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Zhang M, Chen T, Lu X, Lan X, Chen Z, Lu S. G protein-coupled receptors (GPCRs): advances in structures, mechanisms, and drug discovery. Signal Transduct Target Ther 2024; 9:88. [PMID: 38594257 PMCID: PMC11004190 DOI: 10.1038/s41392-024-01803-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 02/19/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024] Open
Abstract
G protein-coupled receptors (GPCRs), the largest family of human membrane proteins and an important class of drug targets, play a role in maintaining numerous physiological processes. Agonist or antagonist, orthosteric effects or allosteric effects, and biased signaling or balanced signaling, characterize the complexity of GPCR dynamic features. In this study, we first review the structural advancements, activation mechanisms, and functional diversity of GPCRs. We then focus on GPCR drug discovery by revealing the detailed drug-target interactions and the underlying mechanisms of orthosteric drugs approved by the US Food and Drug Administration in the past five years. Particularly, an up-to-date analysis is performed on available GPCR structures complexed with synthetic small-molecule allosteric modulators to elucidate key receptor-ligand interactions and allosteric mechanisms. Finally, we highlight how the widespread GPCR-druggable allosteric sites can guide structure- or mechanism-based drug design and propose prospects of designing bitopic ligands for the future therapeutic potential of targeting this receptor family.
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Affiliation(s)
- Mingyang Zhang
- Key Laboratory of Protection, Development and Utilization of Medicinal Resources in Liupanshan Area, Ministry of Education, Peptide & Protein Drug Research Center, School of Pharmacy, Ningxia Medical University, Yinchuan, 750004, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Ting Chen
- Department of Cardiology, Changzheng Hospital, Affiliated to Naval Medical University, Shanghai, 200003, China
| | - Xun Lu
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiaobing Lan
- Key Laboratory of Protection, Development and Utilization of Medicinal Resources in Liupanshan Area, Ministry of Education, Peptide & Protein Drug Research Center, School of Pharmacy, Ningxia Medical University, Yinchuan, 750004, China
| | - Ziqiang Chen
- Department of Orthopedics, Changhai Hospital, Affiliated to Naval Medical University, Shanghai, 200433, China.
| | - Shaoyong Lu
- Key Laboratory of Protection, Development and Utilization of Medicinal Resources in Liupanshan Area, Ministry of Education, Peptide & Protein Drug Research Center, School of Pharmacy, Ningxia Medical University, Yinchuan, 750004, China.
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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2
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Shivnaraine RV, Kelly B, Elmslie G, Huang XP, Dong YJ, Seidenberg M, Wells JW, Ellis J. Allostery of atypical modulators at oligomeric G protein-coupled receptors. Sci Rep 2021; 11:9265. [PMID: 33927236 PMCID: PMC8085029 DOI: 10.1038/s41598-021-88399-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/06/2021] [Indexed: 01/14/2023] Open
Abstract
Many G protein-coupled receptors (GPCRs) are therapeutic targets, with most drugs acting at the orthosteric site. Some GPCRs also possess allosteric sites, which have become a focus of drug discovery. In the M2 muscarinic receptor, allosteric modulators regulate the binding and functional effects of orthosteric ligands through a mix of conformational changes, steric hindrance and electrostatic repulsion transmitted within and between the constituent protomers of an oligomer. Tacrine has been called an atypical modulator because it exhibits positive cooperativity, as revealed by Hill coefficients greater than 1 in its negative allosteric effect on binding and response. Radioligand binding and molecular dynamics simulations were used to probe the mechanism of that modulation in monomers and oligomers of wild-type and mutant M2 receptors. Tacrine is not atypical at monomers, which indicates that its atypical effects are a property of the receptor in its oligomeric state. These results illustrate that oligomerization of the M2 receptor has functional consequences.
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Affiliation(s)
- Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada.
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, B163 Beckman Center, 279 Campus Drive, Stanford, CA, 94305, USA.
| | - Brendan Kelly
- Departments of Computer Science, Molecular and Cellular Physiology, and Structural Biology, and Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Gwendolynne Elmslie
- Departments of Psychiatry and Pharmacology, Hershey Medical Center, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - Xi-Ping Huang
- Departments of Psychiatry and Pharmacology, Hershey Medical Center, Penn State University College of Medicine, Hershey, PA, 17033, USA
- Department of Pharmacology, The National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yue John Dong
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - Margaret Seidenberg
- Departments of Psychiatry and Pharmacology, Hershey Medical Center, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - James W Wells
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada.
| | - John Ellis
- Departments of Psychiatry and Pharmacology, Hershey Medical Center, Penn State University College of Medicine, Hershey, PA, 17033, USA.
