1
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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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2
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Salvage SC, Jeevaratnam K, Huang CL, Jackson AP. Cardiac sodium channel complexes and arrhythmia: structural and functional roles of the β1 and β3 subunits. J Physiol 2023; 601:923-940. [PMID: 36354758 PMCID: PMC10953345 DOI: 10.1113/jp283085] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/04/2022] [Indexed: 11/12/2022] Open
Abstract
In cardiac myocytes, the voltage-gated sodium channel NaV 1.5 opens in response to membrane depolarisation and initiates the action potential. The NaV 1.5 channel is typically associated with regulatory β-subunits that modify gating and trafficking behaviour. These β-subunits contain a single extracellular immunoglobulin (Ig) domain, a single transmembrane α-helix and an intracellular region. Here we focus on the role of the β1 and β3 subunits in regulating NaV 1.5. We catalogue β1 and β3 domain specific mutations that have been associated with inherited cardiac arrhythmia, including Brugada syndrome, long QT syndrome, atrial fibrillation and sudden death. We discuss how new structural insights into these proteins raises new questions about physiological function.
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Affiliation(s)
| | | | - Christopher L.‐H. Huang
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Department of PhysiologyDevelopment and NeuroscienceUniversity of CambridgeCambridgeUK
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3
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Jiang D, Zhang J, Xia Z. Structural Advances in Voltage-Gated Sodium Channels. Front Pharmacol 2022; 13:908867. [PMID: 35721169 PMCID: PMC9204039 DOI: 10.3389/fphar.2022.908867] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are responsible for the rapid rising-phase of action potentials in excitable cells. Over 1,000 mutations in NaV channels are associated with human diseases including epilepsy, periodic paralysis, arrhythmias and pain disorders. Natural toxins and clinically-used small-molecule drugs bind to NaV channels and modulate their functions. Recent advances from cryo-electron microscopy (cryo-EM) structures of NaV channels reveal invaluable insights into the architecture, activation, fast inactivation, electromechanical coupling, ligand modulation and pharmacology of eukaryotic NaV channels. These structural analyses not only demonstrate molecular mechanisms for NaV channel structure and function, but also provide atomic level templates for rational development of potential subtype-selective therapeutics. In this review, we summarize recent structural advances of eukaryotic NaV channels, highlighting the structural features of eukaryotic NaV channels as well as distinct modulation mechanisms by a wide range of modulators from natural toxins to synthetic small-molecules.
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Affiliation(s)
- Daohua Jiang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Daohua Jiang,
| | - Jiangtao Zhang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhanyi Xia
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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4
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Poly-dipeptides produced from C9orf72 hexanucleotide repeats cause selective motor neuron hyperexcitability in ALS. Proc Natl Acad Sci U S A 2022; 119:e2113813119. [PMID: 35259014 PMCID: PMC8931230 DOI: 10.1073/pnas.2113813119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
SignificanceThe GGGGCC hexanucleotide repeat expansion in the chromosome 9 open reading frame 72 (C9orf72) gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS). Despite myriad studies on the toxic effects of poly-dipeptides produced from the C9orf72 repeats, the mechanisms underlying the selective hyperexcitability of motor cortex that characterizes the early stages of C9orf72 ALS patients remain elusive. Here, we show that the proline-arginine poly-dipeptides cause hyperexcitability in cortical motor neurons by increasing persistent sodium currents conducted by the Nav1.2/β4 sodium channel complex, which is highly expressed in the motor cortex. These findings provide the basis for understanding how the C9orf72 mutation causes motor neuron hyperactivation that can lead to the motor neuron death in C9orf72 ALS.
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5
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Abderemane-Ali F, Rossen ND, Kobiela ME, Craig RA, Garrison CE, Chen Z, Colleran CM, O’Connell LA, Du Bois J, Dumbacher JP, Minor DL. Evidence that toxin resistance in poison birds and frogs is not rooted in sodium channel mutations and may rely on "toxin sponge" proteins. J Gen Physiol 2021; 153:e202112872. [PMID: 34351379 PMCID: PMC8348241 DOI: 10.1085/jgp.202112872] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/30/2021] [Accepted: 07/01/2021] [Indexed: 12/18/2022] Open
Abstract
Many poisonous organisms carry small-molecule toxins that alter voltage-gated sodium channel (NaV) function. Among these, batrachotoxin (BTX) from Pitohui poison birds and Phyllobates poison frogs stands out because of its lethality and unusual effects on NaV function. How these toxin-bearing organisms avoid autointoxication remains poorly understood. In poison frogs, a NaV DIVS6 pore-forming helix N-to-T mutation has been proposed as the BTX resistance mechanism. Here, we show that this variant is absent from Pitohui and poison frog NaVs, incurs a strong cost compromising channel function, and fails to produce BTX-resistant channels in poison frog NaVs. We also show that captivity-raised poison frogs are resistant to two NaV-directed toxins, BTX and saxitoxin (STX), even though they bear NaVs sensitive to both. Moreover, we demonstrate that the amphibian STX "toxin sponge" protein saxiphilin is able to protect and rescue NaVs from block by STX. Taken together, our data contradict the hypothesis that BTX autoresistance is rooted in the DIVS6 N→T mutation, challenge the idea that ion channel mutations are a primary driver of toxin resistance, and suggest the possibility that toxin sequestration mechanisms may be key for protecting poisonous species from the action of small-molecule toxins.
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Affiliation(s)
- Fayal Abderemane-Ali
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Nathan D. Rossen
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Megan E. Kobiela
- School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE
| | | | | | - Zhou Chen
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Claire M. Colleran
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | | | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, CA
| | - John P. Dumbacher
- Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA
- Department of Biology, San Francisco State University, San Francisco, CA
| | - Daniel L. Minor
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA
- California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA
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6
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Structural Pharmacology of Voltage-Gated Sodium Channels. J Mol Biol 2021; 433:166967. [PMID: 33794261 DOI: 10.1016/j.jmb.2021.166967] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (NaV) channels initiate and propagate action potentials in excitable tissues to mediate key physiological processes including heart contraction and nervous system function. Accordingly, NaV channels are major targets for drugs, toxins and disease-causing mutations. Recent breakthroughs in cryo-electron microscopy have led to the visualization of human NaV1.1, NaV1.2, NaV1.4, NaV1.5 and NaV1.7 channel subtypes at high-resolution. These landmark studies have greatly advanced our structural understanding of channel architecture, ion selectivity, voltage-sensing, electromechanical coupling, fast inactivation, and the molecular basis underlying NaV channelopathies. NaV channel structures have also been increasingly determined in complex with toxin and small molecule modulators that target either the pore module or voltage sensor domains. These structural studies have provided new insights into the mechanisms of pharmacological action and opportunities for subtype-selective NaV channel drug design. This review will highlight the structural pharmacology of human NaV channels as well as the potential use of engineered and chimeric channels in future drug discovery efforts.
