1
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Belkacemi K, Rondard P, Pin JP, Prézeau L. Heterodimers Revolutionize the Field of Metabotropic Glutamate Receptors. Neuroscience 2024:S0306-4522(24)00270-7. [PMID: 38936459 DOI: 10.1016/j.neuroscience.2024.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/29/2024]
Abstract
Identified 40 years ago, the metabotropic glutamate (mGlu) receptors play key roles in modulating many synapses in the brain, and are still considered as important drug targets to treat various brain diseases. Eight genes encoding mGlu subunits have been identified. They code for complex receptors composed of a large extracellular domain where glutamate binds, connected to a G protein activating membrane domain. They are covalently linked dimers, a quaternary structure needed for their activation by glutamate. For many years they have only been considered as homodimers, then limiting the number of mGlu receptors to 8 subtypes composed of twice the same subunit. Twelve years ago, mGlu subunits were shown to also form heterodimers with specific subunits combinations, increasing the family up to 19 different potential dimeric receptors. Since then, a number of studies brought evidence for the existence of such heterodimers in the brain, through various approaches. Structural and molecular dynamic studies helped understand their peculiar activation process. The present review summarizes the approaches used to study their activation process and their pharmacological properties and to demonstrate their existence in vivo. We will highlight how the existence of mGlu heterodimers revolutionizes the mGlu receptor field, opening new possibilities for therapeutic intervention for brain diseases. As illustrated by the number of possible mGlu heterodimers, this study will highlight the need for further research to fully understand their role in physiological and pathological conditions, and to develop more specific therapeutic tools.
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Affiliation(s)
- Kawthar Belkacemi
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, Inserm, Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, Inserm, Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, Inserm, Montpellier, France.
| | - Laurent Prézeau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, Inserm, Montpellier, France.
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2
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Eshak F, Pion L, Scholler P, Nevoltris D, Chames P, Rondard P, Pin JP, Acher FC, Goupil-Lamy A. Epitope Identification of an mGlu5 Receptor Nanobody Using Physics-Based Molecular Modeling and Deep Learning Techniques. J Chem Inf Model 2024; 64:4436-4461. [PMID: 38423996 DOI: 10.1021/acs.jcim.3c01620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The world has witnessed a revolution in therapeutics with the development of biological medicines such as antibodies and antibody fragments, notably nanobodies. These nanobodies possess unique characteristics including high specificity and modulatory activity, making them promising candidates for therapeutic applications. Identifying their binding mode is essential for their development. Experimental structural techniques are effective to get such information, but they are expensive and time-consuming. Here, we propose a computational approach, aiming to identify the epitope of a nanobody that acts as an agonist and a positive allosteric modulator at the rat metabotropic glutamate receptor 5. We employed multiple structure modeling tools, including various artificial intelligence algorithms for epitope mapping. The computationally identified epitope was experimentally validated, confirming the success of our approach. Additional dynamics studies provided further insights on the modulatory activity of the nanobody. The employed methodologies and approaches initiate a discussion on the efficacy of diverse techniques for epitope mapping and later nanobody engineering.
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Affiliation(s)
- Floriane Eshak
- SPPIN CNRS UMR 8003, Université Paris Cité, 75006 Paris, France
| | - Léo Pion
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, Inserm, 34094 Montpellier, France
| | - Pauline Scholler
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, Inserm, 34094 Montpellier, France
| | - Damien Nevoltris
- Aix Marseille University, CNRS, Inserm, Institut Paoli-Calmettes, CRCM, 13009 Marseille, France
| | - Patrick Chames
- Aix Marseille University, CNRS, Inserm, Institut Paoli-Calmettes, CRCM, 13009 Marseille, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, Inserm, 34094 Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, Inserm, 34094 Montpellier, France
| | | | - Anne Goupil-Lamy
- BIOVIA Science Council, Dassault Systèmes, 78140 Vélizy-Villacoublay, France
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3
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Zhu X, Luo M, An K, Shi D, Hou T, Warshel A, Bai C. Exploring the activation mechanism of metabotropic glutamate receptor 2. Proc Natl Acad Sci U S A 2024; 121:e2401079121. [PMID: 38739800 PMCID: PMC11126994 DOI: 10.1073/pnas.2401079121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Homomeric dimerization of metabotropic glutamate receptors (mGlus) is essential for the modulation of their functions and represents a promising avenue for the development of novel therapeutic approaches to address central nervous system diseases. Yet, the scarcity of detailed molecular and energetic data on mGlu2 impedes our in-depth comprehension of their activation process. Here, we employ computational simulation methods to elucidate the activation process and key events associated with the mGlu2, including a detailed analysis of its conformational transitions, the binding of agonists, Gi protein coupling, and the guanosine diphosphate (GDP) release. Our results demonstrate that the activation of mGlu2 is a stepwise process and several energy barriers need to be overcome. Moreover, we also identify the rate-determining step of the mGlu2's transition from the agonist-bound state to its active state. From the perspective of free-energy analysis, we find that the conformational dynamics of mGlu2's subunit follow coupled rather than discrete, independent actions. Asymmetric dimerization is critical for receptor activation. Our calculation results are consistent with the observation of cross-linking and fluorescent-labeled blot experiments, thus illustrating the reliability of our calculations. Besides, we also identify potential key residues in the Gi protein binding position on mGlu2, mGlu2 dimer's TM6-TM6 interface, and Gi α5 helix by the change of energy barriers after mutation. The implications of our findings could lead to a more comprehensive grasp of class C G protein-coupled receptor activation.
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Affiliation(s)
- Xiaohong Zhu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei230026, People's Republic of China
| | - Mengqi Luo
- College of Management, Shenzhen University, Shenzhen518060, People's Republic of China
| | - Ke An
- Chenzhu (MoMeD) Biotechnology Co., Ltd, Hangzhou, Zhejiang310005, People's Republic of China
| | - Danfeng Shi
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei230026, People's Republic of China
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou310058, People's Republic of China
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, CA90089-1062
| | - Chen Bai
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- Chenzhu (MoMeD) Biotechnology Co., Ltd, Hangzhou, Zhejiang310005, People's Republic of China
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4
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Krishna Kumar K, Wang H, Habrian C, Latorraca NR, Xu J, O'Brien ES, Zhang C, Montabana E, Koehl A, Marqusee S, Isacoff EY, Kobilka BK. Stepwise activation of a metabotropic glutamate receptor. Nature 2024; 629:951-956. [PMID: 38632403 DOI: 10.1038/s41586-024-07327-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/15/2024] [Indexed: 04/19/2024]
Abstract
Metabotropic glutamate receptors belong to a family of G protein-coupled receptors that are obligate dimers and possess a large extracellular ligand-binding domain that is linked via a cysteine-rich domain to their 7-transmembrane domain1. Upon activation, these receptors undergo a large conformational change to transmit the ligand binding signal from the extracellular ligand-binding domain to the G protein-coupling 7-transmembrane domain2. In this manuscript, we propose a model for a sequential, multistep activation mechanism of metabotropic glutamate receptor subtype 5. We present a series of structures in lipid nanodiscs, from inactive to fully active, including agonist-bound intermediate states. Further, using bulk and single-molecule fluorescence imaging, we reveal distinct receptor conformations upon allosteric modulator and G protein binding.
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Affiliation(s)
- Kaavya Krishna Kumar
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA, USA
| | - Chris Habrian
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Naomi R Latorraca
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Jun Xu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Evan S O'Brien
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Chensong Zhang
- Division of CryoEM and Bioimaging, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Elizabeth Montabana
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Antoine Koehl
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Susan Marqusee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- QB3 Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
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5
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McCullock TW, Cardani LP, Kammermeier PJ. Signaling Specificity and Kinetics of the Human Metabotropic Glutamate Receptors. Mol Pharmacol 2024; 105:104-115. [PMID: 38164584 PMCID: PMC10794986 DOI: 10.1124/molpharm.123.000795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/13/2023] [Accepted: 11/08/2023] [Indexed: 01/03/2024] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a bioluminescence resonance energy transfer-based assay that detects the interaction between a split YFP-tagged Gβ 1γ2 and a Nanoluciferase tagged free Gβγ sensor, MAS-GRK3-ct- nanoluciferase with 14 specific Gα proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2 and 3 and 4, 6, 7, and 8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1 and 5) are known to couple to the Gq/11 family and generally thought to also couple to the pertussis toxin-sensitive Gi/o family some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all eight mGluRs through the Gi/o proteins and only mGluR1 and mGluR5 through Gq/11, and, perhaps surprisingly, not G14 None activated any Gs protein. Interestingly, coupling was seen with the group I and II but not the group III mGluRs to G16 Slow but significant coupling to Gz was also seen with the group II receptors. SIGNIFICANCE STATEMENT: Metabotropic glutamate receptor (mGluR)-G protein coupling has not been thoroughly examined, and some controversy remains about whether some mGluRs can activate Gαs family members. Here we examine the ability of each mGluR to activate representative members of every Gα protein family. While all mGluRs can activate Gαi/o proteins, only the group I mGluRs couple to Gαq/11, and no members of the family can activate Gαs family members, including the group I receptors alone or with positive allosteric modulators.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Loren P Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
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6
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Benndorf K, Schulz E. Identifiability of equilibrium constants for receptors with two to five binding sites. J Gen Physiol 2023; 155:e202313423. [PMID: 37882789 PMCID: PMC10602793 DOI: 10.1085/jgp.202313423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/22/2023] [Accepted: 10/07/2023] [Indexed: 10/27/2023] Open
Abstract
Ligand-gated ion channels (LGICs) are regularly oligomers containing between two and five binding sites for ligands. Neither in homomeric nor heteromeric LGICs the activation process evoked by the ligand binding is fully understood. Here, we show on theoretical grounds that for LGICs with two to five binding sites, the cooperativity upon channel activation can be determined in considerable detail. The main requirements for our strategy are a defined number of binding sites in a channel, which can be achieved by concatenation, a systematic mutation of all binding sites and a global fit of all concentration-activation relationships (CARs) with corresponding intimately coupled Markovian state models. We take advantage of translating these state models to cubes with dimensions 2, 3, 4, and 5. We show that the maximum possible number of CARs for these LGICs specify all 7, 13, 23, and 41 independent model parameters, respectively, which directly provide all equilibrium constants within the respective schemes. Moreover, a fit that uses stochastically varied scaled unitary start vectors enables the determination of all parameters, without any bias imposed by specific start vectors. A comparison of the outcome of the analyses for the models with 2 to 5 binding sites showed that the identifiability of the parameters is best for a case with 5 binding sites and 41 parameters. Our strategy can be used to analyze experimental data of other LGICs and may be applicable to voltage-gated ion channels and metabotropic receptors.
