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Nguyen PT, Harris BJ, Mateos DL, González AH, Murray AM, Yarov-Yarovoy V. Structural modeling of ion channels using AlphaFold2, RoseTTAFold2, and ESMFold. Channels (Austin) 2024; 18:2325032. [PMID: 38445990 PMCID: PMC10936637 DOI: 10.1080/19336950.2024.2325032] [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: 09/05/2023] [Accepted: 01/14/2024] [Indexed: 03/07/2024] Open
Abstract
Ion channels play key roles in human physiology and are important targets in drug discovery. The atomic-scale structures of ion channels provide invaluable insights into a fundamental understanding of the molecular mechanisms of channel gating and modulation. Recent breakthroughs in deep learning-based computational methods, such as AlphaFold, RoseTTAFold, and ESMFold have transformed research in protein structure prediction and design. We review the application of AlphaFold, RoseTTAFold, and ESMFold to structural modeling of ion channels using representative voltage-gated ion channels, including human voltage-gated sodium (NaV) channel - NaV1.8, human voltage-gated calcium (CaV) channel - CaV1.1, and human voltage-gated potassium (KV) channel - KV1.3. We compared AlphaFold, RoseTTAFold, and ESMFold structural models of NaV1.8, CaV1.1, and KV1.3 with corresponding cryo-EM structures to assess details of their similarities and differences. Our findings shed light on the strengths and limitations of the current state-of-the-art deep learning-based computational methods for modeling ion channel structures, offering valuable insights to guide their future applications for ion channel research.
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Affiliation(s)
- Phuong Tran Nguyen
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA
| | - Brandon John Harris
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA
- Biophysics Graduate Group, University of California School of Medicine, Davis, CA, USA
| | - Diego Lopez Mateos
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA
- Biophysics Graduate Group, University of California School of Medicine, Davis, CA, USA
| | - Adriana Hernández González
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA
- Biophysics Graduate Group, University of California School of Medicine, Davis, CA, USA
| | | | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA
- Department of Anesthesiology and Pain Medicine, University of California School of Medicine, Davis, CA, USA
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2
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Li Z, Wu Q, Yan N. A structural atlas of druggable sites on Na v channels. Channels (Austin) 2024; 18:2287832. [PMID: 38033122 PMCID: PMC10732651 DOI: 10.1080/19336950.2023.2287832] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023] Open
Abstract
Voltage-gated sodium (Nav) channels govern membrane excitability by initiating and propagating action potentials. Consistent with their physiological significance, dysfunction, or mutations in these channels are associated with various channelopathies. Nav channels are thereby major targets for various clinical and investigational drugs. In addition, a large number of natural toxins, both small molecules and peptides, can bind to Nav channels and modulate their functions. Technological breakthrough in cryo-electron microscopy (cryo-EM) has enabled the determination of high-resolution structures of eukaryotic and eventually human Nav channels, alone or in complex with auxiliary subunits, toxins, and drugs. These studies have not only advanced our comprehension of channel architecture and working mechanisms but also afforded unprecedented clarity to the molecular basis for the binding and mechanism of action (MOA) of prototypical drugs and toxins. In this review, we will provide an overview of the recent advances in structural pharmacology of Nav channels, encompassing the structural map for ligand binding on Nav channels. These findings have established a vital groundwork for future drug development.
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Affiliation(s)
- Zhangqiang Li
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiurong Wu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong Province, China
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3
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Collaço RDC, Van Petegem F, Bosmans F. ω-Grammotoxin-SIA inhibits voltage-gated Na+ channel currents. J Gen Physiol 2024; 156:e202413563. [PMID: 39042091 PMCID: PMC11270453 DOI: 10.1085/jgp.202413563] [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: 02/09/2024] [Revised: 06/14/2024] [Accepted: 07/10/2024] [Indexed: 07/24/2024] Open
Abstract
ω-Grammotoxin-SIA (GrTX-SIA) was originally isolated from the venom of the Chilean rose tarantula and demonstrated to function as a gating modifier of voltage-gated Ca2+ (CaV) channels. Later experiments revealed that GrTX-SIA could also inhibit voltage-gated K+ (KV) channel currents via a similar mechanism of action that involved binding to a conserved S3-S4 region in the voltage-sensing domains (VSDs). Since voltage-gated Na+ (NaV) channels contain homologous structural motifs, we hypothesized that GrTX-SIA could inhibit members of this ion channel family as well. Here, we show that GrTX-SIA can indeed impede the gating process of multiple NaV channel subtypes with NaV1.6 being the most susceptible target. Moreover, molecular docking of GrTX-SIA onto NaV1.6, supported by a p.E1607K mutation, revealed the voltage sensor in domain IV (VSDIV) as being a primary site of action. The biphasic manner in which current inhibition appeared to occur suggested a second, possibly lower-sensitivity binding locus, which was identified as VSDII by using KV2.1/NaV1.6 chimeric voltage-sensor constructs. Subsequently, the NaV1.6p.E782K/p.E838K (VSDII), NaV1.6p.E1607K (VSDIV), and particularly the combined VSDII/VSDIV mutant lost virtually all susceptibility to GrTX-SIA. Together with existing literature, our data suggest that GrTX-SIA recognizes modules in NaV channel VSDs that are conserved among ion channel families, thereby allowing it to act as a comprehensive ion channel gating modifier peptide.
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Affiliation(s)
- Rita de Cássia Collaço
- Department of Basic and Applied Medical Sciences, Molecular Physiology and Neurophysics Group, Ghent University, Ghent, Belgium
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
- Life Sciences Institute, University of British Columbia , Vancouver, Canada
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Molecular Physiology and Neurophysics Group, Ghent University, Ghent, Belgium
- Faculty of Medicine and Pharmacy, Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels, Belgium
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4
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Akbari Ahangar A, Elhanafy E, Blanton H, Li J. Mapping structural distribution and gating-property impacts of disease-associated mutations in voltage-gated sodium channels. iScience 2024; 27:110678. [PMID: 39286500 PMCID: PMC11404175 DOI: 10.1016/j.isci.2024.110678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 06/18/2024] [Accepted: 08/02/2024] [Indexed: 09/19/2024] Open
Abstract
Thousands of voltage-gated sodium (Nav) channel variants contribute to a variety of disorders, including epilepsy, cardiac arrhythmia, and pain disorders. Yet, the effects of more variants remain unclear. The conventional gain-of-function (GoF) or loss-of-function (LoF) classifications are frequently employed to interpret mutations' effects and guide therapy for sodium channelopathies. Our study challenges this binary classification by analyzing 525 mutations associated with 34 diseases across 366 electrophysiology studies, revealing that diseases with similar GoF/LoF effects can stem from unique molecular mechanisms. Utilizing UniProt data, we mapped over 2,400 disease-associated missense mutations across Nav channels. This analysis pinpoints key mutation hotspots and maps patterns of gating-property impacts for the mutations, respectively, located around the selectivity filter, activation gate, fast inactivation region, and voltage-sensing domains. This study shows great potential to enhance prediction accuracy for mutational effects based on the structural context, paving the way for targeted drug design in precision medicine.
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Affiliation(s)
- Amin Akbari Ahangar
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA
| | - Eslam Elhanafy
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA
| | - Hayden Blanton
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA
| | - Jing Li
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA
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5
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Elhanafy E, Akbari Ahangar A, Roth R, Gamal El-Din TM, Bankston JR, Li J. Elucidating the Differential Impacts of Equivalent Gating-Charge Mutations in Voltage-Gated Sodium Channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.09.612021. [PMID: 39314455 PMCID: PMC11419121 DOI: 10.1101/2024.09.09.612021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Voltage-gated sodium (Na v ) channels are pivotal for cellular signaling and mutations in Na v channels can lead to excitability disorders in cardiac, muscular, and neural tissues. A major cluster of pathological mutations localizes in the voltage-sensing domains (VSDs), resulting in either gain-of-function (GoF), loss-of-function (LoF) effects, or both. However, the mechanism behind this functional divergence of mutations at equivalent positions remains elusive. Through hotspot analysis, we identified three gating charges (R1, R2, and R3) as major mutational hotspots in VSDs. The same amino-acid substitutions at equivalent gating-charge positions in VSD I and VSD II of the cardiac sodium channel Na v 1.5 show differential gating-property impacts in electrophysiology measurements. We conducted 120 µs molecular dynamics (MD) simulations on wild-type and six mutants to elucidate the structural basis of their differential impacts. Our μs-scale MD simulations with applied external electric fields captured VSD state transitions and revealed the differential structural dynamics between equivalent R-to-Q mutants. Notably, we observed transient leaky conformations in some mutants during structural transitions, offering a detailed structural explanation for gating-pore currents. Our salt-bridge network analysis uncovered VSD-specific and state-dependent interactions among gating charges, countercharges, and lipids. This detailed analysis elucidated how mutations disrupt critical electrostatic interactions, thereby altering VSD permeability and modulating gating properties. By demonstrating the crucial importance of considering the specific structural context of each mutation, our study represents a significant leap forward in understanding structure- function relationships in Na v channels. Our work establishes a robust framework for future investigations into the molecular basis of ion channel-related disorders.
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Tikhonova TB, Sharkov AA, Zhorov BS, Vassilevski AA. Diverse biophysical mechanisms in voltage-gated sodium channel Na v1.4 variants associated with myotonia. FASEB J 2024; 38:e23883. [PMID: 39150825 DOI: 10.1096/fj.202400867r] [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: 04/16/2024] [Revised: 07/14/2024] [Accepted: 07/31/2024] [Indexed: 08/18/2024]
Abstract
Mutations in SCN4A gene encoding Nav1.4 channel α-subunit, are known to cause neuromuscular disorders such as myotonia or paralysis. Here, we study the effect of two amino acid replacements, K1302Q and G1306E, in the DIII-IV loop of the channel, corresponding to mutations found in patients with myotonia. We combine clinical, electrophysiological, and molecular modeling data to provide a holistic picture of the molecular mechanisms operating in mutant channels and eventually leading to pathology. We analyze the existing clinical data for patients with the K1302Q substitution, which was reported for adults with or without myotonia phenotypes, and report two new unrelated patients with the G1306E substitution, who presented with severe neonatal episodic laryngospasm and childhood-onset myotonia. We provide a functional analysis of the mutant channels by expressing Nav1.4 α-subunit in Xenopus oocytes in combination with β1 subunit and recording sodium currents using two-electrode voltage clamp. The K1302Q variant exhibits abnormal voltage dependence of steady-state fast inactivation, being the likely cause of pathology. K1302Q does not lead to decelerated fast inactivation, unlike several other myotonic mutations such as G1306E. For both mutants, we observe increased window currents corresponding to a larger population of channels available for activation. To elaborate the structural rationale for our experimental data, we explore the contacts involving K/Q1302 and E1306 in the AlphaFold2 model of wild-type Nav1.4 and Monte Carlo-minimized models of mutant channels. Our data provide the missing evidence to support the classification of K1302Q variant as likely pathogenic and may be used by clinicians.
