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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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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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3
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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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4
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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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5
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Guidolin D, Tortorella C, Marcoli M, Cervetto C, Maura G, Agnati LF. Receptor-receptor interactions and microvesicle exchange as mechanisms modulating signaling between neurons and astrocytes. Neuropharmacology 2023; 231:109509. [PMID: 36935005 DOI: 10.1016/j.neuropharm.2023.109509] [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: 12/17/2022] [Revised: 02/21/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023]
Abstract
It is well known that astrocytes play a significant metabolic role in the nervous tissue, maintaining the homeostasis of the extracellular space and of the blood-brain barrier, and providing trophic support to neurons. In addition, however, evidence exists indicating astrocytes as important elements for brain activity through signaling exchange with neurons. Astrocytes, indeed, can sense synaptic activity and their molecular machinery responds to neurotransmitters released by neurons with cytoplasmic Ca2+ elevations that, in turn, stimulate the release of neuroactive substances (gliotransmitters) influencing nearby neurons. In both cell types the recognition and transduction of this complex pattern of signals is mediated by specific receptors that are also involved in mechanisms tuning the intercellular cross-talk between astrocytes and neurons. Two of these mechanisms are the focus of the present discussion. The first concerns direct receptor-receptor interactions leading to the formation at the cell membrane of multimeric receptor complexes. The cooperativity that emerges in the actions of orthosteric and allosteric ligands of the monomers forming the assembly provides the cell decoding apparatus with sophisticated and flexible dynamics in terms of recognition and signal transduction pathways. A further mechanism of plasticity involving receptors is based on the transfer of elements of the cellular signaling apparatus via extracellular microvesicles acting as protective containers, which can lead to transient changes in the transmitting/decoding capabilities of the target cell.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121, Padova, Italy.
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121, Padova, Italy
| | - Manuela Marcoli
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126, Genova, Italy
| | - Chiara Cervetto
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126, Genova, Italy
| | - Guido Maura
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126, Genova, Italy
| | - Luigi F Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
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6
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Caniceiro AB, Bueschbell B, Schiedel AC, Moreira IS. Class A and C GPCR Dimers in Neurodegenerative Diseases. Curr Neuropharmacol 2022; 20:2081-2141. [PMID: 35339177 PMCID: PMC9886835 DOI: 10.2174/1570159x20666220327221830] [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: 09/14/2021] [Revised: 02/21/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.
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Affiliation(s)
- Ana B. Caniceiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Beatriz Bueschbell
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Irina S. Moreira
- University of Coimbra, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; ,Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal,Address correspondence to this author at the Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal; E-mail:
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7
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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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9
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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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10
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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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11
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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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12
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Orgován Z, Ferenczy GG, Keserű GM. Allosteric Molecular Switches in Metabotropic Glutamate Receptors. ChemMedChem 2021; 16:81-93. [PMID: 32686363 PMCID: PMC7818470 DOI: 10.1002/cmdc.202000444] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Indexed: 12/22/2022]
Abstract
Metabotropic glutamate receptors (mGlu) are class C G protein-coupled receptors of eight subtypes that are omnipresently expressed in the central nervous system. mGlus have relevance in several psychiatric and neurological disorders, therefore they raise considerable interest as drug targets. Allosteric modulators of mGlus offer advantages over orthosteric ligands owing to their increased potential to achieve subtype selectivity, and this has prompted discovery programs that have produced a large number of reported allosteric mGlu ligands. However, the optimization of allosteric ligands into drug candidates has proved to be challenging owing to induced-fit effects, flat or steep structure-activity relationships and unexpected changes in theirpharmacology. Subtle structural changes identified as molecular switches might modulate the functional activity of allosteric ligands. Here we review these switches discovered in the metabotropic glutamate receptor family..
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Affiliation(s)
- Zoltán Orgován
- Medicinal Chemistry Research GroupResearch Centre for Natural SciencesMagyar tudósok krt. 2Budapest1117Hungary
| | - György G. Ferenczy
- Medicinal Chemistry Research GroupResearch Centre for Natural SciencesMagyar tudósok krt. 2Budapest1117Hungary
| | - György M. Keserű
- Medicinal Chemistry Research GroupResearch Centre for Natural SciencesMagyar tudósok krt. 2Budapest1117Hungary
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13
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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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14
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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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15
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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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16
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Conradi Smith GD. Allostery in oligomeric receptor models. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2020; 37:313-333. [PMID: 31822901 DOI: 10.1093/imammb/dqz016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 10/03/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
We show how equilibrium binding curves of receptor homodimers can be expressed as rational polynomial functions of the equilibrium binding curves of the constituent monomers, without approximation and without assuming independence of receptor monomers. Using a distinguished spanning tree construction for reduced graph powers, the method properly accounts for thermodynamic constraints and allosteric interactions between receptor monomers (i.e. conformational coupling). The method is completely general; it begins with an arbitrary undirected graph representing the topology of a monomer state-transition diagram and ends with an algebraic expression for the equilibrium binding curve of a receptor oligomer composed of two or more identical and indistinguishable monomers. Several specific examples are analysed, including guanine nucleotide-binding protein-coupled receptor dimers and tetramers composed of multiple 'ternary complex' monomers.