- Department of Psychiatry H073, Penn State University College of Medicine, 500 University Drive, Hershey, PA, 17033, USA.
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3
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A general method to quantify ligand-driven oligomerization from fluorescence-based images. Nat Methods 2019; 16:493-496. [PMID: 31110281 DOI: 10.1038/s41592-019-0408-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/02/2019] [Indexed: 01/30/2023]
Abstract
Here, we introduce fluorescence intensity fluctuation spectrometry for determining the identity, abundance and stability of protein oligomers. This approach was tested on monomers and oligomers of known sizes and was used to uncover the oligomeric states of the epidermal growth factor receptor and the secretin receptor in the presence and absence of their agonist ligands. This method is fast and is scalable for high-throughput screening of drugs targeting protein-protein interactions.
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Sleno R, Hébert TE. Shaky ground - The nature of metastable GPCR signalling complexes. Neuropharmacology 2019; 152:4-14. [PMID: 30659839 DOI: 10.1016/j.neuropharm.2019.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/20/2018] [Accepted: 01/16/2019] [Indexed: 01/19/2023]
Abstract
How G protein-coupled receptors (GPCR) interact with one another remains an area of active investigation. Obligate dimers of class C GPCRs such as metabotropic GABA and glutamate receptors are well accepted, although whether this is a general feature of other GPCRs is still strongly debated. In this review, we focus on the idea that GPCR dimers and oligomers are better imagined as parts of larger metastable signalling complexes. We discuss the nature of functional oligomeric entities, their stabilities and kinetic features and how structural and functional asymmetries of such metastable entities might have implications for drug discovery. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.
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Affiliation(s)
- Rory Sleno
- Marketed Pharmaceuticals and Medical Devices Bureau, Marketed Health Products Directorate, Health Products and Food Branch, Health Canada, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Canada.
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5
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. Receptor-Receptor Interactions as a Widespread Phenomenon: Novel Targets for Drug Development? Front Endocrinol (Lausanne) 2019; 10:53. [PMID: 30833931 PMCID: PMC6387912 DOI: 10.3389/fendo.2019.00053] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
The discovery of receptor-receptor interactions (RRI) has expanded our understanding of the role that G protein-coupled receptors (GPCRs) play in intercellular communication. The finding that GPCRs can operate as receptor complexes, and not only as monomers, suggests that several different incoming signals could already be integrated at the plasma membrane level via direct allosteric interactions between the protomers that form the complex. Most research in this field has focused on neuronal populations and has led to the identification of a large number of RRI. However, RRI have been seen to occur not only in neurons but also in astrocytes and, outside the central nervous system, in cells of the cardiovascular and endocrine systems and in cancer cells. Furthermore, RRI involving the formation of macromolecular complexes are not limited to GPCRs, being also observed in other families of receptors. Thus, RRI appear as a widespread phenomenon and oligomerization as a common mechanism for receptor function and regulation. The discovery of these macromolecular assemblies may well have a major impact on pharmacology. Indeed, the formation of receptor complexes significantly broadens the spectrum of mechanisms available to receptors for recognition and signaling, which may be implemented through modulation of the binding sites of the adjacent protomers and of their signal transduction features. In this context, the possible appearance of novel allosteric sites in the receptor complex structure may be of particular relevance. Thus, the existence of RRI offers the possibility of new therapeutic approaches, and novel pharmacological strategies for disease treatment have already been proposed. Several challenges, however, remain. These include the accurate characterization of the role that the receptor complexes identified so far play in pathological conditions and the development of ligands specific to given receptor complexes, in order to efficiently exploit the pharmacological properties of these complexes.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, University of Padova, Padova, Italy
- *Correspondence: Diego Guidolin
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | | | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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6
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Burger WAC, Sexton PM, Christopoulos A, Thal DM. Toward an understanding of the structural basis of allostery in muscarinic acetylcholine receptors. J Gen Physiol 2018; 150:1360-1372. [PMID: 30190312 PMCID: PMC6168235 DOI: 10.1085/jgp.201711979] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/14/2018] [Indexed: 01/16/2023] Open
Abstract
Burger et al. summarize our mechanistic understanding of allostery in the prototypical GPCR, the muscarinic acetylcholine receptor. Recent breakthroughs and developments in structural biology have led to a spate of crystal structures for G protein–coupled receptors (GPCRs). This is the case for the muscarinic acetylcholine receptors (mAChRs) where inactive-state structures for four of the five subtypes and two active-state structures for one subtype are available. These mAChR crystal structures have provided new insights into receptor mechanisms, dynamics, and allosteric modulation. This is highly relevant to the mAChRs given that these receptors are an exemplar model system for the study of GPCR allostery. Allosteric mechanisms of the mAChRs are predominantly consistent with a two-state model, albeit with some notable recent exceptions. Herein, we discuss the mechanisms for positive and negative allosteric modulation at the mAChRs and compare and contrast these to evidence offered by pharmacological, biochemical, and computational approaches. This analysis provides insight into the fundamental pharmacological properties exhibited by GPCR allosteric modulators, such as enhanced subtype selectivity, probe dependence, and biased modulation while highlighting the current challenges that remain. Though complex, enhanced molecular understanding of allosteric mechanisms will have considerable influence on our understanding of GPCR activation and signaling and development of therapeutic interventions.