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Affiliation(s)
- Tatiana B Tikhonova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Artem A Sharkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Veltischev Research and Clinical Institute for Pediatrics and Pediatric Surgery of the Pirogov Russian National Research Medical University, Moscow, Russia
- Genomed Ltd., Moscow, Russia
| | - Boris S Zhorov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Moscow Institute of Physics and Technology, State University, Dolgoprudny, Russia
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7
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Neumann B, McCarthy S, Gonen S. Structural basis of inhibition of human Na V1.8 by the tarantula venom peptide Protoxin-I. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609828. [PMID: 39253517 PMCID: PMC11383277 DOI: 10.1101/2024.08.27.609828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Voltage-gated sodium channels (NaVs) selectively permit diffusion of sodium ions across the cell membrane and, in excitable cells, are responsible for propagating action potentials. One of the nine human NaV isoforms, NaV1.8, is a promising target for analgesics, and selective inhibitors are of interest as therapeutics. One such inhibitor, the gating-modifier peptide Protoxin-I derived from tarantula venom, blocks channel opening by shifting the activation voltage threshold to more depolarised potentials, but the structural basis for this inhibition has not previously been determined. Using monolayer graphene grids, we report the cryogenic electron microscopy structures of full-length human apo-NaV1.8 and the Protoxin-I-bound complex at 3.1 Å and 2.8 Å resolution, respectively. The apo structure shows an unexpected movement of the Domain I S4-S5 helix, and VSDI was unresolvable. We find that Protoxin-I binds to and displaces the VSDII S3-S4 linker, hindering translocation of the S4II helix during activation.
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Affiliation(s)
- Bryan Neumann
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
| | - Stephen McCarthy
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
| | - Shane Gonen
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
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8
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Palmisano VF, Anguita-Ortiz N, Faraji S, Nogueira JJ. Voltage-Gated Ion Channels: Structure, Pharmacology and Photopharmacology. Chemphyschem 2024; 25:e202400162. [PMID: 38649320 DOI: 10.1002/cphc.202400162] [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: 02/23/2024] [Revised: 04/21/2024] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
Voltage-gated ion channels are transmembrane proteins responsible for the generation and propagation of action potentials in excitable cells. Over the last decade, advancements have enabled the elucidation of crystal structures of ion channels. This progress in structural understanding, particularly in identifying the binding sites of local anesthetics, opens avenues for the design of novel compounds capable of modulating ion conduction. However, many traditional drugs lack selectivity and come with adverse side effects. The emergence of photopharmacology has provided an orthogonal way of controlling the activity of compounds, enabling the regulation of ion conduction with light. In this review, we explore the central pore region of voltage-gated sodium and potassium channels, providing insights from both structural and pharmacological perspectives. We discuss the different binding modes of synthetic compounds that can physically occlude the pore and, therefore, block ion conduction. Moreover, we examine recent advances in the photopharmacology of voltage-gated ion channels, introducing molecular approaches aimed at controlling their activity by using photosensitive drugs.
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Affiliation(s)
- Vito F Palmisano
- Department of Chemistry, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Theoretical Chemistry Group, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Nuria Anguita-Ortiz
- Department of Chemistry, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Shirin Faraji
- Theoretical Chemistry Group, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Juan J Nogueira
- Department of Chemistry, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- IADCHEM, Institute for Advanced Research in Chemistry, Universidad Autónoma de Madrid, 28049, Madrid, Spain
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9
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Phulera S, Dickson CJ, Schwalen CJ, Khoshouei M, Cassell SJ, Sun Y, Condos T, Whicher J, Weihofen WA. Scorpion α-toxin LqhαIT specifically interacts with a glycan at the pore domain of voltage-gated sodium channels. Structure 2024:S0969-2126(24)00284-3. [PMID: 39181123 DOI: 10.1016/j.str.2024.07.021] [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: 02/12/2024] [Revised: 06/13/2024] [Accepted: 07/30/2024] [Indexed: 08/27/2024]
Abstract
Voltage-gated sodium (Nav) channels sense membrane potential and drive cellular electrical activity. The deathstalker scorpion α-toxin LqhαIT exerts a strong action potential prolonging effect on Nav channels. To elucidate the mechanism of action of LqhαIT, we determined a 3.9 Å cryoelectron microscopy (cryo-EM) structure of LqhαIT in complex with the Nav channel from Periplaneta americana (NavPas). We found that LqhαIT binds to voltage sensor domain 4 and traps it in an "S4 down" conformation. The functionally essential C-terminal epitope of LqhαIT forms an extensive interface with the glycan scaffold linked to Asn330 of NavPas that augments a small protein-protein interface between NavPas and LqhαIT. A combination of molecular dynamics simulations, structural comparisons, and prior mutagenesis experiments demonstrates the functional importance of this toxin-glycan interaction. These findings establish a structural basis for the specificity achieved by scorpion α-toxins and reveal the conserved glycan as an essential component of the toxin-binding epitope.
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Affiliation(s)
- Swastik Phulera
- Discovery Sciences, Novartis Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Callum J Dickson
- Global Discovery Chemistry, Novartis Biomedical Research, 181 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Christopher J Schwalen
- Global Discovery Chemistry, Novartis Biomedical Research, 181 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Maryam Khoshouei
- Discovery Sciences, Novartis Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Samantha J Cassell
- Discovery Sciences, Novartis Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Yishan Sun
- Neuroscience, Novartis Biomedical Research, 22 Windsor St, Cambridge, MA 02139, USA
| | - Tara Condos
- Discovery Sciences, Novartis Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jonathan Whicher
- Discovery Sciences, Novartis Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Wilhelm A Weihofen
- Discovery Sciences, Novartis Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, USA.
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10
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Catterall WA, Gamal El-Din TM, Wisedchaisri G. The chemistry of electrical signaling in sodium channels from bacteria and beyond. Cell Chem Biol 2024; 31:1405-1421. [PMID: 39151407 DOI: 10.1016/j.chembiol.2024.07.010] [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: 01/12/2024] [Revised: 06/27/2024] [Accepted: 07/22/2024] [Indexed: 08/19/2024]
Abstract
Electrical signaling is essential for all fast processes in biology, but its molecular mechanisms have been uncertain. This review article focuses on studies of bacterial sodium channels in order to home in on the essential molecular and chemical mechanisms underlying transmembrane ion conductance and voltage-dependent gating without the overlay of complex protein interactions and regulatory mechanisms in mammalian sodium channels. This minimalist approach has yielded a nearly complete picture of sodium channel function at the atomic level that are mostly conserved in mammalian sodium channels, including sodium selectivity and conductance, voltage sensing and activation, electromechanical coupling to pore opening and closing, slow inactivation, and pathogenic dysfunction in a debilitating channelopathy. Future studies of nature's simplest sodium channels may continue to yield key insights into the fundamental molecular and chemical principles of their function and further elucidate the chemical basis of electrical signaling.
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Affiliation(s)
- 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.
| | - Goragot Wisedchaisri
- Department of Pharmacology, University of Washington, Seattle WA 98195-7280, USA.
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11
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Jin X, Huang J, Wang H, Wang K, Yan N. A versatile residue numbering scheme for Na v and Ca v channels. Cell Chem Biol 2024; 31:1394-1404. [PMID: 39151406 DOI: 10.1016/j.chembiol.2024.07.008] [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: 02/18/2024] [Revised: 07/01/2024] [Accepted: 07/18/2024] [Indexed: 08/19/2024]
Abstract
Voltage-gated sodium (Nav) and calcium (Cav) channels are responsible for the initiation of electrical signals. They have long been targeted for the treatment of various diseases. The mounting number of cryoelectron microscopy (cryo-EM) structures for diverse subtypes of Nav and Cav channels from multiple organisms necessitates a generic residue numbering system to establish the structure-function relationship and to aid rational drug design or optimization. Here we suggest a structure-based residue numbering scheme, centering around the most conserved residues on each of the functional segments. We elaborate the generic numbers through illustrative examples, focusing on representative drug-binding sites of eukaryotic Nav and Cav channels. We also extend the numbering scheme to compare common disease mutations among different Nav subtypes. Application of the generic residue numbering scheme affords immediate insights into hotspots for pathogenic mutations and critical loci for drug binding and will facilitate drug discovery targeting Nav and Cav channels.
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Affiliation(s)
- Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Huan Wang
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kan Wang
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Institute of Bio-Architecture and Bio-Interactions (IBABI), Shenzhen Medical Academy of Research and Translation, Guangming District, Shenzhen, Guangdong Province 518107, China; Shenzhen Bay Laboratory, Guangming District, Shenzhen, Guangdong Province 518132, China.
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12
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Pei S, Wang N, Mei Z, Zhangsun D, Craik DJ, McIntosh JM, Zhu X, Luo S. Conotoxins Targeting Voltage-Gated Sodium Ion Channels. Pharmacol Rev 2024; 76:828-845. [PMID: 38914468 PMCID: PMC11331937 DOI: 10.1124/pharmrev.123.000923] [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: 09/27/2023] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024] Open
Abstract
Voltage-gated sodium (NaV) channels are intimately involved in the generation and transmission of action potentials, and dysfunction of these channels may contribute to nervous system diseases, such as epilepsy, neuropathic pain, psychosis, autism, and cardiac arrhythmia. Many venom peptides selectively act on NaV channels. These include conotoxins, which are neurotoxins secreted by cone snails for prey capture or self-defense but which are also valuable pharmacological tools for the identification and/or treatment of human diseases. Typically, conotoxins contain two or three disulfide bonds, and these internal crossbraces contribute to conotoxins having compact, well defined structures and high stability. Of the conotoxins containing three disulfide bonds, some selectively target mammalian NaV channels and can block, stimulate, or modulate these channels. Such conotoxins have great potential to serve as pharmacological tools for studying the functions and characteristics of NaV channels or as drug leads for neurologic diseases related to NaV channels. Accordingly, discovering or designing conotoxins targeting NaV channels with high potency and selectivity is important. The amino acid sequences, disulfide bond connectivity, and three-dimensional structures are key factors that affect the biological activity of conotoxins, and targeted synthetic modifications of conotoxins can greatly improve their activity and selectivity. This review examines NaV channel-targeted conotoxins, focusing on their structures, activities, and designed modifications, with a view toward expanding their applications. SIGNIFICANCE STATEMENT: NaV channels are crucial in various neurologic diseases. Some conotoxins selectively target NaV channels, causing either blockade or activation, thus enabling their use as pharmacological tools for studying the channels' characteristics and functions. Conotoxins also have promising potential to be developed as drug leads. The disulfide bonds in these peptides are important for stabilizing their structures, thus leading to enhanced specificity and potency. Together, conotoxins targeting NaV channels have both immediate research value and promising future application prospects.
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Affiliation(s)
- Shengrong Pei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Nan Wang
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Zaoli Mei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Dongting Zhangsun
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - David J Craik
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - J Michael McIntosh
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Xiaopeng Zhu
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Sulan Luo
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
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13
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Huang J, Pan X, Yan N. Structural biology and molecular pharmacology of voltage-gated ion channels. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00763-7. [PMID: 39103479 DOI: 10.1038/s41580-024-00763-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2024] [Indexed: 08/07/2024]
Abstract
Voltage-gated ion channels (VGICs), including those for Na+, Ca2+ and K+, selectively permeate ions across the cell membrane in response to changes in membrane potential, thus participating in physiological processes involving electrical signalling, such as neurotransmission, muscle contraction and hormone secretion. Aberrant function or dysregulation of VGICs is associated with a diversity of neurological, psychiatric, cardiovascular and muscular disorders, and approximately 10% of FDA-approved drugs directly target VGICs. Understanding the structure-function relationship of VGICs is crucial for our comprehension of their working mechanisms and role in diseases. In this Review, we discuss how advances in single-particle cryo-electron microscopy have afforded unprecedented structural insights into VGICs, especially on their interactions with clinical and investigational drugs. We present a comprehensive overview of the recent advances in the structural biology of VGICs, with a focus on how prototypical drugs and toxins modulate VGIC activities. We explore how these structures elucidate the molecular basis for drug actions, reveal novel pharmacological sites, and provide critical clues to future drug discovery.