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17
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Laboute T, Gandía J, Pellissier LP, Corde Y, Rebeillard F, Gallo M, Gauthier C, Léauté A, Diaz J, Poupon A, Kieffer BL, Le Merrer J, Becker JA. The orphan receptor GPR88 blunts the signaling of opioid receptors and multiple striatal GPCRs. eLife 2020; 9:50519. [PMID: 32003745 PMCID: PMC7012601 DOI: 10.7554/elife.50519] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
GPR88 is an orphan G protein-coupled receptor (GPCR) considered as a promising therapeutic target for neuropsychiatric disorders; its pharmacology, however, remains scarcely understood. Based on our previous report of increased delta opioid receptor activity in Gpr88 null mice, we investigated the impact of GPR88 co-expression on the signaling of opioid receptors in vitro and revealed that GPR88 inhibits the activation of both their G protein- and β-arrestin-dependent signaling pathways. In Gpr88 knockout mice, morphine-induced locomotor sensitization, withdrawal and supra-spinal analgesia were facilitated, consistent with a tonic inhibitory action of GPR88 on µOR signaling. We then explored GPR88 interactions with more striatal versus non-neuronal GPCRs, and revealed that GPR88 can decrease the G protein-dependent signaling of most receptors in close proximity, but impedes β-arrestin recruitment by all receptors tested. Our study unravels an unsuspected buffering role of GPR88 expression on GPCR signaling, with intriguing consequences for opioid and striatal functions.
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Affiliation(s)
- Thibaut Laboute
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France
| | - Jorge Gandía
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France
| | - Lucie P Pellissier
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France.,Biology and Bioinformatics of Signalling Systems, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Nouzilly, France
| | - Yannick Corde
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France
| | - Florian Rebeillard
- Cellular Biology and Molecular Pharmacology of central Receptors, Centre de Psychiatrie et Neurosciences, Inserm UMR_S894 - Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Maria Gallo
- Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona Biomedical Research Park, Barcelona, Spain
| | - Christophe Gauthier
- Biology and Bioinformatics of Signalling Systems, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Nouzilly, France
| | - Audrey Léauté
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France
| | - Jorge Diaz
- Cellular Biology and Molecular Pharmacology of central Receptors, Centre de Psychiatrie et Neurosciences, Inserm UMR_S894 - Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Poupon
- Biology and Bioinformatics of Signalling Systems, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Nouzilly, France
| | - Brigitte L Kieffer
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Canada.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR 7104, Inserm U1258, Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| | - Julie Le Merrer
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR 7104, Inserm U1258, Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
| | - Jérôme Aj Becker
- Deficits of Reward GPCRs and Sociability, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université de Tours, Inserm, Nouzilly, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR 7104, Inserm U1258, Université de Strasbourg, 1 rue Laurent Fries, Illkirch, France
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18
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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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19
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Dal Prà I, Armato U, Chiarini A. Family C G-Protein-Coupled Receptors in Alzheimer's Disease and Therapeutic Implications. Front Pharmacol 2019; 10:1282. [PMID: 31719824 PMCID: PMC6826475 DOI: 10.3389/fphar.2019.01282] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), particularly its sporadic or late-onset form (SAD/LOAD), is the most prevalent (96–98% of cases) neurodegenerative dementia in aged people. AD’s neuropathology hallmarks are intrabrain accumulation of amyloid-β peptides (Aβs) and of hyperphosphorylated Tau (p-Tau) proteins, diffuse neuroinflammation, and progressive death of neurons and oligodendrocytes. Mounting evidences suggest that family C G-protein-coupled receptors (GPCRs), which include γ-aminobutyric acid B receptors (GABABRs), metabotropic glutamate receptors (mGluR1-8), and the calcium-sensing receptor (CaSR), are involved in many neurotransmitter systems that dysfunction in AD. This review updates the available knowledge about the roles of GPCRs, particularly but not exclusively those expressed by brain astrocytes, in SAD/LOAD onset and progression, taking stock of their respective mechanisms of action and of their potential as anti-AD therapeutic targets. In particular, GABABRs prevent Aβs synthesis and neuronal hyperexcitability and group I mGluRs play important pathogenetic roles in transgenic AD-model animals. Moreover, the specific binding of Aβs to the CaSRs of human cortical astrocytes and neurons cultured in vitro engenders a pathological signaling that crucially promotes the surplus synthesis and release of Aβs and hyperphosphorylated Tau proteins, and also of nitric oxide, vascular endothelial growth factor-A, and proinflammatory agents. Concurrently, Aβs•CaSR signaling hinders the release of soluble (s)APP-α peptide, a neurotrophic agent and GABABR1a agonist. Altogether these effects progressively kill human cortical neurons in vitro and likely also in vivo. Several CaSR’s negative allosteric modulators suppress all the noxious effects elicited by Aβs•CaSR signaling in human cortical astrocytes and neurons thus safeguarding neurons’ viability in vitro and raising hopes about their potential therapeutic benefits in AD patients. Further basic and clinical investigations on these hot topics are needed taking always heed that activation of the several brain family C GPCRs may elicit divergent upshots according to the models studied.
