartz EF. Unveiling Tst3, a Multi-Target Gating Modifier Scorpion α Toxin from Tityus stigmurus Venom of Northeast Brazil: Evaluation and Comparison with Well-Studied Ts3 Toxin of Tityus serrulatus. Toxins (Basel) 2024; 16:257. [PMID: 38922152 PMCID: PMC11209618 DOI: 10.3390/toxins16060257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/27/2024] [Accepted: 05/30/2024] [Indexed: 06/27/2024] Open
Abstract
Studies on the interaction sites of peptide toxins and ion channels typically involve site-directed mutations in toxins. However, natural mutant toxins exist among them, offering insights into how the evolutionary process has conserved crucial sequences for activities and molecular target selection. In this study, we present a comparative investigation using electrophysiological approaches and computational analysis between two alpha toxins from evolutionarily close scorpion species of the genus Tityus, namely, Tst3 and Ts3 from T. stigmurus and T. serrulatus, respectively. These toxins exhibit three natural substitutions near the C-terminal region, which is directly involved in the interaction between alpha toxins and Nav channels. Additionally, we characterized the activity of the Tst3 toxin on Nav1.1-Nav1.7 channels. The three natural changes between the toxins did not alter sensitivity to Nav1.4, maintaining similar intensities regarding their ability to alter opening probabilities, delay fast inactivation, and induce persistent currents. Computational analysis demonstrated a preference for the down conformation of VSD4 and a shift in the conformational equilibrium towards this state. This illustrates that the sequence of these toxins retained the necessary information, even with alterations in the interaction site region. Through electrophysiological and computational analyses, screening of the Tst3 toxin on sodium isoform revealed its classification as a classic α-NaTx with a broad spectrum of activity. It effectively delays fast inactivation across all tested isoforms. Structural analysis of molecular energetics at the interface of the VSD4-Tst3 complex further confirmed this effect.
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Affiliation(s)
- Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (D.V.T.); (D.O.d.M.); (L.F.S.M.); (A.C.B.d.S.)
| | - João Antonio Alves Nunes
- Laboratório de Biologia Teórica e Computacional (LBTC), Departamento de Biologia Celular, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (J.A.A.N.); (W.T.)
| | - Daniel Oliveira da Mata
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (D.V.T.); (D.O.d.M.); (L.F.S.M.); (A.C.B.d.S.)
| | - Luis Felipe Santos Menezes
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (D.V.T.); (D.O.d.M.); (L.F.S.M.); (A.C.B.d.S.)
| | - Adolfo Carlos Barros de Souza
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (D.V.T.); (D.O.d.M.); (L.F.S.M.); (A.C.B.d.S.)
| | - Matheus de Freitas Fernandes-Pedrosa
- Laboratório de Tecnologia e Biotecnologia Farmacêutica, Departamento de Farmácia, Universidade Federal do Rio Grande do Norte (UFRN), Natal 59012-570, Rio Grande do Norte, Brazil;
| | - Werner Treptow
- Laboratório de Biologia Teórica e Computacional (LBTC), Departamento de Biologia Celular, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (J.A.A.N.); (W.T.)
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília (UnB), Brasília 70910-900, Distrito Federal, Brazil; (D.V.T.); (D.O.d.M.); (L.F.S.M.); (A.C.B.d.S.)
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3
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González-González MA, Conde SV, Latorre R, Thébault SC, Pratelli M, Spitzer NC, Verkhratsky A, Tremblay MÈ, Akcora CG, Hernández-Reynoso AG, Ecker M, Coates J, Vincent KL, Ma B. Bioelectronic Medicine: a multidisciplinary roadmap from biophysics to precision therapies. Front Integr Neurosci 2024; 18:1321872. [PMID: 38440417 PMCID: PMC10911101 DOI: 10.3389/fnint.2024.1321872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/10/2024] [Indexed: 03/06/2024] Open
Abstract
Bioelectronic Medicine stands as an emerging field that rapidly evolves and offers distinctive clinical benefits, alongside unique challenges. It consists of the modulation of the nervous system by precise delivery of electrical current for the treatment of clinical conditions, such as post-stroke movement recovery or drug-resistant disorders. The unquestionable clinical impact of Bioelectronic Medicine is underscored by the successful translation to humans in the last decades, and the long list of preclinical studies. Given the emergency of accelerating the progress in new neuromodulation treatments (i.e., drug-resistant hypertension, autoimmune and degenerative diseases), collaboration between multiple fields is imperative. This work intends to foster multidisciplinary work and bring together different fields to provide the fundamental basis underlying Bioelectronic Medicine. In this review we will go from the biophysics of the cell membrane, which we consider the inner core of neuromodulation, to patient care. We will discuss the recently discovered mechanism of neurotransmission switching and how it will impact neuromodulation design, and we will provide an update on neuronal and glial basis in health and disease. The advances in biomedical technology have facilitated the collection of large amounts of data, thereby introducing new challenges in data analysis. We will discuss the current approaches and challenges in high throughput data analysis, encompassing big data, networks, artificial intelligence, and internet of things. Emphasis will be placed on understanding the electrochemical properties of neural interfaces, along with the integration of biocompatible and reliable materials and compliance with biomedical regulations for translational applications. Preclinical validation is foundational to the translational process, and we will discuss the critical aspects of such animal studies. Finally, we will focus on the patient point-of-care and challenges in neuromodulation as the ultimate goal of bioelectronic medicine. This review is a call to scientists from different fields to work together with a common endeavor: accelerate the decoding and modulation of the nervous system in a new era of therapeutic possibilities.
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Affiliation(s)
- María Alejandra González-González
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
- Department of Pediatric Neurology, Baylor College of Medicine, Houston, TX, United States
| | - Silvia V. Conde
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NOVA University, Lisbon, Portugal
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stéphanie C. Thébault
- Laboratorio de Investigación Traslacional en salud visual (D-13), Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Marta Pratelli
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Nicholas C. Spitzer
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
- International Collaborative Center on Big Science Plan for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Cuneyt G. Akcora
- Department of Computer Science, University of Central Florida, Orlando, FL, United States
| | | | - Melanie Ecker
- Department of Biomedical Engineering, University of North Texas, Denton, TX, United States
| | | | - Kathleen L. Vincent
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, United States
| | - Brandy Ma
- Stanley H. Appel Department of Neurology, Houston Methodist Hospital, Houston, TX, United States
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4
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Catterall WA. Voltage gated sodium and calcium channels: Discovery, structure, function, and Pharmacology. Channels (Austin) 2023; 17:2281714. [PMID: 37983307 PMCID: PMC10761118 DOI: 10.1080/19336950.2023.2281714] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/11/2023] [Indexed: 11/22/2023] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve and muscle, and voltage-gated calcium channels couple depolarization of the plasma membrane to intracellular events such as secretion, contraction, synaptic transmission, and gene expression. In this Review and Perspective article, I summarize early work that led to identification, purification, functional reconstitution, and determination of the amino acid sequence of the protein subunits of sodium and calcium channels and showed that their pore-forming subunits are closely related. Decades of study by antibody mapping, site-directed mutagenesis, and electrophysiological recording led to detailed two-dimensional structure-function maps of the amino acid residues involved in voltage-dependent activation and inactivation, ion permeation and selectivity, and pharmacological modulation. Most recently, high-resolution three-dimensional structure determination by X-ray crystallography and cryogenic electron microscopy has revealed the structural basis for sodium and calcium channel function and pharmacological modulation at the atomic level. These studies now define the chemical basis for electrical signaling and provide templates for future development of new therapeutic agents for a range of neurological and cardiovascular diseases.
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5
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Bian Y, Tuo J, He L, Li W, Li S, Chu H, Zhao Y. Voltage-gated sodium channels in cancer and their specific inhibitors. Pathol Res Pract 2023; 251:154909. [PMID: 37939447 DOI: 10.1016/j.prp.2023.154909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/10/2023]
Abstract
Voltage-gated sodium channels (VGSCs) participate in generating and spreading action potentials in electrically excited cells such as neurons and muscle fibers. Abnormal expression of VGSCs has been observed in various types of tumors, while they are either not expressed or expressed at a low level in the matching normal tissue. Hence, this abnormal expression suggests that VGSCs confer some advantage or viability on tumor cells, making them a valuable indicator for identifying tumor cells. In addition, overexpression of VGSCs increased the ability of cancer cells to metastasize and invade, as well as correlated with the metastatic behavior of different cancers. Therefore, blocking VGSCs presents a new strategy for the treatment of cancers. A portion of this review summarizes the structure and function of VGSCs and also describes the correlation between VGSCs and cancers. Most importantly, we provide an overview of current research on various subtype-selective VGSC inhibitors and updates on ongoing clinical studies.
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Affiliation(s)
- Yuan Bian
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Jiale Tuo
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Liangpeng He
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Wenwen Li
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Shangxiao Li
- School of Medical Devices, Shenyang Pharmaceutical University, Benxi, Liaoning 117004, PR China
| | - Huiying Chu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Yongshan Zhao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China.
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6
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Ben-Abu Y. Quantum mechanics in ion channel. Biophys Chem 2023; 300:107071. [PMID: 37429150 DOI: 10.1016/j.bpc.2023.107071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/21/2023] [Accepted: 06/24/2023] [Indexed: 07/12/2023]
Abstract
Many attempts have been made to associate physical systems with system biology. Most of them are showing very impressive analogs. However, in quantum mechanics, very limited data and knowledge are available regarding analogs. The ion movement is approximately constant in velocity since the time periods are so small and are negligible. In this study, I focused on a new aspect of ion channels using quantum mechanics. Suppose that the time required for the ion to cross a distance between two gates.
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Affiliation(s)
- Yuval Ben-Abu
- Physics Unit, Sapir Academic College, Hof Ashkelon, Sderot 79165, Israel.
