1
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Liu L, Fan Z, Rovira X, Xue L, Roux S, Brabet I, Xin M, Pin JP, Rondard P, Liu J. Allosteric ligands control the activation of a class C GPCR heterodimer by acting at the transmembrane interface. eLife 2021; 10:70188. [PMID: 34866572 PMCID: PMC8700296 DOI: 10.7554/elife.70188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 12/02/2021] [Indexed: 01/02/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are among the most promising drug targets. They often form homo- and heterodimers with allosteric cross-talk between receptor entities, which contributes to fine-tuning of transmembrane signaling. Specifically controlling the activity of GPCR dimers with ligands is a good approach to clarify their physiological roles and validate them as drug targets. Here, we examined the mode of action of positive allosteric modulators (PAMs) that bind at the interface of the transmembrane domains of the heterodimeric GABAB receptor. Our site-directed mutagenesis results show that mutations of this interface impact the function of the three PAMs tested. The data support the inference that they act at the active interface between both transmembrane domains, the binding site involving residues of the TM6s of the GABAB1 and the GABAB2 subunit. Importantly, the agonist activity of these PAMs involves a key region in the central core of the GABAB2 transmembrane domain, which also controls the constitutive activity of the GABAB receptor. This region corresponds to the sodium ion binding site in class A GPCRs that controls the basal state of the receptors. Overall, these data reveal the possibility of developing allosteric compounds able to specifically modulate the activity of GPCR homo- and heterodimers by acting at their transmembrane interface.
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Affiliation(s)
- Lei Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Zhiran Fan
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xavier Rovira
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Li Xue
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Salomé Roux
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Isabelle Brabet
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Mingxia Xin
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jianfeng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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2
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Allosteric interactions via the orthosteric ligand binding sites in a constitutive G-protein-coupled receptor homodimer. Pharmacol Res 2020; 166:105116. [PMID: 32783977 DOI: 10.1016/j.phrs.2020.105116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 11/23/2022]
Abstract
I interpret some recent data to indicate that co-operative effects take place between the (identical) orthosteric binding sites in a G-protein-coupled receptor dimer. In the current study, the reasonability of this concept was tested by creating a mathematical model. The model is composed of a symmetrical constitutive receptor dimer in which the protomers are able to affect each other allosterically, and it includes binding, receptor activation and signal amplification steps. The model was utilized for analyses of previous data as well as simulations of predicted behaviour. The model demonstrates the behaviour stated in the hypotheses, i.e. even an apparently neutral receptor ligand can allosterically affect agonist binding or receptor activation by binding to the normal orthosteric ligand binding site. Therewith the speculated allosteric action originating from the orthosteric binding site of the dimeric receptor is a realistic possibility. The results of the simulations and curve fitting constitute a reasonable starting point for further studies, and the model can be utilized to design meaningful experiments to investigate these questions.
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3
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Lans I, Díaz Ó, Dalton JAR, Giraldo J. Exploring the Activation Mechanism of the mGlu5 Transmembrane Domain. Front Mol Biosci 2020; 7:38. [PMID: 32211419 PMCID: PMC7069277 DOI: 10.3389/fmolb.2020.00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/18/2020] [Indexed: 01/14/2023] Open
Abstract
As a class C GPCR and regulator of synaptic activity, mGlu5 is an attractive drug target, potentially offering treatment for several neurologic and psychiatric disorders. As little is known about the activation mechanism of mGlu5 at a structural level, potential of mean force calculations linked to molecular dynamics simulations were performed on the mGlu5 transmembrane domain crystal structure to explore various internal mechanisms responsible for its activation. Our results suggest that the hydrophilic interactions between intracellular loop 1 and the intracellular side of TM6 have to be disrupted to reach a theoretically active-like conformation. In addition, interactions between residues that are key for mGlu5 activation (Tyr6593.44 and Ile7515.51) and mGlu5 inactivation (Tyr6593.44 and Ser8097.39) have been identified. Inasmuch as mGlu5 receptor signaling is poorly understood, potentially showing a complex network of micro-switches and subtle structure-activity relationships, the present study represents a step forward in the understanding of mGlu5 transmembrane domain activation.
