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Chen H, Xia Z, Dong J, Huang B, Zhang J, Zhou F, Yan R, Shi Y, Gong J, Jiang J, Huang Z, Jiang D. Structural mechanism of voltage-gated sodium channel slow inactivation. Nat Commun 2024; 15:3691. [PMID: 38693179 PMCID: PMC11063143 DOI: 10.1038/s41467-024-48125-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 04/17/2024] [Indexed: 05/03/2024] Open
Abstract
Voltage-gated sodium (NaV) channels mediate a plethora of electrical activities. NaV channels govern cellular excitability in response to depolarizing stimuli. Inactivation is an intrinsic property of NaV channels that regulates cellular excitability by controlling the channel availability. The fast inactivation, mediated by the Ile-Phe-Met (IFM) motif and the N-terminal helix (N-helix), has been well-characterized. However, the molecular mechanism underlying NaV channel slow inactivation remains elusive. Here, we demonstrate that the removal of the N-helix of NaVEh (NaVEhΔN) results in a slow-inactivated channel, and present cryo-EM structure of NaVEhΔN in a potential slow-inactivated state. The structure features a closed activation gate and a dilated selectivity filter (SF), indicating that the upper SF and the inner gate could serve as a gate for slow inactivation. In comparison to the NaVEh structure, NaVEhΔN undergoes marked conformational shifts on the intracellular side. Together, our results provide important mechanistic insights into NaV channel slow inactivation.
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Affiliation(s)
- Huiwen Chen
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhanyi Xia
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Jie Dong
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Bo Huang
- Beijing StoneWise Technology Co Ltd., 15 Haidian street, Haidian district, Beijing, China
| | - Jiangtao Zhang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Feng Zhou
- Beijing StoneWise Technology Co Ltd., 15 Haidian street, Haidian district, Beijing, China
| | - Rui Yan
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yiqiang Shi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jianke Gong
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juquan Jiang
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China.
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, China.
| | - Daohua Jiang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
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Eltokhi A, Lundstrom BN, Li J, Zweifel LS, Catterall WA, Gamal El-Din TM. Pathogenic gating pore current conducted by autism-related mutations in the Na V1.2 brain sodium channel. Proc Natl Acad Sci U S A 2024; 121:e2317769121. [PMID: 38564633 PMCID: PMC11009634 DOI: 10.1073/pnas.2317769121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by social and communication deficits and repetitive behaviors. The genetic heterogeneity of ASD presents a challenge to the development of an effective treatment targeting the underlying molecular defects. ASD gating charge mutations in the KCNQ/KV7 potassium channel cause gating pore currents (Igp) and impair action potential (AP) firing of dopaminergic neurons in brain slices. Here, we investigated ASD gating charge mutations of the voltage-gated SCN2A/NaV1.2 brain sodium channel, which ranked high among the ion channel genes with mutations in individuals with ASD. Our results show that ASD mutations in the gating charges R2 in Domain-II (R853Q), and R1 (R1626Q) and R2 (R1629H) in Domain-IV of NaV1.2 caused Igp in the resting state of ~0.1% of the amplitude of central pore current. The R1626Q mutant also caused significant changes in the voltage dependence of fast inactivation, and the R1629H mutant conducted proton-selective Igp. These potentially pathogenic Igp were exacerbated by the absence of the extracellular Mg2+ and Ca2+. In silico simulation of the effects of these mutations in a conductance-based single-compartment cortical neuron model suggests that the inward Igp reduces the time to peak for the first AP in a train, increases AP rates during a train of stimuli, and reduces the interstimulus interval between consecutive APs, consistent with increased neural excitability and altered input/output relationships. Understanding this common pathophysiological mechanism among different voltage-gated ion channels at the circuit level will give insights into the underlying mechanisms of ASD.
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Affiliation(s)
- Ahmed Eltokhi
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | - Brian Nils Lundstrom
- Department of Neurology in the Division of Epilepsy, Mayo Clinic, Rochester, MN55905
| | - Jin Li
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | - Larry S. Zweifel
- Department of Pharmacology, University of Washington, Seattle, WA98195
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA98195
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Glazer AM, Yang T, Li B, Page D, Fouda M, Wada Y, Lancaster MC, O’Neill MJ, Muhammad A, Gao X, Ackerman MJ, Sanatani S, Ruben PC, Roden DM. Multifocal Ectopic Purkinje Premature Contractions due to neutralization of an SCN5A negative charge: structural insights into the gating pore hypothesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.13.580021. [PMID: 38405820 PMCID: PMC10888965 DOI: 10.1101/2024.02.13.580021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Background We identified a novel SCN5A variant, E171Q, in a neonate with very frequent ectopy and reduced ejection fraction which normalized after arrhythmia suppression by flecainide. This clinical picture is consistent with multifocal ectopic Purkinje-related premature contractions (MEPPC). Most previous reports of MEPPC have implicated SCN5A variants such as R222Q that neutralize positive charges in the S4 voltage sensor helix of the channel protein NaV1.5 and generate a gating pore current. Methods and Results E171 is a highly conserved negatively-charged residue located in the S2 transmembrane helix of NaV1.5 domain I. E171 is a key component of the Gating Charge Transfer Center, a region thought to be critical for normal movement of the S4 voltage sensor helix. We used heterologous expression, CRISPR-edited induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), and molecular dynamics simulations to demonstrate that E171Q generates a gating pore current, which was suppressed by a low concentration of flecainide (IC50 = 0.71±0.07 µM). R222Q shifts voltage dependence of activation and inactivation in a negative direction but we observed positive shifts with E171Q. E171Q iPSC-CMs demonstrated abnormal spontaneous activity and prolonged action potentials. Molecular dynamics simulations revealed that both R222Q and E171Q proteins generate a water-filled permeation pathway that underlies generation of the gating pore current. Conclusion Previously identified MEPPC-associated variants that create gating pore currents are located in positively-charged residues in the S4 voltage sensor and generate negative shifts in the voltage dependence of activation and inactivation. We demonstrate that neutralizing a negatively charged S2 helix residue in the Gating Charge Transfer Center generates positive shifts but also create a gating pore pathway. These findings implicate the gating pore pathway as the primary functional and structural determinant of MEPPC and widen the spectrum of variants that are associated with gating pore-related disease in voltage-gated ion channels.
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Affiliation(s)
| | - Tao Yang
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bian Li
- Vanderbilt University Medical Center, Nashville, TN, USA
- Current address: Regeneron Pharmaceuticals Inc., Tarrytown NY, USA. Bian Li contributed to this article as an employee of Vanderbilt University Medical Center and the views expressed do not necessarily represent the views of Regeneron Pharmaceuticals Inc
| | - Dana Page
- Simon Fraser University, Burnaby, BC, Canada
| | | | - Yuko Wada
- Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | | | - Xiaozhi Gao
- Mayo Clinic College of Medicine and Science, Mayo Foundation, Rochester, MN, USA
| | - Michael J. Ackerman
- Mayo Clinic College of Medicine and Science, Mayo Foundation, Rochester, MN, USA
| | | | | | - Dan M. Roden
- Vanderbilt University Medical Center, Nashville, TN, USA
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Liu Z, Wang F, Yuan H, Tian F, Yang C, Hu F, Liu Y, Tang M, Ping M, Kang C, Luo T, Yang G, Hu M, Gao Z, Li P. An LQT2-related mutation in the voltage-sensing domain is involved in switching the gating polarity of hERG. BMC Biol 2024; 22:29. [PMID: 38317233 DOI: 10.1186/s12915-024-01833-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 01/23/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Cyclic Nucleotide-Binding Domain (CNBD)-family channels display distinct voltage-sensing properties despite sharing sequence and structural similarity. For example, the human Ether-a-go-go Related Gene (hERG) channel and the Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channel share high amino acid sequence similarity and identical domain structures. hERG conducts outward current and is activated by positive membrane potentials (depolarization), whereas HCN conducts inward current and is activated by negative membrane potentials (hyperpolarization). The structural basis for the "opposite" voltage-sensing properties of hERG and HCN remains unknown. RESULTS We found the voltage-sensing domain (VSD) involves in modulating the gating polarity of hERG. We identified that a long-QT syndrome type 2-related mutation within the VSD, K525N, mediated an inwardly rectifying non-deactivating current, perturbing the channel closure, but sparing the open state and inactivated state. K525N rescued the current of a non-functional mutation in the pore helix region (F627Y) of hERG. K525N&F627Y switched hERG into a hyperpolarization-activated channel. The reactivated inward current induced by hyperpolarization mediated by K525N&F627Y can be inhibited by E-4031 and dofetilide quite well. Moreover, we report an extracellular interaction between the S1 helix and the S5-P region is crucial for modulating the gating polarity. The alanine substitution of several residues in this region (F431A, C566A, I607A, and Y611A) impaired the inward current of K525N&F627Y. CONCLUSIONS Our data provide evidence that a potential cooperation mechanism in the extracellular vestibule of the VSD and the PD would determine the gating polarity in hERG.
