51
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Cao E. Structural mechanisms of transient receptor potential ion channels. J Gen Physiol 2021; 152:133640. [PMID: 31972006 PMCID: PMC7054860 DOI: 10.1085/jgp.201811998] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 01/03/2020] [Indexed: 12/26/2022] Open
Abstract
Transient receptor potential (TRP) ion channels are evolutionarily ancient sensory proteins that detect and integrate a wide range of physical and chemical stimuli. TRP channels are fundamental for numerous biological processes and are therefore associated with a multitude of inherited and acquired human disorders. In contrast to many other major ion channel families, high-resolution structures of TRP channels were not available before 2013. Remarkably, however, the subsequent “resolution revolution” in cryo-EM has led to an explosion of TRP structures in the last few years. These structures have confirmed that TRP channels assemble as tetramers and resemble voltage-gated ion channels in their overall architecture. But beyond the relatively conserved transmembrane core embedded within the lipid bilayer, each TRP subtype appears to be endowed with a unique set of soluble domains that may confer diverse regulatory mechanisms. Importantly, TRP channel structures have revealed sites and mechanisms of action of numerous synthetic and natural compounds, as well as those for endogenous ligands such as lipids, Ca2+, and calmodulin. Here, I discuss these recent findings with a particular focus on the conserved transmembrane region and how these structures may help to rationally target this important class of ion channels for the treatment of numerous human conditions.
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Affiliation(s)
- Erhu Cao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
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52
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Canales Coutiño B, Mayor R. Mechanosensitive ion channels in cell migration. Cells Dev 2021; 166:203683. [PMID: 33994356 PMCID: PMC8240554 DOI: 10.1016/j.cdev.2021.203683] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 01/05/2023]
Abstract
Cellular processes are initiated and regulated by different stimuli, including mechanical forces. Cell membrane mechanosensors represent the first step towards the conversion of mechanical stimuli to a biochemical or electrical response. Mechanosensitive (MS) ion channels form a growing family of ion gating channels that respond to direct physical force or plasma membrane deformations. A number of calcium (Ca2+) permeable MS channels are known to regulate the initiation, direction, and persistence of cell migration during development and tumour progression. While the evidence that links individual MS ion channels to cell migration is growing, a unified analysis of the molecular mechanisms regulated downstream of MS ion channel activation is lacking. In this review, we describe the MS ion channel families known to regulate cell migration. We discuss the molecular mechanisms that act downstream of MS ion channels with an emphasis on Ca2+ mediated processes. Finally, we propose the future directions and impact of MS ion channel activity in the field of cell migration.
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Affiliation(s)
- Brenda Canales Coutiño
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
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53
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Conde J, Pumroy RA, Baker C, Rodrigues T, Guerreiro A, Sousa BB, Marques MC, de Almeida BP, Lee S, Leites EP, Picard D, Samanta A, Vaz SH, Sieglitz F, Langini M, Remke M, Roque R, Weiss T, Weller M, Liu Y, Han S, Corzana F, Morais VA, Faria C, Carvalho T, Filippakopoulos P, Snijder B, Barbosa-Morais NL, Moiseenkova-Bell VY, Bernardes GJL. Allosteric Antagonist Modulation of TRPV2 by Piperlongumine Impairs Glioblastoma Progression. ACS CENTRAL SCIENCE 2021; 7:868-881. [PMID: 34079902 PMCID: PMC8161495 DOI: 10.1021/acscentsci.1c00070] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 05/04/2023]
Abstract
The use of computational tools to identify biological targets of natural products with anticancer properties and unknown modes of action is gaining momentum. We employed self-organizing maps to deconvolute the phenotypic effects of piperlongumine (PL) and establish a link to modulation of the human transient receptor potential vanilloid 2 (hTRPV2) channel. The structure of the PL-bound full-length rat TRPV2 channel was determined by cryo-EM. PL binds to a transient allosteric pocket responsible for a new mode of anticancer activity against glioblastoma (GBM) in which hTRPV2 is overexpressed. Calcium imaging experiments revealed the importance of Arg539 and Thr522 residues on the antagonistic effect of PL and calcium influx modulation of the TRPV2 channel. Downregulation of hTRPV2 reduces sensitivity to PL and decreases ROS production. Analysis of GBM patient samples associates hTRPV2 overexpression with tumor grade, disease progression, and poor prognosis. Extensive tumor abrogation and long term survival was achieved in two murine models of orthotopic GBM by formulating PL in an implantable scaffold/hydrogel for sustained local therapy. Furthermore, in primary tumor samples derived from GBM patients, we observed a selective reduction of malignant cells in response to PL ex vivo. Our results establish a broadly applicable strategy, leveraging data-motivated research hypotheses for the discovery of novel means tackling cancer.
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Affiliation(s)
- João Conde
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Ruth A. Pumroy
- Department
of Systems Pharmacology and Translational Therapeutics, Perelman School
of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Charlotte Baker
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Tiago Rodrigues
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Ana Guerreiro
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Bárbara B. Sousa
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Marta C. Marques
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Bernardo P. de Almeida
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Sohyon Lee
- Institute
of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Elvira P. Leites
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Daniel Picard
- Department
of Pediatric Neuro-Oncogenomics, DKFZ, Heidelberg 69120, Germany
- Department of Pediatric Neuro-Oncogenomics, DKTK, Essen D-45147, Germany
- Department
of Pediatric Oncology, Hematology, and Clinical Immunology, Medical
Faculty, University Hospital Düsseldorf, Düsseldorf 40225, Germany
| | - Amrita Samanta
- Department
of Systems Pharmacology and Translational Therapeutics, Perelman School
of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Sandra H. Vaz
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Florian Sieglitz
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Maike Langini
- Department
of Pediatric Neuro-Oncogenomics, DKFZ, Heidelberg 69120, Germany
- Department of Pediatric Neuro-Oncogenomics, DKTK, Essen D-45147, Germany
- Department
of Pediatric Oncology, Hematology, and Clinical Immunology, Medical
Faculty, University Hospital Düsseldorf, Düsseldorf 40225, Germany
| | - Marc Remke
- Department
of Pediatric Neuro-Oncogenomics, DKFZ, Heidelberg 69120, Germany
- Department of Pediatric Neuro-Oncogenomics, DKTK, Essen D-45147, Germany
- Department
of Pediatric Oncology, Hematology, and Clinical Immunology, Medical
Faculty, University Hospital Düsseldorf, Düsseldorf 40225, Germany
| | - Rafael Roque
- Laboratório
de Neuropatologia, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte (CHLN) EPE, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Tobias Weiss
- Department
of Neurology and Brain Tumour Center, University
Hospital Zürich and University of Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - Michael Weller
- Department
of Neurology and Brain Tumour Center, University
Hospital Zürich and University of Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - Yuhang Liu
- Discovery
Sciences, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, Connecticut 06340, United States
| | - Seungil Han
- Discovery
Sciences, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, Connecticut 06340, United States
| | - Francisco Corzana
- Departamento
de Química, Universidad de La Rioja, 26006 Logroño, Spain
| | - Vanessa A. Morais
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Cláudia
C. Faria
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
- Department
of Neurosurgery, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte (CHULN) EPE, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Tânia Carvalho
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Panagis Filippakopoulos
- Structural
Genomics Consortium, Oxford University, Old Road Campus Research Building,
Roosevelt Drive, OX3 7DQ Oxford, United Kingdom
| | - Berend Snijder
- Institute
of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Nuno L. Barbosa-Morais
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Vera Y. Moiseenkova-Bell
- Department
of Systems Pharmacology and Translational Therapeutics, Perelman School
of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- E-mail:
| | - Gonçalo J. L. Bernardes
- Instituto
de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, CB2 1EW Cambridge, United Kingdom
- E-mail: ;
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54
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Pang JJ, Gao F, Wu SM. Generators of Pressure-Evoked Currents in Vertebrate Outer Retinal Neurons. Cells 2021; 10:cells10061288. [PMID: 34067375 PMCID: PMC8224636 DOI: 10.3390/cells10061288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
(1) Background: High-tension glaucoma damages the peripheral vision dominated by rods. How mechanosensitive channels (MSCs) in the outer retina mediate pressure responses is unclear. (2) Methods: Immunocytochemistry, patch clamp, and channel fluorescence were used to study MSCs in salamander photoreceptors. (3) Results: Immunoreactivity of transient receptor potential channel vanilloid 4 (TRPV4) was revealed in the outer plexiform layer, K+ channel TRAAK in the photoreceptor outer segment (OS), and TRPV2 in some rod OS disks. Pressure on the rod inner segment evoked sustained currents of three components: (A) the inward current at <-50 mV (Ipi), sensitive to Co2+; (B) leak outward current at ≥-80 mV (Ipo), sensitive to intracellular Cs+ and ruthenium red; and (C) cation current reversed at ~10 mV (Ipc). Hypotonicity induced slow currents like Ipc. Environmental pressure and light increased the FM 1-43-identified open MSCs in the OS membrane, while pressure on the OS with internal Cs+ closed a Ca2+-dependent current reversed at ~0 mV. Rod photocurrents were thermosensitive and affected by MSC blockers. (4) Conclusions: Rods possess depolarizing (TRPV) and hyperpolarizing (K+) MSCs, which mediate mutually compensating currents between -50 mV and 10 mV, serve as an electrical cushion to minimize the impact of ocular mechanical stress.