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7
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Catacuzzeno L, Conti F, Franciolini F. Fifty years of gating currents and channel gating. J Gen Physiol 2023; 155:e202313380. [PMID: 37410612 PMCID: PMC10324510 DOI: 10.1085/jgp.202313380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023] Open
Abstract
We celebrate this year the 50th anniversary of the first electrophysiological recordings of the gating currents from voltage-dependent ion channels done in 1973. This retrospective tries to illustrate the context knowledge on channel gating and the impact gating-current recording had then, and how it continued to clarify concepts, elaborate new ideas, and steer the scientific debate in these 50 years. The notion of gating particles and gating currents was first put forward by Hodgkin and Huxley in 1952 as a necessary assumption for interpreting the voltage dependence of the Na and K conductances of the action potential. 20 years later, gating currents were actually recorded, and over the following decades have represented the most direct means of tracing the movement of the gating charges and gaining insights into the mechanisms of channel gating. Most work in the early years was focused on the gating currents from the Na and K channels as found in the squid giant axon. With channel cloning and expression on heterologous systems, other channels as well as voltage-dependent enzymes were investigated. Other approaches were also introduced (cysteine mutagenesis and labeling, site-directed fluorometry, cryo-EM crystallography, and molecular dynamics [MD] modeling) to provide an integrated and coherent view of voltage-dependent gating in biological macromolecules. The layout of this retrospective reflects the past 50 years of investigations on gating currents, first addressing studies done on Na and K channels and then on other voltage-gated channels and non-channel structures. The review closes with a brief overview of how the gating-charge/voltage-sensor movements are translated into pore opening and the pathologies associated with mutations targeting the structures involved with the gating currents.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Franco Conti
- Department of Physics, University of Genova, Genova, Italy
| | - Fabio Franciolini
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
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8
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Paruch K, Kaproń B, Łuszczki JJ, Paneth A, Plech T. Effect of Linker Elongation on the VGSC Affinity and Anticonvulsant Activity among 4-Alkyl-5-aryl-1,2,4-triazole-3-thione Derivatives. Molecules 2023; 28:5287. [PMID: 37446948 DOI: 10.3390/molecules28135287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
The main aim of the current project was to investigate the effect of the linker size in 4-alkyl-5-aryl-1,2,4-triazole-3-thione derivatives, known as a group of antiepileptic drug candidates, on their affinity towards voltage-gated sodium channels (VGSCs). The rationale of the study was based both on the SAR observations and docking simulations of the interactions between the designed ligands and the binding site of human VGSC. HYDE docking scores, which describe hydrogen bonding, desolvation, and hydrophobic effects, obtained for 5-[(3-chlorophenyl)ethyl]-4-butyl/hexyl-1,2,4-triazole-3-thiones, justified their beneficial sodium channel blocking activity. The results of docking simulations were verified using a radioligand binding assay with [3H]batrachotoxin. Unexpectedly, although the investigated triazole-based compounds acted as VGSC ligands, their affinities were lower than those of the respective analogs containing shorter alkyl linkers. Since numerous sodium channel blockers are recognized as antiepileptic agents, the obtained 1,2,4-triazole derivatives were examined for antiepileptic potential using an experimental model of tonic-clonic seizures in mice. Median effective doses (ED50) of the compounds examined in MES test reached 96.6 ± 14.8 mg/kg, while their median toxic doses (TD50), obtained in the rotarod test, were even as high as 710.5 ± 47.4 mg/kg.
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Affiliation(s)
- Kinga Paruch
- Department of Pharmacology, Faculty of Health Sciences, Medical University of Lublin, Radziwiłłowska 11, 20-080 Lublin, Poland
| | - Barbara Kaproń
- Department of Clinical Genetics, Faculty of Medicine, Medical University of Lublin, Radziwiłłowska 11, 20-080 Lublin, Poland
| | - Jarogniew J Łuszczki
- Department of Occupational Medicine, Faculty of Medical Sciences, Medical University of Lublin, Jaczewskiego 8B, 20-090 Lublin, Poland
| | - Agata Paneth
- Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Lublin, Chodźki 4A, 20-059 Lublin, Poland
| | - Tomasz Plech
- Department of Pharmacology, Faculty of Health Sciences, Medical University of Lublin, Radziwiłłowska 11, 20-080 Lublin, Poland
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Unwinding and spiral sliding of S4 and domain rotation of VSD during the electromechanical coupling in Na v1.7. Proc Natl Acad Sci U S A 2022; 119:e2209164119. [PMID: 35878056 PMCID: PMC9388133 DOI: 10.1073/pnas.2209164119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nav1.7 has been targeted for pain management for its well-established role in pain sensation. Hundreds of mutations of Nav1.7 have been found in patients with pain disorders. Structures of Nav1.7 captured in different conformations will reveal its working mechanism and facilitate drug discovery. Here we present the rational design of a Nav1.7 variant, Nav1.7-M11, that may be trapped in the closed-state inactivation conformation at 0 mV. Cryoelectron microscopy analysis of Nav1.7-M11 reveals voltage-sensing domain in the first repeat (VSDI) in the completely down conformation, VSDII at an intermediate state, and the pore domain tightly closed. Structural comparison of Nav1.7-M11 with the WT channel provides unprecedented insight into the electromechanical coupling details and affords mechanistic interpretation for a number of pain-related mutations. Voltage-gated sodium (Nav) channel Nav1.7 has been targeted for the development of nonaddictive pain killers. Structures of Nav1.7 in distinct functional states will offer an advanced mechanistic understanding and aid drug discovery. Here we report the cryoelectron microscopy analysis of a human Nav1.7 variant that, with 11 rationally introduced point mutations, has a markedly right-shifted activation voltage curve with V1/2 reaching 69 mV. The voltage-sensing domain in the first repeat (VSDI) in a 2.7-Å resolution structure displays a completely down (deactivated) conformation. Compared to the structure of WT Nav1.7, three gating charge (GC) residues in VSDI are transferred to the cytosolic side through a combination of helix unwinding and spiral sliding of S4I and ∼20° domain rotation. A conserved WNФФD motif on the cytoplasmic end of S3I stabilizes the down conformation of VSDI. One GC residue is transferred in VSDII mainly through helix sliding. Accompanying GC transfer in VSDI and VSDII, rearrangement and contraction of the intracellular gate is achieved through concerted movements of adjacent segments, including S4-5I, S4-5II, S5II, and all S6 segments. Our studies provide important insight into the electromechanical coupling mechanism of the single-chain voltage-gated ion channels and afford molecular interpretations for a number of pain-associated mutations whose pathogenic mechanism cannot be revealed from previously reported Nav structures.
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Catacuzzeno L, Franciolini F. The 70-year search for the voltage sensing mechanism of ion channels. J Physiol 2022; 600:3227-3247. [PMID: 35665931 PMCID: PMC9545881 DOI: 10.1113/jp282780] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/25/2022] [Indexed: 01/10/2023] Open
Abstract
This retrospective on the voltage‐sensing mechanisms and gating models of ion channels begins in 1952 with the charged gating particles postulated by Hodgkin and Huxley, viewed as charges moving across the membrane and controlling its permeability to Na+ and K+ ions. Hodgkin and Huxley postulated that their movement should generate small and fast capacitive currents, which were recorded 20 years later as gating currents. In the early 1980s, several voltage‐dependent channels were cloned and found to share a common architecture: four homologous domains or subunits, each displaying six transmembrane α‐helical segments, with the fourth segment (S4) displaying four to seven positive charges invariably separated by two non‐charged residues. This immediately suggested that this segment was serving as the voltage sensor of the channel (the molecular counterpart of the charged gating particle postulated by Hodgkin and Huxley) and led to the development of the sliding helix model. Twenty years later, the X‐ray crystallographic structures of many voltage‐dependent channels allowed investigation of their gating by molecular dynamics. Further understanding of how channels gate will benefit greatly from the acquisition of high‐resolution structures of each of their relevant functional or structural states. This will allow the application of molecular dynamics and other approaches. It will also be key to investigate the energetics of channel gating, permitting an understanding of the physical and molecular determinants of gating. The use of multiscale hierarchical approaches might finally prove to be a rewarding strategy to overcome the limits of the various single approaches to the study of channel gating.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Italy
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11
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Complex effects on Ca V2.1 channel gating caused by a CACNA1A variant associated with a severe neurodevelopmental disorder. Sci Rep 2022; 12:9186. [PMID: 35655070 PMCID: PMC9163077 DOI: 10.1038/s41598-022-12789-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 05/16/2022] [Indexed: 01/25/2023] Open
Abstract
P/Q-type Ca2+ currents mediated by CaV2.1 channels are essential for active neurotransmitter release at neuromuscular junctions and many central synapses. Mutations in CACNA1A, the gene encoding the principal CaV2.1 α1A subunit, cause a broad spectrum of neurological disorders. Typically, gain-of-function (GOF) mutations are associated with migraine and epilepsy while loss-of-function (LOF) mutations are causative for episodic and congenital ataxias. However, a cluster of severe CaV2.1 channelopathies have overlapping presentations which suggests that channel dysfunction in these disorders cannot always be defined bimodally as GOF or LOF. In particular, the R1667P mutation causes focal seizures, generalized hypotonia, dysarthria, congenital ataxia and, in one case, cerebral edema leading ultimately to death. Here, we demonstrate that the R1667P mutation causes both channel GOF (hyperpolarizing voltage-dependence of activation, slowed deactivation) and LOF (slowed activation kinetics) when expressed heterologously in tsA-201 cells. We also observed a substantial reduction in Ca2+ current density in this heterologous system. These changes in channel gating and availability/expression manifested in diminished Ca2+ flux during action potential-like stimuli. However, the integrated Ca2+ fluxes were no different when normalized to tail current amplitude measured upon repolarization from the reversal potential. In summary, our findings indicate a complex functional effect of R1667P and support the idea that pathological missense mutations in CaV2.1 may not represent exclusively GOF or LOF.
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12
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Körner J, Albani S, Sudha Bhagavath Eswaran V, Roehl AB, Rossetti G, Lampert A. Sodium Channels and Local Anesthetics-Old Friends With New Perspectives. Front Pharmacol 2022; 13:837088. [PMID: 35418860 PMCID: PMC8996304 DOI: 10.3389/fphar.2022.837088] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/16/2022] [Indexed: 12/11/2022] Open
Abstract
The long history of local anesthetics (LAs) starts out in the late 19th century when the content of coca plant leaves was discovered to alleviate pain. Soon after, cocaine was established and headed off to an infamous career as a substance causing addiction. Today, LAs and related substances-in modified form-are indispensable in our clinical everyday life for pain relief during and after minor and major surgery, and dental practices. In this review, we elucidate on the interaction of modern LAs with their main target, the voltage-gated sodium channel (Navs), in the light of the recently published channel structures. Knowledge of the 3D interaction sites of the drug with the protein will allow to mechanistically substantiate the comprehensive data available on LA gating modification. In the 1970s it was suggested that LAs can enter the channel pore from the lipid phase, which was quite prospective at that time. Today we know from cryo-electron microscopy structures and mutagenesis experiments, that indeed Navs have side fenestrations facing the membrane, which are likely the entrance for LAs to induce tonic block. In this review, we will focus on the effects of LA binding on fast inactivation and use-dependent inhibition in the light of the proposed new allosteric mechanism of fast inactivation. We will elaborate on subtype and species specificity and provide insights into modelling approaches that will help identify the exact molecular binding orientation, access pathways and pharmacokinetics. With this comprehensive overview, we will provide new perspectives in the use of the drug, both clinically and as a tool for basic ion channel research.
