1
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Molton O, Bignucolo O, Kellenberger S. Identification of the modulatory Ca 2+-binding sites of acid-sensing ion channel 1a. Open Biol 2024; 14:240028. [PMID: 38896086 DOI: 10.1098/rsob.240028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/28/2024] [Indexed: 06/21/2024] Open
Abstract
Acid-sensing ion channels (ASICs) are neuronal Na+-permeable ion channels activated by extracellular acidification. ASICs are involved in learning, fear sensing, pain sensation and neurodegeneration. Increasing the extracellular Ca2+ concentration decreases the H+ sensitivity of ASIC1a, suggesting a competition for binding sites between H+ and Ca2+ ions. Here, we predicted candidate residues for Ca2+ binding on ASIC1a, based on available structural information and our molecular dynamics simulations. With functional measurements, we identified several residues in cavities previously associated with pH-dependent gating, whose mutation reduced the modulation by extracellular Ca2+ of the ASIC1a pH dependence of activation and desensitization. This occurred likely owing to a disruption of Ca2+ binding. Our results link one of the two predicted Ca2+-binding sites in each ASIC1a acidic pocket to the modulation of channel activation. Mg2+ regulates ASICs in a similar way as does Ca2+. We show that Mg2+ shares some of the binding sites with Ca2+. Finally, we provide evidence that some of the ASIC1a Ca2+-binding sites are functionally conserved in the splice variant ASIC1b. Our identification of divalent cation-binding sites in ASIC1a shows how Ca2+ affects ASIC1a gating, elucidating a regulatory mechanism present in many ion channels.
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Affiliation(s)
- Ophélie Molton
- Department of Biomedical Sciences, University of Lausanne , 1011 Lausanne, Switzerland
| | | | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne , 1011 Lausanne, Switzerland
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2
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Sarkar D, Galleano I, Heusser SA, Ou SY, Uzun GR, Khoo KK, van der Heden van Noort GJ, Harrison JS, Pless SA. Protein semisynthesis underscores the role of a conserved lysine in activation and desensitization of acid-sensing ion channels. Cell Chem Biol 2024; 31:1000-1010.e6. [PMID: 38113885 DOI: 10.1016/j.chembiol.2023.11.013] [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: 01/24/2023] [Revised: 07/21/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023]
Abstract
Acid-sensing ion channels (ASICs) are trimeric ion channels that open a cation-conducting pore in response to proton binding. Excessive ASIC activation during prolonged acidosis in conditions such as inflammation and ischemia is linked to pain and stroke. A conserved lysine in the extracellular domain (Lys211 in mASIC1a) is suggested to play a key role in ASIC function. However, the precise contributions are difficult to dissect with conventional mutagenesis, as replacement of Lys211 with naturally occurring amino acids invariably changes multiple physico-chemical parameters. Here, we study the contribution of Lys211 to mASIC1a function using tandem protein trans-splicing (tPTS) to incorporate non-canonical lysine analogs. We conduct optimization efforts to improve splicing and functionally interrogate semisynthetic mASIC1a. In combination with molecular modeling, we show that Lys211 charge and side-chain length are crucial to activation and desensitization, thus emphasizing that tPTS can enable atomic-scale interrogations of membrane proteins in live cells.
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Affiliation(s)
- Debayan Sarkar
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Iacopo Galleano
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, the Netherlands
| | | | - Sofie Yuewei Ou
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Gül Refika Uzun
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Keith K Khoo
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | | | - Stephan Alexander Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark.
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3
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Purohit R, Couch T, MacLean DM. Proline substitutions in the ASIC1 β11-12 linker slow desensitization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593312. [PMID: 38798386 PMCID: PMC11118455 DOI: 10.1101/2024.05.09.593312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Desensitization is a prominent feature of nearly all ligand gated ion channels. Acid-sensing ion channels (ASIC) undergo desensitization within hundreds of milliseconds to seconds upon continual extracellular acidification. The ASIC mechanism of desensitization is primarily due to the isomerization or "flipping" of a short linker joining the 11th and 12th beta sheets in the extracellular domain. In the resting and active states this β11-12 linker adopts an "upward" conformation while in the desensitized conformation the linker assumes a "downward" state. To accommodate this "downward" state, specific peptide bonds within the linker adopt either trans-like or cis-like conformations. Since proline-containing peptide bonds undergo cis-trans isomerization very slowly, we hypothesized that introducing proline residues in the linker may slow or even abolish ASIC desensitization, potentially providing a valuable research tools. Proline substitutions in the chicken ASIC1 β11-12 linker (L414P and Y416P) slowed desensitization decays approximately 100 to 1000-fold as measured in excised patches. Both L414P and Y416P shifted the steady state desensitization curves to more acidic pHs while activation curves and ion selectivity of these slow-desensitizing currents were largely unaffected. To investigate the functional stoichiometry of desensitization in the trimeric ASIC, we created families of L414P and Y416P concatemers with zero, one, two or three proline substitutions in all possible configurations. Introducing one or two L414P or Y416P mutations only slightly attenuated desensitization, suggesting that conformational changes in the remaining faster wild type subunits were sufficient to desensitize the channel. These data highlight the unusual cis-trans isomerization mechanism of ASIC desensitization and support a model where a single subunit is sufficient to desensitize the entire channel.
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Affiliation(s)
- Rutambhara Purohit
- Department of Pharmacology and Physiology, University of Rochester Medical Center
| | - Tyler Couch
- Department of Pharmacology and Physiology, University of Rochester Medical Center
| | - David M MacLean
- Department of Pharmacology and Physiology, University of Rochester Medical Center
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4
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Lu Y, Lin Y, Wang J. Progress on functions of intracellular domain of trimeric ligand-gated ion channels. Zhejiang Da Xue Xue Bao Yi Xue Ban 2024; 53:221-230. [PMID: 38310082 PMCID: PMC11057991 DOI: 10.3724/zdxbyxb-2023-0472] [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: 09/30/2023] [Accepted: 11/11/2023] [Indexed: 02/05/2024]
Abstract
Ligand-gated ion channels are a large category of essential ion channels, modulating their state by binding to specific ligands to allow ions to pass through the cell membrane. Purinergic ligand-gated ion channel receptors (P2XRs) and acid-sensitive ion channels (ASICs) are representative members of trimeric ligand-gated ion channel. Recent studies have shown that structural differences in the intracellular domain of P2XRs may determine the desensitization process. The lateral fenestrations of P2XRs potentially serve as a pathway for ion conductance and play a decisive role in ion selectivity. Phosphorylation of numerous amino acid residues in the P2XRs are involved in regulating the activity of ion channels. Additionally, the P2XRs interact with other ligand-gated ion channels including N-methyl-D-aspartate receptors, γ-aminobutyric acid receptors, 5-hydroxytryptamin receptors and nicotinic acetylcholine receptors, mediating physiological processes such as synaptic plasticity. Conformational changes in the intracellular domain of the ASICs expose binding sites of intracellular signal partners, facilitating metabolic signal transduction. Amino acids such as Val16, Ser17, Ile18, Gln19 and Ala20 in the ASICs participate in channel opening and membrane expression. ASICs can also bind to intracellular proteins, such as CIPP and p11, to regulate channel function. Many phosphorylation sites at the C-terminus and N-terminus of ASICs are involved in the regulation of receptors. Furthermore, ASICs are involved in various physiological and pathophysiological processes, which include pain, ischemic stroke, psychiatric disorders, and neurodegenerative disease. In this article, we review the roles of the intracellular domains of these trimeric ligand-gated ion channels in channel gating as well as their physiological and pathological functions, in order to provide new insights into the discovery of related drugs.
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Affiliation(s)
- Yan Lu
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| | - Yiyu Lin
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Jin Wang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
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5
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Sure F, Einsiedel J, Gmeiner P, Duchstein P, Zahn D, Korbmacher C, Ilyaskin AV. The small molecule activator S3969 stimulates the epithelial sodium channel by interacting with a specific binding pocket in the channel's β-subunit. J Biol Chem 2024; 300:105785. [PMID: 38401845 PMCID: PMC11065748 DOI: 10.1016/j.jbc.2024.105785] [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: 09/25/2023] [Revised: 01/13/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024] Open
Abstract
The epithelial sodium channel (ENaC) is essential for mediating sodium absorption in several epithelia. Its impaired function leads to severe disorders, including pseudohypoaldosteronism type 1 and respiratory distress. Therefore, pharmacological ENaC activators have potential therapeutic implications. Previously, a small molecule ENaC activator (S3969) was developed. So far, little is known about molecular mechanisms involved in S3969-mediated ENaC stimulation. Here, we identified an S3969-binding site in human ENaC by combining structure-based simulations with molecular biological methods and electrophysiological measurements of ENaC heterologously expressed in Xenopus laevis oocytes. We confirmed a previous observation that the extracellular loop of β-ENaC is essential for ENaC stimulation by S3969. Molecular dynamics simulations predicted critical residues in the thumb domain of β-ENaC (Arg388, Phe391, and Tyr406) that coordinate S3969 within a binding site localized at the β-γ-subunit interface. Importantly, mutating each of these residues reduced (R388H; R388A) or nearly abolished (F391G; Y406A) the S3969-mediated ENaC activation. Molecular dynamics simulations also suggested that S3969-mediated ENaC stimulation involved a movement of the α5 helix of the thumb domain of β-ENaC away from the palm domain of γ-ENaC. Consistent with this, the introduction of two cysteine residues (βR437C - γS298C) to form a disulfide bridge connecting these two domains prevented ENaC stimulation by S3969 unless the disulfide bond was reduced by DTT. Finally, we demonstrated that S3969 stimulated ENaC endogenously expressed in cultured human airway epithelial cells (H441). These new findings may lead to novel (patho-)physiological and therapeutic concepts for disorders associated with altered ENaC function.
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Affiliation(s)
- Florian Sure
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jürgen Einsiedel
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Patrick Duchstein
- Theoretical Chemistry/Computer Chemistry Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Dirk Zahn
- Theoretical Chemistry/Computer Chemistry Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Christoph Korbmacher
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Alexandr V Ilyaskin
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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6
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Kalienkova V, Dandamudi M, Paulino C, Lynagh T. Structural basis for excitatory neuropeptide signaling. Nat Struct Mol Biol 2024; 31:717-726. [PMID: 38337033 PMCID: PMC11026163 DOI: 10.1038/s41594-023-01198-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 12/05/2023] [Indexed: 02/12/2024]
Abstract
Rapid signaling between neurons is mediated by ligand-gated ion channels, cell-surface proteins with an extracellular ligand-binding domain and a membrane-spanning ion channel domain. The degenerin/epithelial sodium channel (DEG/ENaC) superfamily is diverse in terms of its gating stimuli, with some DEG/ENaCs gated by neuropeptides, and others gated by pH, mechanical force or enzymatic activity. The mechanism by which ligands bind to and activate DEG/ENaCs is poorly understood. Here we dissected the structural basis for neuropeptide-gated activity of a neuropeptide-gated DEG/ENaC, FMRFamide-gated sodium channel 1 (FaNaC1) from the annelid worm Malacoceros fuliginosus, using cryo-electron microscopy. Structures of FaNaC1 in the ligand-free resting state and in several ligand-bound states reveal the ligand-binding site and capture the ligand-induced conformational changes of channel gating, which we verified with complementary mutagenesis experiments. Our results illuminate channel gating in DEG/ENaCs and offer a structural template for experimental dissection of channel pharmacology and ion conduction.
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Affiliation(s)
- Valeria Kalienkova
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Cristina Paulino
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
- Biochemistry Center, Heidelberg University, Heidelberg, Germany.
| | - Timothy Lynagh
- Michael Sars Centre, University of Bergen, Bergen, Norway.
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7
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Holm CM, Topaktas AB, Dannesboe J, Pless SA, Heusser SA. Dynamic conformational changes of acid-sensing ion channels in different desensitizing conditions. Biophys J 2024:S0006-3495(24)00240-6. [PMID: 38549370 DOI: 10.1016/j.bpj.2024.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/21/2024] [Accepted: 03/26/2024] [Indexed: 04/18/2024] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated cation channels that contribute to fast synaptic transmission and have roles in fear conditioning and nociception. Apart from activation at low pH, ASIC1a also undergoes several types of desensitization, including acute desensitization, which terminates activation; steady-state desensitization, which occurs at sub-activating proton concentrations and limits subsequent activation; and tachyphylaxis, which results in a progressive decrease in response during a series of activations. Structural insights from a desensitized state of ASIC1 have provided great spatial detail, but dynamic insights into conformational changes in different desensitizing conditions are largely missing. Here, we use electrophysiology and voltage-clamp fluorometry to follow the functional changes of the pore along with conformational changes at several positions in the extracellular and upper transmembrane domain via cysteine-labeled fluorophores. Acute desensitization terminates activation in wild type, but introducing an N414K mutation in the β11-12 linker of mouse ASIC1a interfered with this process. The mutation also affected steady-state desensitization and led to pronounced tachyphylaxis. Although the extracellular domain of this mutant remained sensitive to pH and underwent pH-dependent conformational changes, these conformational changes did not necessarily lead to desensitization. N414K-containing channels also remained sensitive to a known peptide modulator that increases steady-state desensitization, indicating that the mutation only reduced, but not precluded, desensitization. Together, this study contributes to our understanding of the fundamental properties of ASIC1a desensitization, emphasizing the complex interplay between the conformational changes of the extracellular domain and the pore during channel activation and desensitization.