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55
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Nadezhdin KD, Neuberger A, Nikolaev YA, Murphy LA, Gracheva EO, Bagriantsev SN, Sobolevsky AI. Extracellular cap domain is an essential component of the TRPV1 gating mechanism. Nat Commun 2021; 12:2154. [PMID: 33846324 PMCID: PMC8041747 DOI: 10.1038/s41467-021-22507-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/18/2021] [Indexed: 02/01/2023] Open
Abstract
Transient receptor potential (TRP) channels are polymodal molecular sensors involved in numerous physiological processes and implicated in a variety of human diseases. Several structures of the founding member of the TRP channel family, TRPV1, are available, all of which were determined for the protein missing the N- and C-termini and the extracellular S5-P-loop. Here, we present structures of the full-length thirteen-lined ground squirrel TRPV1 solved by cryo-EM. Our structures resolve the extracellular cap domain formed by the S5-P-loops and the C-terminus that wraps around the three-stranded β-sheet connecting elements of the TRPV1 intracellular skirt. The cap domain forms a dome above the pore's extracellular entrance, with four portals leading to the ion conductance pathway. Deletion of the cap increases the TRPV1 average conductance, reduces the open probability and affects ion selectivity. Our data show that both the termini and the cap domain are critical determinants of TRPV1 function.
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Affiliation(s)
- Kirill D Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Yury A Nikolaev
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Lyle A Murphy
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Elena O Gracheva
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA
| | - Sviatoslav N Bagriantsev
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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56
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Amphipathic environments for determining the structure of membrane proteins by single-particle electron cryo-microscopy. Q Rev Biophys 2021; 54:e6. [PMID: 33785082 DOI: 10.1017/s0033583521000044] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Over the past decade, the structural biology of membrane proteins (MPs) has taken a new turn thanks to epoch-making technical progress in single-particle electron cryo-microscopy (cryo-EM) as well as to improvements in sample preparation. The present analysis provides an overview of the extent and modes of usage of the various types of surfactants for cryo-EM studies. Digitonin, dodecylmaltoside, protein-based nanodiscs, lauryl maltoside-neopentyl glycol, glyco-diosgenin, and amphipols (APols) are the most popular surfactants at the vitrification step. Surfactant exchange is frequently used between MP purification and grid preparation, requiring extensive optimization each time the study of a new MP is undertaken. The variety of both the surfactants and experimental approaches used over the past few years bears witness to the need to continue developing innovative surfactants and optimizing conditions for sample preparation. The possibilities offered by novel APols for EM applications are discussed.
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57
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Fluck EC, Pumroy RA, Moiseenkova-Bell VY. Production and purification of TRPV2 and TRPV5 for structural and functional studies. Methods Enzymol 2021; 653:49-74. [PMID: 34099181 DOI: 10.1016/bs.mie.2021.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transient receptor potential (TRP) vanilloid 2 (TRPV2) and TRP vanilloid 5 (TRPV5) cation channels play an important role in various physiological and pathophysiological processes. The heterologous expression and purification of these channels is critical for functional and structural characterization of these important proteins. Full-length rat TRPV2 and rabbit TRPV5 can both be expressed in Saccharomyces cerevisiae and affinity purified using the 1D4 epitope and antibody to yield pure, functional channels. Further, these channels can be reconstituted into lipid nanodiscs for a more functionally relevant environment. Presented here are protocols for the expression of full-length rat TRPV2 and rabbit TRPV5 in Saccharomyces cerevisiae, their affinity purification, and their reconstitution into nanodiscs for structural and functional studies.
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Affiliation(s)
- Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States.
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58
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Zheng W, Wen H. Predicting lipid and ligand binding sites in TRPV1 channel by molecular dynamics simulation and machine learning. Proteins 2021; 89:966-977. [PMID: 33739482 DOI: 10.1002/prot.26075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/25/2021] [Accepted: 03/15/2021] [Indexed: 11/06/2022]
Abstract
As a key cellular sensor, the TRPV1 channel undergoes a gating transition from a closed state to an open state in response to many physical and chemical stimuli. This transition is regulated by small-molecule ligands including lipids and various agonists/antagonists, but the underlying molecular mechanisms remain obscure. Thanks to recent revolution in cryo-electron microscopy, a growing list of new structures of TRPV1 and other TRPV channels have been solved in complex with various ligands including lipids. Toward elucidating how ligand binding correlates with TRPV1 gating, we have performed extensive molecular dynamics simulations (with cumulative time of 20 μs), starting from high-resolution structures of TRPV1 in both the closed and open states. By comparing between the open and closed state ensembles, we have identified state-dependent binding sites for small-molecule ligands in general and lipids in particular. We further use machine learning to predict top ligand-binding sites as important features to classify the closed vs open states. The predicted binding sites are thoroughly validated by matching homologous sites in all structures of TRPV channels bound to lipids and other ligands, and with previous functional/mutational studies of ligand binding in TRPV1. Taken together, this study has integrated rich structural, dynamic, and functional data to inform future design of small-molecular drugs targeting TRPV1.
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Affiliation(s)
- Wenjun Zheng
- Department of Physics, State University of New York at Buffalo, Buffalo, New York, USA
| | - Han Wen
- Department of Physics, State University of New York at Buffalo, Buffalo, New York, USA
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59
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Goretzki B, Guhl C, Tebbe F, Harder JM, Hellmich UA. Unstructural Biology of TRP Ion Channels: The Role of Intrinsically Disordered Regions in Channel Function and Regulation. J Mol Biol 2021; 433:166931. [PMID: 33741410 DOI: 10.1016/j.jmb.2021.166931] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/02/2021] [Accepted: 03/06/2021] [Indexed: 12/13/2022]
Abstract
The first genuine high-resolution single particle cryo-electron microscopy structure of a membrane protein determined was a transient receptor potential (TRP) ion channel, TRPV1, in 2013. This methodical breakthrough opened up a whole new world for structural biology and ion channel aficionados alike. TRP channels capture the imagination due to the sheer endless number of tasks they carry out in all aspects of animal physiology. To date, structures of at least one representative member of each of the six mammalian TRP channel subfamilies as well as of a few non-mammalian families have been determined. These structures were instrumental for a better understanding of TRP channel function and regulation. However, all of the TRP channel structures solved so far are incomplete since they miss important information about highly flexible regions found mostly in the channel N- and C-termini. These intrinsically disordered regions (IDRs) can represent between a quarter to almost half of the entire protein sequence and act as important recruitment hubs for lipids and regulatory proteins. Here, we analyze the currently available TRP channel structures with regard to the extent of these "missing" regions and compare these findings to disorder predictions. We discuss select examples of intra- and intermolecular crosstalk of TRP channel IDRs with proteins and lipids as well as the effect of splicing and post-translational modifications, to illuminate their importance for channel function and to complement the prevalently discussed structural biology of these versatile and fascinating proteins with their equally relevant 'unstructural' biology.
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Affiliation(s)
- Benedikt Goretzki
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University, Humboldtstrasse 10, 07743 Jena, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Charlotte Guhl
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University, Humboldtstrasse 10, 07743 Jena, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany; TransMED - Mainz Research School of Translational Medicine, Johannes Gutenberg-University, University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Frederike Tebbe
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University, Humboldtstrasse 10, 07743 Jena, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Jean-Martin Harder
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University, Humboldtstrasse 10, 07743 Jena, Germany
| | - Ute A Hellmich
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University, Humboldtstrasse 10, 07743 Jena, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany; TransMED - Mainz Research School of Translational Medicine, Johannes Gutenberg-University, University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany; Cluster of Excellence Balance of the Microverse, Friedrich-Schiller-University, 07743 Jena, Germany.
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60
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Zubcevic L. Preparation of the Transient Receptor Potential Vanilloid 2 (TRPV2) channel for structural studies. Methods Enzymol 2021; 653:21-48. [PMID: 34099173 DOI: 10.1016/bs.mie.2020.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Transient Receptor Potential (TRP) channels play numerous important physiological roles in humans. Notably, they are involved in temperature sensing and regulation, in the proper functioning of immune and cardiac systems, in skin, hair, and bone physiology and in many types of cancer. Because of their physiological significance there has been much interest in elucidating their molecular mechanisms of action. Recent improvements in eukaryotic protein expression and purification techniques and in cryo-electron microscopy (cryo-EM) have greatly facilitated TRP channel studies. The TRP Vanilloid 2 (TRPV2) channel has emerged as particularly amenable to structural studies and its structure has been solved by both X-ray crystallography and by cryo-EM. Here, we provide an overview of demands posed by X-ray crystallography and cryo-EM on protein sample preparation and outline a step-by-step protocol for preparing the TRPV2 protein for structure determination by both of these techniques.
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Affiliation(s)
- Lejla Zubcevic
- Department of Biochemistry and Molecular Biology, The University of Kansas School of Medicine, Kansas City, KS, United States.
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61
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TRPV2: A Cancer Biomarker and Potential Therapeutic Target. DISEASE MARKERS 2020; 2020:8892312. [PMID: 33376561 PMCID: PMC7746447 DOI: 10.1155/2020/8892312] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/05/2020] [Accepted: 10/15/2020] [Indexed: 12/22/2022]
Abstract
The Transient Receptor Potential Vanilloid type-2 (TRPV2) channel exhibits oncogenicity in different types of cancers. TRPV2 is implicated in signaling pathways that mediate cell survival, proliferation, and metastasis. In leukemia and bladder cancer, the oncogenic activity of TRPV2 was linked to alteration of its expression profile. In multiple myeloma patients, TRPV2 overexpression correlated with bone tissue damage and poor prognosis. In prostate cancer, TRPV2 overexpression was associated with the castration-resistant phenotype and metastasis. Loss or inactivation of TRPV2 promoted glioblastoma cell proliferation and increased resistance to CD95-induced apoptotic cell death. TRPV2 overexpression was associated with high relapse-free survival in triple-negative breast cancer, whereas the opposite was found in patients with esophageal squamous cell carcinoma or gastric cancer. Another link was found between TRPV2 expression and either drug-induced cytotoxicity or stemness of liver cancer. Overall, these findings validate TRPV2 as a prime candidate for cancer biomarker and future therapeutic target.
