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Fijalkowski I, Snauwaert V, Van Damme P. Proteins à la carte: riboproteogenomic exploration of bacterial N-terminal proteoform expression. mBio 2024; 15:e0033324. [PMID: 38511928 PMCID: PMC11005335 DOI: 10.1128/mbio.00333-24] [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: 02/03/2024] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
In recent years, it has become evident that the true complexity of bacterial proteomes remains underestimated. Gene annotation tools are known to propagate biases and overlook certain classes of truly expressed proteins, particularly proteoforms-protein isoforms arising from a single gene. Recent (re-)annotation efforts heavily rely on ribosome profiling by providing a direct readout of translation to fully describe bacterial proteomes. In this study, we employ a robust riboproteogenomic pipeline to conduct a systematic census of expressed N-terminal proteoform pairs, representing two isoforms encoded by a single gene raised by annotated and alternative translation initiation, in Salmonella. Intriguingly, conditional-dependent changes in relative utilization of annotated and alternative translation initiation sites (TIS) were observed in several cases. This suggests that TIS selection is subject to regulatory control, adding yet another layer of complexity to our understanding of bacterial proteomes. IMPORTANCE With the emerging theme of genes within genes comprising the existence of alternative open reading frames (ORFs) generated by translation initiation at in-frame start codons, mechanisms that control the relative utilization of annotated and alternative TIS need to be unraveled and our molecular understanding of resulting proteoforms broadened. Utilizing complementary ribosome profiling strategies to map ORF boundaries, we uncovered dual-encoding ORFs generated by in-frame TIS usage in Salmonella. Besides demonstrating that alternative TIS usage may generate proteoforms with different characteristics, such as differential localization and specialized function, quantitative aspects of conditional retapamulin-assisted ribosome profiling (Ribo-RET) translation initiation maps offer unprecedented insights into the relative utilization of annotated and alternative TIS, enabling the exploration of gene regulatory mechanisms that control TIS usage and, consequently, the translation of N-terminal proteoform pairs.
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Affiliation(s)
- Igor Fijalkowski
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Valdes Snauwaert
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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2
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Capuz A, Osien S, Cardon T, Karnoub MA, Aboulouard S, Raffo-Romero A, Duhamel M, Cizkova D, Trerotola M, Devos D, Kobeissy F, Vanden Abeele F, Bonnefond A, Fournier I, Rodet F, Salzet M. Heimdall, an alternative protein issued from a ncRNA related to kappa light chain variable region of immunoglobulins from astrocytes: a new player in neural proteome. Cell Death Dis 2023; 14:526. [PMID: 37587118 PMCID: PMC10432539 DOI: 10.1038/s41419-023-06037-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/18/2023]
Abstract
The dogma "One gene, one protein" is clearly obsolete since cells use alternative splicing and generate multiple transcripts which are translated into protein isoforms, but also use alternative translation initiation sites (TISs) and termination sites on a given transcript. Alternative open reading frames for individual transcripts give proteins originate from the 5'- and 3'-UTR mRNA regions, frameshifts of mRNA ORFs or from non-coding RNAs. Longtime considered as non-coding, recent in-silico translation prediction methods enriched the protein databases allowing the identification of new target structures that have not been identified previously. To gain insight into the role of these newly identified alternative proteins in the regulation of cellular functions, it is crucial to assess their dynamic modulation within a framework of altered physiological modifications such as experimental spinal cord injury (SCI). Here, we carried out a longitudinal proteomic study on rat SCI from 12 h to 10 days. Based on the alternative protein predictions, it was possible to identify a plethora of newly predicted protein hits. Among these proteins, some presented a special interest due to high homology with variable chain regions of immunoglobulins. We focus our interest on the one related to Kappa variable light chains which is similarly highly produced by B cells in the Bence jones disease, but here expressed in astrocytes. This protein, name Heimdall is an Intrinsically disordered protein which is secreted under inflammatory conditions. Immunoprecipitation experiments showed that the Heimdall interactome contained proteins related to astrocyte fate keepers such as "NOTCH1, EPHA3, IPO13" as well as membrane receptor protein including "CHRNA9; TGFBR, EPHB6, and TRAM". However, when Heimdall protein was neutralized utilizing a specific antibody or its gene knocked out by CRISPR-Cas9, sprouting elongations were observed in the corresponding astrocytes. Interestingly, depolarization assays and intracellular calcium measurements in Heimdall KO, established a depolarization effect on astrocyte membranes KO cells were more likely that the one found in neuroprogenitors. Proteomic analyses performed under injury conditions or under lipopolysaccharides (LPS) stimulation, revealed the expression of neuronal factors, stem cell proteins, proliferation, and neurogenesis of astrocyte convertor factors such as EPHA4, NOTCH2, SLIT3, SEMA3F, suggesting a role of Heimdall could regulate astrocytic fate. Taken together, Heimdall could be a novel member of the gatekeeping astrocyte-to-neuroprogenitor conversion factors.
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Affiliation(s)
- Alice Capuz
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Sylvain Osien
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Tristan Cardon
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Mélodie Anne Karnoub
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Soulaimane Aboulouard
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Antonella Raffo-Romero
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Marie Duhamel
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
| | - Dasa Cizkova
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 10, Bratislava, Slovakia
- Centre for Experimental and Clinical Regenerative Medicine, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovakia
| | - Marco Trerotola
- Laboratory of Cancer Pathology, Center for Advanced Studies and Technology (CAST), University 'G. d'Annunzio', Chieti, Italy
- Department of Medical, Oral and Biotechnological Sciences, University 'G. d'Annunzio', Chieti, Italy
| | - David Devos
- Université de Lille, INSERM, U1172, CHU-Lille, Lille Neuroscience Cognition Research Centre, 1 place de Verdun, 59000, Lille, France
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Fabien Vanden Abeele
- Université de Lille, INSERM U1003, Laboratory of Cell Physiology, 59650, Villeneuve d'Ascq, France
| | - Amélie Bonnefond
- Univ. Lille, Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, CHU de Lille, 1 place de Verdun, 59000, Lille, France
| | - Isabelle Fournier
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France
- Institut Universitaire de France, 75005, Paris, France
| | - Franck Rodet
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France.
| | - Michel Salzet
- Univ. Lille, Inserm, U-1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000, Lille, France.
- Institut Universitaire de France, 75005, Paris, France.
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Bogaert A, Fijalkowska D, Staes A, Van de Steene T, Vuylsteke M, Stadler C, Eyckerman S, Spirohn K, Hao T, Calderwood MA, Gevaert K. N-terminal proteoforms may engage in different protein complexes. Life Sci Alliance 2023; 6:e202301972. [PMID: 37316325 PMCID: PMC10267514 DOI: 10.26508/lsa.202301972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/16/2023] Open
Abstract
Alternative translation initiation and alternative splicing may give rise to N-terminal proteoforms, proteins that differ at their N-terminus compared with their canonical counterparts. Such proteoforms can have altered localizations, stabilities, and functions. Although proteoforms generated from splice variants can be engaged in different protein complexes, it remained to be studied to what extent this applies to N-terminal proteoforms. To address this, we mapped the interactomes of several pairs of N-terminal proteoforms and their canonical counterparts. First, we generated a catalogue of N-terminal proteoforms found in the HEK293T cellular cytosol from which 22 pairs were selected for interactome profiling. In addition, we provide evidence for the expression of several N-terminal proteoforms, identified in our catalogue, across different human tissues, as well as tissue-specific expression, highlighting their biological relevance. Protein-protein interaction profiling revealed that the overlap of the interactomes for both proteoforms is generally high, showing their functional relation. We also showed that N-terminal proteoforms can be engaged in new interactions and/or lose several interactions compared with their canonical counterparts, thus further expanding the functional diversity of proteomes.
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Affiliation(s)
- Annelies Bogaert
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Daria Fijalkowska
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - An Staes
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Tessa Van de Steene
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | | | - Charlotte Stadler
- Department of Protein Science, KTH Royal Institute of Technology and Science for Life Laboratories, Stockholm, Sweden
| | - Sven Eyckerman
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Kerstin Spirohn
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Tong Hao
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Michael A Calderwood
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
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4
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A decoupled Virotrap approach to study the interactomes of N-terminal proteoforms. Methods Enzymol 2023; 684:253-287. [DOI: 10.1016/bs.mie.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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5
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Bechard E, Bride J, Le Guennec JY, Brette F, Demion M. TREK-1 in the heart: Potential physiological and pathophysiological roles. Front Physiol 2022; 13:1095102. [PMID: 36620226 PMCID: PMC9815770 DOI: 10.3389/fphys.2022.1095102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
The TREK-1 channel belongs to the TREK subfamily of two-pore domains channels that are activated by stretch and polyunsaturated fatty acids and inactivated by Protein Kinase A phosphorylation. The activation of this potassium channel must induce a hyperpolarization of the resting membrane potential and a shortening of the action potential duration in neurons and cardiac cells, two phenomena being beneficial for these tissues in pathological situations like ischemia-reperfusion. Surprisingly, the physiological role of TREK-1 in cardiac function has never been thoroughly investigated, very likely because of the lack of a specific inhibitor. However, possible roles have been unraveled in pathological situations such as atrial fibrillation worsened by heart failure, right ventricular outflow tract tachycardia or pulmonary arterial hypertension. The inhomogeneous distribution of TREK-1 channel within the heart reinforces the idea that this stretch-activated potassium channel might play a role in cardiac areas where the mechanical constraints are important and need a particular protection afforded by TREK-1. Consequently, the main purpose of this mini review is to discuss the possible role played by TREK -1 in physiological and pathophysiological conditions and its potential role in mechano-electrical feedback. Improved understanding of the role of TREK-1 in the heart may help the development of promising treatments for challenging cardiac diseases.