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Affiliation(s)
- Ilaria Dal Prà
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
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20
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Borroto-Escuela DO, Fuxe K. Oligomeric Receptor Complexes and Their Allosteric Receptor-Receptor Interactions in the Plasma Membrane Represent a New Biological Principle for Integration of Signals in the CNS. Front Mol Neurosci 2019; 12:230. [PMID: 31607863 PMCID: PMC6773811 DOI: 10.3389/fnmol.2019.00230] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptors (GPCRs) not only exist as monomers but also as homomers and heteromers in which allosteric receptor-receptor interactions take place, modulating the functions of the participating GPCR protomers. GPCRs can also form heteroreceptor complexes with ionotropic receptors and receptor tyrosine kinases modulating their function. Furthermore, adaptor proteins interact with receptor protomers and modulate their interactions. The state of the art is that the allosteric receptor-receptor interactions are reciprocal, highly dynamic and substantially alter the signaling, trafficking, recognition and pharmacology of the participating protomers. The pattern of changes appears to be unique for each heteromer and can favor antagonistic or facilitatory interactions or switch the G protein coupling from e.g., Gi/o to Gq or to beta-arrestin signaling. It lends a new dimension to molecular integration in the nervous system. Future direction should be aimed at determining the receptor interface involving building models of selected heterodimers. This will make design of interface-interfering peptides that specifically disrupt the heterodimer possible. This will help to determine the functional role of the allosteric receptor-receptor interactions as well as the integration of signals at the plasma membrane by the heteroreceptor complexes, vs. integration of the intracellular signaling pathways. Integration of signals also at the plasma membrane seems crucial in view of the hypothesis that learning and memory at a molecular level takes place by reorganization of homo and heteroreceptor complexes in the postsynaptic membrane. Homo and heteroreceptor complexes are in balance with each other, and their disbalance is linked to disease. Targeting heteroreceptor complexes represents a novel strategy for the treatment of brain disorders.
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Affiliation(s)
- Dasiel O. Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, Urbino, Italy
- Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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21
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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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22
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Llinas Del Torrent C, Casajuana-Martin N, Pardo L, Tresadern G, Pérez-Benito L. Mechanisms Underlying Allosteric Molecular Switches of Metabotropic Glutamate Receptor 5. J Chem Inf Model 2019; 59:2456-2466. [PMID: 30811196 DOI: 10.1021/acs.jcim.8b00924] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The metabotropic glutamate 5 (mGlu5) receptor is a class C G protein-coupled receptor (GPCR) that is implicated in several CNS disorders making it a popular drug discovery target. Years of research have revealed allosteric mGlu5 ligands showing an unexpected complete switch in functional activity despite only small changes in their chemical structure, resulting in positive allosteric modulators (PAM) or negative allosteric modulators (NAM) for the same scaffold. Up to now, the origins of this effect are not understood, causing difficulties in a drug discovery context. In this work, experimental data was gathered and analyzed alongside docking and Molecular Dynamics (MD) calculations for three sets of PAM and NAM pairs. The results consistently show the role of specific interactions formed between ligand substituents and amino acid side chains that block or promote local movements associated with receptor activation. The work provides an explanation for how such small structural changes lead to remarkable differences in functional activity. While this work can greatly help drug discovery programs avoid these switches, it also provides valuable insight into the mechanisms of class C GPCR allosteric activation. Furthermore, the approach shows the value of applying MD to understand functional activity in drug design programs, even for such close structural analogues.
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Affiliation(s)
- Claudia Llinas Del Torrent
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Nil Casajuana-Martin
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Leonardo Pardo
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Gary Tresadern
- Computational Chemistry, Janssen Research & Development , Janssen Pharmaceutica N. V. , Turnhoutseweg 30 , B-2340 Beerse , Belgium
| | - Laura Pérez-Benito
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain.,Computational Chemistry, Janssen Research & Development , Janssen Pharmaceutica N. V. , Turnhoutseweg 30 , B-2340 Beerse , Belgium
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23
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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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24
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Biased agonism and allosteric modulation of metabotropic glutamate receptor 5. Clin Sci (Lond) 2018; 132:2323-2338. [PMID: 30389826 DOI: 10.1042/cs20180374] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 12/18/2022]
Abstract
Metabotropic glutamate receptors belong to class C G-protein-coupled receptors and consist of eight subtypes that are ubiquitously expressed throughout the central nervous system. In recent years, the metabotropic glutamate receptor subtype 5 (mGlu5) has emerged as a promising target for a broad range of psychiatric and neurological disorders. Drug discovery programs targetting mGlu5 are primarily focused on development of allosteric modulators that interact with sites distinct from the endogenous agonist glutamate. Significant efforts have seen mGlu5 allosteric modulators progress into clinical trials; however, recent failures due to lack of efficacy or adverse effects indicate a need for a better understanding of the functional consequences of mGlu5 allosteric modulation. Biased agonism is an interrelated phenomenon to allosterism, describing how different ligands acting through the same receptor can differentially influence signaling to distinct transducers and pathways. Emerging evidence demonstrates that allosteric modulators can induce biased pharmacology at the level of intrinsic agonism as well as through differential modulation of orthosteric agonist-signaling pathways. Here, we present key considerations in the discovery and development of mGlu5 allosteric modulators and the opportunities and pitfalls offered by biased agonism and modulation.