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62
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Abstract
As an important second messenger in adipocytes, calcium ions (Ca2+) are essential in regulating various intracellular signalling pathways that control critical cellular functions. Calcium channels show selective permeability to Ca2+ and facilitate Ca2+ entry into the cytoplasm, which are normally located in the plasmatic and intracellular membranes. The increase of cytosolic Ca2+ modulates a variety of signalling pathways and results in the transcription of target genes that contribute to adipogenesis, a key cellular event includes proliferation and differentiation of adipocyte. In the past decades, the involvement of some Ca2+-permeable ion channels, such as Ca2+ release-activated Ca2+ channels, transient receptor potential channels, voltage-gated calcium channels and others, in adipogenesis has been extensively explored. In the present review, we provided a summary of the expression and contributions of these Ca2+-permeable channels in mediating Ca2+ influxes that drive adipogenesis. Moreover, we discussed their potentials as future therapeutic targets.
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Affiliation(s)
- Mingzhu Zhai
- Huazhong University of Science and Technology Union Shenzhen Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Department of Orthopaedics, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Dazhi Yang
- Huazhong University of Science and Technology Union Shenzhen Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Department of Orthopaedics, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Weihong Yi
- Huazhong University of Science and Technology Union Shenzhen Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Department of Orthopaedics, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Wuping Sun
- Huazhong University of Science and Technology Union Shenzhen Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
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63
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Thompson MJ, Baenziger JE. Ion channels as lipid sensors: from structures to mechanisms. Nat Chem Biol 2020; 16:1331-1342. [PMID: 33199909 DOI: 10.1038/s41589-020-00693-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/08/2020] [Indexed: 12/18/2022]
Abstract
Ion channels play critical roles in cellular function by facilitating the flow of ions across the membrane in response to chemical or mechanical stimuli. Ion channels operate in a lipid bilayer, which can modulate or define their function. Recent technical advancements have led to the solution of numerous ion channel structures solubilized in detergent and/or reconstituted into lipid bilayers, thus providing unprecedented insight into the mechanisms underlying ion channel-lipid interactions. Here, we describe how ion channel structures have evolved to respond to both lipid modulators and lipid activators to control the electrical activities of cells, highlighting diverse mechanisms and common themes.
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Affiliation(s)
- Mackenzie J Thompson
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - John E Baenziger
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
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Zubcevic L. Temperature‐sensitive transient receptor potential vanilloid channels: structural insights into ligand‐dependent activation. Br J Pharmacol 2020; 179:3542-3559. [DOI: 10.1111/bph.15310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/19/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Affiliation(s)
- Lejla Zubcevic
- Department of Biochemistry and Molecular Biology The University of Kansas School of Medicine Kansas City KS USA
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65
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Birch J, Cheruvara H, Gamage N, Harrison PJ, Lithgo R, Quigley A. Changes in Membrane Protein Structural Biology. BIOLOGY 2020; 9:E401. [PMID: 33207666 PMCID: PMC7696871 DOI: 10.3390/biology9110401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022]
Abstract
Membrane proteins are essential components of many biochemical processes and are important pharmaceutical targets. Membrane protein structural biology provides the molecular rationale for these biochemical process as well as being a highly useful tool for drug discovery. Unfortunately, membrane protein structural biology is a difficult area of study due to low protein yields and high levels of instability especially when membrane proteins are removed from their native environments. Despite this instability, membrane protein structural biology has made great leaps over the last fifteen years. Today, the landscape is almost unrecognisable. The numbers of available atomic resolution structures have increased 10-fold though advances in crystallography and more recently by cryo-electron microscopy. These advances in structural biology were achieved through the efforts of many researchers around the world as well as initiatives such as the Membrane Protein Laboratory (MPL) at Diamond Light Source. The MPL has helped, provided access to and contributed to advances in protein production, sample preparation and data collection. Together, these advances have enabled higher resolution structures, from less material, at a greater rate, from a more diverse range of membrane protein targets. Despite this success, significant challenges remain. Here, we review the progress made and highlight current and future challenges that will be overcome.
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Affiliation(s)
- James Birch
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Harish Cheruvara
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Nadisha Gamage
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Peter J. Harrison
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Ryan Lithgo
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, Leicestershire, UK
| | - Andrew Quigley
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
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66
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Cunha MR, Bhardwaj R, Carrel AL, Lindinger S, Romanin C, Parise-Filho R, Hediger MA, Reymond JL. Natural product inspired optimization of a selective TRPV6 calcium channel inhibitor. RSC Med Chem 2020; 11:1032-1040. [PMID: 33479695 PMCID: PMC7513592 DOI: 10.1039/d0md00145g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/18/2020] [Indexed: 12/25/2022] Open
Abstract
Transient receptor potential vanilloid 6 (TRPV6) is a calcium channel implicated in multifactorial diseases and overexpressed in numerous cancers. We recently reported the phenyl-cyclohexyl-piperazine cis-22a as the first submicromolar TRPV6 inhibitor. This inhibitor showed a seven-fold selectivity against the closely related calcium channel TRPV5 and no activity on store-operated calcium channels (SOC), but very significant off-target effects and low microsomal stability. Here, we surveyed analogues incorporating structural features of the natural product capsaicin and identified 3OG, a new oxygenated analog with similar potency against TRPV6 (IC50 = 0.082 ± 0.004 μM) and ion channel selectivity, but with high microsomal stability and very low off-target effects. This natural product-inspired inhibitor does not exhibit any non-specific toxicity effects on various cell lines and is proposed as a new tool compound to test pharmacological inhibition of TRPV6 mediated calcium flux in disease models.
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Affiliation(s)
- Micael Rodrigues Cunha
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , 3012 Bern , Switzerland .
- Department of Pharmacy , University of São Paulo , Prof. Lineu Prestes Avenue 580 , 05508-000 São Paulo , Brazil .
| | - Rajesh Bhardwaj
- Department of Nephrology and Hypertension , University Hospital Bern , Inselspital , 3010 Bern , Switzerland .
| | - Aline Lucie Carrel
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , 3012 Bern , Switzerland .
| | - Sonja Lindinger
- Institute of Biophysics , Johannes Kepler University Linz , Gruberstrasse 40 , 4020 Linz , Austria
| | - Christoph Romanin
- Institute of Biophysics , Johannes Kepler University Linz , Gruberstrasse 40 , 4020 Linz , Austria
| | - Roberto Parise-Filho
- Department of Pharmacy , University of São Paulo , Prof. Lineu Prestes Avenue 580 , 05508-000 São Paulo , Brazil .
| | - Matthias A Hediger
- Department of Nephrology and Hypertension , University Hospital Bern , Inselspital , 3010 Bern , Switzerland .
| | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , 3012 Bern , Switzerland .
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67
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Huffer KE, Aleksandrova AA, Jara-Oseguera A, Forrest LR, Swartz KJ. Global alignment and assessment of TRP channel transmembrane domain structures to explore functional mechanisms. eLife 2020; 9:e58660. [PMID: 32804077 PMCID: PMC7431192 DOI: 10.7554/elife.58660] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022] Open
Abstract
The recent proliferation of published TRP channel structures provides a foundation for understanding the diverse functional properties of this important family of ion channel proteins. To facilitate mechanistic investigations, we constructed a structure-based alignment of the transmembrane domains of 120 TRP channel structures. Comparison of structures determined in the absence or presence of activating stimuli reveals similar constrictions in the central ion permeation pathway near the intracellular end of the S6 helices, pointing to a conserved cytoplasmic gate and suggesting that most available structures represent non-conducting states. Comparison of the ion selectivity filters toward the extracellular end of the pore supports existing hypotheses for mechanisms of ion selectivity. Also conserved to varying extents are hot spots for interactions with hydrophobic ligands, lipids and ions, as well as discrete alterations in helix conformations. This analysis therefore provides a framework for investigating the structural basis of TRP channel gating mechanisms and pharmacology, and, despite the large number of structures included, reveals the need for additional structural data and for more functional studies to establish the mechanistic basis of TRP channel function.
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Affiliation(s)
- Katherine E Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Andrés Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Lucy R Forrest
- Computational Structural Biology Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
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68
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A folding reaction at the C-terminal domain drives temperature sensing in TRPM8 channels. Proc Natl Acad Sci U S A 2020; 117:20298-20304. [PMID: 32747539 DOI: 10.1073/pnas.2004303117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In mammals, temperature-sensitive TRP channels make membrane conductance of cells extremely temperature dependent, allowing the detection of temperature ranging from noxious cold to noxious heat. We progressively deleted the distal carboxyl terminus domain (CTD) of the cold-activated melastatin receptor channel, TRPM8. We found that the enthalpy change associated with channel gating is proportional to the length of the CTD. Deletion of the last 36 amino acids of the CTD transforms TRPM8 into a reduced temperature-sensitivity channel (Q10 ∼4). Exposing the intracellular domain to a denaturing agent increases the energy required to open the channel indicating that cold drives channel gating by stabilizing the folded state of the CTD. Experiments in the presence of an osmoticant agent suggest that channel gating involves a change in solute-inaccessible volume in the CTD of ∼1,900 Å3 This volume matches the void space inside the coiled coil according to the cryogenic electron microscopy structure of TRPM8. The results indicate that a folding-unfolding reaction of a specialized temperature-sensitive structure is coupled to TRPM8 gating.