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7
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Llongueras JP, Das S, De Waele J, Capulzini L, Sorgente A, Van Petegem F, Bosmans F. Biophysical Investigation of Sodium Channel Interaction with β-Subunit Variants Associated with Arrhythmias. Bioelectricity 2020; 2:269-278. [PMID: 34476357 DOI: 10.1089/bioe.2020.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Voltage-gated sodium (NaV) channels help regulate electrical activity of the plasma membrane. Mutations in associated subunits can result in pathological outcomes. Here we examined the interaction of NaV channels with cardiac arrhythmia-linked mutations in SCN2B and SCN4B, two genes that encode auxiliary β-subunits. Materials and Methods: To investigate changes in SCN2B R137H and SCN4B I80T function, we combined three-dimensional X-ray crystallography with electrophysiological measurements on NaV1.5, the dominant subtype in the heart. Results: SCN4B I80T alters channel activity, whereas SCN2B R137H does not have an apparent effect. Structurally, the SCN4B I80T perturbation alters hydrophobic packing of the subunit with major structural changes and causes a thermal destabilization of the folding. In contrast, SCN2B R137H leads to structural changes but overall protein stability is unaffected. Conclusion: SCN4B I80T data suggest a functionally important region in the interaction between NaV1.5 and β4 that, when disrupted, could lead to channel dysfunction. A lack of apparent functional effects of SCN2B R137H on NaV1.5 suggests an alternative working mechanism, possibly through other NaV channel subtypes present in heart tissue. Indeed, mapping the structural variations of SCN2B R137H onto neuronal NaV channel structures suggests altered interaction patterns.
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Affiliation(s)
- José P Llongueras
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Samir Das
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.,Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Jolien De Waele
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Lucio Capulzini
- Arrhythmia and Electrophysiology Center, Department of Cardiology, Epicura Hospitalier Center, Hornu, Belgium
| | - Antonio Sorgente
- Arrhythmia and Electrophysiology Center, Department of Cardiology, Epicura Hospitalier Center, Hornu, 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, Ghent University, Ghent, Belgium
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8
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Chemometric Models of Differential Amino Acids at the Na vα and Na vβ Interface of Mammalian Sodium Channel Isoforms. Molecules 2020; 25:molecules25153551. [PMID: 32756517 PMCID: PMC7435598 DOI: 10.3390/molecules25153551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 12/19/2022] Open
Abstract
(1) Background: voltage-gated sodium channels (Navs) are integral membrane proteins that allow the sodium ion flux into the excitable cells and initiate the action potential. They comprise an α (Navα) subunit that forms the channel pore and are coupled to one or more auxiliary β (Navβ) subunits that modulate the gating to a variable extent. (2) Methods: after performing homology in silico modeling for all nine isoforms (Nav1.1α to Nav1.9α), the Navα and Navβ protein-protein interaction (PPI) was analyzed chemometrically based on the primary and secondary structures as well as topological or spatial mapping. (3) Results: our findings reveal a unique isoform-specific correspondence between certain segments of the extracellular loops of the Navα subunits. Precisely, loop S5 in domain I forms part of the PPI and assists Navβ1 or Navβ3 on all nine mammalian isoforms. The implied molecular movements resemble macroscopic springs, all of which explains published voltage sensor effects on sodium channel fast inactivation in gating. (4) Conclusions: currently, the specific functions exerted by the Navβ1 or Navβ3 subunits on the modulation of Navα gating remain unknown. Our work determined functional interaction in the extracellular domains on theoretical grounds and we propose a schematic model of the gating mechanism of fast channel sodium current inactivation by educated guessing.
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9
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Salvage SC, Huang CLH, Jackson AP. Cell-Adhesion Properties of β-Subunits in the Regulation of Cardiomyocyte Sodium Channels. Biomolecules 2020; 10:biom10070989. [PMID: 32630316 PMCID: PMC7407995 DOI: 10.3390/biom10070989] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 12/17/2022] Open
Abstract
Voltage-gated sodium (Nav) channels drive the rising phase of the action potential, essential for electrical signalling in nerves and muscles. The Nav channel α-subunit contains the ion-selective pore. In the cardiomyocyte, Nav1.5 is the main Nav channel α-subunit isoform, with a smaller expression of neuronal Nav channels. Four distinct regulatory β-subunits (β1–4) bind to the Nav channel α-subunits. Previous work has emphasised the β-subunits as direct Nav channel gating modulators. However, there is now increasing appreciation of additional roles played by these subunits. In this review, we focus on β-subunits as homophilic and heterophilic cell-adhesion molecules and the implications for cardiomyocyte function. Based on recent cryogenic electron microscopy (cryo-EM) data, we suggest that the β-subunits interact with Nav1.5 in a different way from their binding to other Nav channel isoforms. We believe this feature may facilitate trans-cell-adhesion between β1-associated Nav1.5 subunits on the intercalated disc and promote ephaptic conduction between cardiomyocytes.
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Affiliation(s)
- Samantha C. Salvage
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Correspondence: (S.C.S.); (A.P.J.); Tel.: +44-1223-765950 (S.C.S.); +44-1223-765951 (A.P.J.)
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Antony P. Jackson
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Correspondence: (S.C.S.); (A.P.J.); Tel.: +44-1223-765950 (S.C.S.); +44-1223-765951 (A.P.J.)
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10
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Alsaloum M, Estacion M, Almomani R, Gerrits MM, Bönhof GJ, Ziegler D, Malik R, Ferdousi M, Lauria G, Merkies IS, Faber CG, Dib-Hajj S, Waxman SG. A gain-of-function sodium channel β2-subunit mutation in painful diabetic neuropathy. Mol Pain 2020; 15:1744806919849802. [PMID: 31041876 PMCID: PMC6510061 DOI: 10.1177/1744806919849802] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Diabetes mellitus is a global challenge with many diverse health sequelae, of which diabetic peripheral neuropathy is one of the most common. A substantial number of patients with diabetic peripheral neuropathy develop chronic pain, but the genetic and epigenetic factors that predispose diabetic peripheral neuropathy patients to develop neuropathic pain are poorly understood. Recent targeted genetic studies have identified mutations in α-subunits of voltage-gated sodium channels (Navs) in patients with painful diabetic peripheral neuropathy. Mutations in proteins that regulate trafficking or functional properties of Navs could expand the spectrum of patients with Nav-related peripheral neuropathies. The auxiliary sodium channel β-subunits (β1–4) have been reported to increase current density, alter inactivation kinetics, and modulate subcellular localization of Nav. Mutations in β-subunits have been associated with several diseases, including epilepsy, cancer, and diseases of the cardiac conducting system. However, mutations in β-subunits have never been shown previously to contribute to neuropathic pain. We report here a patient with painful diabetic peripheral neuropathy and negative genetic screening for mutations in SCN9A, SCN10A, and SCN11A—genes encoding sodium channel α-subunit that have been previously linked to the development of neuropathic pain. Genetic analysis revealed an aspartic acid to asparagine mutation, D109N, in the β2-subunit. Functional analysis using current-clamp revealed that the β2-D109N rendered dorsal root ganglion neurons hyperexcitable, especially in response to repetitive stimulation. Underlying the hyperexcitability induced by the β2-subunit mutation, as evidenced by voltage-clamp analysis, we found a depolarizing shift in the voltage dependence of Nav1.7 fast inactivation and reduced use-dependent inhibition of the Nav1.7 channel.