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Affiliation(s)
- Klaus Benndorf
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eckhard Schulz
- Faculty of Electrical Engineering, Schmalkalden University of Applied Sciences, Schmalkalden, Germany
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7
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Kumar KK, Wang H, Habrian C, Latorraca NR, Xu J, O’Brien ES, Zhang C, Montabana E, Koehl A, Marqusee S, Isacoff EY, Kobilka BK. Step-wise activation of a Family C GPCR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555158. [PMID: 37693614 PMCID: PMC10491200 DOI: 10.1101/2023.08.29.555158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Metabotropic glutamate receptors belong to a family of G protein-coupled receptors that are obligate dimers and possess a large extracellular ligand-binding domain (ECD) that is linked via a cysteine-rich domain (CRDs) to their 7-transmembrane (TM) domain. Upon activation, these receptors undergo a large conformational change to transmit the ligand binding signal from the ECD to the G protein-coupling TM. In this manuscript, we propose a model for a sequential, multistep activation mechanism of metabotropic glutamate receptor subtype 5. We present a series of structures in lipid nanodiscs, from inactive to fully active, including agonist-bound intermediate states. Further, using bulk and single-molecule fluorescence imaging we reveal distinct receptor conformations upon allosteric modulator and G protein binding.
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Affiliation(s)
- Kaavya Krishna Kumar
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
- Sarafin ChEM-H, 290 Jane Stanford Way, Stanford, California 94305, USA
| | - Chris Habrian
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
| | - Naomi R. Latorraca
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA
| | - Jun Xu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
| | - Evan S. O’Brien
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
| | - Chensong Zhang
- Division of CryoEM and Bioimaging, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Elizabeth Montabana
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
| | - Antoine Koehl
- Department of Statistics, University of California, Berkeley, CA 94720, USA
| | - Susan Marqusee
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA; QB3 Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley CA 94720, USA; Department of Chemistry, University of California, Berkeley, Berkeley CA 94720, USA
| | - Ehud Y. Isacoff
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley CA 94720, USA
| | - Brian K. Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA
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8
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McCullock TW, Cardani LP, Kammermeier PJ. Signaling specificity and kinetics of the human metabotropic glutamate receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550373. [PMID: 37546908 PMCID: PMC10402105 DOI: 10.1101/2023.07.24.550373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a BRET based assay that detects the interaction between a split YFP-tagged Gβ1γ2 and a Nanoluc tagged free Gβγ sensor, MAS-GRK3-ct-NLuc with 14 specific Ga proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2&3, and 4, 6, 7&8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1&5) are known to couple to the Gq/11 family, and generally thought to also couple to the PTX-sensitive Gi/o family; some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all 8 mGluRs through the Gi/o proteins, and only mGluR1&5 through Gq/11, and perhaps surprisingly, not G14. None activated any Gs protein. Interestingly, coupling was seen with the group I and II, but not the group III mGluRs to G16. Slow but significant coupling to Gz was also seen with the group II receptors.
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Affiliation(s)
- Tyler W. McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Loren P. Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Paul J. Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
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9
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Liu L, Lin L, Shen C, Rondard P, Pin JP, Xu C, Liu J. Asymmetric activation of dimeric GABA B and metabotropic glutamate receptors. Am J Physiol Cell Physiol 2023; 325:C79-C89. [PMID: 37184233 DOI: 10.1152/ajpcell.00150.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/27/2023] [Accepted: 05/11/2023] [Indexed: 05/16/2023]
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of membrane proteins and are important drug targets. GPCRs are allosteric machines that transduce an extracellular signal to the cell by activating heterotrimeric G proteins. Herein, we summarize the recent advancements in the molecular activation mechanism of the γ-aminobutyric acid type B (GABAB) and metabotropic glutamate (mGlu) receptors, the most important class C GPCRs that modulate synaptic transmission in the brain. Both are mandatory dimers, this quaternary structure being needed for their function The structures of these receptors in different conformations and in complexes with G proteins have revealed their asymmetric activation. This asymmetry is further highlighted by the recent discovery of mGlu heterodimers, where the eight mGlu subunits can form specific and functional heterodimers. Finally, the development of allosteric modulators has revealed new possibilities for regulating the function of these receptors by targeting the transmembrane dimer interface. This family of receptors never ceases to astonish and serve as models to better understand the diversity and asymmetric functioning of GPCRs.NEW & NOTEWORTHY γ-aminobutyric acid type B (GABAB) and metabotropic glutamate (mGlu) receptors form constitutive dimers, which are required for their function. They serve as models to better understand the diversity and activation of G protein-coupled receptors (GPCRs). The structures of these receptors in different conformations and in complexes with G proteins have revealed their asymmetric activation. This asymmetry is further highlighted by the recent discovery of specific and functional mGlu heterodimers. Allosteric modulators can be developed to target the transmembrane interface and modulate the asymmetry.
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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, People's Republic of China
| | - Li Lin
- 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, People's Republic of China
| | - Cangsong Shen
- 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, People's Republic of China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Chanjuan Xu
- 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, People's Republic of China
| | - 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, People's Republic of China
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10
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Lei X, Hofmann CS, Rodriguez AL, Niswender CM. Differential Activity of Orthosteric Agonists and Allosteric Modulators at Metabotropic Glutamate Receptor 7. Mol Pharmacol 2023; 104:17-27. [PMID: 37105671 PMCID: PMC10289241 DOI: 10.1124/molpharm.123.000678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/29/2023] Open
Abstract
Metabotropic glutamate receptor 7 (mGlu7) is a G protein coupled receptor that has demonstrated promise as a therapeutic target across a number of neurologic and psychiatric diseases. Compounds that modulate the activity of mGlu7, such as positive and negative allosteric modulators, may represent new therapeutic strategies to modulate receptor activity. The endogenous neurotransmitter associated with the mGlu receptor family, glutamate, exhibits low efficacy and potency in activating mGlu7, and surrogate agonists, such as the compound L-(+)-2-Amino-4-phosphonobutyric acid (L-AP4), are often used for receptor activation and compound profiling. To understand the implications of the use of such agonists in the development of positive allosteric modulators (PAMs), we performed a systematic evaluation of receptor activation using a system in which mutations can be made in either protomer of the mGlu7 dimer; we employed mutations that prevent interaction with the orthosteric site as well as the G-protein coupling site of the receptor. We then measured increases in calcium levels downstream of a promiscuous G protein to assess the effects of mutations in one of the two protomers in the presence of two different agonists and three positive allosteric modulators. Our results reveal that distinct PAMs, for example N-[3-Chloro-4-[(5-chloro-2-pyridinyl)oxy]phenyl]-2-pyridinecarboxamide (VU0422288) and 3-(2,3-Difluoro-4-methoxyphenyl)-2,5-dimethyl-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine (VU6005649), do exhibit different maximal levels of potentiation with L-AP4 versus glutamate, but there appear to be common stable receptor conformations that are shared among all of the compounds examined here. SIGNIFICANCE STATEMENT: This manuscript describes the systematic evaluation of the mGlu7 agonists glutamate and L-(+)-2-Amino-4-phosphonobutyric acid (L-AP4) in the presence and absence of three distinct potentiators examining possible mechanistic differences. These findings demonstrate that mGlu7 potentiators display subtle variances in response to glutamate versus L-AP4.
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Affiliation(s)
- Xia Lei
- Department of Pharmacology (X.L., C.S.H., A.L.R., C.M.N.), Warren Center for Neuroscience Drug Discovery (X.L., A.L.R., C.M.N.), Vanderbilt Institute of Chemical Biology (C.M.N.), and Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennesee (C.M.N.); and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
| | - Christopher S Hofmann
- Department of Pharmacology (X.L., C.S.H., A.L.R., C.M.N.), Warren Center for Neuroscience Drug Discovery (X.L., A.L.R., C.M.N.), Vanderbilt Institute of Chemical Biology (C.M.N.), and Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennesee (C.M.N.); and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
| | - Alice L Rodriguez
- Department of Pharmacology (X.L., C.S.H., A.L.R., C.M.N.), Warren Center for Neuroscience Drug Discovery (X.L., A.L.R., C.M.N.), Vanderbilt Institute of Chemical Biology (C.M.N.), and Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennesee (C.M.N.); and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
| | - Colleen M Niswender
- Department of Pharmacology (X.L., C.S.H., A.L.R., C.M.N.), Warren Center for Neuroscience Drug Discovery (X.L., A.L.R., C.M.N.), Vanderbilt Institute of Chemical Biology (C.M.N.), and Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennesee (C.M.N.); and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
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11
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Saha S, González-Maeso J. The crosstalk between 5-HT 2AR and mGluR2 in schizophrenia. Neuropharmacology 2023; 230:109489. [PMID: 36889432 PMCID: PMC10103009 DOI: 10.1016/j.neuropharm.2023.109489] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/26/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Schizophrenia is a severe brain disorder that usually produces a lifetime of disability. First generation or typical antipsychotics such as haloperidol and second generation or atypical antipsychotics such as clozapine and risperidone remain the current standard for schizophrenia treatment. In some patients with schizophrenia, antipsychotics produce complete remission of positive symptoms, such as hallucinations and delusions. However, antipsychotic drugs are ineffective against cognitive deficits and indeed treated schizophrenia patients have small improvements or even deterioration in several cognitive domains. This underlines the need for novel and more efficient therapeutic targets for schizophrenia treatment. Serotonin and glutamate have been identified as key parts of two neurotransmitter systems involved in fundamental brain processes. Serotonin (or 5-hydroxytryptamine) 5-HT2A receptor (5-HT2AR) and metabotropic glutamate 2 receptor (mGluR2) are G protein-coupled receptors (GPCRs) that interact at epigenetic and functional levels. These two receptors can form GPCR heteromeric complexes through which their pharmacology, function and trafficking becomes affected. Here we review past and current research on the 5-HT2AR-mGluR2 heterocomplex and its potential implication in schizophrenia and antipsychotic drug action. This article is part of the Special Issue on "The receptor-receptor interaction as a new target for therapy".