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69
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Zhou Q, Shi Y, Qi H, Liu H, Wei N, Jiang Y, Wang K. Identification of two natural coumarin enantiomers for selective inhibition of TRPV2 channels. FASEB J 2020; 34:12338-12353. [PMID: 32729134 DOI: 10.1096/fj.201901541rrr] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 01/02/2023]
Abstract
Thermosensitive transient receptor potential vanilloid 2 (thermoTRPV2) is a nonselective Ca2+ -permeable cation channel broadly expressed, and is implicated in the pathology of diseases such as diabetes and pancreatitis. However, the physiological and pharmacological functions of TRPV2 channels have not been extensively investigated because of the absence of specific modulators. In this study, we report a pair of natural coumarin derivative enantiomers (-)-murraxocin (B304-1) and (+)-murraxocin (B304-2) from Murraya exotica for their selective inhibition of TRPV2 channels expressed in HEK293 cells and native TRPV2 currents in differentiated brown adipocytes. Whole-cell patch clamp recordings confirmed the enantiomers B304-1 and B304-2 could selectively inhibit the agonist mediated activation of TRPV2 current with IC50 values of 22.2 ± 7.8 μM and 3.7 ± 0.7 μM, respectively. Molecular docking and site-directed mutagenesis revealed a key residue I600 of TRPV2 critical for the binding of the enantiomers. Furthermore, B304-1 and B304-2 significantly reversed TRPV2 agonist-induced inhibition of mouse brown adipocyte differentiation. Taken together, our identification of two natural coumarin enantiomers provides valuable tools and chemical leads for further elucidation of TRPV2 channel function, and pharmacological modulation of thermoTRPV2 in brown adipocytes may represent a new therapeutic strategy for treatment of energy imbalance or metabolic disorders.
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Affiliation(s)
- Qiqi Zhou
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Yuntao Shi
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Hang Qi
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Huijie Liu
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Ningning Wei
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Yong Jiang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - KeWei Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
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70
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Membrane interactions in drug delivery: Model cell membranes and orthogonal techniques. Adv Colloid Interface Sci 2020; 281:102177. [PMID: 32417568 DOI: 10.1016/j.cis.2020.102177] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/05/2020] [Accepted: 05/07/2020] [Indexed: 01/22/2023]
Abstract
To generate the desired effect in the human body, the active pharmaceutical ingredient usually needs to interact with a receptor located on the cell membrane or inside the cell. Thus, understanding membrane interactions is of great importance when it comes to the development and testing of new drug molecules or new drug delivery systems. Nowadays, there is a tremendous selection of both model cell membranes and of techniques that can be used to characterize interactions between selected model cell membranes and a drug molecule, an excipient, or a drug delivery system. Having such a wide selection of model cell membranes and techniques available makes it sometimes challenging to select the optimal combination for a specific study. Furthermore, it is difficult to compare results obtained using different model cell membranes and techniques, and not all in vitro studies translate as well to an estimation of the in vivo biological activity or understanding of mode of action. This review provides an overview of the available lipid bilayer-based model cell membranes and of the most widely employed techniques for studying membrane interactions. Finally, the need for employing complimentary characterization techniques in order to acquire more reliable and in-depth information is highlighted.
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71
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Zubcevic L. TRP Channels, Conformational Flexibility, and the Lipid Membrane. J Membr Biol 2020; 253:299-308. [DOI: 10.1007/s00232-020-00127-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/11/2020] [Indexed: 02/06/2023]
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Abstract
The TRPV3 channel plays a critical role in skin physiology, and mutations in TRPV3 result in the development of a congenital skin disorder, Olmsted syndrome. Here we describe multiple cryo-electron microscopy structures of human TRPV3 reconstituted into lipid nanodiscs, representing distinct functional states during the gating cycle. The ligand-free, closed conformation reveals well-ordered lipids interacting with the channel and two physical constrictions along the ion conduction pore involving both the extracellular selectivity filter and intracellular helix bundle crossing. Both the selectivity filter and bundle crossing expand upon activation, accompanied by substantial structural rearrangements at the cytoplasmic inter-subunit interface. Transition to the inactivated state involves a secondary structure change of the pore-lining helix, which contains a π-helical segment in the closed and open conformations but becomes entirely α-helical upon inactivation. Together with electrophysiological characterization, structures of TRPV3 in a lipid membrane environment provide unique insights into channel activation and inactivation mechanisms.
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73
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The structure of lipid nanodisc-reconstituted TRPV3 reveals the gating mechanism. Nat Struct Mol Biol 2020; 27:645-652. [PMID: 32572254 DOI: 10.1038/s41594-020-0439-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/24/2020] [Indexed: 12/17/2022]
Abstract
Transient receptor potential vanilloid subfamily member 3 (TRPV3) is a temperature-sensitive cation channel. Previous cryo-EM analyses of TRPV3 in detergent micelles or amphipol proposed that the lower gate opens by α-to-π helical transitions of the nearby S6 helix. However, it remains unclear how physiological lipids are involved in the TRPV3 activation. Here we determined the apo state structure of mouse (Mus musculus) TRPV3 in a lipid nanodisc at 3.3 Å resolution. The structure revealed that lipids bound to the pore domain stabilize the selectivity filter in the narrow state, suggesting that the selectivity filter of TRPV3 affects cation permeation. When the lower gate is closed in nanodisc-reconstituted TRPV3, the S6 helix adopts the π-helical conformation without agonist- or heat-sensitization, potentially stabilized by putative intra-subunit hydrogen bonds and lipid binding. Our findings provide insights into the lipid-associated gating mechanism of TRPV3.
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74
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Yin Y, Lee SY. Current View of Ligand and Lipid Recognition by the Menthol Receptor TRPM8. Trends Biochem Sci 2020; 45:806-819. [PMID: 32532587 DOI: 10.1016/j.tibs.2020.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/26/2020] [Accepted: 05/12/2020] [Indexed: 12/29/2022]
Abstract
Transient receptor potential (TRP) melastatin member 8 (TRPM8), which is a calcium-permeable ion channel, functions as the primary molecular sensor of cold and menthol in humans. Recent cryoelectron microscopy (cryo-EM) studies of TRPM8 have shown distinct structural features in its architecture and domain assembly compared with the capsaicin receptor TRP vanilloid member 1 (TRPV1). Moreover, ligand-bound TRPM8 structures have uncovered unforeseen binding sites for both cooling agonists and membrane lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. These complex structures unveil the molecular basis of cooling agonist sensing by TRPM8 and the allosteric role of PI(4,5)P2 in agonist binding for TRPM8 activation. Here, we review the recent advances in TRPM8 structural biology and investigate the molecular principles governing the distinguishing role of TRPM8 as the evolutionarily conserved menthol receptor.
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Affiliation(s)
- Ying Yin
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA.
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75
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Toledo PFS, Viteri Jumbo LO, Rezende SM, Haddi K, Silva BA, Mello TS, Della Lucia TMC, Aguiar RWS, Smagghe G, Oliveira EE. Disentangling the ecotoxicological selectivity of clove essential oil against aphids and non-target ladybeetles. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137328. [PMID: 32325622 DOI: 10.1016/j.scitotenv.2020.137328] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 06/11/2023]
Abstract
The plant-based biopesticides have been proposed as insect pest control tools that seem to be safer for the environment and human health when compared to synthetic conventional molecules. However, such assumptions are generally made without considering the absence of detrimental effects on sublethally-exposed non-target organisms or showing the physiological basis of the selective action of such botanical products. Thus, by using in silico-based and in vivo toxicological approaches, the present investigation aimed to disentangle the ecotoxicological selectivity of clove, Syzygium aromaticum, essential oil against the aphid Rhopalosiphum maidis and the non-target ladybeetle, Coleomegilla maculata. We also investigated whether the sublethal exposure to clove essential oil would affect the locomotory and predatory abilities of C. maculata. We found that the clove essential oil concentration estimated to kill 95% (LC95: 0.17 μL/cm2) of the aphids was lethal to <18% of C. maculata. Indeed, our in silico results reinforced such differential susceptibility, as it predicted that eugenol and β-caryophyllene (i.e., the clove essential oil major components) bound to three potential molecular targets (i.e., transient receptor potential (TRP) channels, octopamine, and gamma-aminobutyric acid (GABA) receptors) of the aphids but only to the octopamine receptors of the ladybeetles. Additionally, the ladybeetles that were exposure to the clove essential oil exhibited unaffected abilities to locomote and to prey upon R. maidis aphids when compared to unexposed ladybeetles. Thus, by displaying lower toxicity against the ladybeetles, the clove essential oil represents a safer alternative tool to be integrated into programs aiming to manage aphid infestations.
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Affiliation(s)
- Pedro F S Toledo
- Departmento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
| | - Luis O Viteri Jumbo
- Departmento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
| | - Sarah M Rezende
- Departmento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
| | - Khalid Haddi
- Departmento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil; Departamento de Entomologia, Universidade Federal de Lavras, Lavras, MG 37200-000, Brazil
| | - Bruno A Silva
- Departamento de Ciencias Biologicas, Universidade Estadual do Sudoeste da Bahia, Jequié, BA 45206-190, Brazil
| | - Tarcísio S Mello
- Departamento de Ciencias Biologicas, Universidade Estadual do Sudoeste da Bahia, Jequié, BA 45206-190, Brazil
| | | | - Raimundo W S Aguiar
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO 77413-070, Brazil
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent, Belgium
| | - Eugenio E Oliveira
- Departmento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil; Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA.
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76
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van Goor MK, de Jager L, Cheng Y, van der Wijst J. High-resolution structures of transient receptor potential vanilloid channels: Unveiling a functionally diverse group of ion channels. Protein Sci 2020; 29:1569-1580. [PMID: 32232875 PMCID: PMC7314393 DOI: 10.1002/pro.3861] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/21/2020] [Accepted: 03/24/2020] [Indexed: 12/13/2022]
Abstract
Transient receptor potential vanilloid (TRPV) channels are part of the superfamily of TRP ion channels and play important roles in widespread physiological processes including both neuronal and non‐neuronal pathways. Various diseases such as skeletal abnormalities, chronic pain, and cancer are associated with dysfunction of a TRPV channel. In order to obtain full understanding of disease pathogenesis and create opportunities for therapeutic intervention, it is essential to unravel how these channels function at a molecular level. In the past decade, incredible progress has been made in biochemical sample preparation of large membrane proteins and structural biology techniques, including cryo‐electron microscopy. This has resulted in high resolution structures of all TRPV channels, which has provided novel insights into the molecular mechanisms of channel gating and regulation that will be summarized in this review.