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25
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Borroto-Escuela DO, Tarakanov AO, Brito I, Fuxe K. Glutamate heteroreceptor complexes in the brain. Pharmacol Rep 2018; 70:936-950. [PMID: 32002960 DOI: 10.1016/j.pharep.2018.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/26/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
The existence of mGluR, NMDAR, AMPAR and putative KAR heteroreceptor complexes in synaptic and extrasynaptic regions of brain glutamate synapses represents a major integrative mechanism. Our aim in the current article is to analyze if the formation of the different types glutamate hetereceptor complexes involves the contribution of triplet amino acid homologies (protriplets) in a postulated receptor interface based on the triplet puzzle theory. Seven main sets (lists) of receptor pairs in databases were used containing various sets (lists) of human receptor heteromers and nonheteromers obtained from the available scientific publications including the publically available GPCR-hetnet database. Brain mGluR1-mGluR5 and mGluR2-mGluR4 isoreceptor complexes were demonstrated with a predominant extrasynaptic localization at a post- and prejunctional localization. The existence of putative mGluR4-mGluR7 heteroreceptor complexes in the basal ganglia is proposed. Metabotropic glutamate receptor subtypes also participated in the formation of a large number of heteroreceptor complexes like mGluR1-A1R, mGluR5-A2AR, mGluR5-D2R and D2R-A2AR-mGluR5, located in relation to glutamate synapses, especially in the basal ganglia. A putative mGluR1-GABAB1/2 heterocomplex may also exist. NMDAR heteroreceptor complexes were also demonstrated as a fundamental integrative mechanism in the glutamate synapse and its extrasynaptic membranes. It represented fundamental work on inter alia NMDAR-mGluR5, NMDAR-D1R and NMDAR-D2R heteroreceptor complexes involving both antagonistic and facilitatory allosteric receptor-receptor interactions. As to AMPA receptors, a heterocomplex was found for the interaction between IFNgR1 and the AMPAR mediated via the subunit GluA1 which may be of relevance for neuroinflammation. AMPAR-D2R heteroreceptor complexes were also demonstrated. Besides glutamate heteroreceptor complexes and their allosteric receptor-receptor interactions, a significant mechanism for the functional crosstalk can also be phosphorylation and/or reorganization of adapter proteins with dynamic binding to the two receptors modulating the allosteric receptor mechanism.
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Affiliation(s)
- Dasiel O Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, Urbino, Italy.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Alexander O Tarakanov
- St. Petersburg Institute for Informatics and Automation, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Ismel Brito
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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26
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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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27
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Di Menna L, Joffe ME, Iacovelli L, Orlando R, Lindsley CW, Mairesse J, Gressèns P, Cannella M, Caraci F, Copani A, Bruno V, Battaglia G, Conn PJ, Nicoletti F. Functional partnership between mGlu3 and mGlu5 metabotropic glutamate receptors in the central nervous system. Neuropharmacology 2017; 128:301-313. [PMID: 29079293 DOI: 10.1016/j.neuropharm.2017.10.026] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/09/2017] [Accepted: 10/21/2017] [Indexed: 12/19/2022]
Abstract
mGlu5 receptors are involved in mechanisms of activity-dependent synaptic plasticity, and are targeted by drugs developed for the treatment of CNS disorders. We report that mGlu3 receptors, which are traditionally linked to the control of neurotransmitter release, support mGlu5 receptor signaling in neurons and largely contribute to the robust mGlu5 receptor-mediated polyphosphoinositide hydrolysis in the early postnatal life. In cortical pyramidal neurons, mGlu3 receptor activation potentiated mGlu5 receptor-mediated somatic Ca2+ mobilization, and mGlu3 receptor-mediated long-term depression in the prefrontal cortex required the endogenous activation of mGlu5 receptors. The interaction between mGlu3 and mGlu5 receptors was also relevant to mechanisms of neuronal toxicity, with mGlu3 receptors shaping the influence of mGlu5 receptors on excitotoxic neuronal death. These findings shed new light into the complex role played by mGlu receptors in physiology and pathology, and suggest reconsideration of some of the current dogmas in the mGlu receptor field.