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Affiliation(s)
- Isaias Lans
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística and Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Biophysics of Tropical Diseases, Max Planck Tandem Group, University of Antioquia, Medellín, Colombia
| | - Óscar Díaz
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística and Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain
| | - James A R Dalton
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística and Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain
| | - Jesús Giraldo
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística and Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain
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4
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Casadó-Anguera V, Moreno E, Mallol J, Ferré S, Canela EI, Cortés A, Casadó V. Reinterpreting anomalous competitive binding experiments within G protein-coupled receptor homodimers using a dimer receptor model. Pharmacol Res 2018; 139:337-347. [PMID: 30472462 DOI: 10.1016/j.phrs.2018.11.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/14/2018] [Accepted: 11/21/2018] [Indexed: 12/01/2022]
Abstract
An increasing number of G protein-coupled receptors (GPCRs) have been reported to be expressed in the plasma membrane as dimers. Since most ligand binding data are currently fitted by classical equations developed only for monomeric receptors, the interpretation of data could be misleading in the presence of GPCR dimers. On the other hand, the equations developed from dimer receptor models assuming the existence of two orthosteric binding sites within the dimeric molecule offer the possibility to directly calculate macroscopic equilibrium dissociation constants for the two sites, an index of cooperativity (DC) that reflects the molecular communication within the dimer and, importantly, a constant of radioligand-competitor allosteric interaction (KDAB) in competitive assays. Here, we provide a practical way to fit competitive binding data that allows the interpretation of apparently anomalous results, such as competition curves that could be either bell-shaped, monophasic or biphasic depending on the assay conditions. The consideration of a radioligand-competitor allosteric interaction allows fitting these curve patterns both under simulation conditions and in real radioligand binding experiments, obtaining competitor affinity parameters closer to the actual values. Our approach is the first that, assuming the formation of receptor homodimers, is able to explain several experimental results previously considered erroneous due to their impossibility to be fitted. We also deduce the radioligand concentration responsible for the conversion of biphasic to monophasic or to bell-shaped curves in competitive radioligand binding assays. In conclusion, bell-shaped curves in competitive binding experiments constitute evidence for GPCR homodimerization.
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Affiliation(s)
- Verònica Casadó-Anguera
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Estefanía Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Sergi Ferré
- National Institute on Drug Abuse, I.R.P., N.I.H., D.H.H.S., Baltimore, MD, 21224, USA.
| | - Enric I Canela
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
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5
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An operational model for GPCR homodimers and its application in the analysis of biased signaling. Drug Discov Today 2018; 23:1591-1595. [DOI: 10.1016/j.drudis.2018.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 11/23/2022]
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6
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Zhou B, Giraldo J. Quantifying the allosteric interactions within a G-protein-coupled receptor heterodimer. Drug Discov Today 2017; 23:7-11. [PMID: 28756203 DOI: 10.1016/j.drudis.2017.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/26/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022]
Abstract
G-protein-coupled receptors are central to signal transduction and cell communication. The possibility that cells use receptor heteromerization to modulate individual receptor pathways is a surmise that cannot be precluded. Given the complexity of these processes, mathematical models contribute to understanding how receptors and their respective ligands regulate signaling. Here, a mathematical model is presented that quantifies the allosteric interactions within a receptor heterodimer. The model is based on the operational model of allosterism including constitutive receptor activity, which provides the pharmacological analysis of heteromerization with well-established and widely used modeling and fitting procedures.
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Affiliation(s)
- Bin Zhou
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jesús Giraldo
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; Network Biomedical Research Center on Mental Health (CIBERSAM), Spain.
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7
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Moreno Delgado D, Møller TC, Ster J, Giraldo J, Maurel D, Rovira X, Scholler P, Zwier JM, Perroy J, Durroux T, Trinquet E, Prezeau L, Rondard P, Pin JP. Pharmacological evidence for a metabotropic glutamate receptor heterodimer in neuronal cells. eLife 2017; 6. [PMID: 28661401 PMCID: PMC5540479 DOI: 10.7554/elife.25233] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 06/26/2017] [Indexed: 12/25/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are mandatory dimers playing important roles in regulating CNS function. Although assumed to form exclusive homodimers, 16 possible heterodimeric mGluRs have been proposed but their existence in native cells remains elusive. Here, we set up two assays to specifically identify the pharmacological properties of rat mGlu heterodimers composed of mGlu2 and 4 subunits. We used either a heterodimer-specific conformational LRET-based biosensor or a system that guarantees the cell surface targeting of the heterodimer only. We identified mGlu2-4 specific pharmacological fingerprints that were also observed in a neuronal cell line and in lateral perforant path terminals naturally expressing mGlu2 and mGlu4. These results bring strong evidence for the existence of mGlu2-4 heterodimers in native cells. In addition to reporting a general approach to characterize heterodimeric mGluRs, our study opens new avenues to understanding the pathophysiological roles of mGlu heterodimers. DOI:http://dx.doi.org/10.7554/eLife.25233.001
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Affiliation(s)
- David Moreno Delgado