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Affiliation(s)
- Mark K van Goor
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Leanne de Jager
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States.,Howard Hughes Medical Institute, University of California, San Francisco, California, United States
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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77
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López-Romero AE, Hernández-Araiza I, Torres-Quiroz F, Tovar-Y-Romo LB, Islas LD, Rosenbaum T. TRP ion channels: Proteins with conformational flexibility. Channels (Austin) 2020; 13:207-226. [PMID: 31184289 PMCID: PMC6602575 DOI: 10.1080/19336950.2019.1626793] [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] [Indexed: 01/02/2023] Open
Abstract
Ion channels display conformational changes in response to binding of their agonists and antagonists. The study of the relationships between the structure and the function of these proteins has witnessed considerable advances in the last two decades using a combination of techniques, which include electrophysiology, optical approaches (i.e. patch clamp fluorometry, incorporation of non-canonic amino acids, etc.), molecular biology (mutations in different regions of ion channels to determine their role in function) and those that have permitted the resolution of their structures in detail (X-ray crystallography and cryo-electron microscopy). The possibility of making correlations among structural components and functional traits in ion channels has allowed for more refined conclusions on how these proteins work at the molecular level. With the cloning and description of the family of Transient Receptor Potential (TRP) channels, our understanding of several sensory-related processes has also greatly moved forward. The response of these proteins to several agonists, their regulation by signaling pathways as well as by protein-protein and lipid-protein interactions and, in some cases, their biophysical characteristics have been studied thoroughly and, recently, with the resolution of their structures, the field has experienced a new boom. This review article focuses on the conformational changes in the pores, concentrating on some members of the TRP family of ion channels (TRPV and TRPA subfamilies) that result in changes in their single-channel conductances, a phenomenon that may lead to fine-tuning the electrical response to a given agonist in a cell.
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Affiliation(s)
- Ana Elena López-Romero
- a Departamento de Neurociencia Cognitiva, División Neurociencias , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico , Mexico
| | - Ileana Hernández-Araiza
- a Departamento de Neurociencia Cognitiva, División Neurociencias , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico , Mexico
| | - Francisco Torres-Quiroz
- b Departamento de Bioquímica y Biología Estructural, División Investigación Básica , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Luis B Tovar-Y-Romo
- c Departamento de Neuropatología Molecular, División Neurociencias , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - León D Islas
- d Departamento de Fisiología, Facultad de Medicina , Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Tamara Rosenbaum
- a Departamento de Neurociencia Cognitiva, División Neurociencias , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico , Mexico
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78
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Yelshanskaya MV, Nadezhdin KD, Kurnikova MG, Sobolevsky AI. Structure and function of the calcium-selective TRP channel TRPV6. J Physiol 2020; 599:2673-2697. [PMID: 32073143 DOI: 10.1113/jp279024] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/03/2020] [Indexed: 12/23/2022] Open
Abstract
Epithelial calcium channel TRPV6 is a member of the vanilloid subfamily of TRP channels that is permeable to cations and highly selective to Ca2+ ; it shows constitutive activity regulated negatively by Ca2+ and positively by phosphoinositol and cholesterol lipids. In this review, we describe the molecular structure of TRPV6 and discuss how its structural elements define its unique functional properties. High Ca2+ selectivity of TRPV6 originates from the narrow selectivity filter, where Ca2+ ions are directly coordinated by a ring of anionic aspartate side chains. Divalent cations Ca2+ and Ba2+ permeate TRPV6 pore according to the knock-off mechanism, while tight binding of Gd3+ to the aspartate ring blocks the channel and prevents Na+ from permeating the pore. The iris-like channel opening is accompanied by an α-to-π helical transition in the pore-lining transmembrane helix S6. As a result of this transition, the intracellular halves of the S6 helices bend and rotate by about 100 deg, exposing different residues to the channel pore in the open and closed states. Channel opening is also associated with changes in occupancy of the transmembrane domain lipid binding sites. The inhibitor 2-aminoethoxydiphenyl borate (2-APB) binds to TRPV6 in a pocket formed by the cytoplasmic half of the S1-S4 transmembrane helical bundle and shifts open-closed channel equilibrium towards the closed state by outcompeting lipids critical for activation. Ca2+ inhibits TRPV6 via binding to calmodulin (CaM), which mediates Ca2+ -dependent inactivation. The TRPV6-CaM complex exhibits 1:1 stoichiometry; one TRPV6 tetramer binds both CaM lobes, which adopt a distinct head-to-tail arrangement. The CaM C-terminal lobe plugs the channel through a unique cation-π interaction by inserting the side chain of lysine K115 into a tetra-tryptophan cage at the ion channel pore intracellular entrance. Recent studies of TRPV6 structure and function described in this review advance our understanding of the role of this channel in physiology and pathophysiology and inform new therapeutic design.
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Affiliation(s)
- Maria V Yelshanskaya
- Department of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, New York, NY, 10032, USA
| | - Kirill D Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, New York, NY, 10032, USA
| | - Maria G Kurnikova
- Chemistry Department, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, New York, NY, 10032, USA
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79
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Production of TRPV2-targeting functional antibody ameliorating dilated cardiomyopathy and muscular dystrophy in animal models. J Transl Med 2020; 100:324-337. [PMID: 31896817 DOI: 10.1038/s41374-019-0363-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 12/28/2022] Open
Abstract
Abnormal Ca2+ handling is essential in the pathophysiology of degenerative muscle disorders, such as dilated cardiomyopathy (DCM) and muscular dystrophy (MD). Transient receptor potential cation channel, subfamily V, member 2 (TRPV2) is a candidate for Ca2+ entry and a potential therapeutic target for degenerative muscle disorders, there are few specific inhibitors for TRPV2. In this study, we produced a monoclonal antibody (designated mAb88-2) and two polyclonal antibodies (pAb591 and pAb592) that selectively recognize TRPV2 from the outside of cells and interact with the turret region of the pore-forming outer gate. These antibodies inhibited Ca2+ influx via TRPV2 in cultured cells and substantially reduced TRPV2 in the plasma membrane via cellular internalization. We evaluated the therapeutic efficacy of the functional antibody in δ-sarcoglycan-deficient hamster (J2N-k) models of DCM and MD and in the 4C30 DCM model of murine heart failure. The intraperitoneal administration of the functional antibody (0.5 mg/kg) for 2 weeks (once a week) prevented the progression of cardiac dysfunction, as evaluated by echocardiography and histological staining, and improved the abnormal Ca2+ handling (high diastolic Ca2+ level and small Ca2+ transient peak) in cardiomyocytes isolated from J2N-k hamsters and prevented skeletal muscle damage. Further, the antibody effectively prevented heart failure in the 4C30 mouse model with end-stage DCM. Interestingly, endogenous TRPV2 that accumulated in the cardiac and skeletal muscle sarcolemma disappeared upon antibody administration. Thus, the newly produced antibodies are capable of ameliorating DCM and MD by promoting the cellular internalization of TRPV2; antibodies specific to human TRPV2 may substantially improve the treatment of patients with degenerative muscle diseases.
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80
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Pumroy RA, Fluck EC, Ahmed T, Moiseenkova-Bell VY. Structural insights into the gating mechanisms of TRPV channels. Cell Calcium 2020; 87:102168. [PMID: 32004816 DOI: 10.1016/j.ceca.2020.102168] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 02/06/2023]
Abstract
Transient Receptor Potential channels from the vanilloid subfamily (TRPV) are a group of cation channels modulated by a variety of endogenous stimuli as well as a range of natural and synthetic compounds. Their roles in human health make them of keen interest, particularly from a pharmacological perspective. However, despite this interest, the complexity of these channels has made it difficult to obtain high resolution structures until recently. With the cryo-EM resolution revolution, TRPV channel structural biology has blossomed to produce dozens of structures, covering every TRPV family member and a variety of approaches to examining channel modulation. Here, we review all currently available TRPV structures and the mechanistic insights into gating that they reveal.
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Affiliation(s)
- Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Tofayel Ahmed
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA.
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81
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Abstract
Cryo electron microscopy (cryo-EM) is a powerful technique that can be used to elucidate the structural architecture of a protein molecule in a physiologically relevant environment. In this method, purified protein is frozen in its aqueous buffer in a thin layer of vitreous ice in which the biological macromolecules are embedded in various orientations. Images of this frozen sample are collected with an electron microscope, and the data is processed using different software algorithms resulting in high-resolution structures of the protein. Proteins in the presence of various ligands or other macromolecular complexes can also be studied by this method. Here, we present a protocol for the purification and vitrification of TRP channels for single particle cryo-EM.
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Affiliation(s)
- Amrita Samanta
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Taylor E T Hughes
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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82
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Abstract
Two decades ago a class of ion channels, hitherto unsuspected, was discovered. In mammals these Transient Receptor Potential channels (TRPs) have not only expanded in number (to 26 functional channels) but also expanded the view of our interface with the physical and chemical environment. Some are heat and cold sensors while others monitor endogenous and/or exogenous chemical signals. Some TRP channels monitor osmotic potential, and others measure cell movement, stretching, and fluid flow. Many TRP channels are major players in nociception and integration of pain signals. One member of the vanilloid sub-family of channels is TRPV6. This channel is highly selective for divalent cations, particularly calcium, and plays a part in general whole-body calcium homeostasis, capturing calcium in the gut from the diet. TRPV6 can be greatly elevated in a number of cancers deriving from epithelia and considerable study has been made of its role in the cancer phenotype where calcium control is dysfunctional. This review compiles and updates recent published work on TRPV6 as a promising drug target in a number of cancers including those afflicting breast, ovarian, prostate and pancreatic tissues.