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Affiliation(s)
- Caroline Marcher Holm
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Asli B Topaktas
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Johs Dannesboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stephan A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Stephanie A Heusser
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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8
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Platonov M, Maximyuk O, Rayevsky A, Hurmach V, Iegorova O, Naumchyk V, Bulgakov E, Cherninskyi A, Ozheredov D, Ryabukhin SV, Krishtal O, Volochnyuk DM. 4-(Azolyl)-Benzamidines as a Novel Chemotype for ASIC1a Inhibitors. Int J Mol Sci 2024; 25:3584. [PMID: 38612396 PMCID: PMC11011685 DOI: 10.3390/ijms25073584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/03/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024] Open
Abstract
Acid-sensing ion channels (ASICs) play a key role in the perception and response to extracellular acidification changes. These proton-gated cation channels are critical for neuronal functions, like learning and memory, fear, mechanosensation and internal adjustments like synaptic plasticity. Moreover, they play a key role in neuronal degeneration, ischemic neuronal injury, seizure termination, pain-sensing, etc. Functional ASICs are homo or heterotrimers formed with (ASIC1-ASIC3) homologous subunits. ASIC1a, a major ASIC isoform in the central nervous system (CNS), possesses an acidic pocket in the extracellular region, which is a key regulator of channel gating. Growing data suggest that ASIC1a channels are a potential therapeutic target for treating a variety of neurological disorders, including stroke, epilepsy and pain. Many studies were aimed at identifying allosteric modulators of ASIC channels. However, the regulation of ASICs remains poorly understood. Using all available crystal structures, which correspond to different functional states of ASIC1, and a molecular dynamics simulation (MD) protocol, we analyzed the process of channel inactivation. Then we applied a molecular docking procedure to predict the protein conformation suitable for the amiloride binding. To confirm the effect of its sole active blocker against the ASIC1 state transition route we studied the complex with another MD simulation run. Further experiments evaluated various compounds in the Enamine library that emerge with a detectable ASIC inhibitory activity. We performed a detailed analysis of the structural basis of ASIC1a inhibition by amiloride, using a combination of in silico approaches to visualize its interaction with the ion pore in the open state. An artificial activation (otherwise, expansion of the central pore) causes a complex modification of the channel structure, namely its transmembrane domain. The output protein conformations were used as a set of docking models, suitable for a high-throughput virtual screening of the Enamine chemical library. The outcome of the virtual screening was confirmed by electrophysiological assays with the best results shown for three hit compounds.
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Affiliation(s)
- Maksym Platonov
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Zabolotnogo Str., 150, 03143 Kyiv, Ukraine; (M.P.); (V.H.)
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
| | - Oleksandr Maximyuk
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine; (O.M.); (O.I.); (A.C.); (O.K.)
| | - Alexey Rayevsky
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Zabolotnogo Str., 150, 03143 Kyiv, Ukraine; (M.P.); (V.H.)
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
- Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Osypovskoho Str., 2A, 04123 Kyiv, Ukraine;
| | - Vasyl Hurmach
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Zabolotnogo Str., 150, 03143 Kyiv, Ukraine; (M.P.); (V.H.)
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
| | - Olena Iegorova
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine; (O.M.); (O.I.); (A.C.); (O.K.)
| | - Vasyl Naumchyk
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 60, 01601 Kyiv, Ukraine
| | - Elijah Bulgakov
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
- Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Osypovskoho Str., 2A, 04123 Kyiv, Ukraine;
| | - Andrii Cherninskyi
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine; (O.M.); (O.I.); (A.C.); (O.K.)
| | - Danil Ozheredov
- Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Osypovskoho Str., 2A, 04123 Kyiv, Ukraine;
| | - Serhiy V. Ryabukhin
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 60, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Academik Kukhar Str., 02660 Kyiv, Ukraine
| | - Oleg Krishtal
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine; (O.M.); (O.I.); (A.C.); (O.K.)
| | - Dmytro M. Volochnyuk
- Enamine Ltd., 78 Winston Churchill Str., 02660 Kyiv, Ukraine; (V.N.); (E.B.); (D.M.V.)
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Street 60, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Academik Kukhar Str., 02660 Kyiv, Ukraine
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9
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Marunaka Y. The Role of Ion-Transporting Proteins in Human Disease. Int J Mol Sci 2024; 25:1726. [PMID: 38339004 PMCID: PMC10855098 DOI: 10.3390/ijms25031726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
This Special Issue focuses on the significance of ion-transporting proteins, such as ion channels and transporters, providing evidence for their significant contribution to bodily and cellular functions via the regulation of signal transduction and ionic environments [...].
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Affiliation(s)
- Yoshinori Marunaka
- Medical Research Institute, Kyoto Industrial Health Association, 67 Kitatsuboi-cho, Nishinokyo, Nakagyo-ku, Kyoto 604-8472, Japan;
- Research Organization of Science and Technology, Ritsumeikan University, Kusatsu 525-8577, Japan
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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10
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Evlanenkov KK, Nikolaev MV, Potapieva NN, Bolshakov KV, Tikhonov DB. Probing the Proton-Gated ASIC Channels Using Tetraalkylammonium Ions. Biomolecules 2023; 13:1631. [PMID: 38002313 PMCID: PMC10669046 DOI: 10.3390/biom13111631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/04/2023] [Accepted: 11/05/2023] [Indexed: 11/26/2023] Open
Abstract
The action of tetraalkylammonium ions, from tetrametylammonium (TMA) to tetrapentylammonium (TPtA), on the recombinant and native acid-sensing ion channels (ASICs) was studied using the patch-clamp approach. The responses of ASIC1a, ASIC2a, and native heteromeric ASICs were inhibited by TPtA. The peak currents through ASIC3 were unaffected, whereas the steady-state currents were significantly potentiated. This effect was characterized by an EC50 value of 1.22 ± 0.12 mM and a maximal effect of 3.2 ± 0.5. The effects of TPtA were voltage-independent but significantly decreased under conditions of strong acidification, which caused saturation of ASIC responses. Molecular modeling predicted TPtA binding in the acidic pocket of closed ASICs. Bound TPtA can prevent acidic pocket collapse through a process involving ASIC activation and desensitization. Tetraethylammonium (TEA) inhibited ASIC1a and native ASICs. The effect was independent of the activating pH but decreased with depolarization, suggesting a pore-blocking mechanism.
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Affiliation(s)
| | | | | | | | - Denis B. Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg 194223, Russia or (K.K.E.); (M.V.N.); or (N.N.P.); or (K.V.B.)
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11
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Rook ML, McCullock TW, Couch T, Lueck JD, MacLean DM. Photomodulation of the ASIC1a acidic pocket destabilizes the open state. Protein Sci 2023; 32:e4800. [PMID: 37805833 PMCID: PMC10599103 DOI: 10.1002/pro.4800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 09/25/2023] [Accepted: 10/03/2023] [Indexed: 10/09/2023]
Abstract
Acid-sensing ion channels (ASICs) are important players in detecting extracellular acidification throughout the brain and body. ASICs have large extracellular domains containing two regions replete with acidic residues: the acidic pocket, and the palm domain. In the resting state, the acidic pocket is in an expanded conformation but collapses in low pH conditions as the acidic side chains are neutralized. Thus, extracellular acidification has been hypothesized to collapse the acidic pocket that, in turn, ultimately drives channel activation. However, several observations run counter to this idea. To explore how collapse or mobility of the acidic pocket is linked to channel gating, we employed two distinct tools. First, we incorporated the photocrosslinkable noncanonical amino acids (ncAAs) 4-azido-L-phenylalanine (AzF) or 4-benzoyl-L-phenylalanine (BzF) into several positions in the acidic pocket. At both E315 and Y318, AzF incorporation followed by UV irradiation led to right shifts in pH response curves and accelerations of desensitization and deactivation, consistent with restrictions of acidic pocket mobility destabilizing the open state. Second, we reasoned that because Cl- ions are found in the open and desensitized structures but absent in the resting state structures, Cl- substitution would provide insight into how stability of the pocket is linked to gating. Anion substitution resulted in faster deactivation and desensitization, consistent with the acidic pocket regulating the stability of the open state. Taken together, our data support a model where acidic pocket collapse is not essential for channel activation. Rather, collapse of the acidic pocket influences the stability of the open state of the pore.
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Affiliation(s)
- Matthew L. Rook
- Department of Pharmacology and Physiology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
| | - Tyler W. McCullock
- Department of Pharmacology and Physiology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
| | - Tyler Couch
- Department of Pharmacology and Physiology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
| | - John D. Lueck
- Department of Pharmacology and Physiology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
- Deparment of Neurology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
- Center for RNA BiologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - David M. MacLean
- Department of Pharmacology and Physiology, School of Medicine and DentistryUniversity of RochesterRochesterNew YorkUSA
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12
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Liu F, Dang Y, Li L, Feng H, Li J, Wang H, Zhang X, Zhang Z, Ye S, Tian Y, Chen Q. Structure and mechanism of a neuropeptide-activated channel in the ENaC/DEG superfamily. Nat Chem Biol 2023; 19:1276-1285. [PMID: 37550431 DOI: 10.1038/s41589-023-01401-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 07/10/2023] [Indexed: 08/09/2023]
Abstract
Phe-Met-Arg-Phe-amide (FMRFamide)-activated sodium channels (FaNaCs) are a family of channels activated by the neuropeptide FMRFamide, and, to date, the underlying ligand gating mechanism remains unknown. Here we present the high-resolution cryo-electron microscopy structures of Aplysia californica FaNaC in both apo and FMRFamide-bound states. AcFaNaC forms a chalice-shaped trimer and possesses several notable features, including two FaNaC-specific insertion regions, a distinct finger domain and non-domain-swapped transmembrane helix 2 in the transmembrane domain (TMD). One FMRFamide binds to each subunit in a cleft located in the top-most region of the extracellular domain, with participation of residues from the neighboring subunit. Bound FMRFamide adopts an extended conformation. FMRFamide binds tightly to A. californica FaNaC in an N terminus-in manner, which causes collapse of the binding cleft and induces large local conformational rearrangements. Such conformational changes are propagated downward toward the TMD via the palm domain, possibly resulting in outward movement of the TMD and dilation of the ion conduction pore.
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Affiliation(s)
- Fenglian Liu
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Yu Dang
- State Key Laboratory of Membrane Biology, Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Lu Li
- Academy of Medical Engineering and Translational Medicine (AMT) and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin, China
| | - Hao Feng
- Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, China
| | - Jianlin Li
- Academy of Medical Engineering and Translational Medicine (AMT) and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin, China
| | - Haowei Wang
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Xu Zhang
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Zhe Zhang
- State Key Laboratory of Membrane Biology, Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China.
| | - Sheng Ye
- Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, China.
| | - Yutao Tian
- Academy of Medical Engineering and Translational Medicine (AMT) and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin, China.
| | - Qingfeng Chen
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China.
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13
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Chen Y, Yu X, Yan Z, Zhang S, Zhang J, Guo W. Role of epithelial sodium channel-related inflammation in human diseases. Front Immunol 2023; 14:1178410. [PMID: 37559717 PMCID: PMC10407551 DOI: 10.3389/fimmu.2023.1178410] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/29/2023] [Indexed: 08/11/2023] Open
Abstract
The epithelial sodium channel (ENaC) is a heterotrimer and is widely distributed throughout the kidneys, blood vessels, lungs, colons, and many other organs. The basic role of the ENaC is to mediate the entry of Na+ into cells; the ENaC also has an important regulatory function in blood pressure, airway surface liquid (ASL), and endothelial cell function. Aldosterone, serum/glucocorticoid kinase 1 (SGK1), shear stress, and posttranslational modifications can regulate the activity of the ENaC; some ion channels also interact with the ENaC. In recent years, it has been found that the ENaC can lead to immune cell activation, endothelial cell dysfunction, aggravated inflammation involved in high salt-induced hypertension, cystic fibrosis, pseudohypoaldosteronism (PHA), and tumors; some inflammatory cytokines have been reported to have a regulatory role on the ENaC. The ENaC hyperfunction mediates the increase of intracellular Na+, and the elevated exchange of Na+ with Ca2+ leads to an intracellular calcium overload, which is an important mechanism for ENaC-related inflammation. Some of the research on the ENaC is controversial or unclear; we therefore reviewed the progress of studies on the role of ENaC-related inflammation in human diseases and their mechanisms.