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Affiliation(s)
- Jannis Körner
- Institute of Physiology, Aachen, Germany.,Clinic of Anesthesiology, Medical Faculty, Uniklinik RWTH Aachen, Aachen, Germany
| | - Simone Albani
- Institute for Neuroscience and Medicine (INM-9/IAS-5), Forschungszentrum Jülich, Jülich, Germany.,Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, Aachen, Germany
| | | | - Anna B Roehl
- Clinic of Anesthesiology, Medical Faculty, Uniklinik RWTH Aachen, Aachen, Germany
| | - Giulia Rossetti
- Institute for Neuroscience and Medicine (INM-9/IAS-5), Forschungszentrum Jülich, Jülich, Germany.,Jülich Supercomputing Center (JSC), Forschungszentrum Jülich, Aachen, Germany.,Department of Neurology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
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13
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Wong JC, Butler KM, Shapiro L, Thelin JT, Mattison KA, Garber KB, Goldenberg PC, Kubendran S, Schaefer GB, Escayg A. Pathogenic in-Frame Variants in SCN8A: Expanding the Genetic Landscape of SCN8A-Associated Disease. Front Pharmacol 2021; 12:748415. [PMID: 34867351 PMCID: PMC8635767 DOI: 10.3389/fphar.2021.748415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/21/2021] [Indexed: 01/11/2023] Open
Abstract
Numerous SCN8A mutations have been identified, of which, the majority are de novo missense variants. Most mutations result in epileptic encephalopathy; however, some are associated with less severe phenotypes. Mouse models generated by knock-in of human missense SCN8A mutations exhibit seizures and a range of behavioral abnormalities. To date, there are only a few Scn8a mouse models with in-frame deletions or insertions, and notably, none of these mouse lines exhibit increased seizure susceptibility. In the current study, we report the generation and characterization of two Scn8a mouse models (ΔIRL/+ and ΔVIR/+) carrying overlapping in-frame deletions within the voltage sensor of domain 4 (DIVS4). Both mouse lines show increased seizure susceptibility and infrequent spontaneous seizures. We also describe two unrelated patients with the same in-frame SCN8A deletion in the DIV S5-S6 pore region, highlighting the clinical relevance of this class of mutations.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, GA, United States.,Greenwood Genetic Center, Greenwood, SC, United States
| | - Lindsey Shapiro
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Jacquelyn T Thelin
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kari A Mattison
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kathryn B Garber
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Paula C Goldenberg
- Department of Pediatrics and Medical Genetics, Harvard Medical School, Boston, MA, United States
| | - Shobana Kubendran
- Department of Pediatrics, Kansas University School of Medicine-Wichita, Wichita, KS, United States
| | - G Bradley Schaefer
- University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, United States
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14
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Boonamnaj P, Pandey RB, Sompornpisut P. Interaction fingerprint of transmembrane segments in voltage sensor domains. Biophys Chem 2021; 277:106649. [PMID: 34147849 DOI: 10.1016/j.bpc.2021.106649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/06/2021] [Accepted: 06/09/2021] [Indexed: 11/30/2022]
Abstract
Voltage sensor domain (VSD) in channel and non-channel membrane proteins shares a common function in the detection of changes in the transmembrane electric potential. The VSD is made of four helical transmembrane segments (S1-S4) that form a structurally conserved scaffold through inter-transmembrane residue-residue interactions. Details about these interactions are yet to be fully understood in the context of the unique structural and physical characteristics of the voltage sensor unit. In this study, molecular dynamics simulations were carried out to investigate transmembrane helix-helix interactions via residue-based nonbonding energies using the activated and resting state conformations of VSD from Hv1, CiVSP, KvAP and NavAb. Inter-transmembrane interaction energies within the VSD were determined. Analysis of electrostatic and van der Waals components revealed the strengths and weaknesses of the interactions between each pair of transmembrane segments. In all cases the S4 helix had the highest electrostatic contribution to favor the key role as the voltage sensitive segment. Electrostatic interactions for the S1-S2 pair as well as the S1-S3 pair were relatively weak. Van der Waal interaction energies between adjacent segments were on average greater than that between diagonally opposite segments. Salt bridge interactions between S4-arginines and the negatively charged residues in other segments appear to contribute more to stabilizing the energy than the van der Waals interactions between nonpolar residues. The overall behavior of residue-residue contacts is similar among the transmembrane domains, reflecting the common inter- transmembrane interaction pattern in the VSD. In addition, analysis of the residue positions suggested that subtle differences in the orientation of the salt-bridges can be attributed to the difference in the inter-transmembrane interaction strengths inside the VSDs.
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Affiliation(s)
- Panisak Boonamnaj
- The Center of Excellence in Computational Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - R B Pandey
- School of Mathematics and Natural Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Pornthep Sompornpisut
- The Center of Excellence in Computational Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
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15
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Angsutararux P, Kang PW, Zhu W, Silva JR. Conformations of voltage-sensing domain III differentially define NaV channel closed- and open-state inactivation. J Gen Physiol 2021; 153:212533. [PMID: 34347027 PMCID: PMC8348240 DOI: 10.1085/jgp.202112891] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/14/2021] [Indexed: 11/21/2022] Open
Abstract
Voltage-gated Na+ (NaV) channels underlie the initiation and propagation of action potentials (APs). Rapid inactivation after NaV channel opening, known as open-state inactivation, plays a critical role in limiting the AP duration. However, NaV channel inactivation can also occur before opening, namely closed-state inactivation, to tune the cellular excitability. The voltage-sensing domain (VSD) within repeat IV (VSD-IV) of the pseudotetrameric NaV channel α-subunit is known to be a critical regulator of NaV channel inactivation. Yet, the two processes of open- and closed-state inactivation predominate at different voltage ranges and feature distinct kinetics. How inactivation occurs over these different ranges to give rise to the complexity of NaV channel dynamics is unclear. Past functional studies and recent cryo-electron microscopy structures, however, reveal significant inactivation regulation from other NaV channel components. In this Hypothesis paper, we propose that the VSD of NaV repeat III (VSD-III), together with VSD-IV, orchestrates the inactivation-state occupancy of NaV channels by modulating the affinity of the intracellular binding site of the IFMT motif on the III-IV linker. We review and outline substantial evidence that VSD-III activates in two distinct steps, with the intermediate and fully activated conformation regulating closed- and open-state inactivation state occupancy by altering the formation and affinity of the IFMT crevice. A role of VSD-III in determining inactivation-state occupancy and recovery from inactivation suggests a regulatory mechanism for the state-dependent block by small-molecule anti-arrhythmic and anesthetic therapies.
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Affiliation(s)
- Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
| | - Po Wei Kang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
| | - Wandi Zhu
- Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
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16
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Pal R, Kumar B, Akhtar MJ, Chawla PA. Voltage gated sodium channel inhibitors as anticonvulsant drugs: A systematic review on recent developments and structure activity relationship studies. Bioorg Chem 2021; 115:105230. [PMID: 34416507 DOI: 10.1016/j.bioorg.2021.105230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/28/2022]
Abstract
Voltage-gated sodium channel blockers are one of the vital targets for the management of several central nervous system diseases, including epilepsy, chronic pain, psychiatric disorders, and spasticity. The voltage-gated sodium channels play a key role in controlling cellular excitability. This reduction in excitotoxicity is also applied to improve the symptoms of epileptic conditions. The effectiveness of antiepileptic drugs as sodium channel depends upon the reversible blocking of the spontaneous discharge without blocking its propagation. There are number of antiepileptic drug(s) which are in pipeline to flour the market to conquer abnormal neuronal excitability. They inhibit the seizures through the inhibition of complex voltage- and frequency-dependent ionic currents through sodium channels. Over the past decade, the sodium channel is one of the most explored targets to control or treat the seizure, but there has not been any game-changing discovery yet. Although there are large numbers of drugs approved for the treatment of epilepsy, however they are associated with several acute to chronic side effects. Many research groups have tirelessly worked for better therapeutic medication on this popular target to treat epileptic seizures. The review quotes briefly the developments of the approved examples of sodium channel blockers as anticonvulsant drugs. Medicinal chemists have tried the design and development of some more potent anticonvulsant drugs to minimize the toxicity that are discussed here, and an emphasis is given for their possible mechanism and the structure-activity relationship (SAR).
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Affiliation(s)
- Rohit Pal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Bhupinder Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Md Jawaid Akhtar
- Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO620, PC 130 Azaiba, Bousher, Muscat, Sultanate of Oman
| | - Pooja A Chawla
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India.
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17
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Li Z, Jin X, Wu T, Huang G, Wu K, Lei J, Pan X, Yan N. Structural Basis for Pore Blockade of the Human Cardiac Sodium Channel Na v 1.5 by the Antiarrhythmic Drug Quinidine*. Angew Chem Int Ed Engl 2021; 60:11474-11480. [PMID: 33684260 DOI: 10.1002/anie.202102196] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Indexed: 12/19/2022]
Abstract
Nav 1.5, the primary voltage-gated Na+ (Nav ) channel in heart, is a major target for class I antiarrhythmic agents. Here we present the cryo-EM structure of full-length human Nav 1.5 bound to quinidine, a class Ia antiarrhythmic drug, at 3.3 Å resolution. Quinidine is positioned right beneath the selectivity filter in the pore domain and coordinated by residues from repeats I, III, and IV. Pore blockade by quinidine is achieved through both direct obstruction of the ion permeation path and induced rotation of an invariant Tyr residue that tightens the intracellular gate. Structural comparison with a truncated rat Nav 1.5 in the presence of flecainide, a class Ic agent, reveals distinct binding poses for the two antiarrhythmics within the pore domain. Our work reported here, along with previous studies, reveals the molecular basis for the mechanism of action of class I antiarrhythmic drugs.