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Affiliation(s)
- John M Stewart
- Soricimed Biopharma Inc. 18 Botsford Street, Moncton, NB, Canada, E1C 4W7
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83
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Structure-Function Relationship and Physiological Roles of Transient Receptor Potential Canonical (TRPC) 4 and 5 Channels. Cells 2019; 9:cells9010073. [PMID: 31892199 PMCID: PMC7017149 DOI: 10.3390/cells9010073] [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: 11/30/2019] [Revised: 12/24/2019] [Accepted: 12/24/2019] [Indexed: 12/11/2022] Open
Abstract
The study of the structure–function relationship of ion channels has been one of the most challenging goals in contemporary physiology. Revelation of the three-dimensional (3D) structure of ion channels has facilitated our understanding of many of the submolecular mechanisms inside ion channels, such as selective permeability, voltage dependency, agonist binding, and inter-subunit multimerization. Identifying the structure–function relationship of the ion channels is clinically important as well since only such knowledge can imbue potential therapeutics with practical possibilities. In a sense, recent advances in the understanding of the structure–relationship of transient receptor potential canonical (TRPC) channels look promising since human TRPC channels are calcium-permeable, non-selective cation channels expressed in many tissues such as the gastrointestinal (GI) tract, kidney, heart, vasculature, and brain. TRPC channels are known to regulate GI contractility and motility, pulmonary hypertension, right ventricular hypertrophy, podocyte injury, seizure, fear, anxiety-like behavior, and many others. In this article, we tried to elaborate recent findings of Cryo-EM (cryogenic-electron microscopy) based structural information of TRPC 4 and 5 channels and domain-specific functions of the channel, such as G-protein mediated activation mechanism, extracellular modification of the channel, homo/hetero-tetramerization, and pharmacological gating mechanisms.
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84
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Wang Q, Corey RA, Hedger G, Aryal P, Grieben M, Nasrallah C, Baronina A, Pike ACW, Shi J, Carpenter EP, Sansom MSP. Lipid Interactions of a Ciliary Membrane TRP Channel: Simulation and Structural Studies of Polycystin-2. Structure 2019; 28:169-184.e5. [PMID: 31806353 PMCID: PMC7001106 DOI: 10.1016/j.str.2019.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/04/2019] [Accepted: 11/08/2019] [Indexed: 01/08/2023]
Abstract
Polycystin-2 (PC2) is a transient receptor potential (TRP) channel present in ciliary membranes of the kidney. PC2 shares a transmembrane fold with other TRP channels, in addition to an extracellular domain found in TRPP and TRPML channels. Using molecular dynamics (MD) simulations and cryoelectron microscopy we identify and characterize PIP2 and cholesterol interactions with PC2. PC2 is revealed to have a PIP binding site close to the equivalent vanilloid/lipid binding site in the TRPV1 channel. A 3.0-Å structure reveals a binding site for cholesterol on PC2. Cholesterol interactions with the channel at this site are characterized by MD simulations. The two classes of lipid binding sites are compared with sites observed in other TRPs and in Kv channels. These findings suggest PC2, in common with other ion channels, may be modulated by both PIPs and cholesterol, and position PC2 within an emerging model of the roles of lipids in the regulation and organization of ciliary membranes. Lipid interactions of PC2 channels have been explored by MD simulation and cryo-EM PIP2 binds to a site corresponding to the vanilloid/lipid binding site of TRPV1 Cholesterol binds between the S3 and S4 helices and S6 of the adjacent subunit PC2, in common with other channels, may be modulated by PIPs and cholesterol
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Affiliation(s)
- Qinrui Wang
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Prafulla Aryal
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mariana Grieben
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Chady Nasrallah
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Agnese Baronina
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Jiye Shi
- UCB Pharma, 208 Bath Road, Slough SL1 3WE, UK
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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85
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A structural overview of the ion channels of the TRPM family. Cell Calcium 2019; 85:102111. [PMID: 31812825 DOI: 10.1016/j.ceca.2019.102111] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 12/20/2022]
Abstract
The TRPM (transient receptor potential melastatin) family belongs to the superfamily of TRP cation channels. The TRPM subfamily is composed of eight members that are involved in diverse biological functions such as temperature sensing, inflammation, insulin secretion, and redox sensing. Since the first cloning of TRPM1 in 1998, tremendous progress has been made uncovering the function, structure, and pharmacology of this family. Complete structures of TRPM2, TRPM4, and TRPM8, as well as a partial structure of TRPM7, have been determined by cryo-EM, providing insights into their channel assembly, ion permeation, gating mechanisms, and structural pharmacology. Here we summarize the current knowledge about channel structure, emphasizing general features and principles of the structure of TRPM channels discovered since 2017. We also discuss some of the key unresolved issues in the field, including the molecular mechanisms underlying voltage and temperature dependence, as well as the functions of the TRPM channels' C-terminal domains.
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86
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Jara-Oseguera A, Huffer KE, Swartz KJ. The ion selectivity filter is not an activation gate in TRPV1-3 channels. eLife 2019; 8:51212. [PMID: 31724952 PMCID: PMC6887487 DOI: 10.7554/elife.51212] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
Activation of TRPV1 channels in sensory neurons results in opening of a cation permeation pathway that triggers the sensation of pain. Opening of TRPV1 has been proposed to involve two gates that appear to prevent ion permeation in the absence of activators: the ion selectivity filter on the external side of the pore and the S6 helices that line the cytosolic half of the pore. Here we measured the access of thiol-reactive ions across the selectivity filters in rodent TRPV1-3 channels. Although our results are consistent with structural evidence that the selectivity filters in these channels are dynamic, they demonstrate that cations can permeate the ion selectivity filters even when channels are closed. Our results suggest that the selectivity filters in TRPV1-3 channels do not function as activation gates but might contribute to coupling structural rearrangements in the external pore to those in the cytosolic S6 gate.
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Affiliation(s)
- Andrés Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Katherine E Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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87
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Oxidation of methionine residues activates the high-threshold heat-sensitive ion channel TRPV2. Proc Natl Acad Sci U S A 2019; 116:24359-24365. [PMID: 31719194 DOI: 10.1073/pnas.1904332116] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Thermosensitive transient receptor potential (TRP) ion channels detect changes in ambient temperature to regulate body temperature and temperature-dependent cellular activity. Rodent orthologs of TRP vanilloid 2 (TRPV2) are activated by nonphysiological heat exceeding 50 °C, and human TRPV2 is heat-insensitive. TRPV2 is required for phagocytic activity of macrophages which are rarely exposed to excessive heat, but what activates TRPV2 in vivo remains elusive. Here we describe the molecular mechanism of an oxidation-induced temperature-dependent gating of TRPV2. While high concentrations of H2O2 induce a modest sensitization of heat-induced inward currents, the oxidant chloramine-T (ChT), ultraviolet A light, and photosensitizing agents producing reactive oxygen species (ROS) activate and sensitize TRPV2. This oxidation-induced activation also occurs in excised inside-out membrane patches, indicating a direct effect on TRPV2. The reducing agent dithiothreitol (DTT) in combination with methionine sulfoxide reductase partially reverses ChT-induced sensitization, and the substitution of the methionine (M) residues M528 and M607 to isoleucine almost abolishes oxidation-induced gating of rat TRPV2. Mass spectrometry on purified rat TRPV2 protein confirms oxidation of these residues. Finally, macrophages generate TRPV2-like heat-induced inward currents upon oxidation and exhibit reduced phagocytosis when exposed to the TRP channel inhibitor ruthenium red (RR) or to DTT. In summary, our data reveal a methionine-dependent redox sensitivity of TRPV2 which may be an important endogenous mechanism for regulation of TRPV2 activity and account for its pivotal role for phagocytosis in macrophages.
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88
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Ladrón-de-Guevara E, Dominguez L, Rangel-Yescas GE, Fernández-Velasco DA, Torres-Larios A, Rosenbaum T, Islas LD. The Contribution of the Ankyrin Repeat Domain of TRPV1 as a Thermal Module. Biophys J 2019; 118:836-845. [PMID: 31757360 DOI: 10.1016/j.bpj.2019.10.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 10/10/2019] [Accepted: 10/30/2019] [Indexed: 12/22/2022] Open
Abstract
The TRPV1 cation nonselective ion channel plays an essential role in thermosensation and perception of other noxious stimuli. TRPV1 can be activated by low extracellular pH, high temperature, or naturally occurring pungent molecules such as allicin, capsaicin, or resiniferatoxin. Its noxious thermal sensitivity makes it an important participant as a thermal sensor in mammals. However, details of the mechanism of channel activation by increases in temperature remain unclear. Here, we used a combination of approaches to try to understand the role of the ankyrin repeat domain (ARD) in channel behavior. First, a computational modeling approach by coarse-grained molecular dynamics simulation of the whole TRPV1 embedded in a phosphatidylcholine and phosphatidylethanolamine membrane provides insight into the dynamics of this channel domain. Global analysis of the structural ensemble shows that the ARD is a region that sustains high fluctuations during dynamics at different temperatures. We then performed biochemical and thermal stability studies of the purified ARD by the means of circular dichroism and tryptophan fluorescence and demonstrate that this region undergoes structural changes at similar temperatures that lead to TRPV1 activation. Our data suggest that the ARD is a dynamic module and that it may participate in controlling the temperature sensitivity of TRPV1.