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Affiliation(s)
- Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Xiaojing Pan
- Institute of Bio-Architecture and Bio-Interactions (IBABI), Shenzhen Medical Academy of Research and Translation (SMART), Shenzhen, Guangdong, China.
| | - Nieng Yan
- Institute of Bio-Architecture and Bio-Interactions (IBABI), Shenzhen Medical Academy of Research and Translation (SMART), Shenzhen, Guangdong, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, China.
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14
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Goodchild SJ, Ahern CA. Conformational photo-trapping in Na V1.5: Inferring local motions at the "inactivation gate". Biophys J 2024; 123:2167-2175. [PMID: 38664963 PMCID: PMC11309974 DOI: 10.1016/j.bpj.2024.04.017] [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: 12/22/2023] [Revised: 03/22/2024] [Accepted: 04/18/2024] [Indexed: 05/12/2024] Open
Abstract
Rapid and effectual inactivation in voltage-gated sodium channels is required for canonical action-potential firing. This "fast" inactivation arises from swift and reversible protein conformational changes that utilize transmembrane segments and the cytoplasmic linker between channel domains III and IV. Until recently, fast inactivation had been accepted to rely on a "ball-and-chain" mechanism whereby a hydrophobic triplet of DIII-IV amino acids (IFM) impairs conductance by binding to a site in central pore of the channel made available by channel opening. New structures of sodium channels have upended this model. Specifically, cryo-electron microscopic structures of eukaryotic sodium channels depict a peripheral binding site for the IFM motif, outside of the pore, opening the possibility of a yet unidentified allosteric mechanism of fast-inactivation gating. We set out to study fast inactivation by photo-trapping human sodium channels in various functional states under voltage control. This was achieved by genetically encoding the crosslinking unnatural amino acid benzophenone phenylalanine at various sites within the DIII-IV linker in the cardiac sodium channel NaV1.5. These data show dynamic state- and positional-dependent trapping of the transient conformations associated with fast inactivation, each yielding different phenotypes and rates of trapping. These data reveal distinct conformational changes that underlie fast inactivation and point to a dynamic environment around the IFM locus.
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Affiliation(s)
- Samuel J Goodchild
- Department of Anesthesiology, Pharmacology and Therapeutics, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa.
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15
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Aman TK, Raman IM. Resurgent current in context: Insights from the structure and function of Na and K channels. Biophys J 2024; 123:1924-1941. [PMID: 38130058 PMCID: PMC11309984 DOI: 10.1016/j.bpj.2023.12.016] [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: 10/14/2023] [Revised: 12/07/2023] [Accepted: 12/18/2023] [Indexed: 12/23/2023] Open
Abstract
Discovered just over 25 years ago in cerebellar Purkinje neurons, resurgent Na current was originally described operationally as a component of voltage-gated Na current that flows upon repolarization from relatively depolarized potentials and speeds recovery from inactivation, increasing excitability. Its presence in many excitable cells and absence from others has raised questions regarding its biophysical and molecular mechanisms. Early studies proposed that Na channels capable of generating resurgent current are subject to a rapid open-channel block by an endogenous blocking protein, which binds upon depolarization and unblocks upon repolarization. Since the time that this mechanism was suggested, many physiological and structural studies of both Na and K channels have revealed aspects of gating and conformational states that provide insights into resurgent current. These include descriptions of domain movements for activation and inactivation, solution of cryo-EM structures with pore-blocking compounds, and identification of native blocking domains, proteins, and modulatory subunits. Such results not only allow the open-channel block hypothesis to be refined but also link it more clearly to research that preceded it. This review considers possible mechanisms for resurgent Na current in the context of earlier and later studies of ion channels and suggests a framework for future research.
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Affiliation(s)
- Teresa K Aman
- Department of Neurobiology, Northwestern University, Evanston, Illinois
| | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, Illinois.
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16
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Chow CY, King GF. Shining a Light on Venom-Peptide Receptors: Venom Peptides as Targeted Agents for In Vivo Molecular Imaging. Toxins (Basel) 2024; 16:307. [PMID: 39057947 PMCID: PMC11281729 DOI: 10.3390/toxins16070307] [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: 05/13/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
Molecular imaging has revolutionised the field of biomedical research by providing a non-invasive means to visualise and understand biochemical processes within living organisms. Optical fluorescent imaging in particular allows researchers to gain valuable insights into the dynamic behaviour of a target of interest in real time. Ion channels play a fundamental role in cellular signalling, and they are implicated in diverse pathological conditions, making them an attractive target in the field of molecular imaging. Many venom peptides exhibit exquisite selectivity and potency towards ion channels, rendering them ideal agents for molecular imaging applications. In this review, we illustrate the use of fluorescently-labelled venom peptides for disease diagnostics and intraoperative imaging of brain tumours and peripheral nerves. Finally, we address challenges for the development and clinical translation of venom peptides as nerve-targeted imaging agents.
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Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
- Australia Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
- Australia Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St. Lucia, QLD 4072, Australia
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17
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Moreira-Junior L, Leal-Cardoso JH, Cassola AC, Carvalho-de-Souza JL. Eugenol and lidocaine inhibit voltage-gated Na + channels from dorsal root ganglion neurons with different mechanisms. Front Pharmacol 2024; 15:1354737. [PMID: 38989141 PMCID: PMC11234063 DOI: 10.3389/fphar.2024.1354737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/08/2024] [Indexed: 07/12/2024] Open
Abstract
Eugenol (EUG) is a bioactive monoterpenoid used as an analgesic, preservative, and flavoring agent. Our new data show EUG as a voltage-gated Na+ channel (VGSC) inhibitor, comparable but not identical to lidocaine (LID). EUG inhibits both total and only TTX-R voltage-activated Na+ currents (INa) recorded from VGSCs naturally expressed on dorsal root ganglion sensory neurons in rats. Inhibition is quick, fully reversible, and dose-dependent. Our biophysical and pharmacological analyses showed that EUG and LID inhibit VGSCs with different mechanisms. EUG inhibits VGSCs with a dose-response relationship characterized by a Hill coefficient of 2, while this parameter for the inhibition by LID is 1. Furthermore, in a different way from LID, EUG modified the voltage dependence of both the VGSC activation and inactivation processes and the recovery from fast inactivated states and the entry to slow inactivated states. In addition, we suggest that EUG, but not LID, interacts with VGSC pre-open-closed states, according to our data.
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Affiliation(s)
- Luiz Moreira-Junior
- Department of Anesthesiology, University of Arizona, Tucson, AZ, United States
| | | | - Antonio Carlos Cassola
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, São Paulo, Brazil
| | - Joao Luis Carvalho-de-Souza
- Department of Anesthesiology, University of Arizona, Tucson, AZ, United States
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, São Paulo, Brazil
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18
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Xiao X, Mei Y, Deng W, Zou G, Hou H, Ji X. Electric Eel Biomimetics for Energy Storage and Conversion. SMALL METHODS 2024; 8:e2201435. [PMID: 36840652 DOI: 10.1002/smtd.202201435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The electric eel is known as the most powerful creature to generate electricity with a discharge voltage up to 860 V and peak current up to 1 A. These surprising properties are the results of billions of years of evolution on the electrical biological structure and bulk, and now have triggered great research interest in electric eel biomimetics for designing innovated configurations and components of energy storage and conversion devices. In this review, first, the bioelectrical behavior of electric eels is surveyed, followed by the physiological structure to reveal the discharge characteristics and principles of electric organs and electrocytes. Additionally, underlying electrochemical mechanisms and models for calculating the potential and current of electrocytes are presented. Central to this review is the recent progress of electric-eel-inspired innovations and applications for energy storage and conversion, particularly including novel power sources, triboelectric nanogenerators, and nanochannel ion-selective membranes for salinity gradient energy harvesting. Finally, insights on the challenges at the moment and the perspectives on the future research prospects are critically compiled. It is suggested that energy-related electric eel biomimetics will greatly boost the development of next-generation high performance, green, and functional electronics.
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Affiliation(s)
- Xiangting Xiao
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Yu Mei
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Wentao Deng
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Guoqiang Zou
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Hongshuai Hou
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Xiaobo Ji
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
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19
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Schott K, Usher SG, Serra O, Carnevale V, Pless SA, Chua HC. Unplugging lateral fenestrations of NALCN reveals a hidden drug binding site within the pore region. Proc Natl Acad Sci U S A 2024; 121:e2401591121. [PMID: 38787877 PMCID: PMC11145269 DOI: 10.1073/pnas.2401591121] [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: 01/23/2024] [Accepted: 04/09/2024] [Indexed: 05/26/2024] Open
Abstract
The sodium (Na+) leak channel (NALCN) is a member of the four-domain voltage-gated cation channel family that includes the prototypical voltage-gated sodium and calcium channels (NaVs and CaVs, respectively). Unlike NaVs and CaVs, which have four lateral fenestrations that serve as routes for lipophilic compounds to enter the central cavity to modulate channel function, NALCN has bulky residues (W311, L588, M1145, and Y1436) that block these openings. Structural data suggest that occluded fenestrations underlie the pharmacological resistance of NALCN, but functional evidence is lacking. To test this hypothesis, we unplugged the fenestrations of NALCN by substituting the four aforementioned residues with alanine (AAAA) and compared the effects of NaV, CaV, and NALCN blockers on both wild-type (WT) and AAAA channels. Most compounds behaved in a similar manner on both channels, but phenytoin and 2-aminoethoxydiphenyl borate (2-APB) elicited additional, distinct responses on AAAA channels. Further experiments using single alanine mutants revealed that phenytoin and 2-APB enter the inner cavity through distinct fenestrations, implying structural specificity to their modes of access. Using a combination of computational and functional approaches, we identified amino acid residues critical for 2-APB activity, supporting the existence of drug binding site(s) within the pore region. Intrigued by the activity of 2-APB and its analogues, we tested compounds containing the diphenylmethane/amine moiety on WT channels. We identified clinically used drugs that exhibited diverse activity, thus expanding the pharmacological toolbox for NALCN. While the low potencies of active compounds reiterate the pharmacological resistance of NALCN, our findings lay the foundation for rational drug design to develop NALCN modulators with refined properties.