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Affiliation(s)
- Zhangqiang Li
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xueqin Jin
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Tong Wu
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Gaoxingyu Huang
- Key Laboratory of Structural Biology of Zhejiang Province, Institute of Biology, Westlake Institute for Advanced Study, School of Life Sciences, Westlake University, Hangzhou, 310024, Zhejiang Province, China
| | - Kun Wu
- Medical Research Center, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
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18
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Li Z, Jin X, Wu T, Huang G, Wu K, Lei J, Pan X, Yan N. Structural Basis for Pore Blockade of the Human Cardiac Sodium Channel Na
v
1.5 by the Antiarrhythmic Drug Quinidine**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zhangqiang Li
- State Key Laboratory of Membrane Biology Beijing Advanced Innovation Center for Structural Biology Tsinghua-Peking Joint Center for Life Science School of Life Sciences Tsinghua University Beijing 100084 China
| | - Xueqin Jin
- State Key Laboratory of Membrane Biology Beijing Advanced Innovation Center for Structural Biology Tsinghua-Peking Joint Center for Life Science School of Life Sciences Tsinghua University Beijing 100084 China
| | - Tong Wu
- State Key Laboratory of Membrane Biology Beijing Advanced Innovation Center for Structural Biology Tsinghua-Peking Joint Center for Life Science School of Life Sciences Tsinghua University Beijing 100084 China
| | - Gaoxingyu Huang
- Key Laboratory of Structural Biology of Zhejiang Province Institute of Biology, Westlake Institute for Advanced Study School of Life Sciences Westlake University Hangzhou 310024 Zhejiang Province China
| | - Kun Wu
- Medical Research Center Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation Beijing Chao-Yang Hospital Capital Medical University Beijing 100020 China
| | - Jianlin Lei
- Technology Center for Protein Sciences Ministry of Education Key Laboratory of Protein Sciences School of Life Sciences Tsinghua University Beijing 100084 China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology Beijing Advanced Innovation Center for Structural Biology Tsinghua-Peking Joint Center for Life Science School of Life Sciences Tsinghua University Beijing 100084 China
| | - Nieng Yan
- Department of Molecular Biology Princeton University Princeton NJ 08544 USA
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19
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Structural Pharmacology of Voltage-Gated Sodium Channels. J Mol Biol 2021; 433:166967. [PMID: 33794261 DOI: 10.1016/j.jmb.2021.166967] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (NaV) channels initiate and propagate action potentials in excitable tissues to mediate key physiological processes including heart contraction and nervous system function. Accordingly, NaV channels are major targets for drugs, toxins and disease-causing mutations. Recent breakthroughs in cryo-electron microscopy have led to the visualization of human NaV1.1, NaV1.2, NaV1.4, NaV1.5 and NaV1.7 channel subtypes at high-resolution. These landmark studies have greatly advanced our structural understanding of channel architecture, ion selectivity, voltage-sensing, electromechanical coupling, fast inactivation, and the molecular basis underlying NaV channelopathies. NaV channel structures have also been increasingly determined in complex with toxin and small molecule modulators that target either the pore module or voltage sensor domains. These structural studies have provided new insights into the mechanisms of pharmacological action and opportunities for subtype-selective NaV channel drug design. This review will highlight the structural pharmacology of human NaV channels as well as the potential use of engineered and chimeric channels in future drug discovery efforts.
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20
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Nakajima T, Kaneko Y, Dharmawan T, Kurabayashi M. Role of the voltage sensor module in Na v domain IV on fast inactivation in sodium channelopathies: The implication of closed-state inactivation. Channels (Austin) 2020; 13:331-343. [PMID: 31357904 PMCID: PMC6713248 DOI: 10.1080/19336950.2019.1649521] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The segment 4 (S4) voltage sensor in voltage-gated sodium channels (Navs) have domain-specific functions, and the S4 segment in domain DIV (DIVS4) plays a key role in the activation and fast inactivation processes through the coupling of arginine residues in DIVS4 with residues of putative gating charge transfer center (pGCTC) in DIVS1-3. In addition, the first four arginine residues (R1-R4) in Nav DIVS4 have position-specific functions in the fast inactivation process, and mutations in these residues are associated with diverse phenotypes of Nav-related diseases (sodium channelopathies). R1 and R2 mutations commonly display a delayed fast inactivation, causing a gain-of-function, whereas R3 and R4 mutations commonly display a delayed recovery from inactivation and profound use-dependent current attenuation, causing a severe loss-of-function. In contrast, mutations of residues of pGCTC in Nav DIVS1-3 can also alter fast inactivation. Such alterations in fast inactivation may be caused by disrupted interactions of DIVS4 with DIVS1-3. Despite fast inactivation of Navs occurs from both the open-state (open-state inactivation; OSI) and closed state (closed-state inactivation; CSI), changes in CSI have received considerably less attention than those in OSI in the pathophysiology of sodium channelopathies. CSI can be altered by mutations of arginine residues in DIVS4 and residues of pGCTC in Navs, and altered CSI can be an underlying primary biophysical defect of sodium channelopathies. Therefore, CSI should receive focus in order to clarify the pathophysiology of sodium channelopathies.
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Affiliation(s)
- Tadashi Nakajima
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Yoshiaki Kaneko
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Tommy Dharmawan
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Masahiko Kurabayashi
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
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21
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Thull S, Neacsu C, O'Reilly AO, Bothe S, Hausmann R, Huth T, Meents J, Lampert A. Mechanism underlying hooked resurgent-like tail currents induced by an insecticide in human cardiac Nav1.5. Toxicol Appl Pharmacol 2020; 397:115010. [PMID: 32302602 DOI: 10.1016/j.taap.2020.115010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/12/2020] [Accepted: 04/14/2020] [Indexed: 01/02/2023]
Abstract
Voltage-gated sodium channels are responsible not only for the fast upstroke of the action potential, but they also modify cellular excitability via persistent and resurgent currents. Insecticides act via permanently opening sodium channels to immobilize the animals. Cellular recordings performed decades ago revealed distinctly hooked tail currents induced by these compounds. Here, we applied the classical type-II pyrethroid deltamethrin on human cardiac Nav1.5 and observed resurgent-like currents at very negative potentials in the absence of any pore-blocker, which resemble those hooked tail currents. We show that deltamethrin dramatically slows both fast inactivation and deactivation of Nav1.5 and thereby induces large persistent currents. Using the sea anemone toxin ATx-II as a tool to prevent all inactivation-related processes, resurgent-like currents were eliminated while persistent currents were preserved. Our experiments suggest that, in deltamethrin-modified channels, recovery from inactivation occurs faster than delayed deactivation, opening a brief window for sodium influx and leading to hooked, resurgent-like currents, in the absence of an open channel blocker. Thus, we now explain with pharmacological methods the biophysical gating changes underlying the deltamethrin induced hooked tail currents. SUMMARY: The pyrethroid deltamethrin induces hooked resurgent-like tail currents in human cardiac voltage-gated Nav1.5 channels. Using deltamethrin and ATx-II, we identify additional conducting channel states caused by a faster recovery from inactivation compared to the deltamethrin-induced delayed deactivation.
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Affiliation(s)
- Sarah Thull
- Institute of Physiology, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Cristian Neacsu
- Institut für Physiologie und Pathophysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitaetsstr. 17, 91054 Erlangen, Germany
| | - Andrias O O'Reilly
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Stefanie Bothe
- Institute of Physiology, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany; Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany
| | - Ralf Hausmann
- Institute of Clinical Pharmacology, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Tobias Huth
- Institut für Physiologie und Pathophysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitaetsstr. 17, 91054 Erlangen, Germany
| | - Jannis Meents
- Institute of Physiology, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany.
| | - Angelika Lampert
- Institute of Physiology, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany; Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany; Research Training Group 2415 ME3T, RWTH Aachen University, Aachen, Germany.
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22
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Catterall WA, Lenaeus MJ, Gamal El-Din TM. Structure and Pharmacology of Voltage-Gated Sodium and Calcium Channels. Annu Rev Pharmacol Toxicol 2020; 60:133-154. [PMID: 31537174 DOI: 10.1146/annurev-pharmtox-010818-021757] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Voltage-gated sodium and calcium channels are evolutionarily related transmembrane signaling proteins that initiate action potentials, neurotransmission, excitation-contraction coupling, and other physiological processes. Genetic or acquired dysfunction of these proteins causes numerous diseases, termed channelopathies, and sodium and calcium channels are the molecular targets for several major classes of drugs. Recent advances in the structural biology of these proteins using X-ray crystallography and cryo-electron microscopy have given new insights into the molecular basis for their function and pharmacology. Here we review this recent literature and integrate findings on sodium and calcium channels to reveal the structural basis for their voltage-dependent activation, fast and slow inactivation, ion conductance and selectivity, and complex pharmacology at the atomic level. We conclude with the theme that new understanding of the diseases and therapeutics of these channels will be derived from application of the emerging structural principles from these recent structural analyses.
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Affiliation(s)
- William A Catterall
- Department of Pharmacology and Division of General Internal Medicine, Department of Medicine, University of Washington, Seattle, Washington 98195, USA;
| | - Michael J Lenaeus
- Department of Pharmacology and Division of General Internal Medicine, Department of Medicine, University of Washington, Seattle, Washington 98195, USA;
| | - Tamer M Gamal El-Din
- Department of Pharmacology and Division of General Internal Medicine, Department of Medicine, University of Washington, Seattle, Washington 98195, USA;
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23
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Catacuzzeno L, Sforna L, Franciolini F. Voltage-dependent gating in K channels: experimental results and quantitative models. Pflugers Arch 2019; 472:27-47. [PMID: 31863286 DOI: 10.1007/s00424-019-02336-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/18/2022]
Abstract
Voltage-dependent K channels open and close in response to voltage changes across the cell membrane. This voltage dependence was postulated to depend on the presence of charged particles moving through the membrane in response to voltage changes. Recording of gating currents originating from the movement of these particles fully confirmed this hypothesis, and gave substantial experimental clues useful for the detailed understanding of the process. In the absence of structural information, the voltage-dependent gating was initially investigated using discrete Markov models, an approach only capable of providing a kinetic and thermodynamic comprehension of the process. The elucidation of the crystal structure of the first voltage-dependent channel brought in a dramatic change of pace in the understanding of channel gating, and in modeling the underlying processes. It was now possible to construct quantitative models using molecular dynamics, where all the interactions of each individual atom with the surroundings were taken into account, and its motion predicted by Newton's laws. Unfortunately, this modeling is computationally very demanding, and in spite of the advances in simulation procedures and computer technology, it is still limited in its predictive ability. To overcome these limitations, several groups have developed more macroscopic voltage gating models. Their approaches understandably require a number of approximations, which must however be physically well justified. One of these models, based on the description of the voltage sensor as a Brownian particle, that we have recently developed, is able to simultaneously describe the behavior of a single voltage sensor and to predict the macroscopic gating current originating from a population of sensors. The basics of this model are here described, and a typical application using the Kv1.2/2.1 chimera channel structure is also presented.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy.
| | - Luigi Sforna
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy.
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24
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Jiang D, Shi H, Tonggu L, Gamal El-Din TM, Lenaeus MJ, Zhao Y, Yoshioka C, Zheng N, Catterall WA. Structure of the Cardiac Sodium Channel. Cell 2019; 180:122-134.e10. [PMID: 31866066 DOI: 10.1016/j.cell.2019.11.041] [Citation(s) in RCA: 180] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/18/2019] [Accepted: 11/27/2019] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channel Nav1.5 generates cardiac action potentials and initiates the heartbeat. Here, we report structures of NaV1.5 at 3.2-3.5 Å resolution. NaV1.5 is distinguished from other sodium channels by a unique glycosyl moiety and loss of disulfide-bonding capability at the NaVβ subunit-interaction sites. The antiarrhythmic drug flecainide specifically targets the central cavity of the pore. The voltage sensors are partially activated, and the fast-inactivation gate is partially closed. Activation of the voltage sensor of Domain III allows binding of the isoleucine-phenylalanine-methionine (IFM) motif to the inactivation-gate receptor. Asp and Ala, in the selectivity motif DEKA, line the walls of the ion-selectivity filter, whereas Glu and Lys are in positions to accept and release Na+ ions via a charge-delocalization network. Arrhythmia mutation sites undergo large translocations during gating, providing a potential mechanism for pathogenic effects. Our results provide detailed insights into Nav1.5 structure, pharmacology, activation, inactivation, ion selectivity, and arrhythmias.