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Affiliation(s)
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Mexico City, Mexico
| | | | | | - Alfredo Torres-Larios
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Tamara Rosenbaum
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Leon D Islas
- Facultad de Medicina, Departamento de Fisiología, Mexico City, Mexico.
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89
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Yuan P. Structural biology of thermoTRPV channels. Cell Calcium 2019; 84:102106. [PMID: 31726322 DOI: 10.1016/j.ceca.2019.102106] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/29/2019] [Accepted: 10/29/2019] [Indexed: 11/15/2022]
Abstract
Essential for physiology, transient receptor potential (TRP) channels constitute a large and diverse family of cation channels functioning as cellular sensors responding to a vast array of physical and chemical stimuli. Detailed understanding of the inner workings of TRP channels has been hampered by a lack of atomic structures, though structural biology of TRP channels has been an enthusiastic endeavor since their molecular identification two decades ago. These multi-domain integral membrane proteins, exhibiting complex polymodal gating behavior, have been a challenge for traditional X-ray crystallography, which requires formation of well-ordered protein crystals. X-ray structures remain limited to a few TRP channel proteins to date. Fortunately, recent breakthroughs in single-particle cryo-electron microscopy (cryo-EM) have enabled rapid growth of the number of TRP channel structures, providing tremendous insights into channel gating and regulation mechanisms and serving as foundations for further mechanistic investigations. This brief review focuses on recent exciting developments in structural biology of a subset of TRP channels, the calcium-permeable, non-selective and thermosensitive vanilloid subfamily of TRP channels (TRPV1-4), and the permeation and gating mechanisms revealed by structures.
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Affiliation(s)
- Peng Yuan
- Department of Cell Biology and Physiology, Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, Missouri 63110, USA.
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90
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Alaimo A, Rubert J. The Pivotal Role of TRP Channels in Homeostasis and Diseases throughout the Gastrointestinal Tract. Int J Mol Sci 2019; 20:ijms20215277. [PMID: 31652951 PMCID: PMC6862298 DOI: 10.3390/ijms20215277] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/20/2019] [Accepted: 10/22/2019] [Indexed: 12/12/2022] Open
Abstract
The transient receptor potential (TRP) channels superfamily are a large group of proteins that play crucial roles in cellular processes. For example, these cation channels act as sensors in the detection and transduction of stimuli of temperature, small molecules, voltage, pH, and mechanical constrains. Over the past decades, different members of the TRP channels have been identified in the human gastrointestinal (GI) tract playing multiple modulatory roles. Noteworthy, TRPs support critical functions related to the taste perception, mechanosensation, and pain. They also participate in the modulation of motility and secretions of the human gut. Last but not least, altered expression or activity and mutations in the TRP genes are often related to a wide range of disorders of the gut epithelium, including inflammatory bowel disease, fibrosis, visceral hyperalgesia, irritable bowel syndrome, and colorectal cancer. TRP channels could therefore be promising drug targets for the treatment of GI malignancies. This review aims at providing a comprehensive picture of the most recent advances highlighting the expression and function of TRP channels in the GI tract, and secondly, the description of the potential roles of TRPs in relevant disorders is discussed reporting our standpoint on GI tract–TRP channels interactions.
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Affiliation(s)
- Alessandro Alaimo
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123 Povo (Tn), Italy.
| | - Josep Rubert
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123 Povo (Tn), Italy.
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91
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Lee AG. Interfacial Binding Sites for Cholesterol on TRP Ion Channels. Biophys J 2019; 117:2020-2033. [PMID: 31672270 DOI: 10.1016/j.bpj.2019.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022] Open
Abstract
Transient receptor potential (TRP) channels are members of a large family of ion channels located in membranes rich in cholesterol, some of whose functions are affected by the cholesterol content of the membrane. Here, cholesterol binding to TRPs is studied using a docking procedure that allows the transmembrane surface of a TRP to be swept rapidly for potential binding sites at the interfaces on the two sides of the membrane. Cholesterol docking poses determined in this way match 89% of the cholesterol hemisuccinate molecules in published TRP structures when cholesterol hemisuccinate molecules unlikely to represent typical bound cholesterols are excluded. TRPs are tetrameric, with large clefts at the interfaces between subunits; cholesterol poses are located in hollows, largely within these clefts. Comparison of cholesterol poses with phospholipid binding sites suggests that binding of cholesterol to a TRP need not result in displacement of phospholipid molecules from the TRP surface.
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Affiliation(s)
- Anthony G Lee
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom.
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92
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Pumroy RA, Samanta A, Liu Y, Hughes TE, Zhao S, Yudin Y, Rohacs T, Han S, Moiseenkova-Bell VY. Molecular mechanism of TRPV2 channel modulation by cannabidiol. eLife 2019; 8:48792. [PMID: 31566564 PMCID: PMC6794088 DOI: 10.7554/elife.48792] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 09/27/2019] [Indexed: 12/16/2022] Open
Abstract
Transient receptor potential vanilloid 2 (TRPV2) plays a critical role in neuronal development, cardiac function, immunity, and cancer. Cannabidiol (CBD), the non-psychotropic therapeutically active ingredient of Cannabis sativa, is an activator of TRPV2 and also modulates other transient receptor potential (TRP) channels. Here, we determined structures of the full-length rat TRPV2 channel in apo and CBD-bound states in nanodiscs by cryo-electron microscopy. We show that CBD interacts with TRPV2 through a hydrophobic pocket located between S5 and S6 helices of adjacent subunits, which differs from known ligand and lipid binding sites in other TRP channels. CBD-bound TRPV2 structures revealed that the S4-S5 linker plays a critical role in channel gating upon CBD binding. Additionally, nanodiscs permitted us to visualize two distinct TRPV2 apo states in a lipid environment. Together these results provide a foundation to further understand TRPV channel gating, their divergent physiological functions, and to accelerate structure-based drug design.
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Affiliation(s)
- Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Amrita Samanta
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Yuhang Liu
- Pfizer Research and Development, Groton, United States
| | - Taylor Et Hughes
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Siyuan Zhao
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, United States
| | - Yevgen Yudin
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, United States
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, United States
| | - Seungil Han
- Pfizer Research and Development, Groton, United States
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
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93
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Yang L, Lyman E. Local Enrichment of Unsaturated Chains around the A 2A Adenosine Receptor. Biochemistry 2019; 58:4096-4105. [PMID: 31496229 DOI: 10.1021/acs.biochem.9b00607] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Two 15 μs all-atom simulations of the A2A adenosine receptor were obtained in a ternary mixture of cholesterol, saturated phosphatidylcholine lipids, and unsaturated phosphatidylcholine lipids. An analysis of local lipid solvation is reported on the basis of a Voronoi tessellation of the upper and lower leaflets, identifying first and second solvation shells. The local environments of both the inactive state and the partially active state of the receptor are significantly enriched with unsaturated chains but depleted of cholesterol and saturated chains, relative to the bulk membrane composition. In spite of the local depletion of cholesterol, the partially active receptor binds cholesterol at three locations during the entire simulation trajectory. These long-lived interactions represent the extreme of a very broad distribution of first-solvation shell lipid lifetimes, confounding sharp distinctions between lipid interactions. The broad distributions of lifetimes also make equilibrating the local lipid environment difficult, necessitating long simulation times.
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Affiliation(s)
- Lewen Yang
- Department of Epidemiology , University of Florida , Gainesville , Florida 32610 , United States
| | - Edward Lyman
- Department of Physics and Astronomy , University of Delaware , Newark , Delaware 19716 , United States.,Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
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94
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Duncan AL, Song W, Sansom MSP. Lipid-Dependent Regulation of Ion Channels and G Protein-Coupled Receptors: Insights from Structures and Simulations. Annu Rev Pharmacol Toxicol 2019; 60:31-50. [PMID: 31506010 DOI: 10.1146/annurev-pharmtox-010919-023411] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ion channels and G protein-coupled receptors (GPCRs) are regulated by lipids in their membrane environment. Structural studies combined with biophysical and molecular simulation investigations reveal interaction sites for specific lipids on membrane protein structures. For K channels, PIP2 plays a key role in regulating Kv and Kir channels. Likewise, several recent cryo-EM structures of TRP channels have revealed bound lipids, including PIP2 and cholesterol. Among the pentameric ligand-gated ion channel family, structural and biophysical studies suggest the M4 TM helix may act as a lipid sensor, e.g., forming part of the binding sites for neurosteroids on the GABAA receptor. Structures of GPCRs have revealed multiple cholesterol sites, which may modulate both receptor dynamics and receptor oligomerization. PIP2 also interacts with GPCRs and may modulate their interactions with G proteins. Overall, it is evident that multiple lipid binding sites exist on channels and receptors that modulate their function allosterically and are potential druggable sites.
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Affiliation(s)
- Anna L Duncan
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
| | - Wanling Song
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
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95
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Yin Y, Wu M, Hsu AL, Borschel WF, Borgnia MJ, Lander GC, Lee SY. Visualizing structural transitions of ligand-dependent gating of the TRPM2 channel. Nat Commun 2019; 10:3740. [PMID: 31431622 PMCID: PMC6702222 DOI: 10.1038/s41467-019-11733-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 07/31/2019] [Indexed: 12/20/2022] Open
Abstract
The transient receptor potential melastatin 2 (TRPM2) channel plays a key role in redox sensation in many cell types. Channel activation requires binding of both ADP-ribose (ADPR) and Ca2+. The recently published TRPM2 structures from Danio rerio in the ligand-free and the ADPR/Ca2+-bound conditions represent the channel in closed and open states, which uncovered substantial tertiary and quaternary conformational rearrangements. However, it is unclear how these rearrangements are achieved within the tetrameric channel during channel gating. Here we report the cryo-electron microscopy structures of Danio rerio TRPM2 in the absence of ligands, in complex with Ca2+ alone, and with both ADPR and Ca2+, resolved to ~4.3 Å, ~3.8 Å, and ~4.2 Å, respectively. In contrast to the published results, our studies capture ligand-bound TRPM2 structures in two-fold symmetric intermediate states, offering a glimpse of the structural transitions that bridge the closed and open conformations. The transient receptor potential channel member 2 (TRPM2) ion channel has a function in redox-dependent signaling. Here the authors present the cryo-EM structures of zebrafish TRPM2 in the ligand-free form, with Ca2+ and both ADP-ribose/Ca2+ and observe two-fold symmetric quaternary structure rearrangements in the ligand-bound structures that likely represent intermediate gating states.
