151
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Oliveira ASF, Edsall CJ, Woods CJ, Bates P, Nunez GV, Wonnacott S, Bermudez I, Ciccotti G, Gallagher T, Sessions RB, Mulholland AJ. A General Mechanism for Signal Propagation in the Nicotinic Acetylcholine Receptor Family. J Am Chem Soc 2019; 141:19953-19958. [PMID: 31805762 DOI: 10.1021/jacs.9b09055] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) modulate synaptic activity in the central nervous system. The α7 subtype, in particular, has attracted considerable interest in drug discovery as a target for several conditions, including Alzheimer's disease and schizophrenia. Identifying agonist-induced structural changes underlying nAChR activation is fundamentally important for understanding biological function and rational drug design. Here, extensive equilibrium and nonequilibrium molecular dynamics simulations, enabled by cloud-based high-performance computing, reveal the molecular mechanism by which structural changes induced by agonist unbinding are transmitted within the human α7 nAChR. The simulations reveal the sequence of coupled structural changes involved in driving conformational change responsible for biological function. Comparison with simulations of the α4β2 nAChR subtype identifies features of the dynamical architecture common to both receptors, suggesting a general structural mechanism for signal propagation in this important family of receptors.
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Affiliation(s)
- Ana Sofia F Oliveira
- School of Biochemistry , University of Bristol , Bristol BS8 1DT , United Kingdom
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Christopher J Edsall
- Research Software Engineering, Advanced Computing Research Centre , University of Bristol , Bristol BS1 5QD , United Kingdom
| | - Christopher J Woods
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
- Research Software Engineering, Advanced Computing Research Centre , University of Bristol , Bristol BS1 5QD , United Kingdom
| | - Phil Bates
- Department of Computer Science, Faculty of Engineering , University of Bristol , Bristol BS8 1TR , United Kingdom
- Oracle Corporation, Oracle Cloud Development Centre , Bristol BS2 2JJ , United Kingdom
| | - Gerardo Viedma Nunez
- Oracle Corporation, Oracle Cloud Development Centre , Bristol BS2 2JJ , United Kingdom
| | - Susan Wonnacott
- Department of Biology and Biochemistry , University of Bath , Bath BA2 7AY , United Kingdom
| | - Isabel Bermudez
- Department of Biological and Medical Sciences , Oxford Brookes University , Oxford OX30BP , United Kingdom
| | - Giovanni Ciccotti
- Institute for Applied Computing "Mauro Picone" (IAC), CNR , Via dei Taurini 19 , 00185 Rome , Italy
- School of Physics , University College of Dublin UCD-Belfield , Dublin 4, Ireland
- Università di Roma La Sapienza , Ple. A. Moro 5 , 00185 Roma , Italy
| | - Timothy Gallagher
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Richard B Sessions
- School of Biochemistry , University of Bristol , Bristol BS8 1DT , United Kingdom
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
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152
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Pirayesh E, Stuebler AG, Pandhare A, Jansen M. Delineating the Site of Interaction of the 5-HT 3A Receptor with the Chaperone Protein RIC-3. Biophys J 2019; 118:934-943. [PMID: 31870537 DOI: 10.1016/j.bpj.2019.11.3380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/05/2019] [Accepted: 11/15/2019] [Indexed: 02/07/2023] Open
Abstract
The serotonin type 3A (5-HT3A) receptor is a homopentameric cation-selective member of the pentameric ligand-gated ion channel (pLGIC) superfamily. Members of this superfamily assemble from five subunits, each of which consists of three domains: extracellular (ECD), transmembrane (TMD), and intracellular domain (ICD). Previously, we have demonstrated that the 5-HT3A-ICD is required for the interaction between 5-HT3A and the chaperone protein resistance to inhibitors of choline esterase (RIC-3). Additionally, we have shown that 5-HT3A-ICD fused to maltose-binding protein (MBP) directly interacts with RIC-3, without the involvement of other protein(s). To elucidate the molecular determinants of this interaction, we developed different MBP-fused 5-HT3A-ICD constructs by deleting large segments of its amino acid sequence. We expressed seven engineered ICDs in Escherichia coli and purified them to homogeneity. Using a RIC-3 affinity pull-down assay, the interaction between MBP-5HT3A-ICD constructs and RIC-3 was investigated. In summary, we identify a 24-amino-acid-long segment of the 5-HT3A-ICD as a molecular determinant for the interaction between the 5-HT3A-ICD and RIC-3.
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Affiliation(s)
- Elham Pirayesh
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Antonia G Stuebler
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Akash Pandhare
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas.
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153
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Abstract
In the body, extracellular stimuli produce inositol 1,4,5-trisphosphate (IP3), an intracellular chemical signal that binds to the IP3 receptor (IP3R) to release calcium ions (Ca2+) from the endoplasmic reticulum. In the past 40 years, the wide-ranging functions mediated by IP3R and its genetic defects causing a variety of disorders have been unveiled. Recent cryo-electron microscopy and X-ray crystallography have resolved IP3R structures and begun to integrate with concurrent functional studies, which can explicate IP3-dependent opening of Ca2+-conducting gates placed ∼90 Å away from IP3-binding sites and its regulation by Ca2+. This review highlights recent research progress on the IP3R structure and function. We also propose how protein plasticity within IP3R, which involves allosteric gating and assembly transformations accompanied by rapid and chronic structural changes, would enable it to regulate diverse functions at cellular microdomains in pathophysiological states.
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Affiliation(s)
- Kozo Hamada
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
| | - Katsuhiko Mikoshiba
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
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154
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Dawson A, Trumper P, de Souza JO, Parker H, Jones MJ, Hales TG, Hunter WN. Engineering a surrogate human heteromeric α/β glycine receptor orthosteric site exploiting the structural homology and stability of acetylcholine-binding protein. IUCRJ 2019; 6:1014-1023. [PMID: 31709057 PMCID: PMC6830221 DOI: 10.1107/s205225251901114x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Protein-engineering methods have been exploited to produce a surrogate system for the extracellular neurotransmitter-binding site of a heteromeric human ligand-gated ion channel, the glycine receptor. This approach circumvents two major issues: the inherent experimental difficulties in working with a membrane-bound ion channel and the complication that a heteromeric assembly is necessary to create a key, physiologically relevant binding site. Residues that form the orthosteric site in a highly stable ortholog, acetylcholine-binding protein, were selected for substitution. Recombinant proteins were prepared and characterized in stepwise fashion exploiting a range of biophysical techniques, including X-ray crystallography, married to the use of selected chemical probes. The decision making and development of the surrogate, which is termed a glycine-binding protein, are described, and comparisons are provided with wild-type and homomeric systems that establish features of molecular recognition in the binding site and the confidence that the system is suited for use in early-stage drug discovery targeting a heteromeric α/β glycine receptor.
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Affiliation(s)
- Alice Dawson
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Paul Trumper
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Juliana Oliveira de Souza
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Holly Parker
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Mathew J. Jones
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Tim G. Hales
- Division of Systems Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland
| | - William N. Hunter
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
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155
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Laikowski MM, Reisdorfer F, Moura S. NAChR α4β2 Subtype and their Relation with Nicotine Addiction, Cognition, Depression and Hyperactivity Disorder. Curr Med Chem 2019; 26:3792-3811. [PMID: 29637850 DOI: 10.2174/0929867325666180410105135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/27/2017] [Accepted: 04/05/2018] [Indexed: 01/07/2023]
Abstract
BACKGROUND Neuronal α4β2 nAChRs are receptors involved in the role of neurotransmitters regulation and release, and this ionic channel participates in biological process of memory, learning and attention. This work aims to review the structure and functioning of the α4β2 nAChR emphasizing its role in the treatment of associated diseases like nicotine addiction and underlying pathologies such as cognition, depression and attention-deficit hyperactivity disorder. METHODS The authors realized extensive bibliographic research using the descriptors "Nicotine Receptor α4β2" and "cognition", "depression", "attention-deficit hyperactivity disorder", besides cross-references of the selected articles and after analysis of references in the specific literature. RESULTS As results, it was that found 179 relevant articles presenting the main molecules with affinity to nAChR α4β2 related to the cited diseases. The α4β2 nAChR subtype is a remarkable therapeutic target since this is the most abundant receptor in the central nervous system. CONCLUSION In summary, this review presents perspectives on the pharmacology and therapeutic targeting of α4β2 nAChRs for the treatment of cognition and diseases like nicotine dependence, depression and attention-deficit hyperactivity disorder.
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Affiliation(s)
- Manuela M Laikowski
- Laboratory of Natural and Synthetics Products, University of Caxias do Sul, Caxias do Sul, Brazil
| | - Fávero Reisdorfer
- Laboratory of Drug Development and Quality Control, University Federal of Pampa, Brazil
| | - Sidnei Moura
- Laboratory of Natural and Synthetics Products, University of Caxias do Sul, Caxias do Sul, Brazil
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156
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Murineddu G, Gotti C, Asproni B, Corona P, Martinello K, Plutino S, Fucile S, Temml V, Moretti M, Viani P, Schuster D, Piras S, Deligia F, Pinna GA. Novel N-aryl nicotinamide derivatives: Taking stock on 3,6-diazabicyclo[3.1.1]heptanes as ligands for neuronal acetylcholine receptors. Eur J Med Chem 2019; 180:51-61. [PMID: 31299587 DOI: 10.1016/j.ejmech.2019.06.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 11/20/2022]
Abstract
We designed the synthesis of a small library of 3-substituted-3,6-diazabicyclo[3.1.1]heptanes whose affinity on neuronal nicotinic receptors (nAChRs) was evaluated. Among the synthesized compounds, the 5-(3,6-diazabicyclo[3.1.1]heptane-3-yl)-N-(2-fluorophenyl)nicotinamide 43 proved to be the most interesting compound with α4β2Ki value of 10 pM and a very high α7/α4β2 selectivity. Furthermore, compounds 35, 39 and 43 elicited a selective partial agonist activity for α4β2 nAChR subtype. Finally, in this paper we also report the conclusions on the 3,6-diazabicyclo[3.1.1]heptanes as ligands for nAChRs, resulting from our consolidated structure activity relationship (SAR) studies on this template.
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Affiliation(s)
- Gabriele Murineddu
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy.
| | - Cecilia Gotti
- CNR, Institute of Neuroscience, Via Vanvitelli 32, 20129, Milano, Italy
| | - Battistina Asproni
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy
| | - Paola Corona
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy
| | | | - Simona Plutino
- Dipartimento di Fisiologia e Farmacologia "V. Erspamer", Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Roma, Italy
| | - Sergio Fucile
- IRCCS Neuromed, Via Atinese 18, 86077, Pozzilli, IS, Italy; Dipartimento di Fisiologia e Farmacologia "V. Erspamer", Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Roma, Italy
| | - Veronika Temml
- Insitute of Pharmacy/Pharmacognosy, Center of Molecular Biosciences (CMBI) University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Milena Moretti
- Dept. of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Paola Viani
- Dept. of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Daniela Schuster
- Department of Pharmaceutical Chemistry, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Sandra Piras
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy
| | - Francesco Deligia
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy
| | - Gerard A Pinna
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100, Sassari, Italy
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157
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Hénault CM, Govaerts C, Spurny R, Brams M, Estrada-Mondragon A, Lynch J, Bertrand D, Pardon E, Evans GL, Woods K, Elberson BW, Cuello LG, Brannigan G, Nury H, Steyaert J, Baenziger JE, Ulens C. A lipid site shapes the agonist response of a pentameric ligand-gated ion channel. Nat Chem Biol 2019; 15:1156-1164. [PMID: 31591563 DOI: 10.1038/s41589-019-0369-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 08/21/2019] [Indexed: 12/11/2022]
Abstract
Phospholipids are key components of cellular membranes and are emerging as important functional regulators of different membrane proteins, including pentameric ligand-gated ion channels (pLGICs). Here, we take advantage of the prokaryote channel ELIC (Erwinia ligand-gated ion channel) as a model to understand the determinants of phospholipid interactions in this family of receptors. A high-resolution structure of ELIC in a lipid-bound state reveals a phospholipid site at the lower half of pore-forming transmembrane helices M1 and M4 and at a nearby site for neurosteroids, cholesterol or general anesthetics. This site is shaped by an M4-helix kink and a Trp-Arg-Pro triad that is highly conserved in eukaryote GABAA/C and glycine receptors. A combined approach reveals that M4 is intrinsically flexible and that M4 deletions or disruptions of the lipid-binding site accelerate desensitization in ELIC, suggesting that lipid interactions shape the agonist response. Our data offer a structural context for understanding lipid modulation in pLGICs.