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Affiliation(s)
- Daohua Jiang
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Hui Shi
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Lige Tonggu
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | | | - Michael J Lenaeus
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Division of General Internal Medicine, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Yan Zhao
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Craig Yoshioka
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ning Zheng
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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25
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Hydrophobic gasket mutation produces gating pore currents in closed human voltage-gated proton channels. Proc Natl Acad Sci U S A 2019; 116:18951-18961. [PMID: 31462498 PMCID: PMC6754559 DOI: 10.1073/pnas.1905462116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A large family of membrane proteins, voltage-gated ion channels, regulate a vast array of physiological functions in essentially all life forms. How these molecules sense membrane potential and respond by creating ionic conduction is incompletely understood. The voltage sensors of these channels contain a “hydrophobic gasket,” a ring of hydrophobic amino acids near the center of the membrane, separating internal and external aqueous solutions. Although voltage-gated proton channels, HV1, resemble voltage-sensing domains of other channels, they differ fundamentally. On depolarization, HV1 conducts protons, whereas other voltage sensors open a physically distinct pore. We identify Val109, Phe150, Val177, and Val178 as the hHV1 hydrophobic gasket. Replacement with less hydrophobic amino acids accelerated channel opening and caused proton-selective leak through closed channels. The hydrophobic gasket (HG), a ring of hydrophobic amino acids in the voltage-sensing domain of most voltage-gated ion channels, forms a constriction between internal and external aqueous vestibules. Cationic Arg or Lys side chains lining the S4 helix move through this “gating pore” when the channel opens. S4 movement may occur during gating of the human voltage-gated proton channel, hHV1, but proton current flows through the same pore in open channels. Here, we replaced putative HG residues with less hydrophobic residues or acidic Asp. Substitution of individuals, pairs, or all 3 HG positions did not impair proton selectivity. Evidently, the HG does not act as a secondary selectivity filter. However, 2 unexpected functions of the HG in HV1 were discovered. Mutating HG residues independently accelerated channel opening and compromised the closed state. Mutants exhibited open–closed gating, but strikingly, at negative voltages where “normal” gating produces a nonconducting closed state, the channel leaked protons. Closed-channel proton current was smaller than open-channel current and was inhibited by 10 μM Zn2+. Extreme hyperpolarization produced a deeper closed state through a weakly voltage-dependent transition. We functionally identify the HG as Val109, Phe150, Val177, and Val178, which play a critical and exclusive role in preventing H+ influx through closed channels. Molecular dynamics simulations revealed enhanced mobility of Arg208 in mutants exhibiting H+ leak. Mutation of HG residues produces gating pore currents reminiscent of several channelopathies.
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26
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Wisedchaisri G, Tonggu L, McCord E, Gamal El-Din TM, Wang L, Zheng N, Catterall WA. Resting-State Structure and Gating Mechanism of a Voltage-Gated Sodium Channel. Cell 2019; 178:993-1003.e12. [PMID: 31353218 PMCID: PMC6688928 DOI: 10.1016/j.cell.2019.06.031] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/06/2019] [Accepted: 06/21/2019] [Indexed: 11/25/2022]
Abstract
Voltage-gated sodium (NaV) channels initiate action potentials in nerve, muscle, and other electrically excitable cells. The structural basis of voltage gating is uncertain because the resting state exists only at deeply negative membrane potentials. To stabilize the resting conformation, we inserted voltage-shifting mutations and introduced a disulfide crosslink in the VS of the ancestral bacterial sodium channel NaVAb. Here, we present a cryo-EM structure of the resting state and a complete voltage-dependent gating mechanism. The S4 segment of the VS is drawn intracellularly, with three gating charges passing through the transmembrane electric field. This movement forms an elbow connecting S4 to the S4-S5 linker, tightens the collar around the S6 activation gate, and prevents its opening. Our structure supports the classical "sliding helix" mechanism of voltage sensing and provides a complete gating mechanism for voltage sensor function, pore opening, and activation-gate closure based on high-resolution structures of a single sodium channel protein.
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Affiliation(s)
| | - Lige Tonggu
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Eedann McCord
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | | | - Liguo Wang
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Ning Zheng
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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27
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Xu L, Ding X, Wang T, Mou S, Sun H, Hou T. Voltage-gated sodium channels: structures, functions, and molecular modeling. Drug Discov Today 2019; 24:1389-1397. [PMID: 31129313 DOI: 10.1016/j.drudis.2019.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/02/2019] [Accepted: 05/17/2019] [Indexed: 10/26/2022]
Abstract
Voltage-gated sodium channels (VGSCs), formed by 24 transmembrane segments arranged into four domains, have a key role in the initiation and propagation of electrical signaling in excitable cells. VGSCs are involved in a variety of diseases, including epilepsy, cardiac arrhythmias, and neuropathic pain, and therefore have been regarded as appealing therapeutic targets for the development of anticonvulsant, antiarrhythmic, and local anesthetic drugs. In this review, we discuss recent advances in understanding the structures and biological functions of VGSCs. In addition, we systematically summarize eight pharmacologically distinct ligand-binding sites in VGSCs and representative isoform-selective VGSC modulators in clinical trials. Finally, we review studies on molecular modeling and computer-aided drug design (CADD) for VGSCs to help understanding of biological processes involving VGSCs.
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Affiliation(s)
- Lei Xu
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Xiaoqin Ding
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China
| | - Tianhu Wang
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shanzhi Mou
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Huiyong Sun
- Department of Medicinal Chemistry, School of Pharmacy, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
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28
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Dharmawan T, Nakajima T, Iizuka T, Tamura S, Matsui H, Kaneko Y, Kurabayashi M. Enhanced closed-state inactivation of mutant cardiac sodium channels (SCN5A N1541D and R1632C) through different mechanisms. J Mol Cell Cardiol 2019; 130:88-95. [PMID: 30935997 DOI: 10.1016/j.yjmcc.2019.03.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 03/27/2019] [Accepted: 03/29/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND SCN5A variants can be associated with overlapping phenotypes such as Brugada syndrome (BrS), sinus node dysfunction and supraventricular tachyarrhythmias. Our genetic screening of SCN5A in 65 consecutive BrS probands revealed two patients with overlapping phenotypes: one carried an SCN5A R1632C (in domain IV-segment 4), which we have previously reported, the other carried a novel SCN5A N1541D (in domain IV-segment 1). OBJECTIVE We sought to reveal whether or not these variants are associated with the same biophysical defects. METHODS Wild-type (WT) or mutant SCN5A was expressed in tsA201-cells, and whole-cell sodium currents (hNav1.5/INa) were recorded using patch-clamp techniques. RESULTS The N1541D-INa density, when assessed from a holding potential of -150 mV, was not different from WT-INa as with R1632C-INa, indicating that SCN5A N1541D did not cause trafficking defects. The steady-state inactivation curve of N1541D-INa was markedly shifted to hyperpolarizing potentials in comparison to WT-INa (V1/2-WT: -82.3 ± 0.9 mV, n = 15; N1541D: -108.8 ± 1.6 mV, n = 26, P < .01) as with R1632C-INa. Closed-state inactivation (CSI) was evaluated using prepulses of -90 mV for 1460 ms. Residual N1541D-INa and R1632C-INa were markedly reduced in comparison to WT-INa (WT: 63.8 ± 4.6%, n = 18; N1541D: 15.1 ± 2.3%, n = 19, P < .01 vs WT; R1632C: 5.3 ± 0.5%, n = 15, P < .01 vs WT). Entry into CSI of N1541D-INa was markedly accelerated, and that of R1632C-INa was weakly accelerated in comparison to WT-INa (tau-WT: 65.8 ± 7.4 ms, n = 18; N1541D: 13.7 ± 1.1 ms, n = 19, P < .01 vs WT; R1632C: 39.5 ± 2.9 ms, n = 15, P < .01 vs WT and N1541D). Although N1541D-INa recovered from closed-state fast inactivation at the same rate as WT-INa, R1632C-INa recovered very slowly (tau-WT: 1.90 ± 0.16 ms, n = 10; N1541D: 1.72 ± 0.12 ms, n = 10, P = .41 vs WT; R1632C: 53.0 ± 2.5 ms, n = 14, P < .01 vs WT and N1541D). CONCLUSIONS Both N1541D-INa and R1632C-INa exhibited marked enhancement of CSI, but through different mechanisms. The data provided a novel understanding of the mechanisms of CSI of INa. Clinically, the enhanced CSI of N1541D-INa leads to a severe loss-of-function of INa at voltages near the physiological resting membrane potential (~-90 mV) of cardiac myocytes; this can be attributable to the patient's phenotypic manifestations.
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Affiliation(s)
- Tommy Dharmawan
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Tadashi Nakajima
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
| | - Takashi Iizuka
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Shuntaro Tamura
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Hiroki Matsui
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi, Gunma, Japan
| | - Yoshiaki Kaneko
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Masahiko Kurabayashi
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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29
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Nastou KC, Batskinis MA, Litou ZI, Hamodrakas SJ, Iconomidou VA. Analysis of Single-Nucleotide Polymorphisms in Human Voltage-Gated Ion Channels. J Proteome Res 2019; 18:2310-2320. [DOI: 10.1021/acs.jproteome.9b00121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katerina C. Nastou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Michail A. Batskinis
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Zoi I. Litou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Stavros J. Hamodrakas
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Vassiliki A. Iconomidou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
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30
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Clairfeuille T, Cloake A, Infield DT, Llongueras JP, Arthur CP, Li ZR, Jian Y, Martin-Eauclaire MF, Bougis PE, Ciferri C, Ahern CA, Bosmans F, Hackos DH, Rohou A, Payandeh J. Structural basis of α-scorpion toxin action on Na v channels. Science 2019; 363:science.aav8573. [PMID: 30733386 DOI: 10.1126/science.aav8573] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023]
Abstract
Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling, but its mechanism remains poorly understood. Here we determined the structures of a eukaryotic Nav channel alone and in complex with a lethal α-scorpion toxin, AaH2, by electron microscopy, both at 3.5-angstrom resolution. AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state in which gating charge interactions bridge to the acidic intracellular carboxyl-terminal domain. In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery. Highlighting the polypharmacology of α-scorpion toxins, AaH2 also targets an unanticipated receptor site on VSD1 and a pore glycan adjacent to VSD4. Overall, this work provides key insights into fast inactivation, electromechanical coupling, and pathogenic mutations in Nav channels.