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Benarroch E. What Is the Role of 2-Pore Domain Potassium Channels (K2P) in Pain? Neurology 2022; 99:516-521. [PMID: 36123135 DOI: 10.1212/wnl.0000000000201197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 11/15/2022] Open
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Fernández E, Bogaert A, Timmerman E, Staes A, Impens F, Gevaert K. A Strong Cation Exchange Chromatography Protocol for Examining N-Terminal Proteoforms. Methods Mol Biol 2022; 2477:293-309. [PMID: 35524124 DOI: 10.1007/978-1-0716-2257-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Especially in eukaryotes, the N-terminal acetylation status of a protein reveals translation initiation sites and substrate specificities and activities of N-terminal acetyltransferases (NATs). Here, we discuss a bottom-up proteomics protocol for the enrichment of N-terminal peptides via strong cation exchange chromatography. This protocol is based on depleting internal tryptic peptides from proteome digests through their retention on strong cation exchangers, leaving N-terminally acetylated/blocked peptides enriched among the nonretained peptides. As such, one can identify novel N-terminal proteoforms and quantify the degree of N-terminal protein acetylation.
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Affiliation(s)
- Esperanza Fernández
- VIB Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Annelies Bogaert
- VIB Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Evy Timmerman
- VIB Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Proteomics Core, Ghent, Belgium
| | - An Staes
- VIB Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Proteomics Core, Ghent, Belgium
| | - Francis Impens
- VIB Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Proteomics Core, Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, Ghent, Belgium.
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium.
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Two-Pore-Domain Potassium (K 2P-) Channels: Cardiac Expression Patterns and Disease-Specific Remodelling Processes. Cells 2021; 10:cells10112914. [PMID: 34831137 PMCID: PMC8616229 DOI: 10.3390/cells10112914] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/23/2022] Open
Abstract
Two-pore-domain potassium (K2P-) channels conduct outward K+ currents that maintain the resting membrane potential and modulate action potential repolarization. Members of the K2P channel family are widely expressed among different human cell types and organs where they were shown to regulate important physiological processes. Their functional activity is controlled by a broad variety of different stimuli, like pH level, temperature, and mechanical stress but also by the presence of lipids or pharmacological agents. In patients suffering from cardiovascular diseases, alterations in K2P-channel expression and function have been observed, suggesting functional significance and a potential therapeutic role of these ion channels. For example, upregulation of atrial specific K2P3.1 (TASK-1) currents in atrial fibrillation (AF) patients was shown to contribute to atrial action potential duration shortening, a key feature of AF-associated atrial electrical remodelling. Therefore, targeting K2P3.1 (TASK-1) channels might constitute an intriguing strategy for AF treatment. Further, mechanoactive K2P2.1 (TREK-1) currents have been implicated in the development of cardiac hypertrophy, cardiac fibrosis and heart failure. Cardiovascular expression of other K2P channels has been described, functional evidence in cardiac tissue however remains sparse. In the present review, expression, function, and regulation of cardiovascular K2P channels are summarized and compared among different species. Remodelling patterns, observed in disease models are discussed and compared to findings from clinical patients to assess the therapeutic potential of K2P channels.
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Lengyel M, Enyedi P, Czirják G. Negative Influence by the Force: Mechanically Induced Hyperpolarization via K 2P Background Potassium Channels. Int J Mol Sci 2021; 22:ijms22169062. [PMID: 34445768 PMCID: PMC8396510 DOI: 10.3390/ijms22169062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
The two-pore domain K2P subunits form background (leak) potassium channels, which are characterized by constitutive, although not necessarily constant activity, at all membrane potential values. Among the fifteen pore-forming K2P subunits encoded by the KCNK genes, the three members of the TREK subfamily, TREK-1, TREK-2, and TRAAK are mechanosensitive ion channels. Mechanically induced opening of these channels generally results in outward K+ current under physiological conditions, with consequent hyperpolarization and inhibition of membrane potential-dependent cellular functions. In the past decade, great advances have been made in the investigation of the molecular determinants of mechanosensation, and members of the TREK subfamily have emerged among the best-understood examples of mammalian ion channels directly influenced by the tension of the phospholipid bilayer. In parallel, the crucial contribution of mechano-gated TREK channels to the regulation of membrane potential in several cell types has been reported. In this review, we summarize the general principles underlying the mechanical activation of K2P channels, and focus on the physiological roles of mechanically induced hyperpolarization.
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10
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Walsh Y, Leach M, Veale EL, Mathie A. Block of TREK and TRESK K2P channels by lamotrigine and two derivatives sipatrigine and CEN-092. Biochem Biophys Rep 2021; 26:101021. [PMID: 34041373 PMCID: PMC8144350 DOI: 10.1016/j.bbrep.2021.101021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 11/30/2022] Open
Abstract
TREK and TRESK K2P channels are widely expressed in the nervous system, particularly in sensory neurons, where they regulate neuronal excitability. In this study, using whole-cell patch-clamp electrophysiology, we characterise the inhibitory effect of the anticonvulsant lamotrigine and two derivatives, sipatrigine and 3,5-diamino-6-(3,5-bistrifluoromethylphenyl)-1,2,4-triazine (CEN-092) on these channels. Sipatrigine was found to be a more effective inhibitor than lamotrigine of TREK-1, TREK-2 and TRESK channels. Sipatrigine was slightly more potent on TREK-1 channels (EC50 = 16 μM) than TRESK (EC50 = 34 μM) whereas lamotrigine was equally effective on TREK-1 and TRESK. Sipatrigine was less effective on a short isoform of TREK-2, suggesting the N terminus of the channel is important for both inhibition and subsequent over-recovery. Inhibition of TREK-1 and TREK-2 channels by sipatrigine was reduced by mutation of a leucine residue associated with the norfluoxetine binding site on these channels (L289A and L320A on TREK-1 and TREK-2, respectively) but these did not affect inhibition by lamotrigine. Inhibition of TRESK by sipatrigine and lamotrigine was attenuated by mutation of bulky phenylalanine residues (F145A and F352A) in the inner pore helix. However, phosphorylation mutations did not alter the effect of sipatrigine. CEN-092 was a more effective inhibitor of TRESK channels than TREK-1 channels. It is concluded that lamotrigine, sipatrigine and CEN-092 are all inhibitors of TREK and TRESK channels but do not greatly discriminate between them. The actions of these compounds may contribute to their current and potential use in the treatment of pain and depression. Lamotrigine blocks TREK and TRESK potassium channels at clinical concentrations. Sipatrigine is more effective than lamotrigine at blocking TREK and TRESK channels. Mutation of norfluoxetine binding site on TREK channels attenuates sipatrigine block. Residues in the inner pore region of TRESK channels regulate sipatrigine block. The novel lamotrigine derivative, CEN-092, blocks TRESK channels.
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Affiliation(s)
- Yvonne Walsh
- Medway School of Pharmacy, University of Kent and University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
- University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
| | - Michael Leach
- University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
| | - Emma L. Veale
- Medway School of Pharmacy, University of Kent and University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent and University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
- School of Engineering, Arts, Science and Technology, University of Suffolk, Waterfront Building, Neptune Quay, Ipswich, IP4 1QJ, UK
- Corresponding author.Medway School of Pharmacy, University of Kent and University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK.
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Abstract
Two-pore domain potassium channels are formed by subunits that each contain two pore-loops moieties. Whether the channels are expressed in yeast or the human central nervous system, two subunits come together to form a single potassium selective pore. TOK1, the first two-domain channel was cloned from Saccharomyces cerevisiae in 1995 and soon thereafter, 15 distinct K2P subunits were identified in the human genome. The human K2P channels are stratified into six K2P subfamilies based on sequence as well as physiological or pharmacological similarities. Functional K2P channels pass background (or "leak") K+ currents that shape the membrane potential and excitability of cells in a broad range of tissues. In the years since they were first described, classical functional assays, latterly coupled with state-of-the-art structural and computational studies have revealed the mechanistic basis of K2P channel gating in response to specific physicochemical or pharmacological stimuli. The growing appreciation that K2P channels can play a pivotal role in the pathophysiology of a growing spectrum of diseases makes a compelling case for K2P channels as targets for drug discovery. Here, we summarize recent advances in unraveling the structure, function, and pharmacology of the K2P channels.
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Affiliation(s)
- Jordie M Kamuene
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Yu Xu
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA.
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Recovery of Human Embryonic Stem Cells-Derived Neural Progenitors Exposed to Hypoxic-Ischemic-Reperfusion Injury by Indirect Exposure to Wharton’s Jelly Mesenchymal Stem Cells Through Phosphatidyl-inositol-3-Kinase Pathway. Cell Mol Neurobiol 2020; 42:1167-1188. [DOI: 10.1007/s10571-020-01007-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/11/2020] [Indexed: 12/13/2022]
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Abstract
INTRODUCTION The N-terminus of a protein can encode several protein features, including its half-live and its localization. As the proteomics field remains dominated by bottom-up approaches and as N-terminal peptides only account for a fraction of all analyzable peptides, there is a need for their enrichment prior to analysis. COFRADIC, TAILS, and the subtiligase method were among the first N-terminomics methods developed, and several variants and novel methods were introduced that often reduce processing time and/or the amount of material required. AREAS COVERED We present an overview of how the field of N-terminomics developed, including a discussion of the founding methods, several updates made to these and introduce newer methods such as TMPP-labeling, biotin-based methods besides some necessary improvements in data analysis. EXPERT OPINION N-terminomic methods remain being used and improved methods are published however, more efficient use of contemporary mass spectrometers, promising data-independent approaches, and mass spectrometry-free single peptide or protein sequences may threat the N-terminomics field.