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Affiliation(s)
- Matthew Alsaloum
- 1 Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,2 Center for Neuroscience and Regeneration Research, Veterans Affairs Medical Center, West Haven, CT, USA.,3 Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT, USA
| | - Mark Estacion
- 1 Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,2 Center for Neuroscience and Regeneration Research, Veterans Affairs Medical Center, West Haven, CT, USA
| | - Rowida Almomani
- 4 Department of Clinical Genomics, University Medical Center Maastricht, Maastricht, the Netherlands.,5 Department of Medical Laboratory Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Monique M Gerrits
- 4 Department of Clinical Genomics, University Medical Center Maastricht, Maastricht, the Netherlands.,6 Department of Neurology, University Medical Centre Maastricht, Maastricht, the Netherlands
| | - Gidon J Bönhof
- 7 Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
| | - Dan Ziegler
- 7 Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany.,1 8German Center for Diabetes Research, München-Neuherberg, Germany.,9 Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Rayaz Malik
- 10 Weill Cornell Medicine-Qatar, Doha, Qatar.,11 Division of Diabetes, Endocrinology and Gastroenterology, Institute of Human Development, University of Manchester, Manchester, UK
| | - Maryam Ferdousi
- 11 Division of Diabetes, Endocrinology and Gastroenterology, Institute of Human Development, University of Manchester, Manchester, UK
| | - Giuseppe Lauria
- 12 Neuroalgology Unit, IRCCS Foundation "Carlo Besta" Neurological Institute, Milan, Italy.,13 Department of Biomedical and Clinical Sciences "Luigi Sacco," University of Milan, Milan, Italy
| | - Ingemar Sj Merkies
- 6 Department of Neurology, University Medical Centre Maastricht, Maastricht, the Netherlands.,14 Department of Neurology, St. Elisabeth Hospital, Willemstad, Curaçao
| | - Catharina G Faber
- 6 Department of Neurology, University Medical Centre Maastricht, Maastricht, the Netherlands
| | - Sulayman Dib-Hajj
- 1 Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,2 Center for Neuroscience and Regeneration Research, Veterans Affairs Medical Center, West Haven, CT, USA
| | - Stephen G Waxman
- 1 Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,2 Center for Neuroscience and Regeneration Research, Veterans Affairs Medical Center, West Haven, CT, USA
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11
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Cortada E, Brugada R, Verges M. Trafficking and Function of the Voltage-Gated Sodium Channel β2 Subunit. Biomolecules 2019; 9:biom9100604. [PMID: 31614896 PMCID: PMC6843408 DOI: 10.3390/biom9100604] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/15/2022] Open
Abstract
The voltage-gated sodium channel is vital for cardiomyocyte function, and consists of a protein complex containing a pore-forming α subunit and two associated β subunits. A fundamental, yet unsolved, question is to define the precise function of β subunits. While their location in vivo remains unclear, large evidence shows that they regulate localization of α and the biophysical properties of the channel. The current data support that one of these subunits, β2, promotes cell surface expression of α. The main α isoform in an adult heart is NaV1.5, and mutations in SCN5A, the gene encoding NaV1.5, often lead to hereditary arrhythmias and sudden death. The association of β2 with cardiac arrhythmias has also been described, which could be due to alterations in trafficking, anchoring, and localization of NaV1.5 at the cardiomyocyte surface. Here, we will discuss research dealing with mechanisms that regulate β2 trafficking, and how β2 could be pivotal for the correct localization of NaV1.5, which influences cellular excitability and electrical coupling of the heart. Moreover, β2 may have yet to be discovered roles on cell adhesion and signaling, implying that diverse defects leading to human disease may arise due to β2 mutations.
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Affiliation(s)
- Eric Cortada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), C/ Doctor Castany, s/n-Edifici IDIBGI, 17190 Girona, Spain.
- Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 28029 Madrid, Spain.
| | - Ramon Brugada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), C/ Doctor Castany, s/n-Edifici IDIBGI, 17190 Girona, Spain.
- Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 28029 Madrid, Spain.
- Medical Sciences Department, University of Girona Medical School, 17003 Girona, Spain.
- Cardiology Department, Hospital Josep Trueta, 17007 Girona, Spain.
| | - Marcel Verges
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), C/ Doctor Castany, s/n-Edifici IDIBGI, 17190 Girona, Spain.
- Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 28029 Madrid, Spain.
- Medical Sciences Department, University of Girona Medical School, 17003 Girona, Spain.
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12
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Haworth AS, Brackenbury WJ. Emerging roles for multifunctional ion channel auxiliary subunits in cancer. Cell Calcium 2019; 80:125-140. [PMID: 31071485 PMCID: PMC6553682 DOI: 10.1016/j.ceca.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.
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Affiliation(s)
- Alexander S Haworth
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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13
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Crystal structures of Ca 2+-calmodulin bound to Na V C-terminal regions suggest role for EF-hand domain in binding and inactivation. Proc Natl Acad Sci U S A 2019; 116:10763-10772. [PMID: 31072926 DOI: 10.1073/pnas.1818618116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium (NaV) and calcium channels (CaV) form targets for calmodulin (CaM), which affects channel inactivation properties. A major interaction site for CaM resides in the C-terminal (CT) region, consisting of an IQ domain downstream of an EF-hand domain. We present a crystal structure of fully Ca2+-occupied CaM, bound to the CT of NaV1.5. The structure shows that the C-terminal lobe binds to a site ∼90° rotated relative to a previous site reported for an apoCaM complex with the NaV1.5 CT and for ternary complexes containing fibroblast growth factor homologous factors (FHF). We show that the binding of FHFs forces the EF-hand domain in a conformation that does not allow binding of the Ca2+-occupied C-lobe of CaM. These observations highlight the central role of the EF-hand domain in modulating the binding mode of CaM. The binding sites for Ca2+-free and Ca2+-occupied CaM contain targets for mutations linked to long-QT syndrome, a type of inherited arrhythmia. The related NaV1.4 channel has been shown to undergo Ca2+-dependent inactivation (CDI) akin to CaVs. We present a crystal structure of Ca2+/CaM bound to the NaV1.4 IQ domain, which shows a binding mode that would clash with the EF-hand domain. We postulate the relative reorientation of the EF-hand domain and the IQ domain as a possible conformational switch that underlies CDI.