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Affiliation(s)
- Camille M Hénault
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Cedric Govaerts
- Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université libre de Bruxelles, Brussels, Belgium
| | - Radovan Spurny
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Marijke Brams
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | - Joseph Lynch
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | | | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Genevieve L Evans
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Kristen Woods
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ, USA.,Department of Physics, Rutgers University-Camden, Camden, NJ, USA
| | - Benjamin W Elberson
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, TTUHSC, Lubbock, TX, USA
| | - Luis G Cuello
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, TTUHSC, Lubbock, TX, USA
| | - Grace Brannigan
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ, USA.,Department of Physics, Rutgers University-Camden, Camden, NJ, USA
| | - Hugues Nury
- University Grenoble Alpes, CNRS, IBS, Grenoble, France
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - John E Baenziger
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
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158
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Munro L, Ladefoged LK, Padmanathan V, Andersen S, Schiøtt B, Kristensen AS. Conformational Changes in the 5-HT 3A Receptor Extracellular Domain Measured by Voltage-Clamp Fluorometry. Mol Pharmacol 2019; 96:720-734. [PMID: 31582575 DOI: 10.1124/mol.119.116657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/28/2019] [Indexed: 01/13/2023] Open
Abstract
The 5-hydroxytryptamine (5-HT) type 3 receptor is a member of the cysteine (Cys)-loop receptor super family of ligand-gated ion channels in the nervous system and is a clinical target in a range of diseases. The 5-HT3 receptor mediates fast serotonergic neurotransmission by undergoing a series of conformational changes initiated by ligand binding that lead to the rapid opening of an intrinsic cation-selective channel. However, despite the availability of high-resolution structures of a mouse 5-HT3 receptor, many important aspects of the mechanistic basis of 5-HT3 receptor function and modulation by drugs remain poorly understood. In particular, there is little direct evidence for the specific conformational changes predicted to occur during ligand-gated channel activation and desensitization. In the present study, we used voltage-clamp fluorometry (VCF) to measure conformational changes in regions surrounding the orthosteric binding site of the human 5-HT3A (h5-HT3A) receptor during binding of 5-HT and different classes of 5-HT3 receptor ligands. VCF utilizes parallel measurements of receptor currents with photon emission from fluorescent reporter groups covalently attached to specific positions in the receptor structure. Reporter groups that are highly sensitive to the local molecular environment can, in real time, report conformational changes as changes in fluorescence that can be correlated with changes in receptor currents reporting the functional states of the channel. Within the loop C, D, and E regions that surround the orthosteric binding site in the h5-HT3A receptor, we identify positions that are amenable to tagging with an environmentally sensitive reporter group that reports robust fluorescence changes upon 5-HT binding and receptor activation. We use these reporter positions to characterize the effect of ligand binding on the local structure of the orthosteric binding site by agonists, competitive antagonists, and allosterically acting channel activators. We observed that loop C appears to show distinct fluorescence changes for ligands of the same class, while loop D reports similar fluorescence changes for all ligands binding at the orthosteric site. In contrast, the loop E reporter position shows distinct changes for agonists, antagonists, and allosteric compounds, suggesting the conformational changes in this region are specific to ligand function. Interpretation of these results within the framework of current models of 5-HT3 and Cys-loop mechanisms are used to expand the understanding of how ligand binding in Cys-loop receptors relates to channel gating. SIGNIFICANCE STATEMENT: The 5-HT3 receptor is an important ligand-gated ion channel and drug target in the central and peripheral nervous system. Determining how ligand binding induced conformational changes in the receptor is central for understanding the structural mechanisms underlying 5-HT3 receptor function. Here, we employ voltage-gated fluorometry to characterize conformational changes in the extracellular domain of the human 5-HT3 receptor to identify intrareceptor motions during binding of a range of 5-HT3 receptor agonists and antagonists.
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Affiliation(s)
- Lachlan Munro
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Lucy Kate Ladefoged
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Vithushan Padmanathan
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Signe Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Birgit Schiøtt
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Anders S Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
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159
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Fourati Z, Howard RJ, Heusser SA, Hu H, Ruza RR, Sauguet L, Lindahl E, Delarue M. Structural Basis for a Bimodal Allosteric Mechanism of General Anesthetic Modulation in Pentameric Ligand-Gated Ion Channels. Cell Rep 2019; 23:993-1004. [PMID: 29694907 DOI: 10.1016/j.celrep.2018.03.108] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/02/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022] Open
Abstract
Ion channel modulation by general anesthetics is a vital pharmacological process with implications for receptor biophysics and drug development. Functional studies have implicated conserved sites of both potentiation and inhibition in pentameric ligand-gated ion channels, but a detailed structural mechanism for these bimodal effects is lacking. The prokaryotic model protein GLIC recapitulates anesthetic modulation of human ion channels, and it is accessible to structure determination in both apparent open and closed states. Here, we report ten X-ray structures and electrophysiological characterization of GLIC variants in the presence and absence of general anesthetics, including the surgical agent propofol. We show that general anesthetics can allosterically favor closed channels by binding in the pore or favor open channels via various subsites in the transmembrane domain. Our results support an integrated, multi-site mechanism for allosteric modulation, and they provide atomic details of both potentiation and inhibition by one of the most common general anesthetics.
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Affiliation(s)
- Zaineb Fourati
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and UMR 3528 du CNRS, 75015 Paris, France
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics and Science for Life Laboratory, Stockholm University, 17165 Solna, Sweden
| | - Stephanie A Heusser
- Department of Biochemistry and Biophysics and Science for Life Laboratory, Stockholm University, 17165 Solna, Sweden
| | - Haidai Hu
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and UMR 3528 du CNRS, 75015 Paris, France; Sorbonne Universités, UPMC University Paris 6, 75005 Paris, France
| | - Reinis R Ruza
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and UMR 3528 du CNRS, 75015 Paris, France
| | - Ludovic Sauguet
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and UMR 3528 du CNRS, 75015 Paris, France
| | - Erik Lindahl
- Department of Biochemistry and Biophysics and Science for Life Laboratory, Stockholm University, 17165 Solna, Sweden; Swedish e-Science Research Center, KTH Royal Institute of Technology, 11428 Stockholm, Sweden
| | - Marc Delarue
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and UMR 3528 du CNRS, 75015 Paris, France.
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160
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Arias HR, Jin XT, Gallino S, Peng C, Feuerbach D, García-Colunga J, Elgoyhen AB, Drenan RM, Ortells MO. Selectivity of (±)-citalopram at nicotinic acetylcholine receptors and different inhibitory mechanisms between habenular α3β4* and α9α10 subtypes. Neurochem Int 2019; 131:104552. [PMID: 31545995 DOI: 10.1016/j.neuint.2019.104552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/11/2019] [Accepted: 09/20/2019] [Indexed: 01/31/2023]
Abstract
The inhibitory activity of (±)-citalopram on human (h) α3β4, α4β2, and α7 nicotinic acetylcholine receptors (AChRs) was determined by Ca2+ influx assays, whereas its effect on rat α9α10 and mouse habenular α3β4* AChRs by electrophysiological recordings. The Ca2+ influx results clearly establish that (±)-citalopram inhibits (IC50's in μM) hα3β4 AChRs (5.1 ± 1.3) with higher potency than that for hα7 (18.8 ± 1.1) and hα4β2 (19.1 ± 4.2) AChRs. This is in agreement with the [3H]imipramine competition binding results indicating that (±)-citalopram binds to imipramine sites at desensitized hα3β4 with >2-fold higher affinity than that for hα4β2. The electrophysiological, molecular docking, and in silico mutation results indicate that (±)-citalopram competitively inhibits rα9α10 AChRs (7.5 ± 0.9) in a voltage-independent manner by interacting mainly with orthosteric sites, whereas it inhibits a homogeneous population of α3β4* AChRs at MHb (VI) neurons (7.6 ± 1.0) in a voltage-dependent manner by interacting mainly with a luminal site located in the middle of the ion channel, overlapping the imipramine site, which suggests an ion channel blocking mechanism. In conclusion, (±)-citalopram inhibits α3β4 and α9α10 AChRs with higher potency compared to other AChRs but by different mechanisms. (±)-Citalopram also inhibits habenular α3β4*AChRs, supporting the notion that these receptors are important endogenous targets related to their anti-addictive activities.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmacology and Physiology, College of Osteopathic Medicine, Oklahoma State University Center for Health Sciences, Tahlequah, OK, USA.
| | - Xiao-Tao Jin
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Sofía Gallino
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, CONICET, Universidad de Buenos Aires, Argentina
| | - Can Peng
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - Jesús García-Colunga
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, CONICET, Universidad de Buenos Aires, Argentina; Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Ryan M Drenan
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Marcelo O Ortells
- Facultad de Medicina, Universidad de Morón, Morón and CONICET, Argentina.
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161
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Zhang W, Wu H, Zhang R, Fang X, Xu W. Structure and effective charge characterization of proteins by a mobility capillary electrophoresis based method. Chem Sci 2019; 10:7779-7787. [PMID: 31588326 PMCID: PMC6761862 DOI: 10.1039/c9sc02039j] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/02/2019] [Indexed: 12/18/2022] Open
Abstract
Measuring the conformations and effective charges of proteins in solution is critical for investigating protein bioactivity, but their rapid analysis remains a challenging problem. Here we report a mobility capillary electrophoresis (MCE) based method for the rapid analysis of protein stereo-structures and effective charges in different solution environments. With the capability of mixture separation, MCE measures the hydrodynamic radius of a protein through Taylor dispersion analysis and its effective charge through ion mobility analysis. The experimental results acquired from MCE are then utilized to restrain molecular dynamics simulations, so that the most probable conformation of that protein can be obtained. As proof-of-concept demonstrations, the charge states and structures of five proteins were analyzed under close to native environments. The conformation transitions and charge state variations of bovine serum albumin and lysozyme under different pH conditions were also investigated. This method is promising for high-throughput protein analysis, which could potentially be coupled with mass spectrometry for investigating protein stereo-structures and functions in top-down proteomics.
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Affiliation(s)
- Wenjing Zhang
- School of Life Science , Beijing Institute of Technology , No. 5 South Zhongguancun Street, Haidian Dist , Beijing , China .
| | - Haimei Wu
- School of Life Science , Beijing Institute of Technology , No. 5 South Zhongguancun Street, Haidian Dist , Beijing , China .
| | - Rongkai Zhang
- School of Life Science , Beijing Institute of Technology , No. 5 South Zhongguancun Street, Haidian Dist , Beijing , China .
| | - Xiang Fang
- National Institute of Metrology , No. 18, Bei San Huan Dong Lu, Chaoyang Dist , Beijing , China
| | - Wei Xu
- School of Life Science , Beijing Institute of Technology , No. 5 South Zhongguancun Street, Haidian Dist , Beijing , China .