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Affiliation(s)
- Annelies Bogaert
- VIB Center for Medical Biotechnology , Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University , Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology , Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University , Ghent, Belgium
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Clinical Importance of the Human Umbilical Artery Potassium Channels. Cells 2020; 9:cells9091956. [PMID: 32854241 PMCID: PMC7565333 DOI: 10.3390/cells9091956] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Potassium (K+) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K+ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K+ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K+ channels described in SMCs: voltage-dependent K+ (KV) channels, calcium-activated K+ (KCa) channels, inward rectifier K+ (Kir) channels, and 2-pore domain K+ (K2P) channels. Due to the fundamental role of K+ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K+ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K+ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.
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15
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Verkest C, Häfner S, Ávalos Prado P, Baron A, Sandoz G. Migraine and Two-Pore-Domain Potassium Channels. Neuroscientist 2020; 27:268-284. [PMID: 32715910 DOI: 10.1177/1073858420940949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Migraine is a common, disabling neurological disorder with a genetic, environmental, and hormonal component with an annual prevalence estimated at ~15%. It is characterized by attacks of severe, usually unilateral and throbbing headache, and can be accompanied by nausea, vomiting, and photophobia. Migraine is clinically divided into two main subtypes: migraine with aura, when it is preceded by transient neurological disturbances due to cortical spreading depression (CSD), and migraine without aura. Activation and sensitization of trigeminal sensory neurons, leading to the release of pro-inflammatory peptides, is likely a key component in headache pain initiation and transmission in migraine. In the present review, we will focus on the function of two-pore-domain potassium (K2P) channels, which control trigeminal sensory neuron excitability and their potential interest for developing new drugs to treat migraine.
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Affiliation(s)
- Clément Verkest
- CNRS, INSERM, iBV, Université Cote d'Azur, Nice, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics Nice, France.,Université Cote d'Azur, CNRS, INSERM, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Stephanie Häfner
- CNRS, INSERM, iBV, Université Cote d'Azur, Nice, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics Nice, France
| | - Pablo Ávalos Prado
- CNRS, INSERM, iBV, Université Cote d'Azur, Nice, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics Nice, France
| | - Anne Baron
- Laboratories of Excellence, Ion Channel Science and Therapeutics Nice, France.,Université Cote d'Azur, CNRS, INSERM, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Guillaume Sandoz
- CNRS, INSERM, iBV, Université Cote d'Azur, Nice, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics Nice, France
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16
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Mathie A, Veale EL, Cunningham KP, Holden RG, Wright PD. Two-Pore Domain Potassium Channels as Drug Targets: Anesthesia and Beyond. Annu Rev Pharmacol Toxicol 2020; 61:401-420. [PMID: 32679007 DOI: 10.1146/annurev-pharmtox-030920-111536] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-pore domain potassium (K2P) channels stabilize the resting membrane potential of both excitable and nonexcitable cells and, as such, are important regulators of cell activity. There are many conditions where pharmacological regulation of K2P channel activity would be of therapeutic benefit, including, but not limited to, atrial fibrillation, respiratory depression, pulmonary hypertension, neuropathic pain, migraine, depression, and some forms of cancer. Up until now, few if any selective pharmacological regulators of K2P channels have been available. However, recent publications of solved structures with small-molecule activators and inhibitors bound to TREK-1, TREK-2, and TASK-1 K2P channels have given insight into the pharmacophore requirements for compound binding to these sites. Together with the increasing availability of a number of novel, active, small-molecule compounds from K2P channel screening programs, these advances have opened up the possibility of rational activator and inhibitor design to selectively target K2P channels.
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Affiliation(s)
- Alistair Mathie
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Emma L Veale
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Kevin P Cunningham
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Robyn G Holden
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
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17
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Wiedmann F, Rinné S, Donner B, Decher N, Katus HA, Schmidt C. Mechanosensitive TREK-1 two-pore-domain potassium (K 2P) channels in the cardiovascular system. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 159:126-135. [PMID: 32553901 DOI: 10.1016/j.pbiomolbio.2020.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/01/2020] [Accepted: 05/11/2020] [Indexed: 12/12/2022]
Abstract
TWIK-related K+ channel (TREK-1) two-pore-domain potassium (K2P) channels mediate background potassium currents and regulate cellular excitability in many different types of cells. Their functional activity is controlled by a broad variety of different physiological stimuli, such as temperature, extracellular or intracellular pH, lipids and mechanical stress. By linking cellular excitability to mechanical stress, TREK-1 currents might be important to mediate parts of the mechanoelectrical feedback described in the heart. Furthermore, TREK-1 currents might contribute to the dysregulation of excitability in the heart in pathophysiological situations, such as those caused by abnormal stretch or ischaemia-associated cell swelling, thereby contributing to arrhythmogenesis. In this review, we focus on the functional role of TREK-1 in the heart and its putative contribution to cardiac mechanoelectrical coupling. Its cardiac expression among different species is discussed, alongside with functional evidence for TREK-1 currents in cardiomyocytes. In addition, evidence for the involvement of TREK-1 currents in different cardiac arrhythmias, such as atrial fibrillation or ventricular tachycardia, is summarized. Furthermore, the role of TREK-1 and its interaction partners in the regulation of the cardiac heart rate is reviewed. Finally, we focus on the significance of TREK-1 in the development of cardiac hypertrophy, cardiac fibrosis and heart failure.
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Affiliation(s)
- Felix Wiedmann
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - Philipps-University Marburg, Marburg, Germany
| | - Birgit Donner
- Pediatric Cardiology, University Children's Hospital Basel (UKBB), University of Basel, Basel, Switzerland
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - Philipps-University Marburg, Marburg, Germany
| | - Hugo A Katus
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Constanze Schmidt
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany.
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18
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Translating Translation to Mechanisms of Cardiac Hypertrophy. J Cardiovasc Dev Dis 2020; 7:jcdd7010009. [PMID: 32164190 PMCID: PMC7151157 DOI: 10.3390/jcdd7010009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/18/2022] Open
Abstract
Cardiac hypertrophy in response to chronic pathological stress is a common feature occurring with many forms of heart disease. This pathological hypertrophic growth increases the risk for arrhythmias and subsequent heart failure. While several factors promoting cardiac hypertrophy are known, the molecular mechanisms governing the progression to heart failure are incompletely understood. Recent studies on altered translational regulation during pathological cardiac hypertrophy are contributing to our understanding of disease progression. In this brief review, we describe how the translational machinery is modulated for enhanced global and transcript selective protein synthesis, and how alternative modes of translation contribute to the disease state. Attempts at controlling translational output through targeting of mTOR and its regulatory components are detailed, as well as recently emerging targets for pre-clinical investigation.
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19
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Bogaert A, Fernandez E, Gevaert K. N-Terminal Proteoforms in Human Disease. Trends Biochem Sci 2020; 45:308-320. [PMID: 32001092 DOI: 10.1016/j.tibs.2019.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/06/2019] [Accepted: 12/31/2019] [Indexed: 12/20/2022]
Abstract
The collection of chemically different protein variants, or proteoforms, by far exceeds the number of protein-coding genes in the human genome. Major contributors are alternative splicing and protein modifications. In this review, we focus on those proteoforms that differ at their N termini with a molecular link to disease. We describe the main underlying mechanisms that give rise to such N-terminal proteoforms, these being splicing, initiation of protein translation, and protein modifications. Given their role in several human diseases, it is becoming increasingly clear that several of these N-terminal proteoforms may have potential as therapeutic interventions and/or for diagnosing and prognosing their associated disease.
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Affiliation(s)
- Annelies Bogaert
- VIB Center for Medical Biotechnology, VIB, B-9000 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, B-9000 Ghent, Belgium
| | - Esperanza Fernandez
- VIB Center for Medical Biotechnology, VIB, B-9000 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, B-9000 Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, VIB, B-9000 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, B-9000 Ghent, Belgium.