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Thor C Møller
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Jeanne Ster
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Jesús Giraldo
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Network Biomedical Research Center on Mental Health, Madrid, Spain
| | - Damien Maurel
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Pauline Scholler
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | | | - Julie Perroy
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | | | - Laurent Prezeau
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Univ. Montpellier, Montpellier, France
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8
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Sengmany K, Gregory KJ. Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias. Br J Pharmacol 2015; 173:3001-17. [PMID: 26276909 DOI: 10.1111/bph.13281] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/30/2015] [Accepted: 07/26/2015] [Indexed: 12/12/2022] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGlu5 ) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR-based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine-tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus-bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- K Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - K J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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9
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Dalton JAR, Gómez-Santacana X, Llebaria A, Giraldo J. Computational analysis of negative and positive allosteric modulator binding and function in metabotropic glutamate receptor 5 (in)activation. J Chem Inf Model 2014; 54:1476-87. [PMID: 24793143 DOI: 10.1021/ci500127c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are high-profile G-protein coupled receptors drug targets because of their involvement in several neurological disease states, and mGluR5 in particular is a subtype whose controlled allosteric modulation, both positive and negative, can potentially be useful for the treatment of schizophrenia and relief of chronic pain, respectively. Here we model mGluR5 with a collection of positive and negative allosteric modulators (PAMs and NAMs) in both active and inactive receptor states, in a manner that is consistent with experimental information, using a specialized protocol that includes homology to increase docking accuracy, and receptor relaxation to generate an individual induced fit with each allosteric modulator. Results implicate two residues in particular for NAM and PAM function: NAM interaction with W785 for receptor inactivation, and NAM/PAM H-bonding with S809 for receptor (in)activation. Models suggest the orientation of the H-bond between allosteric modulator and S809, controlled by PAM/NAM chemistry, influences the position of TM7, which in turn influences the shape of the allosteric site, and potentially the receptor state. NAM-bound and PAM-bound mGluR5 models also reveal that although PAMs and NAMs bind in the same pocket and share similar binding modes, they have distinct effects on the conformation of the receptor. Our models, together with the identification of a possible activation mechanism, may be useful in the rational design of new allosteric modulators for mGluR5.
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Affiliation(s)
- James A R Dalton
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona, Spain
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10
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Agliari E, Barra A, Burioni R, Di Biasio A, Uguzzoni G. Collective behaviours: from biochemical kinetics to electronic circuits. Sci Rep 2013; 3:3458. [PMID: 24322327 PMCID: PMC3857571 DOI: 10.1038/srep03458] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/20/2013] [Indexed: 11/09/2022] Open
Abstract
In this work we aim to highlight a close analogy between cooperative behaviors in chemical kinetics and cybernetics; this is realized by using a common language for their description, that is mean-field statistical mechanics. First, we perform a one-to-one mapping between paradigmatic behaviors in chemical kinetics (i.e., non-cooperative, cooperative, ultra-sensitive, anti-cooperative) and in mean-field statistical mechanics (i.e., paramagnetic, high and low temperature ferromagnetic, anti-ferromagnetic). Interestingly, the statistical mechanics approach allows a unified, broad theory for all scenarios and, in particular, Michaelis-Menten, Hill and Adair equations are consistently recovered. This framework is then tested against experimental biological data with an overall excellent agreement. One step forward, we consistently read the whole mapping from a cybernetic perspective, highlighting deep structural analogies between the above-mentioned kinetics and fundamental bricks in electronics (i.e. operational amplifiers, flashes, flip-flops), so to build a clear bridge linking biochemical kinetics and cybernetics.
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Affiliation(s)
- Elena Agliari
- 1] Dipartimento di Fisica, Università degli Studi di Parma, viale G. Usberti 7, 43100 Parma, Italy [2] INFN, Gruppo Collegato di Parma, viale G. Usberti 7, 43100 Parma, Italy
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11
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Bindslev N. Allosteric transition: a comparison of two models. BMC Pharmacol Toxicol 2013; 14:4. [PMID: 23298758 PMCID: PMC3599370 DOI: 10.1186/2050-6511-14-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 12/10/2012] [Indexed: 11/10/2022] Open
Abstract
Introduction Two recent models are in use for analysis of allosteric drug action at receptor sites remote from orthosteric binding sites. One is an allosteric two-state mechanical model derived in 2000 by David Hall. The other is an extended operational model developed in 2007 by Arthur Christopoulos’s group. The models are valid in pharmacology, enzymology, transportology as well as several other fields of biology involving allosteric concentration effects. Results I show here that Hall’s model for interactions between an orthoster, an alloster, and a receptive unit is the best choice of model both for simulation and analysis of allosteric concentration-responses at equilibrium or steady-state. Conclusions As detailed knowledge of receptors systems becomes available, systems with several pathways and states and/ or more than two binding sites should be analysed by extended forms of the Hall model rather than for instance a Hill type exponentiation of terms as introduced in non-mechanistic (operational) model approaches; yielding semi-quantitative estimates of actual system parameters based on Hill’s unlikely simultaneity model for G protein-coupled receptors.