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Affiliation(s)
- Somdatta Saha
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
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12
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Freitas GA, Niswender CM. GRM7 gene mutations and consequences for neurodevelopment. Pharmacol Biochem Behav 2023; 225:173546. [PMID: 37003303 PMCID: PMC10192299 DOI: 10.1016/j.pbb.2023.173546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The metabotropic glutamate receptor 7 (mGlu7), encoded by the GRM7 gene in humans, is a presynaptic, G protein-coupled glutamate receptor that is essential for modulating neurotransmission. Mutations in or reduced expression of GRM7 have been identified in different genetic neurodevelopmental disorders (NDDs), and rare biallelic missense variants have been proposed to underlie a subset of NDDs. Clinical GRM7 variants have been associated with a range of symptoms consistent with neurodevelopmental molecular features, including hypomyelination, brain atrophy and defects in axon outgrowth. Here, we review the newest findings regarding the cellular and molecular defects caused by GRM7 variants in NDD patients.
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Affiliation(s)
- Geanne A Freitas
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America.
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13
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Liu H, Li Y, Gao Y. Asymmetric activation of class C GPCRs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 195:77-87. [PMID: 36707156 DOI: 10.1016/bs.pmbts.2022.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Class C G-protein-coupled receptors (GPCRs) comprise a unique GPCR subfamily with large ligand-binding extracellular domains and function as obligate dimers. The recently resolved cryo-EM structures of full-length GABAB, CaSR, and mGlus have revealed that these receptors are activated in an asymmetric manner, leading to G-protein-coupling on one protomer within the receptor dimer. In this review we discuss the mechanisms of asymmetric activation in class C GPCRs and the unique mode of interaction with the inhibitory Gi protein. Upon activation, the two seven-transmembrane domains (7TMs) of class C GPCRs rearrange to form a conserved asymmetric TM6-TM6 interface. In contrast to class A and B GPCRs, G-protein coupling does not involve the cytoplasmic opening of TM6, but is facilitated through the coordination of intracellular loops. Furthermore, positive and negative allosteric modulators (PAMs and NAMs) adopt distinct conformations to regulate the activity of class C GPCRs. Taken together, these recent findings on the mechanism of asymmetric activation of class C GPCRs highlight a novel mechanism of G protein activation and provide new insights into the design of therapeutics targeting these receptors.
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Affiliation(s)
- Hongnan Liu
- Department of Cardiology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Yanjun Li
- Department of Cardiology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Yang Gao
- Department of Cardiology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China; Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Hangzhou, China.
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14
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Gorvin CM. Recent advances in calcium-sensing receptor structures and signaling pathways. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 195:121-135. [PMID: 36707151 DOI: 10.1016/bs.pmbts.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The calcium-sensing receptor (CaSR) is a class C GPCR that has a fundamental role in extracellular calcium homeostasis by regulating parathyroid hormone release and urinary calcium excretion. Germline mutations in the receptor cause disorders of calcium homeostasis and studies of the functional effects of these mutations has facilitated understanding of CaSR signaling and how allosteric modulators affect these responses. In the past year, five cryo-EM structures of the near full-length CaSR have been published, demonstrating how agonist-binding transmits changes in the CaSR extracellular domain to the transmembrane region to activate G proteins, and how allosteric modulators affect these structural dynamics. Additionally, several recent studies have identified CaSR interacting proteins that regulate CaSR signaling and trafficking and contribute to understanding how the receptor achieves rapid and diverse physiological responses.
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Affiliation(s)
- Caroline M Gorvin
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, United Kingdom; Institute of Metabolism and Systems Research (IMSR) and Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, United Kingdom.
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15
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An K, Zhu X, Bai C. The Nature of Functional Features of Different Classes of G-Protein-Coupled Receptors. BIOLOGY 2022; 11:1839. [PMID: 36552350 PMCID: PMC9775959 DOI: 10.3390/biology11121839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
G-protein-coupled receptors (GPCRs) are a critical family in the human proteome and are involved in various physiological processes. They are also the most important drug target, with approximately 30% of approved drugs acting on such receptors. The members of the family are divided into six classes based on their structural and functional characteristics. Understanding their structural-functional relationships will benefit us in future drug development. In this article, we investigate the features of protein function, structure, and energy that describe the dynamics of the GPCR activation process between different families. GPCRs straddle the cell membrane and transduce signals from outside the membrane into the cell. During the process, the conformational change in GPCRs that is activated by the binding of signal molecules is essential. During the binding process, different types of signal molecules result in different signal transfer efficiencies. Therefore, the GPCR classes show a variety of structures and activation processes. Based on the experimental crystal structures, we modeled the activation process of the β2 adrenergic receptor (β2AR), glucagon receptor (GCGR), and metabotropic glutamate receptor 2 (mGluR2), which represent class A, B, and C GPCRs, respectively. We calculated their activation free-energy landscapes and analyzed the structure-energy-function relationship. The results show a consistent picture of the activation mechanisms between different types of GPCRs. This could also provide us a way to understand other signal transduction proteins.
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Affiliation(s)
- Ke An
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Xiaohong Zhu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Chen Bai
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, China
- Chenzhu (MoMeD) Biotechnology Co., Ltd., Hangzhou 310005, China
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16
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Jakubík J, Randáková A. Insights into the operational model of agonism of receptor dimers. Expert Opin Drug Discov 2022; 17:1181-1191. [PMID: 36369915 DOI: 10.1080/17460441.2023.2147502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 11/10/2022] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Accurate ranking of efficacies and potencies of agonists is essential in the discovery of new selective agonists. For the purpose of system-independent ranking of agonists, the operational model of agonism (OMA) has become a standard. Many receptors function as oligomers which makes functional responses more complex, requiring an extension of the original OMA. AREAS COVERED Explicit equations of the operational model of agonism of receptor dimers (OMARD) were derived. The OMARD can be applied to any receptor possessing two orthosteric sites. The behavior of OMARD was analyzed to demonstrate its complexity and relation to experimental data. Properties of OMARD and OMA equations were compared to demonstrate their pros and cons. EXPERT OPINION Extension of OMA by slope factors gives simple equations of functional response that are easy to fit experimental data but results may be inaccurate because of exponentiation of operational efficacy. Also, such equations cannot accommodate bell-shaped curves. Explicit equations of OMARD give accurate results but are complex and tedious to fit experimental data. All operational models use inter-dependent parameters that are a hurdle in the fitting. A good understanding of OMARD behavior helps to overcome such obstacles.
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Affiliation(s)
- Jan Jakubík
- Laboratory of Neurochemistry, Institute of Physiology CAS, Prague, Czech Republic
| | - Alena Randáková
- Laboratory of Neurochemistry, Institute of Physiology CAS, Prague, Czech Republic
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17
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Liu J, Tang H, Xu C, Zhou S, Zhu X, Li Y, Prézeau L, Xu T, Pin JP, Rondard P, Ji W, Liu J. Biased signaling due to oligomerization of the G protein-coupled platelet-activating factor receptor. Nat Commun 2022; 13:6365. [PMID: 36289206 PMCID: PMC9606269 DOI: 10.1038/s41467-022-34056-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/11/2022] [Indexed: 12/25/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are important drug targets that mediate various signaling pathways by activating G proteins and engaging β-arrestin proteins. Despite its importance for the development of therapeutics with fewer side effects, the underlying mechanism that controls the balance between these signaling modes of GPCRs remains largely unclear. Here, we show that assembly into dimers and oligomers can largely influence the signaling mode of the platelet-activating factor receptor (PAFR). Single-particle analysis results show that PAFR can form oligomers at low densities through two possible dimer interfaces. Stabilization of PAFR oligomers through cross-linking increases G protein activity, and decreases β-arrestin recruitment and agonist-induced internalization significantly. Reciprocally, β-arrestin prevents PAFR oligomerization. Our results highlight a mechanism involved in the control of receptor signaling, and thereby provide important insights into the relationship between GPCR oligomerization and downstream signaling.