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20
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Pattison LA, Callejo G, St John Smith E. Evolution of acid nociception: ion channels and receptors for detecting acid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190291. [PMID: 31544616 PMCID: PMC6790391 DOI: 10.1098/rstb.2019.0291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2019] [Indexed: 12/13/2022] Open
Abstract
Nociceptors, i.e. sensory neurons tuned to detect noxious stimuli, are found in numerous phyla of the Animalia kingdom and are often polymodal, responding to a variety of stimuli, e.g. heat, cold, pressure and chemicals, such as acid. Owing to the ability of protons to have a profound effect on ionic homeostasis and damage macromolecular structures, it is no wonder that the ability to detect acid is conserved across many species. To detect changes in pH, nociceptors are equipped with an assortment of different acid sensors, some of which can detect mild changes in pH, such as the acid-sensing ion channels, proton-sensing G protein-coupled receptors and several two-pore potassium channels, whereas others, such as the transient receptor potential vanilloid 1 ion channel, require larger shifts in pH. This review will discuss the evolution of acid sensation and the different mechanisms by which nociceptors can detect acid. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
| | | | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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21
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Wright PD, McCoull D, Walsh Y, Large JM, Hadrys BW, Gaurilcikaite E, Byrom L, Veale EL, Jerman J, Mathie A. Pranlukast is a novel small molecule activator of the two-pore domain potassium channel TREK2. Biochem Biophys Res Commun 2019; 520:35-40. [DOI: 10.1016/j.bbrc.2019.09.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/21/2019] [Indexed: 11/29/2022]
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22
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N-Glycosylation of TREK-1/hK 2P2.1 Two-Pore-Domain Potassium (K 2P) Channels. Int J Mol Sci 2019; 20:ijms20205193. [PMID: 31635148 PMCID: PMC6829520 DOI: 10.3390/ijms20205193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 10/15/2019] [Accepted: 10/18/2019] [Indexed: 01/11/2023] Open
Abstract
Mechanosensitive hTREK-1 two-pore-domain potassium (hK2P2.1) channels give rise to background currents that control cellular excitability. Recently, TREK-1 currents have been linked to the regulation of cardiac rhythm as well as to hypertrophy and fibrosis. Even though the pharmacological and biophysical characteristics of hTREK-1 channels have been widely studied, relatively little is known about their posttranslational modifications. This study aimed to evaluate whether hTREK-1 channels are N-glycosylated and whether glycosylation may affect channel functionality. Following pharmacological inhibition of N-glycosylation, enzymatic digestion or mutagenesis, immunoblots of Xenopus laevis oocytes and HEK-293T cell lysates were used to assess electrophoretic mobility. Two-electrode voltage clamp measurements were employed to study channel function. TREK-1 channel subunits undergo N-glycosylation at asparagine residues 110 and 134. The presence of sugar moieties at these two sites increases channel function. Detection of glycosylation-deficient mutant channels in surface fractions and recordings of macroscopic potassium currents mediated by these subunits demonstrated that nonglycosylated hTREK-1 channel subunits are able to reach the cell surface in general but with seemingly reduced efficiency compared to glycosylated subunits. These findings extend our understanding of the regulation of hTREK-1 currents by posttranslational modifications and provide novel insights into how altered ion channel glycosylation may promote arrhythmogenesis.
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23
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Staudacher I, Seehausen S, Illg C, Lugenbiel P, Schweizer PA, Katus HA, Thomas D. Cardiac K2P13.1 (THIK-1) two-pore-domain K+ channels: Pharmacological regulation and remodeling in atrial fibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 144:128-138. [DOI: 10.1016/j.pbiomolbio.2018.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/28/2018] [Accepted: 06/25/2018] [Indexed: 01/30/2023]
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24
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Lv J, Liang Y, Zhang S, Lan Q, Xu Z, Wu X, Kang L, Ren J, Cao Y, Wu T, Lin KL, Yung KKL, Cao X, Pang J, Zhou P. DCPIB, an Inhibitor of Volume-Regulated Anion Channels, Distinctly Modulates K2P Channels. ACS Chem Neurosci 2019; 10:2786-2793. [PMID: 30935201 DOI: 10.1021/acschemneuro.9b00010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
K2P potassium channels stabilize the resting membrane potential in nearly all cells and have been implicated in several neuronal, cardiovascular, and immune diseases. DCPIB, a known specific and potent inhibitor of volume-regulated anion channels (VRAC), has been reported to activate TREK1 and TREK2 in astrocytes and in vitro recently. In the present study, we demonstrated DCPIB also voltage dependently activated TRAAK besides TREK1/TREK2, showing DCPIB activated all TREK subfamily members. In contrast, the compound potently inhibited several other K2P channels with no voltage dependence, including TRESK, TASK1, and TASK3. DCPIB displayed superior selectivity toward TRESK with an IC50 of 0.14 μM, demonstrating at least 100-fold higher affinity over TREK1/TRAAK channels. Furthermore, the impaired ion selectivity filter region greatly impaired the activating effect of DCPIB on TREK1 but not the inhibitory effect of DCPIB on TRESK. This indicates distinct molecular determinants underlying the effect of DCPIB on TREK1 or TRESK channels. Our results showed that DCPIB played diverse effects on K2P channels and could be a useful tool for further investigating structure-function studies of K2P channels.
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Affiliation(s)
- Jinyan Lv
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yemei Liang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shiqing Zhang
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, China
| | - Qunsheng Lan
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ziwei Xu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
- Key Laboratory of Mental Health of the Ministry of Education, Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Xiaoyan Wu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Lijun Kang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jing Ren
- Key Laboratory of Mental Health of the Ministry of Education, Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ying Cao
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ting Wu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Ka Li Lin
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, China
| | - Ken Kin Lam Yung
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, China
| | - Xiong Cao
- Key Laboratory of Mental Health of the Ministry of Education, Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jianxin Pang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Pingzheng Zhou
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
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25
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Pineda RH, Hypolite J, Lee S, Carrasco A, Iguchi N, Meacham RB, Malykhina AP. Altered detrusor contractility and voiding patterns in mice lacking the mechanosensitive TREK-1 channel. BMC Urol 2019; 19:40. [PMID: 31113422 PMCID: PMC6528348 DOI: 10.1186/s12894-019-0475-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/13/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previously published results from our laboratory identified a mechano-gated two-pore domain potassium channel, TREK-1, as a main mechanosensor in the smooth muscle of the human urinary bladder. One of the limitations of in vitro experiments on isolated human detrusor included inability to evaluate in vivo effects of TREK-1 on voiding function, as the channel is also expressed in the nervous system, and may modulate micturition via neural pathways. Therefore, in the present study, we aimed to assess the role of TREK-1 channel in bladder function and voiding patterns in vivo by using TREK-1 knockout (KO) mice. METHODS Adult C57BL/6 J wild-type (WT, N = 32) and TREK-1 KO (N = 33) mice were used in this study. The overall phenotype and bladder function were evaluated by gene and protein expression of TREK-1 channel, in vitro contractile experiments using detrusor strips in response to stretch and pharmacological stimuli, and cystometry in unanesthetized animals. RESULTS TREK-1 KO animals had an elevated basal muscle tone and enhanced spontaneous activity in the detrusor without detectable changes in bladder morphology/histology. Stretch applied to isolated detrusor strips increased the amplitude of spontaneous contractions by 109% in the TREK-1 KO group in contrast to a 61% increase in WT mice (p ≤ 0.05 to respective baseline for each group). The detrusor strips from TREK-1 KO mice also generated more contractile force in response to electric field stimulation and high potassium concentration in comparison to WT group (p ≤ 0.05 for both tests). However, cystometric recordings from TREK-1 KO mice revealed a significant increase in the duration of the intermicturition interval, enhanced bladder capacity and increased number of non-voiding contractions in comparison to WT mice. CONCLUSIONS Our results provide evidence that global down-regulation of TREK-1 channels has dual effects on detrusor contractility and micturition patterns in vivo. The observed differences are likely due to expression of TREK-1 channel not only in detrusor myocytes but also in afferent and efferent neural pathways involved in regulation of micturition which may underly the "mixed" voiding phenotype in TREK-1 KO mice.
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Affiliation(s)
- Ricardo H Pineda
- Division of Urology, Department of Surgery, University of Colorado Denver,Anschutz Medical Campus, 12700 E 19th Ave, M/S C317, Aurora, CO, 80045, USA
| | - Joseph Hypolite
- Division of Urology, Department of Surgery, University of Colorado Denver,Anschutz Medical Campus, 12700 E 19th Ave, M/S C317, Aurora, CO, 80045, USA
| | - Sanghee Lee
- Department of Urology, University of California San Diego, 3855 Health Science Drive, Room 4345, Bay 4LL, La Jolla, CA, 92093, USA
| | - Alonso Carrasco
- Children's Mercy Hospital, 2401 Gillham Rd, Kansas City, MO, 64108, USA
| | - Nao Iguchi
- Division of Urology, Department of Surgery, University of Colorado Denver,Anschutz Medical Campus, 12700 E 19th Ave, M/S C317, Aurora, CO, 80045, USA
| | - Randall B Meacham
- Division of Urology, Department of Surgery, University of Colorado Denver, Academic Office One Bldg., Rm 5602, 12631 East 17th Ave., M/S C319, Aurora, CO, 80045, USA
| | - Anna P Malykhina
- Division of Urology, Department of Surgery, University of Colorado Denver,Anschutz Medical Campus, 12700 E 19th Ave, M/S C317, Aurora, CO, 80045, USA.
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26
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Tarasov MV, Kotova PD, Bystrova MF, Kabanova NV, Sysoeva VY, Kolesnikov SS. Arachidonic acid hyperpolarizes mesenchymal stromal cells from the human adipose tissue by stimulating TREK1 K + channels. Channels (Austin) 2019; 13:36-47. [PMID: 30661462 PMCID: PMC6380217 DOI: 10.1080/19336950.2019.1565251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The current knowledge of electrogenesis in mesenchymal stromal cells (MSCs) remains scarce. Earlier, we demonstrated that in MSCs from the human adipose tissue, transduction of certain agonists involved the phosphoinositide cascade. Its pivotal effector PLC generates DAG that can regulate ion channels directly or via its derivatives, including arachidonic acid (AA). Here we showed that AA strongly hyperpolarized MSCs by stimulating instantly activating, outwardly rectifying TEA-insensitive K+ channels. Among AA-regulated K+ channels, K2P channels from the TREK subfamily appeared to be an appropriate target. The expression of K2P channels in MSCs was verified by RT-PCR, which revealed TWIK-1, TREK-1, and TASK-5 transcripts. The TREK-1 inhibitor spadin antagonized the electrogenic action of AA, which was simulated by the channel activator BL 1249. This functional evidence suggested that TREK-1 channels mediated AA-dependent hyperpolarization of MSCs. Being mostly silent at rest, TREK-1 negligibly contributed to the “background” K+ current. The dramatic stimulation of TREK-1 channels by AA indicates their involvement in AA-dependent signaling in MSCs.