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162
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Lebedev DS, Kryukova EV, Ivanov IA, Egorova NS, Timofeev ND, Spirova EN, Tufanova EY, Siniavin AE, Kudryavtsev DS, Kasheverov IE, Zouridakis M, Katsarava R, Zavradashvili N, Iagorshvili I, Tzartos SJ, Tsetlin VI. Oligoarginine Peptides, a New Family of Nicotinic Acetylcholine Receptor Inhibitors. Mol Pharmacol 2019; 96:664-673. [PMID: 31492697 DOI: 10.1124/mol.119.117713] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/26/2019] [Indexed: 12/28/2022] Open
Abstract
Many peptide ligands of nicotinic acetylcholine receptors (nAChRs) contain a large number of positively charged amino acid residues, a striking example being conotoxins RgIA and GeXIVA from marine mollusk venom, with an arginine content of >30%. To determine whether peptides built exclusively from arginine residues will interact with different nAChR subtypes or with their structural homologs such as the acetylcholine-binding protein and ligand-binding domain of the nAChR α9 subunit, we synthesized a series of R3, R6, R8, and R16 oligoarginines and investigated their activity by competition with radioiodinated α-bungarotoxin, two-electrode voltage-clamp electrophysiology, and calcium imaging. R6 and longer peptides inhibited muscle-type nAChRs, α7 nAChRs, and α3β2 nAChRs in the micromolar range. The most efficient inhibition of ion currents was detected for muscle nAChR by R16 (IC50 = 157 nM) and for the α9α10 subtype by R8 and R16 (IC50 = 44 and 120 nM, respectively). Since the R8 affinity for other tested nAChRs was 100-fold lower, R8 appears to be a selective antagonist of α9α10 nAChR. For R8, the electrophysiological and competition experiments indicated the existence of two distinct binding sites on α9α10 nAChR. Since modified oligoarginines and other cationic molecules are widely used as cell-penetrating peptides, we studied several cationic polymers and demonstrated their nAChR inhibitory activity. SIGNIFICANT STATEMENT: By using radioligand analysis, electrophysiology, and calcium imaging, we found that oligoarginine peptides are a new group of inhibitors for muscle nicotinic acetylcholine receptors (nAChRs) and some neuronal nAChRs, the most active being those with 16 and 8 Arg residues. Such compounds and other cationic polymers are cell-penetrating tools for drug delivery, and we also demonstrated the inhibition of nAChRs for several of the latter. Possible positive and negative consequences of such an action should be taken into account.
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Affiliation(s)
- Dmitry S Lebedev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Elena V Kryukova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Igor A Ivanov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Natalia S Egorova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Nikita D Timofeev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ekaterina N Spirova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Elizaveta Yu Tufanova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Andrei E Siniavin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Denis S Kudryavtsev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Igor E Kasheverov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Marios Zouridakis
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ramaz Katsarava
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Nino Zavradashvili
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ia Iagorshvili
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Socrates J Tzartos
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Victor I Tsetlin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
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163
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Gharpure A, Teng J, Zhuang Y, Noviello CM, Walsh RM, Cabuco R, Howard RJ, Zaveri NT, Lindahl E, Hibbs RE. Agonist Selectivity and Ion Permeation in the α3β4 Ganglionic Nicotinic Receptor. Neuron 2019; 104:501-511.e6. [PMID: 31488329 DOI: 10.1016/j.neuron.2019.07.030] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/01/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022]
Abstract
Nicotinic acetylcholine receptors are pentameric ion channels that mediate fast chemical neurotransmission. The α3β4 nicotinic receptor subtype forms the principal relay between the central and peripheral nervous systems in the autonomic ganglia. This receptor is also expressed focally in brain areas that affect reward circuits and addiction. Here, we present structures of the α3β4 nicotinic receptor in lipidic and detergent environments, using functional reconstitution to define lipids appropriate for structural analysis. The structures of the receptor in complex with nicotine, as well as the α3β4-selective ligand AT-1001, complemented by molecular dynamics, suggest principles of agonist selectivity. The structures further reveal much of the architecture of the intracellular domain, where mutagenesis experiments and simulations define residues governing ion conductance.
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Affiliation(s)
- Anant Gharpure
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jinfeng Teng
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yuxuan Zhuang
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna 17121, Sweden
| | - Colleen M Noviello
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Richard M Walsh
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rico Cabuco
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna 17121, Sweden
| | | | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna 17121, Sweden; Department of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, Solna 17121, Sweden
| | - Ryan E Hibbs
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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164
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Uchikawa E, Choi E, Shang G, Yu H, Bai XC. Activation mechanism of the insulin receptor revealed by cryo-EM structure of the fully liganded receptor-ligand complex. eLife 2019; 8:e48630. [PMID: 31436533 PMCID: PMC6721835 DOI: 10.7554/elife.48630] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/21/2019] [Indexed: 12/12/2022] Open
Abstract
Insulin signaling controls metabolic homeostasis. Here, we report the cryo-EM structure of full-length insulin receptor (IR) and insulin complex in the active state. This structure unexpectedly reveals that maximally four insulins can bind the 'T'-shaped IR dimer at four distinct sites related by 2-fold symmetry. Insulins 1 and 1' bind to sites 1 and 1', formed by L1 of one IR protomer and α-CT and FnIII-1 of the other. Insulins 2 and 2' bind to sites 2 and 2' on FnIII-1 of each protomer. Mutagenesis and cellular assays show that both sites 1 and 2 are required for optimal insulin binding and IR activation. We further identify a homotypic FnIII-2-FnIII-2 interaction in mediating the dimerization of membrane proximal domains in the active IR dimer. Our results indicate that binding of multiple insulins at two distinct types of sites disrupts the autoinhibited apo-IR dimer and stabilizes the active dimer.
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Affiliation(s)
- Emiko Uchikawa
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Eunhee Choi
- Department of PharmacologyHoward Hughes Medical Institute, University of Texas Southwestern Medical CenterDallasUnited States
| | - Guijun Shang
- Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Hongtao Yu
- Department of PharmacologyHoward Hughes Medical Institute, University of Texas Southwestern Medical CenterDallasUnited States
| | - Xiao-chen Bai
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasUnited States
- Department of Cell BiologyUniversity of Texas Southwestern Medical CenterDallasUnited States
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165
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Pérez de Vega MJ, Fernandez-Mendivil C, de la Torre Martínez R, González-Rodríguez S, Mullet J, Sala F, Sala S, Criado M, Moreno-Fernández S, Miguel M, Fernández-Carvajal A, Ferrer-Montiel A, López MG, González-Muñiz R. 1-(2',5'-Dihydroxyphenyl)-3-(2-fluoro-4-hydroxyphenyl)-1-propanone (RGM079): A Positive Allosteric Modulator of α7 Nicotinic Receptors with Analgesic and Neuroprotective Activity. ACS Chem Neurosci 2019; 10:3900-3909. [PMID: 31322853 DOI: 10.1021/acschemneuro.9b00364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acetylcholine α7 nicotinic receptors are widely expressed in the brain, where they are involved in the central processing of pain as well as in neuropsychiatric, neurodegenerative, and inflammatory processes. Positive allosteric modulators (PAMs) show the advantage of allowing the selective regulation of different subtypes of acetylcholine receptors without directly interacting with the agonist binding site. Here, we report the preparation and biological activity of a fluoro-containing compound, 1-(2',5'-dihydroxyphenyl)-3-(2-fluoro-4-hydroxyphenyl)-1-propanone (8, RGM079), that behaves as a potent PAM of the α7 receptors and has a balanced pharmacokinetic profile and antioxidant properties comparable or even higher than well-known natural polyphenols. In addition, compound RGM079 shows neuroprotective properties in Alzheimer's disease (AD)-toxicity related models. Thus, it causes a concentration-dependent neuroprotective effect against the toxicity induced by okadaic acid (OA) in the human neuroblastoma cell line SH-SY5Y. Similarly, in primary cultures of rat cortical neurons, RGM079 is able to restore the cellular viability after exposure to OA and amyloid peptide Aβ1-42, with cell death almost completely prevented at 10 and 30 μM, respectively. Finally, compound RGM079 shows in vivo analgesic activity in the complete Freund's adjuvant (CFA)-induced paw inflammation model after intraperitoneal administration.
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Affiliation(s)
| | - Cristina Fernandez-Mendivil
- Instituto Teófilo Hernando, Department of Pharmacology, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, Madrid 28029, Spain
| | - Roberto de la Torre Martínez
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Avenida de la Universidad s/n, Elche, Alicante 03202, Spain
| | - Sara González-Rodríguez
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Avenida de la Universidad s/n, Elche, Alicante 03202, Spain
| | - José Mullet
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d’Alacant, Alicante 03500, Spain
| | - Francisco Sala
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d’Alacant, Alicante 03500, Spain
| | - Salvador Sala
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d’Alacant, Alicante 03500, Spain
| | - Manuel Criado
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d’Alacant, Alicante 03500, Spain
| | - Silvia Moreno-Fernández
- Instituto de Investigación en Ciencias de la Alimentación (CSIC-UAM), C/Nicolás Cabrera 9, Madrid 28049, Spain
| | - Marta Miguel
- Instituto de Investigación en Ciencias de la Alimentación (CSIC-UAM), C/Nicolás Cabrera 9, Madrid 28049, Spain
| | - Asia Fernández-Carvajal
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Avenida de la Universidad s/n, Elche, Alicante 03202, Spain
| | - Antonio Ferrer-Montiel
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Avenida de la Universidad s/n, Elche, Alicante 03202, Spain
| | - Manuela G. López
- Instituto Teófilo Hernando, Department of Pharmacology, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, Madrid 28029, Spain
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166
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Alamiddine Z, Selvam B, Graton J, Laurent AD, Landagaray E, Lebreton J, Mathé-Allainmat M, Thany SH, Le Questel JY. Binding of Sulfoxaflor to Aplysia californica-AChBP: Computational Insights from Multiscale Approaches. J Chem Inf Model 2019; 59:3755-3769. [PMID: 31361951 DOI: 10.1021/acs.jcim.9b00272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Structural features and binding properties of sulfoxaflor (SFX) with Ac-AChBP, the surrogate of the insect nAChR ligand binding domain (LBD), are reported herein using various complementary molecular modeling approaches (QM, molecular docking, molecular dynamics, and QM/QM'). The different SFX stereoisomers show distinct behaviors in terms of binding and interactions with Ac-AChBP. Molecular docking and Molecular Dynamics (MD) simulations highlight the specific intermolecular contacts involved in the binding of the different SFX isomers and the relative contribution of the SFX functional groups. QM/QM' calculations provide further insights and a significant refinement of the geometric and energetic contributions of the various residues leading to a preference for the SS and RR stereoisomers. Notable differences in terms of binding interactions are pointed out for the four stereoisomers. The results point out the induced fit of the Ac-AChBP binding site according to the SFX stereoisomer. In this process, the water molecules-mediated contacts play a key role, their energetic contribution being among the most important for the various stereoisomers. In all cases, the interaction with Trp147 is the major binding component, through CH···π and π···π interactions. This study provides a rationale for the binding of SFX to insect nAChR, in particular with respect to the new class of sulfoximine-based insect nAChR competitive modulators, and points out the requirements of various levels of theory for an accurate description of ligand-receptor interactions.
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Affiliation(s)
- Zakaria Alamiddine
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
| | - Balaji Selvam
- University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Roger Adams Laboratory , Urbana , Illinois 61801 , United States
| | - Jérôme Graton
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
| | - Adèle D Laurent
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
| | - Elodie Landagaray
- Université d'Orléans, Institut de Chimie Organique Analytique, UMR CNRS 7311 , rue de Chartres , BP 6759, Orléans 45067 Cedex 2 , France
| | - Jacques Lebreton
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
| | - Monique Mathé-Allainmat
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
| | - Steeve H Thany
- Université d'Orléans, Laboratoire Biologie des Ligneux et des Grandes Cultures, USC INRA 1328 . Rue de Chartres , BP 6759, Orléans 45067 Cedex 2 , France
| | - Jean-Yves Le Questel
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes , 2 rue de la Houssinière , BP 92208, Nantes F-44322 , France
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167
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Pandhare A, Pirayesh E, Stuebler AG, Jansen M. Triple arginines as molecular determinants for pentameric assembly of the intracellular domain of 5-HT 3A receptors. J Gen Physiol 2019; 151:1135-1145. [PMID: 31409663 PMCID: PMC6719409 DOI: 10.1085/jgp.201912421] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/15/2019] [Indexed: 11/20/2022] Open
Abstract
Serotonin type 3A receptors are homopentameric ligand-gated ion channels that are thought to assemble via interactions involving the subunits’ extracellular and transmembrane domains. Pandhare et al. reveal that channel assembly is also determined by three arginine residues in the receptor’s intracellular domain. Serotonin type 3 receptors (5-HT3Rs) are cation-conducting pentameric ligand-gated ion channels and members of the Cys-loop superfamily in eukaryotes. 5-HT3Rs are found in the peripheral and central nervous system, and they are targets for drugs used to treat anxiety, drug dependence, and schizophrenia, as well as chemotherapy-induced and postoperative nausea and emesis. Decades of research of Cys-loop receptors have identified motifs in both the extracellular and transmembrane domains that mediate pentameric assembly. Those efforts have largely ignored the most diverse domain of these channels, the intracellular domain (ICD). Here we identify molecular determinants within the ICD of serotonin type 3A (5-HT3A) subunits for pentameric assembly by first identifying the segments contributing to pentamerization using deletion constructs of, and finally by making defined amino acid substitutions within, an isolated soluble ICD. Our work provides direct experimental evidence for the contribution of three intracellular arginines, previously implicated in governing the low conductance of 5-HT3ARs, in structural features such as pentameric assembly.