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Affiliation(s)
- Katharina Schott
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Samuel George Usher
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Oscar Serra
- Department of Biology, Temple University, Philadelphia, PA19122
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA19122
- Institute of Computational Molecular Science, Temple University, Philadelphia, PA19122
| | - Vincenzo Carnevale
- Department of Biology, Temple University, Philadelphia, PA19122
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA19122
- Institute of Computational Molecular Science, Temple University, Philadelphia, PA19122
| | - Stephan Alexander Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Han Chow Chua
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
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20
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Huffer K, Tan XF, Fernández-Mariño AI, Dhingra S, Swartz KJ. Dilation of ion selectivity filters in cation channels. Trends Biochem Sci 2024; 49:417-430. [PMID: 38514273 PMCID: PMC11069442 DOI: 10.1016/j.tibs.2024.02.004] [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: 12/12/2023] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 03/23/2024]
Abstract
Ion channels establish the voltage gradient across cellular membranes by providing aqueous pathways for ions to selectively diffuse down their concentration gradients. The selectivity of any given channel for its favored ions has conventionally been viewed as a stable property, and in many cation channels, it is determined by an ion-selectivity filter within the external end of the ion-permeation pathway. In several instances, including voltage-activated K+ (Kv) channels, ATP-activated P2X receptor channels, and transient receptor potential (TRP) channels, the ion-permeation pathways have been proposed to dilate in response to persistent activation, dynamically altering ion permeation. Here, we discuss evidence for dynamic ion selectivity, examples where ion selectivity filters exhibit structural plasticity, and opportunities to fill gaps in our current understanding.
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Affiliation(s)
- Kate Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiao-Feng Tan
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ana I Fernández-Mariño
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Surbhi Dhingra
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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21
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Bodawatta KH, Hu H, Schalk F, Daniel JM, Maiah G, Koane B, Iova B, Beemelmanns C, Poulsen M, Jønsson KA. Multiple mutations in the Nav1.4 sodium channel of New Guinean toxic birds provide autoresistance to deadly batrachotoxin. Mol Ecol 2024; 33:e16878. [PMID: 36779590 DOI: 10.1111/mec.16878] [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: 02/21/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 02/14/2023]
Abstract
Toxicity has evolved multiple times across the tree of life and serves important functions related to hunting, defence and parasite deterrence. Toxins are produced either in situ by the toxic organism itself or associated symbionts, or acquired through diet. The ability to exploit toxins from external sources requires adaptations that prevent toxic effects on the consumer (autoresistance). Here, we examine genomic adaptations that could facilitate autoresistance to the diet-acquired potent neurotoxic alkaloid batrachotoxin (BTX) in New Guinean toxic birds. Our work documents two new toxic bird species and shows that toxic birds carry multiple mutations in the SCN4A gene that are under positive selection. This gene encodes the most common vertebrate muscle Nav channel (Nav1.4). Molecular docking results indicate that some of the mutations that are present in the pore-forming segment of the Nav channel, where BTX binds, could reduce its binding affinity. These mutations should therefore prevent the continuous opening of the sodium channels that BTX binding elicits, thereby preventing muscle paralysis and ultimately death. Although these mutations are different from those present in Neotropical Phyllobates poison dart frogs, they occur in the same segments of the Nav1.4 channel. Consequently, in addition to uncovering a greater diversity of toxic bird species than previously known, our work provides an intriguing example of molecular-level convergent adaptations allowing frogs and birds to ingest and use the same neurotoxin. This suggests that genetically modified Nav1.4 channels represent a key adaptation to BTX tolerance and exploitation across vertebrates.
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Affiliation(s)
- Kasun H Bodawatta
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Haofu Hu
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Felix Schalk
- Chemical Biology of Microbe-Host Interactions, Leibniz Institute for Natural Product Research and Infection Biology e. V., Hans-Knöll-Institute, Jena, Germany
| | - Jan-Martin Daniel
- Chemical Biology of Microbe-Host Interactions, Leibniz Institute for Natural Product Research and Infection Biology e. V., Hans-Knöll-Institute, Jena, Germany
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
| | - Gibson Maiah
- The New Guinea Binatang Research Centre, Madang, Papua New Guinea
| | - Bonny Koane
- The New Guinea Binatang Research Centre, Madang, Papua New Guinea
| | - Bulisa Iova
- PNG National Museum and Art Gallery, Port Moresby, Papua New Guinea
| | - Christine Beemelmanns
- Chemical Biology of Microbe-Host Interactions, Leibniz Institute for Natural Product Research and Infection Biology e. V., Hans-Knöll-Institute, Jena, Germany
- Department Anti-infectives from Microbiota, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
- Universität des Saarlandes, Saarbrücken, Germany
| | - Michael Poulsen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Knud A Jønsson
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
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22
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Zou X, Zhang Z, Lu H, Zhao W, Pan L, Chen Y. Functional effects of drugs and toxins interacting with Na V1.4. Front Pharmacol 2024; 15:1378315. [PMID: 38725668 PMCID: PMC11079311 DOI: 10.3389/fphar.2024.1378315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/08/2024] [Indexed: 05/12/2024] Open
Abstract
NaV1.4 is a voltage-gated sodium channel subtype that is predominantly expressed in skeletal muscle cells. It is essential for producing action potentials and stimulating muscle contraction, and mutations in NaV1.4 can cause various muscle disorders. The discovery of the cryo-EM structure of NaV1.4 in complex with β1 has opened new possibilities for designing drugs and toxins that target NaV1.4. In this review, we summarize the current understanding of channelopathies, the binding sites and functions of chemicals including medicine and toxins that interact with NaV1.4. These substances could be considered novel candidate compounds or tools to develop more potent and selective drugs targeting NaV1.4. Therefore, studying NaV1.4 pharmacology is both theoretically and practically meaningful.
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Affiliation(s)
- Xinyi Zou
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Zixuan Zhang
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Hui Lu
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Wei Zhao
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Lanying Pan
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, China
| | - Yuan Chen
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
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23
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Biswas R, López-Serrano A, Huang HL, Ramirez-Navarro A, Grandinetti G, Heissler S, Deschênes I, Chinthalapudi K. Structural basis of human Na v1.5 gating mechanisms. RESEARCH SQUARE 2024:rs.3.rs-3985999. [PMID: 38659812 PMCID: PMC11042394 DOI: 10.21203/rs.3.rs-3985999/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Voltage-gated Nav1.5 channels are central to the generation and propagation of cardiac action potentials1. Aberrations in their function are associated with a wide spectrum of cardiac diseases including arrhythmias and heart failure2-5. Despite decades of progress in Nav1.5 biology6-8, the lack of structural insights into intracellular regions has hampered our understanding of its gating mechanisms. Here we present three cryo-EM structures of human Nav1.5 in previously unanticipated open states, revealing sequential conformational changes in gating charges of the voltage-sensing domains (VSDs) and several intracellular regions. Despite the channel being in the open state, these structures show the IFM motif repositioned in the receptor site but not dislodged. In particular, our structural findings highlight a dynamic C-terminal domain (CTD) and III-IV linker interaction, which regulates the conformation of VSDs and pore opening. Electrophysiological studies confirm that disrupting this interaction results in the fast inactivation of Nav1.5. Together, our structure-function studies establish a foundation for understanding the gating mechanisms of Nav1.5 and the mechanisms underlying CTD-related channelopathies.
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24
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Kalienkova V, Dandamudi M, Paulino C, Lynagh T. Structural basis for excitatory neuropeptide signaling. Nat Struct Mol Biol 2024; 31:717-726. [PMID: 38337033 PMCID: PMC11026163 DOI: 10.1038/s41594-023-01198-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 12/05/2023] [Indexed: 02/12/2024]
Abstract
Rapid signaling between neurons is mediated by ligand-gated ion channels, cell-surface proteins with an extracellular ligand-binding domain and a membrane-spanning ion channel domain. The degenerin/epithelial sodium channel (DEG/ENaC) superfamily is diverse in terms of its gating stimuli, with some DEG/ENaCs gated by neuropeptides, and others gated by pH, mechanical force or enzymatic activity. The mechanism by which ligands bind to and activate DEG/ENaCs is poorly understood. Here we dissected the structural basis for neuropeptide-gated activity of a neuropeptide-gated DEG/ENaC, FMRFamide-gated sodium channel 1 (FaNaC1) from the annelid worm Malacoceros fuliginosus, using cryo-electron microscopy. Structures of FaNaC1 in the ligand-free resting state and in several ligand-bound states reveal the ligand-binding site and capture the ligand-induced conformational changes of channel gating, which we verified with complementary mutagenesis experiments. Our results illuminate channel gating in DEG/ENaCs and offer a structural template for experimental dissection of channel pharmacology and ion conduction.
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Affiliation(s)
- Valeria Kalienkova
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Cristina Paulino
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
- Biochemistry Center, Heidelberg University, Heidelberg, Germany.
| | - Timothy Lynagh
- Michael Sars Centre, University of Bergen, Bergen, Norway.
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25
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Zhang L, Tian J, Lin Z, Dong Z. Efficient Sodium Transmembrane Permeation through Helically Folded Nanopores with Natural Channel-Like Ion Selectivity. J Am Chem Soc 2024; 146:8500-8507. [PMID: 38483183 DOI: 10.1021/jacs.3c14736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The selective transmembrane permeation of sodium ions achieved by biomimetic chemistry shows great potential to solve the problem of sodium ion transport blockade in diseases, but its implementation faces enormous difficulties. Herein, we design and synthesize a series of helically folded nanopores by employing a quinoline-oxadiazole structural sequence to finely replicate the pentahydrate structure of sodium ions. Surprisingly, these nanopores are capable of achieving sodium transmembrane permeation with ion selectivity at the level of natural sodium channels, as observed in rationally designed nanopores (M1-M5) with Na+/K+ ion selectivity ratio of up to 20.4. Moreover, slight structural variations in nanopore structures can switch ion transport modes between the channel and carrier. We found that, compared to the carrier mode, the channel mode not only transports ions faster but also has higher ion selectivity during transmembrane conduction, clearly illustrating that the trade-off phenomenon between ion selectivity and transport activity does not occur between the two transport modes of channel and carrier. At the same time, we also found that the spatial position and numbers of coordination sites are crucial for the sodium ion selectivity of the nanopores. Moreover, carrier M1 reported in this work is totally superior to the commercial Na+ carrier ETH2120, especially in terms of Na+/K+ ion selectivity, thus being a potentially practical Na+ carrier. Our study provides a new paradigm on the rational design of sodium-specific synthetic nanopores, which will open up the possibility for the application of artificial sodium-specific transmembrane permeation in biomedicine and disease treatment.
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Affiliation(s)
- Lei Zhang
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Jun Tian
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Ze Lin
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Zeyuan Dong
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
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26
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Goodchild SJ, Shuart NG, Williams AD, Ye W, Parrish RR, Soriano M, Thouta S, Mezeyova J, Waldbrook M, Dean R, Focken T, Ghovanloo MR, Ruben PC, Scott F, Cohen CJ, Empfield J, Johnson JP. Molecular Pharmacology of Selective Na V1.6 and Dual Na V1.6/Na V1.2 Channel Inhibitors that Suppress Excitatory Neuronal Activity Ex Vivo. ACS Chem Neurosci 2024; 15:1169-1184. [PMID: 38359277 PMCID: PMC10958515 DOI: 10.1021/acschemneuro.3c00757] [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: 11/21/2023] [Revised: 01/25/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Voltage-gated sodium channel (NaV) inhibitors are used to treat neurological disorders of hyperexcitability such as epilepsy. These drugs act by attenuating neuronal action potential firing to reduce excitability in the brain. However, all currently available NaV-targeting antiseizure medications nonselectively inhibit the brain channels NaV1.1, NaV1.2, and NaV1.6, which potentially limits the efficacy and therapeutic safety margins of these drugs. Here, we report on XPC-7724 and XPC-5462, which represent a new class of small molecule NaV-targeting compounds. These compounds specifically target inhibition of the NaV1.6 and NaV1.2 channels, which are abundantly expressed in excitatory pyramidal neurons. They have a > 100-fold molecular selectivity against NaV1.1 channels, which are predominantly expressed in inhibitory neurons. Sparing NaV1.1 preserves the inhibitory activity in the brain. These compounds bind to and stabilize the inactivated state of the channels thereby reducing the activity of excitatory neurons. They have higher potency, with longer residency times and slower off-rates, than the clinically used antiseizure medications carbamazepine and phenytoin. The neuronal selectivity of these compounds is demonstrated in brain slices by inhibition of firing in cortical excitatory pyramidal neurons, without impacting fast spiking inhibitory interneurons. XPC-5462 also suppresses epileptiform activity in an ex vivo brain slice seizure model, whereas XPC-7224 does not, suggesting a possible requirement of Nav1.2 inhibition in 0-Mg2+- or 4-AP-induced brain slice seizure models. The profiles of these compounds will facilitate pharmacological dissection of the physiological roles of NaV1.2 and NaV1.6 in neurons and help define the role of specific channels in disease states. This unique selectivity profile provides a new approach to potentially treat disorders of neuronal hyperexcitability by selectively downregulating excitatory circuits.