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Affiliation(s)
- Zhipei Liu
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Feng Wang
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
| | - Hui Yuan
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
| | - Fuyun Tian
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Chuanyan Yang
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Fei Hu
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yiyao Liu
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
| | - Meiqin Tang
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Meixuan Ping
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunlan Kang
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Ting Luo
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- School of Pharmaceutical Sciences, Guizhou Medical University, Guiyang, 550025, China
| | - Guimei Yang
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
| | - Mei Hu
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China
- Pharmacology Laboratory, Zhongshan Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Zhongshan, 528401, China
| | - Zhaobing Gao
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China.
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China.
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Ping Li
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China.
- Zhongshan Institute for Drug Discovery, Zhongshan, 528400, China.
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Shen R, Roux B, Perozo E. Anionic omega currents from single countercharge mutants in the voltage-sensing domain of Ci-VSP. J Gen Physiol 2024; 156:e202213311. [PMID: 38019193 PMCID: PMC10686229 DOI: 10.1085/jgp.202213311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/08/2023] [Accepted: 10/30/2023] [Indexed: 11/30/2023] Open
Abstract
The S4 segment of voltage-sensing domains (VSDs) directly responds to voltage changes by reorienting within the electric field as a permion. A narrow hydrophobic "gasket" or charge transfer center at the core of most VSDs focuses the electric field into a narrow region and catalyzes the sequential and reversible translocation of S4 positive gating charge residues across the electric field while preventing the permeation of physiological ions. Mutating specific S4 gating charges can cause ionic leak currents through the VSDs. These gating pores or omega currents play important pathophysiological roles in many diseases of excitability. Here, we show that mutating D129, a key countercharge residue in the Ciona intestinalis voltage-sensing phosphatase (Ci-VSP), leads to the generation of unique anionic omega currents. Neutralizing D129 causes a dramatic positive shift of activation, facilitates the formation of a continuous water path through the VSD, and creates a positive electrostatic potential landscape inside the VSD that contributes to its unique anionic selectivity. Increasing the population or dwell time of the conducting state by a high external pH or an engineered Cd2+ bridge markedly increases the current magnitude. Our findings uncover a new role of countercharge residues in the impermeable VSD of Ci-VSP and offer insights into mechanisms of the conduction of anionic omega currents linked to countercharge residue mutations.
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Affiliation(s)
- Rong Shen
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Eduardo Perozo
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
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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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Eltokhi A, Catterall WA, Gamal El-Din TM. Cell-cycle arrest at the G1/S boundary enhances transient voltage-gated ion channel expression in human and insect cells. CELL REPORTS METHODS 2023; 3:100559. [PMID: 37751687 PMCID: PMC10545908 DOI: 10.1016/j.crmeth.2023.100559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/01/2023] [Accepted: 07/20/2023] [Indexed: 09/28/2023]
Abstract
Heterologous expression of recombinant ion channel subunits in cell lines is often limited by the presence of a low number of channels at the cell surface level. Here, we introduce a combination of two techniques: viral expression using the baculovirus system plus cell-cycle arrest at the G1/S boundary using either thymidine or hydroxyurea. This method achieved a manifold increase in the peak current density of expressed ion channels compared with the classical liposome-mediated transfection methods. The enhanced ionic current was accompanied by an increase in the density of gating charges, confirming that the increased yield of protein and ionic current reflects the functional localization of channels in the plasma membrane. This modified method of viral expression coordinated with the cell cycle arrest will pave the way to better decipher the structure and function of ion channels and their association with ion channelopathies.
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Affiliation(s)
- Ahmed Eltokhi
- 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
| | - Tamer M Gamal El-Din
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA.
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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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Calloe K, Magnusson HBD, Lildballe DL, Christiansen MK, Jensen HK. Multifocal ectopic purkinje-related premature contractions and related cardiomyopathy. Front Cardiovasc Med 2023; 10:1179018. [PMID: 37600057 PMCID: PMC10436533 DOI: 10.3389/fcvm.2023.1179018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
In the past 20 years, genetic variants in SCN5A encoding the cardiac voltage-gated sodium channel Nav1.5 have been linked to a range of inherited cardiac arrhythmias: variants resulting in loss-of-function of Nav1.5 have been linked to sick sinus syndrome, atrial stand still, atrial fibrillation (AF) impaired pulse generation, progressive and non-progressive conduction defects, the Brugada Syndrome (BrS), and sudden cardiac death. SCN5A variants causing increased sodium current during the plateau phase of the cardiac action potential is associated with Long QT Syndrome type 3 (LQTS3), Torsade de Pointes ventricular tachycardia and SCD. Recently, gain-of-function variants have been linked to complex electrical phenotypes, such as the Multifocal Ectopic Purkinje-related Premature Contractions (MEPPC) syndrome. MEPPC is a rare condition characterized by a high burden of premature atrial contractions (PACs) and/or premature ventricular contractions (PVCs) often accompanied by dilated cardiomyopathy (DCM). MEPPC is inherited in an autosomal dominant fashion with an almost complete penetrance. The onset is often in childhood. The link between SCN5A variants, MEPPC and DCM is currently not well understood, but amino acid substitutions resulting in gain-of-function of Nav1.5 or introduction of gating pore currents potentially play an important role. DCM patients with a MEPPC phenotype respond relatively poorly to standard heart failure medical therapy and catheter ablation as the PVCs originate from all parts of the fascicular Purkinje fiber network. Class 1c sodium channel inhibitors, notably flecainide, have a remarkable positive effect on the ectopic burden and the associated cardiomyopathy. This highlights the importance of genetic screening of DCM patients to identify patients with SCN5A variants associated with MEPPC. Here we review the MEPPC phenotype, MEPPC-SCN5A associated variants, and pathogenesis as well as treatment options.
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Affiliation(s)
- Kirstine Calloe
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Helena B. D. Magnusson
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | | | - Henrik Kjærulf Jensen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Irie K, Oda Y, Sumikama T, Oshima A, Fujiyoshi Y. The structural basis of divalent cation block in a tetrameric prokaryotic sodium channel. Nat Commun 2023; 14:4236. [PMID: 37454189 PMCID: PMC10349818 DOI: 10.1038/s41467-023-39987-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
Divalent cation block is observed in various tetrameric ion channels. For blocking, a divalent cation is thought to bind in the ion pathway of the channel, but such block has not yet been directly observed. So, the behaviour of these blocking divalent cations remains still uncertain. Here, we elucidated the mechanism of the divalent cation block by reproducing the blocking effect into NavAb, a well-studied tetrameric sodium channel. Our crystal structures of NavAb mutants show that the mutations increasing the hydrophilicity of the inner vestibule of the pore domain enable a divalent cation to stack on the ion pathway. Furthermore, non-equilibrium molecular dynamics simulation showed that the stacking calcium ion repel sodium ion at the bottom of the selectivity filter. These results suggest the primary process of the divalent cation block mechanism in tetrameric cation channels.
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Affiliation(s)
- Katsumasa Irie
- Department of Biophysical Chemistry, School of Pharmaceutical Sciences, Wakayama Medical University, 25-1, Shichibancho, Wakayama, 640-8156, Japan.
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan.
| | - Yoshinori Oda
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
| | - Takashi Sumikama
- PRESTO, JST, Kawaguchi, 332-0012, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, 920-1192, Japan
| | - Atsunori Oshima
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
- Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
- Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Gifu, 501-11193, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Laboratory (CeSPL), Advanced Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, Tokyo, 113-8510, Japan
- CeSPIA Inc., 2-1-1, Otemachi, Chiyoda, Tokyo, 100-0004, Japan
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11
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Chaves G, Jardin C, Derst C, Musset B. Voltage-Gated Proton Channels in the Tree of Life. Biomolecules 2023; 13:1035. [PMID: 37509071 PMCID: PMC10377628 DOI: 10.3390/biom13071035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
With a single gene encoding HV1 channel, proton channel diversity is particularly low in mammals compared to other members of the superfamily of voltage-gated ion channels. Nonetheless, mammalian HV1 channels are expressed in many different tissues and cell types where they exert various functions. In the first part of this review, we regard novel aspects of the functional expression of HV1 channels in mammals by differentially comparing their involvement in (1) close conjunction with the NADPH oxidase complex responsible for the respiratory burst of phagocytes, and (2) in respiratory burst independent functions such as pH homeostasis or acid extrusion. In the second part, we dissect expression of HV channels within the eukaryotic tree of life, revealing the immense diversity of the channel in other phylae, such as mollusks or dinoflagellates, where several genes encoding HV channels can be found within a single species. In the last part, a comprehensive overview of the biophysical properties of a set of twenty different HV channels characterized electrophysiologically, from Mammalia to unicellular protists, is given.
