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Malak OA, Gluhov GS, Grizel AV, Kudryashova KS, Sokolova OS, Loussouarn G. Voltage-dependent activation in EAG channels follows a ligand-receptor rather than a mechanical-lever mechanism. J Biol Chem 2019; 294:6506-6521. [PMID: 30808709 DOI: 10.1074/jbc.ra119.007626] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/21/2019] [Indexed: 01/08/2023] Open
Abstract
Ether-a-go-go family (EAG) channels play a major role in many physiological processes in humans, including cardiac repolarization and cell proliferation. Cryo-EM structures of two of them, KV10.1 and human ether-a-go-go-related gene (hERG or KV11.1), have revealed an original nondomain-swapped structure, suggesting that the mechanism of voltage-dependent gating of these two channels is quite different from the classical mechanical-lever model. Molecular aspects of hERG voltage-gating have been extensively studied, indicating that the S4-S5 linker (S4-S5L) acts as a ligand binding to the S6 gate (S6 C-terminal part, S6T) and stabilizes it in a closed state. Moreover, the N-terminal extremity of the channel, called N-Cap, has been suggested to interact with S4-S5L to modulate channel voltage-dependent gating, as N-Cap deletion drastically accelerates hERG channel deactivation. In this study, using COS-7 cells, site-directed mutagenesis, electrophysiological measurements, and immunofluorescence confocal microscopy, we addressed whether these two major mechanisms of voltage-dependent gating are conserved in KV10.2 channels. Using cysteine bridges and S4-S5L-mimicking peptides, we show that the ligand/receptor model is conserved in KV10.2, suggesting that this model is a hallmark of EAG channels. Truncation of the N-Cap domain, Per-Arnt-Sim (PAS) domain, or both in KV10.2 abolished the current and altered channel trafficking to the membrane, unlike for the hERG channel in which N-Cap and PAS domain truncations mainly affected channel deactivation. Our results suggest that EAG channels function via a conserved ligand/receptor model of voltage gating, but that the N-Cap and PAS domains have different roles in these channels.
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Affiliation(s)
- Olfat A Malak
- From the INSERM, CNRS, l'Institut du Thorax, Université de Nantes, 44007 Nantes, France
| | - Grigory S Gluhov
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia
| | - Anastasia V Grizel
- the Saint Petersburg State University, Saint Petersburg 199034, Russia, and
| | - Kseniya S Kudryashova
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia.,the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Moscow 117997, Russia
| | - Olga S Sokolova
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia
| | - Gildas Loussouarn
- From the INSERM, CNRS, l'Institut du Thorax, Université de Nantes, 44007 Nantes, France,
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Shenkarev ZO, Karlova MG, Kulbatskii DS, Kirpichnikov MP, Lyukmanova EN, Sokolova OS. Recombinant Production, Reconstruction in Lipid-Protein Nanodiscs, and Electron Microscopy of Full-Length α-Subunit of Human Potassium Channel Kv7.1. BIOCHEMISTRY (MOSCOW) 2018; 83:562-573. [PMID: 29738690 DOI: 10.1134/s0006297918050097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Voltage-gated potassium channel Kv7.1 plays an important role in the excitability of cardiac muscle. The α-subunit of Kv7.1 (KCNQ1) is the main structural element of this channel. Tetramerization of KCNQ1 in the membrane results in formation of an ion channel, which comprises a pore and four voltage-sensing domains. Mutations in the human KCNQ1 gene are one of the major causes of inherited arrhythmias, long QT syndrome in particular. The construct encoding full-length human KCNQ1 protein was synthesized in this work, and an expression system in the Pichia pastoris yeast cells was developed. The membrane fraction of the yeast cells containing the recombinant protein (rKCNQ1) was solubilized with CHAPS detergent. To better mimic the lipid environment of the channel, lipid-protein nanodiscs were formed using solubilized membrane fraction and MSP2N2 protein. The rKCNQ1/nanodisc and rKCNQ1/CHAPS samples were purified using the Rho1D4 tag introduced at the C-terminus of the protein. Protein samples were examined using transmission electron microscopy with negative staining. In both cases, homogeneous rKCNQ1 samples were observed based on image analysis. Statistical analysis of the images of individual protein particles solubilized in the detergent revealed the presence of a tetrameric structure confirming intact subunit assembly. A three-dimensional channel structure reconstructed at 2.5-nm resolution represents a compact density with diameter of the membrane part of ~9 nm and height ~11 nm. Analysis of the images of rKCNQ1 in nanodiscs revealed additional electron density corresponding to the lipid bilayer fragment and the MSP2N2 protein. These results indicate that the nanodiscs facilitate protein isolation, purification, and stabilization in solution and can be used for further structural studies of human Kv7.1.
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Affiliation(s)
- Z O Shenkarev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - M G Karlova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - D S Kulbatskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - M P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - E N Lyukmanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - O S Sokolova
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia.
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Glukhov GS, Popinako AV, Grizel AV, Shaitan KV, Sokolova OS. The structure of a human voltage-gated potassium Kv10.2 channel which lacks a cytoplasmic PAS domain. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916040102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Bagdanoff JT, Xu Y, Dollinger G, Martin E. Effect of Chirality on Common in Vitro Experiments: An Enantiomeric Pair Analysis. J Med Chem 2015. [DOI: 10.1021/acs.jmedchem.5b00552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Jeffrey T. Bagdanoff
- Global
Discovery Chemistry/Oncology and Exploratory Chemistry, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Yongjin Xu
- Global
Discovery Chemistry/Oncology and Exploratory Chemistry, Novartis Institutes for BioMedical Research, 4560 Horton Street, Building 4, Emeryville, California 94608, United States
| | - Gavin Dollinger
- Global
Discovery Chemistry/Oncology and Exploratory Chemistry, Novartis Institutes for BioMedical Research, 4560 Horton Street, Building 4, Emeryville, California 94608, United States
| | - Eric Martin
- Global
Discovery Chemistry/Oncology and Exploratory Chemistry, Novartis Institutes for BioMedical Research, 4560 Horton Street, Building 4, Emeryville, California 94608, United States
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Domain Structure and Conformational Changes in rat KV2.1 ion Channel. J Neuroimmune Pharmacol 2014; 9:727-39. [DOI: 10.1007/s11481-014-9565-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 09/03/2014] [Indexed: 01/26/2023]
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