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Affiliation(s)
- Michail V Tarasov
- a Department of Molecular Cell Physiology, Institute of Cell Biophysics , Russian Academy of Sciences , Pushchino , Moscow Region , Russia
| | - Polina D Kotova
- a Department of Molecular Cell Physiology, Institute of Cell Biophysics , Russian Academy of Sciences , Pushchino , Moscow Region , Russia
| | - Marina F Bystrova
- a Department of Molecular Cell Physiology, Institute of Cell Biophysics , Russian Academy of Sciences , Pushchino , Moscow Region , Russia
| | - Natalia V Kabanova
- a Department of Molecular Cell Physiology, Institute of Cell Biophysics , Russian Academy of Sciences , Pushchino , Moscow Region , Russia
| | - Veronika Yu Sysoeva
- b Department of Biochemistry and Molecular Medicine, Faculty of Basic Medicine , Lomonosov Moscow State University , Moscow , Russia
| | - Stanislav S Kolesnikov
- a Department of Molecular Cell Physiology, Institute of Cell Biophysics , Russian Academy of Sciences , Pushchino , Moscow Region , Russia
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27
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Sapkota D, Lake AM, Yang W, Yang C, Wesseling H, Guise A, Uncu C, Dalal JS, Kraft AW, Lee JM, Sands MS, Steen JA, Dougherty JD. Cell-Type-Specific Profiling of Alternative Translation Identifies Regulated Protein Isoform Variation in the Mouse Brain. Cell Rep 2019; 26:594-607.e7. [PMID: 30650354 PMCID: PMC6392083 DOI: 10.1016/j.celrep.2018.12.077] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/23/2018] [Accepted: 12/18/2018] [Indexed: 12/27/2022] Open
Abstract
Alternative translation initiation and stop codon readthrough in a few well-studied cases have been shown to allow the same transcript to generate multiple protein variants. Because the brain shows a particularly abundant use of alternative splicing, we sought to study alternative translation in CNS cells. We show that alternative translation is widespread and regulated across brain transcripts. In neural cultures, we identify alternative initiation on hundreds of transcripts, confirm several N-terminal protein variants, and show the modulation of the phenomenon by KCl stimulation. We also detect readthrough in cultures and show differential levels of normal and readthrough versions of AQP4 in gliotic diseases. Finally, we couple translating ribosome affinity purification to ribosome footprinting (TRAP-RF) for cell-type-specific analysis of neuronal and astrocytic translational readthrough in the mouse brain. We demonstrate that this unappreciated mechanism generates numerous and diverse protein isoforms in a cell-type-specific manner in the brain.
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Affiliation(s)
- Darshan Sapkota
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Allison M Lake
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Wei Yang
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chengran Yang
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hendrik Wesseling
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda Guise
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ceren Uncu
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jasbir S Dalal
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew W Kraft
- Departments of Neurology, Radiology, and Biomedical Engineering, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jin-Moo Lee
- Departments of Neurology, Radiology, and Biomedical Engineering, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mark S Sands
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; Deparment of Medicine, Washington University School of Medicine, St. Louis, MO 63112, USA
| | - Judith A Steen
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Joseph D Dougherty
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
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28
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Cloning and characterization of zebrafish K2P13.1 (THIK-1) two-pore-domain K+ channels. J Mol Cell Cardiol 2019; 126:96-104. [DOI: 10.1016/j.yjmcc.2018.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/23/2018] [Accepted: 11/21/2018] [Indexed: 12/28/2022]
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Migraine-Associated TRESK Mutations Increase Neuronal Excitability through Alternative Translation Initiation and Inhibition of TREK. Neuron 2018; 101:232-245.e6. [PMID: 30573346 DOI: 10.1016/j.neuron.2018.11.039] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/03/2018] [Accepted: 11/20/2018] [Indexed: 12/12/2022]
Abstract
It is often unclear why some genetic mutations to a given gene contribute to neurological disorders and others do not. For instance, two mutations have previously been found to produce a dominant negative for TRESK, a two-pore-domain K+ channel implicated in migraine: TRESK-MT, a 2-bp frameshift mutation, and TRESK-C110R. Both mutants inhibit TRESK, but only TRESK-MT increases sensory neuron excitability and is linked to migraine. Here, we identify a new mechanism, termed frameshift mutation-induced alternative translation initiation (fsATI), that may explain why only TRESK-MT is associated with migraine. fsATI leads to the production of a second protein fragment, TRESK-MT2, which co-assembles with and inhibits TREK1 and TREK2, two other two-pore-domain K+ channels, to increase trigeminal sensory neuron excitability, leading to a migraine-like phenotype in rodents. These findings identify TREK1 and TREK2 as potential molecular targets in migraine and suggest that fsATI should be considered as a distinct class of mutations.
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Gada K, Plant LD. Two-pore domain potassium channels: emerging targets for novel analgesic drugs: IUPHAR Review 26. Br J Pharmacol 2018; 176:256-266. [PMID: 30325008 DOI: 10.1111/bph.14518] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/23/2018] [Accepted: 08/18/2018] [Indexed: 01/02/2023] Open
Abstract
Chronic pain is a debilitating and increasingly common medical problem with few effective treatments. In addition to the direct and indirect economic burden of pain syndromes, the concomitant increase in prescriptions for narcotics has contributed to a sharp rise in deaths associated with drug misuse - the 'opioid crisis'. Together, these issues highlight the unmet clinical and social need for a new generation of safe, efficacious analgesics. The detection and transmission of pain stimuli is largely mediated by somatosensory afferent fibres of the dorsal root ganglia. These nociceptive cells express an array of membrane proteins that have received significant attention as attractive targets for new pain medications. Among these, a growing body of evidence supports a role for the two-pore domain potassium (K2P) family of K+ channels. Here, we provide a concise review of the K2P channels, their role in pain biology and their potential as targets for novel analgesic agents.
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Affiliation(s)
- Kirin Gada
- Department of Pharmaceutical Sciences in the School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences in the School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
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31
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Soussia IB, Choveau FS, Blin S, Kim EJ, Feliciangeli S, Chatelain FC, Kang D, Bichet D, Lesage F. Antagonistic Effect of a Cytoplasmic Domain on the Basal Activity of Polymodal Potassium Channels. Front Mol Neurosci 2018; 11:301. [PMID: 30233308 PMCID: PMC6131555 DOI: 10.3389/fnmol.2018.00301] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 08/09/2018] [Indexed: 02/06/2023] Open
Abstract
TREK/TRAAK channels are polymodal K+ channels that convert very diverse stimuli, including bioactive lipids, mechanical stretch and temperature, into electrical signals. The nature of the structural changes that regulate their activity remains an open question. Here, we show that a cytoplasmic domain (the proximal C-ter domain, pCt) exerts antagonistic effects in TREK1 and TRAAK. In basal conditions, pCt favors activity in TREK1 whereas it impairs TRAAK activity. Using the conformation-dependent binding of fluoxetine, we show that TREK1 and TRAAK conformations at rest are different, and under the influence of pCt. Finally, we show that depleting PIP2 in live cells has a more pronounced inhibitory effect on TREK1 than on TRAAK. This differential regulation of TREK1 and TRAAK is related to a previously unrecognized PIP2-binding site (R329, R330, and R331) present within TREK1 pCt, but not in TRAAK pCt. Collectively, these new data point out pCt as a major regulatory domain of these channels and suggest that the binding of PIP2 to the pCt of TREK1 results in the stabilization of the conductive conformation in basal conditions.
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Affiliation(s)
- Ismail Ben Soussia
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Frank S Choveau
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Sandy Blin
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Eun-Jin Kim
- Department of Physiology, College of Medicine, Institute of Health Sciences, Gyeongsang National University, Jinju, South Korea
| | - Sylvain Feliciangeli
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Franck C Chatelain
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Dawon Kang
- Department of Physiology, College of Medicine, Institute of Health Sciences, Gyeongsang National University, Jinju, South Korea
| | - Delphine Bichet
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
| | - Florian Lesage
- Université Côte d'Azur, INSERM, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Labex ICST, Valbonne, France
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32
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Cardiovascular pharmacology of K 2P17.1 (TASK-4, TALK-2) two-pore-domain K + channels. Naunyn Schmiedebergs Arch Pharmacol 2018; 391:1119-1131. [PMID: 30008082 DOI: 10.1007/s00210-018-1535-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 07/06/2018] [Indexed: 10/28/2022]
Abstract
K2P17.1 (TASK-4, TALK-2) potassium channels are expressed in the heart and represent potential targets for pharmacological management of atrial and ventricular arrhythmias. Reduced K2P17.1 expression was found in atria and ventricles of heart failure (HF) patients. Modulation of K2P17.1 currents by antiarrhythmic compounds has not been comprehensively studied to date. The objective of this study was to investigate acute effects of clinically relevant antiarrhythmic drugs on human K2P17.1 channels to provide a more complete picture of K2P17.1 electropharmacology. Whole-cell patch clamp and two-electrode voltage clamp electrophysiology was employed to study human K2P17.1 channel pharmacology. K2P17.1 channels expressed in Xenopus laevis oocytes were screened for sensitivity to antiarrhythmic drugs, revealing significant activation by propafenone (+ 296%; 100 μM), quinidine (+ 58%; 100 μM), mexiletine (+ 21%; 100 μM), propranolol (+ 139%; 100 μM), and metoprolol (+ 17%; 100 μM) within 60 min. In addition, the currents were inhibited by amiodarone (- 13%; 100 μM), sotalol (- 10%; 100 μM), verapamil (- 21%; 100 μM), and ranolazine (- 8%; 100 μM). K2P17.1 channels were not significantly affected by ajmaline and carvedilol. Concentration-dependent K2P17.1 activation by propafenone was characterized in more detail. The onset of activation was fast, and current-voltage relationships were not modulated by propafenone. K2P17.1 activation was confirmed in mammalian Chinese hamster ovary cells, revealing 7.8-fold current increase by 100 μM propafenone. Human K2P17.1 channels were sensitive to multiple antiarrhythmic drugs. Differential pharmacological regulation of repolarizing K2P17.1 background K+ channels may be employed for personalized antiarrhythmic therapy.