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Affiliation(s)
- Gustavo Chaves
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christophe Jardin
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christian Derst
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Boris Musset
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
- Center of Physiology, Pathophysiology and Biophysics, The Salzburg Location, Paracelsus Medical University, 5020 Salzburg, Austria
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12
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Kostritskii AY, Machtens JP. Domain- and state-specific shape of the electric field tunes voltage sensing in voltage-gated sodium channels. Biophys J 2023; 122:1807-1821. [PMID: 37077046 PMCID: PMC10209041 DOI: 10.1016/j.bpj.2023.04.013] [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: 12/30/2022] [Revised: 03/27/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023] Open
Abstract
The ability to sense transmembrane voltage underlies most physiological roles of voltage-gated sodium (Nav) channels. Whereas the key role of their voltage-sensing domains (VSDs) in channel activation is well established, the molecular underpinnings of voltage coupling remain incompletely understood. Voltage-dependent energetics of the activation process can be described in terms of the gating charge that is defined by coupling of charged residues to the external electric field. The shape of the electric field within VSDs is therefore crucial for the activation of voltage-gated ion channels. Here, we employed molecular dynamics simulations of cardiac Nav1.5 and bacterial NavAb, together with our recently developed tool g_elpot, to gain insights into the voltage-sensing mechanisms of Nav channels via high-resolution quantification of VSD electrostatics. In contrast to earlier low-resolution studies, we found that the electric field within VSDs of Nav channels has a complex isoform- and domain-specific shape, which prominently depends on the activation state of a VSD. Different VSDs vary not only in the length of the region where the electric field is focused but also differ in their overall electrostatics, with possible implications in the diverse ion selectivity of their gating pores. Due to state-dependent field reshaping, not only translocated basic but also relatively immobile acidic residues contribute significantly to the gating charge. In the case of NavAb, we found that the transition between structurally resolved activated and resting states results in a gating charge of 8e, which is noticeably lower than experimental estimates. Based on the analysis of VSD electrostatics in the two activation states, we propose that the VSD likely adopts a deeper resting state upon hyperpolarization. In conclusion, our results provide an atomic-level description of the gating charge, demonstrate diversity in VSD electrostatics, and reveal the importance of electric-field reshaping for voltage sensing in Nav channels.
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Affiliation(s)
- Andrei Y Kostritskii
- Institute of Biological Information Processing (IBI-1), Molekular- und Zellphysiologie, and JARA-HPC, Forschungszentrum Jülich, Jülich, Germany; Institute of Clinical Pharmacology, RWTH Aachen University, Aachen, Germany.
| | - Jan-Philipp Machtens
- Institute of Biological Information Processing (IBI-1), Molekular- und Zellphysiologie, and JARA-HPC, Forschungszentrum Jülich, Jülich, Germany; Institute of Clinical Pharmacology, RWTH Aachen University, Aachen, Germany.
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13
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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14
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Choudhury K, Howard RJ, Delemotte L. An α-π transition in S6 shapes the conformational cycle of the bacterial sodium channel NavAb. J Gen Physiol 2022; 155:213748. [PMID: 36515966 PMCID: PMC9754703 DOI: 10.1085/jgp.202213214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/17/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels play an important role in electrical signaling in excitable cells. In response to changes in membrane potential, they cycle between nonconducting and conducting conformations. With recent advances in structural biology, structures of sodium channels have been captured in several distinct conformations, which are thought to represent different functional states. However, it has been difficult to capture the intrinsically transient open state. We recently showed that a proposed open state of the bacterial sodium channel NavMs was not conductive and that a conformational change involving a transition to a π-helix in the pore-lining S6 helix converted this structure into a conducting state. However, the relevance of this structural feature in other sodium channels, and its implications for the broader gating cycle, remained unclear. Here, we propose a comparable open state of another class of bacterial channel from Aliarcobacter butzleri (NavAb) with characteristic pore hydration, ion permeation, and drug binding properties. Furthermore, we show that a π-helix transition can lead to pore opening and that such a conformational change blocks fenestrations in the inner helix bundle. We also discover that a region in the C-terminal domain can undergo a disordering transition proposed to be important for pore opening. These results support a role for a π-helix transition in the opening of NavAb, enabling new proposals for the structural annotation and drug modulation mechanisms in this important sodium channel model.
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Affiliation(s)
- Koushik Choudhury
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Rebecca J. Howard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden,Correspondence to Lucie Delemotte:
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15
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Gamal El-Din TM. When the Gates Swing Open Only: Arrhythmia Mutations That Target the Fast Inactivation Gate of Na v1.5. Cells 2022; 11:cells11233714. [PMID: 36496974 PMCID: PMC9735811 DOI: 10.3390/cells11233714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/17/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Nav1.5 is the main voltage-gated sodium channel found in cardiac muscle, where it facilitates the fast influx of Na+ ions across the cell membrane, resulting in the fast depolarization phase-phase 0 of the cardiac action potential. As a result, it plays a major role in determining the amplitude and the upstroke velocity of the cardiac impulse. Quantitively, cardiac sodium channel activates in less than a millisecond to trigger the cardiac action potential and inactivates within 2-3 ms to facilitate repolarization and return to the resting state in preparation for firing the next action potential. Missense mutations in the gene that encodes Nav1.5 (SCN5A), change these time constants which leads to a wide spectrum of cardiac diseases ranging from long QT syndrome type 3 (LQT3) to sudden cardiac death. In this mini-review I will focus on the missense mutations in the inactivation gate of Nav1.5 that results in arrhythmia, attempting to correlate the location of the missense mutation to their specific phenotype.
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16
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Mechanism of voltage gating in the voltage-sensing phosphatase Ci-VSP. Proc Natl Acad Sci U S A 2022; 119:e2206649119. [PMID: 36279472 PMCID: PMC9636939 DOI: 10.1073/pnas.2206649119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Conformational changes in voltage-sensing domains (VSDs) are driven by the transmembrane electric field acting on the protein charges. Yet, the overall energetics and detailed mechanism of this process are not fully understood. Here, we determined free energy and displacement charge landscapes as well as the major conformations visited during a complete functional gating cycle in the isolated VSD of the phosphatase Ci-VSP (Ci-VSD) comprising four transmembrane helices (segments S1 to S4). Molecular dynamics simulations highlight the extent of S4 movements. In addition to the crystallographically determined activated “Up” and resting “Down” states, the simulations predict two Ci-VSD conformations: a deeper resting state (“down-minus”) and an extended activated (“up-plus”) state. These additional conformations were experimentally probed via systematic cysteine mutagenesis with metal-ion bridges and the engineering of proton conducting mutants at hyperpolarizing voltages. The present results show that these four states are visited sequentially in a stepwise manner during voltage activation, each step translocating one arginine or the equivalent of ∼1
e
0
across the membrane electric field, yielding a transfer of ∼3
e
0
charges in total for the complete process.
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17
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Jiang D, Zhang J, Xia Z. Structural Advances in Voltage-Gated Sodium Channels. Front Pharmacol 2022; 13:908867. [PMID: 35721169 PMCID: PMC9204039 DOI: 10.3389/fphar.2022.908867] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are responsible for the rapid rising-phase of action potentials in excitable cells. Over 1,000 mutations in NaV channels are associated with human diseases including epilepsy, periodic paralysis, arrhythmias and pain disorders. Natural toxins and clinically-used small-molecule drugs bind to NaV channels and modulate their functions. Recent advances from cryo-electron microscopy (cryo-EM) structures of NaV channels reveal invaluable insights into the architecture, activation, fast inactivation, electromechanical coupling, ligand modulation and pharmacology of eukaryotic NaV channels. These structural analyses not only demonstrate molecular mechanisms for NaV channel structure and function, but also provide atomic level templates for rational development of potential subtype-selective therapeutics. In this review, we summarize recent structural advances of eukaryotic NaV channels, highlighting the structural features of eukaryotic NaV channels as well as distinct modulation mechanisms by a wide range of modulators from natural toxins to synthetic small-molecules.