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Affiliation(s)
- Wessel A C Burger
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - David M Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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7
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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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8
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Li Y, Shivnaraine RV, Huang F, Wells JW, Gradinaru CC. Ligand-Induced Coupling between Oligomers of the M 2 Receptor and the G i1 Protein in Live Cells. Biophys J 2018; 115:881-895. [PMID: 30131171 DOI: 10.1016/j.bpj.2018.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/23/2018] [Accepted: 08/02/2018] [Indexed: 02/07/2023] Open
Abstract
Uncertainty over the mechanism of signaling via G protein-coupled receptors (GPCRs) relates in part to questions regarding their supramolecular structure. GPCRs and heterotrimeric G proteins are known to couple as monomers under various conditions. Many GPCRs form oligomers under many of the same conditions, however, and the biological role of those complexes is unclear. We have used dual-color fluorescence correlation spectroscopy to identify oligomers of the M2 muscarinic receptor and of Gi1 in purified preparations and live Chinese hamster ovary cells. Measurements on differently tagged receptors (i.e., eGFP-M2 and mCherry-M2) and G proteins (i.e., eGFP-Gαi1β1γ2 and mCherry-Gαi1β1γ2) detected significant cross-correlations between the two fluorophores in each case, both in detergent micelles and in live cells, indicating that both the receptor and Gi1 can exist as homo-oligomers. Oligomerization of differently tagged Gi1 decreased upon the activation of co-expressed wild-type M2 receptor by an agonist. Measurements on a tagged M2 receptor (M2-mCherry) and eGFP-Gαi1β1γ2 co-expressed in live cells detected cross-correlations only in the presence of an agonist, which therefore promoted coupling of the receptor and the G protein. The effect of the agonist was retained when a fluorophore-tagged receptor lacking the orthosteric site (i.e., M2(D103A)-mCherry) was co-expressed with the wild-type receptor and eGFP-Gαi1β1γ2, indicating that the ligand acted via an oligomeric receptor. Our results point to a model in which an agonist promotes transient coupling of otherwise independent oligomers of the M2 receptor on the one hand and of Gi1 on the other and that an activated complex leads to a reduction in the oligomeric size of the G protein. They suggest that GPCR-mediated signaling proceeds, at least in part, via oligomers.