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33
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Staudacher I, Illg C, Gierten J, Seehausen S, Schweizer PA, Katus HA, Thomas D. Identification and functional characterization of zebrafish K 2P 17.1 (TASK-4, TALK-2) two-pore-domain K + channels. Eur J Pharmacol 2018; 831:94-102. [DOI: 10.1016/j.ejphar.2018.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/04/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022]
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Loucif AJC, Saintot P, Liu J, Antonio BM, Zellmer SG, Yoger K, Veale EL, Wilbrey A, Omoto K, Cao L, Gutteridge A, Castle NA, Stevens EB, Mathie A. GI-530159, a novel, selective, mechanosensitive two-pore-domain potassium (K 2P ) channel opener, reduces rat dorsal root ganglion neuron excitability. Br J Pharmacol 2018; 175:2272-2283. [PMID: 29150838 PMCID: PMC5980259 DOI: 10.1111/bph.14098] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE TREK two-pore-domain potassium (K2P ) channels play a critical role in regulating the excitability of somatosensory nociceptive neurons and are important mediators of pain perception. An understanding of the roles of TREK channels in pain perception and, indeed, in other pathophysiological conditions, has been severely hampered by the lack of potent and/or selective activators and inhibitors. In this study, we describe a new, selective opener of TREK channels, GI-530159. EXPERIMENTAL APPROACH The effect of GI-530159 on TREK channels was demonstrated using 86 Rb efflux assays, whole-cell and single-channel patch-clamp recordings from recombinant TREK channels. The expression of K2P 2.1 (TREK1), K2P 10.1 (TREK2) and K2P 4.1 (TRAAK) channels was determined using transcriptome analysis from single dorsal root ganglion (DRG) cells. Current-clamp recordings from cultured rat DRG neurons were used to measure the effect of GI-530159 on neuronal excitability. KEY RESULTS For recombinant human TREK1 channels, GI-530159 had similar low EC50 values in Rb efflux experiments and electrophysiological recordings. It activated TREK2 channels, but it had no detectable action on TRAAK channels nor any significant effect on other K channels tested. Current-clamp recordings from cultured rat DRG neurones showed that application of GI-530159 at 1 μM resulted in a significant reduction in firing frequency and a small hyperpolarization of resting membrane potential. CONCLUSIONS AND IMPLICATIONS This study provides pharmacological evidence for the presence of mechanosensitive TREK K2P channels in sensory neurones and suggests that development of selective K2P channel openers like GI-530159 could aid in the development of novel analgesic agents. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
| | | | | | | | | | | | - Emma L Veale
- Medway School of PharmacyUniversity of KentChatham MaritimeKentUK
| | | | | | | | | | | | | | - Alistair Mathie
- Medway School of PharmacyUniversity of KentChatham MaritimeKentUK
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35
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Kwon H, Jang D, Choi M, Lee J, Jeong K, Pak Y. Alternative translation initiation of Caveolin-2 desensitizes insulin signaling through dephosphorylation of insulin receptor by PTP1B and causes insulin resistance. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2169-2182. [PMID: 29604334 DOI: 10.1016/j.bbadis.2018.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/08/2018] [Accepted: 03/26/2018] [Indexed: 12/30/2022]
Abstract
Insulin resistance, defined as attenuated sensitivity responding to insulin, impairs insulin action. Direct causes and molecular mechanisms of insulin resistance have thus far remained elusive. Here we show that alternative translation initiation (ATI) of Caveolin-2 (Cav-2) regulates insulin sensitivity. Cav-2β isoform yielded by ATI desensitizes insulin receptor (IR) via dephosphorylation by protein-tyrosine phosphatase 1B (PTP1B), and subsequent endocytosis and lysosomal degradation of IR, causing insulin resistance. Blockage of Cav-2 ATI protects against insulin resistance by preventing Cav-2β-PTP1B-directed IR desensitization, thereby normalizing insulin sensitivity and glucose uptake. Our findings show that Cav-2β is a negative regulator of IR signaling, and identify a mechanism causing insulin resistance through control of insulin sensitivity via Cav-2 ATI.
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Affiliation(s)
- Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Donghwan Jang
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Jaewoong Lee
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Kyuho Jeong
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea.
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36
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Riegelhaupt PM, Tibbs GR, Goldstein PA. HCN and K 2P Channels in Anesthetic Mechanisms Research. Methods Enzymol 2018; 602:391-416. [PMID: 29588040 DOI: 10.1016/bs.mie.2018.01.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ability of a diverse group of agents to produce general anesthesia has long been an area of intense speculation and investigation. Over the past century, we have seen a paradigm shift from proposing that the anesthetized state arises from nonspecific interaction of anesthetics with the lipid membrane to the recognition that the function of distinct, and identifiable, membrane-embedded proteins is dramatically altered in the presence of intravenous and inhaled agents. Among proteinaceous targets, metabotropic and ionotropic receptors garnered much of the attention over the last 30 years, and it is only relatively recently that voltage-gated ion channels have clearly and rigorously been shown to be important molecular targets. In this review, we will consider the experimental issues relevant to two important ion channel anesthetic targets, HCN and K2P.
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Affiliation(s)
| | - Gareth R Tibbs
- Weill Cornell Medical College, New York, NY, United States
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37
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Täger J, Kohl S, Birch DG, Wheaton DKH, Wissinger B, Reuter P. An early nonsense mutation facilitates the expression of a short isoform of CNGA3 by alternative translation initiation. Exp Eye Res 2018; 171:48-53. [PMID: 29499183 DOI: 10.1016/j.exer.2018.02.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 02/26/2018] [Accepted: 02/26/2018] [Indexed: 11/24/2022]
Abstract
The cyclic nucleotide-gated (CNG) channel - composed of CNGA3 and CNGB3 subunits - mediates the influx of cations in cone photoreceptors after light stimulation and thus is a key element in cone phototransduction. Mutations in CNGA3 and CNGB3 are associated with achromatopsia, a rare autosomal recessive retinal disorder. Here, we demonstrate that the presence of an early nonsense mutation in CNGA3 induces the usage of a downstream alternative translation initiation site giving rise to a short CNGA3 isoform. The expression of this short isoform was verified by Western blot analysis and DAB staining of HEK293 cells and cone photoreceptor-like 661W cells expressing CNGA3-GST fusion constructs. Functionality of the short isoform was confirmed by a cellular calcium influx assay. Furthermore, patients carrying an early nonsense mutation were analyzed for residual cone photoreceptor function in order to identify a potential role of the short isoform to modify the clinical outcome in achromatopsia patients. Yet the results suggest that the short isoform is not able to compensate for the loss of the long isoform leaving the biological role of this variant unclear.
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Affiliation(s)
- Joachim Täger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany; Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | | | | | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
| | - Peggy Reuter
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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38
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Goldstein SA. Sodium leak through K2P potassium channels and cardiac arrhythmia, an emerging theme. EMBO Mol Med 2018; 9:399-402. [PMID: 28258154 PMCID: PMC5376743 DOI: 10.15252/emmm.201607479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In this issue of EMBO Molecular Medicine, Decher et al (2017) identify a point mutation in the K2P2 (TREK‐1) potassium (K+) channel that changes function in just those ways expected to predispose to right ventricular outflow tract (RVOT) ventricular tachycardia (VT) in the patient they study. Whereas wild‐type channels are selective for K+ and inhibited by β‐adrenergic stimulation, mutant I267T channels pass sodium (Na+) into the cells, even during β‐adrenergic stimulation, and are more active in response to membrane stretch, changes predicted to enhance cardiac myocyte excitability. The report contributes to accumulating evidence for Na+ leak via K2P channels in association with normal development (Thomas et al, 2008), acquired arrhythmia (Ma et al, 2011), and now a missense mutation. Decher et al (2017) both inform and direct us toward interesting opportunities for further investigation.
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39
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Kim EJ, Lee DK, Hong SG, Han J, Kang D. Activation of TREK-1, but Not TREK-2, Channel by Mood Stabilizers. Int J Mol Sci 2017; 18:ijms18112460. [PMID: 29156592 PMCID: PMC5713426 DOI: 10.3390/ijms18112460] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 01/22/2023] Open
Abstract
Earlier studies have demonstrated that the tandem pore domain weak inward rectifying K+ channel (TWIK)-related K+ (TREK)-1 channel is inhibited by antidepressants and is associated with major depression. However, little is known about the effect of mood stabilizers that are commonly used for treatment of bipolar disorder on TREK channels, members of the two-pore domain K+ (K2P) channel family. This study sought to investigate the effect of mood stabilizers on TREK-1 and TREK-2 channels. HEK-293A cells were transfected with human TREK-1 or TREK-2 DNA. The effect of mood stabilizers on TREK-1 and TREK-2 was studied using the patch clamp technique. Changes in TREK protein expression by mood stabilizers were studied in the HT-22 mouse hippocampal neuronal cells using western blot analysis. Lithium chloride (LiCl, 1 mM), gabapentin (100 μM), valproate (100 μM), and carbamazepine (100 μM) increased TREK-1 currents by 31 ± 14%, 25 ± 11%, 28 ± 12%, and 72 ± 12%, respectively, whereas they had no effect on TREK-2 channel activity. In addition, western blot analysis showed LiCl and carbamazepine slightly upregulated TREK-1 expression, but not TREK-2 in the HT-22 cells. These results suggest that TREK-1 could be a potential therapeutic target for treatment of bipolar disorders as well as depression, while TREK-2 is a target well suited for treatment of major depression.