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Affiliation(s)
- Yabin Chen
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- National Organ Transplantation (Liver &Kidney Transplantation) Physician Training Centre, Zhengzhou, China
- National Regional Medical Treatment Centre of Henan Organ Transplantation, Zhengzhou, China
| | - Xiao Yu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- National Organ Transplantation (Liver &Kidney Transplantation) Physician Training Centre, Zhengzhou, China
- National Regional Medical Treatment Centre of Henan Organ Transplantation, Zhengzhou, China
| | - Zhiping Yan
- Henan Organ Transplantation Centre, Zhengzhou, China
- Henan Engineering and Research Center for Diagnosis and Treatment of Hepatobiliary and Pancreatic Surgical Diseases, Zhengzhou, China
| | - Shuijun Zhang
- Henan Research Centre for Organ Transplantation, Zhengzhou, China
| | - Jiacheng Zhang
- Henan Key Laboratory for Digestive Organ Transplantation, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Wenzhi Guo
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Open and Key Laboratory for Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, China
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14
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Furukawa Y, Tagashira I. Aromatic amino acids in the finger domain of the FMRFamide-gated Na[Formula: see text] channel are involved in the FMRFamide recognition and the activation. Pflugers Arch 2023:10.1007/s00424-023-02817-9. [PMID: 37289212 DOI: 10.1007/s00424-023-02817-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 06/09/2023]
Abstract
FMRFamide-gated Na[Formula: see text] channel (FaNaC) is a member of the DEG/ENaC family and activated by a neuropeptide, FMRFamide. Structural information about the FMRFamide-dependent gating is, however, still elusive. Because two phenylalanines of FMRFamide are essential for the activation of FaNaC, we hypothesized that aromatic-aromatic interaction between FaNaC and FMRFamide is critical for FMRFamide recognition and/or the activation gating. Here, we focused on eight conserved aromatic residues in the finger domain of FaNaCs and tested our hypothesis by mutagenic analysis and in silico docking simulations. The mutation of conserved aromatic residues in the finger domain reduced the FMRFamide potency, suggesting that the conserved aromatic residues are involved in the FMRFamide-dependent activation. The kinetics of the FMRFamide-gated currents were also modified substantially in some mutants. Some results of docking simulations were consistent with a hypothesis that the aromatic-aromatic interaction between the aromatic residues in FaNaC and FMRFamide is involved in the FMRFamide recognition. Collectively, our results suggest that the conserved aromatic residues in the finger domain of FaNaC are important determinants of the ligand recognition and/or the activation gating in FaNaC.
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Affiliation(s)
- Yasuo Furukawa
- Laboratory of Neurobiology, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan.
- Laboratory of Neurobiology, Graduate School of Integrated Sciences of Life, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima, 739-8521, Japan.
| | - Iori Tagashira
- Laboratory of Neurobiology, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
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15
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Kaulich E, McCubbin PTN, Schafer WR, Walker DS. Physiological insight into the conserved properties of Caenorhabditis elegans acid-sensing degenerin/epithelial sodium channels. J Physiol 2023; 601:1625-1653. [PMID: 36200489 PMCID: PMC10424705 DOI: 10.1113/jp283238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are members of the diverse family of degenerin/epithelial sodium channels (DEG/ENaCs). They perform a wide range of physiological roles in healthy organisms, including in gut function and synaptic transmission, but also play important roles in disease, as acidosis is a hallmark of painful inflammatory and ischaemic conditions. We performed a screen for acid sensitivity on all 30 subunits of the Caenorhabditis elegans DEG/ENaC family using two-electrode voltage clamp in Xenopus oocytes. We found two groups of acid-sensitive DEG/ENaCs characterised by being either inhibited or activated by increasing proton concentrations. Three of these acid-sensitive C. elegans DEG/ENaCs were activated by acidic pH, making them functionally similar to the vertebrate ASICs. We also identified three new members of the acid-inhibited DEG/ENaC group, giving a total of seven additional acid-sensitive channels. We observed sensitivity to the anti-hypertensive drug amiloride as well as modulation by the trace element zinc. Acid-sensitive DEG/ENaCs were found to be expressed in both neurons and non-neuronal tissue, highlighting the likely functional diversity of these channels. Our findings provide a framework to exploit the C. elegans channels as models to study the function of these acid-sensing channels in vivo, as well as to study them as potential targets for anti-helminthic drugs. KEY POINTS: Acidosis plays many roles in healthy physiology, including synaptic transmission and gut function, but is also a key feature of inflammatory pain, ischaemia and many other conditions. Cells monitor acidosis of their surroundings via pH-sensing channels, including the acid-sensing ion channels (ASICs). These are members of the degenerin/epithelial sodium channel (DEG/ENaC) family, along with, as the name suggests, vertebrate ENaCs and degenerins of the roundworm Caenorhabditis elegans. By screening all 30 C. elegans DEG/ENaCs for pH dependence, we describe, for the first time, three acid-activated members, as well as three additional acid-inhibited channels. We surveyed both groups for sensitivity to amiloride and zinc; like their mammalian counterparts, their currents can be blocked, enhanced or unaffected by these modulators. Likewise, they exhibit diverse ion selectivity. Our findings underline the diversity of acid-sensitive DEG/ENaCs across species and provide a comparative resource for better understanding the molecular basis of their function.
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Affiliation(s)
- Eva Kaulich
- Neurobiology DivisionMRC Laboratory of Molecular BiologyCambridgeUK
| | | | - William R. Schafer
- Neurobiology DivisionMRC Laboratory of Molecular BiologyCambridgeUK
- Department of BiologyKU LeuvenLeuvenBelgium
| | - Denise S. Walker
- Neurobiology DivisionMRC Laboratory of Molecular BiologyCambridgeUK
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16
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Teng B, Kaplan J, Liang Z, Chyung KS, Goldschen-Ohm MP, Liman ER. Zinc activation of OTOP proton channels identifies structural elements of the gating apparatus. eLife 2023; 12:85317. [PMID: 37053086 PMCID: PMC10101688 DOI: 10.7554/elife.85317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
Otopetrin proteins (OTOPs) form proton-selective ion channels that are expressed in diverse cell types where they mediate detection of acids or regulation of pH. In vertebrates there are three family members: OTOP1 is required for formation of otoconia in the vestibular system and it forms the receptor for sour taste, while the functions of OTOP2 and OTOP3 are not yet known. Importantly, the gating mechanisms of any of the OTOP channels are not well understood. Here, we show that zinc (Zn2+), as well as other transition metals including copper (Cu2+), potently activates murine OTOP3 (mOTOP3). Zn2+ pre-exposure increases the magnitude of mOTOP3 currents to a subsequent acid stimulus by as much as 10-fold. In contrast, mOTOP2 currents are insensitive to activation by Zn2+. Swapping the extracellular tm 11-12 linker between mOTOP3 and mOTOP2 was sufficient to eliminate Zn2+ activation of mOTOP3 and confer Zn2+ activation on mOTOP2. Mutation to alanine of H531 and E535 within the tm 11-12 linker and H234 and E238 within the 5-6 linker reduced or eliminated activation of mOTOP3 by Zn2+, indicating that these residues likely contribute to the Zn2+ activating site. Kinetic modeling of the data is consistent with Zn2+ stabilizing the opn2+en state of the channel, competing with H+ for activation of the channels. These results establish the tm 11-12 and tm 5-6 linkers as part of the gating apparatus of OTOP channels and a target for drug discovery. Zn2+ is an essential micronutrient and its activation of OTOP channels will undoubtedly have important physiological sequelae.
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Affiliation(s)
- Bochuan Teng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
- Program in Neuroscience, University of Southern California, Los Angeles, United States
| | - Joshua Kaplan
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
- Program in Neuroscience, University of Southern California, Los Angeles, United States
| | - Ziyu Liang
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
- Program in Neuroscience, University of Southern California, Los Angeles, United States
| | - Kevin Saejin Chyung
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | | | - Emily Ruth Liman
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
- Program in Neuroscience, University of Southern California, Los Angeles, United States
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17
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Tam SW, Huffer K, Li M, Swartz KJ. Ion permeation pathway within the internal pore of P2X receptor channels. eLife 2023; 12:84796. [PMID: 36940138 PMCID: PMC10027316 DOI: 10.7554/elife.84796] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 03/07/2023] [Indexed: 03/21/2023] Open
Abstract
P2X receptor channels are trimeric ATP-activated ion channels expressed in neuronal and non-neuronal cells that are attractive therapeutic targets for human disorders. Seven subtypes of P2X receptor channels have been identified in mammals that can form both homomeric and heteromeric channels. P2X1-4 and P2X7 receptor channels are cation-selective, whereas P2X5 has been reported to have both cation and anion permeability. P2X receptor channel structures reveal that each subunit is comprised of two transmembrane helices, with both N-and C-termini on the intracellular side of the membrane and a large extracellular domain that contains the ATP binding sites at subunit interfaces. Recent structures of ATP-bound P2X receptors with the activation gate open reveal the unanticipated presence of a cytoplasmic cap over the central ion permeation pathway, leaving lateral fenestrations that may be largely buried within the membrane as potential pathways for ions to permeate the intracellular end of the pore. In the present study, we identify a critical residue within the intracellular lateral fenestrations that is readily accessible to thiol-reactive compounds from both sides of the membrane and where substitutions influence the relative permeability of the channel to cations and anions. Taken together, our results demonstrate that ions can enter or exit the internal pore through lateral fenestrations that play a critical role in determining the ion selectivity of P2X receptor channels.
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Affiliation(s)
- Stephanie W Tam
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kate Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Mufeng Li
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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18
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Komarova MS, Bukharev AR, Potapieva NN, Tikhonov DB. Modulation of Slow Desensitization (Tachyphylaxis) of Acid-Sensing Ion Channel (ASIC)1a. Cell Mol Neurobiol 2023; 43:771-783. [PMID: 35201495 DOI: 10.1007/s10571-022-01207-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/11/2022] [Indexed: 02/03/2023]
Abstract
Among the proton-activated channels of the ASIC family, ASIC1a exhibits a specific tachyphylaxis phenomenon in the form of a progressive decrease in the response amplitude during a series of activations. This process is well known, but its mechanism is poorly understood. Here, we demonstrated a partial reversibility of this effect using long-term whole-cell recording of CHO cells transfected with rASIC1a cDNA. Thus, tachyphylaxis represents a slow desensitization of ASIC1a. Prolonged acidifications provided the same recovery from slow desensitization as short acidifications of the same frequency. Slow desensitization and steady-state desensitization are independent processes although the latter attenuates the development of the former. We found that drugs which facilitate ASIC1a activation (e.g., amitriptyline) cause an enhancement of slow desensitization, while inhibition of ASIC1a by 9-aminoacridine attenuates this process. Overall, for a broad variety of exposures, including increased calcium concentration, different pH conditions, and modulating drugs, we found a correlation between their effects on ASIC1a response amplitude and the development of slow desensitization. Thus, our results demonstrate that slow desensitization occurs only when ASIC1a is in the open state.
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Affiliation(s)
- Margarita S Komarova
- Laboratory of Biophysics of Synaptic Processes, I.M Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Andrey R Bukharev
- Laboratory of Biophysics of Synaptic Processes, I.M Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Natalia N Potapieva
- Laboratory of Biophysics of Synaptic Processes, I.M Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Denis B Tikhonov
- Laboratory of Biophysics of Synaptic Processes, I.M Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
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19
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Korkosh VS, Tikhonov DB. Analysis of residue-residue interactions in the structures of ASIC1a suggests possible gating mechanisms. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:111-119. [PMID: 36690863 DOI: 10.1007/s00249-023-01628-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 01/25/2023]
Abstract
The gating mechanism of acid-sensitive ion channels (ASICs) remains unclear, despite the availability of atomic-scale structures in various functional states. The collapse of the acidic pocket and structural changes in the low-palm region are assumed to trigger activation. For the acidic pocket, protonation of some residues can minimize repulsion in the collapsed conformation. The relationship between low-palm rearrangements and gating is unknown. In this work, we performed a Monte Carlo energy optimization of known ASIC1a structures and determined the residue-residue interactions in different functional states. For rearrangements in the acidic pocket, our results are consistent with previously proposed mechanisms, although significant complexity was revealed for the residue-residue interactions. The data support the proposal of a gating mechanism in the low-palm region, in which residues E80 and E417 share a proton to activate the channel.