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Affiliation(s)
- Niels Bindslev
- Synagics Lab, Endocrinology Section, Department of Biomedical Sciences, The Medical Faculty, Panum Building, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark.
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12
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Giraldo J. Modeling cooperativity effects in dimeric G protein-coupled receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:349-73. [PMID: 23415098 DOI: 10.1016/b978-0-12-394587-7.00008-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
G protein-coupled receptors organize into oligomeric arrangements to exert their function. In this chapter, three models of dimeric receptors, the two-state dimer receptor model, the metabotropic glutamate receptor model, and the asymmetric/symmetric three-state dimer receptor model are revisited focusing on the cooperative effects between their binding sites and the subunits they are composed of. The mathematical analysis reveals the complexity of the intra-receptor interactions providing insights on the mechanistic aspects of receptor function.
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Affiliation(s)
- Jesús Giraldo
- Laboratory of Systems Pharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain
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13
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Amalric M, Lopez S, Goudet C, Fisone G, Battaglia G, Nicoletti F, Pin JP, Acher FC. Group III and subtype 4 metabotropic glutamate receptor agonists: discovery and pathophysiological applications in Parkinson's disease. Neuropharmacology 2012; 66:53-64. [PMID: 22664304 DOI: 10.1016/j.neuropharm.2012.05.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 04/28/2012] [Accepted: 05/21/2012] [Indexed: 12/22/2022]
Abstract
Restoring the balance between excitatory and inhibitory circuits in the basal ganglia, following the loss of dopaminergic (DA) neurons of the substantia nigra pars compacta, represents a major challenge to treat patients affected by Parkinson's disease (PD). The imbalanced situation in favor of excitation in the disease state may also accelerate excitotoxic processes, thereby representing a potential target for neuroprotective therapies. Reducing the excitatory action of glutamate, the major excitatory neurotransmitter in the basal ganglia, should lead to symptomatic improvement for PD patients and may promote the survival of DA neurons. Recent studies have focused on the modulatory action of metabotropic glutamate (mGlu) receptors on neurodegenerative diseases including PD. Group III mGlu receptors, including subtypes 4, 7 and 8, are largely expressed in the basal ganglia. Recent studies highlight the use of selective mGlu4 receptor positive allosteric modulators (PAMs) for the treatment of PD. Here we review the effects of newly-designed group-III orthosteric agonists on neuroprotection, neurorestoration and reduction of l-DOPA induced dyskinesia in animal models of PD. The combination of orthosteric mGlu4 receptor selective agonists with PAMs may open new avenues for the symptomatic treatment of PD. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- M Amalric
- Aix-Marseille University, CNRS UMR 7291, Laboratoire de Neurosciences Fonctionnelles, Case C, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France.
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Agnati LF, Guidolin D, Leo G, Guescini M, Pizzi M, Stocchi V, Spano PF, Ghidoni R, Ciruela F, Genedani S, Fuxe K. Possible new targets for GPCR modulation: allosteric interactions, plasma membrane domains, intercellular transfer and epigenetic mechanisms. J Recept Signal Transduct Res 2012; 31:315-31. [PMID: 21929287 DOI: 10.3109/10799893.2011.599393] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It has been estimated that at least 50% of the drugs available on the market act on G-protein coupled receptors (GPCRs) and most of these are basically or agonists or antagonists of this type of receptors. Herein, we propose new putative targets for drug development based on recent data on GPCR allosterism and on the existence of receptor mosaics (RMs). The main target for drug development is still GPCRs, but the focus is not the orthosteric binding pocket. According to the mosaic model of the plasma membrane, we mainly discuss the possibility of indirect modulatory pharmacological actions on expression/function of GPCRs. In particular, the following two new targets will be analyzed: a) The possibility of pharmacological interventions on the roamer-type of volume transmission (VT), which allow the intercellular transfer of set of signal molecules such as GPCRs, tetraspanins and ribonucleic acids. Thus, there is the possibility of pharmacological interventions on the decoding capabilities of neurons and/or glial cells by means of an action on composition and release of micro-vesicles. b) The possibility of pharmacological interventions on epigenetic mechanisms by taking into account their inter-relationships with GPCRs. As a matter of fact, there are epigenetic changes that are characteristic of periods of developmental plasticity that could provide a target for therapeutic intervention in the event of brain damage. We believe that almost all the biochemical knowledge presently available on GPCRs can be used in the development of these new pharmacological approaches.