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Affiliation(s)
- Akash Pandhare
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Elham Pirayesh
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Antonia G Stuebler
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX
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169
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Arias HR, Ortells MO, Feuerbach D, Burgos V, Paz C. Alkaloids Purified from Aristotelia chilensis Inhibit the Human α3β4 Nicotinic Acetylcholine Receptor with Higher Potencies Compared with the Human α4β2 and α7 Subtypes. JOURNAL OF NATURAL PRODUCTS 2019; 82:1953-1960. [PMID: 31276409 DOI: 10.1021/acs.jnatprod.9b00314] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The alkaloids aristoteline (1), aristoquinoline (2), and aristone (3) were purified from the leaves of the Maqui tree Aristotelia chilensis and chemically characterized by NMR spectroscopy. The pharmacological activity of these natural compounds was evaluated on human (h) α3β4, α4β2, and α7 nicotinic acetylcholine receptors (AChRs) by Ca2+ influx measurements. The results suggest that these alkaloids do not have agonistic, but inhibitory, activity on each receptor subtype. The obtained IC50 values indicate the following receptor selectivity: hα3β4 > hα4β2 ≫ hα7. In the particular case of hα3β4 AChRs, 1 (0.40 ± 0.20 μM) and 2 (0.96 ± 0.38 μM) show higher potencies compared with 3 (167 ± 3 μM). Molecular docking and structure-activity relationship results indicate that ligand lipophilicity is important for the interaction with the luminal site located close to the cytoplasmic side of the hα3β4 ion channel between positions -2' and -4'. Compound 1 could be used as a molecular scaffold for the development of more potent noncompetitive inhibitors with higher selectivity for the hα3β4 AChR that could serve for novel addiction and depression therapies.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Science, School of Pharmacy , American University of Health Sciences , Signal Hill , California 90755 , United States
| | - Marcelo O Ortells
- Facultad de Medicina , Universidad de Morón , and CONICET, 1708 Morón , Buenos Aires , Argentina
| | - Dominik Feuerbach
- Novartis Institutes for Biomedical Research , 4001 Basel , Switzerland
| | - Viviana Burgos
- Laboratory of Natural Products and Drug Discovery, Department of Basic Sciences , Universidad de La Frontera , 4780000 Temuco , Chile
| | - Cristian Paz
- Laboratory of Natural Products and Drug Discovery, Department of Basic Sciences , Universidad de La Frontera , 4780000 Temuco , Chile
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170
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Minimal Structural Changes Determine Full and Partial Nicotinic Receptor Agonist Activity for Nicotine Analogues. Molecules 2019; 24:molecules24152684. [PMID: 31344816 PMCID: PMC6695845 DOI: 10.3390/molecules24152684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022] Open
Abstract
Neuronal α4β2 nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels (LGIC) that have been implicated in nicotine addiction, reward, cognition, pain disorders, anxiety, and depression. Nicotine has been widely used as a template for the synthesis of ligands that prefer α4β2 nAChRs subtypes. The most important therapeutic use for α4β2 nAChRs is as replacement therapy for smoking cessation and withdrawal and the most successful therapeutic ligands are partial agonists. In this case, we use the N-methylpyrrolidine moiety of nicotine to design and synthesize new α4β2 nicotinic derivatives, coupling the pyrrolidine moiety to an aromatic group by introducing an ether-bonded functionality. Meta-substituted phenolic derivatives were used for these goals. Radioligand binding assays were performed on clonal cell lines of hα4β2 nAChR and two electrode voltage-clamp experiments were used for functional assays. Molecular docking was performed in the open state of the nAChR in order to rationalize the agonist activity shown by our compounds.
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171
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Untangling Direct and Domain-Mediated Interactions Between Nicotinic Acetylcholine Receptors in DHA-Rich Membranes. J Membr Biol 2019; 252:385-396. [PMID: 31321460 DOI: 10.1007/s00232-019-00079-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/04/2019] [Indexed: 02/01/2023]
Abstract
At the neuromuscular junction (NMJ), the nicotinic acetylcholine receptor (nAChR) self-associates to give rise to rapid muscle movement. While lipid domains have maintained nAChR aggregates in vitro, their specific roles in nAChR clustering are currently unknown. In the present study, we carried out coarse-grained molecular dynamics simulations (CG-MD) of 1-4 nAChR molecules in two membrane environments: one mixture containing domain-forming, homoacidic lipids, and a second mixture consisting of heteroacidic lipids. Spontaneous dimerization of nAChRs was up to ten times more likely in domain-forming membranes; however, the effect was not significant in four-protein systems, suggesting that lipid domains are less critical to nAChR oligomerization when protein concentration is higher. With regard to lipid preferences, nAChRs consistently partitioned into liquid-disordered domains occupied by the omega-3 ([Formula: see text]-3) fatty acid, docosahexaenoic acid (DHA); enrichment of DHA boundary lipids increased with protein concentration, particularly in homoacidic membranes. This result suggests dimer formation blocks access of saturated chains and cholesterol, but not polyunsaturated chains, to boundary lipid sites.
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172
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Suresh A, Hung A. Structural effects of divalent calcium cations on the α7 nicotinic acetylcholine receptor: A molecular dynamics simulation study. Proteins 2019; 87:992-1005. [PMID: 31228282 DOI: 10.1002/prot.25761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 05/27/2019] [Accepted: 06/15/2019] [Indexed: 12/11/2022]
Abstract
The α7 subtype of neuronal nicotinic acetylcholine receptor (nAChR) is a ligand-gated ion channel protein that is vital to various neurological functions, including modulation of neurotransmitter release. A relatively high concentration of extracellular Ca2+ in the neuronal environment is likely to exert substantial structural and functional influence on nAChRs, which may affect their interactions with agonists and antagonists. In this work, we employed atomistic molecular dynamics (MD) simulations to examine the effects of elevated Ca2+ on the structure and dynamics of α7 nAChR embedded in a model phospholipid bilayer. Our results suggest that the presence of Ca2+ in the α7 nAChR environment results in closure of loop C-in the extracellular ligand-binding domain, a motion normally associated with agonist binding and receptor activation. Elevated Ca2+ also alters the conformation of key regions of the receptor, including the inter-helical loops, pore-lining helices and the "gate" residues, and causes partial channel opening in the absence of an agonist, leading to an attendant reduction in the free energy of Ca2+ permeation through the pore as elucidated by umbrella sampling simulations. Overall, the structural and permeability changes in α7 nAChR suggest that elevated Ca2+ induces a partially activated receptor state that is distinct from both the resting and the agonist-activated states. These results are consistent with the notion that divalent ions can serve as a potentiator of nAChRs, resulting in a higher rate of receptor activation (and subsequent desensitization) in the presence of agonists, with possible implications for diseases involving calcium dysregulation.
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Affiliation(s)
- Abishek Suresh
- School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Andrew Hung
- School of Science, RMIT University, Melbourne, Victoria, Australia
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Li R, Li X, Jiang J, Tian Y, Liu D, Zhangsun D, Fu Y, Wu Y, Luo S. Interaction of rat α9α10 nicotinic acetylcholine receptor with α-conotoxin RgIA and Vc1.1: Insights from docking, molecular dynamics and binding free energy contributions. J Mol Graph Model 2019; 92:55-64. [PMID: 31330438 DOI: 10.1016/j.jmgm.2019.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 06/25/2019] [Accepted: 06/27/2019] [Indexed: 12/12/2022]
Abstract
The α9α10 nicotinic acetylcholine receptor (nAChR) is an effective therapeutic target for neuropathic pain. α-Conotoxin RgIA and Vc1.1 are two well-known peptides blocking α9α10 nAChR potently and selectively, which have been extensively investigated as drug candidates. Several key residues were established in previous experimental research. However, the mechanism of the specific interaction still needs to be elucidated in more detail. In this work, we explored the interaction mechanism between RgIA/Vc1.1 and rat α9α10 nAChR using docking and molecular dynamics (MD) simulations. Energy and network analysis programs were used to reveal key residues responsible for their interaction. Our results indicated that the most critical residues were in accord with previous studies. Importantly, several novel residues, including Tyr95, Trp151 in α9 (+)α10 (-) interface as well as Tyr196, Arg59in α10 (+)α9 (-) interface, were found in our models. Furthermore, we analyzed noncovalent interaction energies between RgIA/Vc1.1 and rat α9α10 nAChR. The results showed that three negatively charged residues (Glu197 in α10 subunit, Asp168 in α9 subunit and Asp205 in α10 subunit) were involved in the interaction between RgIA and rat α9α10 nAChR. In contrast, the interaction between Vc1.1 and rat α9α10 nAChR was mediated by the positively charged residues Arg59, Arg81 in α9 (-) subunit. These findings provided further insights into the molecular mechanisms of interaction between RgIA and Vc1.1 and rat α9α10 nAChR.
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Affiliation(s)
- Rui Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Xincan Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Jiemei Jiang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Yuanyuan Tian
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Danrui Liu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Donting Zhangsun
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Ying Fu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou, Hainan, 570228, China.
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174
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Oliveira ASF, Shoemark DK, Campello HR, Wonnacott S, Gallagher T, Sessions RB, Mulholland AJ. Identification of the Initial Steps in Signal Transduction in the α4β2 Nicotinic Receptor: Insights from Equilibrium and Nonequilibrium Simulations. Structure 2019; 27:1171-1183.e3. [PMID: 31130483 DOI: 10.1016/j.str.2019.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/28/2019] [Accepted: 04/10/2019] [Indexed: 02/02/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) modulate synaptic transmission in the nervous system. These receptors have emerged as therapeutic targets in drug discovery for treating several conditions, including Alzheimer's disease, pain, and nicotine addiction. In this in silico study, we use a combination of equilibrium and nonequilibrium molecular dynamics simulations to map dynamic and structural changes induced by nicotine in the human α4β2 nAChR. They reveal a striking pattern of communication between the extracellular binding pockets and the transmembrane domains (TMDs) and show the sequence of conformational changes associated with the initial steps in this process. We propose a general mechanism for signal transduction for Cys-loop receptors: the mechanistic steps for communication proceed firstly through loop C in the principal subunit, and are subsequently transmitted, gradually and cumulatively, to loop F of the complementary subunit, and then to the TMDs through the M2-M3 linker.
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Affiliation(s)
- A Sofia F Oliveira
- School of Biochemistry, University of Bristol, Bristol BS8 1DT, UK; Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | | | - Hugo Rego Campello
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Susan Wonnacott
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Timothy Gallagher
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | | | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
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175
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Norleans J, Wang J, Kuryatov A, Leffler A, Doebelin C, Kamenecka TM, Lindstrom J. Discovery of an intrasubunit nicotinic acetylcholine receptor-binding site for the positive allosteric modulator Br-PBTC. J Biol Chem 2019; 294:12132-12145. [PMID: 31221718 DOI: 10.1074/jbc.ra118.006253] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 06/19/2019] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptor (nAChR) ligands that lack agonist activity but enhance activation in the presence of an agonist are called positive allosteric modulators (PAMs). nAChR PAMs have therapeutic potential for the treatment of nicotine addiction and several neuropsychiatric disorders. PAMs need to be selectively targeted toward certain nAChR subtypes to tap this potential. We previously discovered a novel PAM, (R)-7-bromo-N-(piperidin-3-yl)benzo[b]thiophene-2-carboxamide (Br-PBTC), which selectively potentiates the opening of α4β2*, α2β2*, α2β4*, and (α4β4)2α4 nAChRs and reactivates some of these subtypes when desensitized (* indicates the presence of other subunits). We located the Br-PBTC-binding site through mutagenesis and docking in α4. The amino acids Glu-282 and Phe-286 near the extracellular domain on the third transmembrane helix were found to be crucial for Br-PBTC's PAM effect. E282Q abolishes Br-PBTC potentiation. Using (α4E282Qβ2)2α5 nAChRs, we discovered that the trifluoromethylated derivatives of Br-PBTC can potentiate channel opening of α5-containing nAChRs. Mutating Tyr-430 in the α5 M4 domain changed α5-selectivity among Br-PBTC derivatives. There are two kinds of α4 subunits in α4β2 nAChRs. Primary α4 forms an agonist-binding site with another β2 subunit. Accessory α4 forms an agonist-binding site with another α4 subunit. The pharmacological effect of Br-PBTC depends both on its own and agonists' occupancy of primary and accessory α4 subunits. Br-PBTC reactivates desensitized (α4β2)2α4 nAChRs. Its full efficacy requires intact Br-PBTC sites in at least one accessory and one primary α4 subunit. PAM potency increases with higher occupancy of the agonist sites. Br-PBTC and its derivatives should prove useful as α subunit-selective nAChR PAMs.