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Affiliation(s)
- Daohua Jiang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Daohua Jiang,
| | - Jiangtao Zhang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhanyi Xia
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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18
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Fouda MA, Ghovanloo MR, Ruben PC. Late sodium current: incomplete inactivation triggers seizures, myotonias, arrhythmias, and pain syndromes. J Physiol 2022; 600:2835-2851. [PMID: 35436004 DOI: 10.1113/jp282768] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
Acquired and inherited dysfunction in voltage-gated sodium channels underlies a wide range of diseases. "In addition to the defects in trafficking and expression, sodium channelopathies are also caused by dysfunction in one or several gating properties, for instance activation or inactivation. Disruption of the channel inactivation leads to the increased late sodium current, which is a common defect in seizure disorders, cardiac arrhythmias skeletal muscle myotonia and pain. An increase in late sodium current leads to repetitive action potential in neurons and skeletal muscles, and prolonged action potential duration in the heart. In this topical review, we compare the effects of late sodium current in brain, heart, skeletal muscle, and peripheral nerves. Abstract figure legend Shows cartoon illustration of general Nav channel transitions between (1) resting, (2) open, and (3) fast inactivated states. Disruption of the inactivation process exacerbates (4) late sodium currents. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mohamed A Fouda
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | | | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
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19
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Awuah DO, Hussain MS, Ponnapalli A, Deliwala SS, Seedahmed EM, Bachuwa G. Refractory familial hypokalaemic periodic paralysis leading to cardiovascular compromise. BMJ Case Rep 2022; 15:e246674. [PMID: 35131788 PMCID: PMC8823031 DOI: 10.1136/bcr-2021-246674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2021] [Indexed: 11/03/2022] Open
Abstract
Familial hypokalaemic periodic paralysis (FHPP) is a rare neuromuscular disorder that is classified under periodic paralysis (PP), which is characterised by episodes of muscle weakness. Common triggers include intense exercise, fasting or consumption of carbohydrate-rich meals. Hypokalaemic PP has an incidence of 1 in 100 000; despite the temporal association, cardiac manifestations are exceedingly rare. We present a case of FHPP, a channelopathy presenting with severe refractory hypokalaemia. The challenges with our patient were maintaining potassium levels within normal ranges and initiating a close follow-up plan. Due to the lack of clinical guidance in our case, many aspects of care, including surveillance, medications and genetic testing, remain unaddressed. Medical management includes aggressive correction with supplements, potassium-sparing diuretics and carbonic anhydrase inhibitors. Severe cases of dysrhythmias, especially ventricular fibrillation, require electrophysiology evaluation and possible implantation of a defibrillator to prevent sudden cardiac death.
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Affiliation(s)
- Dominic O Awuah
- Internal Medicine, Hurley Medical Center, Flint, Michigan, USA
| | | | | | | | | | - Ghassan Bachuwa
- Internal Medicine, Hurley Medical Center, Flint, Michigan, USA
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20
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Choudhury K, Kasimova MA, McComas S, Howard RJ, Delemotte L. An open state of a voltage-gated sodium channel involving a π-helix and conserved pore-facing asparagine. Biophys J 2022; 121:11-22. [PMID: 34890580 PMCID: PMC8758419 DOI: 10.1016/j.bpj.2021.12.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/26/2021] [Accepted: 12/06/2021] [Indexed: 01/07/2023] Open
Abstract
Voltage-gated sodium (Nav) channels play critical roles in propagating action potentials and otherwise manipulating ionic gradients in excitable cells. These channels open in response to membrane depolarization, selectively permeating sodium ions until rapidly inactivating. Structural characterization of the gating cycle in this channel family has proved challenging, particularly due to the transient nature of the open state. A structure from the bacterium Magnetococcus marinus Nav (NavMs) was initially proposed to be open, based on its pore diameter and voltage-sensor conformation. However, the functional annotation of this model, and the structural details of the open state, remain disputed. In this work, we used molecular modeling and simulations to test possible open-state models of NavMs. The full-length experimental structure, termed here the α-model, was consistently dehydrated at the activation gate, indicating an inability to conduct ions. Based on a spontaneous transition observed in extended simulations, and sequence/structure comparison to other Nav channels, we built an alternative π-model featuring a helix transition and the rotation of a conserved asparagine residue into the activation gate. Pore hydration, ion permeation, and state-dependent drug binding in this model were consistent with an open functional state. This work thus offers both a functional annotation of the full-length NavMs structure and a detailed model for a stable Nav open state, with potential conservation in diverse ion-channel families.
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Affiliation(s)
- Koushik Choudhury
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Marina A. Kasimova
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Sarah McComas
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Rebecca J. Howard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden,Corresponding author
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21
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Autism-associated mutations in K V7 channels induce gating pore current. Proc Natl Acad Sci U S A 2021; 118:2112666118. [PMID: 34728568 PMCID: PMC8609342 DOI: 10.1073/pnas.2112666118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 12/12/2022] Open
Abstract
Autism spectrum disorder (ASD) adversely impacts >1% of children in the United States, causing social interaction deficits, repetitive behaviors, and communication disorders. Genetic analysis of ASD has advanced dramatically through genome sequencing, which has identified >500 genes with mutations in ASD. Mutations that alter arginine gating charges in the voltage sensor of the voltage-gated potassium (KV) channel KV7 (KCNQ) are among those frequently associated with ASD. We hypothesized that these gating charge mutations would induce gating pore current (also termed ω-current) by causing an ionic leak through the mutant voltage sensor. Unexpectedly, we found that wild-type KV7 conducts outward gating pore current through its native voltage sensor at positive membrane potentials, owing to a glutamine in the third gating charge position. In bacterial and human KV7 channels, gating charge mutations at the R1 and R2 positions cause inward gating pore current through the resting voltage sensor at negative membrane potentials, whereas mutation at R4 causes outward gating pore current through the activated voltage sensor at positive potentials. Remarkably, expression of the KV7.3/R2C ASD-associated mutation in vivo in midbrain dopamine neurons of mice disrupts action potential generation and repetitive firing. Overall, our results reveal native and mutant gating pore current in KV7 channels and implicate altered control of action potential generation by gating pore current through mutant KV7 channels as a potential pathogenic mechanism in autism.
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22
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Ygberg S, Akkuratov EE, Howard RJ, Taylan F, Jans DC, Mahato DR, Katz A, Kinoshita PF, Portal B, Nennesmo I, Lindskog M, Karlish SJD, Andersson M, Lindstrand A, Brismar H, Aperia A. A missense mutation converts the Na +,K +-ATPase into an ion channel and causes therapy-resistant epilepsy. J Biol Chem 2021; 297:101355. [PMID: 34717959 PMCID: PMC8637647 DOI: 10.1016/j.jbc.2021.101355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 10/14/2021] [Accepted: 10/25/2021] [Indexed: 11/16/2022] Open
Abstract
The ion pump Na+,K+-ATPase is a critical determinant of neuronal excitability; however, its role in the etiology of diseases of the central nervous system (CNS) is largely unknown. We describe here the molecular phenotype of a Trp931Arg mutation of the Na+,K+-ATPase catalytic α1 subunit in an infant diagnosed with therapy-resistant lethal epilepsy. In addition to the pathological CNS phenotype, we also detected renal wasting of Mg2+. We found that membrane expression of the mutant α1 protein was low, and ion pumping activity was lost. Arginine insertion into membrane proteins can generate water-filled pores in the plasma membrane, and our molecular dynamic (MD) simulations of the principle states of Na+,K+-ATPase transport demonstrated massive water inflow into mutant α1 and destabilization of the ion-binding sites. MD simulations also indicated that a water pathway was created between the mutant arginine residue and the cytoplasm, and analysis of oocytes expressing mutant α1 detected a nonspecific cation current. Finally, neurons expressing mutant α1 were observed to be depolarized compared with neurons expressing wild-type protein, compatible with a lowered threshold for epileptic seizures. The results imply that Na+,K+-ATPase should be considered a neuronal locus minoris resistentia in diseases associated with epilepsy and with loss of plasma membrane integrity.
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Affiliation(s)
- Sofia Ygberg
- Neuropediatric Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
| | - Evgeny E Akkuratov
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Rebecca J Howard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Fulya Taylan
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Daniel C Jans
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | | | - Adriana Katz
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovoth, Israel
| | - Paula F Kinoshita
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Benjamin Portal
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Inger Nennesmo
- Department of Pathology, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Lindskog
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Steven J D Karlish
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovoth, Israel
| | | | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden; Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
| | - Anita Aperia
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
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23
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The gating pore blocker 1-(2,4-xylyl)guanidinium selectively inhibits pacemaking of midbrain dopaminergic neurons. Neuropharmacology 2021; 197:108722. [PMID: 34273387 DOI: 10.1016/j.neuropharm.2021.108722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/22/2022]
Abstract
Although several ionic mechanisms are known to control rate and regularity of the slow pacemaker in dopamine (DA) neurons, the core mechanism of pacing is controversial. Here we tested the hypothesis that pacemaking of SNc DA neurons is enabled by an unconventional conductance. We found that 1-(2,4-xylyl)guanidinium (XG), an established blocker of gating pore currents, selectively inhibits pacemaking of DA neurons. The compound inhibited all slow pacemaking DA neurons that were tested, both in the substantia nigra pars compacta, and in the ventral tegmental area. Interestingly, bursting behavior was not affected by XG. Furthermore, the drug did not affect fast pacemaking of GABAergic neurons from substantia nigra pars reticulata neurons or slow pacemaking of noradrenergic neurons. In DA neurons, current-clamp analysis revealed that XG did not appear to affect ion channels involved in the action potential. Its inhibitory effect persisted during blockade of all ion channels previously suggested to contribute to pacemaking. RNA sequencing and voltage-clamp recordings yielded no evidence for a gating pore current to underlie the conductance. However, we could isolate a small subthreshold XG-sensitive current, which was carried by both Na+ and Cl- ions. Although the molecular target of XG remains to be defined, these observations represent a step towards understanding pacemaking in DA neurons.