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Affiliation(s)
- Yuchong Li
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Fei Huang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - James W Wells
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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9
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Marsango S, Ward RJ, Alvarez-Curto E, Milligan G. Muscarinic receptor oligomerization. Neuropharmacology 2018; 136:401-410. [PMID: 29146505 PMCID: PMC6078712 DOI: 10.1016/j.neuropharm.2017.11.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 11/01/2017] [Accepted: 11/13/2017] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) have been classically described as monomeric entities that function by binding in a 1:1 stoichiometric ratio to both ligand and downstream signalling proteins. However, in recent years, a growing number of studies has supported the hypothesis that these receptors can interact to form dimers and higher order oligomers although the molecular basis for these interactions, the overall quaternary arrangements and the functional importance of GPCR oligomerization remain topics of intense speculation. Muscarinic acetylcholine receptors belong to class A of the GPCR family. Each muscarinic receptor subtype has its own particular distribution throughout the central and peripheral nervous systems. In the central nervous system, muscarinic receptors regulate several sensory, cognitive, and motor functions while, in the peripheral nervous system, they are involved in the regulation of heart rate, stimulation of glandular secretion and smooth muscle contraction. Muscarinic acetylcholine receptors have long been used as a model for the study of GPCR structure and function and to address aspects of GPCR dimerization using a broad range of approaches. In this review, the prevailing knowledge regarding the quaternary arrangement for the various muscarinic acetylcholine receptors has been summarized by discussing work ranging from initial results obtained using more traditional biochemical approaches to those generated with more modern biophysical techniques. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- Sara Marsango
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
| | - Richard J Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
| | - Elisa Alvarez-Curto
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Graeme Milligan
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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10
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Gurevich VV, Gurevich EV. GPCRs and Signal Transducers: Interaction Stoichiometry. Trends Pharmacol Sci 2018; 39:672-684. [PMID: 29739625 DOI: 10.1016/j.tips.2018.04.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/11/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022]
Abstract
Until the late 1990s, class A G protein-coupled receptors (GPCRs) were believed to function as monomers. Indirect evidence that they might internalize or even signal as dimers has emerged, along with proof that class C GPCRs are obligatory dimers. Crystal structures of GPCRs and their much larger binding partners were consistent with the idea that two receptors might engage a single G protein, GRK, or arrestin. However, recent biophysical, biochemical, and structural evidence invariably suggests that a single GPCR binds G proteins, GRKs, and arrestins. Here we review existing evidence of the stoichiometry of GPCR interactions with signal transducers and discuss potential biological roles of class A GPCR oligomers, including proposed homo- and heterodimers.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Eugenia V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
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Sleno R, Hébert TE. The Dynamics of GPCR Oligomerization and Their Functional Consequences. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:141-171. [PMID: 29699691 DOI: 10.1016/bs.ircmb.2018.02.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The functional importance of G protein-coupled receptor (GPCR) oligomerization remains controversial. Although obligate dimers of class C GPCRs are well accepted, the generalizability of this phenomenon is still strongly debated with respect to other classes of GPCRs. In this review, we focus on understanding the organization and dynamics between receptor equivalents and their signaling partners in oligomeric receptor complexes, with a view toward integrating disparate viewpoints into a unified understanding. We discuss the nature of functional oligomeric entities, and how asymmetries in receptor structure and function created by oligomers might have implications for receptor function as allosteric machines and for future drug discovery.
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12
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Jacobs BA, Pando MM, Jennings E, Chavera TA, Clarke WP, Berg KA. Allosterism within δ Opioid- κ Opioid Receptor Heteromers in Peripheral Sensory Neurons: Regulation of κ Opioid Agonist Efficacy. Mol Pharmacol 2018; 93:376-386. [PMID: 29436492 PMCID: PMC5832326 DOI: 10.1124/mol.117.109975] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 02/01/2018] [Indexed: 11/22/2022] Open
Abstract
There is abundant evidence for formation of G protein-coupled receptor heteromers in heterologous expression systems, but little is known of the function of heteromers in native systems. Heteromers of δ and κ opioid receptors (DOR-KOR heteromers) have been identified in native systems. We previously reported that activation of DOR-KOR heteromers expressed by rat pain-sensing neurons (nociceptors) produces robust, peripherally mediated antinociception. Moreover, DOR agonist potency and efficacy is regulated by KOR antagonists via allosteric interactions within the DOR-KOR heteromer in a ligand-dependent manner. Here we assessed the reciprocal regulation of KOR agonist function by DOR antagonists in adult rat nociceptors in culture and in a behavioral assay of nociception. Naltrindole enhanced the potency of the KOR agonist 2-(3,4-dichlorophenyl)-N-methyl-N-[(1S)-1-phenyl-2-pyrrolidin-1-ylethyl]acetamide (ICI-199441) 10- to 20-fold, but did not alter responses to 2-(3,4-dichlorophenyl)-N-methyl-N-[(1R,2R)-2-pyrrolidin-1-ylcyclohexyl]acetamide (U50488). By contrast, the potency of U50488 was enhanced 20-fold by 7-benzylidenenaltrexone. The efficacy of 6'-guanidinonaltrindole (6'-GNTI) to inhibit nociceptors was blocked by small interfering RNA knockdown of DOR or KOR. Replacing 6'-GNTI occupancy of DOR with either naltrindole or 7-benzylidenenaltrexone abolished 6'-GNTI efficacy. Further, peptides derived from DOR transmembrane segment 1 fused to the cell membrane-penetrating HIV transactivator of transcription peptide also blocked 6'-GNTI-mediated responses ex vivo and in vivo, suggesting that 6'-GNTI efficacy in nociceptors is due to its positive allosteric regulation of KOR via occupancy of DOR in a DOR-KOR heteromer. Together, these results provide evidence for the existence of functional DOR-KOR heteromers in rat peripheral sensory neurons and that reciprocal, ligand-dependent allosteric interactions occur between the DOR and KOR protomers.