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Affiliation(s)
- Thomas Clairfeuille
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Alexander Cloake
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.,Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - José P Llongueras
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Zhong Rong Li
- Department of Biomolecular Resources, Genentech Inc., South San Francisco, CA, USA
| | - Yuwen Jian
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, LNC, UMR 7291, 13003 Marseille, France
| | - Claudio Ciferri
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium.
| | - David H Hackos
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
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31
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Kannan M, Vasan G, Pieribone VA. Optimizing Strategies for Developing Genetically Encoded Voltage Indicators. Front Cell Neurosci 2019; 13:53. [PMID: 30863283 PMCID: PMC6399427 DOI: 10.3389/fncel.2019.00053] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/04/2019] [Indexed: 01/23/2023] Open
Abstract
Genetically encoded optical indicators of neuronal activity enable unambiguous recordings of input-output activity patterns from identified cells in intact circuits. Among them, genetically encoded voltage indicators (GEVIs) offer additional advantages over calcium indicators as they are direct sensors of membrane potential and can adeptly report subthreshold events and hyperpolarization. Here, we outline the major GEVI designs and give an account of properties that need to be carefully optimized during indicator engineering. While designing the ideal GEVI, one should keep in mind aspects such as membrane localization, signal size, signal-to-noise ratio, kinetics and voltage dependence of optical responses. Using ArcLight and derivatives as prototypes, we delineate how a probe should be optimized for the former properties and developed along other areas in a need-based manner. Finally, we present an overview of the GEVI engineering process and lend an insight into their discovery, delivery and diagnosis.
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Affiliation(s)
- Madhuvanthi Kannan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Ganesh Vasan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Vincent A Pieribone
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Neuroscience, Yale School of Medicine, Yale University, New Haven, CT, United States
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32
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Okamura Y, Kawanabe A, Kawai T. Voltage-Sensing Phosphatases: Biophysics, Physiology, and Molecular Engineering. Physiol Rev 2019; 98:2097-2131. [PMID: 30067160 DOI: 10.1152/physrev.00056.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-sensing phosphatase (VSP) contains a voltage sensor domain (VSD) similar to that in voltage-gated ion channels, and a phosphoinositide phosphatase region similar to phosphatase and tensin homolog deleted on chromosome 10 (PTEN). The VSP gene is conserved from unicellular organisms to higher vertebrates. Membrane depolarization induces electrical driven conformational rearrangement in the VSD, which is translated into catalytic enzyme activity. Biophysical and structural characterization has revealed details of the mechanisms underlying the molecular functions of VSP. Coupling between the VSD and the enzyme is tight, such that enzyme activity is tuned in a graded fashion to the membrane voltage. Upon VSP activation, multiple species of phosphoinositides are simultaneously altered, and the profile of enzyme activity depends on the history of the membrane potential. VSPs have been the obvious candidate link between membrane potential and phosphoinositide regulation. However, patterns of voltage change regulating VSP in native cells remain largely unknown. This review addresses the current understanding of the biophysical biochemical properties of VSP and provides new insight into the proposed functions of VSP.
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Affiliation(s)
- Yasushi Okamura
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Akira Kawanabe
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Takafumi Kawai
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
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33
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Barro-Soria R. Epilepsy-associated mutations in the voltage sensor of KCNQ3 affect voltage dependence of channel opening. J Gen Physiol 2018; 151:247-257. [PMID: 30578330 PMCID: PMC6363412 DOI: 10.1085/jgp.201812221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/03/2018] [Indexed: 11/20/2022] Open
Abstract
One of the major factors known to cause neuronal hyperexcitability is malfunction of the potassium channels formed by KCNQ2 and KCNQ3. These channel subunits underlie the M current, which regulates neuronal excitability. Here, I investigate the molecular mechanisms by which epilepsy-associated mutations in the voltage sensor (S4) of KCNQ3 cause channel malfunction. Voltage clamp fluorometry reveals that the R230C mutation in KCNQ3 allows S4 movement but shifts the open/closed transition of the gate to very negative potentials. This results in the mutated channel remaining open throughout the physiological voltage range. Substitution of R230 with natural and unnatural amino acids indicates that the functional effect of the arginine residue at position 230 depends on both its positive charge and the size of its side chain. I find that KCNQ3-R230C is hard to close, but it is capable of being closed at strong negative voltages. I suggest that compounds that shift the voltage dependence of S4 activation to more positive potentials would promote gate closure and thus have therapeutic potential.
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Affiliation(s)
- Rene Barro-Soria
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL
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34
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Infield DT, Matulef K, Galpin JD, Lam K, Tajkhorshid E, Ahern CA, Valiyaveetil FI. Main-chain mutagenesis reveals intrahelical coupling in an ion channel voltage-sensor. Nat Commun 2018; 9:5055. [PMID: 30498243 PMCID: PMC6265297 DOI: 10.1038/s41467-018-07477-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 11/01/2018] [Indexed: 11/20/2022] Open
Abstract
Membrane proteins are universal signal decoders. The helical transmembrane segments of these proteins play central roles in sensory transduction, yet the mechanistic contributions of secondary structure remain unresolved. To investigate the role of main-chain hydrogen bonding on transmembrane function, we encoded amide-to-ester substitutions at sites throughout the S4 voltage-sensing segment of Shaker potassium channels, a region that undergoes rapid, voltage-driven movement during channel gating. Functional measurements of ester-harboring channels highlight a transitional region between α-helical and 310 segments where hydrogen bond removal is particularly disruptive to voltage-gating. Simulations of an active voltage sensor reveal that this region features a dynamic hydrogen bonding pattern and that its helical structure is reliant upon amide support. Overall, the data highlight the specialized role of main-chain chemistry in the mechanism of voltage-sensing; other catalytic transmembrane segments may enlist similar strategies in signal transduction mechanisms. The helical transmembrane segments of membrane proteins play central roles in sensory transduction but the mechanistic basis for their function remains unresolved. Here the authors identify regions in the S4 voltage-sensing segment of Shaker potassium channels where local helical structure is reliant upon backbone amide support.
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Affiliation(s)
- Daniel T Infield
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, 52242, USA
| | - Kimberly Matulef
- Program in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health Sciences University, Portland, 97239, OR, USA
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, 52242, USA
| | - Kin Lam
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Emad Tajkhorshid
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, 52242, USA.
| | - Francis I Valiyaveetil
- Program in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health Sciences University, Portland, 97239, OR, USA.
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35
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Gamal El-Din TM, Lenaeus MJ, Catterall WA. Structural and Functional Analysis of Sodium Channels Viewed from an Evolutionary Perspective. Handb Exp Pharmacol 2018; 246:53-72. [PMID: 29043505 DOI: 10.1007/164_2017_61] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels initiate and propagate action potentials in excitable cells. They respond to membrane depolarization through opening, followed by fast inactivation that terminates the sodium current. This ON-OFF behavior of voltage-gated sodium channels underlays the coding of information and its transmission from one location in the nervous system to another. In this review, we explore and compare structural and functional data from prokaryotic and eukaryotic channels to infer the effects of evolution on sodium channel structure and function.
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Affiliation(s)
- Tamer M Gamal El-Din
- Department of Pharmacology, University of Washington, Seattle, WA, 98195-7280, USA.
| | - Michael J Lenaeus
- Department of Pharmacology, University of Washington, Seattle, WA, 98195-7280, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA, 98195-7280, USA
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36
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The Role of Proton Transport in Gating Current in a Voltage Gated Ion Channel, as Shown by Quantum Calculations. SENSORS 2018; 18:s18093143. [PMID: 30231473 PMCID: PMC6163810 DOI: 10.3390/s18093143] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/05/2018] [Accepted: 09/12/2018] [Indexed: 11/25/2022]
Abstract
Over two-thirds of a century ago, Hodgkin and Huxley proposed the existence of voltage gated ion channels (VGICs) to carry Na+ and K+ ions across the cell membrane to create the nerve impulse, in response to depolarization of the membrane. The channels have multiple physiological roles, and play a central role in a wide variety of diseases when they malfunction. The first channel structure was found by MacKinnon and coworkers in 1998. Subsequently, the structure of a number of VGICs was determined in the open (ion conducting) state. This type of channel consists of four voltage sensing domains (VSDs), each formed from four transmembrane (TM) segments, plus a pore domain through which ions move. Understanding the gating mechanism (how the channel opens and closes) requires structures. One TM segment (S4) has an arginine in every third position, with one such segment per domain. It is usually assumed that these arginines are all ionized, and in the resting state are held toward the intracellular side of the membrane by voltage across the membrane. They are assumed to move outward (extracellular direction) when released by depolarization of this voltage, producing a capacitive gating current and opening the channel. We suggest alternate interpretations of the evidence that led to these models. Measured gating current is the total charge displacement of all atoms in the VSD; we propose that the prime, but not sole, contributor is proton motion, not displacement of the charges on the arginines of S4. It is known that the VSD can conduct protons. Quantum calculations on the Kv1.2 potassium channel VSD show how; the key is the amphoteric nature of the arginine side chain, which allows it to transfer a proton. This appears to be the first time the arginine side chain has had its amphoteric character considered. We have calculated one such proton transfer in detail: this proton starts from a tyrosine that can ionize, transferring to the NE of the third arginine on S4; that arginine’s NH then transfers a proton to a glutamate. The backbone remains static. A mutation predicted to affect the proton transfer has been qualitatively confirmed experimentally, from the change in the gating current-voltage curve. The total charge displacement in going from a normal closed potential of −70 mV across the membrane to 0 mV (open), is calculated to be approximately consistent with measured values, although the error limits on the calculation require caution in interpretation.
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37
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Pan X, Li Z, Zhou Q, Shen H, Wu K, Huang X, Chen J, Zhang J, Zhu X, Lei J, Xiong W, Gong H, Xiao B, Yan N. Structure of the human voltage-gated sodium channel Na v1.4 in complex with β1. Science 2018; 362:science.aau2486. [PMID: 30190309 DOI: 10.1126/science.aau2486] [Citation(s) in RCA: 263] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/20/2018] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (Nav) channels, which are responsible for action potential generation, are implicated in many human diseases. Despite decades of rigorous characterization, the lack of a structure of any human Nav channel has hampered mechanistic understanding. Here, we report the cryo-electron microscopy structure of the human Nav1.4-β1 complex at 3.2-Å resolution. Accurate model building was made for the pore domain, the voltage-sensing domains, and the β1 subunit, providing insight into the molecular basis for Na+ permeation and kinetic asymmetry of the four repeats. Structural analysis of reported functional residues and disease mutations corroborates an allosteric blocking mechanism for fast inactivation of Nav channels. The structure provides a path toward mechanistic investigation of Nav channels and drug discovery for Nav channelopathies.