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14
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Clairfeuille T, Cloake A, Infield DT, Llongueras JP, Arthur CP, Li ZR, Jian Y, Martin-Eauclaire MF, Bougis PE, Ciferri C, Ahern CA, Bosmans F, Hackos DH, Rohou A, Payandeh J. Structural basis of α-scorpion toxin action on Na v channels. Science 2019; 363:science.aav8573. [PMID: 30733386 DOI: 10.1126/science.aav8573] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023]
Abstract
Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling, but its mechanism remains poorly understood. Here we determined the structures of a eukaryotic Nav channel alone and in complex with a lethal α-scorpion toxin, AaH2, by electron microscopy, both at 3.5-angstrom resolution. AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state in which gating charge interactions bridge to the acidic intracellular carboxyl-terminal domain. In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery. Highlighting the polypharmacology of α-scorpion toxins, AaH2 also targets an unanticipated receptor site on VSD1 and a pore glycan adjacent to VSD4. Overall, this work provides key insights into fast inactivation, electromechanical coupling, and pathogenic mutations in Nav channels.
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Affiliation(s)
- Thomas Clairfeuille
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Alexander Cloake
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.,Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - José P Llongueras
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Zhong Rong Li
- Department of Biomolecular Resources, Genentech Inc., South San Francisco, CA, USA
| | - Yuwen Jian
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, LNC, UMR 7291, 13003 Marseille, France
| | - Claudio Ciferri
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium.
| | - David H Hackos
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
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15
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Huang DL, Bai JS, Wu M, Wang X, Riedl B, Pook E, Alt C, Erny M, Li YM, Bierer D, Shi J, Fang GM. Non-reducible disulfide bond replacement implies that disulfide exchange is not required for hepcidin-ferroportin interaction. Chem Commun (Camb) 2019; 55:2821-2824. [PMID: 30762062 DOI: 10.1039/c9cc00328b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Previous studies have led to opposing hypotheses about the requirement of intermolecular disulfide exchange in the binding of the iron regulatory peptide hepcidin to its receptor ferroportin. To clarify this issue, we used the diaminodiacid approach to replace the disulfide bonds in hepcidin with non-reducible thioether bonds. Our results implied that disulfide exchange is not required for the interaction between hepcidin and ferroportin. This theory is further supported by our development of biologically active minihepcidins that do not show activity dependence on cysteine.
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Affiliation(s)
- Dong-Liang Huang
- School of Life Science, Institute of Health Science and Technology, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China.
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16
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Pan X, Li Z, Huang X, Huang G, Gao S, Shen H, Liu L, Lei J, Yan N. Molecular basis for pore blockade of human Na + channel Na v1.2 by the μ-conotoxin KIIIA. Science 2019; 363:1309-1313. [PMID: 30765605 DOI: 10.1126/science.aaw2999] [Citation(s) in RCA: 167] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/29/2019] [Indexed: 12/16/2022]
Abstract
The voltage-gated sodium channel Nav1.2 is responsible for the initiation and propagation of action potentials in the central nervous system. We report the cryo-electron microscopy structure of human Nav1.2 bound to a peptidic pore blocker, the μ-conotoxin KIIIA, in the presence of an auxiliary subunit, β2, to an overall resolution of 3.0 angstroms. The immunoglobulin domain of β2 interacts with the shoulder of the pore domain through a disulfide bond. The 16-residue KIIIA interacts with the extracellular segments in repeats I to III, placing Lys7 at the entrance to the selectivity filter. Many interacting residues are specific to Nav1.2, revealing a molecular basis for KIIIA specificity. The structure establishes a framework for the rational design of subtype-specific blockers for Nav channels.
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Affiliation(s)
- Xiaojing Pan
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zhangqiang Li
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiaoshuang Huang
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Shuai Gao
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Huaizong Shen
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
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17
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Co-expression of β Subunits with the Voltage-Gated Sodium Channel Na V1.7: the Importance of Subunit Association and Phosphorylation and Their Effects on Channel Pharmacology and Biophysics. J Mol Neurosci 2018; 65:154-166. [PMID: 29744740 DOI: 10.1007/s12031-018-1082-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 05/01/2018] [Indexed: 12/19/2022]
Abstract
The voltage-gated sodium ion channel NaV1.7 is crucial in pain signaling. We examined how auxiliary β2 and β3 subunits and the phosphorylation state of the channel influence its biophysical properties and pharmacology. The human NaV1.7α subunit was co-expressed with either β2 or β3 subunits in HEK-293 cells. The β2 subunits and the NaV1.7α, however, were barely associated as evidenced by immunoprecipitation. Therefore, the β2 subunits did not change the biophysical properties of the channel. In contrast, β3 subunit was clearly associated with NaV1.7α. This subunit had a significant degree of glycosylation, and only the fully glycosylated β3 subunit was associated with the NaV1.7α. Electrophysiological characterisation revealed that the β3 subunit had small but consistent effects: a right-hand shift of the steady-state inactivation and faster recovery from inactivation. Furthermore, the β3 subunit reduced the susceptibility of NaV1.7α to several sodium channel blockers. In addition, we assessed the functional effect of NaV1.7α phosphorylation. Inhibition of kinase activity increased channel inactivation, while the blocking phosphatases produced the opposite effect. In conclusion, co-expression of β subunits with NaV1.7α, to better mimic the native channel properties, may be ineffective in cases when subunits are not associated, as shown in our experiments with β2. The β3 subunit significantly influences the function of NaV1.7α and, together with the phosphorylation of the channel, regulates its biophysical and pharmacological properties. These are important findings to take into account when considering the role of NaV1.7 channel in pain signaling.
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18
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Abstract
Gating pore currents through the voltage-sensing domains (VSDs) of the skeletal muscle voltage-gated sodium channel NaV1.4 underlie hypokalemic periodic paralysis (HypoPP) type 2. Gating modifier toxins target ion channels by modifying the function of the VSDs. We tested the hypothesis that these toxins could function as blockers of the pathogenic gating pore currents. We report that a crab spider toxin Hm-3 from Heriaeus melloteei can inhibit gating pore currents due to mutations affecting the second arginine residue in the S4 helix of VSD-I that we have found in patients with HypoPP and describe here. NMR studies show that Hm-3 partitions into micelles through a hydrophobic cluster formed by aromatic residues and reveal complex formation with VSD-I through electrostatic and hydrophobic interactions with the S3b helix and the S3-S4 extracellular loop. Our data identify VSD-I as a specific binding site for neurotoxins on sodium channels. Gating modifier toxins may constitute useful hits for the treatment of HypoPP.