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Affiliation(s)
- Vyacheslav S Korkosh
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Denis B Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia.
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20
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Evlanenkov KK, Komarova MS, Dron MY, Nikolaev MV, Zhukovskaya ON, Gurova NA, Tikhonov DB. Derivatives of 2-aminobenzimidazole potentiate ASIC open state with slow kinetics of activation and desensitization. Front Physiol 2023; 14:1018551. [PMID: 36711018 PMCID: PMC9878307 DOI: 10.3389/fphys.2023.1018551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
The pharmacology of acid-sensitive ion channels (ASICs) is diverse, but potent and selective modulators, for instance for ASIC2a, are still lacking. In the present work we studied the effect of five 2-aminobenzimidazole derivatives on native ASICs in rat brain neurons and recombinant receptors expressed in CHO cells using the whole-cell patch clamp method. 2-aminobenzimidazole selectively potentiated ASIC3. Compound Ru-1355 strongly enhanced responses of ASIC2a and caused moderate potentiation of native ASICs and heteromeric ASIC1a/ASIC2a. The most active compound, Ru-1199, caused the strongest potentiation of ASIC2a, but also potentiated native ASICs, ASIC1a and ASIC3. The potentiating effects depended on the pH and was most pronounced with intermediate acidifications. In the presence of high concentrations of Ru-1355 and Ru-1199, the ASIC2a responses were biphasic, the initial transient currents were followed by slow component. These slow additional currents were weakly sensitive to the acid-sensitive ion channels pore blocker diminazene. We also found that sustained currents mediated by ASIC2a and ASIC3 are less sensitive to diminazene than the peak currents. Different sensitivities of peak and sustained components to the pore-blocking drug suggest that they are mediated by different open states. We propose that the main mechanism of action of 2-aminobenzimidazole derivatives is potentiation of the open state with slow kinetics of activation and desensitization.
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Affiliation(s)
| | - Margarita S Komarova
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Mikhail Y Dron
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Maxim V Nikolaev
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Olga N Zhukovskaya
- Research Institute of Physical and Organic Chemistry, Southern Federal University, Rostov-on-Don, Russia
| | - Nataliya A Gurova
- Department of Pharmacology and Bioinformatics, Volgograd State Medical University, Volgograd, Russia
| | - Denis B Tikhonov
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia,*Correspondence: Denis B Tikhonov,
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21
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Ananchenko A, Musgaard M. Multiscale molecular dynamics simulations predict arachidonic acid binding sites in human ASIC1a and ASIC3 transmembrane domains. J Gen Physiol 2023; 155:213797. [PMID: 36625864 PMCID: PMC9836442 DOI: 10.1085/jgp.202213259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/20/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023] Open
Abstract
Acid-sensing ion channels (ASICs) play important roles in inflammatory pathways by conducting ions across the neuronal membrane in response to proton binding under acidic conditions. Recent studies have shown that ASICs can be modulated by arachidonic acid (AA), and, in the case of the ASIC3 subtype, even activated by AA at physiological pH. However, the mechanism by which these fatty acids act on the channel is still unknown. Here, we have used multiscale molecular dynamics simulations to predict a putative, general binding region of AA to models of the human ASIC protein. We have identified, in agreement with recent studies, residues in the outer leaflet transmembrane region which interact with AA. In addition, despite their similar modulation, we observe subtle differences in the AA interaction pattern between human ASIC1a and human ASIC3, which can be reversed by mutating three key residues at the outer leaflet portion of TM1. We further probed interactions with these residues in hASIC3 using atomistic simulations and identified possible AA coordinating interactions; salt bridge interactions of AA with R65hASIC3 and R68hASIC3 and AA tail interactions with the Y58hASIC3 aromatic ring. We have shown that longer fatty acid tails with more double bonds have increased relative occupancy in this region of the channel, a finding supported by recent functional studies. We further proposed that the modulatory effect of AA on ASIC does not result from changes in local membrane curvature. Rather, we speculate that it may occur through structural changes to the ion channel upon AA binding.
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Affiliation(s)
- Anna Ananchenko
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Maria Musgaard
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
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22
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Aguilar-Camacho JM, Foreman K, Jaimes-Becerra A, Aharoni R, Gründer S, Moran Y. Functional analysis in a model sea anemone reveals phylogenetic complexity and a role in cnidocyte discharge of DEG/ENaC ion channels. Commun Biol 2023; 6:17. [PMID: 36609696 PMCID: PMC9822975 DOI: 10.1038/s42003-022-04399-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/21/2022] [Indexed: 01/09/2023] Open
Abstract
Ion channels of the DEG/ENaC family share a similar structure but serve strikingly diverse biological functions, such as Na+ reabsorption, mechanosensing, proton-sensing, chemosensing and cell-cell communication via neuropeptides. This functional diversity raises the question of the ancient function of DEG/ENaCs. Using an extensive phylogenetic analysis across many different animal groups, we found a surprising diversity of DEG/ENaCs already in Cnidaria (corals, sea anemones, hydroids and jellyfish). Using a combination of gene expression analysis, electrophysiological and functional studies combined with pharmacological inhibition as well as genetic knockout in the model cnidarian Nematostella vectensis, we reveal an unanticipated role for a proton-sensitive DEG/ENaC in discharge of N. vectensis cnidocytes, the stinging cells typifying all cnidarians. Our study supports the view that DEG/ENaCs are versatile channels that have been co-opted for diverse functions since their early occurrence in animals and that respond to simple and ancient stimuli, such as omnipresent protons.
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Affiliation(s)
- Jose Maria Aguilar-Camacho
- grid.9619.70000 0004 1937 0538Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel ,grid.40803.3f0000 0001 2173 6074Present Address: Department of Biological Sciences, North Carolina State University, Raleigh, NC USA
| | - Katharina Foreman
- grid.1957.a0000 0001 0728 696XInstitute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Adrian Jaimes-Becerra
- grid.9619.70000 0004 1937 0538Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reuven Aharoni
- grid.9619.70000 0004 1937 0538Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Stefan Gründer
- grid.1957.a0000 0001 0728 696XInstitute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Yehu Moran
- grid.9619.70000 0004 1937 0538Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
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Zhou RP, Liang HY, Hu WR, Ding J, Li SF, Chen Y, Zhao YJ, Lu C, Chen FH, Hu W. Modulators of ASIC1a and its potential as a therapeutic target for age-related diseases. Ageing Res Rev 2023; 83:101785. [PMID: 36371015 DOI: 10.1016/j.arr.2022.101785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/30/2022] [Accepted: 11/07/2022] [Indexed: 11/10/2022]
Abstract
Age-related diseases have become more common with the advancing age of the worldwide population. Such diseases involve multiple organs, with tissue degeneration and cellular apoptosis. To date, there is a general lack of effective drugs for treatment of most age-related diseases and there is therefore an urgent need to identify novel drug targets for improved treatment. Acid-sensing ion channel 1a (ASIC1a) is a degenerin/epithelial sodium channel family member, which is activated in an acidic environment to regulate pathophysiological processes such as acidosis, inflammation, hypoxia, and ischemia. A large body of evidence suggests that ASIC1a plays an important role in the development of age-related diseases (e.g., stroke, rheumatoid arthritis, Huntington's disease, and Parkinson's disease.). Herein we present: 1) a review of ASIC1a channel properties, distribution, and physiological function; 2) a summary of the pharmacological properties of ASIC1a; 3) and a consideration of ASIC1a as a potential therapeutic target for treatment of age-related disease.
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Affiliation(s)
- Ren-Peng Zhou
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China
| | - Hong-Yu Liang
- The Second School of Clinical Medicine, Anhui Medical University, Hefei 230032, China
| | - Wei-Rong Hu
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
| | - Jie Ding
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China
| | - Shu-Fang Li
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China
| | - Yong Chen
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China
| | - Ying-Jie Zhao
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China
| | - Chao Lu
- First Affiliated Hospital, Anhui University of Science & Technology, Huainan 232001, China
| | - Fei-Hu Chen
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
| | - Wei Hu
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.
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24
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Lin J, Gettings SM, Talbi K, Schreiber R, Taggart MJ, Preller M, Kunzelmann K, Althaus M, Gray MA. Pharmacological inhibitors of the cystic fibrosis transmembrane conductance regulator exert off-target effects on epithelial cation channels. Pflugers Arch 2023; 475:167-179. [PMID: 36205782 PMCID: PMC9849171 DOI: 10.1007/s00424-022-02758-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 02/01/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) anion channel and the epithelial Na+ channel (ENaC) play essential roles in transepithelial ion and fluid transport in numerous epithelial tissues. Inhibitors of both channels have been important tools for defining their physiological role in vitro. However, two commonly used CFTR inhibitors, CFTRinh-172 and GlyH-101, also inhibit non-CFTR anion channels, indicating they are not CFTR specific. However, the potential off-target effects of these inhibitors on epithelial cation channels has to date not been addressed. Here, we show that both CFTR blockers, at concentrations routinely employed by many researchers, caused a significant inhibition of store-operated calcium entry (SOCE) that was time-dependent, poorly reversible and independent of CFTR. Patch clamp experiments showed that both CFTRinh-172 and GlyH-101 caused a significant block of Orai1-mediated whole cell currents, establishing that they likely reduce SOCE via modulation of this Ca2+ release-activated Ca2+ (CRAC) channel. In addition to off-target effects on calcium channels, both inhibitors significantly reduced human αβγ-ENaC-mediated currents after heterologous expression in Xenopus oocytes, but had differential effects on δβγ-ENaC function. Molecular docking identified two putative binding sites in the extracellular domain of ENaC for both CFTR blockers. Together, our results indicate that caution is needed when using these two CFTR inhibitors to dissect the role of CFTR, and potentially ENaC, in physiological processes.
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Affiliation(s)
- JinHeng Lin
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK ,grid.4991.50000 0004 1936 8948Present Address: Department of Pharmacology, University of Oxford, Oxford, OX1 3QT UK
| | - Sean M. Gettings
- grid.1006.70000 0001 0462 7212School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - Khaoula Talbi
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Rainer Schreiber
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Michael J. Taggart
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
| | - Matthias Preller
- grid.425058.e0000 0004 0473 3519Department of Natural Sciences/Institute for Functional Gene Analytics, Structural Biology Group, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Karl Kunzelmann
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Mike Althaus
- grid.1006.70000 0001 0462 7212School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU UK ,grid.425058.e0000 0004 0473 3519Present Address: Department of Natural Sciences /Institute for Functional Gene Analytics, Ion Transport Physiology Group, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Michael A. Gray
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
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25
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Osei-Owusu J, Ruan Z, Mihaljević L, Matasic DS, Chen KH, Lü W, Qiu Z. Molecular mechanism underlying desensitization of the proton-activated chloride channel PAC. eLife 2022; 11:82955. [PMID: 36547405 PMCID: PMC9779784 DOI: 10.7554/elife.82955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Desensitization is a common property of membrane receptors, including ion channels. The newly identified proton-activated chloride (PAC) channel plays an important role in regulating the pH and size of organelles in the endocytic pathway, and is also involved in acid-induced cell death. However, how the PAC channel desensitizes is largely unknown. Here, we show by patch-clamp electrophysiological studies that PAC (also known as TMEM206/ASOR) undergoes pH-dependent desensitization upon prolonged acid exposure. Through structure-guided and comprehensive mutagenesis, we identified several residues critical for PAC desensitization, including histidine (H) 98, glutamic acid (E) 94, and aspartic acid (D) 91 at the extracellular extension of the transmembrane helix 1 (TM1), as well as E107, D109, and E250 at the extracellular domain (ECD)-transmembrane domain (TMD) interface. Structural analysis and molecular dynamic simulations revealed extensive interactions between residues at the TM1 extension and those at the ECD-TMD interface. These interactions likely facilitate PAC desensitization by stabilizing the desensitized conformation of TM1, which undergoes a characteristic rotational movement from the resting and activated states to the desensitized state. Our studies establish a new paradigm of channel desensitization in this ubiquitously expressed ion channel and pave the way for future investigation of its relevance in cellular physiology and disease.