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24
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Qian K, Cao S, Liu X. Appeared inexplicable disorders of consciousness after general anesthesia tracheal tube drawing in endoscopic tympanoplasty. IBRAIN 2021; 7:113-118. [PMID: 37786906 PMCID: PMC10528784 DOI: 10.1002/j.2769-2795.2021.tb00073.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/14/2021] [Accepted: 05/24/2021] [Indexed: 10/04/2023]
Abstract
Background Disorders of consciousness (DOC) are neurocognitive disorders related to sharp fluctuations of attention and consciousness, while DOC is characterized by significant interindividual differences, rapid development, and a higher lethal rate. Case information A 53-year-old female patient underwent general anesthesia with tracheal intubation in otoendoscopic tympanoplasty. The patient suddenly appeared moderate DOC after tracheal tube removal with K+ 3.6 (3.5-5.3 mmol/L). Based on the ancillary testing and routine laboratory workup, the possible causes of DOC, such as general anesthesia drugs and cardio cerebral events, were temporarily excluded. DOC was reversed by intravenous administration of KCl 1 g, with K+ 3.78 mmol/L. On one day after surgery, the patient occurred suddenly DOC again after intravenous guttae of 5% glucose 1000 ml, K+ 3.87 mmol/L, possibly because of her recurrent hypokalemic paralysis (HP) of past medical history. The patient's consciousness gradually improved after effective KCl supplementation therapy. Conclusion DOC caused by periodic paralysis (PP) has not been reported, we speculate that hypoactive DOC is closely correlated with normokalemic periodic paralysis (NormoPP) in this case.
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Affiliation(s)
- Kun Qian
- Department of AnesthesiologyThe Affiliated Hospital of Zunyi Medical UniversityZunyiGuizhouChina
| | - Song Cao
- Department of PainThe Affiliated Hospital of Zunyi Medical UniversityZunyiGuizhouChina
| | - Xing‐Kui Liu
- College of Anesthesiology, Zunyi Medical UniversityZunyiGuizhouChina
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25
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Ghovanloo MR, Choudhury K, Bandaru TS, Fouda MA, Rayani K, Rusinova R, Phaterpekar T, Nelkenbrecher K, Watkins AR, Poburko D, Thewalt J, Andersen OS, Delemotte L, Goodchild SJ, Ruben PC. Cannabidiol inhibits the skeletal muscle Nav1.4 by blocking its pore and by altering membrane elasticity. J Gen Physiol 2021; 153:211970. [PMID: 33836525 PMCID: PMC8042605 DOI: 10.1085/jgp.202012701] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/13/2020] [Accepted: 03/16/2021] [Indexed: 12/12/2022] Open
Abstract
Cannabidiol (CBD) is the primary nonpsychotropic phytocannabinoid found in Cannabis sativa, which has been proposed to be therapeutic against many conditions, including muscle spasms. Among its putative targets are voltage-gated sodium channels (Navs), which have been implicated in many conditions. We investigated the effects of CBD on Nav1.4, the skeletal muscle Nav subtype. We explored direct effects, involving physical block of the Nav pore, as well as indirect effects, involving modulation of membrane elasticity that contributes to Nav inhibition. MD simulations revealed CBD's localization inside the membrane and effects on bilayer properties. Nuclear magnetic resonance (NMR) confirmed these results, showing CBD localizing below membrane headgroups. To determine the functional implications of these findings, we used a gramicidin-based fluorescence assay to show that CBD alters membrane elasticity or thickness, which could alter Nav function through bilayer-mediated regulation. Site-directed mutagenesis in the vicinity of the Nav1.4 pore revealed that removing the local anesthetic binding site with F1586A reduces the block of INa by CBD. Altering the fenestrations in the bilayer-spanning domain with Nav1.4-WWWW blocked CBD access from the membrane into the Nav1.4 pore (as judged by MD). The stabilization of inactivation, however, persisted in WWWW, which we ascribe to CBD-induced changes in membrane elasticity. To investigate the potential therapeutic value of CBD against Nav1.4 channelopathies, we used a pathogenic Nav1.4 variant, P1158S, which causes myotonia and periodic paralysis. CBD reduces excitability in both wild-type and the P1158S variant. Our in vitro and in silico results suggest that CBD may have therapeutic value against Nav1.4 hyperexcitability.
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Affiliation(s)
- Mohammad-Reza Ghovanloo
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.,Department of Cellular and Molecular Biology, Xenon Pharmaceuticals, Burnaby, BC, Canada.,Science for Life Laboratory, Department of Physics, Royal Institute of Technology, Solna, Sweden
| | - Koushik Choudhury
- Science for Life Laboratory, Department of Physics, Royal Institute of Technology, Solna, Sweden
| | - Tagore S Bandaru
- Science for Life Laboratory, Department of Physics, Royal Institute of Technology, Solna, Sweden
| | - Mohamed A Fouda
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.,Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | - Kaveh Rayani
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Radda Rusinova
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
| | - Tejas Phaterpekar
- Department of Molecular Biology and Biochemistry/Physics, Simon Fraser University, Burnaby, BC, Canada
| | - Karen Nelkenbrecher
- Department of Cellular and Molecular Biology, Xenon Pharmaceuticals, Burnaby, BC, Canada
| | - Abeline R Watkins
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Damon Poburko
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Jenifer Thewalt
- Department of Molecular Biology and Biochemistry/Physics, Simon Fraser University, Burnaby, BC, Canada
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Physics, Royal Institute of Technology, Solna, Sweden
| | - Samuel J Goodchild
- Department of Cellular and Molecular Biology, Xenon Pharmaceuticals, Burnaby, BC, Canada
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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26
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Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
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Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
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27
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Striessnig J. Voltage-Gated Ca 2+-Channel α1-Subunit de novo Missense Mutations: Gain or Loss of Function - Implications for Potential Therapies. Front Synaptic Neurosci 2021; 13:634760. [PMID: 33746731 PMCID: PMC7966529 DOI: 10.3389/fnsyn.2021.634760] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
This review summarizes our current knowledge of human disease-relevant genetic variants within the family of voltage gated Ca2+ channels. Ca2+ channelopathies cover a wide spectrum of diseases including epilepsies, autism spectrum disorders, intellectual disabilities, developmental delay, cerebellar ataxias and degeneration, severe cardiac arrhythmias, sudden cardiac death, eye disease and endocrine disorders such as congential hyperinsulinism and hyperaldosteronism. A special focus will be on the rapidly increasing number of de novo missense mutations identified in the pore-forming α1-subunits with next generation sequencing studies of well-defined patient cohorts. In contrast to likely gene disrupting mutations these can not only cause a channel loss-of-function but can also induce typical functional changes permitting enhanced channel activity and Ca2+ signaling. Such gain-of-function mutations could represent therapeutic targets for mutation-specific therapy of Ca2+-channelopathies with existing or novel Ca2+-channel inhibitors. Moreover, many pathogenic mutations affect positive charges in the voltage sensors with the potential to form gating-pore currents through voltage sensors. If confirmed in functional studies, specific blockers of gating-pore currents could also be of therapeutic interest.
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Affiliation(s)
- Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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28
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Alberini G, Benfenati F, Maragliano L. Structural Mechanism of ω-Currents in a Mutated Kv7.2 Voltage Sensor Domain from Molecular Dynamics Simulations. J Chem Inf Model 2021; 61:1354-1367. [PMID: 33570938 PMCID: PMC8023575 DOI: 10.1021/acs.jcim.0c01407] [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] [Indexed: 01/10/2023]
Abstract
![]()
Activation of voltage-gated
ion channels is regulated by conformational
changes of the voltage sensor domains (VSDs), four water- and ion-impermeable
modules peripheral to the central, permeable pore domain. Anomalous
currents, defined as ω-currents, have been recorded in response
to mutations of residues on the VSD S4 helix and associated with ion
fluxes through the VSDs. In humans, gene defects in the potassium
channel Kv7.2 result in a broad range of epileptic disorders, from
benign neonatal seizures to severe epileptic encephalopathies. Experimental
evidence suggests that the R207Q mutation in S4, associated with peripheral
nerve hyperexcitability, induces ω-currents at depolarized potentials,
but the fine structural details are still elusive. In this work, we
use atom-detailed molecular dynamics simulations and a refined model
structure of the Kv7.2 VSD in the active conformation in a membrane/water
environment to study the effect of R207Q and four additional mutations
of proven clinical importance. Our results demonstrate that the R207Q
mutant shows the most pronounced increase of hydration in the internal
VSD cavity, a feature favoring the occurrence of ω-currents.