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19
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Molinarolo S, Lee S, Leisle L, Lueck JD, Granata D, Carnevale V, Ahern CA. Cross-kingdom auxiliary subunit modulation of a voltage-gated sodium channel. J Biol Chem 2018; 293:4981-4992. [PMID: 29371400 PMCID: PMC5892571 DOI: 10.1074/jbc.ra117.000852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/17/2018] [Indexed: 02/04/2023] Open
Abstract
Voltage-gated, sodium ion-selective channels (NaV) generate electrical signals contributing to the upstroke of the action potential in animals. NaVs are also found in bacteria and are members of a larger family of tetrameric voltage-gated channels that includes CaVs, KVs, and NaVs. Prokaryotic NaVs likely emerged from a homotetrameric Ca2+-selective voltage-gated progenerator, and later developed Na+ selectivity independently. The NaV signaling complex in eukaryotes contains auxiliary proteins, termed beta (β) subunits, which are potent modulators of the expression profiles and voltage-gated properties of the NaV pore, but it is unknown whether they can functionally interact with prokaryotic NaV channels. Herein, we report that the eukaryotic NaVβ1-subunit isoform interacts with and enhances the surface expression as well as the voltage-dependent gating properties of the bacterial NaV, NaChBac in Xenopus oocytes. A phylogenetic analysis of the β-subunit gene family proteins confirms that these proteins appeared roughly 420 million years ago and that they have no clear homologues in bacterial phyla. However, a comparison between eukaryotic and bacterial NaV structures highlighted the presence of a conserved fold, which could support interactions with the β-subunit. Our electrophysiological, biochemical, structural, and bioinformatics results suggests that the prerequisites for β-subunit regulation are an evolutionarily stable and intrinsic property of some voltage-gated channels.
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Affiliation(s)
- Steven Molinarolo
- From the Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Sora Lee
- the Weill Cornell Medical College, Cornell University, New York, New York 10065, and
| | - Lilia Leisle
- the Weill Cornell Medical College, Cornell University, New York, New York 10065, and
| | - John D Lueck
- From the Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Daniele Granata
- the Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122
| | - Vincenzo Carnevale
- the Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122
| | - Christopher A Ahern
- From the Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242,
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20
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Gardill BR, Rivera-Acevedo RE, Tung CC, Okon M, McIntosh LP, Van Petegem F. The voltage-gated sodium channel EF-hands form an interaction with the III-IV linker that is disturbed by disease-causing mutations. Sci Rep 2018; 8:4483. [PMID: 29540853 PMCID: PMC5852250 DOI: 10.1038/s41598-018-22713-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/27/2018] [Indexed: 12/20/2022] Open
Abstract
Voltage-gated sodium channels (NaV) are responsible for the rapid depolarization of many excitable cells. They readily inactivate, a process where currents diminish after milliseconds of channel opening. They are also targets for a multitude of disease-causing mutations, many of which have been shown to affect inactivation. A cluster of disease mutations, linked to Long-QT and Brugada syndromes, is located in a C-terminal EF-hand like domain of NaV1.5, the predominant cardiac sodium channel isoform. Previous studies have suggested interactions with the III-IV linker, a cytosolic element directly involved in inactivation. Here we validate and map the interaction interface using isothermal titration calorimetry (ITC) and NMR spectroscopy. We investigated the impact of various disease mutations on the stability of the domain, and found that mutations that cause misfolding of the EF-hand domain result in hyperpolarizing shifts in the steady-state inactivation curve. Conversely, mutations in the III-IV linker that disrupt the interaction with the EF-hand domain also result in large hyperpolarization shifts, supporting the interaction between both elements in intact channels. Disrupting the interaction also causes large late currents, pointing to a dual role of the interaction in reducing the population of channels entering inactivation and in stabilizing the inactivated state.
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Affiliation(s)
- Bernd R Gardill
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Ricardo E Rivera-Acevedo
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Ching-Chieh Tung
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Mark Okon
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Chemistry, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Lawrence P McIntosh
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Chemistry, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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21
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Bang S, Yoo J, Gong X, Liu D, Han Q, Luo X, Chang W, Chen G, Im ST, Kim YH, Strong JA, Zhang MZ, Zhang JM, Lee SY, Ji RR. Differential Inhibition of Nav1.7 and Neuropathic Pain by Hybridoma-Produced and Recombinant Monoclonal Antibodies that Target Nav1.7 : Differential activities of Nav1.7-targeting monoclonal antibodies. Neurosci Bull 2018; 34:22-41. [PMID: 29333591 PMCID: PMC5799132 DOI: 10.1007/s12264-018-0203-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 12/18/2017] [Indexed: 12/21/2022] Open
Abstract
The voltage-gated Na+ channel subtype Nav1.7 is important for pain and itch in rodents and humans. We previously showed that a Nav1.7-targeting monoclonal antibody (SVmab) reduces Na+ currents and pain and itch responses in mice. Here, we investigated whether recombinant SVmab (rSVmab) binds to and blocks Nav1.7 similar to SVmab. ELISA tests revealed that SVmab was capable of binding to Nav1.7-expressing HEK293 cells, mouse DRG neurons, human nerve tissue, and the voltage-sensor domain II of Nav1.7. In contrast, rSVmab showed no or weak binding to Nav1.7 in these tests. Patch-clamp recordings showed that SVmab, but not rSVmab, markedly inhibited Na+ currents in Nav1.7-expressing HEK293 cells. Notably, electrical field stimulation increased the blocking activity of SVmab and rSVmab in Nav1.7-expressing HEK293 cells. SVmab was more effective than rSVmab in inhibiting paclitaxel-induced mechanical allodynia. SVmab also bound to human DRG neurons and inhibited their Na+ currents. Finally, potential reasons for the differential efficacy of SVmab and rSVmab and future directions are discussed.
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Affiliation(s)
- Sangsu Bang
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
| | - Jiho Yoo
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, NC, 27710, USA
| | - Xingrui Gong
- Pain Research Center, Department of Anesthesiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA
- Department of Anesthesiology, Shanghai Children's Medical Center, Shanghai, 200127, China
| | - Di Liu
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
| | - Qingjian Han
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
| | - Xin Luo
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
| | - Wonseok Chang
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
- Department of Physiology and Biophysics, College of Medicine, Eulji University, 143-5 Yongdu-Dong, Jung-Gu, Daejeon, 34824, Korea
| | - Gang Chen
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
| | - Sang-Taek Im
- Department of Physiology, College of Medicine, Gachon University, Incheon, 21999, Korea
| | - Yong Ho Kim
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA
- Department of Physiology, College of Medicine, Gachon University, Incheon, 21999, Korea
| | - Judith A Strong
- Pain Research Center, Department of Anesthesiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA
| | - Ma-Zhong Zhang
- Department of Anesthesiology, Shanghai Children's Medical Center, Shanghai, 200127, China
| | - Jun-Ming Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA.