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Affiliation(s)
- Jack Norleans
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jingyi Wang
- Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712
| | - Alexander Kuryatov
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Abba Leffler
- Neuroscience Graduate Program, Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10010
| | - Christelle Doebelin
- Department of Molecular Medicine, The Scripps Research Institute, Scripps, Florida, Jupiter, Florida 33458
| | - Theodore M Kamenecka
- Department of Molecular Medicine, The Scripps Research Institute, Scripps, Florida, Jupiter, Florida 33458
| | - Jon Lindstrom
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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176
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Stokes C, Garai S, Kulkarni AR, Cantwell LN, Noviello CM, Hibbs RE, Horenstein NA, Abboud KA, Thakur GA, Papke RL. Heteromeric Neuronal Nicotinic Acetylcholine Receptors with Mutant β Subunits Acquire Sensitivity to α7-Selective Positive Allosteric Modulators. J Pharmacol Exp Ther 2019; 370:252-268. [PMID: 31175218 DOI: 10.1124/jpet.119.259499] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/04/2019] [Indexed: 01/29/2023] Open
Abstract
Homomeric α7 nicotinic acetylcholine receptors (nAChR) have an intrinsically low probability of opening that can be overcome by α7-selective positive allosteric modulators (PAMs), which bind at a site involving the second transmembrane domain (TM2). Mutation of a methionine that is unique to α7 at the 15' position of TM2 to leucine, the residue in most other nAChR subunits, largely eliminates the activity of such PAMs. We tested the effect of the reverse mutation (L15'M) in heteromeric nAChR receptors containing α4 and β2, which are the nAChR subunits that are most abundant in the brain. Receptors containing these mutations were found to be strongly potentiated by the α7 PAM 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS) but insensitive to the alternative PAM 1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-methylisoxazol-3-yl)-urea. The presence of the mutation in the β2 subunit was necessary and sufficient for TQS sensitivity. The primary effect of the mutation in the α4 subunit was to reduce responses to acetylcholine applied alone. Sensitivity to TQS required only a single mutant β subunit, regardless of the position of the mutant β subunit within the pentameric complex. Similar results were obtained when β2L15'M was coexpressed with α2 or α3 and when the L15'M mutation was placed in β4 and coexpressed with α2, α3, or α4. Functional receptors were not observed when β1L15'M subunits were coexpressed with other muscle nAChR subunits. The unique structure-activity relationship of PAMs and the α4β2L15'M receptor compared with α7 and the availability of high-resolution α4β2 structures may provide new insights into the fundamental mechanisms of nAChR allosteric potentiation. SIGNIFICANCE STATEMENT: Heteromeric neuronal nAChRs have a relatively high initial probability of channel activation compared to receptors that are homomers of α7 subunits but are insensitive to PAMs, which greatly increase the open probability of α7 receptors. These features of heteromeric nAChR can be reversed by mutation of a single residue present in all neuronal heteromeric nAChR subunits to the sequence found in α7. Specifically, the mutation of the TM2 15' leucine to methionine in α subunits reduces heteromeric receptor channel activation, while the same mutation in neuronal β subunits allows heteromeric receptors to respond to select α7 PAMs. The results indicate a key role for this residue in the functional differences in the two main classes of neuronal nAChRs.
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Affiliation(s)
- Clare Stokes
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Sumanta Garai
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Abhijit R Kulkarni
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Lucas N Cantwell
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Colleen M Noviello
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Ryan E Hibbs
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Khalil A Abboud
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Ganesh A Thakur
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
| | - Roger L Papke
- Departments of Pharmacology and Therapeutics (C.S., R.L.P.) and Chemistry (N.A.H., K.A.A.), University of Florida, Gainesville, Florida; Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., A.R.K., L.N.C., G.A.T.); and Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas (C.M.N., R.E.H.)
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177
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Yu R, Tae HS, Xu Q, Craik DJ, Adams DJ, Jiang T, Kaas Q. Molecular dynamics simulations of dihydro-β-erythroidine bound to the human α4β2 nicotinic acetylcholine receptor. Br J Pharmacol 2019; 176:2750-2763. [PMID: 31062355 DOI: 10.1111/bph.14698] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 03/20/2019] [Accepted: 04/10/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The heteromeric α4β2 nicotinic acetylcholine receptor (nAChR) is abundant in the human brain and is associated with a range of CNS disorders. This nAChR subtype has been recently crystallised in a conformation that was proposed to represent a desensitised state. Here, we investigated the conformational transition mechanism of this nAChR from a desensitised to a closed/resting state. EXPERIMENTAL APPROACH The competitive antagonist dihydro-β-erythroidine (DHβE) was modelled by replacement of the agonist nicotine in the α4β2 nAChR experimental structure. DHβE is used both in vitro and in vivo for its ability to block α4β2 nAChRs. This system was studied by three molecular dynamics simulations with a combined simulation time of 2.6 μs. Electrophysiological studies of mutated receptors were performed to validate the simulation results. KEY RESULTS The relative positions of the extracellular and transmembrane domains in the models are distinct from those of the desensitised state structure and are compatible with experimental structures of Cys-loop receptors captured in a closed/resting state. CONCLUSIONS AND IMPLICATIONS Our model suggests that the side chains of α4 L257 (9') and α4 L264 (16') are the main constrictions in the transmembrane pore. The involvement of position 9' in channel gating is well established, but position 16' was only previously identified as a gate for the bacterial channels, ELIC and GLIC. L257 but not L264 was found to influence the slow component of desensitisation. The structure of the antagonist-bound state proposed here should be valuable for the development of therapeutic or insecticide compounds.
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Affiliation(s)
- Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Han-Shen Tae
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Qingliang Xu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Tao Jiang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
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178
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Shivange AV, Borden PM, Muthusamy AK, Nichols AL, Bera K, Bao H, Bishara I, Jeon J, Mulcahy MJ, Cohen B, O'Riordan SL, Kim C, Dougherty DA, Chapman ER, Marvin JS, Looger LL, Lester HA. Determining the pharmacokinetics of nicotinic drugs in the endoplasmic reticulum using biosensors. J Gen Physiol 2019; 151:738-757. [PMID: 30718376 PMCID: PMC6571994 DOI: 10.1085/jgp.201812201] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/05/2018] [Accepted: 01/09/2019] [Indexed: 12/27/2022] Open
Abstract
Nicotine dependence is thought to arise in part because nicotine permeates into the endoplasmic reticulum (ER), where it binds to nicotinic receptors (nAChRs) and begins an "inside-out" pathway that leads to up-regulation of nAChRs on the plasma membrane. However, the dynamics of nicotine entry into the ER are unquantified. Here, we develop a family of genetically encoded fluorescent biosensors for nicotine, termed iNicSnFRs. The iNicSnFRs are fusions between two proteins: a circularly permutated GFP and a periplasmic choline-/betaine-binding protein engineered to bind nicotine. The biosensors iNicSnFR3a and iNicSnFR3b respond to nicotine by increasing fluorescence at [nicotine] <1 µM, the concentration in the plasma and cerebrospinal fluid of a smoker. We target iNicSnFR3 biosensors either to the plasma membrane or to the ER and measure nicotine kinetics in HeLa, SH-SY5Y, N2a, and HEK293 cell lines, as well as mouse hippocampal neurons and human stem cell-derived dopaminergic neurons. In all cell types, we find that nicotine equilibrates in the ER within 10 s (possibly within 1 s) of extracellular application and leaves as rapidly after removal from the extracellular solution. The [nicotine] in the ER is within twofold of the extracellular value. We use these data to run combined pharmacokinetic and pharmacodynamic simulations of human smoking. In the ER, the inside-out pathway begins when nicotine becomes a stabilizing pharmacological chaperone for some nAChR subtypes, even at concentrations as low as ∼10 nM. Such concentrations would persist during the 12 h of a typical smoker's day, continually activating the inside-out pathway by >75%. Reducing nicotine intake by 10-fold decreases activation to ∼20%. iNicSnFR3a and iNicSnFR3b also sense the smoking cessation drug varenicline, revealing that varenicline also permeates into the ER within seconds. Our iNicSnFRs enable optical subcellular pharmacokinetics for nicotine and varenicline during an early event in the inside-out pathway.
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Affiliation(s)
- Amol V Shivange
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Philip M Borden
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Anand K Muthusamy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Aaron L Nichols
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Kallol Bera
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Huan Bao
- Howard Hughes Medical Institute and Department of Neuroscience, University of Wisconsin, Madison, WI
| | - Ishak Bishara
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Janice Jeon
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Matthew J Mulcahy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Bruce Cohen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Saidhbhe L O'Riordan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Charlene Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Edwin R Chapman
- Howard Hughes Medical Institute and Department of Neuroscience, University of Wisconsin, Madison, WI
| | - Jonathan S Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
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179
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Structural basis for α-bungarotoxin insensitivity of neuronal nicotinic acetylcholine receptors. Neuropharmacology 2019; 160:107660. [PMID: 31163179 DOI: 10.1016/j.neuropharm.2019.05.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/25/2019] [Accepted: 05/30/2019] [Indexed: 01/22/2023]
Abstract
The ten types of nicotinic acetylcholine receptor α-subunits show substantial sequence homology, yet some types confer high affinity for α-bungarotoxin, whereas others confer negligible affinity. Combining sequence alignments with structural data reveals three residues unique to α-toxin-refractory α-subunits that coalesce within the 3D structure of the α4β2 receptor and are predicted to fit between loops I and II of α-bungarotoxin. Mutating any one of these residues, Lys189, Ile196 or Lys153, to the α-toxin-permissive counterpart fails to confer α-bungarotoxin binding. However, mutating both Lys189 and Ile196 affords α-bungarotoxin binding with an apparent dissociation constant of 104 nM, while combining mutation of Lys153 reduces the dissociation constant to 22 nM. Analogous residue substitutions also confer high affinity α-bungarotoxin binding upon α-toxin-refractory α2 and α3 subunits. α4β2 receptors engineered to bind α-bungarotoxin exhibit slow rates of α-toxin association and dissociation, and competition by cholinergic ligands typical of muscle nicotinic receptors. Receptors engineered to bind α-bungarotoxin co-sediment with muscle nicotinic receptors on sucrose gradients, and mirror single channel signatures of their α-toxin-refractory counterparts. Thus the inability of α-bungarotoxin to bind to neuronal nicotinic receptors arises from three unique and interdependent residues that coalesce within the receptor's 3D structure.
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180
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Scott S, Aricescu AR. A structural perspective on GABA A receptor pharmacology. Curr Opin Struct Biol 2019; 54:189-197. [PMID: 31129381 DOI: 10.1016/j.sbi.2019.03.023] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 10/26/2022]
Abstract
GABAA receptors are pentameric ligand-gated chloride channels of crucial importance for the vertebrate nervous system physiology. They typically modulate the fast inhibitory neurotransmission, and represent the target receptors for major classes of drugs used in the clinic, such as benzodiazepines and general anesthetics. Recent technological progress in structural biology, in particular single-particle cryo-electron microscopy, has led to fundamental advances in understanding the detailed organization and signalling mechanisms of major GABAA receptor subtypes. This effort culminated with the high-resolution structural analysis of an intact, full-length human heteropentameric receptor, α1β3γ2, in a lipid bilayer and in complex with small molecule ligands including the commonly used benzodiazepines diazepam (Valium) and alprazolam (Xanax). These structures reveal multiple aspects of receptor activation and provide a path for rational design of subunit-specific GABAA receptor modulators.