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Affiliation(s)
- James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Zheng Ruan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Ljubica Mihaljević
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Daniel S Matasic
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Kevin Hong Chen
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Wei Lü
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
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26
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Roy S, Johner N, Trendafilov V, Gautschi I, Bignucolo O, Molton O, Bernèche S, Kellenberger S. Calcium regulates acid-sensing ion channel 3 activation by competing with protons in the channel pore and at an allosteric binding site. Open Biol 2022; 12:220243. [PMID: 36541099 PMCID: PMC9768671 DOI: 10.1098/rsob.220243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The extracellular Ca2+ concentration changes locally under certain physiological and pathological conditions. Such variations affect the function of ion channels of the nervous system and consequently also neuronal signalling. We investigated here the mechanisms by which Ca2+ controls the activity of acid-sensing ion channel (ASIC) 3. ASICs are neuronal, H+-gated Na+ channels involved in several physiological and pathological processes, including the expression of fear, learning, pain sensation and neurodegeneration after ischaemic stroke. It was previously shown that Ca2+ negatively modulates the ASIC pH dependence. While protons are default activators of ASIC3, this channel can also be activated at pH7.4 by the removal of the extracellular Ca2+. Two previous studies concluded that low pH opens ASIC3 by displacing Ca2+ ions that block the channel pore at physiological pH. We show here that an acidic residue, distant from the pore, together with pore residues, controls the modulation of ASIC3 by Ca2+. Our study identifies a new regulatory site in ASIC3 and demonstrates that ASIC3 activation involves an allosteric mechanism together with Ca2+ unbinding from the channel pore. We provide a molecular analysis of a regulatory mechanism found in many ion channels.
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Affiliation(s)
- Sophie Roy
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland
| | - Niklaus Johner
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland,Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Viktor Trendafilov
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland
| | - Ivan Gautschi
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland
| | - Olivier Bignucolo
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland,Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Ophélie Molton
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland
| | - Simon Bernèche
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland,Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Stephan Kellenberger
- Department of biomedical Sciences, University of Lausanne, 1011 Lausanne, Switzerland
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27
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Zhigulin AS, Tikhonov DB, Barygin OI. Mechanisms of acid-sensing ion channels inhibition by nafamostat, sepimostat and diminazene. Eur J Pharmacol 2022; 938:175394. [PMID: 36403685 DOI: 10.1016/j.ejphar.2022.175394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/27/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022]
Abstract
Acid-sensing ion channels (ASICs) are blocked by many cationic compounds. Mechanisms of action, which may include pore block, modulation of activation and desensitization, need systematic analysis to allow predictable design of new potent and selective drugs. In this work, we studied the action of the serine protease inhibitors nafamostat, sepimostat, gabexate and camostat, on native ASICs in rat giant striatal interneurons and recombinant ASIC1a and ASIC2a channels, and compared it to that of well-known small molecule ASIC blocker diminazene. All these compounds have positively charged amidine and/or guanidine groups in their structure. Nafamostat, sepimostat and diminazene inhibited pH 6.5-induced currents in rat striatal interneurons at -80 mV holding voltage with IC50 values of 0.78 ± 0.12 μM, 2.4 ± 0.3 μM and 0.40 ± 0.09 μM, respectively, whereas camostat and gabexate were practically ineffective. The inhibition by nafamostat, sepimostat and diminazene was voltage-dependent evidencing binding in the channel pore. They were not trapped in the closed channels, suggesting "foot-in-the-door" mechanism of action. The inhibitory activity of nafamostat, sepimostat and diminazene was similar in experiments on native ASICs and recombinant ASIC1a channels, while all of them were drastically less active against ASIC2a channels. According to our molecular modeling, three active compounds bind in the channel pore between Glu 433 and Ala 444 in a similar way. In view of the relative safety of nafamostat for clinical use in humans, it can be considered as a potential candidate for the treatment of pathophysiological conditions linked to ASICs disfunction, including inflammatory pain and ischemic stroke.
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Affiliation(s)
- Arseniy S Zhigulin
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, Saint-Petersburg, Russia
| | - Denis B Tikhonov
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, Saint-Petersburg, Russia
| | - Oleg I Barygin
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, Saint-Petersburg, Russia.
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28
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Jang W, Lim JY, Kang S, Kim M, Hwang SW, Kim C. Drosophila ppk19 encodes a proton-gated and mechanosensitive ion channel. Sci Rep 2022; 12:18346. [PMID: 36319833 PMCID: PMC9626565 DOI: 10.1038/s41598-022-23236-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/27/2022] [Indexed: 11/05/2022] Open
Abstract
In Drosophila larvae, nociceptive mdIV sensory neurons detect diverse noxious stimuli and prompt a nociceptive rolling response. Intriguingly, the same neurons also regulate stereotyped larval movement. The channels responsible for transducing these stimuli into electric signals are not yet fully identified. Here we undertook genetic and electrophysiological analysis of Ppk19, a member of the Deg/ENaC family of cationic channels. ppk19 mutants exhibited an impaired nociceptive rolling response upon mechanical force and acid, but no impairment in response to noxious temperature and gentle touch. Mutants also exhibited defective larval movement. RNAi against ppk19 in mdIV neurons likewise produced larvae with defects in mechanical and acid nociception and larval movement, but no impairment in detection of heat and gentle touch. Cultured cells transfected with ppk19 produced currents in acid and hypotonic solution, suggesting that ppk19 encodes an ion channel that responds to acid and cell swelling. Taken together, these findings suggest that Ppk19 acts in mdIV neurons as a proton- and mechano-gated ion channel to mediate acid- and mechano-responsive nociception and larval movement.
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Affiliation(s)
- Wijeong Jang
- grid.14005.300000 0001 0356 9399School of Biological Sciences and Technology, Chonnam National University, Gwangju, 61186 Korea
| | - Ji Yeon Lim
- grid.222754.40000 0001 0840 2678Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul, 02841 Korea
| | - Seyoung Kang
- grid.14005.300000 0001 0356 9399School of Biological Sciences and Technology, Chonnam National University, Gwangju, 61186 Korea
| | - Minseok Kim
- grid.222754.40000 0001 0840 2678Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul, 02841 Korea
| | - Sun Wook Hwang
- grid.222754.40000 0001 0840 2678Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, Seoul, 02841 Korea
| | - Changsoo Kim
- grid.14005.300000 0001 0356 9399School of Biological Sciences and Technology, Chonnam National University, Gwangju, 61186 Korea
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29
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Venom-derived pain-causing toxins: insights into sensory neuron function and pain mechanisms. Pain 2022; 163:S46-S56. [DOI: 10.1097/j.pain.0000000000002701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/19/2022] [Indexed: 11/25/2022]
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30
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Kaulich E, Grundy LJ, Schafer WR, Walker DS. The diverse functions of the DEG/ENaC family: linking genetic and physiological insights. J Physiol 2022; 601:1521-1542. [PMID: 36314992 PMCID: PMC10148893 DOI: 10.1113/jp283335] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
The DEG/ENaC family of ion channels was defined based on the sequence similarity between degenerins (DEG) from the nematode Caenorhabditis elegans and subunits of the mammalian epithelial sodium channel (ENaC), and also includes a diverse array of non-voltage-gated cation channels from across animal phyla, including the mammalian acid-sensing ion channels (ASICs) and Drosophila pickpockets. ENaCs and ASICs have wide ranging medical importance; for example, ENaCs play an important role in respiratory and renal function, and ASICs in ischaemia and inflammatory pain, as well as being implicated in memory and learning. Electrophysiological approaches, both in vitro and in vivo, have played an essential role in establishing the physiological properties of this diverse family, identifying an array of modulators and implicating them in an extensive range of cellular functions, including mechanosensation, acid sensation and synaptic modulation. Likewise, genetic studies in both invertebrates and vertebrates have played an important role in linking our understanding of channel properties to function at the cellular and whole animal/behavioural level. Drawing together genetic and physiological evidence is essential to furthering our understanding of the precise cellular roles of DEG/ENaC channels, with the diversity among family members allowing comparative physiological studies to dissect the molecular basis of these diverse functions.
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Affiliation(s)
- Eva Kaulich
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - Laura J Grundy
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK.,Department of Biology, KU Leuven, Leuven, Belgium
| | - Denise S Walker
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
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31
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Verkest C, Salinas M, Diochot S, Deval E, Lingueglia E, Baron A. Mechanisms of Action of the Peptide Toxins Targeting Human and Rodent Acid-Sensing Ion Channels and Relevance to Their In Vivo Analgesic Effects. Toxins (Basel) 2022; 14:toxins14100709. [PMID: 36287977 PMCID: PMC9612379 DOI: 10.3390/toxins14100709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 11/16/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are voltage-independent H+-gated cation channels largely expressed in the nervous system of rodents and humans. At least six isoforms (ASIC1a, 1b, 2a, 2b, 3 and 4) associate into homotrimers or heterotrimers to form functional channels with highly pH-dependent gating properties. This review provides an update on the pharmacological profiles of animal peptide toxins targeting ASICs, including PcTx1 from tarantula and related spider toxins, APETx2 and APETx-like peptides from sea anemone, and mambalgin from snake, as well as the dimeric protein snake toxin MitTx that have all been instrumental to understanding the structure and the pH-dependent gating of rodent and human cloned ASICs and to study the physiological and pathological roles of native ASICs in vitro and in vivo. ASICs are expressed all along the pain pathways and the pharmacological data clearly support a role for these channels in pain. ASIC-targeting peptide toxins interfere with ASIC gating by complex and pH-dependent mechanisms sometimes leading to opposite effects. However, these dual pH-dependent effects of ASIC-inhibiting toxins (PcTx1, mambalgin and APETx2) are fully compatible with, and even support, their analgesic effects in vivo, both in the central and the peripheral nervous system, as well as potential effects in humans.
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Affiliation(s)
- Clément Verkest
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Department of Anesthesiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Miguel Salinas
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Sylvie Diochot
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Emmanuel Deval
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Eric Lingueglia
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Anne Baron
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Correspondence:
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32
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Hauser F, Koch TL, Grimmelikhuijzen CJP. Review: The evolution of peptidergic signaling in Cnidaria and Placozoa, including a comparison with Bilateria. Front Endocrinol (Lausanne) 2022; 13:973862. [PMID: 36213267 PMCID: PMC9545775 DOI: 10.3389/fendo.2022.973862] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Bilateria have bilateral symmetry and are subdivided into Deuterostomia (animals like vertebrates) and Protostomia (animals like insects and mollusks). Neuropeptides occur in both Proto- and Deuterostomia and they are frequently structurally related across these two lineages. For example, peptides belonging to the oxytocin/vasopressin family exist in both clades. The same is true for the G protein-coupled receptors (GPCRs) of these peptides. These observations suggest that these neuropeptides and their GPCRs were already present in the common ancestor of Proto- and Deuterostomia, which lived about 700 million years ago (MYA). Furthermore, neuropeptides and their GPCRs occur in two early-branching phyla that diverged before the emergence of Bilateria: Cnidaria (animals like corals and sea anemones), and Placozoa (small disk-like animals, feeding on algae). The sequences of these neuropeptides and their GPCRs, however, are not closely related to those from Bilateria. In addition, cnidarian neuropeptides and their receptors are not closely related to those from Placozoa. We propose that the divergence times between Cnidaria, Placozoa, and Bilateria might be too long for recognizing sequence identities. Leucine-rich repeats-containing GPCRs (LGRs) are a special class of GPCRs that are characterized by a long N-terminus containing 10-20 leucine-rich domains, which are used for ligand binding. Among the ligands for LGRs are dimeric glycoprotein hormones, and insulin-like peptides, such as relaxin. LGRs have been found not only in Proto- and Deuterostomia, but also in early emerging phyla, such as Cnidaria and Placozoa. Humans have eight LGRs. In our current review, we have revisited the annotations of LGRs from the sea anemone Nematostella vectensis and the placozoan Trichoplax adhaerens. We identified 13 sea anemone LGRs and no less than 46 LGRs from T. adhaerens. All eight human LGRs appear to have orthologues in sea anemones and placozoans. LGRs and their ligands, therefore, have a long evolutionary history, going back to the common ancestor of Cnidaria and Placozoa.