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Affiliation(s)
- Junke Liu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China ,grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Hengmin Tang
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Chanjuan Xu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Shengnan Zhou
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Xunying Zhu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Yuanyuan Li
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Laurent Prézeau
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Tao Xu
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
| | - Jean-Philippe Pin
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Philippe Rondard
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Wei Ji
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
| | - Jianfeng Liu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
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18
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McCullock TW, Kammermeier PJ. The evidence for and consequences of metabotropic glutamate receptor heterodimerization. Neuropharmacology 2021; 199:108801. [PMID: 34547332 DOI: 10.1016/j.neuropharm.2021.108801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 09/07/2021] [Accepted: 09/17/2021] [Indexed: 12/15/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are an essential component of the mammalian central nervous system. These receptors modulate neuronal excitability in response to extracellular glutamate through the activation of intracellular heterotrimeric G proteins. Like most other class C G protein-coupled receptors, mGluRs function as obligate dimer proteins, meaning they need to form dimer complexes before becoming functional receptors. All mGluRs possess the ability to homodimerize, but studies over the past ten years have demonstrated these receptors are also capable of forming heterodimers in specific patterns. These mGluR heterodimers appear to have their own unique biophysical behavior and pharmacology with both native and synthetic compounds with few rules having been identified that allow for prediction of the consequences of any particular mGluR pair forming heterodimers. Here, we review the relevant literature demonstrating the existence and consequences of mGluR heterodimerization. By collecting biophysical and pharmacological data of several mGluR heterodimers we demonstrate the lack of generalizable behavior of these complexes indicating that each individual dimeric pair needs to be investigated independently. Additionally, by combining sequence alignment and structural analysis, we propose that interactions between the β4-A Helix Loop and the D Helix in the extracellular domain of these receptors are the structural components that dictate heterodimerization compatibility. Finally, we discuss the potential implications of mGluR heterodimerization from the viewpoints of further developing our understanding of neuronal physiology and leveraging mGluRs as a therapeutic target for the treatment of pathophysiology.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
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19
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El Khamlichi C, Cobret L, Arrang JM, Morisset-Lopez S. BRET Analysis of GPCR Dimers in Neurons and Non-Neuronal Cells: Evidence for Inactive, Agonist, and Constitutive Conformations. Int J Mol Sci 2021; 22:ijms221910638. [PMID: 34638980 PMCID: PMC8508734 DOI: 10.3390/ijms221910638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 11/29/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are dimeric proteins, but the functional consequences of the process are still debated. Active GPCR conformations are promoted either by agonists or constitutive activity. Inverse agonists decrease constitutive activity by promoting inactive conformations. The histamine H3 receptor (H3R) is the target of choice for the study of GPCRs because it displays high constitutive activity. Here, we study the dimerization of recombinant and brain H3R and explore the effects of H3R ligands of different intrinsic efficacy on dimerization. Co-immunoprecipitations and Western blots showed that H3R dimers co-exist with monomers in transfected HEK 293 cells and in rodent brains. Bioluminescence energy transfer (BRET) analysis confirmed the existence of spontaneous H3R dimers, not only in living HEK 293 cells but also in transfected cortical neurons. In both cells, agonists and constitutive activity of the H3R decreased BRET signals, whereas inverse agonists and GTPγS, which promote inactive conformations, increased BRET signals. These findings show the existence of spontaneous H3R dimers not only in heterologous systems but also in native tissues, which are able to adopt a number of allosteric conformations, from more inactive to more active states.
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Affiliation(s)
- Chayma El Khamlichi
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Université d’Orléans, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France; (C.E.K.); (L.C.)
| | - Laetitia Cobret
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Université d’Orléans, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France; (C.E.K.); (L.C.)
| | - Jean-Michel Arrang
- Centre de Psychiatrie et Neurosciences, 2 ter Rue d’Alésia, 75014 Paris, France;
- Institut de Psychiatrie et Neurosciences de Paris, UMR_S1266 INSERM, Université Paris Descartes, 102 Rue de la Santé, 75014 Paris, France
| | - Séverine Morisset-Lopez
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Université d’Orléans, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France; (C.E.K.); (L.C.)
- Institut de Psychiatrie et Neurosciences de Paris, UMR_S1266 INSERM, Université Paris Descartes, 102 Rue de la Santé, 75014 Paris, France
- Correspondence: ; Tel.: +33-238257858
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20
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Xiao H, Sun Q. Cyro-EM structure of human mGlus: leading therapeutic potential to neurological diseases. Signal Transduct Target Ther 2021; 6:302. [PMID: 34400607 PMCID: PMC8367988 DOI: 10.1038/s41392-021-00720-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 07/16/2021] [Indexed: 02/08/2023] Open
Affiliation(s)
- Huan Xiao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Qiu Sun
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China.
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21
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22
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Seven AB, Barros-Álvarez X, de Lapeyrière M, Papasergi-Scott MM, Robertson MJ, Zhang C, Nwokonko RM, Gao Y, Meyerowitz JG, Rocher JP, Schelshorn D, Kobilka BK, Mathiesen JM, Skiniotis G. G-protein activation by a metabotropic glutamate receptor. Nature 2021; 595:450-454. [PMID: 34194039 DOI: 10.1038/s41586-021-03680-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/01/2021] [Indexed: 01/14/2023]
Abstract
Family C G-protein-coupled receptors (GPCRs) operate as obligate dimers with extracellular domains that recognize small ligands, leading to G-protein activation on the transmembrane (TM) domains of these receptors by an unknown mechanism1. Here we show structures of homodimers of the family C metabotropic glutamate receptor 2 (mGlu2) in distinct functional states and in complex with heterotrimeric Gi. Upon activation of the extracellular domain, the two transmembrane domains undergo extensive rearrangement in relative orientation to establish an asymmetric TM6-TM6 interface that promotes conformational changes in the cytoplasmic domain of one protomer. Nucleotide-bound Gi can be observed pre-coupled to inactive mGlu2, but its transition to the nucleotide-free form seems to depend on establishing the active-state TM6-TM6 interface. In contrast to family A and B GPCRs, G-protein coupling does not involve the cytoplasmic opening of TM6 but is facilitated through the coordination of intracellular loops 2 and 3, as well as a critical contribution from the C terminus of the receptor. The findings highlight the synergy of global and local conformational transitions to facilitate a new mode of G-protein activation.
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Affiliation(s)
- Alpay B Seven
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ximena Barros-Álvarez
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Makaía M Papasergi-Scott
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael J Robertson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Chensong Zhang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Robert M Nwokonko
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Yang Gao
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Justin G Meyerowitz
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | | | | | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
| | - Jesper M Mathiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
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23
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Asymmetric activation of the calcium-sensing receptor homodimer. Nature 2021; 595:455-459. [PMID: 34194040 DOI: 10.1038/s41586-021-03691-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/03/2021] [Indexed: 12/21/2022]
Abstract
The calcium-sensing receptor (CaSR), a cell-surface sensor for Ca2+, is the master regulator of calcium homeostasis in humans and is the target of calcimimetic drugs for the treatment of parathyroid disorders1. CaSR is a family C G-protein-coupled receptor2 that functions as an obligate homodimer, with each protomer composed of a Ca2+-binding extracellular domain and a seven-transmembrane-helix domain (7TM) that activates heterotrimeric G proteins. Here we present cryo-electron microscopy structures of near-full-length human CaSR in inactive or active states bound to Ca2+ and various calcilytic or calcimimetic drug molecules. We show that, upon activation, the CaSR homodimer adopts an asymmetric 7TM configuration that primes one protomer for G-protein coupling. This asymmetry is stabilized by 7TM-targeting calcimimetic drugs adopting distinctly different poses in the two protomers, whereas the binding of a calcilytic drug locks CaSR 7TMs in an inactive symmetric configuration. These results provide a detailed structural framework for CaSR activation and the rational design of therapeutics targeting this receptor.
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24
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Lin S, Han S, Cai X, Tan Q, Zhou K, Wang D, Wang X, Du J, Yi C, Chu X, Dai A, Zhou Y, Chen Y, Zhou Y, Liu H, Liu J, Yang D, Wang MW, Zhao Q, Wu B. Structures of G i-bound metabotropic glutamate receptors mGlu2 and mGlu4. Nature 2021; 594:583-588. [PMID: 34135510 DOI: 10.1038/s41586-021-03495-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/25/2021] [Indexed: 01/15/2023]
Abstract
The metabotropic glutamate receptors (mGlus) have key roles in modulating cell excitability and synaptic transmission in response to glutamate (the main excitatory neurotransmitter in the central nervous system)1. It has previously been suggested that only one receptor subunit within an mGlu homodimer is responsible for coupling to G protein during receptor activation2. However, the molecular mechanism that underlies the asymmetric signalling of mGlus remains unknown. Here we report two cryo-electron microscopy structures of human mGlu2 and mGlu4 bound to heterotrimeric Gi protein. The structures reveal a G-protein-binding site formed by three intracellular loops and helices III and IV that is distinct from the corresponding binding site in all of the other G-protein-coupled receptor (GPCR) structures. Furthermore, we observed an asymmetric dimer interface of the transmembrane domain of the receptor in the two mGlu-Gi structures. We confirmed that the asymmetric dimerization is crucial for receptor activation, which was supported by functional data; this dimerization may provide a molecular basis for the asymmetric signal transduction of mGlus. These findings offer insights into receptor signalling of class C GPCRs.