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Affiliation(s)
- Suzanne Scott
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.
| | - Alexandru Radu Aricescu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
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181
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Zouridakis M, Papakyriakou A, Ivanov IA, Kasheverov IE, Tsetlin V, Tzartos S, Giastas P. Crystal Structure of the Monomeric Extracellular Domain of α9 Nicotinic Receptor Subunit in Complex With α-Conotoxin RgIA: Molecular Dynamics Insights Into RgIA Binding to α9α10 Nicotinic Receptors. Front Pharmacol 2019; 10:474. [PMID: 31118896 PMCID: PMC6504684 DOI: 10.3389/fphar.2019.00474] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/15/2019] [Indexed: 12/20/2022] Open
Abstract
The α9 subunit of nicotinic acetylcholine receptors (nAChRs) exists mainly in heteropentameric assemblies with α10. Accumulating data indicate the presence of three different binding sites in α9α10 nAChRs: the α9(+)/α9(−), the α9(+)/α10(−), and the α10(+)/α9(−). The major role of the principal (+) side of the extracellular domain (ECD) of α9 subunit in binding of the antagonists methyllylcaconitine and α-bungarotoxin was shown previously by the crystal structures of the monomeric α9-ECD with these molecules. Here we present the 2.26-Å resolution crystal structure of α9-ECD in complex with α-conotoxin (α-Ctx) RgIA, a potential drug for chronic pain, the first structure reported for a complex between an nAChR domain and an α-Ctx. Superposition of this structure with those of other α-Ctxs bound to the homologous pentameric acetylcholine binding proteins revealed significant similarities in the orientation of bound conotoxins, despite the monomeric state of the α9-ECD. In addition, ligand-binding studies calculated a binding affinity of RgIA to the α9-ECD at the low micromolar range. Given the high identity between α9 and α10 ECDs, particularly at their (+) sides, the presented structure was used as template for molecular dynamics simulations of the ECDs of the human α9α10 nAChR in pentameric assemblies. Our results support a favorable binding of RgIA at α9(+)/α9(−) or α10(+)/α9(−) rather than the α9(+)/α10(−) interface, in accordance with previous mutational and functional data.
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Affiliation(s)
- Marios Zouridakis
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | | | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Victor Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,PhysBio of MEPhI, Moscow, Russia
| | - Socrates Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.,Department of Pharmacy, University of Patras, Patras, Greece
| | - Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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182
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Changeux JP. The nicotinic acetylcholine receptor: a typical 'allosteric machine'. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0174. [PMID: 29735728 DOI: 10.1098/rstb.2017.0174] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2017] [Indexed: 12/26/2022] Open
Abstract
The concept of allosteric interaction was initially proposed to account for the inhibitory feedback mechanism mediated by bacterial regulatory enzymes. In contrast with the classical mechanism of competitive, steric, interaction between ligands for a common site, allosteric interactions take place between topographically distinct sites and are mediated by a discrete and reversible conformational change of the protein. The concept was soon extended to membrane receptors for neurotransmitters and shown to apply to the signal transduction process which, in the case of the acetylcholine nicotinic receptor (nAChR), links the ACh binding site to the ion channel. Pharmacological effectors, referred to as allosteric modulators, such as Ca2+ ions and ivermectin, were discovered that enhance the transduction process when they bind to sites distinct from the orthosteric ACh site and the ion channel. The recent X-ray and electron microscopy structures, at atomic resolution, of the resting and active conformations of several homologues of the nAChR, in combination with atomistic molecular dynamics simulations reveal a stepwise quaternary transition in the transduction process with tertiary changes modifying the boundaries between subunits. These interfaces host orthosteric and allosteric modulatory sites which structural organization changes in the course of the transition. The nAChR appears as a typical allosteric machine. The model emerging from these studies has led to the conception and development of several new pharmacological agents.This article is part of a discussion meeting issue 'Allostery and molecular machines'.
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Affiliation(s)
- Jean-Pierre Changeux
- CNRS UMR 3571, Institut Pasteur, Paris 75724, France .,Communications Cellulaires, Collège de France, Paris 75005, France
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183
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Tripathy S, Zheng W, Auerbach A. A single molecular distance predicts agonist binding energy in nicotinic receptors. J Gen Physiol 2019; 151:452-464. [PMID: 30635370 PMCID: PMC6445573 DOI: 10.1085/jgp.201812212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/07/2018] [Accepted: 12/11/2018] [Indexed: 11/20/2022] Open
Abstract
Agonists turn on receptors because they bind more strongly to active (R*) versus resting (R) conformations of their target sites. Here, to explore how agonists activate neuromuscular acetylcholine receptors, we built homology models of R and R* neurotransmitter binding sites, docked ligands to those sites, ran molecular dynamics simulations to relax ("equilibrate") the structures, measured binding site structural parameters, and correlated them with experimental agonist binding energies. Each binding pocket is a pyramid formed by five aromatic amino acids and covered partially by loop C. We found that in R* versus R, loop C is displaced outward, the pocket is smaller and skewed, the agonist orientation is reversed, and a key nitrogen atom in the agonist is closer to the pocket center (distance dx) and a tryptophan pair but farther from αY190. Of these differences, the change in dx shows the largest correlation with experimental binding energy and provides a good estimate of agonist affinity, efficacy, and efficiency. Indeed, concentration-response curves can be calculated from just dx values. The contraction and twist of the binding pocket upon activation resemble gating rearrangements of the extracellular domain of related receptors at a smaller scale.
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Affiliation(s)
- Sushree Tripathy
- Department of Physics, State University of New York, Buffalo, Buffalo, NY
| | - Wenjun Zheng
- Department of Physics, State University of New York, Buffalo, Buffalo, NY
| | - Anthony Auerbach
- Department of Physiology and Biophysics, State University of New York, Buffalo, Buffalo, NY
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184
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Yu Z, Chiara DC, Savechenkov PY, Bruzik KS, Cohen JB. A photoreactive analog of allopregnanolone enables identification of steroid-binding sites in a nicotinic acetylcholine receptor. J Biol Chem 2019; 294:7892-7903. [PMID: 30923128 DOI: 10.1074/jbc.ra118.007172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/27/2019] [Indexed: 11/06/2022] Open
Abstract
Many neuroactive steroids potently and allosterically modulate pentameric ligand-gated ion channels, including GABAA receptors (GABAAR) and nicotinic acetylcholine receptors (nAChRs). Allopregnanolone and its synthetic analog alphaxalone are GABAAR-positive allosteric modulators (PAMs), whereas alphaxalone and most neuroactive steroids are nAChR inhibitors. In this report, we used 11β-(p-azidotetrafluorobenzoyloxy)allopregnanolone (F4N3Bzoxy-AP), a general anesthetic and photoreactive allopregnanolone analog that is a potent GABAAR PAM, to characterize steroid-binding sites in the Torpedo α2βγδ nAChR in its native membrane environment. We found that F4N3Bzoxy-AP (IC50 = 31 μm) is 7-fold more potent than alphaxalone in inhibiting binding of the channel blocker [3H]tenocyclidine to nAChRs in the desensitized state. At 300 μm, neither steroid inhibited binding of [3H]tetracaine, a closed-state selective channel blocker, or of [3H]acetylcholine. Photolabeling identified three distinct [3H]F4N3Bzoxy-AP-binding sites in the nAChR transmembrane domain: 1) in the ion channel, identified by photolabeling in the M2 helices of βVal-261 and δVal-269 (position M2-13'); 2) at the interface between the αM1 and αM4 helices, identified by photolabeling in αM1 (αCys-222/αLeu-223); and 3) at the lipid-protein interface involving γTrp-453 (M4), a residue photolabeled by small lipophilic probes and promegestone, a steroid nAChR antagonist. Photolabeling in the ion channel and αM1 was higher in the nAChR-desensitized state than in the resting state and inhibitable by promegestone. These results directly indicate a steroid-binding site in the nAChR ion channel and identify additional steroid-binding sites also occupied by other lipophilic nAChR antagonists.
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Affiliation(s)
- Zhiyi Yu
- From the Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - David C Chiara
- From the Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Pavel Y Savechenkov
- the Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Karol S Bruzik
- the Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Jonathan B Cohen
- From the Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115 and
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185
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Mazzaferro S, Bermudez I, Sine SM. Potentiation of a neuronal nicotinic receptor via pseudo-agonist site. Cell Mol Life Sci 2019; 76:1151-1167. [PMID: 30600358 PMCID: PMC8022356 DOI: 10.1007/s00018-018-2993-7] [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: 07/09/2018] [Revised: 11/28/2018] [Accepted: 12/10/2018] [Indexed: 11/26/2022]
Abstract
Neuronal nicotinic receptors containing α4 and β2 subunits assemble in two pentameric stoichiometries, (α4)3(β2)2 and (α4)2(β2)3, each with distinct pharmacological signatures; (α4)3(β2)2 receptors are strongly potentiated by the drug NS9283, whereas (α4)2(β2)3 receptors are unaffected. Despite this stoichiometry-selective pharmacology, the molecular identity of the target for NS9283 remains elusive. Here, studying (α4)3(β2)2 receptors, we show that mutations at either the principal face of the β2 subunit or the complementary face of the α4 subunit prevent NS9283 potentiation of ACh-elicited single-channel currents, suggesting the drug targets the β2-α4 pseudo-agonist sites, the α4-α4 agonist site, or both sites. To distinguish among these possibilities, we generated concatemeric receptors with mutations at specified subunit interfaces, and monitored the ability of NS9283 to potentiate ACh-elicited single-channel currents. We find that a mutation at the principal face of the β2 subunit at either β2-α4 pseudo-agonist site suppresses potentiation, whereas mutation at the complementary face of the α4 subunit at the α4-α4 agonist site allows a significant potentiation. Thus, monitoring potentiation of single concatemeric receptor channels reveals that the β2-α4 pseudo-agonist sites are required for stoichiometry-selective drug action. Together with the recently determined structure of the (α4)3(β2)2 receptor, the findings have implications for structure-guided drug design.
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Affiliation(s)
- Simone Mazzaferro
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Isabel Bermudez
- School of Life Sciences, Oxford Brookes University, Oxford, OX3 OBP, UK
| | - Steven M Sine
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA.
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA.
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186
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Ren J, Zhu X, Xu P, Li R, Fu Y, Dong S, Zhangsun D, Wu Y, Luo S. d-Amino Acid Substitution of α-Conotoxin RgIA Identifies its Critical Residues and Improves the Enzymatic Stability. Mar Drugs 2019; 17:md17030142. [PMID: 30823399 PMCID: PMC6472032 DOI: 10.3390/md17030142] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/17/2019] [Accepted: 02/22/2019] [Indexed: 12/22/2022] Open
Abstract
α-Conotoxin RgIA is a selective and potent competitive antagonist of rat α9α10 nicotinic acetylcholine receptors (nAChR), but it is much less potent towards human α9α10 nAChR. Furthermore, RgIA is susceptible to proteolytic degradation due to containing four arginine residues. These disadvantages greatly limit its use for clinical applications. The purpose of this research was to identify critical stereocenters of RgIA and discover more stable analogues, enhancing its bioavailability by using the d-amino acid scan method. The activity of each variant was investigated against rat and human α9α10 nAChRs, which were expressed in Xenopus oocytes. Experimental assays showed that 14 out of 15 analogues had a substantial reduction in potency towards rat α9α10 nAChR. Noticeably, analogue 13 retained full biological activity compared with RgIA. Meanwhile, two other analogues, 14 and 15, of which l-Args were substituted with d-Args, exhibited a significantly increased potency towards human α9α10 nAChR, although these analogues showed decreased activities against rat α9α10 nAChR. Additionally, these three analogues exhibited a high resistance against enzymatic degradation in human serum and simulated intestinal fluid (SIF). Collectively, our findings suggest that a d-amino acid scan is a useful strategy for investigating how the side-chain chirality of amino acids affects the structure and function of peptides and may facilitate the development of more stable analogues to increase therapeutic potential.