Free energy and kinetics calculations of sodium permeation through
the native and mutated VSD indicate as more favorable the formation
of a cationic current in the latter. Overall, our simulations establish
a mechanistic linkage between genetic variations and their physiological
outcome, by providing a computational description that includes both
thermodynamic and kinetic features of ion permeation associated with
ω-currents.
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Affiliation(s)
- Giulio Alberini
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi, 10, 16132 Genova, Italy.,Department of Experimental Medicine, Università degli Studi di Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi, 10, 16132 Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi, 10, 16132 Genova, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi, 10, 16132 Genova, Italy.,Department of Life and Environmental Sciences, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
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29
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Solé L, Wagnon JL, Tamkun MM. Functional analysis of three Na v1.6 mutations causing early infantile epileptic encephalopathy. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165959. [PMID: 32916281 DOI: 10.1016/j.bbadis.2020.165959] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/21/2020] [Accepted: 09/03/2020] [Indexed: 11/24/2022]
Abstract
The voltage-gated sodium channel Nav1.6 is associated with more than 300 cases of epileptic encephalopathy. Nav1.6 epilepsy-causing mutations are spread over the entire channel's structure and only 10% of mutations have been characterized at the molecular level, with most of them being gain of function mutations. In this study, we analyzed three previously uncharacterized Nav1.6 epilepsy-causing mutations: G214D, N215D and V216D, located within a mutation hot-spot at the S3-S4 extracellular loop of Domain1. Voltage clamp experiments showed a 6-16 mV hyperpolarizing shift in the activation mid-point for all three mutants. V216D presented the largest shift along with decreased current amplitude, enhanced inactivation and a lack of persistent current. Recordings at hyperpolarized potentials indicated that all three mutants presented gating pore currents. Furthermore, trafficking experiments performed in cultured hippocampal neurons demonstrated that the mutants trafficked properly to the cell surface, with no significant differences regarding surface expression within the axon initial segment or soma compared to wild-type. These trafficking data suggest that the disease-causing consequences are due to only changes in the biophysical properties of the channel. Interestingly, the patient carrying the V216D mutation, which is the mutant with the greatest electrophysiological changes as compared to wild-type, exhibited the most severe phenotype. These results emphasize that these mutations will mandate unique treatment approaches, for normal sodium channel blockers may not work given that the studied mutations present gating pore currents. This study emphasizes the importance of molecular characterization of disease-causing mutations in order to improve the pharmacological treatment of patients.
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Affiliation(s)
- Laura Solé
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO 80523, USA; Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Jacy L Wagnon
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
| | - Michael M Tamkun
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO 80523, USA; Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA; Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
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30
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Ortner NJ, Kaserer T, Copeland JN, Striessnig J. De novo CACNA1D Ca 2+ channelopathies: clinical phenotypes and molecular mechanism. Pflugers Arch 2020; 472:755-773. [PMID: 32583268 PMCID: PMC7351864 DOI: 10.1007/s00424-020-02418-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/04/2020] [Accepted: 06/10/2020] [Indexed: 12/15/2022]
Abstract
The identification of rare disease-causing variants in humans by large-scale next-generation sequencing (NGS) studies has also provided us with new insights into the pathophysiological role of de novo missense variants in the CACNA1D gene that encodes the pore-forming α1-subunit of voltage-gated Cav1.3 L-type Ca2+ channels. These CACNA1D variants have been identified somatically in aldosterone-producing adenomas as well as germline in patients with neurodevelopmental and in some cases endocrine symptoms. In vitro studies in heterologous expression systems have revealed typical gating changes that indicate enhanced Ca2+ influx through Cav1.3 channels as the underlying disease-causing mechanism. Here we summarize the clinical findings of 12 well-characterized individuals with a total of 9 high-risk pathogenic CACNA1D variants. Moreover, we propose how information from somatic mutations in aldosterone-producing adenomas could be used to predict the potential pathogenicity of novel germline variants. Since these pathogenic de novo variants can cause a channel-gain-of function, we also discuss the use of L-type Ca2+ channel blockers as a potential therapeutic option.
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Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
| | - Teresa Kaserer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - J Nathan Copeland
- Duke Center for Autism and Brain Development, Duke Child and Family Mental Health and Developmental Neuroscience, Durham, USA
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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31
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Chu Y, Qiu P, Yu R. Centipede Venom Peptides Acting on Ion Channels. Toxins (Basel) 2020; 12:toxins12040230. [PMID: 32260499 PMCID: PMC7232367 DOI: 10.3390/toxins12040230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022] Open
Abstract
Centipedes are among the oldest venomous arthropods that use their venom to subdue the prey. The major components of centipede venom are a variety of low-molecular-weight peptide toxins that have evolved to target voltage-gated ion channels to interfere with the central system of prey and produce pain or paralysis for efficient hunting. Peptide toxins usually contain several intramolecular disulfide bonds, which confer chemical, thermal and biological stability. In addition, centipede peptides generally have novel structures and high potency and specificity and therefore hold great promise both as diagnostic tools and in the treatment of human disease. Here, we review the centipede peptide toxins with reported effects on ion channels, including Nav, Kv, Cav and the nonselective cation channel polymodal transient receptor potential vanilloid 1 (TRPV1).
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Affiliation(s)
- YanYan Chu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Marine Biomedical Research Institute of Qingdao, Qingdao 266071, China
- Correspondence: (Y.C.); (R.Y.)
| | - PeiJu Qiu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Marine Biomedical Research Institute of Qingdao, Qingdao 266071, China
| | - RiLei Yu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Correspondence: (Y.C.); (R.Y.)
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32
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Groome JR, Bayless-Edwards L. Roles for Countercharge in the Voltage Sensor Domain of Ion Channels. Front Pharmacol 2020; 11:160. [PMID: 32180723 PMCID: PMC7059764 DOI: 10.3389/fphar.2020.00160] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 02/07/2020] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated ion channels share a common structure typified by peripheral, voltage sensor domains. Their S4 segments respond to alteration in membrane potential with translocation coupled to ion permeation through a central pore domain. The mechanisms of gating in these channels have been intensely studied using pioneering methods such as measurement of charge displacement across a membrane, sequencing of genes coding for voltage-gated ion channels, and the development of all-atom molecular dynamics simulations using structural information from prokaryotic and eukaryotic channel proteins. One aspect of this work has been the description of the role of conserved negative countercharges in S1, S2, and S3 transmembrane segments to promote sequential salt-bridge formation with positively charged residues in S4 segments. These interactions facilitate S4 translocation through the lipid bilayer. In this review, we describe functional and computational work investigating the role of these countercharges in S4 translocation, voltage sensor domain hydration, and in diseases resulting from countercharge mutations.
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Affiliation(s)
- James R. Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID, United States
| | - Landon Bayless-Edwards
- Department of Biological Sciences, Idaho State University, Pocatello, ID, United States
- Oregon Health and Sciences University School of Medicine, Portland, OR, United States
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33
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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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34
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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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35
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Myotonia in a patient with a mutation in an S4 arginine residue associated with hypokalaemic periodic paralysis and a concomitant synonymous CLCN1 mutation. Sci Rep 2019; 9:17560. [PMID: 31772215 PMCID: PMC6879752 DOI: 10.1038/s41598-019-54041-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 11/05/2019] [Indexed: 12/14/2022] Open
Abstract
The sarcolemmal voltage gated sodium channel NaV1.4 conducts the key depolarizing current that drives the upstroke of the skeletal muscle action potential. It contains four voltage-sensing domains (VSDs) that regulate the opening of the pore domain and ensuing permeation of sodium ions. Mutations that lead to increased NaV1.4 currents are found in patients with myotonia or hyperkalaemic periodic paralysis (HyperPP). Myotonia is also caused by mutations in the CLCN1gene that result in loss-of-function of the skeletal muscle chloride channel ClC-1. Mutations affecting arginine residues in the fourth transmembrane helix (S4) of the NaV1.4 VSDs can result in a leak current through the VSD and hypokalemic periodic paralysis (HypoPP), but these have hitherto not been associated with myotonia. We report a patient with an Nav1.4 S4 arginine mutation, R222Q, presenting with severe myotonia without fulminant paralytic episodes. Other mutations affecting the same residue, R222W and R222G, have been found in patients with HypoPP. We show that R222Q channels have enhanced activation, consistent with myotonia, but also conduct a leak current. The patient carries a concomitant synonymous CLCN1 variant that likely worsens the myotonia and potentially contributes to the amelioration of muscle paralysis. Our data show phenotypic variability for different mutations affecting the same S4 arginine that have implications for clinical therapy.