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Affiliation(s)
- Samuel J. Goodchild
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Noah Gregory Shuart
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Aaron D. Williams
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Wenlei Ye
- Neurocrine
Biosciences, San Diego, California 92130, United States
| | - R. Ryley Parrish
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Maegan Soriano
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Samrat Thouta
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Janette Mezeyova
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Matthew Waldbrook
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Richard Dean
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Thilo Focken
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Mohammad-Reza Ghovanloo
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
- Department
of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department
of Neurology, Yale University, New Haven, Connecticut 06519, United States
| | - Peter C. Ruben
- Department
of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Fiona Scott
- Neurocrine
Biosciences, San Diego, California 92130, United States
| | - Charles J. Cohen
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - James Empfield
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - JP Johnson
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
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27
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Tonggu L, Wisedchaisri G, Gamal El-Din TM, Lenaeus MJ, Logan MM, Toma T, Du Bois J, Zheng N, Catterall WA. Dual receptor-sites reveal the structural basis for hyperactivation of sodium channels by poison-dart toxin batrachotoxin. Nat Commun 2024; 15:2306. [PMID: 38485923 PMCID: PMC10940626 DOI: 10.1038/s41467-024-45958-w] [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: 10/05/2023] [Accepted: 02/08/2024] [Indexed: 03/18/2024] Open
Abstract
The poison dart toxin batrachotoxin is exceptional for its high potency and toxicity, and for its multifaceted modification of the function of voltage-gated sodium channels. By using cryogenic electron microscopy, we identify two homologous, but nonidentical receptor sites that simultaneously bind two molecules of toxin, one at the interface between Domains I and IV, and the other at the interface between Domains III and IV of the cardiac sodium channel. Together, these two bound toxin molecules stabilize α/π helical conformation in the S6 segments that gate the pore, and one of the bound BTX-B molecules interacts with the crucial Lys1421 residue that is essential for sodium conductance and selectivity via an apparent water-bridged hydrogen bond. Overall, our structure provides insight into batrachotoxin's potency, efficacy, and multifaceted functional effects on voltage-gated sodium channels via a dual receptor site mechanism.
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Affiliation(s)
- Lige Tonggu
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | | | | | - Michael J Lenaeus
- Division of General Internal Medicine, Department of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Matthew M Logan
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
- Vividion Therapeutics, Inc., 5820 Nancy Ridge Dr., San Diego, CA, 92121, USA
| | - Tatsuya Toma
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
- PRISM BioLab Co., Ltd., 2-26-1 Muraokahigashi, Fujisawa-shi, Kanagawa, 251-8555, Japan
| | - Justin Du Bois
- Department of Chemistry, Stanford University, Stanford, CA, 94305, 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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28
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Lin Y, Tao E, Champion JP, Corry B. A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels. eLife 2024; 12:RP91218. [PMID: 38465747 DOI: 10.7554/elife.91218] [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: 03/12/2024] Open
Abstract
Voltage-gated sodium channels (Naᵥ) are membrane proteins which open to facilitate the inward flux of sodium ions into excitable cells. In response to stimuli, Naᵥ channels transition from the resting, closed state to an open, conductive state, before rapidly inactivating. Dysregulation of this functional cycle due to mutations causes diseases including epilepsy, pain conditions, and cardiac disorders, making Naᵥ channels a significant pharmacological target. Phosphoinositides are important lipid cofactors for ion channel function. The phosphoinositide PI(4,5)P2 decreases Naᵥ1.4 activity by increasing the difficulty of channel opening, accelerating fast inactivation and slowing recovery from fast inactivation. Using multiscale molecular dynamics simulations, we show that PI(4,5)P2 binds stably to inactivated Naᵥ at a conserved site within the DIV S4-S5 linker, which couples the voltage-sensing domain (VSD) to the pore. As the Naᵥ C-terminal domain is proposed to also bind here during recovery from inactivation, we hypothesize that PI(4,5)P2 prolongs inactivation by competitively binding to this site. In atomistic simulations, PI(4,5)P2 reduces the mobility of both the DIV S4-S5 linker and the DIII-IV linker, responsible for fast inactivation, slowing the conformational changes required for the channel to recover to the resting state. We further show that in a resting state Naᵥ model, phosphoinositides bind to VSD gating charges, which may anchor them and impede VSD activation. Our results provide a mechanism by which phosphoinositides alter the voltage dependence of activation and the rate of recovery from inactivation, an important step for the development of novel therapies to treat Naᵥ-related diseases.
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Affiliation(s)
- Yiechang Lin
- Research School of Biology, Australian National University, Canberra, Australia
| | - Elaine Tao
- Research School of Biology, Australian National University, Canberra, Australia
| | - James P Champion
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, Australia
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29
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Lai HJ, Lee MJ, Yu HW, Chen KW, Tsai KL, Lin PC, Huang CW. Biophysical mechanisms underlying tefluthrin-induced modulation of gating changes and resurgent current generation in the human Na v1.4 channel. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 200:105833. [PMID: 38582596 DOI: 10.1016/j.pestbp.2024.105833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/14/2024] [Accepted: 02/17/2024] [Indexed: 04/08/2024]
Abstract
Human skeletal muscle contraction is triggered by activation of Nav1.4 channels. Nav1.4 channels can generate resurgent currents by channel reopening at hyperpolarized potentials through a gating transition dependent on the intracellular Navβ4 peptide in the physiological conditions. Tefluthrin (TEF) is a pyrethroid insecticide that can disrupt electrical signaling in nerves and skeletal muscle, resulting in seizures, muscle spasms, fasciculations, and mental confusion. TEF can also induce tail currents through other voltage-gated sodium channels in the absence of Navβ4 peptide, suggesting that muscle spasms may be caused by resurgent currents. Further, intracellular Navβ4 peptide and extracellular TEF may show competitive or synergistic effects; however, their binding sites are still unknown. To address these issues, electrophysiological recordings were performed on CHO-K1 cells expressing Nav1.4 channels with intracellular Navβ4 peptide, extracellular TEF, or both. TEF and Navβ4 peptide induced a hyperpolarizing shift of activation and inactivation curves in the Nav1.4 channel. TEF also substantially prolonged the inactivation time constants, while simultaneous application of Navβ4 peptide partially reversed this effect. Resurgent currents were enhanced by TEF and Navβ4 peptide at negative potentials, but TEF more potently enhances resurgent currents and dampens decay of resurgent currents. With longer depolarization, peak resurgent currents decay was fastest with the TEF alone. Molecular docking suggested that TEF and Navβ4 peptide binding site(s) are not in the narrowest part of the channel pore, but rather in the bundle-crossing regions and in the domain linkers, respectively. TEF can induce resurgent currents independently and synergistically with Navβ4 peptide, which may explain the muscle spasms observed in TEF intoxication.
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Affiliation(s)
- Hsing-Jung Lai
- Department of Neurology, National Taiwan University Hospital, Taipei 10617, Taiwan; Department of Physiology, National Taiwan University, Taipei 10617, Taiwan
| | - Ming-Jen Lee
- Department of Neurology, National Taiwan University Hospital, Taipei 10617, Taiwan; Department of Medical genetics, National Taiwan University Hospital, Taipei 10617, Taiwan
| | - Hsin-Wei Yu
- Department of Physiology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Kuan-Wen Chen
- Genetics Generation Advancement Corporation, Taipei 11494, Taiwan
| | - Ke-Li Tsai
- Department of Physiology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Pi-Chen Lin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
| | - Chiung-Wei Huang
- Department of Physiology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Post-Baccalaureate Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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30
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Li Z, Wu Q, Huang G, Jin X, Li J, Pan X, Yan N. Dissection of the structure-function relationship of Na v channels. Proc Natl Acad Sci U S A 2024; 121:e2322899121. [PMID: 38381792 PMCID: PMC10907234 DOI: 10.1073/pnas.2322899121] [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: 12/28/2023] [Accepted: 01/17/2024] [Indexed: 02/23/2024] Open
Abstract
Voltage-gated sodium channels (Nav) undergo conformational shifts in response to membrane potential changes, a mechanism known as the electromechanical coupling. To delineate the structure-function relationship of human Nav channels, we have performed systematic structural analysis using human Nav1.7 as a prototype. Guided by the structural differences between wild-type (WT) Nav1.7 and an eleven mutation-containing variant, designated Nav1.7-M11, we generated three additional intermediate mutants and solved their structures at overall resolutions of 2.9-3.4 Å. The mutant with nine-point mutations in the pore domain (PD), named Nav1.7-M9, has a reduced cavity volume and a sealed gate, with all voltage-sensing domains (VSDs) remaining up. Structural comparison of WT and Nav1.7-M9 pinpoints two residues that may be critical to the tightening of the PD. However, the variant containing these two mutations, Nav1.7-M2, or even in combination with two additional mutations in the VSDs, named Nav1.7-M4, failed to tighten the PD. Our structural analysis reveals a tendency of PD contraction correlated with the right shift of the static inactivation I-V curves. We predict that the channel in the resting state should have a "tight" PD with down VSDs.