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Affiliation(s)
- Shuling Lin
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuo Han
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoqing Cai
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qiuxiang Tan
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kexiu Zhou
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Dejian Wang
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xinwei Wang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Juan Du
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Cuiying Yi
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaojing Chu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Antao Dai
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yan Zhou
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yan Chen
- School of Pharmacy, Fudan University, Shanghai, China
| | - Yu Zhou
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Hong Liu
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jianfeng Liu
- Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Dehua Yang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ming-Wei Wang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. .,University of Chinese Academy of Sciences, Beijing, China. .,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, China. .,School of Pharmacy, Fudan University, Shanghai, China. .,School of Basic Medical Sciences, Fudan University, Shanghai, China.
| | - Qiang Zhao
- University of Chinese Academy of Sciences, Beijing, China. .,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. .,Zhongshan Branch, Institute of Drug Discovery and Development, Chinese Academy of Sciences, Zhongshan, China.
| | - Beili Wu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. .,University of Chinese Academy of Sciences, Beijing, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, China. .,School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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25
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Structural Characterization of Receptor-Receptor Interactions in the Allosteric Modulation of G Protein-Coupled Receptor (GPCR) Dimers. Int J Mol Sci 2021; 22:ijms22063241. [PMID: 33810175 PMCID: PMC8005122 DOI: 10.3390/ijms22063241] [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: 02/26/2021] [Revised: 03/17/2021] [Accepted: 03/20/2021] [Indexed: 01/07/2023] Open
Abstract
G protein-coupled receptor (GPCR) oligomerization, while contentious, continues to attract the attention of researchers. Numerous experimental investigations have validated the presence of GPCR dimers, and the relevance of dimerization in the effectuation of physiological functions intensifies the attractiveness of this concept as a potential therapeutic target. GPCRs, as a single entity, have been the main source of scrutiny for drug design objectives for multiple diseases such as cancer, inflammation, cardiac, and respiratory diseases. The existence of dimers broadens the research scope of GPCR functions, revealing new signaling pathways that can be targeted for disease pathogenesis that have not previously been reported when GPCRs were only viewed in their monomeric form. This review will highlight several aspects of GPCR dimerization, which include a summary of the structural elucidation of the allosteric modulation of class C GPCR activation offered through recent solutions to the three-dimensional, full-length structures of metabotropic glutamate receptor and γ-aminobutyric acid B receptor as well as the role of dimerization in the modification of GPCR function and allostery. With the growing influence of computational methods in the study of GPCRs, we will also be reviewing recent computational tools that have been utilized to map protein-protein interactions (PPI).
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26
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Gregory KJ, Goudet C. International Union of Basic and Clinical Pharmacology. CXI. Pharmacology, Signaling, and Physiology of Metabotropic Glutamate Receptors. Pharmacol Rev 2020; 73:521-569. [PMID: 33361406 DOI: 10.1124/pr.119.019133] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors respond to glutamate, the major excitatory neurotransmitter in the mammalian brain, mediating a modulatory role that is critical for higher-order brain functions such as learning and memory. Since the first mGlu receptor was cloned in 1992, eight subtypes have been identified along with many isoforms and splice variants. The mGlu receptors are transmembrane-spanning proteins belonging to the class C G protein-coupled receptor family and represent attractive targets for a multitude of central nervous system disorders. Concerted drug discovery efforts over the past three decades have yielded a wealth of pharmacological tools including subtype-selective agents that competitively block or mimic the actions of glutamate or act allosterically via distinct sites to enhance or inhibit receptor activity. Herein, we review the physiologic and pathophysiological roles for individual mGlu receptor subtypes including the pleiotropic nature of intracellular signal transduction arising from each. We provide a comprehensive analysis of the in vitro and in vivo pharmacological properties of prototypical and commercially available orthosteric agonists and antagonists as well as allosteric modulators, including ligands that have entered clinical trials. Finally, we highlight emerging areas of research that hold promise to facilitate rational design of highly selective mGlu receptor-targeting therapeutics in the future. SIGNIFICANCE STATEMENT: The metabotropic glutamate receptors are attractive therapeutic targets for a range of psychiatric and neurological disorders. Over the past three decades, intense discovery efforts have yielded diverse pharmacological tools acting either competitively or allosterically, which have enabled dissection of fundamental biological process modulated by metabotropic glutamate receptors and established proof of concept for many therapeutic indications. We review metabotropic glutamate receptor molecular pharmacology and highlight emerging areas that are offering new avenues to selectively modulate neurotransmission.
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Affiliation(s)
- Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
| | - Cyril Goudet
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
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27
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Werthmann RC, Tzouros M, Lamerz J, Augustin A, Fritzius T, Trovò L, Stawarski M, Raveh A, Diener C, Fischer C, Gassmann M, Lindemann L, Bettler B. Symmetric signal transduction and negative allosteric modulation of heterodimeric mGlu1/5 receptors. Neuropharmacology 2020; 190:108426. [PMID: 33279506 DOI: 10.1016/j.neuropharm.2020.108426] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 11/09/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
For a long time metabotropic glutamate receptors (mGluRs) were thought to regulate neuronal functions as obligatory homodimers. Recent reports, however, indicate the existence of heterodimers between group-II and -III mGluRs in the brain, which differ from the homodimers in their signal transduction and sensitivity to negative allosteric modulators (NAMs). Whether the group-I mGluRs, mGlu1 and mGlu5, form functional heterodimers in the brain is still a matter of debate. We now show that mGlu1 and mGlu5 co-purify from brain membranes and hippocampal tissue and co-localize in cultured hippocampal neurons. Complementation assays with mutants deficient in agonist-binding or G protein-coupling reveal that mGlu1/5 heterodimers are functional in heterologous cells and transfected cultured hippocampal neurons. In contrast to heterodimers between group-II and -III mGluRs, mGlu1/5 receptors exhibit a symmetric signal transduction, with both protomers activating G proteins to a similar extent. NAMs of either protomer in mGlu1/5 receptors partially inhibit signaling, showing that both protomers need to be able to reach an active conformation for full receptor activity. Complete heterodimer inhibition is observed when both protomers are locked in their inactive state by a NAM. In summary, our data show that mGlu1/5 heterodimers exhibit a symmetric signal transduction and thus intermediate signaling efficacy and kinetic properties. Our data support the existence of mGlu1/5 heterodimers in neurons and highlight differences in the signaling transduction of heterodimeric mGluRs that influence allosteric modulation.
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Affiliation(s)
- Ruth C Werthmann
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Manuel Tzouros
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Jens Lamerz
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Angélique Augustin
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Thorsten Fritzius
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Luca Trovò
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Michal Stawarski
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Adi Raveh
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Catherine Diener
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Christophe Fischer
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Martin Gassmann
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Lothar Lindemann
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience and Rare Diseases (NRD) (LL, CD, CF), Pharmaceutical Sciences, Biomarkers, Bioinformatics and Omics & Pathology (MT, JL, AA), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
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28
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Ellaithy A, Gonzalez-Maeso J, Logothetis DA, Levitz J. Structural and Biophysical Mechanisms of Class C G Protein-Coupled Receptor Function. Trends Biochem Sci 2020; 45:1049-1064. [PMID: 32861513 PMCID: PMC7642020 DOI: 10.1016/j.tibs.2020.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Groundbreaking structural and spectroscopic studies of class A G protein-coupled receptors (GPCRs), such as rhodopsin and the β2 adrenergic receptor, have provided a picture of how structural rearrangements between transmembrane helices control ligand binding, receptor activation, and effector coupling. However, the activation mechanism of other GPCR classes remains more elusive, in large part due to complexity in their domain assembly and quaternary structure. In this review, we focus on the class C GPCRs, which include metabotropic glutamate receptors (mGluRs) and gamma-aminobutyric acid B (GABAB) receptors (GABABRs) most prominently. We discuss the unique biophysical questions raised by the presence of large extracellular ligand-binding domains (LBDs) and constitutive homo/heterodimerization. Furthermore, we discuss how recent studies have begun to unravel how these fundamental class C GPCR features impact the processes of ligand binding, receptor activation, signal transduction, regulation by accessory proteins, and crosstalk with other GPCRs.
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Affiliation(s)
- Amr Ellaithy
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Javier Gonzalez-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Diomedes A Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA; Department of Chemistry and Chemical Biology, College of Science and Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA.
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29
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Kurth M, Lolicato F, Sandoval-Perez A, Amaya-Espinosa H, Teslenko A, Sinning I, Beck R, Brügger B, Aponte-Santamaría C. Cholesterol Localization around the Metabotropic Glutamate Receptor 2. J Phys Chem B 2020; 124:9061-9078. [PMID: 32954729 DOI: 10.1021/acs.jpcb.0c05264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The metabotropic glutamate receptor (mGluR) 2 plays a key role in the central nervous system. mGluR2 has been shown to be regulated by its surrounding lipid environment, especially by cholesterol, by an unknown mechanism. Here, using a combination of biochemical approaches, photo-cross-linking experiments, and molecular dynamics simulations we show the interaction of cholesterol with at least two, but potentially five more, preferential sites on the mGluR2 transmembrane domain. Our simulations demonstrate that surface matching, rather than electrostatic interactions with specific amino acids, is the main factor defining cholesterol localization. Moreover, the cholesterol localization observed here is similar to the sterol-binding pattern previously described in silico for other members of the mGluR family. Biochemical assays suggest little influence of cholesterol on trafficking or dimerization of mGluR2. Nevertheless, simulations revealed a significant reduction of residue-residue contacts together with an alteration in the internal mechanical stress at the cytoplasmic side of the helical bundle when cholesterol was present in the membrane. These alterations may be related to destabilization of the basal state of mGluR2. Due to the high sequence conservation of the transmembrane domains of mGluRs, the molecular interaction of cholesterol and mGluR2 described here is also likely to be relevant for other members of the mGLuR family.