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MESH Headings
- Allosteric Regulation/drug effects
- Allosteric Regulation/physiology
- Amino Acid Sequence
- Analgesics, Opioid/pharmacology
- Animals
- Cells, Cultured
- Dose-Response Relationship, Drug
- Male
- Peptide Fragments/genetics
- Peptide Fragments/pharmacology
- Peripheral Nerves/drug effects
- Peripheral Nerves/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/physiology
- Sensory Receptor Cells/drug effects
- Sensory Receptor Cells/physiology
- Trigeminal Ganglion/drug effects
- Trigeminal Ganglion/physiology
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Affiliation(s)
- Blaine A Jacobs
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Miryam M Pando
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Elaine Jennings
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Teresa A Chavera
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - William P Clarke
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Kelly A Berg
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. G protein-coupled receptor-receptor interactions give integrative dynamics to intercellular communication. Rev Neurosci 2018; 29:703-726. [DOI: 10.1515/revneuro-2017-0087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/01/2018] [Indexed: 01/14/2023]
Abstract
Abstract
The proposal of receptor-receptor interactions (RRIs) in the early 1980s broadened the view on the role of G protein-coupled receptors (GPCR) in the dynamics of the intercellular communication. RRIs, indeed, allow GPCR to operate not only as monomers but also as receptor complexes, in which the integration of the incoming signals depends on the number, spatial arrangement, and order of activation of the protomers forming the complex. The main biochemical mechanisms controlling the functional interplay of GPCR in the receptor complexes are direct allosteric interactions between protomer domains. The formation of these macromolecular assemblies has several physiologic implications in terms of the modulation of the signaling pathways and interaction with other membrane proteins. It also impacts on the emerging field of connectomics, as it contributes to set and tune the synaptic strength. Furthermore, recent evidence suggests that the transfer of GPCR and GPCR complexes between cells via the exosome pathway could enable the target cells to recognize/decode transmitters and/or modulators for which they did not express the pertinent receptors. Thus, this process may also open the possibility of a new type of redeployment of neural circuits. The fundamental aspects of GPCR complex formation and function are the focus of the present review article.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Cinzia Tortorella
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences , University of Modena and Reggio Emilia , I-41121 Modena , Italy
- Department of Neuroscience , Karolinska Institutet , S-17177 Stockholm , Sweden
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14
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Menzikov SA. Effect of phenol on the GABAAR-coupled Cl−/HCO3−-ATPase from fish brain: An in vitro approach on the enzyme function. Toxicol In Vitro 2018; 46:129-136. [DOI: 10.1016/j.tiv.2017.09.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/24/2017] [Accepted: 09/25/2017] [Indexed: 11/30/2022]
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Fernandes DD, Bamrah J, Kailasam S, Gomes GNW, Li Y, Wieden HJ, Gradinaru CC. Characterization of Fluorescein Arsenical Hairpin (FlAsH) as a Probe for Single-Molecule Fluorescence Spectroscopy. Sci Rep 2017; 7:13063. [PMID: 29026195 PMCID: PMC5638890 DOI: 10.1038/s41598-017-13427-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 09/21/2017] [Indexed: 01/27/2023] Open
Abstract
In recent years, new labelling strategies have been developed that involve the genetic insertion of small amino-acid sequences for specific attachment of small organic fluorophores. Here, we focus on the tetracysteine FCM motif (FLNCCPGCCMEP), which binds to fluorescein arsenical hairpin (FlAsH), and the ybbR motif (TVLDSLEFIASKLA) which binds fluorophores conjugated to Coenzyme A (CoA) via a phosphoryl transfer reaction. We designed a peptide containing both motifs for orthogonal labelling with FlAsH and Alexa647 (AF647). Molecular dynamics simulations showed that both motifs remain solvent-accessible for labelling reactions. Fluorescence spectra, correlation spectroscopy and anisotropy decay were used to characterize labelling and to obtain photophysical parameters of free and peptide-bound FlAsH. The data demonstrates that FlAsH is a viable probe for single-molecule studies. Single-molecule imaging confirmed dual labeling of the peptide with FlAsH and AF647. Multiparameter single-molecule Förster Resonance Energy Transfer (smFRET) measurements were performed on freely diffusing peptides in solution. The smFRET histogram showed different peaks corresponding to different backbone and dye orientations, in agreement with the molecular dynamics simulations. The tandem of fluorophores and the labelling strategy described here are a promising alternative to bulky fusion fluorescent proteins for smFRET and single-molecule tracking studies of membrane proteins.