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Affiliation(s)
- Eun-Jin Kim
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Dong Kun Lee
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Seong-Geun Hong
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Jaehee Han
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Dawon Kang
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
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40
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Decher N, Ortiz-Bonnin B, Friedrich C, Schewe M, Kiper AK, Rinné S, Seemann G, Peyronnet R, Zumhagen S, Bustos D, Kockskämper J, Kohl P, Just S, González W, Baukrowitz T, Stallmeyer B, Schulze-Bahr E. Sodium permeable and "hypersensitive" TREK-1 channels cause ventricular tachycardia. EMBO Mol Med 2017; 9:403-414. [PMID: 28242754 PMCID: PMC5376757 DOI: 10.15252/emmm.201606690] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In a patient with right ventricular outflow tract (RVOT) tachycardia, we identified a heterozygous point mutation in the selectivity filter of the stretch-activated K2P potassium channel TREK-1 (KCNK2 or K2P2.1). This mutation introduces abnormal sodium permeability to TREK-1. In addition, mutant channels exhibit a hypersensitivity to stretch-activation, suggesting that the selectivity filter is directly involved in stretch-induced activation and desensitization. Increased sodium permeability and stretch-sensitivity of mutant TREK-1 channels may trigger arrhythmias in areas of the heart with high physical strain such as the RVOT We present a pharmacological strategy to rescue the selectivity defect of the TREK-1 pore. Our findings provide important insights for future studies of K2P channel stretch-activation and the role of TREK-1 in mechano-electrical feedback in the heart.
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Affiliation(s)
- Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Beatriz Ortiz-Bonnin
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Corinna Friedrich
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Marcus Schewe
- Institute of Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Aytug K Kiper
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Gunnar Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sven Zumhagen
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Daniel Bustos
- Center for Bioinformatics and Molecular Simulation, University of Talca, Talca, Chile
| | - Jens Kockskämper
- Institute of Pharmacology and Clinical Pharmacy, Biochemical and Pharmacological Center (BPC) Philipps-University of Marburg, Marburg, Germany
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Steffen Just
- Molecular Cardiology, University Hospital Ulm, Ulm, Germany
| | - Wendy González
- Center for Bioinformatics and Molecular Simulation, University of Talca, Talca, Chile
| | - Thomas Baukrowitz
- Institute of Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Birgit Stallmeyer
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Eric Schulze-Bahr
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
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Nematian-Ardestani E, Jarerattanachat V, Aryal P, Sansom MSP, Tucker SJ. The effects of stretch activation on ionic selectivity of the TREK-2 K2P K + channel. Channels (Austin) 2017; 11:482-486. [PMID: 28723241 PMCID: PMC5626358 DOI: 10.1080/19336950.2017.1356955] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The TREK-2 (KCNK10) K2P potassium channel can be regulated by variety of polymodal stimuli including pressure. In a recent study, we demonstrated that this mechanosensitive K+ channel responds to changes in membrane tension by undergoing a major structural change from its ‘down’ state to the more expanded ‘up’ state conformation. These changes are mostly restricted to the lower part of the protein within the bilayer, but are allosterically coupled to the primary gating mechanism located within the selectivity filter. However, any such structural changes within the filter also have the potential to alter ionic selectivity and there are reports that some K2Ps, including TREK channels, exhibit a dynamic ionic selectivity. In this addendum to our previous study we have therefore examined whether the selectivity of TREK-2 is altered by stretch activation. Our results reveal that the filter remains stable and highly selective for K+ over Na+ during stretch activation, and that permeability to a range of other cations (Rb+, Cs+ and NH4+) also does not change. The asymmetric structural changes that occur during stretch activation therefore allow the channel to respond to changes in membrane tension without a loss of K+ selectivity.
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Affiliation(s)
- Ehsan Nematian-Ardestani
- a Clarendon Laboratory, Department of Physics and OXION Initiative in Ion Channels and Disease , University of Oxford , Oxford , UK
| | - Viwan Jarerattanachat
- a Clarendon Laboratory, Department of Physics and OXION Initiative in Ion Channels and Disease , University of Oxford , Oxford , UK
| | - Prafulla Aryal
- a Clarendon Laboratory, Department of Physics and OXION Initiative in Ion Channels and Disease , University of Oxford , Oxford , UK
| | - Mark S P Sansom
- a Clarendon Laboratory, Department of Physics and OXION Initiative in Ion Channels and Disease , University of Oxford , Oxford , UK
| | - Stephen J Tucker
- a Clarendon Laboratory, Department of Physics and OXION Initiative in Ion Channels and Disease , University of Oxford , Oxford , UK
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Leithe E, Mesnil M, Aasen T. The connexin 43 C-terminus: A tail of many tales. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:48-64. [PMID: 28526583 DOI: 10.1016/j.bbamem.2017.05.008] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
Abstract
Connexins are chordate gap junction channel proteins that, by enabling direct communication between the cytosols of adjacent cells, create a unique cell signalling network. Gap junctional intercellular communication (GJIC) has important roles in controlling cell growth and differentiation and in tissue development and homeostasis. Moreover, several non-canonical connexin functions unrelated to GJIC have been discovered. Of the 21 members of the human connexin family, connexin 43 (Cx43) is the most widely expressed and studied. The long cytosolic C-terminus (CT) of Cx43 is subject to extensive post-translational modifications that modulate its intracellular trafficking and gap junction channel gating. Moreover, the Cx43 CT contains multiple domains involved in protein interactions that permit crosstalk between Cx43 and cytoskeletal and regulatory proteins. These domains endow Cx43 with the capacity to affect cell growth and differentiation independently of GJIC. Here, we review the current understanding of the regulation and unique functions of the Cx43 CT, both as an essential component of full-length Cx43 and as an independent signalling hub. We highlight the complex regulatory and signalling networks controlled by the Cx43 CT, including the extensive protein interactome that underlies both gap junction channel-dependent and -independent functions. We discuss these data in relation to the recent discovery of the direct translation of specific truncated forms of Cx43. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, University of Oslo, NO-0424 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, France
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
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43
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Schmidt C, Wiedmann F, Kallenberger SM, Ratte A, Schulte JS, Scholz B, Müller FU, Voigt N, Zafeiriou MP, Ehrlich JR, Tochtermann U, Veres G, Ruhparwar A, Karck M, Katus HA, Thomas D. Stretch-activated two-pore-domain (K 2P) potassium channels in the heart: Focus on atrial fibrillation and heart failure. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:233-243. [PMID: 28526353 DOI: 10.1016/j.pbiomolbio.2017.05.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 12/18/2022]
Abstract
Two-pore-domain potassium (K2P) channels modulate cellular excitability. The significance of stretch-activated cardiac K2P channels (K2P2.1, TREK-1, KCNK2; K2P4.1, TRAAK, KCNK4; K2P10.1, TREK-2, KCNK10) in heart disease has not been elucidated in detail. The aim of this work was to assess expression and remodeling of mechanosensitive K2P channels in atrial fibrillation (AF) and heart failure (HF) patients in comparison to murine models. Cardiac K2P channel levels were quantified in atrial (A) and ventricular (V) tissue obtained from patients undergoing open heart surgery. In addition, control mice and mouse models of AF (cAMP-response element modulator (CREM)-IbΔC-X transgenic animals) or HF (cardiac dysfunction induced by transverse aortic constriction, TAC) were employed. Human and murine KCNK2 displayed highest mRNA abundance among mechanosensitive members of the K2P channel family (V > A). Disease-associated K2P2.1 remodeling was studied in detail. In patients with impaired left ventricular function, atrial KCNK2 (K2P2.1) mRNA and protein expression was significantly reduced. In AF subjects, downregulation of atrial and ventricular KCNK2 (K2P2.1) mRNA and protein levels was observed. AF-associated suppression of atrial Kcnk2 (K2P2.1) mRNA and protein was recapitulated in CREM-transgenic mice. Ventricular Kcnk2 expression was not significantly altered in mouse models of disease. In conclusion, mechanosensitive K2P2.1 and K2P10.1 K+ channels are expressed throughout the heart. HF- and AF-associated downregulation of KCNK2 (K2P2.1) mRNA and protein levels suggest a mechanistic contribution to cardiac arrhythmogenesis.
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Affiliation(s)
- Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Felix Wiedmann
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Stefan M Kallenberger
- Department for Bioinformatics and Functional Genomics, Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Antonius Ratte
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Jan S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Beatrix Scholz
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Maria-Patapia Zafeiriou
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Joachim R Ehrlich
- Department of Cardiology, Internal Medicine III, Goethe University, Frankfurt, Germany; Department of Cardiology, St. Josefs-Hospital, Wiesbaden, Germany
| | - Ursula Tochtermann
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Gábor Veres
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Arjang Ruhparwar
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Matthias Karck
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany.