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Affiliation(s)
- Zhangqiang Li
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Qiurong Wu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Gaoxingyu Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou310024, China
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Jiaao Li
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Xiaojing Pan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
- Institute of Bio-Architecture and Bio-Interactions, Shenzhen Medical Academy of Research and Translation, Shenzhen518107, China
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
- Institute of Bio-Architecture and Bio-Interactions, Shenzhen Medical Academy of Research and Translation, Shenzhen518107, China
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Schott K, Usher SG, Serra O, Carnevale V, Pless SA, Chua HC. Unplugging lateral fenestrations of NALCN reveals a hidden drug binding site within the pore module. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.12.536537. [PMID: 38328210 PMCID: PMC10849497 DOI: 10.1101/2023.04.12.536537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The sodium (Na + ) leak channel (NALCN) is a member of the four-domain voltage-gated cation channel family that includes the prototypical voltage-gated sodium and calcium channels (Na V s and Ca V s, respectively). Unlike Na V s and Ca V s, which have four lateral fenestrations that serve as routes for lipophilic compounds to enter the central cavity to modulate channel function, NALCN has bulky residues (W311, L588, M1145 and Y1436) that block these openings. Structural data suggest that oc-cluded lateral fenestrations underlie the pharmacological resistance of NALCN to lipophilic compounds, but functional evidence is lacking. To test this hypothesis, we unplugged the fenestrations of NALCN by substituting the four aforementioned resi-dues with alanine (AAAA) and compared the effects of Na V , Ca V and NALCN block-ers on both wild-type (WT) and AAAA channels. Most compounds behaved in a simi-lar manner on both channels, but phenytoin and 2-aminoethoxydiphenyl borate (2-APB) elicited additional, distinct responses on AAAA channels. Further experiments using single alanine mutants revealed that phenytoin and 2-APB enter the inner cav-ity through distinct fenestrations, implying structural specificity to their modes of ac-cess. Using a combination of computational and functional approaches, we identified amino acid residues critical for 2-APB activity, supporting the existence of drug bind-ing site(s) within the pore region. Intrigued by the activity of 2-APB and its ana-logues, we tested additional compounds containing the diphenylmethane/amine moiety on WT channels. We identified compounds from existing clinically used drugs that exhibited diverse activity, thus expanding the pharmacological toolbox for NALCN. While the low potencies of active compounds reiterate the resistance of NALCN to pharmacological targeting, our findings lay the foundation for rational drug design to develop NALCN modulators with refined properties. Significance statement The sodium leak channel (NALCN) is essential for survival: mutations cause life-threatening developmental disorders in humans. However, no treatment is currently available due to the resistance of NALCN to pharmacological targeting. One likely reason is that the lateral fenestrations, a common route for clinically used drugs to enter and block related ion channels, are occluded in NALCN. Using a combination of computational and functional approaches, we unplugged the fenestrations of NALCN which led us to the first molecularly defined drug binding site within the pore region. Besides that, we also identified additional NALCN modulators from existing clinically used therapeutics, thus expanding the pharmacological toolbox for this leak channel.
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32
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Seneci L, Mikheyev AS. Sodium Channel β Subunits-An Additional Element in Animal Tetrodotoxin Resistance? Int J Mol Sci 2024; 25:1478. [PMID: 38338757 PMCID: PMC10855141 DOI: 10.3390/ijms25031478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/09/2023] [Accepted: 12/15/2023] [Indexed: 02/12/2024] Open
Abstract
Tetrodotoxin (TTX) is a neurotoxic molecule used by many animals for defense and/or predation, as well as an important biomedical tool. Its ubiquity as a defensive agent has led to repeated independent evolution of tetrodotoxin resistance in animals. TTX binds to voltage-gated sodium channels (VGSC) consisting of α and β subunits. Virtually all studies investigating the mechanisms behind TTX resistance have focused on the α subunit of voltage-gated sodium channels, where tetrodotoxin binds. However, the possibility of β subunits also contributing to tetrodotoxin resistance was never explored, though these subunits act in concert. In this study, we present preliminary evidence suggesting a potential role of β subunits in the evolution of TTX resistance. We gathered mRNA sequences for all β subunit types found in vertebrates across 12 species (three TTX-resistant and nine TTX-sensitive) and tested for signatures of positive selection with a maximum likelihood approach. Our results revealed several sites experiencing positive selection in TTX-resistant taxa, though none were exclusive to those species in subunit β1, which forms a complex with the main physiological target of TTX (VGSC Nav1.4). While experimental data validating these findings would be necessary, this work suggests that deeper investigation into β subunits as potential players in tetrodotoxin resistance may be worthwhile.
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Affiliation(s)
- Lorenzo Seneci
- Adaptive Biotoxicology Lab, School of the Environment, The University of Queensland, St Lucia, QLD 4067, Australia;
| | - Alexander S. Mikheyev
- Evolutionary Genomics Group, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
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33
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Suetterlin K, Mӓnnikkӧ R, Jayaseelan DL. Inherited myotonias. HANDBOOK OF CLINICAL NEUROLOGY 2024; 203:25-38. [PMID: 39174252 DOI: 10.1016/b978-0-323-90820-7.00008-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2024]
Abstract
The inherited myotonias are a complex group of diseases caused by variations in genes that encode or modulate the expression of ion channels that regulate muscle excitability. These variations alter muscle membrane excitability allowing mild depolarization, causing myotonic discharges. There are two groups of inherited myotonia, the dystrophic and the nondystrophic myotonias (NDM). Patients with NDM have a pure muscle phenotype with variations in channel genes expressed in muscle. The dystrophic myotonias are caused by genes that alter splicing leading to more systemic effects with myotonia being one of a number of systemic symptoms. This chapter therefore focuses on the key aspects of the NDMs. The NDMs manifest with varying clinical phenotypes, which change from infancy to adulthood. The pathogenicity of different variants can be determined using heterologous expression systems to understand the alteration in channel properties and predict the likelihood of causing disease. Myotonia itself can be managed by lifestyle modifications. A number of randomized controlled trials demonstrate efficacy of mexiletine and lamotrigine in treating myotonia, but there is an evidence that specific variants may be more or less well-treated by the different agents because of how they alter the channel kinetics. More work is needed to develop more targeted genetic treatments.
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Affiliation(s)
- Karen Suetterlin
- John Walton Centre for Muscular Dystrophy and AGE Research Group, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Roope Mӓnnikkӧ
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Dipa L Jayaseelan
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom.
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Yamanouchi D, Kasuya G, Nakajo K, Kise Y, Nureki O. Dual allosteric modulation of voltage and calcium sensitivities of the Slo1-LRRC channel complex. Mol Cell 2023; 83:4555-4569.e4. [PMID: 38035882 DOI: 10.1016/j.molcel.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 09/15/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023]
Abstract
Modulation of large conductance intracellular ligand-activated potassium (BK) channel family (Slo1-3) by auxiliary subunits allows diverse physiological functions in excitable and non-excitable cells. Cryoelectron microscopy (cryo-EM) structures of voltage-gated potassium (Kv) channel complexes have provided insights into how voltage sensitivity is modulated by auxiliary subunits. However, the modulation mechanisms of BK channels, particularly as ligand-activated ion channels, remain unknown. Slo1 is a Ca2+-activated and voltage-gated BK channel and is expressed in neurons, muscle cells, and epithelial cells. Using cryo-EM and electrophysiology, we show that the LRRC26-γ1 subunit modulates not only voltage but also Ca2+ sensitivity of Homo sapiens Slo1. LRRC26 stabilizes the active conformation of voltage-senor domains of Slo1 by an extracellularly S4-locking mechanism. Furthermore, it also stabilizes the active conformation of Ca2+-sensor domains of Slo1 intracellularly, which is functionally equivalent to intracellular Ca2+ in the activation of Slo1. Such a dual allosteric modulatory mechanism may be general in regulating the intracellular ligand-activated BK channel complexes.
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Affiliation(s)
- Daichi Yamanouchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Go Kasuya
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi 329-0498, Japan.
| | - Koichi Nakajo
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi 329-0498, Japan
| | - Yoshiaki Kise
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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35
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del Carlo RE, Reimche JS, Moniz HA, Hague MT, Agarwal SR, Brodie ED, Brodie ED, Leblanc N, Feldman CR. Coevolution with toxic prey produces functional trade-offs in sodium channels of predatory snakes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.08.570760. [PMID: 38106015 PMCID: PMC10723449 DOI: 10.1101/2023.12.08.570760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Seemingly unrelated traits often share the same underlying molecular mechanisms, potentially generating a pleiotropic relationship whereby selection shaping one trait can simultaneously compromise another. While such functional trade-offs are expected to influence evolutionary outcomes, their actual relevance in nature is masked by obscure links between genotype, phenotype, and fitness. Here, we describe functional trade-offs that likely govern a key adaptation and coevolutionary dynamics in a predator-prey system. Several garter snake (Thamnophis spp.) populations have evolved resistance to tetrodotoxin (TTX), a potent chemical defense in their prey, toxic newts (Taricha spp.). Snakes achieve TTX resistance through mutations occurring at toxin-binding sites in the pore of snake skeletal muscle voltage-gated sodium channels (NaV1.4). We hypothesized that these mutations impair basic NaV functions, producing molecular trade-offs that should ultimately scale up to compromised organismal performance. We investigate biophysical costs in two snake species with unique and independently evolved mutations that confer TTX resistance. We show electrophysiological evidence that skeletal muscle sodium channels encoded by toxin-resistant alleles are functionally compromised. Furthermore, skeletal muscles from snakes with resistance genotypes exhibit reduced mechanical performance. Lastly, modeling the molecular stability of these sodium channel variants partially explains the electrophysiological and muscle impairments. Ultimately, adaptive genetic changes favoring toxin resistance appear to negatively impact sodium channel function, skeletal muscle strength, and organismal performance. These functional trade-offs at the cellular and organ levels appear to underpin locomotor deficits observed in resistant snakes and may explain variation in the population-level success of toxin-resistant alleles across the landscape, ultimately shaping the trajectory of snake-newt coevolution.
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Affiliation(s)
- Robert E. del Carlo
- University of Nevada, Reno School of Medicine, Department of Pharmacology, Reno, Nevada, USA, 89557
- University of Nevada, Reno Program in Cell & Molecular Pharmacology & Physiology
| | - Jessica S. Reimche
- University of Nevada, Reno, Department of Biology, Reno, Nevada, USA, 89557
- University of Nevada, Reno Program in Ecology, Evolution & Conservation Biology
| | - Haley A. Moniz
- University of Nevada, Reno, Department of Biology, Reno, Nevada, USA, 89557
- University of Nevada, Reno Program in Ecology, Evolution & Conservation Biology
| | - Michael T.J. Hague
- University of Virginia, Department of Biology, Charlottesville, Virginia, USA, 22904
| | - Shailesh R. Agarwal
- University of Nevada, Reno School of Medicine, Department of Pharmacology, Reno, Nevada, USA, 89557
| | - Edmund D. Brodie
- University of Virginia, Department of Biology, Charlottesville, Virginia, USA, 22904
| | - Edmund D. Brodie
- Utah State University, Department of Biology, Logan, Utah, USA, 84322
| | - Normand Leblanc
- University of Nevada, Reno School of Medicine, Department of Pharmacology, Reno, Nevada, USA, 89557
| | - Chris R. Feldman
- University of Nevada, Reno, Department of Biology, Reno, Nevada, USA, 89557
- University of Nevada, Reno Program in Ecology, Evolution & Conservation Biology
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36
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Abd-Allah WH, El-Mohsen Anwar MA, Mohammed ER, El Moghazy SM. Anticonvulsant Classes and Possible Mechanism of Actions. ACS Chem Neurosci 2023; 14:4076-4092. [PMID: 37948544 DOI: 10.1021/acschemneuro.3c00613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Abstract
Epilepsy is considered one of the most common neurological disorders worldwide; it needs long-term or life-long treatment. Despite the presence of several novel antiepileptic drugs, approximately 30% patients still suffer from drug-resistant epilepsy. Subsequently, searching for new anticonvulsants with lower toxicity and better efficacy is still in paramount demand. Using target-based studies in the discovery of novel antiepileptics is uncommon owing to the insufficient information on the molecular pathway of epilepsy and complex mode of action for most of known antiepileptic drugs. In this review, we investigated the properties of anticonvulsants, types of epileptic seizures, and mechanism of action for anticonvulsants.