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Affiliation(s)
- Jie Ren
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Xiaopeng Zhu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Pan Xu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Rui Li
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Ying Fu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Shuai Dong
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
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187
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Kulbatskii DS, Bychkov ML, Lyukmanova EN. Human Nicotinic Acetylcholine Receptors: Part I—Structure, Function, and Role in Neuromuscular Transmission and CNS Functioning. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162018060043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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188
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Bennett JA, Ture SK, Schmidt RA, Mastrangelo MA, Cameron SJ, Terry LE, Yule DI, Morrell CN, Lowenstein CJ. Acetylcholine Inhibits Platelet Activation. J Pharmacol Exp Ther 2019; 369:182-187. [PMID: 30765424 DOI: 10.1124/jpet.118.253583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 02/12/2019] [Indexed: 12/18/2022] Open
Abstract
Platelets are key mediators of thrombosis. Many agonists of platelet activation are known, but fewer endogenous inhibitors of platelets, such as prostacyclin and nitric oxide (NO), have been identified. Acetylcholinesterase inhibitors, such as donepezil, can cause bleeding in patients, but the underlying mechanisms are not well understood. We hypothesized that acetylcholine is an endogenous inhibitor of platelets. We measured the effect of acetylcholine or analogs of acetylcholine on human platelet activation ex vivo. Acetylcholine and analogs of acetylcholine inhibited platelet activation, as measured by P-selectin translocation and glycoprotein IIb IIIa conformational changes. Conversely, we found that antagonists of the acetylcholine receptor, such as pancuronium, enhance platelet activation. Furthermore, drugs inhibiting acetylcholinesterase, such as donepezil, also inhibit platelet activation, suggesting that platelets release acetylcholine. We found that NO mediates acetylcholine inhibition of platelets. Our data suggest that acetylcholine is an endogenous inhibitor of platelet activation. The cholinergic system may be a novel target for antithrombotic therapies.
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Affiliation(s)
- John A Bennett
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Sara K Ture
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Rachel A Schmidt
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Michael A Mastrangelo
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Scott J Cameron
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Lara E Terry
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - David I Yule
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Craig N Morrell
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Charles J Lowenstein
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
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189
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Matera C, Bono F, Pelucchi S, Collo G, Bontempi L, Gotti C, Zoli M, De Amici M, Missale C, Fiorentini C, Dallanoce C. The novel hybrid agonist HyNDA-1 targets the D3R-nAChR heteromeric complex in dopaminergic neurons. Biochem Pharmacol 2019; 163:154-168. [PMID: 30772268 DOI: 10.1016/j.bcp.2019.02.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/13/2019] [Indexed: 02/07/2023]
Abstract
In this paper, we designed, synthesized and tested a small set of three new derivatives potentially targeting the D3R-nAChR heteromer, a receptor complex recently identified and characterized as the molecular entity that, in dopaminergic neurons, mediates the neurotrophic effects of nicotine. By means of a partially rigidified spacer of variable length, we incorporated in the new compounds (1a-c) the pharmacophoric substructure of a known β2-subunit-containing nAChR agonist (A-84543) and that of the D2/D3R agonist drug ropinirole. All the compounds retained the ability to bind with high affinity both β2-subunit-containing nAChR and D3R. Compound 1a, renamed HyNDA-1, which is characterized by the shortest linker moiety, was the most interesting ligand. We found, in fact, that HyNDA-1 significantly modulated structural plasticity on both mice and human dopaminergic neurons, an effect strongly prevented by co-incubating this ligand with either nAChR or D3R antagonists. Moreover, the neurotrophic effects of HyNDA-1 were specifically lost by disrupting the complex with specific interfering peptides. Interestingly, by using the Bioluminescence Resonance Energy Transfer 2 (BRET2) assay in HEK-293 transfected cells, we also found that HyNDA-1 has the ability to increase the affinity of interaction between nAChR and D3R. Overall, our results indicate that the neurotrophic effects of HyNDA-1 are mediated by activation of the D3R-nAChR heteromeric complex specifically expressed on dopaminergic neurons.
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Affiliation(s)
- Carlo Matera
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Farmaceutica "Pietro Pratesi", Università degli Studi di Milano, Via L. Mangiagalli 25, 20133 Milano, Italy
| | - Federica Bono
- Dipartimento di Medicina Molecolare e Traslazionale - Sezione di Farmacologia, Università degli Studi di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Silvia Pelucchi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milano, Italy
| | - Ginetta Collo
- Dipartimento di Medicina Molecolare e Traslazionale - Sezione di Farmacologia, Università degli Studi di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Leonardo Bontempi
- Dipartimento di Medicina Molecolare e Traslazionale - Sezione di Farmacologia, Università degli Studi di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Cecilia Gotti
- Istituto di Neuroscienze, CNR, Via Vanvitelli 32, 20129 Milan, Italy
| | - Michele Zoli
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
| | - Marco De Amici
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Farmaceutica "Pietro Pratesi", Università degli Studi di Milano, Via L. Mangiagalli 25, 20133 Milano, Italy
| | - Cristina Missale
- Dipartimento di Medicina Molecolare e Traslazionale - Sezione di Farmacologia, Università degli Studi di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Chiara Fiorentini
- Dipartimento di Medicina Molecolare e Traslazionale - Sezione di Farmacologia, Università degli Studi di Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Clelia Dallanoce
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Farmaceutica "Pietro Pratesi", Università degli Studi di Milano, Via L. Mangiagalli 25, 20133 Milano, Italy.
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190
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Turner MW, Marquart LA, Phillips PD, McDougal OM. Mutagenesis of α-Conotoxins for Enhancing Activity and Selectivity for Nicotinic Acetylcholine Receptors. Toxins (Basel) 2019; 11:E113. [PMID: 30781866 PMCID: PMC6409848 DOI: 10.3390/toxins11020113] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 02/04/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are found throughout the mammalian body and have been studied extensively because of their implication in a myriad of diseases. α-Conotoxins (α-CTxs) are peptide neurotoxins found in the venom of marine snails of genus Conus. α-CTxs are potent and selective antagonists for a variety of nAChR isoforms. Over the past 40 years, α-CTxs have proven to be valuable molecular probes capable of differentiating between closely related nAChR subtypes and have contributed greatly to understanding the physiological role of nAChRs in the mammalian nervous system. Here, we review the amino acid composition and structure of several α-CTxs that selectively target nAChR isoforms and explore strategies and outcomes for introducing mutations in native α-CTxs to direct selectivity and enhance binding affinity for specific nAChRs. This review will focus on structure-activity relationship studies involving native α-CTxs that have been rationally mutated and molecular interactions that underlie binding between ligand and nAChR isoform.
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Affiliation(s)
- Matthew W Turner
- Biomolecular Sciences Graduate Programs, Boise State University; Boise, ID 83725, USA.
| | - Leanna A Marquart
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
| | - Paul D Phillips
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
| | - Owen M McDougal
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
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191
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Villa C, Colombo G, Meneghini S, Gotti C, Moretti M, Ferini-Strambi L, Chisci E, Giovannoni R, Becchetti A, Combi R. CHRNA2 and Nocturnal Frontal Lobe Epilepsy: Identification and Characterization of a Novel Loss of Function Mutation. Front Mol Neurosci 2019; 12:17. [PMID: 30809122 PMCID: PMC6379349 DOI: 10.3389/fnmol.2019.00017] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/17/2019] [Indexed: 12/21/2022] Open
Abstract
Mutations in genes coding for subunits of the neuronal nicotinic acetylcholine receptor (nAChR) have been involved in familial sleep-related hypermotor epilepsy (also named autosomal dominant nocturnal frontal lobe epilepsy, ADNFLE). Most of these mutations reside in CHRNA4 and CHRNB2 genes, coding for the α4 and β2 nAChR subunits, respectively. Two mutations with contrasting functional effects were also identified in the CHRNA2 gene coding for the α2 subunit. Here, we report the third mutation in the CHRNA2, found in a patient showing ADNFLE. The patient was examined by scalp EEG, contrast-enhanced brain magnetic resonance imaging (MRI), and nocturnal video-polysomnographic recording. All exons and the exon-intron boundaries of CHRNA2, CHRNA4, CHRNB2, CRH, KCNT1 were amplified and Sanger sequenced. In the proband, we found a c.754T>C (p.Tyr252His) missense mutation located in the N-terminal ligand-binding domain and inherited from the mother. Functional studies were performed by transient co-expression of α2 and α2Tyr252His, with either β2 or β4, in human embryonic kidney (HEK293) cells. Equimolar amounts of subunits expression were obtained by using F2A-based multi-cistronic constructs encoding for the genes relative to the nAChR subunits of interest and for the enhanced green fluorescent protein. The mutation reduced the maximal currents by approximately 80% in response to saturating concentrations of nicotine in homo- and heterozygous form, in both the α2β4 and α2β2 nAChR subtypes. The effect was accompanied by a strong right-shift of the concentration-response to nicotine. Similar effects were observed using ACh. Negligible effects were produced by α2Tyr252His on the current reversal potential. Moreover, binding of (±)-[3H]Epibatidine revealed an approximately 10-fold decrease of both Kd and Bmax (bound ligand in saturating conditions), in cells expressing α2Tyr252His. The reduced Bmax and whole-cell currents were not caused by a decrease in mutant receptor expression, as minor effects were produced by α2Tyr252His on the level of transcripts and the membrane expression of α2β4 nAChR. Overall, these results suggest that α2Tyr252His strongly reduced the number of channels bound to the agonist, without significantly altering the overall channel expression. We conclude that mutations in CHRNA2 are more commonly linked to ADNFLE than previously thought, and may cause a loss-of-function phenotype.
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Affiliation(s)
- Chiara Villa
- School of Medicine and Surgery, University of Milano - Bicocca, Monza, Italy
| | - Giulia Colombo
- Department of Biotechnology and Biosciences, University of Milano - Bicocca, Milan, Italy
| | - Simone Meneghini
- Department of Biotechnology and Biosciences, University of Milano - Bicocca, Milan, Italy
| | | | - Milena Moretti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Luigi Ferini-Strambi
- Department of Clinical Neurosciences, San Raffaele Scientific Institute, Sleep Disorders Center, Vita-Salute San Raffaele University, Milan, Italy
| | - Elisa Chisci
- School of Medicine and Surgery, University of Milano - Bicocca, Monza, Italy
| | - Roberto Giovannoni
- School of Medicine and Surgery, University of Milano - Bicocca, Monza, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano - Bicocca, Milan, Italy
| | - Romina Combi
- School of Medicine and Surgery, University of Milano - Bicocca, Monza, Italy
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192
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Manetti D, Garifulina A, Bartolucci G, Bazzicalupi C, Bellucci C, Chiaramonte N, Dei S, Di Cesare Mannelli L, Ghelardini C, Gratteri P, Spirova E, Shelukhina I, Teodori E, Varani K, Tsetlin V, Romanelli MN. New Rigid Nicotine Analogues, Carrying a Norbornane Moiety, Are Potent Agonists of α7 and α3* Nicotinic Receptors. J Med Chem 2019; 62:1887-1901. [PMID: 30681854 DOI: 10.1021/acs.jmedchem.8b01372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A three-dimensional database search has been applied to design a series of endo- and exo-3-(pyridin-3-yl)bicyclo[2.2.1]heptan-2-amines as nicotinic receptor ligands. The synthesized compounds were tested in radioligand binding assay on rat cortex against [3H]-cytisine and [3H]-methyllycaconitine to measure their affinity for α4β2* and α7* nicotinic receptors. The new derivatives showed some preference for the α4β2* over the α7* subtype, with their affinity being dependent on the endo/exo isomerism and on the methylation degree of the basic nitrogen. The endo primary amines displayed the lowest Ki values on both receptor subtypes. Selected compounds (1a, 2a, 3a, and 6a) were tested on heterologously expressed α4β2, α7, and α3β2 receptors and on SHSY-5Y cells. Compounds 1a and 2a showed α4β2 antagonistic properties while behaved as full agonists on recombinant α7 and on SHSY5Y cells. On the α3β2 subtype, only the chloro derivative 2a showed full agonist activity and submicromolar potency (EC50 = 0.43 μM). The primary amines described here represent new chemotypes for the α7 and α3* receptor subtypes.