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15
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Guidolin D, Ciruela F, Genedani S, Guescini M, Tortorella C, Albertin G, Fuxe K, Agnati LF. Bioinformatics and mathematical modelling in the study of receptor–receptor interactions and receptor oligomerization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1267-83. [DOI: 10.1016/j.bbamem.2010.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/31/2010] [Accepted: 09/26/2010] [Indexed: 10/19/2022]
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16
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The asymmetric/symmetric activation of GPCR dimers as a possible mechanistic rationale for multiple signalling pathways. Trends Pharmacol Sci 2010; 31:15-21. [DOI: 10.1016/j.tips.2009.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 11/16/2022]
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17
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Bird MK, Lawrence AJ. The promiscuous mGlu5 receptor--a range of partners for therapeutic possibilities? Trends Pharmacol Sci 2009; 30:617-23. [PMID: 19892412 DOI: 10.1016/j.tips.2009.09.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 09/23/2009] [Accepted: 09/23/2009] [Indexed: 01/20/2023]
Abstract
The issue of non-specific effects for potential therapeutics is particularly salient in neurological/psychiatric disorders, where adverse drug reactions could impair critical brain functions. The issue of specificity is not limited to candidate molecules, as receptor targets themselves often influence physiological as well as pathological outcomes. Metabotropic glutamate receptor 5 (mGlu5) is an example of a "promiscuous" receptor target that has been implicated in addiction, but also many other processes. However, if receptor modulation could be restricted to specific pathways/brain regions, mGlu5 may still prove to be a viable therapeutic target for various indications. Using this premise, a number of possible methods to refine drug development strategy are discussed, including exploiting specific interactions of mGlu5 with other receptors to narrow the influence of pharmacological agents, and also the use of RNA interference targeted to specific cells/regions of the brain.
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Affiliation(s)
- Michael K Bird
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, 3010, Australia
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18
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Rovira X, Vivó M, Serra J, Roche D, Strange PG, Giraldo J. Modelling the interdependence between the stoichiometry of receptor oligomerization and ligand binding for a coexisting dimer/tetramer receptor system. Br J Pharmacol 2009; 156:28-35. [PMID: 19133989 DOI: 10.1111/j.1476-5381.2008.00031.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Many G protein-coupled receptors have been shown to exist as oligomers, but the oligomerization state and the effects of this on receptor function are unclear. For some G protein-coupled receptors, in ligand binding assays, different radioligands provide different maximal binding capacities. Here we have developed mathematical models for co-expressed dimeric and tetrameric species of receptors. We have considered models where the dimers and tetramers are in equilibrium and where they do not interconvert and we have also considered the potential influence of the ligands on the degree of oligomerization. By analogy with agonist efficacy, we have considered ligands that promote, inhibit or have no effect on oligomerization. Cell surface receptor expression and the intrinsic capacity of receptors to oligomerize are quantitative parameters of the equations. The models can account for differences in the maximal binding capacities of radioligands in different preparations of receptors and provide a conceptual framework for simulation and data fitting in complex oligomeric receptor situations.
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Affiliation(s)
- X Rovira
- Grup Biomatemàtic de Recerca, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Giraldo J. On the fitting of binding data when receptor dimerization is suspected. Br J Pharmacol 2008; 155:17-23. [PMID: 18536745 DOI: 10.1038/bjp.2008.234] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mechanistic and empirical modelling are compared in context of dimeric receptors. In particular, the supposed advantages of the two-state dimer model for fitting of binding data with respect to classical approaches such as the two-independent sites model are investigated. The two models are revisited from both the mechanistic and empirical point of views. The problem of overparameterized models and the benefits of the concurrent use of mechanistic and empirical models for mechanism analysis are discussed. The pros and cons of mathematical models are examined with special emphasis given to the interpretation of the connection between the shapes of the curves and receptor cooperativity. It is shown that a given pharmacological phenotype (curve shape) can be obtained from different receptor genotypes (as, for instance, non-interconvertible monomeric receptor species, receptor-G protein interactions and dimeric receptors), though values of the Hill coefficient greater than one are indicative of receptor oligomerization. The existence of a relationship between the recently defined dimer cooperativity index and the more familiar Hill coefficient is proven.
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Affiliation(s)
- J Giraldo
- Grup Biomatemàtic de Recerca, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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