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Affiliation(s)
- Xiaojing Pan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zhangqiang Li
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Huaizong Shen
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Kun Wu
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaoshuang Huang
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaofeng Chen
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juanrong Zhang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuechen Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xiong
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haipeng Gong
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Bailong Xiao
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
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38
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Hering S, Zangerl-Plessl EM, Beyl S, Hohaus A, Andranovits S, Timin EN. Calcium channel gating. Pflugers Arch 2018; 470:1291-1309. [PMID: 29951751 PMCID: PMC6096772 DOI: 10.1007/s00424-018-2163-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 05/28/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022]
Abstract
Tuned calcium entry through voltage-gated calcium channels is a key requirement for many cellular functions. This is ensured by channel gates which open during membrane depolarizations and seal the pore at rest. The gating process is determined by distinct sub-processes: movement of voltage-sensing domains (charged S4 segments) as well as opening and closure of S6 gates. Neutralization of S4 charges revealed that pore opening of CaV1.2 is triggered by a "gate releasing" movement of all four S4 segments with activation of IS4 (and IIIS4) being a rate-limiting stage. Segment IS4 additionally plays a crucial role in channel inactivation. Remarkably, S4 segments carrying only a single charged residue efficiently participate in gating. However, the complete set of S4 charges is required for stabilization of the open state. Voltage clamp fluorometry, the cryo-EM structure of a mammalian calcium channel, biophysical and pharmacological studies, and mathematical simulations have all contributed to a novel interpretation of the role of voltage sensors in channel opening, closure, and inactivation. We illustrate the role of the different methodologies in gating studies and discuss the key molecular events leading CaV channels to open and to close.
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Affiliation(s)
- S Hering
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
| | - E-M Zangerl-Plessl
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - S Beyl
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - A Hohaus
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - S Andranovits
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - E N Timin
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
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39
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Gating-induced large aqueous volumetric remodeling and aspartate tolerance in the voltage sensor domain of Shaker K + channels. Proc Natl Acad Sci U S A 2018; 115:8203-8208. [PMID: 30038023 DOI: 10.1073/pnas.1806578115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neurons encode electrical signals with critically tuned voltage-gated ion channels and enzymes. Dedicated voltage sensor domains (VSDs) in these membrane proteins activate coordinately with an unresolved structural change. Such change conveys the transmembrane translocation of four positively charged arginine side chains, the voltage-sensing residues (VSRs; R1-R4). Countercharges and lipid phosphohead groups likely stabilize these VSRs within the low-dielectric core of the protein. However, the role of hydration, a sign-independent charge stabilizer, remains unclear. We replaced all VSRs and their neighboring residues with negatively charged aspartates in a voltage-gated potassium channel. The ensuing mild functional effects indicate that hydration is also important in VSR stabilization. The voltage dependency of the VSR aspartate variants approached the expected arithmetic summation of charges at VSR positions, as if negative and positive side chains faced similar pathways. In contrast, aspartates introduced between R2 and R3 did not affect voltage dependence as if the side chains moved outside the electric field or together with it, undergoing a large displacement and volumetric remodeling. Accordingly, VSR performed osmotic work at both internal and external aqueous interfaces. Individual VSR contributions to volumetric works approached arithmetical additivity but were largely dissimilar. While R1 and R4 displaced small volumes, R2 and R3 volumetric works were massive and vectorially opposed, favoring large aqueous remodeling during VSD activation. These diverse volumetric works are, at least for R2 and R3, not compatible with VSR translocation across a unique stationary charge transfer center. Instead, VSRs may follow separated pathways across a fluctuating low-dielectric septum.
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40
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Abstract
A voltage change across a membrane protein moves charges or dipoles producing a gating current that is an electrical expression of a conformational change. Many membrane proteins sense the voltage across the membrane where they are inserted, and their function is affected by voltage changes. The voltage sensor consists of charges or dipoles that move in response to changes in the electric field, and their movement produces an electric current that has been called gating current. In the case of voltage-gated ion channels, the kinetic and steady-state properties of the gating charges provide information of conformational changes between closed states that are not visible when observing ionic currents only. In this Journal of General Physiology Milestone, the basic principles of voltage sensing and gating currents are presented, followed by a historical description of the recording of gating currents. The results of gating current recordings are then discussed in the context of structural changes in voltage-dependent membrane proteins and how these studies have provided new insights on gating mechanisms.
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Affiliation(s)
- Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL
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41
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Infield DT, Lee EEL, Galpin JD, Galles GD, Bezanilla F, Ahern CA. Replacing voltage sensor arginines with citrulline provides mechanistic insight into charge versus shape. J Gen Physiol 2018; 150:1017-1024. [PMID: 29866793 PMCID: PMC6028492 DOI: 10.1085/jgp.201812075] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 05/08/2018] [Indexed: 01/06/2023] Open
Abstract
Activation of voltage-gated channels results from the outward movement of arginine residues on the S4 segments. Infield et al. use in vivo nonsense suppression to replace Shaker's S4 arginine residues with citrulline and reveal that a positive charge is required on R4 for voltage-dependent deactivation. Voltage-dependent activation of voltage-gated cation channels results from the outward movement of arginine-bearing helices within proteinaceous voltage sensors. The voltage-sensing residues in potassium channels have been extensively characterized, but current functional approaches do not allow a distinction between the electrostatic and steric contributions of the arginine side chain. Here we use chemical misacylation and in vivo nonsense suppression to encode citrulline, a neutral and nearly isosteric analogue of arginine, into the voltage sensor of the Shaker potassium channel. We functionally characterize the engineered channels and compare them with those bearing conventional mutations at the same positions. We observe effects on both voltage sensitivity and gating kinetics, enabling dissection of the roles of residue structure versus positive charge in channel function. In some positions, substitution with citrulline causes mild effects on channel activation compared with natural mutations. In contrast, substitution of the fourth S4 arginine with citrulline causes substantial changes in the conductance–voltage relationship and the kinetics of the channel, which suggests that a positive charge is required at this position for efficient voltage sensor deactivation and channel closure. The encoding of citrulline is expected to enable enhanced precision for the study of arginine residues located in crowded transmembrane environments in other membrane proteins. In addition, the method may facilitate the study of citrullination in vivo.
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Affiliation(s)
- Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA
| | - Elizabeth E L Lee
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA
| | - Grace D Galles
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA
| | - Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL.,Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA .,Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA
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42
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DeCoursey TE. Voltage and pH sensing by the voltage-gated proton channel, H V1. J R Soc Interface 2018; 15:20180108. [PMID: 29643227 PMCID: PMC5938591 DOI: 10.1098/rsif.2018.0108] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/19/2018] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated proton channels are unique ion channels, membrane proteins that allow protons but no other ions to cross cell membranes. They are found in diverse species, from unicellular marine life to humans. In all cells, their function requires that they open and conduct current only under certain conditions, typically when the electrochemical gradient for protons is outwards. Consequently, these proteins behave like rectifiers, conducting protons out of cells. Their activity has electrical consequences and also changes the pH on both sides of the membrane. Here we summarize what is known about the way these proteins sense the membrane potential and the pH inside and outside the cell. Currently, it is hypothesized that membrane potential is sensed by permanently charged arginines (with very high pKa) within the protein, which results in parts of the protein moving to produce a conduction pathway. The mechanism of pH sensing appears to involve titratable side chains of particular amino acids. For this purpose their pKa needs to be within the operational pH range. We propose a 'counter-charge' model for pH sensing in which electrostatic interactions within the protein are selectively disrupted by protonation of internally or externally accessible groups.
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Affiliation(s)
- Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, 1750 West Harrison, Chicago, IL 60612, USA
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43
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Zhao F, Jin W, Ma L, Zhang JY, Wang JL, Zhang JH, Song YB. Investigation of the selectivity of one type of small-molecule inhibitor for three Na v channel isoforms based on the method of computer simulation. J Biomol Struct Dyn 2018; 37:702-713. [PMID: 29448911 DOI: 10.1080/07391102.2018.1438921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Voltage-gated sodium (Nav) channels play a pivotal role for the changes in membrane potential and belong to large membrane proteins that compose four voltage sensor domains (VSD1-4). In this study, we describe the binding mode and selectivity of one of the aryl sulfonamide sodium channel inhibitors, PF-04856264, for the VSD4s in Nav1.4, Nav1.5 and Nav1.7, respectively, through molecular dynamics simulation and enhanced post-dynamics analyses. Our results show that there are three binding site regions (BSR1-3) in the combination of the ligand and receptors, of which BSR1 and BSR3 contribute to the selectivity and affinity of the ligand to the receptor. What's more, the 39th residue (Y39 in VSD4hNav1.4/ VSD4hNav1.7 and A39 in VSD4hNav1.5) and N42 in BSR1, the 84th residue (L84 in VSD4hNav1.4, T84 in VSD4hNav1.5, and M84 in VSD4hNav1.7) in BSR2 and the conserved positive charged residues in BSR3 have major contributions to the interaction between the ligand and receptor. Further analysis reveals that if the 39th residue has a benzene ring structure, the connection of BSR1 and the ligand would be much stronger through π-stacking interaction. On the other hand, the strength and number of the hydrogen bonds formed by the ligand and the conserved arginines on S4 determine the contribution of BSR3 to the total free binding energy. We anticipate this study pave the way for the design of more effective and safe treatment for pain that selectively target Nav1.7.
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Affiliation(s)
- Fan Zhao
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Wei Jin
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Lin Ma
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Jian-Ye Zhang
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Jin-Long Wang
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Jing-Hai Zhang
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
| | - Yong-Bo Song
- a School of Life Science and Bio-pharmaceutics , Shenyang Pharmaceutical University , 103 Wenhua Road, Shenyang 110016 , China
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44
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Abstract
Voltage-gated sodium (Na+) channels are expressed in virtually all electrically excitable tissues and are essential for muscle contraction and the conduction of impulses within the peripheral and central nervous systems. Genetic disorders that disrupt the function of these channels produce an array of Na+ channelopathies resulting in neuronal impairment, chronic pain, neuromuscular pathologies, and cardiac arrhythmias. Because of their importance to the conduction of electrical signals, Na+ channels are the target of a wide variety of local anesthetic, antiarrhythmic, anticonvulsant, and antidepressant drugs. The voltage-gated family of Na+ channels is composed of α-subunits that encode for the voltage sensor domains and the Na+-selective permeation pore. In vivo, Na+ channel α-subunits are associated with one or more accessory β-subunits (β1-β4) that regulate gating properties, trafficking, and cell-surface expression of the channels. The permeation pore of Na+ channels is divided in two parts: the outer mouth of the pore is the site of the ion selectivity filter, while the inner cytoplasmic pore serves as the channel activation gate. The cytoplasmic lining of the permeation pore is formed by the S6 segments that include highly conserved aromatic amino acids important for drug binding. These residues are believed to undergo voltage-dependent conformational changes that alter drug binding as the channels cycle through the closed, open, and inactivated states. The purpose of this chapter is to broadly review the mechanisms of Na+ channel gating and the models used to describe drug binding and Na+ channel inhibition.