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Affiliation(s)
- Walaa Hamada Abd-Allah
- Pharmaceutical Chemistry Department, Collage of Pharmaceutical Science and Drug Manufacturing, Misr University for Science and Technology, P.O. 77, 12568 6th of October City, Giza, Egypt
| | - Mostafa Abd El-Mohsen Anwar
- Pharmaceutical Chemistry Department, Collage of Pharmaceutical Science and Drug Manufacturing, Misr University for Science and Technology, P.O. 77, 12568 6th of October City, Giza, Egypt
| | - Eman R Mohammed
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, 11562 Cairo, Egypt
| | - Samir M El Moghazy
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, 11562 Cairo, Egypt
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37
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Raman IM. The Hodgkin-Huxley-Katz Prize Lecture: A Markov model with permeation-dependent gating that accounts for resurgent current of voltage-gated Na channels. J Physiol 2023; 601:5147-5164. [PMID: 37837315 PMCID: PMC10913027 DOI: 10.1113/jp285166] [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: 07/23/2023] [Accepted: 09/20/2023] [Indexed: 10/16/2023] Open
Abstract
Many neurons that fire high-frequency action potentials express specialized voltage-gated Na channel complexes that not only conduct transient current upon depolarization, but also pass resurgent current upon repolarization. The resurgent current is associated with recovery of transient current, even at moderately negative potentials where fast inactivation is usually absorbing. The combined results of many experimental studies have led to the hypothesis that resurgent current flows upon repolarization when an endogenous blocking protein that occludes open channels at depolarized potentials is expelled by inwardly permeating Na ions. Additional observations have suggested that the position of the voltage sensor of domain IV regulates the affinity of the channel for the putative blocker. To test the effectiveness of a kinetic scheme incorporating these features, here we develop and justify a Markov model with states grounded in known Na channel conformations. Simulations were designed to investigate whether including a permeation-dependent unblocking rate constant and two open-blocked states, superimposed on conformations and voltage-sensitive movements present in all voltage-gated Na channels, is sufficient to account for the unusual gating of channels with a resurgent component. Optimizing rate constant parameters against a wide range of experimental data from cerebellar Purkinje cells demonstrates that a kinetic scheme for Na channels incorporating the novel aspects of a permeation-dependent unblock, as well as distinct high- and low-affinity blocked states, reproduces all the attributes of experimentally recorded Na currents in a physiologically plausible manner.
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Affiliation(s)
- Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
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38
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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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39
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Spafford JD. A governance of ion selectivity based on the occupancy of the "beacon" in one- and four-domain calcium and sodium channels. Channels (Austin) 2023; 17:2191773. [PMID: 37075164 PMCID: PMC10120453 DOI: 10.1080/19336950.2023.2191773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
One of nature's exceptions was discovered when a Cav3 T-type channel was observed to switch phenotype from a calcium channel into a sodium channel by neutralizing an aspartate residue in the high field strength (HFS) +1 position within the ion selectivity filter. The HFS+1 site is dubbed a "beacon" for its location at the entryway just above the constricted, minimum radius of the HFS site's electronegative ring. A classification is proposed based on the occupancy of the HFS+1 "beacon" which correlates with the calcium- or sodium-selectivity phenotype. If the beacon is a glycine, or neutral, non-glycine residue, then the cation channel is calcium-selective or sodium-permeable, respectively (Class I). Occupancy of a beacon aspartate are calcium-selective channels (Class II) or possessing a strong calcium block (Class III). A residue lacking in position of the sequence alignment for the beacon are sodium channels (Class IV). The extent to which animal channels are sodium-selective is dictated in the occupancy of the HFS site with a lysine residue (Class III/IV). Governance involving the beacon solves the quandary the HFS site as a basis for ion selectivity, where an electronegative ring of glutamates at the HFS site generates a sodium-selective channel in one-domain channels but generates a calcium-selective channel in four-domain channels. Discovery of a splice variant in an exceptional channel revealed nature's exploits, highlighting the "beacon" as a principal determinant for calcium and sodium selectivity, encompassing known ion channels composed of one and four domains, from bacteria to animals.
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Affiliation(s)
- J David Spafford
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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40
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Gao S, Yao X, Chen J, Huang G, Fan X, Xue L, Li Z, Wu T, Zheng Y, Huang J, Jin X, Wang Y, Wang Z, Yu Y, Liu L, Pan X, Song C, Yan N. Structural basis for human Ca v1.2 inhibition by multiple drugs and the neurotoxin calciseptine. Cell 2023; 186:5363-5374.e16. [PMID: 37972591 DOI: 10.1016/j.cell.2023.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/16/2023] [Accepted: 10/04/2023] [Indexed: 11/19/2023]
Abstract
Cav1.2 channels play crucial roles in various neuronal and physiological processes. Here, we present cryo-EM structures of human Cav1.2, both in its apo form and in complex with several drugs, as well as the peptide neurotoxin calciseptine. Most structures, apo or bound to calciseptine, amlodipine, or a combination of amiodarone and sofosbuvir, exhibit a consistent inactivated conformation with a sealed gate, three up voltage-sensing domains (VSDs), and a down VSDII. Calciseptine sits on the shoulder of the pore domain, away from the permeation path. In contrast, when pinaverium bromide, an antispasmodic drug, is inserted into a cavity reminiscent of the IFM-binding site in Nav channels, a series of structural changes occur, including upward movement of VSDII coupled with dilation of the selectivity filter and its surrounding segments in repeat III. Meanwhile, S4-5III merges with S5III to become a single helix, resulting in a widened but still non-conductive intracellular gate.
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Affiliation(s)
- Shuai Gao
- Department of Urology, Zhongnan Hospital of Wuhan University, TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Xia Yao
- Department of Urology, Zhongnan Hospital of Wuhan University, TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jiaofeng Chen
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, Zhejiang Provincial Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Lingfeng Xue
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Zhangqiang Li
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tong Wu
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yupeng Zheng
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yan Wang
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Zhifei Wang
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Yong Yu
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Lei Liu
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xiaojing Pan
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong 518107, China
| | - Chen Song
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong 518107, China.
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41
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Finkelstein DS, Du Bois J. Trifunctional Saxitoxin Conjugates for Covalent Labeling of Voltage-Gated Sodium Channels. Chembiochem 2023; 24:e202300493. [PMID: 37746898 PMCID: PMC10863845 DOI: 10.1002/cbic.202300493] [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: 07/04/2023] [Revised: 08/24/2023] [Indexed: 09/26/2023]
Abstract
Voltage-gated sodium ion channels (NaV s) are integral membrane protein complexes responsible for electrical signal conduction in excitable cells. Methods that enable selective labeling of NaV s hold potential value for understanding how channel regulation and post-translational modification are influenced during development and in response to diseases and disorders of the nervous system. We have developed chemical reagents patterned after (+)-saxitoxin (STX) - a potent and reversible inhibitor of multiple NaV isoforms - and affixed with a reactive electrophile and either a biotin cofactor, fluorophore, or 'click' functional group for labeling wild-type channels. Our studies reveal enigmatic structural effects of the probes on the potency and efficiency of covalent protein modification. Among the compounds analyzed, a STX-maleimide-coumarin derivative is most effective at irreversibly blocking Na+ conductance when applied to recombinant NaV s and endogenous channels expressed in hippocampal neurons. Mechanistic analysis supports the conclusion that high-affinity toxin binding is a prerequisite for covalent protein modification. Results from these studies are guiding the development of next-generation tool compounds for selective modification of NaV s expressed in the plasma membranes of cells.
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Affiliation(s)
- Darren S Finkelstein
- Department of Chemistry, Stanford University, 337 Campus Dr., Stanford, CA 94305, USA
- Present address: Pliant Therapeutics, 260 Littlefield Avenue, South San Francisco, CA 94080, USA
| | - J Du Bois
- Department of Chemistry, Stanford University, 337 Campus Dr., Stanford, CA 94305, USA
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42
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Bian Y, Tuo J, He L, Li W, Li S, Chu H, Zhao Y. Voltage-gated sodium channels in cancer and their specific inhibitors. Pathol Res Pract 2023; 251:154909. [PMID: 37939447 DOI: 10.1016/j.prp.2023.154909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/10/2023]
Abstract
Voltage-gated sodium channels (VGSCs) participate in generating and spreading action potentials in electrically excited cells such as neurons and muscle fibers. Abnormal expression of VGSCs has been observed in various types of tumors, while they are either not expressed or expressed at a low level in the matching normal tissue. Hence, this abnormal expression suggests that VGSCs confer some advantage or viability on tumor cells, making them a valuable indicator for identifying tumor cells. In addition, overexpression of VGSCs increased the ability of cancer cells to metastasize and invade, as well as correlated with the metastatic behavior of different cancers. Therefore, blocking VGSCs presents a new strategy for the treatment of cancers. A portion of this review summarizes the structure and function of VGSCs and also describes the correlation between VGSCs and cancers. Most importantly, we provide an overview of current research on various subtype-selective VGSC inhibitors and updates on ongoing clinical studies.
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Affiliation(s)
- Yuan Bian
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Jiale Tuo
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Liangpeng He
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Wenwen Li
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China
| | - Shangxiao Li
- School of Medical Devices, Shenyang Pharmaceutical University, Benxi, Liaoning 117004, PR China
| | - Huiying Chu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Yongshan Zhao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, PR China.
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Ali NH, Al-Kuraishy HM, Al-Gareeb AI, Alnaaim SA, Alexiou A, Papadakis M, Saad HM, Batiha GES. Autophagy and autophagy signaling in Epilepsy: possible role of autophagy activator. Mol Med 2023; 29:142. [PMID: 37880579 PMCID: PMC10598971 DOI: 10.1186/s10020-023-00742-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023] Open
Abstract
Autophagy is an explicit cellular process to deliver dissimilar cytoplasmic misfolded proteins, lipids and damaged organelles to the lysosomes for degradation and elimination. The mechanistic target of rapamycin (mTOR) is the main negative regulator of autophagy. The mTOR pathway is involved in regulating neurogenesis, synaptic plasticity, neuronal development and excitability. Exaggerated mTOR activity is associated with the development of temporal lobe epilepsy, genetic and acquired epilepsy, and experimental epilepsy. In particular, mTOR complex 1 (mTORC1) is mainly involved in epileptogenesis. The investigation of autophagy's involvement in epilepsy has recently been conducted, focusing on the critical role of rapamycin, an autophagy inducer, in reducing the severity of induced seizures in animal model studies. The induction of autophagy could be an innovative therapeutic strategy in managing epilepsy. Despite the protective role of autophagy against epileptogenesis and epilepsy, its role in status epilepticus (SE) is perplexing and might be beneficial or detrimental. Therefore, the present review aims to revise the possible role of autophagy in epilepsy.
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Affiliation(s)
- Naif H Ali
- Department of Internal Medicine, Medical College, Najran university, Najran, Saudi Arabia
| | - Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, P.O. Box 14132, Baghdad, Iraq
| | - Ali I Al-Gareeb
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, P.O. Box 14132, Baghdad, Iraq
| | - Saud A Alnaaim
- Clinical Neurosciences Department, College of Medicine, King Faisal University, Hofuf, Saudi Arabia
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, Wien, 1030, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Heusnerstrasse 40, 42283, Wuppertal, Germany.
| | - Hebatallah M Saad
- Department of Pathology, Faculty of Veterinary Medicine, Matrouh University, Matrouh, Matrouh, 51744, Egypt.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt.