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Affiliation(s)
- Ying Yin
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Mengyu Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
| | - William F Borschel
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Mario J Borgnia
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.,Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.
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96
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Abstract
Transient receptor potential (TRP) ion channels are molecular sensors of a large variety of stimuli including temperature, mechanical stress, voltage, small molecules including capsaicin and menthol, and lipids such as phosphatidylinositol 4,5-bisphosphate (PIP2). Since the same TRP channels may respond to different physical and chemical stimuli, they can serve as signal integrators. Many TRP channels are calcium permeable and contribute to Ca2+ homeostasis and signaling. Although the TRP channel family was discovered decades ago, only recently have the structures of many of these channels been solved, largely by cryo-electron microscopy (cryo-EM). Complimentary to cryo-EM, X-ray crystallography provides unique tools to unambiguously identify specific atoms and can be used to study ion binding in channel pores. In this review we describe crystallographic studies of the TRP channel TRPV6. The methodology used in these studies may serve as a template for future structural analyses of different types of TRP and other ion channels.
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Affiliation(s)
- Appu K Singh
- a Department of Biochemistry and Molecular Biophysics , Columbia University , New York , NY
| | - Luke L McGoldrick
- a Department of Biochemistry and Molecular Biophysics , Columbia University , New York , NY.,b Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University , New York , NY
| | - Kei Saotome
- a Department of Biochemistry and Molecular Biophysics , Columbia University , New York , NY
| | - Alexander I Sobolevsky
- a Department of Biochemistry and Molecular Biophysics , Columbia University , New York , NY
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97
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Macikova L, Vyklicka L, Barvik I, Sobolevsky AI, Vlachova V. Cytoplasmic Inter-Subunit Interface Controls Use-Dependence of Thermal Activation of TRPV3 Channel. Int J Mol Sci 2019; 20:E3990. [PMID: 31426314 PMCID: PMC6719031 DOI: 10.3390/ijms20163990] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 02/07/2023] Open
Abstract
The vanilloid transient receptor potential channel TRPV3 is a putative molecular thermosensor widely considered to be involved in cutaneous sensation, skin homeostasis, nociception, and pruritus. Repeated stimulation of TRPV3 by high temperatures above 50 °C progressively increases its responses and shifts the activation threshold to physiological temperatures. This use-dependence does not occur in the related heat-sensitive TRPV1 channel in which responses decrease, and the activation threshold is retained above 40 °C during activations. By combining structure-based mutagenesis, electrophysiology, and molecular modeling, we showed that chimeric replacement of the residues from the TRPV3 cytoplasmic inter-subunit interface (N251-E257) with the homologous residues of TRPV1 resulted in channels that, similarly to TRPV1, exhibited a lowered thermal threshold, were sensitized, and failed to close completely after intense stimulation. Crosslinking of this interface by the engineered disulfide bridge between substituted cysteines F259C and V385C (or, to a lesser extent, Y382C) locked the channel in an open state. On the other hand, mutation of a single residue within this region (E736) resulted in heat resistant channels. We propose that alterations in the cytoplasmic inter-subunit interface produce shifts in the channel gating equilibrium and that this domain is critical for the use-dependence of the heat sensitivity of TRPV3.
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Affiliation(s)
- Lucie Macikova
- Department of Cellular Neurophysiology, Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
- Department of Physiology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | - Lenka Vyklicka
- Department of Cellular Neurophysiology, Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Ivan Barvik
- Division of Biomolecular Physics, Institute of Physics, Faculty of Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Viktorie Vlachova
- Department of Cellular Neurophysiology, Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic.
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98
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Zubcevic L, Lee SY. The role of π-helices in TRP channel gating. Curr Opin Struct Biol 2019; 58:314-323. [PMID: 31378426 DOI: 10.1016/j.sbi.2019.06.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 12/21/2022]
Abstract
Transient Receptor Potential (TRP) channels are a large superfamily of polymodal ion channels, which perform important roles in numerous physiological processes. The architecture of their transmembrane (TM) domains closely resembles that of voltage-gated potassium channels (KV). However, recent cryoEM and crystallographic studies of TRP channels have identified π-helices in functionally important regions, and it is increasingly recognized that they utilize a distinct mechanism of gating that relies on α-to-π secondary structure transitions. Here we review our current understanding of the role of π-helices in TRP channel function and their broader impact on different classes of ion channels.
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Affiliation(s)
- Lejla Zubcevic
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.
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99
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Jiang QX. Structural Variability in the RLR-MAVS Pathway and Sensitive Detection of Viral RNAs. Med Chem 2019; 15:443-458. [PMID: 30569868 DOI: 10.2174/1573406415666181219101613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/23/2018] [Accepted: 12/12/2018] [Indexed: 12/25/2022]
Abstract
Cells need high-sensitivity detection of non-self molecules in order to fight against pathogens. These cellular sensors are thus of significant importance to medicinal purposes, especially for treating novel emerging pathogens. RIG-I-like receptors (RLRs) are intracellular sensors for viral RNAs (vRNAs). Their active forms activate mitochondrial antiviral signaling protein (MAVS) and trigger downstream immune responses against viral infection. Functional and structural studies of the RLR-MAVS signaling pathway have revealed significant supramolecular variability in the past few years, which revealed different aspects of the functional signaling pathway. Here I will discuss the molecular events of RLR-MAVS pathway from the angle of detecting single copy or a very low copy number of vRNAs in the presence of non-specific competition from cytosolic RNAs, and review key structural variability in the RLR / vRNA complexes, the MAVS helical polymers, and the adapter-mediated interactions between the active RLR / vRNA complex and the inactive MAVS in triggering the initiation of the MAVS filaments. These structural variations may not be exclusive to each other, but instead may reflect the adaptation of the signaling pathways to different conditions or reach different levels of sensitivity in its response to exogenous vRNAs.
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Affiliation(s)
- Qiu-Xing Jiang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States
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100
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Hilton JK, Kim M, Van Horn WD. Structural and Evolutionary Insights Point to Allosteric Regulation of TRP Ion Channels. Acc Chem Res 2019; 52:1643-1652. [PMID: 31149807 DOI: 10.1021/acs.accounts.9b00075] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The familiar pungent taste of spicy food, the refreshing taste of mint, and many other physiological phenomena are mediated by transient receptor potential (TRP) ion channels. TRP channels are a superfamily of ion channels that are sensitive to diverse chemical and physical stimuli and play diverse roles in biology. In addition to chemical regulation, some family members also sense common physical stimuli, such as temperature or pressure. Since their discovery and cloning in the 1990s and 2000s, understanding the molecular mechanisms governing TRP channel function and polymodal regulation has been a consistent but challenging goal. Until recently, a general lack of high-resolution TRP channel structures had significantly limited a molecular understanding of their function. In the past few years, a flood of TRP channel structures have been released, made possible primarily by advances in cryo-electron microscopy (cryo-EM). The boon of many structures has unleashed unparalleled insight into TRP channel architecture. Substantive comparative studies between TRP structures provide snapshots of distinct states such as ligand-free, stabilized by chemical agonists, or antagonists, partially illuminating how a given channel opens and closes. However, the now ∼75 TRP channel structures have ushered in surprising outcomes, including a lack of an apparent general mechanism underlying channel opening and closing among family members. Similarly, the structures reveal a surprising diversity in which chemical ligands bind TRP channels. Several TRP channels are activated by temperature changes in addition to ligand binding. Unraveling mechanisms of thermosensation has proven an elusive challenge to the field. Although some studies point to thermosensitive domains in the transmembrane region of the channels, results have sometimes been contradictory and difficult to interpret; in some cases, a domain that proves essential for thermal sensitivity in one context can be entirely removed from the channel without affecting thermosensation in another context. These results are not amenable to simple interpretations and point to allosteric networks of regulation within the channel structure. TRP channels have evolved to be fine-tuned for the needs of a species in its environmental niche, a fact that has been both a benefit and burden in unlocking their molecular features. Functional evolutionary divergence has presented challenges for studying TRP channels, as orthologs from different species can give conflicting experimental results. However, this diversity can also be examined comparatively to decipher the basis for functional differences. As with structural biology, untangling the similarities and differences resulting from evolutionary pressure between species has been a rich source of data guiding the field. This Account will contextualize the existing biochemical and functional data with an eye to evolutionary data and couple these insights with emerging structural biology to better understand the molecular mechanisms behind chemical and physical regulation of TRP channels.
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Affiliation(s)
- Jacob K. Hilton
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- The Biodesign Institute Centers for Personalized Diagnostics and Mechanisms of Evolution, Arizona State University, Tempe, Arizona 85281, United States
| | - Minjoo Kim
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- The Biodesign Institute Centers for Personalized Diagnostics and Mechanisms of Evolution, Arizona State University, Tempe, Arizona 85281, United States
| | - Wade D. Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- The Biodesign Institute Centers for Personalized Diagnostics and Mechanisms of Evolution, Arizona State University, Tempe, Arizona 85281, United States
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