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36
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Mason ER, Wu F, Patel RR, Xiao Y, Cannon SC, Cummins TR. Resurgent and Gating Pore Currents Induced by De Novo SCN2A Epilepsy Mutations. eNeuro 2019; 6:ENEURO.0141-19.2019. [PMID: 31558572 PMCID: PMC6795554 DOI: 10.1523/eneuro.0141-19.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/12/2019] [Accepted: 09/16/2019] [Indexed: 12/31/2022] Open
Abstract
Over 150 mutations in the SCN2A gene, which encodes the neuronal Nav1.2 protein, have been implicated in human epilepsy cases. Of these, R1882Q and R853Q are two of the most commonly reported mutations. This study utilized voltage-clamp electrophysiology to characterize the biophysical effects of the R1882Q and R853Q mutations on the hNav1.2 channel, including their effects on resurgent current and gating pore current, which are not typically investigated in the study of Nav1.2 channel mutations. HEK cells transiently transfected with DNA encoding either wild-type (WT) or mutant hNav1.2 revealed that the R1882Q mutation induced a gain-of-function phenotype, including slowed fast inactivation, depolarization of the voltage dependence of inactivation, and increased persistent current. In this model system, the R853Q mutation primarily produced loss-of-function effects, including reduced transient current amplitude and density, hyperpolarization of the voltage dependence of inactivation, and decreased persistent current. The presence of a Navβ4 peptide (KKLITFILKKTREK-OH) in the pipette solution induced resurgent currents, which were increased by the R1882Q mutation and decreased by the R853Q mutation. Further study of the R853Q mutation in Xenopus oocytes indicated a reduced surface expression and revealed a robust gating pore current at negative membrane potentials, a function absent in the WT channel. This not only shows that different epileptogenic point mutations in hNav1.2 have distinct biophysical effects on the channel, but also illustrates that individual mutations can have complex consequences that are difficult to identify using conventional analyses. Distinct mutations may, therefore, require tailored pharmacotherapies in order to eliminate seizures.
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Affiliation(s)
- Emily R Mason
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA 90095-1751
| | - Reesha R Patel
- Program in Medical Neuroscience, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Yucheng Xiao
- School of Science, Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA 90095-1751
| | - Theodore R Cummins
- School of Science, Biology Department Chair, Indiana University-Purdue University of Indianapolis, Indianapolis, IN 46202
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37
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Myshkin MY, Männikkö R, Krumkacheva OA, Kulbatskii DS, Chugunov AO, Berkut AA, Paramonov AS, Shulepko MA, Fedin MV, Hanna MG, Kullmann DM, Bagryanskaya EG, Arseniev AS, Kirpichnikov MP, Lyukmanova EN, Vassilevski AA, Shenkarev ZO. Cell-Free Expression of Sodium Channel Domains for Pharmacology Studies. Noncanonical Spider Toxin Binding Site in the Second Voltage-Sensing Domain of Human Na v1.4 Channel. Front Pharmacol 2019; 10:953. [PMID: 31555136 PMCID: PMC6737007 DOI: 10.3389/fphar.2019.00953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/26/2019] [Indexed: 01/06/2023] Open
Abstract
Voltage-gated sodium (NaV) channels are essential for the normal functioning of cardiovascular, muscular, and nervous systems. These channels have modular organization; the central pore domain allows current flow and provides ion selectivity, whereas four peripherally located voltage-sensing domains (VSDs-I/IV) are needed for voltage-dependent gating. Mutations in the S4 voltage-sensing segments of VSDs in the skeletal muscle channel NaV1.4 trigger leak (gating pore) currents and cause hypokalemic and normokalemic periodic paralyses. Previously, we have shown that the gating modifier toxin Hm-3 from the crab spider Heriaeus melloteei binds to the S3-S4 extracellular loop in VSD-I of NaV1.4 channel and inhibits gating pore currents through the channel with mutations in VSD-I. Here, we report that Hm-3 also inhibits gating pore currents through the same channel with the R675G mutation in VSD-II. To investigate the molecular basis of Hm-3 interaction with VSD-II, we produced the corresponding 554-696 fragment of NaV1.4 in a continuous exchange cell-free expression system based on the Escherichia coli S30 extract. We then performed a combined nuclear magnetic resonance (NMR) and electron paramagnetic resonance spectroscopy study of isolated VSD-II in zwitterionic dodecylphosphocholine/lauryldimethylamine-N-oxide or dodecylphosphocholine micelles. To speed up the assignment of backbone resonances, five selectively 13C,15N-labeled VSD-II samples were produced in accordance with specially calculated combinatorial scheme. This labeling approach provides assignment for ∼50% of the backbone. Obtained NMR and electron paramagnetic resonance data revealed correct secondary structure, quasi-native VSD-II fold, and enhanced ps-ns timescale dynamics in the micelle-solubilized domain. We modeled the structure of the VSD-II/Hm-3 complex by protein-protein docking involving binding surfaces mapped by NMR. Hm-3 binds to VSDs I and II using different modes. In VSD-II, the protruding ß-hairpin of Hm-3 interacts with the S1-S2 extracellular loop, and the complex is stabilized by ionic interactions between the positively charged toxin residue K24 and the negatively charged channel residues E604 or D607. We suggest that Hm-3 binding to these charged groups inhibits voltage sensor transition to the activated state and blocks the depolarization-activated gating pore currents. Our results indicate that spider toxins represent a useful hit for periodic paralyses therapy development and may have multiple structurally different binding sites within one NaV molecule.
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Affiliation(s)
- Mikhail Yu Myshkin
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Roope Männikkö
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | | | - Dmitrii S Kulbatskii
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Anton O Chugunov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia.,International Laboratory for Supercomputer Atomistic Modelling and Multi-scale Analysis, National Research University Higher School of Economics, Moscow, Russia
| | - Antonina A Berkut
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexander S Paramonov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail A Shulepko
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, Novosibirsk, Russia
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom
| | - Elena G Bagryanskaya
- N.N.Voroztsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk, Russia
| | - Alexander S Arseniev
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Ekaterina N Lyukmanova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | - Alexander A Vassilevski
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | - Zakhar O Shenkarev
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
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38
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Pinggera A, Negro G, Tuluc P, Brown MJ, Lieb A, Striessnig J. Gating defects of disease-causing de novo mutations in Ca v1.3 Ca 2+ channels. Channels (Austin) 2019; 12:388-402. [PMID: 30465465 PMCID: PMC6287693 DOI: 10.1080/19336950.2018.1546518] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Recently, we and others identified somatic and germline de novo gain-of-function mutations in CACNA1D, the gene encoding the α1-subunit of voltage-gated Cav1.3 Ca2+-channels. While somatic mutations identified in aldosterone producing adenomas (APAs) underlie treatment-resistant hypertension, germline CACNA1D mutations are associated with a neurodevelopmental disorder characterized by a wide symptomatic spectrum, including autism spectrum disorder. The number of newly identified CACNA1D missense mutations is constantly growing, but their pathogenic potential is difficult to predict in silico, making functional studies indispensable to assess their contribution to disease risk. Here we report the functional characterization of previously identified CACNA1D APA mutations F747L and M1354I using whole-cell patch-clamp electrophysiology upon recombinant expression in tsA-201 cells. We also investigated if alternative splicing of Cav1.3 affects the aberrant gating of the previously characterized APA mutation R990H and two mutations associated with autism spectrum disorder (A479G and G407R). Splice-variant dependent gating changes are of particular interest for germline mutations, since the relative expression of Cav1.3 splice variants differs across different tissues and within brain regions and might therefore result in tissue-specific phenotypes. Our data revealed a complex gain-of-function phenotype for APA mutation F747L confirming its pathogenic role. Furthermore, we found splice-variant dependent gating changes in R990H, A749G and G407R. M1354I did not change channel function of Cav1.3 splice variants and should therefore be considered a rare non-pathogenic variant until further proof for its pathogenicity is obtained. Our new findings together with previously published data allow classification of pathogenic CACNA1D mutations into four categories based on prototypical functional changes.
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Affiliation(s)
- Alexandra Pinggera
- a Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences , University of Innsbruck , Innsbruck , Austria
| | - Giulia Negro
- a Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences , University of Innsbruck , Innsbruck , Austria
| | - Petronel Tuluc
- a Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences , University of Innsbruck , Innsbruck , Austria
| | - Morris J Brown
- b William Harvey Research Institute , Queen Mary University of London , London , UK
| | - Andreas Lieb
- a Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences , University of Innsbruck , Innsbruck , Austria
| | - Jörg Striessnig
- a Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences , University of Innsbruck , Innsbruck , Austria
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39
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Wang AH, Zhang ZC, Li GH. Advances in enhanced sampling molecular dynamics simulations for biomolecules. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1905091] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- An-hui Wang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Zhi-chao Zhang
- State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Guo-hui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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40
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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41
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Corradi V, Sejdiu BI, Mesa-Galloso H, Abdizadeh H, Noskov SY, Marrink SJ, Tieleman DP. Emerging Diversity in Lipid-Protein Interactions. Chem Rev 2019; 119:5775-5848. [PMID: 30758191 PMCID: PMC6509647 DOI: 10.1021/acs.chemrev.8b00451] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Membrane
lipids interact with proteins in a variety of ways, ranging
from providing a stable membrane environment for proteins to being
embedded in to detailed roles in complicated and well-regulated protein
functions. Experimental and computational advances are converging
in a rapidly expanding research area of lipid–protein interactions.