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44
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Huang J, Fan X, Jin X, Teng L, Yan N. Dual-pocket inhibition of Na v channels by the antiepileptic drug lamotrigine. Proc Natl Acad Sci U S A 2023; 120:e2309773120. [PMID: 37782796 PMCID: PMC10576118 DOI: 10.1073/pnas.2309773120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/01/2023] [Indexed: 10/04/2023] Open
Abstract
Voltage-gated sodium (Nav) channels govern membrane excitability, thus setting the foundation for various physiological and neuronal processes. Nav channels serve as the primary targets for several classes of widely used and investigational drugs, including local anesthetics, antiepileptic drugs, antiarrhythmics, and analgesics. In this study, we present cryogenic electron microscopy (cryo-EM) structures of human Nav1.7 bound to two clinical drugs, riluzole (RLZ) and lamotrigine (LTG), at resolutions of 2.9 Å and 2.7 Å, respectively. A 3D EM reconstruction of ligand-free Nav1.7 was also obtained at 2.1 Å resolution. RLZ resides in the central cavity of the pore domain and is coordinated by residues from repeats III and IV. Whereas one LTG molecule also binds to the central cavity, the other is found beneath the intracellular gate, known as site BIG. Therefore, LTG, similar to lacosamide and cannabidiol, blocks Nav channels via a dual-pocket mechanism. These structures, complemented with docking and mutational analyses, also explain the structure-activity relationships of the LTG-related linear 6,6 series that have been developed for improved efficacy and subtype specificity on different Nav channels. Our findings reveal the molecular basis for these drugs' mechanism of action and will aid the development of novel antiepileptic and pain-relieving drugs.
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Affiliation(s)
- Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ08544
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ08544
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Liming Teng
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ08544
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
- Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong Province518107, China
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45
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Raisch T, Raunser S. The modes of action of ion-channel-targeting neurotoxic insecticides: lessons from structural biology. Nat Struct Mol Biol 2023; 30:1411-1427. [PMID: 37845413 DOI: 10.1038/s41594-023-01113-5] [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: 11/23/2022] [Accepted: 08/31/2023] [Indexed: 10/18/2023]
Abstract
Insecticides are indispensable tools for plant protection in modern agriculture. Despite having highly heterogeneous structures, many neurotoxic insecticides use similar principles to inhibit or deregulate neuronal ion channels. Insecticides targeting pentameric ligand-gated channels are structural mimetics of neurotransmitters or manipulate and deregulate the proteins. Those binding to (pseudo-)tetrameric voltage-gated(-like) channels, on the other hand, are natural or synthetic compounds that directly block the ion-conducting pore or prevent conformational changes in the transmembrane domain necessary for opening and closing the pore. The use of a limited number of inhibition mechanisms can be problematic when resistances arise and become more widespread. Therefore, there is a rising interest in the development of insecticides with novel mechanisms that evade resistance and are pest-insect-specific. During the last decade, most known insecticide targets, many with bound compounds, have been structurally characterized, bringing the rational design of novel classes of agrochemicals within closer reach than ever before.
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Affiliation(s)
- Tobias Raisch
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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Hussein RA, Ahmed M, Heinemann SH. Selenomethionine mis-incorporation and redox-dependent voltage-gated sodium channel gain of function. J Neurochem 2023; 167:262-276. [PMID: 37679952 DOI: 10.1111/jnc.15957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023]
Abstract
Selenomethionine (SeMet) readily replaces methionine (Met) residues in proteins during translation. Long-term dietary SeMet intake results in the accumulation of the amino acid in tissue proteins. Despite the high rates of SeMet incorporation in proteins and its stronger susceptibility to oxidation compared to Met, little is known about the effect of SeMet mis-incorporation on electrical excitability and ion channels. Fast inactivation of voltage-gated sodium (NaV ) channels is essential for exact action potential shaping with even minute impairment of inactivation resulting in a plethora of adverse phenotypes. Met oxidation of the NaV channel inactivation motif (Ile-Phe-Met) and further Met residues causes a marked loss of inactivation. Here, we examined the impact of SeMet mis-incorporation on the function of NaV channels. While extensive SeMet incorporation into recombinant rat NaV 1.4 channels preserved their normal function, it greatly sensitized the channels to mild oxidative stress, resulting in loss of inactivation and diminished maximal current, both reversible by dithiothreitol-induced reduction. SeMet incorporation similarly affected human NaV 1.4, NaV 1.2, NaV 1.5, and NaV 1.7. In mouse dorsal root ganglia (DRG) neurons, 1 day of SeMet exposure exacerbated the oxidation-mediated broadening of action potentials. SeMet-treated DRGs also exhibited a stronger increase in the persistent NaV current in response to oxidation. SeMet incorporation in NaV proteins coinciding with oxidative insults may therefore result in hyperexcitability pathologies, such as cardiac arrhythmias and neuropathies, like congenital NaV channel gain-of-function mutations.
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Affiliation(s)
- Rama A Hussein
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| | - Marwa Ahmed
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
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Fernández-Mariño AI, Tan XF, Bae C, Huffer K, Jiang J, Swartz KJ. Inactivation of the Kv2.1 channel through electromechanical coupling. Nature 2023; 622:410-417. [PMID: 37758949 PMCID: PMC10567553 DOI: 10.1038/s41586-023-06582-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
The Kv2.1 voltage-activated potassium (Kv) channel is a prominent delayed-rectifier Kv channel in the mammalian central nervous system, where its mechanisms of activation and inactivation are critical for regulating intrinsic neuronal excitability1,2. Here we present structures of the Kv2.1 channel in a lipid environment using cryo-electron microscopy to provide a framework for exploring its functional mechanisms and how mutations causing epileptic encephalopathies3-7 alter channel activity. By studying a series of disease-causing mutations, we identified one that illuminates a hydrophobic coupling nexus near the internal end of the pore that is critical for inactivation. Both functional and structural studies reveal that inactivation in Kv2.1 results from dynamic alterations in electromechanical coupling to reposition pore-lining S6 helices and close the internal pore. Consideration of these findings along with available structures for other Kv channels, as well as voltage-activated sodium and calcium channels, suggests that related mechanisms of inactivation are conserved in voltage-activated cation channels and likely to be engaged by widely used therapeutics to achieve state-dependent regulation of channel activity.
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Affiliation(s)
- Ana I Fernández-Mariño
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Xiao-Feng Tan
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Chanhyung Bae
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Kate Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jiansen Jiang
- Laboratory of Membrane Proteins and Structural Biology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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Brenes O, Pusch M, Morales F. ClC-1 Chloride Channel: Inputs on the Structure-Function Relationship of Myotonia Congenita-Causing Mutations. Biomedicines 2023; 11:2622. [PMID: 37892996 PMCID: PMC10604815 DOI: 10.3390/biomedicines11102622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 10/29/2023] Open
Abstract
Myotonia congenita is a hereditary muscle disease mainly characterized by muscle hyperexcitability, which leads to a sustained burst of discharges that correlates with the magnitude and duration of involuntary aftercontractions, muscle stiffness, and hypertrophy. Mutations in the chloride voltage-gated channel 1 (CLCN1) gene that encodes the skeletal muscle chloride channel (ClC-1) are responsible for this disease, which is commonly known as myotonic chloride channelopathy. The biophysical properties of the mutated channel have been explored and analyzed through in vitro approaches, providing important clues to the general function/dysfunction of the wild-type and mutated channels. After an exhaustive search for CLCN1 mutations, we report in this review more than 350 different mutations identified in the literature. We start discussing the physiological role of the ClC-1 channel in skeletal muscle functioning. Then, using the reported functional effects of the naturally occurring mutations, we describe the biophysical and structural characteristics of the ClC-1 channel to update the knowledge of the function of each of the ClC-1 helices, and finally, we attempt to point out some patterns regarding the effects of mutations in the different helices and loops of the protein.
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Affiliation(s)
- Oscar Brenes
- Departamento de Fisiología, Escuela de Medicina, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
- Centro de Investigación en Neurociencias (CIN), Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, San José 11501-2060, Costa Rica
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Ahangar AA, Elhanafy E, Blanton H, Li J. Mapping Structural Distribution and Gating-Property Impacts of Disease-Associated Missense Mutations in Voltage-Gated Sodium Channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558623. [PMID: 37781633 PMCID: PMC10541146 DOI: 10.1101/2023.09.20.558623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Thousands of voltage-gated sodium (Nav) channel variants contribute to a variety of disorders, including epilepsy, autism, cardiac arrhythmia, and pain disorders. Yet variant effects of more mutations remain unclear. The conventional gain-of-function (GoF) or loss-of-function (LoF) classifications is frequently employed to interpret of variant effects on function and guide precision therapy for sodium channelopathies. Our study challenges this binary classification by analyzing 525 mutations associated with 34 diseases across 366 electrophysiology studies, revealing that diseases with similar phenotypic effects can stem from unique molecular mechanisms. Our results show a high biophysical agreement (86%) between homologous disease-associated variants in different Nav genes, significantly surpassing the 60% phenotype (GoFo/LoFo) agreement among homologous mutants, suggesting the need for more nuanced disease categorization and treatment based on specific gating-property changes. Using UniProt data, we mapped over 2,400 disease-associated missense variants across nine human Nav channels and identified three clusters of mutation hotspots. Our findings indicate that mutations near the selectivity filter generally diminish the maximal current amplitude, while those in the fast inactivation region lean towards a depolarizing shift in half-inactivation voltage in steady-state activation, and mutations in the activation gate commonly enhance persistent current. In contrast to mutations in the PD, those within the VSD exhibit diverse impacts and subtle preferences on channel activity. This study shows great potential to enhance prediction accuracy for variant effects based on the structural context, laying the groundwork for targeted drug design in precision medicine.
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Affiliation(s)
- Amin Akbari Ahangar
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi
| | - Eslam Elhanafy
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi
| | - Hayden Blanton
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi
| | - Jing Li
- Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi
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50
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Zhang X, Mei LC, Gao YY, Hao GF, Song BA. Web tools support predicting protein-nucleic acid complexes stability with affinity changes. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1781. [PMID: 36693636 DOI: 10.1002/wrna.1781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/10/2022] [Accepted: 11/28/2022] [Indexed: 01/26/2023]
Abstract
Numerous biological processes, such as transcription, replication, and translation, rely on protein-nucleic acid interactions (PNIs). Demonstrating the binding stability of protein-nucleic acid complexes is vital to deciphering the code for PNIs. Numerous web-based tools have been developed to attach importance to protein-nucleic acid stability, facilitating the prediction of PNIs characteristics rapidly. However, the data and tools are dispersed and lack comprehensive integration to understand the stability of PNIs better. In this review, we first summarize existing databases for evaluating the stability of protein-nucleic acid binding. Then, we compare and evaluate the pros and cons of web tools for forecasting the interaction energies of protein-nucleic acid complexes. Finally, we discuss the application of combining models and capabilities of PNIs. We may hope these web-based tools will facilitate the discovery of recognition mechanisms for protein-nucleic acid binding stability. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Xiao Zhang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, China
| | - Long-Can Mei
- National Key Laboratory of Green Pesticide, Central China Normal University, Wuhan, China
| | - Yang-Yang Gao
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, China
| | - Ge-Fei Hao
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, China
- National Key Laboratory of Green Pesticide, Central China Normal University, Wuhan, China
| | - Bao-An Song
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, China
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