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Affiliation(s)
| | - Max E Joffe
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232-0697, USA
| | - Luisa Iacovelli
- Department of Physiology and Pharmacology, University Sapienza of Roma, 00185 Roma, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, University Sapienza of Roma, 00185 Roma, Italy
| | - Craig W Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232-0697, USA
| | - Jèrome Mairesse
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 1141 Paris, France
| | - Pierre Gressèns
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 1141 Paris, France; Centre for the Developing Brain, Department of Perinatal Health and Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London SE1 7EH, United Kingdom
| | | | - Filippo Caraci
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; I.R.C.C.S. Oasi Maria SS, 94018 Troina, Italy
| | - Agata Copani
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; Institute of Biostructure and Bioimaging, National Research Council, 95126 Catania, Italy
| | - Valeria Bruno
- I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy; Department of Physiology and Pharmacology, University Sapienza of Roma, 00185 Roma, Italy
| | | | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232-0697, USA
| | - Ferdinando Nicoletti
- I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy; Department of Physiology and Pharmacology, University Sapienza of Roma, 00185 Roma, Italy.
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28
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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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29
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Signalling assemblies: the odds of symmetry. Biochem Soc Trans 2017; 45:599-611. [PMID: 28620024 DOI: 10.1042/bst20170009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 02/06/2023]
Abstract
The assembly of proteins into complexes is fundamental to nearly all biological signalling processes. Symmetry is a dominant feature of the structures of experimentally determined protein complexes, observed in the vast majority of homomers and many heteromers. However, some asymmetric structures exist, and asymmetry also often forms transiently, intractable to traditional structure determination methods. Here, we explore the role of protein complex symmetry and asymmetry in cellular signalling, focusing on receptors, transcription factors and transmembrane channels, among other signalling assemblies. We highlight a recurrent tendency for asymmetry to be crucial for signalling function, often being associated with activated states. We conclude with a discussion of how consideration of protein complex symmetry and asymmetry has significant potential implications and applications for pharmacology and human disease.
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30
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31
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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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32
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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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33
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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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34
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Lundström L, Bissantz C, Beck J, Dellenbach M, Woltering TJ, Wichmann J, Gatti S. Reprint of Pharmacological and molecular characterization of the positive allosteric modulators of metabotropic glutamate receptor 2. Neuropharmacology 2017; 115:115-127. [PMID: 28216000 DOI: 10.1016/j.neuropharm.2016.08.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 10/20/2022]
Abstract
The metabotropic glutamate receptor 2 (mGlu2) plays an important role in the presynaptic control of glutamate release and several mGlu2 positive allosteric modulators (PAMs) have been under assessment for their potential as antipsychotics. The binding mode of mGlu2 PAMs is better characterized in functional terms while few data are available on the relationship between allosteric and orthosteric binding sites. Pharmacological studies characterizing binding and effects of two different chemical series of mGlu2 PAMs are therefore carried out here using the radiolabeled mGlu2 agonist 3[H]-LY354740 and mGlu2 PAM 3[H]-2,2,2-TEMPS. A multidimensional approach to the PAM mechanism of action shows that mGlu2 PAMs increase the affinity of 3[H]-LY354740 for the orthosteric site of mGlu2 as well as the number of 3[H]-LY354740 binding sites. 3[H]-2,2,2-TEMPS binding is also enhanced by the presence of LY354740. New residues in the allosteric rat mGlu2 binding pocket are identified to be crucial for the PAMs ligand binding, among these Tyr3.40 and Asn5.46. Also of remark, in the described experimental conditions S731A (Ser5.42) residue is important only for the mGlu2 PAM LY487379 and not for the compound PAM-1: an example of the structural differences among these mGlu2 PAMs. This study provides a summary of the information generated in the past decade on mGlu2 PAMs adding a detailed molecular investigation of PAM binding mode. Differences among mGlu2 PAM compounds are discussed as well as the mGlu2 regions interacting with mGlu2 PAM and NAM agents and residues driving mGlu2 PAM selectivity. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- L Lundström
- F. Hoffmann-La Roche AG, pRED, Pharma Research & Early Development, NORD Neuroscience, Switzerland
| | - C Bissantz
- Discovery Chemistry, Roche Innovation Center Basel, Grenzacherstrasse 124, Basel, CH4070, Switzerland
| | - J Beck
- F. Hoffmann-La Roche AG, pRED, Pharma Research & Early Development, NORD Neuroscience, Switzerland
| | - M Dellenbach
- F. Hoffmann-La Roche AG, pRED, Pharma Research & Early Development, NORD Neuroscience, Switzerland
| | - T J Woltering
- Discovery Chemistry, Roche Innovation Center Basel, Grenzacherstrasse 124, Basel, CH4070, Switzerland
| | - J Wichmann
- Discovery Chemistry, Roche Innovation Center Basel, Grenzacherstrasse 124, Basel, CH4070, Switzerland
| | - S Gatti
- F. Hoffmann-La Roche AG, pRED, Pharma Research & Early Development, NORD Neuroscience, Switzerland.