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Affiliation(s)
- Markus Kurth
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Fabio Lolicato
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Angelica Sandoval-Perez
- Max Planck Tandem Group in Computational Biophysics, University of Los Andes, Bogotá, Colombia
| | - Helman Amaya-Espinosa
- Max Planck Tandem Group in Computational Biophysics, University of Los Andes, Bogotá, Colombia
| | - Alexandra Teslenko
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Irmgard Sinning
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Rainer Beck
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Britta Brügger
- Biochemistry Center (BZH), Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Camilo Aponte-Santamaría
- Max Planck Tandem Group in Computational Biophysics, University of Los Andes, Bogotá, Colombia.,Interdisciplinary Center for Scientific Computing, University of Heidelberg, Heidelberg, Germany
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30
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Perpiñá-Viciano C, Işbilir A, Zarca A, Caspar B, Kilpatrick LE, Hill SJ, Smit MJ, Lohse MJ, Hoffmann C. Kinetic Analysis of the Early Signaling Steps of the Human Chemokine Receptor CXCR4. Mol Pharmacol 2020; 98:72-87. [PMID: 32474443 PMCID: PMC7330677 DOI: 10.1124/mol.119.118448] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 05/06/2020] [Indexed: 01/14/2023] Open
Abstract
G protein–coupled receptors (GPCRs) are biologic switches that transduce extracellular stimuli into intracellular responses in the cell. Temporally resolving GPCR transduction pathways is key to understanding how cell signaling occurs. Here, we investigate the kinetics and dynamics of the activation and early signaling steps of the CXC chemokine receptor (CXCR) 4 in response to its natural ligands CXC chemokine ligand (CXCL) 12 and macrophage migration inhibitory factor (MIF), using Förster resonance energy transfer–based approaches. We show that CXCR4 presents a multifaceted response to CXCL12, with receptor activation (≈0.6 seconds) followed by a rearrangement in the receptor/G protein complex (≈1 seconds), a slower dimer rearrangement (≈1.7 seconds), and prolonged G protein activation (≈4 seconds). In comparison, MIF distinctly modulates every step of the transduction pathway, indicating distinct activation mechanisms and reflecting the different pharmacological properties of these two ligands. Our study also indicates that CXCR4 exhibits some degree of ligand-independent activity, a relevant feature for drug development.
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Affiliation(s)
- Cristina Perpiñá-Viciano
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Ali Işbilir
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Aurélien Zarca
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Birgit Caspar
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Laura E Kilpatrick
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Stephen J Hill
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Martine J Smit
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Martin J Lohse
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
| | - Carsten Hoffmann
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
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31
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Lei T, Hu Z, Ding R, Chen J, Li S, Zhang F, Pu X, Zhao N. Exploring the Activation Mechanism of a Metabotropic Glutamate Receptor Homodimer via Molecular Dynamics Simulation. ACS Chem Neurosci 2020; 11:133-145. [PMID: 31815422 DOI: 10.1021/acschemneuro.9b00425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Metabotropic glutamate receptors of class C GPCRs exist as constitutive dimers, which play important roles in activating excitatory synapses of the central nervous system. However, the activation mechanism induced by agonists has not been clarified in experiments. To address the problem, we used microsecond all-atom molecular dynamics (MD) simulation couple with protein structure network (PSN) to explore the glutamate-induced activation for the mGluR1 homodimer. The results indicate that glutamate binding stabilizes not only the closure of Venus flytrap domains but also the polar interaction of LB2-LB2, in turn keeping the extracelluar domain in the active state. The activation of the extracelluar domain drives transmembrane domains (TMDs) of the two protomers closer and induces asymmetric activation for the TMD domains of the two protomers. One protomer with lower binding affinity to the agonist is activated, while the other protomer with higher binding energy is still in the inactive state. The PSN analysis identifies the allosteric regulation pathway from the ligand-binding pocket in the extracellular domain to the G-protein binding site in the intracellular TMD region and further reveals that the asymmetric activation is attributed to a combination of trans-pathway and cis-pathway regulations from two glumatates, rather than a single activation pathway. These observations could provide valuable molecular information for understanding of the structure and the implications in drug efficacy for the class C GPCR dimers.
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Affiliation(s)
- Ting Lei
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Zhenxin Hu
- College of Computer Science, Sichuan University, Chengdu 610064, China
| | - Ruolin Ding
- West China School of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jianfang Chen
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shiqi Li
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Fuhui Zhang
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xuemei Pu
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Nanrong Zhao
- College of Chemistry, Sichuan University, Chengdu 610064, China
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32
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Neyman S, Braunewell KH, O'Connell KE, Dev KK, Manahan-Vaughan D. Inhibition of the Interaction Between Group I Metabotropic Glutamate Receptors and PDZ-Domain Proteins Prevents Hippocampal Long-Term Depression, but Not Long-Term Potentiation. Front Synaptic Neurosci 2019; 11:13. [PMID: 31057390 PMCID: PMC6482240 DOI: 10.3389/fnsyn.2019.00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/04/2019] [Indexed: 01/07/2023] Open
Abstract
The group I metabotropic glutamate (mGlu) receptor subtypes, mGlu1 and mGlu5, strongly regulate hippocampal synaptic plasticity. Both harbor PSD-95/discs-large/ZO-1 (PDZ) motifs at their extreme carboxyl terminals, which allow interaction with the PDZ domain of Tamalin, regulate the cell surface expression of group I mGlu receptors, and may modulate their coupling to signaling proteins. We investigated the functional role of this interaction in hippocampal long-term depression (LTD). Acute intracerebral treatment of adult rats with a cell-permeable PDZ-blocking peptide (pep-mGluR-STL), designed to competitively inhibit the interaction between Tamalin and group 1 mGlu receptors, prevented expression of LTD in the hippocampal CA1 region without affecting long-term potentiation (LTP) or basal synaptic transmission. Pep-mGluR-STL prevented facilitation by the group I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), and the mGlu5 agonist, (R,S)-2-chloro-5-Hydroxyphenylglycine (CHPG), of short-term depression (STD) into LTD, suggesting that Tamalin preferentially acts by mediating signaling through mGlu5. These data support that Tamalin is essential for the persistent expression of LTD and that it subserves the effective signaling of group 1 mGlu receptors.
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Affiliation(s)
- Sergey Neyman
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Karl-Heinz Braunewell
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Kara E O'Connell
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - Kumlesh K Dev
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
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33
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Pin JP, Kniazeff J, Prézeau L, Liu JF, Rondard P. GPCR interaction as a possible way for allosteric control between receptors. Mol Cell Endocrinol 2019; 486:89-95. [PMID: 30849406 DOI: 10.1016/j.mce.2019.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/17/2022]
Abstract
For more than twenty years now, GPCR dimers and larger oligomers have been the subject of intense debates. Evidence for a role of such complexes in receptor trafficking to and from the plasma membrane have been provided. However, one main issue is of course to determine whether or not such a phenomenon can be responsible for an allosteric and reciprocal control (allosteric control) of the subunits. Such a possibility would indeed add to the possible ways a cell integrates various signals targeting GPCRs. Among the large GPCR family, the class C receptors that include mGlu and GABAB receptors, represent excellent models to examine such a possibility as they are mandatory dimers. In the present review, we will report on the observed allosteric interaction between the subunits of class C GPCRs, both mGluRs and GABABRs, and on the structural bases of these interactions. We will then discuss these findings for other GPCR types such as the rhodopsin-like class A receptors. We will show that many of the observations made with class C receptors have also been reported with class A receptors, suggesting that the mechanisms involved in the allosteric control between subunits in GPCR dimers may not be unique to class C GPCRs.
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Affiliation(s)
- Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Laurent Prézeau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jiang-Feng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
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34
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Park J, Selvam B, Sanematsu K, Shigemura N, Shukla D, Procko E. Structural architecture of a dimeric class C GPCR based on co-trafficking of sweet taste receptor subunits. J Biol Chem 2019; 294:4759-4774. [PMID: 30723160 DOI: 10.1074/jbc.ra118.006173] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/24/2019] [Indexed: 01/06/2023] Open
Abstract
Class C G protein-coupled receptors (GPCRs) are obligatory dimers that are particularly important for neuronal responses to endogenous and environmental stimuli. Ligand recognition through large extracellular domains leads to the reorganization of transmembrane regions to activate G protein signaling. Although structures of individual domains are known, the complete architecture of a class C GPCR and the mechanism of interdomain coupling during receptor activation are unclear. By screening a mutagenesis library of the human class C sweet taste receptor subunit T1R2, we enhanced surface expression and identified a dibasic intracellular retention motif that modulates surface expression and co-trafficking with its heterodimeric partner T1R3. Using a highly expressed T1R2 variant, dimerization sites along the entire subunit within all the structural domains were identified by a comprehensive mutational scan for co-trafficking with T1R3 in human cells. The data further reveal that the C terminus of the extracellular cysteine-rich domain needs to be properly folded for T1R3 dimerization and co-trafficking, but not for surface expression of T1R2 alone. These results guided the modeling of the T1R2-T1R3 dimer in living cells, which predicts a twisted arrangement of domains around the central axis, and a continuous folded structure between transmembrane domain loops and the cysteine-rich domains. These insights have implications for how conformational changes between domains are coupled within class C GPCRs.
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Affiliation(s)
- Jihye Park
- From the Departments of Biochemistry and
| | - Balaji Selvam
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | - Keisuke Sanematsu
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriatsu Shigemura
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Diwakar Shukla
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
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35
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Gregory K, Kufareva I, Keller AN, Khajehali E, Mun HC, Goolam MA, Mason RS, Capuano B, Conigrave AD, Christopoulos A, Leach K. Dual Action Calcium-Sensing Receptor Modulator Unmasks Novel Mode-Switching Mechanism. ACS Pharmacol Transl Sci 2018; 1:96-109. [PMID: 32219206 PMCID: PMC7089027 DOI: 10.1021/acsptsci.8b00021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Indexed: 12/17/2022]
Abstract
Negative allosteric modulators (NAMs) of the human calcium-sensing receptor (CaSR) have previously failed to show efficacy in human osteoporosis clinical trials, but there is now significant interest in repurposing these drugs for hypocalcemic disorders and inflammatory lung diseases. However, little is known about how CaSR NAMs inhibit the response to endogenous activators. An improved understanding of CaSR negative allosteric modulation may afford the opportunity to develop therapeutically superior CaSR-targeting drugs. In an attempt to elucidate the mechanistic and structural basis of allosteric modulation mediated by the previously reported NAM, calhex231, we herein demonstrate that calhex231 actually potentiates or inhibits the activity of multiple CaSR agonists depending on whether it occupies one or both protomers in a CaSR dimer. These findings reveal a novel mechanism of mode-switching at a Class C G protein-coupled receptor that has implications for drug discovery and potential clinical utility.