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Affiliation(s)
- Frank Hauser
- Section for Cell and Neurobiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas L. Koch
- Section for Cell and Neurobiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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33
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Acidosis induces RIPK1-dependent death of glioblastoma stem cells via acid-sensing ion channel 1a. Cell Death Dis 2022; 13:702. [PMID: 35961983 PMCID: PMC9374719 DOI: 10.1038/s41419-022-05139-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 01/21/2023]
Abstract
Eliciting regulated cell death, like necroptosis, is a potential cancer treatment. However, pathways eliciting necroptosis are poorly understood. It has been reported that prolonged activation of acid-sensing ion channel 1a (ASIC1a) induces necroptosis in mouse neurons. Glioblastoma stem cells (GSCs) also express functional ASIC1a, but whether prolonged activation of ASIC1a induces necroptosis in GSCs is unknown. Here we used a tumorsphere formation assay to show that slight acidosis (pH 6.6) induces necrotic cell death in a manner that was sensitive to the necroptosis inhibitor Nec-1 and to the ASIC1a antagonist PcTx1. In addition, genetic knockout of ASIC1a rendered GSCs resistant to acid-induced reduction in tumorsphere formation, while the ASIC1 agonist MitTx1 reduced tumorsphere formation also at neutral pH. Finally, a 20 amino acid fragment of the ASIC1 C-terminus, thought to interact with the necroptosis kinase RIPK1, was sufficient to reduce the formation of tumorspheres. Meanwhile, the genetic knockout of MLKL, the executive protein in the necroptosis cascade, did not prevent a reduction in tumor sphere formation, suggesting that ASIC1a induced an alternative cell death pathway. These findings demonstrate that ASIC1a is a death receptor on GSCs that induces cell death during prolonged acidosis. We propose that this pathway shapes the evolution of a tumor in its acidic microenvironment and that pharmacological activation of ASIC1a might be a potential new strategy in tumor therapy.
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Osei-Owusu J, Kots E, Ruan Z, Mihaljević L, Chen KH, Tamhaney A, Ye X, Lü W, Weinstein H, Qiu Z. Molecular determinants of pH sensing in the proton-activated chloride channel. Proc Natl Acad Sci U S A 2022; 119:e2200727119. [PMID: 35878032 PMCID: PMC9351481 DOI: 10.1073/pnas.2200727119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/31/2022] [Indexed: 01/27/2023] Open
Abstract
In response to acidic pH, the widely expressed proton-activated chloride (PAC) channel opens and conducts anions across cellular membranes. By doing so, PAC plays an important role in both cellular physiology (endosome acidification) and diseases associated with tissue acidosis (acid-induced cell death). Despite the available structural information, how proton binding in the extracellular domain (ECD) leads to PAC channel opening remains largely unknown. Here, through comprehensive mutagenesis and electrophysiological studies, we identified several critical titratable residues, including two histidine residues (H130 and H131) and an aspartic acid residue (D269) at the distal end of the ECD, together with the previously characterized H98 at the transmembrane domain-ECD interface, as potential pH sensors for human PAC. Mutations of these residues resulted in significant changes in pH sensitivity. Some combined mutants also exhibited large basal PAC channel activities at neutral pH. By combining molecular dynamics simulations with structural and functional analysis, we further found that the β12 strand at the intersubunit interface and the associated "joint region" connecting the upper and lower ECDs allosterically regulate the proton-dependent PAC activation. Our studies suggest a distinct pH-sensing and gating mechanism of this new family of ion channels sensitive to acidic environment.
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Affiliation(s)
- James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ekaterina Kots
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065
| | - Zheng Ruan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503
| | - Ljubica Mihaljević
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Kevin Hong Chen
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ami Tamhaney
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Xinyu Ye
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503
| | - Wei Lü
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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35
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Vaithia A, Kellenberger S. Probing conformational changes during activation of ASIC1a by an optical tweezer and by methanethiosulfonate-based cross-linkers. PLoS One 2022; 17:e0270762. [PMID: 35802631 PMCID: PMC9269482 DOI: 10.1371/journal.pone.0270762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/16/2022] [Indexed: 11/19/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are neuronal, proton-gated, Na+-selective ion channels. They are involved in various physiological and pathological processes such as neurodegeneration after stroke, pain sensation, fear behavior and learning. To obtain information on the activation mechanism of ASIC1a, we attempted in this study to impose distance constraints between paired residues in different channel domains by using cross-linkers reacting with engineered Cys residues, and we measured how this affected channel function. First, the optical tweezer 4′-Bis(maleimido)azobenzene (BMA) was used, whose conformation changes depending on the wavelength of applied light. After exposure of channel mutants to BMA, an activation of the channel by light was only observed with a mutant containing a Cys mutation in the extracellular pore entry, I428C. Western blot analysis indicated that BMA did not cross-link Cys428 residues. Extracellular application of methanethiosulfonate (MTS) cross-linkers of different lengths changed the properties of several Cys mutants, in many cases likely without cross-linking two Cys residues. Our observations suggest that intersubunit cross-linking occurred in the wrist mutant A425C and intrasubunit cross-linking in the acidic pocket mutant D237C/I312C. In these mutants, exposure to cross-linkers favored a non-conducting channel conformation and induced an acidic shift of the pH dependence and a decrease of the maximal current amplitude. Overall, the cross-linking approaches appeared to be inefficient, possibly due to the geometrical requirements for successful reactions of the two ends of the cross-linking compound.
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Affiliation(s)
- Anand Vaithia
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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36
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Wang Y, Hu X, Sun Y, Huang Y. The Role of ASIC1a in Inflammatory Immune Diseases: A Potential Therapeutic Target. Front Pharmacol 2022; 13:942209. [PMID: 35873582 PMCID: PMC9304623 DOI: 10.3389/fphar.2022.942209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/20/2022] [Indexed: 11/26/2022] Open
Abstract
It is acknowledged that chronic inflammation is associated with a rise in extracellular proton concentrations. The acid-sensing ion channel 1a (ASIC1a) belongs to the extracellular H+-activated cation channel family. Recently, many studies have been conducted on ASIC1a and inflammatory immune diseases. Here, in this review, we will focus on the role of ASIC1a in several inflammatory immune diseases so as to provide new perspectives for clinical treatment.
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Affiliation(s)
- Yinghong Wang
- Department of Pharmacy, Anhui Provincial Cancer Hospital, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xiaojie Hu
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
| | - Yancai Sun
- Department of Pharmacy, Anhui Provincial Cancer Hospital, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- *Correspondence: Yancai Sun, ; Yan Huang,
| | - Yan Huang
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
- *Correspondence: Yancai Sun, ; Yan Huang,
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Klipp RC, Bankston JR. Structural determinants of acid-sensing ion channel potentiation by single chain lipids. J Gen Physiol 2022; 154:e202213156. [PMID: 35583813 PMCID: PMC9120901 DOI: 10.1085/jgp.202213156] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/02/2022] [Indexed: 01/07/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are sensitized to activation by inflammatory mediators such as the polyunsaturated fatty acid (PUFA) arachidonic acid (AA). Previous work has shown that AA can potentiate ASIC currents at subsaturating proton concentrations, but the structural mechanisms of this change in gating are not understood. Here we show that PUFAs cause multiple gating changes in ASIC3, including shifting the pH dependence of activation, slowing the rate of desensitization, and increasing the current even at a saturating pH. The impact on gating depends on the nature of both the head and tail of the lipid, with the head group structure primarily determining the magnitude of the effect on the channel. An N-acyl amino acid (NAAA), arachidonyl glycine (AG), is such a strong regulator that it can act as a ligand at neutral pH. Mutation of an arginine in the outer segment of TM1 (R64) eliminated the effect of docosahexaenoic acid (DHA) even at high concentrations, suggesting a potential interaction site for the lipid on the channel. Our results suggest a model in which PUFAs bind to ASICs via both their tail group and an electrostatic interaction between the negatively charged PUFA head group and the positively charged arginine side chain. These data provide the first look at the structural features of lipids that are important for modulating ASICs and suggest a potential binding site for PUFAs on the channel.
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Affiliation(s)
- Robert C. Klipp
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - John R. Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
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38
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Oken AC, Krishnamurthy I, Savage JC, Lisi NE, Godsey MH, Mansoor SE. Molecular Pharmacology of P2X Receptors: Exploring Druggable Domains Revealed by Structural Biology. Front Pharmacol 2022; 13:925880. [PMID: 35784697 PMCID: PMC9248971 DOI: 10.3389/fphar.2022.925880] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/10/2022] [Indexed: 11/18/2022] Open
Abstract
Extracellular ATP is a critical signaling molecule that is found in a wide range of concentrations across cellular environments. The family of nonselective cation channels that sense extracellular ATP, termed P2X receptors (P2XRs), is composed of seven subtypes (P2X1-P2X7) that assemble as functional homotrimeric and heterotrimeric ion channels. Each P2XR is activated by a distinct concentration of extracellular ATP, spanning from high nanomolar to low millimolar. P2XRs are implicated in a variety of physiological and pathophysiological processes in the cardiovascular, immune, and central nervous systems, corresponding to the spatiotemporal expression, regulation, and activation of each subtype. The therapeutic potential of P2XRs is an emerging area of research in which structural biology has seemingly exceeded medicinal chemistry, as there are several published P2XR structures but currently no FDA-approved drugs targeting these ion channels. Cryogenic electron microscopy is ideally suited to facilitate structure-based drug design for P2XRs by revealing and characterizing novel ligand-binding sites. This review covers structural elements in P2XRs including the extracellular orthosteric ATP-binding site, extracellular allosteric modulator sites, channel pore, and cytoplasmic substructures, with an emphasis on potential therapeutic ligand development.
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Affiliation(s)
- Adam C. Oken
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
| | - Ipsita Krishnamurthy
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
| | - Jonathan C. Savage
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
| | - Nicolas E. Lisi
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
| | - Michael H. Godsey
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
| | - Steven E. Mansoor
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
- *Correspondence: Steven E. Mansoor,
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39
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Dandamudi M, Hausen H, Lynagh T. Comparative analysis defines a broader FMRFamide-gated sodium channel family and determinants of neuropeptide sensitivity. J Biol Chem 2022; 298:102086. [PMID: 35636513 PMCID: PMC9234716 DOI: 10.1016/j.jbc.2022.102086] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 12/23/2022] Open
Abstract
FMRFamide (Phe-Met-Arg-Phe-amide, FMRFa) and similar neuropeptides are important physiological modulators in most invertebrates, but the molecular basis of FMRFa activity at its receptors is unknown. We therefore sought to identify the molecular determinants of FMRFa potency against one of its native targets, the excitatory FMRFa-gated sodium channel (FaNaC) from gastropod mollusks. Using molecular phylogenetics and electrophysiological measurement of neuropeptide activity, we identified a broad FaNaC family that includes mollusk and annelid channels gated by FMRFa, FVRIamides, and/or Wamides (or myoinhibitory peptides). A comparative analysis of this broader FaNaC family and other channels from the overarching degenerin (DEG)/epithelial sodium channel (ENaC) superfamily, incorporating mutagenesis and experimental dissection of channel function, identified a pocket of amino acid residues that determines activation of FaNaCs by neuropeptides. Although this pocket has diverged in distantly related DEG/ENaC channels that are activated by other ligands but enhanced by FMRFa, such as mammalian acid-sensing ion channels, we show that it nonetheless contains residues that determine enhancement of those channels by similar peptides. This study thus identifies amino acid residues that determine FMRFa neuropeptide activity at FaNaC receptor channels and illuminates the evolution of ligand recognition in one branch of the DEG/ENaC superfamily of ion channels.
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Affiliation(s)
- Mowgli Dandamudi
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway; Department of Earth Science, University of Bergen, Bergen, Norway
| | - Timothy Lynagh
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.
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40
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Vallée C, Howlin BJ, Lewis R. Single ion free energy calculation in ASIC1: the importance of the HG loop. Phys Chem Chem Phys 2022; 24:13824-13830. [PMID: 35616206 DOI: 10.1039/d2cp01563c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acid Sensing Ion Channels (ASICs) are one of the most studied channels of the Epithelial Sodium Channel/Degenerin (ENaC/DEG) superfamily. They are responsible for excitatory responses following acidification of the extracellular medium and are involved in several important physiological roles. The ASIC1 subunit can form a functional homotrimeric channel and its structure is currently the most characterised of the whole ENaC/DEG family. Here we computed the free energy profiles for single ion permeation in two different structures of ASIC1 using both Na+ and Cl- as permeating ions. The first structure is the open structure of the channel from the PDB entry 4NTW, and the second structure is the closed structure with the re-entrant loop which contains the highly conserved 'HG' motif form PDB entry 6VTK. Both structures show cation selective free energy profiles, however the profiles of the permeating Na+ differ significantly between the two structures. Indeed, whereas there is only a small energetically favorable (-0.5 kcal mol-1) location for Na+ in the open channel (4NTW) near the end of the pore, we observed a clear ion binding site (-7.8 kcal mol-1) located in between the 'GAS' belt and the 'HG' loop for the channel containing the re-entrant loop (6VTK). Knowing that the 'GAS' motif was determined as the selectivity filter, our results support previous observations while addressing the importance of the 'HG' motif for the interactions between the pore and the permeating cations.