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35
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Leach K, Gregory KJ. Molecular insights into allosteric modulation of Class C G protein-coupled receptors. Pharmacol Res 2017; 116:105-118. [DOI: 10.1016/j.phrs.2016.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/18/2016] [Accepted: 12/07/2016] [Indexed: 12/23/2022]
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36
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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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37
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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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Lundström L, Bissantz C, Beck J, Dellenbach M, Woltering T, Wichmann J, Gatti S. Pharmacological and molecular characterization of the positive allosteric modulators of metabotropic glutamate receptor 2. Neuropharmacology 2016; 111:253-265. [DOI: 10.1016/j.neuropharm.2016.08.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 02/02/2023]
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Maillet EL, Cui M, Jiang P, Mezei M, Hecht E, Quijada J, Margolskee RF, Osman R, Max M. Characterization of the Binding Site of Aspartame in the Human Sweet Taste Receptor. Chem Senses 2016; 40:577-86. [PMID: 26377607 DOI: 10.1093/chemse/bjv045] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The sweet taste receptor, a heterodimeric G protein-coupled receptor comprised of T1R2 and T1R3, binds sugars, small molecule sweeteners, and sweet proteins to multiple binding sites. The dipeptide sweetener, aspartame binds in the Venus Flytrap Module (VFTM) of T1R2. We developed homology models of the open and closed forms of human T1R2 and human T1R3 VFTMs and their dimers and then docked aspartame into the closed form of T1R2's VFTM. To test and refine the predictions of our model, we mutated various T1R2 VFTM residues, assayed activity of the mutants and identified 11 critical residues (S40, Y103, D142, S144, S165, S168, Y215, D278, E302, D307, and R383) in and proximal to the binding pocket of the sweet taste receptor that are important for ligand recognition and activity of aspartame. Furthermore, we propose that binding is dependent on 2 water molecules situated in the ligand pocket that bridge 2 carbonyl groups of aspartame to residues D142 and L279. These results shed light on the activation mechanism and how signal transmission arising from the extracellular domain of the T1R2 monomer of the sweet receptor leads to the perception of sweet taste.
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Affiliation(s)
- Emeline L Maillet
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA
| | - Meng Cui
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1677, New York, NY 10029, USA and
| | - Peihua Jiang
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA, Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Mihaly Mezei
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1677, New York, NY 10029, USA and
| | - Elizabeth Hecht
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA
| | - Jeniffer Quijada
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA
| | - Robert F Margolskee
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA, Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Roman Osman
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1677, New York, NY 10029, USA and
| | - Marianna Max
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY 10029, USA, Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1677, New York, NY 10029, USA and
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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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Łukasiewicz S, Błasiak E, Szafran-Pilch K, Dziedzicka-Wasylewska M. Dopamine D2 and serotonin 5-HT1A receptor interaction in the context of the effects of antipsychotics - in vitro studies. J Neurochem 2016; 137:549-60. [PMID: 26876117 DOI: 10.1111/jnc.13582] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/11/2022]
Abstract
The serotonin 5-HT1A receptor (5-HT1 A R) and dopamine D2 receptor (D2 R) have been implicated as important sites of action in antipsychotics. Several lines of evidence indicate the key role of G protein-coupled receptors (GPCRs) heteromers in pathophysiology of schizophrenia and highlight these complexes as novel drug targets. Because heterodimers can form only on those cells co-expressing constituent receptors, they present a target of high pharmacological specificity in the context of biochemical effects induced by antipsychotic drugs. In studies conducted in the HEK 293 cell line, we demonstrated that 5-HT1 A R and D2 R are able to form constitutive heterodimers, and antipsychotic drugs (clozapine, olanzapine, aripiprazole, and lurasidone) enhanced this process, with clozapine being most effective. Various functional tests (cAMP and IP1 as well as ERK activation) indicated that the drugs had different effects on signal transduction by the heteromer. Interestingly, co-incubation of heterodimer-expressing HEK 293 cells with clozapine and the 5-HT1 A R agonist 8-OH DPAT potentiated post-synaptic effects, especially with respect to ERK activation. Our results indicate that the D2 -5-HT1A complex possesses biochemical, pharmacological, and functional properties distinct from those of mono- and homomers. This result has implications for the development of improved pharmacotherapy for schizophrenia or other disorders (activating the heteromer might be cognitive enhancing, since it is expressed in frontal cortex) through the specific targeting of heterodimers. We reported the constitutive formation of D2 -5-HT1A heteromers, which possess biochemical, pharmacological, and functional properties distinct from those of mono- and homomers, as revealed by antipsychotics action. We also showed that these two receptors are co-expressed in mouse cortical neurons; therefore their potential to heterodimerize may comprise an essential target for the development of novel strategies for schizophrenia treatment.