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Affiliation(s)
- Karen
J. Gregory
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
| | - Irina Kufareva
- Skaggs
School of Pharmacy & Pharmaceutical Sciences, University of California, 9500 Gilman Drive, La Jolla, San Diego, California MC 0747, United States
| | - Andrew N. Keller
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
| | - Elham Khajehali
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
| | - Hee-Chang Mun
- School of Life and Environmental
Sciences, Charles Perkins Centre, and Physiology and
Bosch Institute, Building F13, University
of Sydney, Sidney, New South Wales 2006, Australia
| | - Mahvash A. Goolam
- School of Life and Environmental
Sciences, Charles Perkins Centre, and Physiology and
Bosch Institute, Building F13, University
of Sydney, Sidney, New South Wales 2006, Australia
| | - Rebecca S. Mason
- School of Life and Environmental
Sciences, Charles Perkins Centre, and Physiology and
Bosch Institute, Building F13, University
of Sydney, Sidney, New South Wales 2006, Australia
| | - Ben Capuano
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
| | - Arthur D. Conigrave
- School of Life and Environmental
Sciences, Charles Perkins Centre, and Physiology and
Bosch Institute, Building F13, University
of Sydney, Sidney, New South Wales 2006, Australia
| | - Arthur Christopoulos
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
| | - Katie Leach
- Drug
Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Monash University, Parkville, Victoria 3052, Australia
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36
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Lensing CJ, Freeman KT, Schnell SM, Speth RC, Zarth AT, Haskell-Luevano C. Developing a Biased Unmatched Bivalent Ligand (BUmBL) Design Strategy to Target the GPCR Homodimer Allosteric Signaling (cAMP over β-Arrestin 2 Recruitment) Within the Melanocortin Receptors. J Med Chem 2018; 62:144-158. [PMID: 29669202 DOI: 10.1021/acs.jmedchem.8b00238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Understanding the functional relevance of G protein-coupled receptor (GPCR) homodimerization has been limited by the insufficient tools to assess asymmetric signaling occurring within dimers comprised of the same receptor type. We present unmatched bivalent ligands (UmBLs) to study the asymmetric function of melanocortin homodimers. UmBLs contain one agonist and one antagonist pharmacophore designed to target a melanocortin homodimer such that one receptor is occupied by an agonist and the other receptor by an antagonist pharmacophore. First-in-class biased UmBLs (BUmBLs) targeting the human melanocortin-4 receptor (hMC4R) were discovered. The BUmBLs displayed biased agonism by potently stimulating cAMP signaling (EC50 ∼ 2-6 nM) but minimally activating the β-arrestin recruitment pathway (≤55% maximum signal at 10 μM). To our knowledge, we report the first single-compound strategy to pharmacologically target melanocortin receptor allosteric signaling that occurs between homodimers that can be applied straightforwardly in vitro and in vivo to other GPCR systems.
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Affiliation(s)
- Cody J Lensing
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Katie T Freeman
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Sathya M Schnell
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Robert C Speth
- College of Pharmacy , Nova Southeastern University , Fort Lauderdale , Florida 33328-2018 , United States.,Department of Pharmacology and Physiology , Georgetown University , Washington, D.C. 20057 , United States
| | - Adam T Zarth
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States.,Masonic Cancer Center , University of Minnesota , 2231 Sixth Street SE, 2-210 CCRB , Minneapolis , Minnesota 55455 , United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
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37
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Hellyer SD, Albold S, Wang T, Chen ANY, May LT, Leach K, Gregory KJ. “Selective” Class C G Protein-Coupled Receptor Modulators Are Neutral or Biased mGlu5 Allosteric Ligands. Mol Pharmacol 2018. [DOI: 10.1124/mol.117.111518] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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38
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Liu J, Zhang Z, Moreno-Delgado D, Dalton JA, Rovira X, Trapero A, Goudet C, Llebaria A, Giraldo J, Yuan Q, Rondard P, Huang S, Liu J, Pin JP. Allosteric control of an asymmetric transduction in a G protein-coupled receptor heterodimer. eLife 2017; 6:26985. [PMID: 28829739 PMCID: PMC5582870 DOI: 10.7554/elife.26985] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023] Open
Abstract
GPCRs play critical roles in cell communication. Although GPCRs can form heteromers, their role in signaling remains elusive. Here we used rat metabotropic glutamate (mGlu) receptors as prototypical dimers to study the functional interaction between each subunit. mGluRs can form both constitutive homo- and heterodimers. Whereas both mGlu2 and mGlu4 couple to G proteins, G protein activation is mediated by mGlu4 heptahelical domain (HD) exclusively in mGlu2-4 heterodimers. Such asymmetric transduction results from the action of both the dimeric extracellular domain, and an allosteric activation by the partially-activated non-functional mGlu2 HD. G proteins activation by mGlu2 HD occurs if either the mGlu2 HD is occupied by a positive allosteric modulator or if mGlu4 HD is inhibited by a negative modulator. These data revealed an oriented asymmetry in mGlu heterodimers that can be controlled with allosteric modulators. They provide new insight on the allosteric interaction between subunits in a GPCR dimer.
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Affiliation(s)
- Junke Liu
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Zongyong Zhang
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - David Moreno-Delgado
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - James Ar Dalton
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Barcelona, Spain.,Network Biomedical Research Center on Mental Health, Barcelona, Spain
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Ana Trapero
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Cyril Goudet
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Jesús Giraldo
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Barcelona, Spain.,Network Biomedical Research Center on Mental Health, Barcelona, Spain
| | - Qilin Yuan
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Siluo Huang
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
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39
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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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40
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Takezako T, Unal H, Karnik SS, Node K. Current topics in angiotensin II type 1 receptor research: Focus on inverse agonism, receptor dimerization and biased agonism. Pharmacol Res 2017. [PMID: 28648738 DOI: 10.1016/j.phrs.2017.06.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although the octapeptide hormone angiotensin II (Ang II) regulates cardiovascular and renal homeostasis through the Ang II type 1 receptor (AT1R), overstimulation of AT1R causes various human diseases, such as hypertension and cardiac hypertrophy. Therefore, AT1R blockers (ARBs) have been widely used as therapeutic drugs for these diseases. Recent basic research and clinical studies have resulted in the discovery of interesting phenomena associated with AT1R function. For example, ligand-independent activation of AT1R by mechanical stress and agonistic autoantibodies, as well as via receptor mutations, has been shown to decrease the inverse agonistic efficacy of ARBs, though the molecular mechanisms of such phenomena had remained elusive until recently. Furthermore, although AT1R is believed to exist as a monomer, recent studies have demonstrated that AT1R can homodimerize and heterodimerize with other G-protein coupled receptors (GPCR), altering the receptor signaling properties. Therefore, formation of both AT1R homodimers and AT1R-GPCR heterodimer may be involved in the pathogenesis of human disease states, such as atherosclerosis and preeclampsia. Finally, biased AT1R ligands that can preferentially activate the β-arrestin-mediated signaling pathway have been discovered. Such β-arrestin-biased AT1R ligands may be better therapeutic drugs for cardiovascular diseases. New findings on AT1R described herein could provide a conceptual framework for application of ARBs in the treatment of diseases, as well as for novel drug development. Since AT1R is an extensively studied member of the GPCR superfamily encoded in the human genome, this review is relevant for understanding the functions of other members of this superfamily.
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Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart Research, Saga University, Saga, Japan; Medical Center for Student Health, Kobe University, Kobe, Japan.
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Koichi Node
- Department of Cardiovascular Medicine, Saga University, Japan
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Investigating the molecular mechanism of positive and negative allosteric modulators in the calcium-sensing receptor dimer. Sci Rep 2017; 7:46355. [PMID: 28417952 PMCID: PMC5394417 DOI: 10.1038/srep46355] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/20/2017] [Indexed: 11/09/2022] Open
Abstract
Allosteric modulators that are targeting the calcium-sensing receptor (CaSR) hold great therapeutic potential, and elucidating the molecular basis for modulation would thus benefit the development of novel therapeutics. In the present study, we aimed at investigating the mechanism of allosteric modulation in CaSR by testing dimers carrying mutations in the allosteric site of one or both of the subunits. To ensure measurements on a well-defined dimer composition, we applied a trans-activation system in which only the specific heterodimer of two loss-of-function mutants responded to agonist. Although one of these mutants was potentiated by a positive allosteric modulator, we showed that receptor activity was further potentiated in a trans-activation heterodimer containing a single allosteric site, however only when the allosteric site was located in the subunit responsible for G protein coupling. On the contrary, preventing activation in both subunits was necessary for obtaining full inhibition by a negative allosteric modulator. These findings correlate with the proposed activation mechanism of the metabotropic glutamate receptors (mGluRs), in which only a single transmembrane domain is activated at a time. CaSR and mGluRs belong to the class C G protein-coupled receptors, and our findings thus suggest that the activation mechanism is common to this subfamily.