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Affiliation(s)
- Dina Manetti
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Alexandra Garifulina
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Gianluca Bartolucci
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Carla Bazzicalupi
- Department of Chemistry "Ugo Schiff" , University of Florence , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy
| | - Cristina Bellucci
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Niccolò Chiaramonte
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Silvia Dei
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Lorenzo Di Cesare Mannelli
- Department of NEUROFARBA, Section of Pharmacology and Toxicology , University of Florence , Viale G Pieraccini 6 , 50139 Firenze , Italy
| | - Carla Ghelardini
- Department of NEUROFARBA, Section of Pharmacology and Toxicology , University of Florence , Viale G Pieraccini 6 , 50139 Firenze , Italy
| | - Paola Gratteri
- Department of NEUROFARBA, Laboratory of Molecular Modeling Cheminformatics & QSAR , University of Firenze , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Ekaterina Spirova
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Irina Shelukhina
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Elisabetta Teodori
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Katia Varani
- Institute of Pharmacology , University of Ferrara , Via Fossato di Mortara 17-19 , 44100 Ferrara , Italy
| | - Victor Tsetlin
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Maria Novella Romanelli
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
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193
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Abstract
The pentameric γ-aminobutyric acid type A receptors are ion channels activated by ligands, which intervene in the rapid inhibitory transmission in the mammalian CNS. Due to their rich pharmacology and therapeutic potential, it is essential to understand their structure and function thoroughly. This deep characterization was hampered by the lack of experimental structural information for many years. Thus, computational techniques have been extensively combined with experimental data, in order to undertake the study of γ-aminobutyric acid type A receptors and their interaction with drugs. Here, we review the exciting journey made to assess the structures of these receptors and outline major outcomes. Finally, we discuss the brand new structure of the α1β2γ2 subtype and the amazing advances it brings to the field.
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194
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Nayak TK, Vij R, Bruhova I, Shandilya J, Auerbach A. Efficiency measures the conversion of agonist binding energy into receptor conformational change. J Gen Physiol 2019; 151:465-477. [PMID: 30635369 PMCID: PMC6445574 DOI: 10.1085/jgp.201812215] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022] Open
Abstract
Receptors alternate between resting↔active conformations that bind agonists with low↔high affinity. Here, we define a new agonist attribute, energy efficiency (η), as the fraction of ligand-binding energy converted into the mechanical work of the activation conformational change. η depends only on the resting/active agonist-binding energy ratio. In a plot of activation energy versus binding energy (an "efficiency" plot), the slope gives η and the y intercept gives the receptor's intrinsic activation energy (without agonists; ΔG0). We used single-channel electrophysiology to estimate η for eight different agonists and ΔG0 in human endplate acetylcholine receptors (AChRs). From published equilibrium constants, we also estimated η for agonists of KCa1.1 (BK channels) and muscarinic, γ-aminobutyric acid, glutamate, glycine, and aryl-hydrocarbon receptors, and ΔG0 for all of these except KCa1.1. Regarding AChRs, η is 48-56% for agonists related structurally to acetylcholine but is only ∼39% for agonists related to epibatidine; ΔG0 is 8.4 kcal/mol in adult and 9.6 kcal/mol in fetal receptors. Efficiency plots for all of the above receptors are approximately linear, with η values between 12% and 57% and ΔG0 values between 2 and 12 kcal/mol. Efficiency appears to be a general attribute of agonist action at receptor binding sites that is useful for understanding binding mechanisms, categorizing agonists, and estimating concentration-response relationships.
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Affiliation(s)
- Tapan K Nayak
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Ridhima Vij
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Iva Bruhova
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Jayasha Shandilya
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Anthony Auerbach
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
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195
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Spirova EN, Ivanov IA, Kasheverov IE, Kudryavtsev DS, Shelukhina IV, Garifulina AI, Son LV, Lummis SCR, Malca-Garcia GR, Bussmann RW, Hennig L, Giannis A, Tsetlin VI. Curare alkaloids from Matis Dart Poison: Comparison with d-tubocurarine in interactions with nicotinic, 5-HT3 serotonin and GABAA receptors. PLoS One 2019; 14:e0210182. [PMID: 30608952 PMCID: PMC6319706 DOI: 10.1371/journal.pone.0210182] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/18/2018] [Indexed: 12/16/2022] Open
Abstract
Several novel bisbenzylisoquinoline alkaloids (BBIQAs) have recently been isolated from a Matis tribe arrow poison and shown by two-electrode voltage-clamp to inhibit mouse muscle nicotinic acetylcholine receptors (nAChR). Here, using radioligand assay with Aplysia californica AChBP and radioiodinated α-bungarotoxin ([125I]-αBgt), we show that BBIQA1, BBIQA2, and d-tubocurarine (d-TC) have similar affinities to nAChR orthosteric site. However, a competition with [125I]-αBgt for binding to the Torpedo californica muscle-type nAChR revealed that BBIQAs1, 2, and 3 are less potent (IC50s = 26.3, 8.75, and 17.0 μM) than d-TC (IC50 = 0.39 μM), while with α7 nAChR in GH4C1 cells, BBIQA1 was less potent that d-TC (IC50s = 162 μM and 7.77 μM, respectively), but BBIQA2 was similar (IC50 = 5.52 μM). In inhibiting the Ca2+ responses induced by acetylcholine in Neuro2a cells expressing the mouse adult α1β1εδ nAChR or human α7 nAChR, BBIQAs1 and 2 had similar potencies to d-TC (IC50s in the range 0.75-3.08 μM). Our data suggest that BBIQA1 and BBIQA2 can inhibit adult muscle α1β1εδ nAChR by both competitive and noncompetitive mechanisms. Further experiments on neuronal α3β2, α4β2, and α9α10 nAChRs, expressed in Xenopus laevis oocytes, showed that similar potencies for BBIQAs1, 2, and d-TC. With α3β2γ2 GABAAR currents were almost completely inhibited by d-TC at a high (100 μM) concentration, but BBIQAs1 and 2 were less potent (only 40-50% inhibition), whereas in competition with Alexa Fluor 546-α-cobratoxin for binding to α1β3γ2 GABAAR in Neuro2a cells, d-TC and these analogs had comparable affinities. Especially interesting effects of BBIQAs1 and 2 in comparison with d-TC were observed for 5-HT3AR: BBIQA1 and BBIQA2 were 5- and 87-fold less potent than d-TC (IC50 = 22.63 nM). Thus, our results reveal that these BBIQAs differ from d-TC in their potencies towards certain Cys-loop receptors, and we suggest that understanding the reasons behind this might be useful for future drug design.
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Affiliation(s)
- Ekaterina N. Spirova
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Igor A. Ivanov
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Igor E. Kasheverov
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, Russia
| | - Denis S. Kudryavtsev
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Irina V. Shelukhina
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexandra I. Garifulina
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Lina V. Son
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Sarah C. R. Lummis
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Gonzalo R. Malca-Garcia
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, United States of America
| | | | - Lothar Hennig
- Institut für Organische Chemie, Fakultät für Chemie und Mineralogie, Universität Leipzig, Leipzig, Germany
| | - Athanassios Giannis
- Institut für Organische Chemie, Fakultät für Chemie und Mineralogie, Universität Leipzig, Leipzig, Germany
| | - Victor I. Tsetlin
- Department of Molecular Neuroimmune signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- PhysBio of MEPhI, Moscow, Russia
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196
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Przybył AK, Maj E, Wietrzyk J, Kubicki M. Spectroscopic, structural and anticancer activity studies of (−)-cytisine halogenated N-benzyl derivatives. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.09.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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197
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Quadri M, Garai S, Thakur GA, Stokes C, Gulsevin A, Horenstein NA, Papke RL. Macroscopic and Microscopic Activation of α7 Nicotinic Acetylcholine Receptors by the Structurally Unrelated Allosteric Agonist-Positive Allosteric Modulators (ago-PAMs) B-973B and GAT107. Mol Pharmacol 2019; 95:43-61. [PMID: 30348894 PMCID: PMC6277926 DOI: 10.1124/mol.118.113340] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/18/2018] [Indexed: 01/25/2023] Open
Abstract
B-973 is an efficacious type II positive allosteric modulator (PAM) of α7 nicotinic acetylcholine receptors that, like 4BP-TQS and its active isomer GAT107, can produce direct allosteric activation in addition to potentiation of orthosteric agonist activity, which identifies it as an allosteric activating (ago)-PAM. We compared the properties of B-973B, the active enantiomer of B-973, with those of GAT107 regarding the separation of allosteric potentiation and activation. Both ago-PAMs can strongly activate mutants of α7 that are insensitive to standard orthosteric agonists like acetylcholine. Likewise, the activity of both ago-PAMs is largely eliminated by the M254L mutation in the putative transmembrane PAM-binding site. Allosteric activation by B-973B appeared more protracted than that produced by GAT107, and B-973B responses were relatively insensitive to the noncompetitive antagonist mecamylamine compared with GAT107 responses. Similar differences are also seen in the single-channel currents. The two agents generate unique profiles of full-conductance and subconductance states, with B-973B producing protracted bursts, even in the presence of mecamylamine. Modeling and docking studies suggest that the molecular basis for these effects depends on specific interactions in both the extracellular and transmembrane domains of the receptor.
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Affiliation(s)
- Marta Quadri
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Sumanta Garai
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Ganesh A Thakur
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Clare Stokes
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Alican Gulsevin
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
| | - Roger L Papke
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., A.G., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (S.G., G.A.T.)
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198
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Structural biology and structure–function relationships of membrane proteins. Biochem Soc Trans 2018; 47:47-61. [DOI: 10.1042/bst20180269] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/22/2018] [Accepted: 10/29/2018] [Indexed: 01/02/2023]
Abstract
Abstract
The study of structure–function relationships of membrane proteins (MPs) has been one of the major goals in the field of structural biology. Many Noble Prizes regarding remarkable accomplishments in MP structure determination and biochemistry have been awarded over the last few decades. Mutations or improper folding of these proteins are associated with numerous serious illnesses. Therefore, as important drug targets, the study of their primary sequence and three-dimensional fold, combined with cell-based assays, provides vital information about their structure–function relationships. Today, this information is vital to drug discovery and medicine. In the last two decades, many have been the technical advances and breakthroughs in the field of MP structural biology that have contributed to an exponential growth in the number of unique MP structures in the Protein Data Bank. Nevertheless, given the medical importance and many unanswered questions, it will never be an excess of MP structures, regardless of the method used. Owing to the extension of the field, in this brief review, we will only focus on structure–function relationships of the three most significant pharmaceutical classes: G protein-coupled receptors, ion channels and transporters.
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199
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Electrostatics, proton sensor, and networks governing the gating transition in GLIC, a proton-gated pentameric ion channel. Proc Natl Acad Sci U S A 2018; 115:E12172-E12181. [PMID: 30541892 DOI: 10.1073/pnas.1813378116] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The pentameric ligand-gated ion channel (pLGIC) from Gloeobacter violaceus (GLIC) has provided insightful structure-function views on the permeation process and the allosteric regulation of the pLGICs family. However, GLIC is activated by pH instead of a neurotransmitter and a clear picture for the gating transition driven by protons is still lacking. We used an electrostatics-based (finite difference Poisson-Boltzmann/Debye-Hückel) method to predict the acidities of all aspartic and glutamic residues in GLIC, both in its active and closed-channel states. Those residues with a predicted pKa close to the experimental pH50 were individually replaced by alanine and the resulting variant receptors were titrated by ATR/FTIR spectroscopy. E35, located in front of loop F far away from the orthosteric site, appears as the key proton sensor with a measured individual pKa at 5.8. In the GLIC open conformation, E35 is connected through a water-mediated hydrogen-bond network first to the highly conserved electrostatic triad R192-D122-D32 and then to Y197-Y119-K248, both located at the extracellular domain-transmembrane domain interface. The second triad controls a cluster of hydrophobic side chains from the M2-M3 loop that is remodeled during the gating transition. We solved 12 crystal structures of GLIC mutants, 6 of them being trapped in an agonist-bound but nonconductive conformation. Combined with previous data, this reveals two branches of a continuous network originating from E35 that reach, independently, the middle transmembrane region of two adjacent subunits. We conclude that GLIC's gating proceeds by making use of loop F, already known as an allosteric site in other pLGICs, instead of the classic orthosteric site.
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200
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Jones AK. Genomics, cys-loop ligand-gated ion channels and new targets for the control of insect pests and vectors. CURRENT OPINION IN INSECT SCIENCE 2018; 30:1-7. [PMID: 30553480 DOI: 10.1016/j.cois.2018.07.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 07/29/2018] [Accepted: 07/29/2018] [Indexed: 05/27/2023]
Affiliation(s)
- Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
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