Experimentally, the database of high-resolution membrane protein structures
is growing, as are capabilities to identify the complex lipid composition
of different membranes, to probe the challenging time and length scales
of lipid–protein interactions, and to link lipid–protein
interactions to protein function in a variety of proteins. Computationally,
more accurate membrane models and more powerful computers now enable
a detailed look at lipid–protein interactions and increasing
overlap with experimental observations for validation and joint interpretation
of simulation and experiment. Here we review papers that use computational
approaches to study detailed lipid–protein interactions, together
with brief experimental and physiological contexts, aiming at comprehensive
coverage of simulation papers in the last five years. Overall, a complex
picture of lipid–protein interactions emerges, through a range
of mechanisms including modulation of the physical properties of the
lipid environment, detailed chemical interactions between lipids and
proteins, and key functional roles of very specific lipids binding
to well-defined binding sites on proteins. Computationally, despite
important limitations, molecular dynamics simulations with current
computer power and theoretical models are now in an excellent position
to answer detailed questions about lipid–protein interactions.
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Affiliation(s)
- Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Besian I Sejdiu
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haydee Mesa-Galloso
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
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42
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Brown BM, Nguyen HM, Wulff H. Recent advances in our understanding of the structure and function of more unusual cation channels. F1000Res 2019; 8. [PMID: 30755796 PMCID: PMC6354322 DOI: 10.12688/f1000research.17163.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/23/2019] [Indexed: 12/18/2022] Open
Abstract
As their name implies, cation channels allow the regulated flow of cations such as sodium, potassium, calcium, and magnesium across cellular and intracellular membranes. Cation channels have long been known for their fundamental roles in controlling membrane potential and excitability in neurons and muscle. In this review, we provide an update on the recent advances in our understanding of the structure–function relationship and the physiological and pathophysiological role of cation channels. The most exciting developments in the last two years, in our opinion, have been the insights that cryoelectron microscopy has provided into the inner life and the gating of not only voltage-gated channels but also mechanosensitive and calcium- or sodium-activated channels. The mechanosensitive Piezo channels especially have delighted the field not only with a fascinating new type of structure but with important roles in blood pressure regulation and lung function.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Hai M Nguyen
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
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43
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Kokunai Y, Dalle C, Vicart S, Sternberg D, Pouliot V, Bendahhou S, Fournier E, Chahine M, Fontaine B, Nicole S. A204E mutation in Na v1.4 DIS3 exerts gain- and loss-of-function effects that lead to periodic paralysis combining hyper- with hypo-kalaemic signs. Sci Rep 2018; 8:16681. [PMID: 30420713 PMCID: PMC6232142 DOI: 10.1038/s41598-018-34750-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/25/2018] [Indexed: 12/11/2022] Open
Abstract
Periodic paralyses (PP) are characterized by episodic muscle weakness and are classified into the distinct hyperkalaemic (hyperPP) and hypokalaemic (hypoPP) forms. The dominantly-inherited form of hyperPP is caused by overactivity of Nav1.4 - the skeletal muscle voltage-gated sodium channel. Familial hypoPP results from a leaking gating pore current induced by dominant mutations in Nav1.4 or Cav1.1, the skeletal muscle voltage-gated calcium channel. Here, we report an individual with clinical signs of hyperPP and hypokalaemic episodes of muscle paralysis who was heterozygous for the novel p.Ala204Glu (A204E) substitution located in one region of Nav1.4 poor in disease-related variations. A204E induced a significant decrease of sodium current density, increased the window current, enhanced fast and slow inactivation of Nav1.4, and did not cause gating pore current in functional analyses. Interestingly, the negative impact of A204E on Nav1.4 activation was strengthened in low concentration of extracellular K+. Our data prove the existence of a phenotype combining signs of hyperPP and hypoPP due to dominant Nav1.4 mutations. The hyperPP component would result from gain-of-function effects on Nav1.4 and the hypokalemic episodes of paralysis from loss-of-function effects strengthened by low K+. Our data argue for a non-negligible role of Nav1.4 loss-of-function in familial hypoPP.
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Affiliation(s)
- Yosuke Kokunai
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Carine Dalle
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Savine Vicart
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Damien Sternberg
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Valérie Pouliot
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Said Bendahhou
- CNRS UMR7370, LP2M, Labex ICST, University Nice Sophia-Antipolis, Faculté de Médecine, Nice, France
| | - Emmanuel Fournier
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Mohamed Chahine
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Bertrand Fontaine
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France.
| | - Sophie Nicole
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
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44
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Zhang J, Tang D, Liu S, Hu H, Liang S, Tang C, Liu Z. Purification and Characterization of JZTx-14, a Potent Antagonist of Mammalian and Prokaryotic Voltage-Gated Sodium Channels. Toxins (Basel) 2018; 10:toxins10100408. [PMID: 30308978 PMCID: PMC6215091 DOI: 10.3390/toxins10100408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/04/2018] [Accepted: 10/06/2018] [Indexed: 12/19/2022] Open
Abstract
Exploring the interaction of ligands with voltage-gated sodium channels (NaVs) has advanced our understanding of their pharmacology. Herein, we report the purification and characterization of a novel non-selective mammalian and bacterial NaVs toxin, JZTx-14, from the venom of the spider Chilobrachys jingzhao. This toxin potently inhibited the peak currents of mammalian NaV1.2–1.8 channels and the bacterial NaChBac channel with low IC50 values (<1 µM), and it mainly inhibited the fast inactivation of the NaV1.9 channel. Analysis of NaV1.5/NaV1.9 chimeric channel showed that the NaV1.5 domain II S3–4 loop is involved in toxin association. Kinetics data obtained from studying toxin–NaV1.2 channel interaction showed that JZTx-14 was a gating modifier that possibly trapped the channel in resting state; however, it differed from site 4 toxin HNTx-III by irreversibly blocking NaV currents and showing state-independent binding with the channel. JZTx-14 might stably bind to a conserved toxin pocket deep within the NaV1.2–1.8 domain II voltage sensor regardless of channel conformation change, and its effect on NaVs requires the toxin to trap the S3–4 loop in its resting state. For the NaChBac channel, JZTx-14 positively shifted its conductance-voltage (G–V) and steady-state inactivation relationships. An alanine scan analysis of the NaChBac S3–4 loop revealed that the 108th phenylalanine (F108) was the key residue determining the JZTx-14–NaChBac interaction. In summary, this study provided JZTx-14 with potent but promiscuous inhibitory activity on both the ancestor bacterial NaVs and the highly evolved descendant mammalian NaVs, and it is a useful probe to understand the pharmacology of NaVs.
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Affiliation(s)
- Jie Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Shuangyu Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Haoliang Hu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
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45
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Moreau A, Chahine M. A New Cardiac Channelopathy: From Clinical Phenotypes to Molecular Mechanisms Associated With Na v1.5 Gating Pores. Front Cardiovasc Med 2018; 5:139. [PMID: 30356750 PMCID: PMC6189448 DOI: 10.3389/fcvm.2018.00139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
Voltage gated sodium channels (NaV) are broadly expressed in the human body. They are responsible for the initiation of action potentials in excitable cells. They also underlie several physiological processes such as cognitive, sensitive, motor, and cardiac functions. The NaV1.5 channel is the main NaV expressed in the heart. A dysfunction of this channel is usually associated with the development of pure electrical disorders such as long QT syndrome, Brugada syndrome, sinus node dysfunction, atrial fibrillation, and cardiac conduction disorders. However, mutations of Nav1.5 have recently been linked to the development of an atypical clinical entity combining complex arrhythmias and dilated cardiomyopathy. Although several Nav1.5 mutations have been linked to dilated cardiomyopathy phenotypes, their pathogenic mechanisms remain to be elucidated. The gating pore may constitute a common biophysical defect for all NaV1.5 mutations located in the channel's VSDs. The creation of such a gating pore may disrupt the ionic homeostasis of cardiomyocytes, affecting electrical signals, cell morphology, and cardiac myocyte function. The main objective of this article is to review the concept of gating pores and their role in structural heart diseases and to discuss potential pharmacological treatments.
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Affiliation(s)
- Adrien Moreau
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Mohamed Chahine
- CERVO Research Centre, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, Canada.,Department of Medicine, Université Laval, Quebec City, QC, Canada
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