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Affiliation(s)
- Cédric Vallée
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK. .,Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK.,School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK
| | - Brendan J Howlin
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK. .,Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Rebecca Lewis
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK. .,School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK
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41
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Mernea M, Ulăreanu RȘ, Cucu D, Al-Saedi JH, Pop CE, Fendrihan S, Anghelescu GDC, Mihăilescu DF. Epithelial Sodium Channel Inhibition by Amiloride Addressed with THz Spectroscopy and Molecular Modeling. Molecules 2022; 27:3271. [PMID: 35630748 PMCID: PMC9144217 DOI: 10.3390/molecules27103271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/08/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
THz spectroscopy is important for the study of ion channels because it directly addresses the low frequency collective motions relevant for their function. Here we used THz spectroscopy to investigate the inhibition of the epithelial sodium channel (ENaC) by its specific blocker, amiloride. Experiments were performed on A6 cells' suspensions, which are cells overexpressing ENaC derived from Xenopus laevis kidney. THz spectra were investigated with or without amiloride. When ENaC was inhibited by amiloride, a substantial increase in THz absorption was noticed. Molecular modeling methods were used to explain the observed spectroscopic differences. THz spectra were simulated using the structural models of ENaC and ENaC-amiloride complexes built here. The agreement between the experiment and the simulations allowed us to validate the structural models and to describe the amiloride dynamics inside the channel pore. The amiloride binding site validated using THz spectroscopy agrees with previous mutagenesis studies. Altogether, our results show that THz spectroscopy can be successfully used to discriminate between native and inhibited ENaC channels and to characterize the dynamics of channels in the presence of their specific antagonist.
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Affiliation(s)
- Maria Mernea
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Roxana Ștefania Ulăreanu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dana Cucu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Jasim Hafedh Al-Saedi
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Cristian-Emilian Pop
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania;
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
| | - Sergiu Fendrihan
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
- Faculty of Medicine, University “Vasile Goldis”, Bulevardul Revoluției 94, 310025 Arad, Romania
| | - Giorgiana Diana Carmen Anghelescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dan Florin Mihăilescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
- Biometric Psychiatric Genetics Research Unit, Alexandru Obregia Psychiatric Hospital, 10 Șoseaua Berceni Str., 041914 Bucharest, Romania
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42
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von Reumont BM, Anderluh G, Antunes A, Ayvazyan N, Beis D, Caliskan F, Crnković A, Damm M, Dutertre S, Ellgaard L, Gajski G, German H, Halassy B, Hempel BF, Hucho T, Igci N, Ikonomopoulou MP, Karbat I, Klapa MI, Koludarov I, Kool J, Lüddecke T, Ben Mansour R, Vittoria Modica M, Moran Y, Nalbantsoy A, Ibáñez MEP, Panagiotopoulos A, Reuveny E, Céspedes JS, Sombke A, Surm JM, Undheim EAB, Verdes A, Zancolli G. Modern venomics-Current insights, novel methods, and future perspectives in biological and applied animal venom research. Gigascience 2022; 11:6588117. [PMID: 35640874 PMCID: PMC9155608 DOI: 10.1093/gigascience/giac048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 12/11/2022] Open
Abstract
Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.
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Affiliation(s)
- Bjoern M von Reumont
- Goethe University Frankfurt, Institute for Cell Biology and Neuroscience, Department for Applied Bioinformatics, 60438 Frankfurt am Main, Germany.,LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Frankfurt, Senckenberganlage 25, 60235 Frankfurt, Germany.,Justus Liebig University Giessen, Institute for Insectbiotechnology, Heinrich Buff Ring 26-32, 35396 Giessen, Germany
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - Agostinho Antunes
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.,Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Naira Ayvazyan
- Orbeli Institute of Physiology of NAS RA, Orbeli ave. 22, 0028 Yerevan, Armenia
| | - Dimitris Beis
- Developmental Biology, Centre for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens, Athens 11527, Greece
| | - Figen Caliskan
- Department of Biology, Faculty of Science and Letters, Eskisehir Osmangazi University, TR-26040 Eskisehir, Turkey
| | - Ana Crnković
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - Maik Damm
- Technische Universität Berlin, Department of Chemistry, Straße des 17. Juni 135, 10623 Berlin, Germany
| | | | - Lars Ellgaard
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Goran Gajski
- Institute for Medical Research and Occupational Health, Mutagenesis Unit, Ksaverska cesta 2, 10000 Zagreb, Croatia
| | - Hannah German
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
| | - Beata Halassy
- University of Zagreb, Centre for Research and Knowledge Transfer in Biotechnology, Trg Republike Hrvatske 14, 10000 Zagreb, Croatia
| | - Benjamin-Florian Hempel
- BIH Center for Regenerative Therapies BCRT, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Tim Hucho
- Translational Pain Research, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Nasit Igci
- Nevsehir Haci Bektas Veli University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, 50300 Nevsehir, Turkey
| | - Maria P Ikonomopoulou
- Madrid Institute for Advanced Studies in Food, Madrid,E28049, Spain.,The University of Queensland, St Lucia, QLD 4072, Australia
| | - Izhar Karbat
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Maria I Klapa
- Metabolic Engineering and Systems Biology Laboratory, Institute of Chemical Engineering Sciences, Foundation for Research & Technology Hellas (FORTH/ICE-HT), Patras GR-26504, Greece
| | - Ivan Koludarov
- Justus Liebig University Giessen, Institute for Insectbiotechnology, Heinrich Buff Ring 26-32, 35396 Giessen, Germany
| | - Jeroen Kool
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
| | - Tim Lüddecke
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Frankfurt, Senckenberganlage 25, 60235 Frankfurt, Germany.,Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, 35392 Gießen, Germany
| | - Riadh Ben Mansour
- Department of Life Sciences, Faculty of Sciences, Gafsa University, Campus Universitaire Siidi Ahmed Zarrouk, 2112 Gafsa, Tunisia
| | - Maria Vittoria Modica
- Dept. of Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn, Via Po 25c, I-00198 Roma, Italy
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Ayse Nalbantsoy
- Department of Bioengineering, Faculty of Engineering, Ege University, 35100 Bornova, Izmir, Turkey
| | - María Eugenia Pachón Ibáñez
- Unit of Infectious Diseases, Microbiology, and Preventive Medicine, Virgen del Rocío University Hospital, Institute of Biomedicine of Seville, 41013 Sevilla, Spain.,CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid, Spain
| | - Alexios Panagiotopoulos
- Metabolic Engineering and Systems Biology Laboratory, Institute of Chemical Engineering Sciences, Foundation for Research & Technology Hellas (FORTH/ICE-HT), Patras GR-26504, Greece.,Animal Biology Division, Department of Biology, University of Patras, Patras, GR-26500, Greece
| | - Eitan Reuveny
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Javier Sánchez Céspedes
- Unit of Infectious Diseases, Microbiology, and Preventive Medicine, Virgen del Rocío University Hospital, Institute of Biomedicine of Seville, 41013 Sevilla, Spain.,CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid, Spain
| | - Andy Sombke
- Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Joachim M Surm
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Eivind A B Undheim
- University of Oslo, Centre for Ecological and Evolutionary Synthesis, Postboks 1066 Blindern 0316 Oslo, Norway
| | - Aida Verdes
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Giulia Zancolli
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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43
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Zhang L, Wang X, Chen J, Kleyman TR, Sheng S. Accessibility of ENaC extracellular domain central core residues. J Biol Chem 2022; 298:101860. [PMID: 35339489 PMCID: PMC9052164 DOI: 10.1016/j.jbc.2022.101860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 11/20/2022] Open
Abstract
The epithelial Na+ channel (ENaC)/degenerin family has a similar extracellular architecture, where specific regulatory factors interact and alter channel gating behavior. The extracellular palm domain serves as a key link to the channel pore. In this study, we used cysteine-scanning mutagenesis to assess the functional effects of Cys-modifying reagents on palm domain β10 strand residues in mouse ENaC. Of the 13 ENaC α subunit mutants with Cys substitutions examined, only mutants at sites in the proximal region of β10 exhibited changes in channel activity in response to methanethiosulfonate reagents. Additionally, Cys substitutions at three proximal sites of β and γ subunit β10 strands also rendered mutant channels methanethiosulfonate-responsive. Moreover, multiple Cys mutants were activated by low concentrations of thiophilic Cd2+. Using the Na+ self-inhibition response to assess ENaC gating behavior, we identified four α, two β, and two γ subunit β10 strand mutations that changed the Na+ self-inhibition response. Our results suggest that the proximal regions of β10 strands in all three subunits are accessible to small aqueous compounds and Cd2+ and have a role in modulating ENaC gating. These results are consistent with a structural model of mouse ENaC that predicts the presence of aqueous tunnels adjacent to the proximal part of β10 and with previously resolved structures of a related family member where palm domain structural transitions were observed with channels in an open or closed state.
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Affiliation(s)
- Lei Zhang
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xueqi Wang
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jingxin Chen
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas R Kleyman
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| | - Shaohu Sheng
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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44
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Qi X, Lu JF, Huang ZY, Liu YJ, Cai LB, Wen XL, Song XL, Xiong J, Sun PY, Zhang H, Zhang TT, Zhao X, Jiang Q, Li Y, Krishtal O, Hou LC, Zhu MX, Xu TL. Pharmacological Validation of ASIC1a as a Druggable Target for Neuroprotection in Cerebral Ischemia Using an Intravenously Available Small Molecule Inhibitor. Front Pharmacol 2022; 13:849498. [PMID: 35401212 PMCID: PMC8988055 DOI: 10.3389/fphar.2022.849498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/28/2022] [Indexed: 12/28/2022] Open
Abstract
Acidosis is a hallmark of ischemic stroke and a promising neuroprotective target for preventing neuronal injury. Previously, genetic manipulations showed that blockade of acid-sensing ion channel 1a (ASIC1a)-mediated acidotoxicity could dramatically alleviate the volume of brain infarct and restore neurological function after cerebral ischemia. However, few pharmacological candidates have been identified to exhibit efficacy on ischemic stroke through inhibition of ASIC1a. In this work, we examined the ability of a toxin-inspired compound 5b (C5b), previously found to effectively inhibit ASIC1a in vitro, to exert protective effects in animal models of ischemic stroke in vivo. We found that C5b exerts significant neuroprotective effects not only in acid-induced neuronal death in vitro but also ischemic brain injury in vivo, suggesting that ASIC1a is a druggable target for therapeutic development. More importantly, C5b is able to cross the blood brain barrier and significantly reduce brain infarct volume when administered intravenously in the ischemic animal model, highlighting its systemic availability for therapies against neurodegeneration due to acidotoxicity. Together, our data demonstrate that C5b is a promising lead compound for neuroprotection through inhibiting ASIC1a, which warrants further translational studies.
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Affiliation(s)
- Xin Qi
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian-Fei Lu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zi-Yue Huang
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi-Jun Liu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lu-Bing Cai
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xin-Lan Wen
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xing-Lei Song
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Xiong
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Pei-Yi Sun
- Department of Dermatology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hao Zhang
- Department of Anesthesiology, Shanghai 10th People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ting-Ting Zhang
- Department of Anesthesiology, Shanghai 10th People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xuan Zhao
- Department of Anesthesiology, Shanghai 10th People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qin Jiang
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Li
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Oleg Krishtal
- Department of Cellular Membranology, Bogomoletz Institute of Physiology of NAS Ukraine, Kyiv, Ukraine
| | - Leng-Chen Hou
- Department of Anesthesiology, Shanghai 10th People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
- *Correspondence: Michael X. Zhu, ; Tian-Le Xu,
| | - Tian-Le Xu
- Center for Brain Science of Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Michael X. Zhu, ; Tian-Le Xu,
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45
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Hards K, Cheung CY, Waller N, Adolph C, Keighley L, Tee ZS, Harold LK, Menorca A, Bujaroski RS, Buckley BJ, Tyndall JDA, McNeil MB, Rhee KY, Opel-Reading HK, Krause K, Preiss L, Langer JD, Meier T, Hasenoehrl EJ, Berney M, Kelso MJ, Cook GM. An amiloride derivative is active against the F 1F o-ATP synthase and cytochrome bd oxidase of Mycobacterium tuberculosis. Commun Biol 2022; 5:166. [PMID: 35210534 PMCID: PMC8873251 DOI: 10.1038/s42003-022-03110-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/03/2022] [Indexed: 12/15/2022] Open
Abstract
Increasing antimicrobial resistance compels the search for next-generation inhibitors with differing or multiple molecular targets. In this regard, energy conservation in Mycobacterium tuberculosis has been clinically validated as a promising new drug target for combatting drug-resistant strains of M. tuberculosis. Here, we show that HM2-16F, a 6-substituted derivative of the FDA-approved drug amiloride, is an anti-tubercular inhibitor with bactericidal properties comparable to the FDA-approved drug bedaquiline (BDQ; Sirturo®) and inhibits the growth of bedaquiline-resistant mutants. We show that HM2-16F weakly inhibits the F1Fo-ATP synthase, depletes ATP, and affects the entry of acetyl-CoA into the Krebs cycle. HM2-16F synergizes with the cytochrome bcc-aa3 oxidase inhibitor Q203 (Telacebec) and co-administration with Q203 sterilizes in vitro cultures in 14 days. Synergy with Q203 occurs via direct inhibition of the cytochrome bd oxidase by HM2-16F. This study shows that amiloride derivatives represent a promising discovery platform for targeting energy generation in drug-resistant tuberculosis. Derivatives of the FDA-approved drug, amiloride, can eliminate drug-resistant Mycobacterium tuberculosis in vitro by interfering with bacterial energy conservation.