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Affiliation(s)
- Sylwia Łukasiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ewa Błasiak
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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42
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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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43
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Sengmany K, Gregory KJ. Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias. Br J Pharmacol 2015; 173:3001-17. [PMID: 26276909 DOI: 10.1111/bph.13281] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/30/2015] [Accepted: 07/26/2015] [Indexed: 12/12/2022] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGlu5 ) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR-based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine-tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus-bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- K Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - K J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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44
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Fatemi SH, Folsom TD. GABA receptor subunit distribution and FMRP-mGluR5 signaling abnormalities in the cerebellum of subjects with schizophrenia, mood disorders, and autism. Schizophr Res 2015; 167:42-56. [PMID: 25432637 PMCID: PMC5301472 DOI: 10.1016/j.schres.2014.10.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 12/24/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain. GABAergic receptor abnormalities have been documented in several major psychiatric disorders including schizophrenia, mood disorders, and autism. Abnormal expression of mRNA and protein for multiple GABA receptors has also been observed in multiple brain regions leading to alterations in the balance between excitatory/inhibitory signaling in the brain with potential profound consequences for normal cognition and maintenance of mood and perception. Altered expression of GABAA receptor subunits has been documented in fragile X mental retardation 1 (FMR1) knockout mice, suggesting that loss of its protein product, fragile X mental retardation protein (FMRP), impacts GABAA subunit expression. Recent postmortem studies from our laboratory have shown reduced expression of FMRP in the brains of subjects with schizophrenia, bipolar disorder, major depression, and autism. FMRP acts as a translational repressor and, under normal conditions, inhibits metabotropic glutamate receptor 5 (mGluR5)-mediated signaling. In fragile X syndrome (FXS), the absence of FMRP is hypothesized to lead to unregulated mGluR5 signaling, ultimately resulting in the behavioral and intellectual impairments associated with this disorder. Our laboratory has identified changes in mGluR5 expression in autism, schizophrenia, and mood disorders. In the current review article, we discuss our postmortem data on GABA receptors, FMRP, and mGluR5 levels and compare our results with other laboratories. Finally, we discuss the interactions between these molecules and the potential for new therapeutic interventions that target these interconnected signaling systems.
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Affiliation(s)
- S Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA; Department of Neuroscience, University of Minnesota Medical School, 321 Church St. SE, Minneapolis, MN 55455, USA.
| | - Timothy D Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA.
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45
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Ward RJ, Pediani JD, Godin AG, Milligan G. Regulation of oligomeric organization of the serotonin 5-hydroxytryptamine 2C (5-HT2C) receptor observed by spatial intensity distribution analysis. J Biol Chem 2015; 290:12844-57. [PMID: 25825490 PMCID: PMC4432300 DOI: 10.1074/jbc.m115.644724] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 12/19/2022] Open
Abstract
The questions of whether G protein-coupled receptors exist as monomers, dimers, and/or oligomers and if these species interconvert in a ligand-dependent manner are among the most contentious current issues in biology. When employing spatial intensity distribution analysis to laser scanning confocal microscope images of cells stably expressing either a plasma membrane-associated form of monomeric enhanced green fluorescent protein (eGFP) or a tandem version of this fluorophore, the eGFP tandem was identified as a dimer. Similar studies on cells stably expressing an eGFP-tagged form of the epidermal growth factor receptor demonstrated that, although largely a monomer in the basal state, this receptor rapidly became predominantly dimeric upon the addition of its ligand epidermal growth factor. In cells induced to express an eGFP-tagged form of the serotonin 5-hydroxytryptamine 2C (5-HT2C) receptor, global analysis of construct quantal brightness was consistent with the predominant form of the receptor being dimeric. However, detailed spatial intensity distribution analysis demonstrated the presence of multiple forms ranging from monomers to higher-order oligomers. Furthermore, treatment with chemically distinct 5-HT2C receptor antagonists resulted in a time-dependent change in the quaternary organization to one in which there was a preponderance of receptor monomers. This antagonist-mediated effect was reversible, because washout of the ligand resulted in the regeneration of many of the oligomeric forms of the receptor.
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Affiliation(s)
- Richard J Ward
- From the Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - John D Pediani
- From the Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Antoine G Godin
- the University of Bordeaux, LP2N, UMR 5298, F-33405 Talence, France, and the Institut d'Optique Graduate School and CNRS, LP2N, UMR 5298, F-33405 Talence, France
| | - Graeme Milligan
- From the Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom,
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46
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Gregory KJ, Conn PJ. Molecular Insights into Metabotropic Glutamate Receptor Allosteric Modulation. Mol Pharmacol 2015; 88:188-202. [PMID: 25808929 DOI: 10.1124/mol.114.097220] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/24/2015] [Indexed: 12/21/2022] Open
Abstract
The metabotropic glutamate (mGlu) receptors are a group of eight family C G protein-coupled receptors that are expressed throughout the central nervous system (CNS) and periphery. Within the CNS the different subtypes are found in neurons, both pre- and/or postsynaptically, where they mediate modulatory roles and in glial cells. The mGlu receptor family provides attractive targets for numerous psychiatric and neurologic disorders, with the majority of discovery programs focused on targeting allosteric sites, with allosteric ligands now available for all mGlu receptor subtypes. However, the development of allosteric ligands remains challenging. Biased modulation, probe dependence, and molecular switches all contribute to the complex molecular pharmacology exhibited by mGlu receptor allosteric ligands. In recent years we have made significant progress in our understanding of this molecular complexity coupled with an increased understanding of the structural basis of mGlu allosteric modulation.