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, NC, 27710, USA.
| | - Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, 595 LaSalle St, Durham, NC, 27710, USA.
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22
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Mangold KE, Brumback BD, Angsutararux P, Voelker TL, Zhu W, Kang PW, Moreno JD, Silva JR. Mechanisms and models of cardiac sodium channel inactivation. Channels (Austin) 2017; 11:517-533. [PMID: 28837385 PMCID: PMC5786193 DOI: 10.1080/19336950.2017.1369637] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/14/2017] [Accepted: 08/15/2017] [Indexed: 12/19/2022] Open
Abstract
Shortly after cardiac Na+ channels activate and initiate the action potential, inactivation ensues within milliseconds, attenuating the peak Na+ current, INa, and allowing the cell membrane to repolarize. A very limited number of Na+ channels that do not inactivate carry a persistent INa, or late INa. While late INa is only a small fraction of peak magnitude, it significantly prolongs ventricular action potential duration, which predisposes patients to arrhythmia. Here, we review our current understanding of inactivation mechanisms, their regulation, and how they have been modeled computationally. Based on this body of work, we conclude that inactivation and its connection to late INa would be best modeled with a "feet-on-the-door" approach where multiple channel components participate in determining inactivation and late INa. This model reflects experimental findings showing that perturbation of many channel locations can destabilize inactivation and cause pathological late INa.
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Affiliation(s)
- Kathryn E. Mangold
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Brittany D. Brumback
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Taylor L. Voelker
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Wandi Zhu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Po Wei Kang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jonathan D. Moreno
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jonathan R. Silva
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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23
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Hull JM, Isom LL. Voltage-gated sodium channel β subunits: The power outside the pore in brain development and disease. Neuropharmacology 2017; 132:43-57. [PMID: 28927993 DOI: 10.1016/j.neuropharm.2017.09.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/19/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022]
Abstract
Voltage gated sodium channels (VGSCs) were first identified in terms of their role in the upstroke of the action potential. The underlying proteins were later identified as saxitoxin and scorpion toxin receptors consisting of α and β subunits. We now know that VGSCs are heterotrimeric complexes consisting of a single pore forming α subunit joined by two β subunits; a noncovalently linked β1 or β3 and a covalently linked β2 or β4 subunit. VGSC α subunits contain all the machinery necessary for channel cell surface expression, ion conduction, voltage sensing, gating, and inactivation, in one central, polytopic, transmembrane protein. VGSC β subunits are more than simple accessories to α subunits. In the more than two decades since the original cloning of β1, our knowledge of their roles in physiology and pathophysiology has expanded immensely. VGSC β subunits are multifunctional. They confer unique gating mechanisms, regulate cellular excitability, affect brain development, confer distinct channel pharmacology, and have functions that are independent of the α subunits. The vast array of functions of these proteins stems from their special station in the channelome: being the only known constituents that are cell adhesion and intra/extracellular signaling molecules in addition to being part of channel complexes. This functional trifecta and how it goes awry demonstrates the power outside the pore in ion channel signaling complexes, broadening the term channelopathy beyond defects in ion conduction. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Jacob M Hull
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lori L Isom
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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24
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Zhu W, Voelker TL, Varga Z, Schubert AR, Nerbonne JM, Silva JR. Mechanisms of noncovalent β subunit regulation of Na V channel gating. J Gen Physiol 2017; 149:813-831. [PMID: 28720590 PMCID: PMC5560778 DOI: 10.1085/jgp.201711802] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/26/2017] [Indexed: 11/20/2022] Open
Abstract
Voltage-gated NaV channels are modulated by two different noncovalent accessory subunits: β1 and β3. Zhu et al. present data showing that β1 and β3 cause distinct effects on channel gating because they interact with NaV channels at different locations. β3 regulates the voltage sensor in domain III, whereas β1 regulates the one in domain IV. Voltage-gated Na+ (NaV) channels comprise a macromolecular complex whose components tailor channel function. Key components are the non-covalently bound β1 and β3 subunits that regulate channel gating, expression, and pharmacology. Here, we probe the molecular basis of this regulation by applying voltage clamp fluorometry to measure how the β subunits affect the conformational dynamics of the cardiac NaV channel (NaV1.5) voltage-sensing domains (VSDs). The pore-forming NaV1.5 α subunit contains four domains (DI–DIV), each with a VSD. Our results show that β1 regulates NaV1.5 by modulating the DIV-VSD, whereas β3 alters channel kinetics mainly through DIII-VSD interaction. Introduction of a quenching tryptophan into the extracellular region of the β3 transmembrane segment inverted the DIII-VSD fluorescence. Additionally, a fluorophore tethered to β3 at the same position produced voltage-dependent fluorescence dynamics strongly resembling those of the DIII-VSD. Together, these results provide compelling evidence that β3 binds proximally to the DIII-VSD. Molecular-level differences in β1 and β3 interaction with the α subunit lead to distinct activation and inactivation recovery kinetics, significantly affecting NaV channel regulation of cell excitability.
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Affiliation(s)
- Wandi Zhu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
| | - Taylor L Voelker
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
| | - Zoltan Varga
- MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Debrecen, Hungary
| | - Angela R Schubert
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO.,Department of Internal Medicine, Washington University in St. Louis, St. Louis, MO
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO
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25
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Yan Z, Zhou Q, Wang L, Wu J, Zhao Y, Huang G, Peng W, Shen H, Lei J, Yan N. Structure of the Na v1.4-β1 Complex from Electric Eel. Cell 2017; 170:470-482.e11. [PMID: 28735751 DOI: 10.1016/j.cell.2017.06.039] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/26/2017] [Accepted: 06/23/2017] [Indexed: 02/07/2023]
Abstract
Voltage-gated sodium (Nav) channels initiate and propagate action potentials. Here, we present the cryo-EM structure of EeNav1.4, the Nav channel from electric eel, in complex with the β1 subunit at 4.0 Å resolution. The immunoglobulin domain of β1 docks onto the extracellular L5I and L6IV loops of EeNav1.4 via extensive polar interactions, and the single transmembrane helix interacts with the third voltage-sensing domain (VSDIII). The VSDs exhibit "up" conformations, while the intracellular gate of the pore domain is kept open by a digitonin-like molecule. Structural comparison with closed NavPaS shows that the outward transfer of gating charges is coupled to the iris-like pore domain dilation through intricate force transmissions involving multiple channel segments. The IFM fast inactivation motif on the III-IV linker is plugged into the corner enclosed by the outer S4-S5 and inner S6 segments in repeats III and IV, suggesting a potential allosteric blocking mechanism for fast inactivation.