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Affiliation(s)
- Dennis D Fernandes
- Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada.
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada.
| | - Jasbir Bamrah
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada
| | - Senthilkumar Kailasam
- Alberta RNA Research & Training Institute, Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
| | - Gregory-Neal W Gomes
- Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada
| | - Yuchong Li
- Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada
| | - Hans-Joachim Wieden
- Alberta RNA Research & Training Institute, Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada.
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada.
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Farran B. An update on the physiological and therapeutic relevance of GPCR oligomers. Pharmacol Res 2017; 117:303-327. [PMID: 28087443 DOI: 10.1016/j.phrs.2017.01.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/17/2023]
Abstract
The traditional view on GPCRs held that they function as single monomeric units composed of identical subunits. This notion was overturned by the discovery that GPCRs can form homo- and hetero-oligomers, some of which are obligatory, and can further assemble into receptor mosaics consisting of three or more protomers. Oligomerisation exerts significant impacts on receptor function and physiology, offering a platform for the diversification of receptor signalling, pharmacology, regulation, crosstalk, internalization and trafficking. Given their involvement in the modulation of crucial physiological processes, heteromers could constitute important therapeutic targets for a wide range of diseases, including schizophrenia, Parkinson's disease, substance abuse or obesity. This review aims at depicting the current developments in GPCR oligomerisation research, documenting various class A, B and C GPCR heteromers detected in vitro and in vivo using biochemical and biophysical approaches, as well as recently identified higher-order oligomeric complexes. It explores the current understanding of dimerization dynamics and the possible interaction interfaces that drive oligomerisation. Most importantly, it provides an inventory of the wide range of physiological processes and pathophysiological conditions to which GPCR oligomers contribute, surveying some of the oligomers that constitute potential drug targets. Finally, it delineates the efforts to develop novel classes of ligands that specifically target and tether to receptor oligomers instead of a single monomeric entity, thus ameliorating their ability to modulate GPCR function.
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Affiliation(s)
- Batoul Farran
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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Quaternary structures of opsin in live cells revealed by FRET spectrometry. Biochem J 2016; 473:3819-3836. [PMID: 27623775 DOI: 10.1042/bcj20160422] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
Rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that initiates phototransduction in the retina. The receptor consists of the apoprotein opsin covalently linked to the inverse agonist 11-cis retinal. Rhodopsin and opsin have been shown to form oligomers within the outer segment disc membranes of rod photoreceptor cells. However, the physiological relevance of the observed oligomers has been questioned since observations were made on samples prepared from the retina at low temperatures. To investigate the oligomeric status of opsin in live cells at body temperatures, we utilized a novel approach called Förster resonance energy transfer spectrometry, which previously has allowed the determination of the stoichiometry and geometry (i.e. quaternary structure) of various GPCRs. In the current study, we have extended the method to additionally determine whether or not a mixture of oligomeric forms of opsin exists and in what proportion. The application of this improved method revealed that opsin expressed in live Chinese hamster ovary (CHO) cells at 37°C exists as oligomers of various sizes. At lower concentrations, opsin existed in an equilibrium of dimers and tetramers. The tetramers were in the shape of a near-rhombus. At higher concentrations of the receptor, higher-order oligomers began to form. Thus, a mixture of different oligomeric forms of opsin is present in the membrane of live CHO cells and oligomerization occurs in a concentration-dependent manner. The general principles underlying the concentration-dependent oligomerization of opsin may be universal and apply to other GPCRs as well.
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