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Affiliation(s)
- M E O'Leary
- Cooper Medical School of Rowan University, Camden, NJ, USA
| | - M Chahine
- CERVO Brain Research Center, Institut universitaire en santé mentale de Québec, Quebec City, QC, Canada.
- Department of Medicine, Université Laval, Quebec City, QC, Canada.
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45
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Abstract
Voltage-gated sodium channels belong to the superfamily of voltage-gated cation channels. Their structure is based on domains comprising a voltage sensor domain (S1-S4 segments) and a pore domain (S5-S6 segments). Mutations in positively charged residues of the S4 segments may allow protons or cations to pass directly through the gating pore constriction of the voltage sensor domain; these anomalous currents are referred to as gating pore or omega (ω) currents. In the skeletal muscle disorder hypokalemic periodic paralysis, and in arrhythmic dilated cardiomyopathy, inherited mutations of S4 arginine residues promote omega currents that have been shown to be a contributing factor in the pathogenesis of these sodium channel disorders. Characterization of gating pore currents in these channelopathies and with artificial mutations has been possible by measuring the voltage-dependence and selectivity of these leak currents. The basis of gating pore currents and the structural basis of S4 movement through the gating pore has also been studied extensively with molecular dynamics. These simulations have provided valuable insight into the nature of S4 translocation and the physical basis for the effects of mutations that promote permeation of protons or cations through the gating pore.
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Affiliation(s)
- J R Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA.
| | - A Moreau
- Institut NeuroMyogene, ENS de Lyon, Site MONOD, Lyon, France
| | - L Delemotte
- Science for Life Laboratory, Department of Physics, KTH Royal Institute of Technology, Box 1031, 171 21, Solna, Sweden
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46
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Na V Channels: Assaying Biosynthesis, Trafficking, Function. Methods Mol Biol 2017. [PMID: 29264805 DOI: 10.1007/978-1-4939-7553-2_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Integral to the cell surface is channels, pumps, and exchanger proteins that facilitate the movement of ions across the membrane. Ion channels facilitate the passive movement of ions down an electrochemical gradient. Ion pumps actively use energy to actively translocate ions, often against concentration or voltage gradients, while ion exchangers utilize energy to couple the transport of different ion species such that one ion moves down its gradient and the released free energy is used to drive the movement of a different ion against its electrochemical gradient. Some ion pumps and exchangers may be electrogenic, i.e., the ion transport they support is not electrically neutral and generates a current. Functions of these pore-forming membrane proteins include the establishment of membrane potentials, gating of ions flows across the cell membrane to elicit action potentials and other electrical signals, as well as the regulation of cell volumes. The major forms of ion channels include voltage-, ligand-, and signal-gated channels. In this review, we describe mammalian voltage dependent Na (NaV) channels.
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47
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DeCoursey TE, Morgan D, Musset B, Cherny VV. Insights into the structure and function of HV1 from a meta-analysis of mutation studies. J Gen Physiol 2017; 148:97-118. [PMID: 27481712 PMCID: PMC4969798 DOI: 10.1085/jgp.201611619] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/30/2016] [Indexed: 01/26/2023] Open
Abstract
The voltage-gated proton channel (HV1) is a widely distributed, proton-specific ion channel with unique properties. Since 2006, when genes for HV1 were identified, a vast array of mutations have been generated and characterized. Accessing this potentially useful resource is hindered, however, by the sheer number of mutations and interspecies differences in amino acid numbering. This review organizes all existing information in a logical manner to allow swift identification of studies that have characterized any particular mutation. Although much can be gained from this meta-analysis, important questions about the inner workings of HV1 await future revelation.
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Affiliation(s)
- Thomas E DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
| | - Deri Morgan
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
| | - Boris Musset
- Institut für Physiologie, PMU Klinikum Nürnberg, 90419 Nürnberg, Germany
| | - Vladimir V Cherny
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
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48
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Mahling R, Kilpatrick AM, Shea MA. Backbone resonance assignments of complexes of human voltage-dependent sodium channel Na V1.2 IQ motif peptide bound to apo calmodulin and to the C-domain fragment of apo calmodulin. BIOMOLECULAR NMR ASSIGNMENTS 2017; 11:297-303. [PMID: 28823028 PMCID: PMC5791537 DOI: 10.1007/s12104-017-9767-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/12/2017] [Indexed: 06/07/2023]
Abstract
Human voltage-gated sodium channel NaV1.2 has a single pore-forming α-subunit and two transmembrane β-subunits. Expressed primarily in the brain, NaV1.2 is critical for initiation and propagation of action potentials. Milliseconds after the pore opens, sodium influx is terminated by inactivation processes mediated by regulatory proteins including calmodulin (CaM). Both calcium-free (apo) CaM and calcium-saturated CaM bind tightly to an IQ motif in the C-terminal tail of the α-subunit. Our thermodynamic studies and solution structure (2KXW) of a C-domain fragment of apo 13C,15N- CaM (CaMC) bound to an unlabeled peptide with the sequence of rat NaV1.2 IQ motif showed that apo CaMC (a) was necessary and sufficient for binding, and (b) bound more favorably than calcium-saturated CaMC. However, we could not monitor the NaV1.2 residues directly, and no structure of full-length CaM (including the N-domain of CaM (CaMN)) was determined. To distinguish contributions of CaMN and CaMC, we used solution NMR spectroscopy to assign the backbone resonances of a complex containing a 13C,15N-labeled peptide with the sequence of human NaV1.2 IQ motif (NaV1.2IQp) bound to apo 13C,15N-CaM or apo 13C,15N-CaMC. Comparing the assignments of apo CaM in complex with NaV1.2IQp to those of free apo CaM showed that residues within CaMC were significantly perturbed, while residues within CaMN were essentially unchanged. The chemical shifts of residues in NaV1.2IQp and in the C-domain of CaM were nearly identical regardless of whether CaMN was covalently linked to CaMC. This suggests that CaMN does not influence apo CaM binding to NaV1.2IQp.
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Affiliation(s)
- Ryan Mahling
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242-1109, USA
| | - Adina M Kilpatrick
- Department of Physics and Astronomy, Drake University, Des Moines, IA, 50311-4516, USA
| | - Madeline A Shea
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242-1109, USA.
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49
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Catterall WA. Forty Years of Sodium Channels: Structure, Function, Pharmacology, and Epilepsy. Neurochem Res 2017; 42:2495-2504. [PMID: 28589518 PMCID: PMC5693772 DOI: 10.1007/s11064-017-2314-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 11/24/2022]
Abstract
Voltage-gated sodium channels initiate action potentials in brain neurons. In the 1970s, much was known about the function of sodium channels from measurements of ionic currents using the voltage clamp method, but there was no information about the sodium channel molecules themselves. As a postdoctoral fellow and staff scientist at the National Institutes of Health, I developed neurotoxins as molecular probes of sodium channels in cultured neuroblastoma cells. During those years, Bruce Ransom and I crossed paths as members of the laboratories of Marshall Nirenberg and Philip Nelson and shared insights about sodium channels in neuroblastoma cells from my work and electrical excitability and synaptic transmission in cultured spinal cord neurons from Bruce's pioneering electrophysiological studies. When I established my laboratory at the University of Washington in 1977, my colleagues and I used those neurotoxins to identify the protein subunits of sodium channels, purify them, and reconstitute their ion conductance activity in pure form. Subsequent studies identified the molecular basis for the main functions of sodium channels-voltage-dependent activation, rapid and selective ion conductance, and fast inactivation. Bruce Ransom and I re-connected in the 1990s, as ski buddies at the Winter Conference on Brain Research and as faculty colleagues at the University of Washington when Bruce became our founding Chair of Neurology and provided visionary leadership of that department. In the past decade my work on sodium channels has evolved into structural biology. Molecular modeling and X-ray crystallographic studies have given new views of sodium channel function at atomic resolution. Sodium channels are also the molecular targets for genetic diseases, including Dravet Syndrome, an intractable pediatric epilepsy disorder with major co-morbidities of cognitive deficit, autistic-like behaviors, and premature death that is caused by loss-of-function mutations in the brain sodium channel NaV1.1. Our work on a mouse genetic model of this disease has shown that its multi-faceted pathophysiology and co-morbidities derive from selective loss of electrical excitability and action potential firing in GABAergic inhibitory neurons, which disinhibits neural circuits throughout the brain and leads directly to the epilepsy, premature death and complex co-morbidities of this disease. It has been rewarding for me to use our developing knowledge of sodium channels to help understand the pathophysiology and to suggest potential therapeutic approaches for this devastating childhood disease.
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Affiliation(s)
- William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA, 98195-7280, USA.
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KCNE1 and KCNE3 modulate KCNQ1 channels by affecting different gating transitions. Proc Natl Acad Sci U S A 2017; 114:E7367-E7376. [PMID: 28808020 DOI: 10.1073/pnas.1710335114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
KCNE β-subunits assemble with and modulate the properties of voltage-gated K+ channels. In the heart, KCNE1 associates with the α-subunit KCNQ1 to generate the slowly activating, voltage-dependent potassium current (IKs) in the heart that controls the repolarization phase of cardiac action potentials. By contrast, in epithelial cells from the colon, stomach, and kidney, KCNE3 coassembles with KCNQ1 to form K+ channels that are voltage-independent K+ channels in the physiological voltage range and important for controlling water and salt secretion and absorption. How KCNE1 and KCNE3 subunits modify KCNQ1 channel gating so differently is largely unknown. Here, we use voltage clamp fluorometry to determine how KCNE1 and KCNE3 affect the voltage sensor and the gate of KCNQ1. By separating S4 movement and gate opening by mutations or phosphatidylinositol 4,5-bisphosphate depletion, we show that KCNE1 affects both the S4 movement and the gate, whereas KCNE3 affects the S4 movement and only affects the gate in KCNQ1 if an intact S4-to-gate coupling is present. Further, we show that a triple mutation in the middle of the transmembrane (TM) segment of KCNE3 introduces KCNE1-like effects on the second S4 movement and the gate. In addition, we show that differences in two residues at the external end of the KCNE TM segments underlie differences in the effects of the different KCNEs on the first S4 movement and the voltage sensor-to-gate coupling.
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