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Affiliation(s)
- Zhen Yan
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lin Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianping Wu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanyu Zhao
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Gaoxingyu Huang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Peng
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huaizong Shen
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China; Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
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26
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Shimizu H, Tosaki A, Ohsawa N, Ishizuka-Katsura Y, Shoji S, Miyazaki H, Oyama F, Terada T, Shirouzu M, Sekine SI, Nukina N, Yokoyama S. Parallel homodimer structures of the extracellular domains of the voltage-gated sodium channel β4 subunit explain its role in cell-cell adhesion. J Biol Chem 2017; 292:13428-13440. [PMID: 28655765 PMCID: PMC5555201 DOI: 10.1074/jbc.m117.786509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/26/2017] [Indexed: 11/06/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are transmembrane proteins required for the generation of action potentials in excitable cells and essential for propagating electrical impulses along nerve cells. VGSCs are complexes of a pore-forming α subunit and auxiliary β subunits, designated as β1/β1B-β4 (encoded by SCN1B-4B, respectively), which also function in cell-cell adhesion. We previously reported the structural basis for the trans homophilic interaction of the β4 subunit, which contributes to its adhesive function. Here, using crystallographic and biochemical analyses, we show that the β4 extracellular domains directly interact with each other in a parallel manner that involves an intermolecular disulfide bond between the unpaired Cys residues (Cys58) in the loop connecting strands B and C and intermolecular hydrophobic and hydrogen-bonding interactions of the N-terminal segments (Ser30-Val35). Under reducing conditions, an N-terminally deleted β4 mutant exhibited decreased cell adhesion compared with the wild type, indicating that the β4 cis dimer contributes to the trans homophilic interaction of β4 in cell-cell adhesion. Furthermore, this mutant exhibited increased association with the α subunit, indicating that the cis dimerization of β4 affects α-β4 complex formation. These observations provide the structural basis for the parallel dimer formation of β4 in VGSCs and reveal its mechanism in cell-cell adhesion.
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Affiliation(s)
- Hideaki Shimizu
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan.,the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Asako Tosaki
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Noboru Ohsawa
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Yoshiko Ishizuka-Katsura
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shisako Shoji
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Haruko Miyazaki
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,the Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Fumitaka Oyama
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Chemistry and Life Science, Kogakuin University, Hachioji, Tokyo 192-0015, Japan, and
| | - Takaho Terada
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
| | - Mikako Shirouzu
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shun-Ichi Sekine
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Nobuyuki Nukina
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,the Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Shigeyuki Yokoyama
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan, .,the RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
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27
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Wingerd JS, Mozar CA, Ussing CA, Murali SS, Chin YKY, Cristofori-Armstrong B, Durek T, Gilchrist J, Vaughan CW, Bosmans F, Adams DJ, Lewis RJ, Alewood PF, Mobli M, Christie MJ, Rash LD. The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity. Sci Rep 2017; 7:974. [PMID: 28428547 PMCID: PMC5430537 DOI: 10.1038/s41598-017-01129-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/27/2017] [Indexed: 11/09/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are essential for the transmission of pain signals in humans making them prime targets for the development of new analgesics. Spider venoms are a rich source of peptide modulators useful to study ion channel structure and function. Here we describe β/δ-TRTX-Pre1a, a 35-residue tarantula peptide that selectively interacts with neuronal NaV channels inhibiting peak current of hNaV1.1, rNaV1.2, hNaV1.6, and hNaV1.7 while concurrently inhibiting fast inactivation of hNaV1.1 and rNaV1.3. The DII and DIV S3-S4 loops of NaV channel voltage sensors are important for the interaction of Pre1a with NaV channels but cannot account for its unique subtype selectivity. Through analysis of the binding regions we ascertained that the variability of the S1-S2 loops between NaV channels contributes substantially to the selectivity profile observed for Pre1a, particularly with regards to fast inactivation. A serine residue on the DIV S2 helix was found to be sufficient to explain Pre1a’s potent and selective inhibitory effect on the fast inactivation process of NaV1.1 and 1.3. This work highlights that interactions with both S1-S2 and S3-S4 of NaV channels may be necessary for functional modulation, and that targeting the diverse S1-S2 region within voltage-sensing domains provides an avenue to develop subtype selective tools.
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Affiliation(s)
- Joshua S Wingerd
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Christine A Mozar
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Christine A Ussing
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.,Novo Nordisk A/S, Copenhagen Area, Capital Region, Denmark
| | - Swetha S Murali
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia.,Harvard Medical School, Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, United States
| | - Yanni K-Y Chin
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - John Gilchrist
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Christopher W Vaughan
- Pain Management Research Institute, University of Sydney, St Leonards, NSW, 2006, Australia
| | - Frank Bosmans
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging & School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Macdonald J Christie
- Discipline of Pharmacology, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia. .,School of Biomedical Sciences, The University of Queensland, St Lucia, 4072, QLD, Australia.
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28
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Shen H, Zhou Q, Pan X, Li Z, Wu J, Yan N. Structure of a eukaryotic voltage-gated sodium channel at near-atomic resolution. Science 2017; 355:science.aal4326. [PMID: 28183995 DOI: 10.1126/science.aal4326] [Citation(s) in RCA: 283] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/31/2017] [Indexed: 01/09/2023]
Abstract
Voltage-gated sodium (Nav) channels are responsible for the initiation and propagation of action potentials. They are associated with a variety of channelopathies and are targeted by multiple pharmaceutical drugs and natural toxins. Here, we report the cryogenic electron microscopy structure of a putative Nav channel from American cockroach (designated NavPaS) at 3.8 angstrom resolution. The voltage-sensing domains (VSDs) of the four repeats exhibit distinct conformations. The entrance to the asymmetric selectivity filter vestibule is guarded by heavily glycosylated and disulfide bond-stabilized extracellular loops. On the cytoplasmic side, a conserved amino-terminal domain is placed below VSDI, and a carboxy-terminal domain binds to the III-IV linker. The structure of NavPaS establishes an important foundation for understanding function and disease mechanism of Nav and related voltage-gated calcium channels.