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Decher N, Kiper AK, Rinné S. Stretch-activated potassium currents in the heart: Focus on TREK-1 and arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:223-232. [PMID: 28526352 DOI: 10.1016/j.pbiomolbio.2017.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 12/26/2022]
Abstract
This review focuses on the role and the molecular candidates of the cardiac stretch-activated potassium current (SAK). The functional properties of the two-pore domain potassium (K2P) channel TREK-1, a major candidate for the cardiac SAK, are analyzed and the molecular mechanism of stretch-activation in K2P potassium channels is discussed. Furthermore, the functional modulation of TREK-1 by different cardiac interaction partners, as well as evidence for the functional role of the stretch-dependent TREK-1 and its putative subunits in the heart is reviewed. In addition, we summarize the recent evidence that TREK-1 is involved in the pathogenesis of human cardiac arrhythmias.
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Affiliation(s)
- Niels Decher
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany.
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
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45
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Hughes S, Foster RG, Peirson SN, Hankins MW. Expression and localisation of two-pore domain (K2P) background leak potassium ion channels in the mouse retina. Sci Rep 2017; 7:46085. [PMID: 28443635 PMCID: PMC5405414 DOI: 10.1038/srep46085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
Two-pore domain (K2P) potassium channels perform essential roles in neuronal function. These channels produce background leak type potassium currents that act to regulate resting membrane potential and levels of cellular excitability. 15 different K2P channels have been identified in mammals and these channels perform important roles in a wide number of physiological systems. However, to date there is only limited data available concerning the expression and role of K2P channels in the retina. In this study we conduct the first comprehensive study of K2P channel expression in the retina. Our data show that K2P channels are widely expressed in the mouse retina, with variations in expression detected at different times of day and throughout postnatal development. The highest levels of K2P channel expression are observed for Müller cells (TWIK-1, TASK-3, TRAAK, and TREK-2) and retinal ganglion cells (TASK-1, TREK-1, TWIK-1, TWIK-2 and TWIK-3). These data offer new insight into the channels that regulate the resting membrane potential and electrical activity of retinal cells, and suggests that K2P channels are well placed to act as central regulators of visual signalling pathways. The prominent role of K2P channels in neuroprotection offers novel avenues of research into the treatment of common retinal diseases.
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Affiliation(s)
- Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Russell G. Foster
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N. Peirson
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Mark W. Hankins
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
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46
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TREK-1 (K2P2.1) K+ channels are suppressed in patients with atrial fibrillation and heart failure and provide therapeutic targets for rhythm control. Basic Res Cardiol 2016; 112:8. [DOI: 10.1007/s00395-016-0597-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/12/2016] [Indexed: 12/16/2022]
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47
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Therapeutic targeting of two-pore-domain potassium (K(2P)) channels in the cardiovascular system. Clin Sci (Lond) 2016; 130:643-50. [PMID: 26993052 DOI: 10.1042/cs20150533] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The improvement of treatment strategies in cardiovascular medicine is an ongoing process that requires constant optimization. The ability of a therapeutic intervention to prevent cardiovascular pathology largely depends on its capacity to suppress the underlying mechanisms. Attenuation or reversal of disease-specific pathways has emerged as a promising paradigm, providing a mechanistic rationale for patient-tailored therapy. Two-pore-domain K(+) (K(2P)) channels conduct outward K(+) currents that stabilize the resting membrane potential and facilitate action potential repolarization. K(2P) expression in the cardiovascular system and polymodal K2P current regulation suggest functional significance and potential therapeutic roles of the channels. Recent work has focused primarily on K(2P)1.1 [tandem of pore domains in a weak inwardly rectifying K(+) channel (TWIK)-1], K(2P)2.1 [TWIK-related K(+) channel (TREK)-1], and K(2P)3.1 [TWIK-related acid-sensitive K(+) channel (TASK)-1] channels and their role in heart and vessels. K(2P) currents have been implicated in atrial and ventricular arrhythmogenesis and in setting the vascular tone. Furthermore, the association of genetic alterations in K(2P)3.1 channels with atrial fibrillation, cardiac conduction disorders and pulmonary arterial hypertension demonstrates the relevance of the channels in cardiovascular disease. The function, regulation and clinical significance of cardiovascular K(2P) channels are summarized in the present review, and therapeutic options are emphasized.
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48
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Lengyel M, Czirják G, Enyedi P. Formation of Functional Heterodimers by TREK-1 and TREK-2 Two-pore Domain Potassium Channel Subunits. J Biol Chem 2016; 291:13649-61. [PMID: 27129242 DOI: 10.1074/jbc.m116.719039] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Indexed: 11/06/2022] Open
Abstract
Two-pore domain (K2P) potassium channels are the major molecular correlates of the background (leak) K(+) current in a wide variety of cell types. They generally play a key role in setting the resting membrane potential and regulate the response of excitable cells to various stimuli. K2P channels usually function as homodimers, and only a few examples of heteromerization have been previously reported. Expression of the TREK (TWIK-related K(+) channel) subfamily members of K2P channels often overlaps in neurons and in other excitable cells. Here, we demonstrate that heterologous coexpression of TREK-1 and TREK-2 subunits results in the formation of functional heterodimers. Taking advantage of a tandem construct (in which the two different subunits were linked together to enforce heterodimerization), we characterized the biophysical and pharmacological properties of the TREK-1/TREK-2 current. The heteromer was inhibited by extracellular acidification and by spadin similarly to TREK-1, and its ruthenium red sensitivity was intermediate between TREK-1 and TREK-2 homodimers. The heterodimer has also been distinguished from the homodimers by its unique single channel conductance. Assembly of the two different subunits was confirmed by coimmunoprecipitation of epitope-tagged TREK-1 and TREK-2 subunits, coexpressed in Xenopus oocytes. Formation of TREK-1/TREK-2 channels was also demonstrated in native dorsal root ganglion neurons indicating that heterodimerization may provide greater diversity of leak K(+) conductances also in native tissues.
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Affiliation(s)
- Miklós Lengyel
- From the Department of Physiology, Semmelweis University, H-1428 Budapest, Hungary
| | - Gábor Czirják
- From the Department of Physiology, Semmelweis University, H-1428 Budapest, Hungary
| | - Péter Enyedi
- From the Department of Physiology, Semmelweis University, H-1428 Budapest, Hungary
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49
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Veale EL, Mathie A. Aristolochic acid, a plant extract used in the treatment of pain and linked to Balkan endemic nephropathy, is a regulator of K2P channels. Br J Pharmacol 2016; 173:1639-52. [PMID: 26914156 PMCID: PMC4842925 DOI: 10.1111/bph.13465] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 01/08/2023] Open
Abstract
Background and Purpose Aristolochic acid (AristA) is found in plants used in traditional medicines to treat pain. We investigated the action of AristA on TREK and TRESK, potassium (K2P) channels, which are potential therapeutic targets in pain. Balkan endemic nephropathy (BEN) is a renal disease associated with AristA consumption. A mutation of TASK‐2 (K2P5.1) channels (T108P) is seen in some patients susceptible to BEN, so we investigated how both this mutation and AristA affected TASK‐2 channels. Experimental Approach Currents through wild‐type and mutated human K2P channels expressed in tsA201 cells were measured using whole‐cell patch‐clamp recordings in the presence and absence of AristA. Key Results TREK‐1‐ and TREK‐2‐mediated currents were enhanced by AristA (100 μM), whereas TRESK was inhibited. Inhibition of TRESK did not depend on the phosphorylation of key intracellular serines but was completely blocked by mutation of bulky residues in the inner pore (F145A_F352A). The TASK‐2_T108P mutation markedly reduced both current density and ion selectivity. A related mutation (T108C) had similar but less marked effects. External alkalization and application of flufenamic acid enhanced TASK‐2 and TASK‐2_T108C current but did not affect TASK‐2_T108P current. AristA (300 μM) produced a modest enhancement of TASK‐2 current. Conclusions and Implications Enhancement of TREK‐1 and TREK‐2 and inhibition of TRESK by AristA may contribute to therapeutically useful effects of this compound in pain. Whilst AristA is unlikely to interact directly with TASK‐2 channels in BEN, loss of functional TASK‐2 channels may indirectly increase susceptibility to AristA toxicity.
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Affiliation(s)
- Emma L Veale
- Medway School of Pharmacy, University of Kent, Kent, UK
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50
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Mixing and matching TREK/TRAAK subunits generate heterodimeric K2P channels with unique properties. Proc Natl Acad Sci U S A 2016; 113:4200-5. [PMID: 27035965 DOI: 10.1073/pnas.1522748113] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The tandem of pore domain in a weak inwardly rectifying K(+) channel (Twik)-related acid-arachidonic activated K(+) channel (TRAAK) and Twik-related K(+) channels (TREK) 1 and TREK2 are active as homodimers gated by stretch, fatty acids, pH, and G protein-coupled receptors. These two-pore domain potassium (K2P) channels are broadly expressed in the nervous system where they control excitability. TREK/TRAAK KO mice display altered phenotypes related to nociception, neuroprotection afforded by polyunsaturated fatty acids, learning and memory, mood control, and sensitivity to general anesthetics. These channels have emerged as promising targets for the development of new classes of anesthetics, analgesics, antidepressants, neuroprotective agents, and drugs against addiction. Here, we show that the TREK1, TREK2, and TRAAK subunits assemble and form active heterodimeric channels with electrophysiological, regulatory, and pharmacological properties different from those of homodimeric channels. Heteromerization occurs between all TREK variants produced by alternative splicing and alternative translation initiation. These results unveil a previously unexpected diversity of K2P channels that will be challenging to analyze in vivo, but which opens new perspectives for the development of clinically relevant drugs.
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