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Class C G protein-coupled receptors: reviving old couples with new partners. BIOPHYSICS REPORTS 2017; 3:57-63. [PMID: 29238742 PMCID: PMC5719802 DOI: 10.1007/s41048-017-0036-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/11/2017] [Indexed: 02/02/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are key players in cell communication and are encoded by the largest family in our genome. As such, GPCRs represent the main targets in drug development programs. Sequence analysis revealed several classes of GPCRs: the class A rhodopsin-like receptors represent the majority, the class B includes the secretin-like and adhesion GPCRs, the class F includes the frizzled receptors, and the class C includes receptors for the main neurotransmitters, glutamate and GABA, and those for sweet and umami taste and calcium receptors. Class C receptors are far more complex than other GPCRs, being mandatory dimers, with each subunit being composed of several domains. In this review, we summarize our actual knowledge regarding the activation mechanism and subunit organization of class C GPCRs, and how this brings information for many other GPCRs.
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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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44
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Pin JP, Bettler B. Organization and functions of mGlu and GABAB receptor complexes. Nature 2016; 540:60-68. [DOI: 10.1038/nature20566] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 10/21/2016] [Indexed: 02/08/2023]
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Lindsley CW, Emmitte KA, Hopkins CR, Bridges TM, Gregory KJ, Niswender CM, Conn PJ. Practical Strategies and Concepts in GPCR Allosteric Modulator Discovery: Recent Advances with Metabotropic Glutamate Receptors. Chem Rev 2016; 116:6707-41. [PMID: 26882314 PMCID: PMC4988345 DOI: 10.1021/acs.chemrev.5b00656] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Allosteric modulation of GPCRs has initiated a new era of basic and translational discovery, filled with therapeutic promise yet fraught with caveats. Allosteric ligands stabilize unique conformations of the GPCR that afford fundamentally new receptors, capable of novel pharmacology, unprecedented subtype selectivity, and unique signal bias. This review provides a comprehensive overview of the basics of GPCR allosteric pharmacology, medicinal chemistry, drug metabolism, and validated approaches to address each of the major challenges and caveats. Then, the review narrows focus to highlight recent advances in the discovery of allosteric ligands for metabotropic glutamate receptor subtypes 1-5 and 7 (mGlu1-5,7) highlighting key concepts ("molecular switches", signal bias, heterodimers) and practical solutions to enable the development of tool compounds and clinical candidates. The review closes with a section on late-breaking new advances with allosteric ligands for other GPCRs and emerging data for endogenous allosteric modulators.
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Affiliation(s)
- Craig W. Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, Texas 76107, United States
| | - Corey R. Hopkins
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Thomas M. Bridges
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Karen J. Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville VIC 3052, Australia
| | - Colleen M. Niswender
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - P. Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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46
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O'Brien DE, Conn PJ. Neurobiological Insights from mGlu Receptor Allosteric Modulation. Int J Neuropsychopharmacol 2016; 19:pyv133. [PMID: 26647381 PMCID: PMC4886670 DOI: 10.1093/ijnp/pyv133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/15/2015] [Accepted: 12/02/2015] [Indexed: 12/25/2022] Open
Abstract
Allosteric modulation of metabotropic glutamate (mGlu) receptors offers a promising pharmacological approach to normalize neural circuit dysfunction associated with various psychiatric and neurological disorders. As mGlu receptor allosteric modulators progress through discovery and clinical development, both technical advances and novel tool compounds are providing opportunities to better understand mGlu receptor pharmacology and neurobiology. Recent advances in structural biology are elucidating the structural determinants of mGlu receptor-negative allosteric modulation and supplying the means to resolve active, allosteric modulator-bound mGlu receptors. The discovery and characterization of allosteric modulators with novel pharmacological profiles is uncovering the biological significance of their intrinsic agonist activity, biased mGlu receptor modulation, and novel mGlu receptor heterodimers. The development and exploitation of optogenetic and optopharmacological tools is permitting a refined spatial and temporal understanding of both mGlu receptor functions and their allosteric modulation in intact brain circuits. Together, these lines of research promise to provide a more refined understanding of mGlu receptors and their allosteric modulation that will inform the development of mGlu receptor allosteric modulators as neurotherapeutics in the years to come.
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Affiliation(s)
- Daniel E O'Brien
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee (Drs O'Brien and Conn)
| | - P Jeffrey Conn
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee (Drs O'Brien and Conn).
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47
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Doornbos MLJ, Pérez-Benito L, Tresadern G, Mulder-Krieger T, Biesmans I, Trabanco AA, Cid JM, Lavreysen H, IJzerman AP, Heitman LH. Molecular mechanism of positive allosteric modulation of the metabotropic glutamate receptor 2 by JNJ-46281222. Br J Pharmacol 2016; 173:588-600. [PMID: 26589404 DOI: 10.1111/bph.13390] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 11/09/2015] [Accepted: 11/10/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND AND PURPOSE Allosteric modulation of the mGlu2 receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [(3) H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode. EXPERIMENTAL APPROACH We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222. KEY RESULTS JNJ-46281222 is an mGlu2 -selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [(3) H]-JNJ-46281222 was increased by the presence of glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [(3) H]-JNJ-46281222 binding experiments on mutant receptors. CONCLUSION AND IMPLICATIONS Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C receptor drug discovery.
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Affiliation(s)
- Maarten L J Doornbos
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | - Laura Pérez-Benito
- Janssen Research and Development, Toledo, Spain.,Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra, Spain
| | | | - Thea Mulder-Krieger
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | | | | | | | | | - Adriaan P IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | - Laura H Heitman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
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48
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Zhang XC, Liu J, Jiang D. Why is dimerization essential for class-C GPCR function? New insights from mGluR1 crystal structure analysis. Protein Cell 2015; 5:492-5. [PMID: 24805307 PMCID: PMC4085282 DOI: 10.1007/s13238-014-0062-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China,
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49
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Bellot M, Galandrin S, Boularan C, Matthies HJ, Despas F, Denis C, Javitch J, Mazères S, Sanni SJ, Pons V, Seguelas MH, Hansen JL, Pathak A, Galli A, Sénard JM, Galés C. Dual agonist occupancy of AT1-R-α2C-AR heterodimers results in atypical Gs-PKA signaling. Nat Chem Biol 2015; 11:271-9. [PMID: 25706338 DOI: 10.1038/nchembio.1766] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/09/2015] [Indexed: 12/25/2022]
Abstract
Hypersecretion of norepinephrine (NE) and angiotensin II (AngII) is a hallmark of major prevalent cardiovascular diseases that contribute to cardiac pathophysiology and morbidity. Herein, we explore whether heterodimerization of presynaptic AngII AT1 receptor (AT1-R) and NE α2C-adrenergic receptor (α2C-AR) could underlie their functional cross-talk to control NE secretion. Multiple bioluminescence resonance energy transfer and protein complementation assays allowed us to accurately probe the structures and functions of the α2C-AR-AT1-R dimer promoted by ligand binding to individual protomers. We found that dual agonist occupancy resulted in a conformation of the heterodimer different from that induced by active individual protomers and triggered atypical Gs-cAMP-PKA signaling. This specific pharmacological signaling unit was identified in vivo to promote not only NE hypersecretion in sympathetic neurons but also sympathetic hyperactivity in mice. Thus, we uncovered a new process by which GPCR heterodimerization creates an original functional pharmacological entity and that could constitute a promising new target in cardiovascular therapeutics.
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Affiliation(s)
- Morgane Bellot
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Ségolène Galandrin
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Cédric Boularan
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Heinrich J Matthies
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Fabien Despas
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Colette Denis
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jonathan Javitch
- 1] Center for Molecular Recognition and Departments of Psychiatry and Pharmacology, Columbia University, New York, New York, USA. [2] College of Physicians and Surgeons, Columbia University, New York, New York, USA. [3] Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Serge Mazères
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, UMR 508, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Samra Joke Sanni
- 1] Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark. [2] Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Véronique Pons
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Marie-Hélène Seguelas
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jakob L Hansen
- Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Atul Pathak
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Aurelio Galli
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [3] Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [4] Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jean-Michel Sénard
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
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50
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Xue L, Rovira X, Scholler P, Zhao H, Liu J, Pin JP, Rondard P. Major ligand-induced rearrangement of the heptahelical domain interface in a GPCR dimer. Nat Chem Biol 2015; 11:134-40. [PMID: 25503927 DOI: 10.1038/nchembio.1711] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/14/2014] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are major players in cell communication. Although they form functional monomers, increasing evidence indicates that GPCR dimerization has a critical role in cooperative phenomena that are important for cell signal integration. However, the structural bases of these phenomena remain elusive. Here, using well-characterized receptor dimers, the metabotropic glutamate receptors (mGluRs), we show that structural changes at the dimer interface are linked to receptor activation. We demonstrate that the main dimer interface is formed by transmembrane α helix 4 (TM4) and TM5 in the inactive state and by TM6 in the active state. This major change in the dimer interface is required for receptor activity because locking the TM4-TM5 interface prevents activation by agonist, whereas locking the TM6 interface leads to a constitutively active receptor. These data provide important information on the activation mechanism of mGluRs and improve our understanding of the structural basis of the negative cooperativity observed in these GPCR dimers.
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MESH Headings
- Alanine/genetics
- Animals
- COS Cells
- Chlorocebus aethiops
- Cysteine/genetics
- HEK293 Cells
- Humans
- Ligands
- Models, Molecular
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Multimerization
- Protein Structure, Tertiary
- Protein Subunits
- Rats
- Receptor, Metabotropic Glutamate 5/agonists
- Receptor, Metabotropic Glutamate 5/chemistry
- Receptor, Metabotropic Glutamate 5/genetics
- Receptors, GABA-B/chemistry
- Receptors, GABA-B/genetics
- Receptors, GABA-B/metabolism
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Transcriptional Activation
- Transfection
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Affiliation(s)
- Li Xue
- 1] Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. [2] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [3] INSERM, U661, Montpellier, France. [4] Université Montpellier 1 &2, Montpellier, France
| | - Xavier Rovira
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Pauline Scholler
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Han Zhao
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Philippe Rondard
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
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