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Affiliation(s)
- Huaizong Shen
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Zhangqiang Li
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Jianping Wu
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
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29
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Molinarolo S, Granata D, Carnevale V, Ahern CA. Mining Protein Evolution for Insights into Mechanisms of Voltage-Dependent Sodium Channel Auxiliary Subunits. Handb Exp Pharmacol 2017; 246:33-49. [PMID: 29464397 DOI: 10.1007/164_2017_75] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Voltage-gated sodium channel (VGSC) beta (β) subunits have been called the "overachieving" auxiliary ion channel subunit. Indeed, these subunits regulate the trafficking of the sodium channel complex at the plasma membrane and simultaneously tune the voltage-dependent properties of the pore-forming alpha-subunit. It is now known that VGSC β-subunits are capable of similar modulation of multiple isoforms of related voltage-gated potassium channels, suggesting that their abilities extend into the broader voltage-gated channels. The gene family for these single transmembrane immunoglobulin beta-fold proteins extends well beyond the traditional VGSC β1-β4 subunit designation, with deep roots into the cell adhesion protein family and myelin-related proteins - where inherited mutations result in a myriad of electrical signaling disorders. Yet, very little is known about how VGSC β-subunits support protein trafficking pathways, the basis for their modulation of voltage-dependent gating, and, ultimately, their role in shaping neuronal excitability. An evolutionary approach can be useful in yielding new clues to such functions as it provides an unbiased assessment of protein residues, folds, and functions. An approach is described here which indicates the greater emergence of the modern β-subunits roughly 400 million years ago in the early neurons of Bilateria and bony fish, and the unexpected presence of distant homologues in bacteriophages. Recent structural breakthroughs containing α and β eukaryotic sodium channels containing subunits suggest a novel role for a highly conserved polar contact that occurs within the transmembrane segments. Overall, a mixture of approaches will ultimately advance our understanding of the mechanism for β-subunit interactions with voltage-sensor containing ion channels and membrane proteins.
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Affiliation(s)
- Steven Molinarolo
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Daniele Granata
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA, USA
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA, USA.
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
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30
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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31
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Liu D, Tseng M, Epstein LF, Green L, Chan B, Soriano B, Lim D, Pan O, Murawsky CM, King CT, Moyer BD. Evaluation of recombinant monoclonal antibody SVmab1 binding to Na V1.7 target sequences and block of human Na V1.7 currents. F1000Res 2016; 5:2764. [PMID: 27990272 PMCID: PMC5155501 DOI: 10.12688/f1000research.9918.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/11/2016] [Indexed: 01/16/2023] Open
Abstract
Identification of small and large molecule pain therapeutics that target the genetically validated voltage-gated sodium channel Na
V1.7 is a challenging endeavor under vigorous pursuit. The monoclonal antibody SVmab1 was recently published to bind the Na
V1.7 DII voltage sensor domain and block human Na
V1.7 sodium currents in heterologous cells. We produced purified SVmab1 protein based on publically available sequence information, and evaluated its activity in a battery of binding and functional assays. Herein, we report that our recombinant SVmAb1 does not bind peptide immunogen or purified Na
V1.7 DII voltage sensor domain via ELISA, and does not bind Na
V1.7 in live HEK293, U-2 OS, and CHO-K1 cells via FACS. Whole cell manual patch clamp electrophysiology protocols interrogating diverse Na
V1.7 gating states in HEK293 cells, revealed that recombinant SVmab1 does not block Na
V1.7 currents to an extent greater than observed with an isotype matched control antibody. Collectively, our results show that recombinant SVmab1 monoclonal antibody does not bind Na
V1.7 target sequences or specifically inhibit Na
V1.7 current.
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Affiliation(s)
- Dong Liu
- Neuroscience, Amgen Inc., Thousand Oaks, USA
| | | | | | | | | | - Brian Soriano
- Discovery Attribute Sciences, Amgen Inc., Thousand Oaks, USA
| | | | - Oscar Pan
- Amgen British Columbia, Burnaby, Canada
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32
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Green BR, Olivera BM. Venom Peptides From Cone Snails: Pharmacological Probes for Voltage-Gated Sodium Channels. CURRENT TOPICS IN MEMBRANES 2016; 78:65-86. [PMID: 27586281 DOI: 10.1016/bs.ctm.2016.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The venoms of cone snails provide a rich source of neuroactive peptides (conotoxins). Several venom peptide families have been identified that are either agonists (ι- and δ-conotoxins) or antagonists (μ- and μO-conotoxins) of voltage-gated sodium channels (VGSCs). Members of these conotoxin classes have been integral in identifying and characterizing specific neurotoxin binding sites on the channel. Furthermore, given the specificity of some of these peptides for one sodium channel subtype over another, conotoxins have also proven useful in exploring differences between VGSC subtypes. This chapter summarizes the current knowledge of the structure and function based on the results of conotoxin interactions with VGSCs and correlates the peptides with the phylogeny of the Conus species from which they were derived.
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Affiliation(s)
- B R Green
- University of Utah, Salt Lake City, UT, United States; Monash University, Parkville, VIC, Australia
| | - B M Olivera
- University of Utah, Salt Lake City, UT, United States
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33
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Shimizu H, Miyazaki H, Ohsawa N, Shoji S, Ishizuka-Katsura Y, Tosaki A, Oyama F, Terada T, Sakamoto K, Shirouzu M, Sekine SI, Nukina N, Yokoyama S. Structure-based site-directed photo-crosslinking analyses of multimeric cell-adhesive interactions of voltage-gated sodium channel β subunits. Sci Rep 2016; 6:26618. [PMID: 27216889 PMCID: PMC4877568 DOI: 10.1038/srep26618] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 05/04/2016] [Indexed: 11/09/2022] Open
Abstract
The β1, β2, and β4 subunits of voltage-gated sodium channels reportedly function as cell adhesion molecules. The present crystallographic analysis of the β4 extracellular domain revealed an antiparallel arrangement of the β4 molecules in the crystal lattice. The interface between the two antiparallel β4 molecules is asymmetric, and results in a multimeric assembly. Structure-based mutagenesis and site-directed photo-crosslinking analyses of the β4-mediated cell-cell adhesion revealed that the interface between the antiparallel β4 molecules corresponds to that in the trans homophilic interaction for the multimeric assembly of β4 in cell-cell adhesion. This trans interaction mode is also employed in the β1-mediated cell-cell adhesion. Moreover, the β1 gene mutations associated with generalized epilepsy with febrile seizures plus (GEFS+) impaired the β1-mediated cell-cell adhesion, which should underlie the GEFS+ pathogenesis. Thus, the structural basis for the β-subunit-mediated cell-cell adhesion has been established.
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Affiliation(s)
- Hideaki Shimizu
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan.,Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Haruko Miyazaki
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Noboru Ohsawa
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shisako Shoji
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Yoshiko Ishizuka-Katsura
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Asako Tosaki
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Fumitaka Oyama
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Department of Chemistry and Life Science, Kogakuin University, Hachioji, Tokyo 192-0015, Japan
| | - Takaho Terada
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
| | - Kensaku Sakamoto
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Mikako Shirouzu
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shun-Ichi Sekine
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Nobuyuki Nukina
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Shigeyuki Yokoyama
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
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