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Affiliation(s)
- Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Otago, Dunedin, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Natalie Waller
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara Adolph
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Laura Keighley
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Zhi Shean Tee
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Liam K Harold
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Otago, Dunedin, New Zealand
| | - Ayana Menorca
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Richard S Bujaroski
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Benjamin J Buckley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | | | - Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Otago, Dunedin, New Zealand
| | - Kyu Y Rhee
- Weill Department of Medicine, Weill Cornell Medical College, New York, NY, USA
| | | | - Kurt Krause
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Otago, Dunedin, New Zealand
| | - Laura Preiss
- Department of Structural Biology, Max-Planck Institute of Biophysics, Frankfurt am Main, Germany.,Octapharma Biopharmaceuticals GmbH, Heidelberg, Germany
| | - Julian D Langer
- Department of Molecular Membrane Biology, Max-Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Thomas Meier
- Department of Life Sciences, Imperial College London, London, UK.,Private University in the Principality of Liechtenstein, Triesen, Liechtenstein
| | - Erik J Hasenoehrl
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael J Kelso
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia. .,Illawarra Health and Medical Research Institute, Wollongong, Australia.
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Otago, Dunedin, New Zealand.
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46
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Heusser SA, Borg CB, Colding JM, Pless SA. Conformational decoupling in acid-sensing ion channels uncovers mechanism and stoichiometry of PcTx1-mediated inhibition. eLife 2022; 11:73384. [PMID: 35156612 PMCID: PMC8871370 DOI: 10.7554/elife.73384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 02/11/2022] [Indexed: 01/10/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are trimeric proton-gated cation channels involved in fast synaptic transmission. Pharmacological inhibition of ASIC1a reduces neurotoxicity and stroke infarct volumes, with the cysteine knot toxin psalmotoxin-1 (PcTx1) being one of the most potent and selective inhibitors. PcTx1 binds at the subunit interface in the extracellular domain (ECD), but the mechanism and conformational consequences of the interaction, as well as the number of toxin molecules required for inhibition, remain unknown. Here, we use voltage-clamp fluorometry and subunit concatenation to decipher the mechanism and stoichiometry of PcTx1 inhibition of ASIC1a. Besides the known inhibitory binding mode, we propose PcTx1 to have at least two additional binding modes that are decoupled from the pore. One of these modes induces a long-lived ECD conformation that reduces the activity of an endogenous neuropeptide. This long-lived conformational state is proton-dependent and can be destabilized by a mutation that decreases PcTx1 sensitivity. Lastly, the use of concatemeric channel constructs reveals that disruption of a single PcTx1 binding site is sufficient to destabilize the toxin-induced conformation, while functional inhibition is not impaired until two or more binding sites are mutated. Together, our work provides insight into the mechanism of PcTx1 inhibition of ASICs and uncovers a prolonged conformational change with possible pharmacological implications.
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Affiliation(s)
- Stephanie A Heusser
- Department of Drug Design and Pharmacology, University of Copenhagen, Copehagen, Denmark
| | - Christian B Borg
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Janne M Colding
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Stephan A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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47
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Wang C, Polovitskaya MM, Delgado BD, Jentsch TJ, Long SB. Gating choreography and mechanism of the human proton-activated chloride channel ASOR. SCIENCE ADVANCES 2022; 8:eabm3942. [PMID: 35108041 PMCID: PMC8809534 DOI: 10.1126/sciadv.abm3942] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/08/2021] [Indexed: 05/25/2023]
Abstract
The proton-activated chloride channel ASOR (TMEM206/PAC) permeates anions across cellular membranes in response to acidification, thereby enhancing acid-induced cell death and regulating endocytosis. The molecular mechanisms of pH-dependent control are not understood, in part because structural information for an activated conformation of ASOR is lacking. Here, we reconstitute function from purified protein and present a 3.1-Å-resolution cryo-electron microscopy structure of human ASOR at acidic pH in an activated conformation. The work contextualizes a previous acidic pH structure as a desensitized conformation. Combined with electrophysiological studies and high-resolution structures of resting and desensitized states, the work reveals mechanisms of proton sensing and ion pore gating. Clusters of extracellular acidic residues function as pH sensors and coalesce when protonated. Ensuing conformational changes induce metamorphosis of transmembrane helices to fashion an ion conduction pathway unique to the activated conformation. The studies identify a new paradigm of channel gating in this ubiquitous ion channel.
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Affiliation(s)
- Chongyuan Wang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Maya M. Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, Germany
| | - Bryce D. Delgado
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
- Graduate Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Medicine Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, D-10117 Berlin, Germany
| | - Stephen B. Long
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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48
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Dynamic genetic differentiation drives the widespread structural and functional convergent evolution of snake venom proteinaceous toxins. BMC Biol 2022; 20:4. [PMID: 34996434 PMCID: PMC8742412 DOI: 10.1186/s12915-021-01208-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/06/2021] [Indexed: 12/25/2022] Open
Abstract
Background The explosive radiation and diversification of the advanced snakes (superfamily Colubroidea) was associated with changes in all aspects of the shared venom system. Morphological changes included the partitioning of the mixed ancestral glands into two discrete glands devoted for production of venom or mucous respectively, as well as changes in the location, size and structural elements of the venom-delivering teeth. Evidence also exists for homology among venom gland toxins expressed across the advanced snakes. However, despite the evolutionary novelty of snake venoms, in-depth toxin molecular evolutionary history reconstructions have been mostly limited to those types present in only two front-fanged snake families, Elapidae and Viperidae. To have a broader understanding of toxins shared among extant snakes, here we first sequenced the transcriptomes of eight taxonomically diverse rear-fanged species and four key viperid species and analysed major toxin types shared across the advanced snakes. Results Transcriptomes were constructed for the following families and species: Colubridae - Helicops leopardinus, Heterodon nasicus, Rhabdophis subminiatus; Homalopsidae – Homalopsis buccata; Lamprophiidae - Malpolon monspessulanus, Psammophis schokari, Psammophis subtaeniatus, Rhamphiophis oxyrhynchus; and Viperidae – Bitis atropos, Pseudocerastes urarachnoides, Tropidolaeumus subannulatus, Vipera transcaucasiana. These sequences were combined with those from available databases of other species in order to facilitate a robust reconstruction of the molecular evolutionary history of the key toxin classes present in the venom of the last common ancestor of the advanced snakes, and thus present across the full diversity of colubroid snake venoms. In addition to differential rates of evolution in toxin classes between the snake lineages, these analyses revealed multiple instances of previously unknown instances of structural and functional convergences. Structural convergences included: the evolution of new cysteines to form heteromeric complexes, such as within kunitz peptides (the beta-bungarotoxin trait evolving on at least two occasions) and within SVMP enzymes (the P-IIId trait evolving on at least three occasions); and the C-terminal tail evolving on two separate occasions within the C-type natriuretic peptides, to create structural and functional analogues of the ANP/BNP tailed condition. Also shown was that the de novo evolution of new post-translationally liberated toxin families within the natriuretic peptide gene propeptide region occurred on at least five occasions, with novel functions ranging from induction of hypotension to post-synaptic neurotoxicity. Functional convergences included the following: multiple occasions of SVMP neofunctionalised in procoagulant venoms into activators of the clotting factors prothrombin and Factor X; multiple instances in procoagulant venoms where kunitz peptides were neofunctionalised into inhibitors of the clot destroying enzyme plasmin, thereby prolonging the half-life of the clots formed by the clotting activating enzymatic toxins; and multiple occasions of kunitz peptides neofunctionalised into neurotoxins acting on presynaptic targets, including twice just within Bungarus venoms. Conclusions We found novel convergences in both structural and functional evolution of snake toxins. These results provide a detailed roadmap for future work to elucidate predator–prey evolutionary arms races, ascertain differential clinical pathologies, as well as documenting rich biodiscovery resources for lead compounds in the drug design and discovery pipeline. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01208-9.
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49
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Chen Z, Lin S, Xie T, Lin JM, Canessa CM. A flexible GAS belt responds to pore mutations changing the ion selectivity of proton-gated channels. J Gen Physiol 2022; 154:212811. [PMID: 34766968 PMCID: PMC8594623 DOI: 10.1085/jgp.202112978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/18/2021] [Accepted: 10/18/2021] [Indexed: 11/20/2022] Open
Abstract
Proton-gated ion channels conduct mainly Na+ to induce postsynaptic membrane depolarization. Finding the determinants of ion selectivity requires knowledge of the pore structure in the open conformation, but such information is not yet available. Here, the open conformation of the hASIC1a channel was computationally modeled, and functional effects of pore mutations were analyzed in light of the predicted structures. The open pore structure shows two constrictions of similar diameter formed by the backbone of the GAS belt and, right beneath it, by the side chains of H28 from the reentrant loop. Models of nonselective mutant channels, but not those that maintain ion selectivity, predict enlargement of the GAS belt, suggesting that this motif is quite flexible and that the loss of stabilizing interactions in the central pore leads to changes in size/shape of the belt. Our results are consistent with the "close-fit" mechanism governing selectivity of hASIC1a, wherein the backbone of the GAS substitutes at least part of the hydration shell of a permeant ion to enable crossing the pore constriction.
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Affiliation(s)
- Zhuyuan Chen
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China
| | - Sheng Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Tianze Xie
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Cecilia M Canessa
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China.,Cellular and Molecular Physiology, Yale University, New Haven, CT
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50
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Peverini L, Dunning K, Peralta FA, Grutter T. Photo-isomerizable tweezers to probe ionotropic receptor mechanisms. Curr Opin Pharmacol 2021; 62:109-116. [PMID: 34965483 DOI: 10.1016/j.coph.2021.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/05/2021] [Accepted: 11/18/2021] [Indexed: 12/15/2022]
Abstract
Ligand-gated ion channels (LGIC, also referred to as ionotropic receptors) are important transmembrane proteins that open to allow ions to flow across the membrane and locally modify the membrane potential in response to the binding of a ligand. For more than a decade, a tremendous effort has been carried out in the determination of many LGIC structures in high resolution, leading to an unprecedented molecular description of channel gating. However, it is sometimes difficult to classify experimentally derived structures to their corresponding functional states, and alternative methods may help resolve or refine this issue. In this review, we focus on the application of photo-isomerizable tweezers (PIT) as a powerful strategy to interrogate molecular mechanisms of LGIC while assessing their functionality by electrophysiology.
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Affiliation(s)
- Laurie Peverini
- Unité Récepteurs-Canaux, Institut Pasteur, UMR 3571, CNRS, 75015, Paris, France
| | - Kate Dunning
- CNM Team, Université de Strasbourg, Centre National de La Recherche Scientifique, CAMB UMR 7199, Faculté de Pharmacie, 67401, Illkirch, France
| | - Francisco Andres Peralta
- CNM Team, Université de Strasbourg, Centre National de La Recherche Scientifique, CAMB UMR 7199, Faculté de Pharmacie, 67401, Illkirch, France; University of Strasbourg Institute for Advanced Studies (USIAS), 67000, Strasbourg, France
| | - Thomas Grutter
- CNM Team, Université de Strasbourg, Centre National de La Recherche Scientifique, CAMB UMR 7199, Faculté de Pharmacie, 67401, Illkirch, France; University of Strasbourg Institute for Advanced Studies (USIAS), 67000, Strasbourg, France.
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