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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 Vanderbilt Center for Neuroscience Drug Discovery & Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee (P.J.C)
| | - P Jeffrey Conn
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.); and Vanderbilt Center for Neuroscience Drug Discovery & Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee (P.J.C)
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47
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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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48
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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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49
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Kang HJ, Wilkins AD, Lichtarge O, Wensel TG. Determinants of endogenous ligand specificity divergence among metabotropic glutamate receptors. J Biol Chem 2014; 290:2870-8. [PMID: 25519912 DOI: 10.1074/jbc.m114.622233] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To determine the structural origins of diverse ligand response specificities among metabotropic glutamate receptors (mGluRs), we combined computational approaches with mutagenesis and ligand response assays to identify specificity-determining residues in the group I receptor, mGluR1, and the group III receptors, mGluR4 and mGluR7. Among these, mGluR1 responds to L-glutamate effectively, whereas it binds weakly to another endogenous ligand, L-serine-O-phosphate (L-SOP), which antagonizes the effects of L-glutamate. In contrast, mGluR4 has in common with other group III mGluR that it is activated with higher potency and efficacy by L-SOP. mGluR7 differs from mGluR4 and other group III mGluR in that L-glutamate and L-SOP activate it with low potency and efficacy. Enhanced versions of the evolutionary trace (ET) algorithm were used to identify residues that when swapped between mGluR1 and mGluR4 increased the potency of L-SOP inhibition relative to the potency of L-glutamate activation in mGluR1 mutants and others that diminished the potency/efficacy of L-SOP for mGluR4 mutants. In addition, combining ET identified swaps from mGluR4 with one identified by computational docking produced mGluR7 mutants that respond with dramatically enhanced potency/efficacy to L-SOP. These results reveal that an early functional divergence between group I/II and group III involved variation at positions primarily at allosteric sites located outside of binding pockets, whereas a later divergence within group III occurred through sequence variation both at the ligand-binding pocket and at loops near the dimerization interface and interlobe hinge region. They also demonstrate the power of ET for identifying allosteric determinants of evolutionary importance.
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Affiliation(s)
- Hye Jin Kang
- From the Graduate Program in Structural and Computational Biology and Molecular Biophysics
| | | | - Olivier Lichtarge
- From the Graduate Program in Structural and Computational Biology and Molecular Biophysics, the Department of Molecular and Human Genetics, and the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Theodore G Wensel
- From the Graduate Program in Structural and Computational Biology and Molecular Biophysics, the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
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Techlovská Š, Chambers JN, Dvořáková M, Petralia RS, Wang YX, Hájková A, Nová A, Franková D, Prezeau L, Blahos J. Metabotropic glutamate receptor 1 splice variants mGluR1a and mGluR1b combine in mGluR1a/b dimers in vivo. Neuropharmacology 2014; 86:329-336. [PMID: 25158311 DOI: 10.1016/j.neuropharm.2014.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 02/03/2023]
Abstract
The assembly of two covalently linked monomers into dimeric complexes is a prerequisite for metabotropic glutamate receptor 1 (mGluR1) function. The former concept of a strictly homodimeric subunit contribution in metabotropic glutamate receptor complexes has recently been brought into question. Alternative splicing of the GRM1 gene results in expression of variants that vary within their intracellular C-termini. Here we bring evidence that the short mGluR1b variant is found preferentially in a complex with the long mGluR1a variant in the rodent brain. The mGluR1a and mGluR1b variants distribution overlaps in Purkinje cells and the two variants colocalize in their spines. However mGluR1a and mGluR1b show distinct sub-cellular localization when expressed alone in neurons. We discovered that trafficking of mGluR1b to distal dendrites is reliant on its association with mGluR1a and that the long C-terminus of mGluR1a within the mGluR1a/b dimer is necessary for trafficking of the complex.
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Affiliation(s)
- Šárka Techlovská
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Jayne Nicole Chambers
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Michaela Dvořáková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Ronald S Petralia
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Ya-Xian Wang
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Alena Hájková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Alice Nová
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Daniela Franková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Laurent Prezeau
- CNRS UMR5203, Institut de génomique fonctionnelle, Montpellier, France.,INSERM U661, Montpellier, France.,Université Montpellier 1 & 2, Montpellier F-34000, France
| | - Jaroslav Blahos
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
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