1
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Stachowicz K. Interactions between metabotropic glutamate and CB1 receptors: implications for mood, cognition, and synaptic signaling based on data from mGluR and CB1R-targeting drugs. Pharmacol Rep 2024:10.1007/s43440-024-00612-6. [PMID: 38941064 DOI: 10.1007/s43440-024-00612-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 06/29/2024]
Abstract
Metabotropic glutamate receptors (mGluRs) are part of the G protein-coupled receptors (GPCRs) family. They are coupled to Gαq (group I) or Gi/o (groups II and III) proteins, which result in the generation of diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3) or the inhibition of adenylyl cyclase, respectively. mGluRs have been implicated in anxiety, depression, learning, and synaptic plasticity. Similarly, CB1 cannabinoid receptors (CB1Rs), also GPCRs, play roles in cognitive function and mood regulation through Gαi/o-mediated inhibition of adenylyl cyclase. Both mGluRs and CB1Rs exhibit surface labeling and undergo endocytosis. Given the similar cellular distribution and mechanisms of action, this review complies with fundamental data on the potential interactions and mutual regulation of mGluRs and CB1Rs in the context of depression, anxiety, and cognition, providing pioneering insights into their interplay.
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Affiliation(s)
- Katarzyna Stachowicz
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Kraków, 31-343, Poland.
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2
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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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3
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Gonzalez-Hernandez AJ, Munguba H, Levitz J. Emerging modes of regulation of neuromodulatory G protein-coupled receptors. Trends Neurosci 2024:S0166-2236(24)00088-2. [PMID: 38862331 DOI: 10.1016/j.tins.2024.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/13/2024]
Abstract
In the nervous system, G protein-coupled receptors (GPCRs) control neuronal excitability, synaptic transmission, synaptic plasticity, and, ultimately, behavior through spatiotemporally precise initiation of a variety of signaling pathways. However, despite their critical importance, there is incomplete understanding of how these receptors are regulated to tune their signaling to specific neurophysiological contexts. A deeper mechanistic picture of neuromodulatory GPCR function is needed to fully decipher their biological roles and effectively harness them for the treatment of neurological and psychiatric disorders. In this review, we highlight recent progress in identifying novel modes of regulation of neuromodulatory GPCRs, including G protein- and receptor-targeting mechanisms, receptor-receptor crosstalk, and unique features that emerge in the context of chemical synapses. These emerging principles of neuromodulatory GPCR tuning raise critical questions to be tackled at the molecular, cellular, synaptic, and neural circuit levels in the future.
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Affiliation(s)
| | - Hermany Munguba
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA; Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA; Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA.
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4
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Zhu X, Luo M, An K, Shi D, Hou T, Warshel A, Bai C. Exploring the activation mechanism of metabotropic glutamate receptor 2. Proc Natl Acad Sci U S A 2024; 121:e2401079121. [PMID: 38739800 PMCID: PMC11126994 DOI: 10.1073/pnas.2401079121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Homomeric dimerization of metabotropic glutamate receptors (mGlus) is essential for the modulation of their functions and represents a promising avenue for the development of novel therapeutic approaches to address central nervous system diseases. Yet, the scarcity of detailed molecular and energetic data on mGlu2 impedes our in-depth comprehension of their activation process. Here, we employ computational simulation methods to elucidate the activation process and key events associated with the mGlu2, including a detailed analysis of its conformational transitions, the binding of agonists, Gi protein coupling, and the guanosine diphosphate (GDP) release. Our results demonstrate that the activation of mGlu2 is a stepwise process and several energy barriers need to be overcome. Moreover, we also identify the rate-determining step of the mGlu2's transition from the agonist-bound state to its active state. From the perspective of free-energy analysis, we find that the conformational dynamics of mGlu2's subunit follow coupled rather than discrete, independent actions. Asymmetric dimerization is critical for receptor activation. Our calculation results are consistent with the observation of cross-linking and fluorescent-labeled blot experiments, thus illustrating the reliability of our calculations. Besides, we also identify potential key residues in the Gi protein binding position on mGlu2, mGlu2 dimer's TM6-TM6 interface, and Gi α5 helix by the change of energy barriers after mutation. The implications of our findings could lead to a more comprehensive grasp of class C G protein-coupled receptor activation.
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Affiliation(s)
- Xiaohong Zhu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei230026, People's Republic of China
| | - Mengqi Luo
- College of Management, Shenzhen University, Shenzhen518060, People's Republic of China
| | - Ke An
- Chenzhu (MoMeD) Biotechnology Co., Ltd, Hangzhou, Zhejiang310005, People's Republic of China
| | - Danfeng Shi
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei230026, People's Republic of China
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou310058, People's Republic of China
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, CA90089-1062
| | - Chen Bai
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong518172, People’s Republic of China
- Chenzhu (MoMeD) Biotechnology Co., Ltd, Hangzhou, Zhejiang310005, People's Republic of China
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5
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Parent HH, Niswender CM. Therapeutic Potential for Metabotropic Glutamate Receptor 7 Modulators in Cognitive Disorders. Mol Pharmacol 2024; 105:348-358. [PMID: 38423750 PMCID: PMC11026152 DOI: 10.1124/molpharm.124.000874] [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: 01/11/2024] [Revised: 02/05/2024] [Accepted: 02/12/2024] [Indexed: 03/02/2024] Open
Abstract
Metabotropic glutamate receptor 7 (mGlu7) is the most highly conserved and abundantly expressed mGlu receptor in the human brain. The presynaptic localization of mGlu7, coupled with its low affinity for its endogenous agonist, glutamate, are features that contribute to the receptor's role in modulating neuronal excitation and inhibition patterns, including long-term potentiation, in various brain regions. These characteristics suggest that mGlu7 modulation may serve as a novel therapeutic strategy in disorders of cognitive dysfunction, including neurodevelopmental disorders that cause impairments in learning, memory, and attention. Primary mutations in the GRM7 gene have recently been identified as novel causes of neurodevelopmental disorders, and these patients exhibit profound intellectual and cognitive disability. Pharmacological tools, such as agonists, antagonists, and allosteric modulators, have been the mainstay for targeting mGlu7 in its endogenous homodimeric form to probe effects of its function and modulation in disease models. However, recent research has identified diversity in dimerization, as well as trans-synaptic interacting proteins, that also play a role in mGlu7 signaling and pharmacological properties. These novel findings represent exciting opportunities in the field of mGlu receptor drug discovery and highlight the importance of further understanding the functions of mGlu7 in complex neurologic conditions at both the molecular and physiologic levels. SIGNIFICANCE STATEMENT: Proper expression and function of mGlu7 is essential for learning, attention, and memory formation at the molecular level within neural circuits. The pharmacological targeting of mGlu7 is undergoing a paradigm shift by incorporating an understanding of receptor interaction with other cis- and trans- acting synaptic proteins, as well as various intracellular signaling pathways. Based upon these new findings, mGlu7's potential as a drug target in the treatment of cognitive disorders and learning impairments is primed for exploration.
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Affiliation(s)
- Harrison H Parent
- Department of Pharmacology (H.H.P., C.M.N.), Warren Center for Neuroscience Drug Discovery (H.H.P., C.M.N.), Vanderbilt Brain Institute (C.M.N.), and Vanderbilt Institute for Chemical Biology (C.M.N.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
| | - Colleen M Niswender
- Department of Pharmacology (H.H.P., C.M.N.), Warren Center for Neuroscience Drug Discovery (H.H.P., C.M.N.), Vanderbilt Brain Institute (C.M.N.), and Vanderbilt Institute for Chemical Biology (C.M.N.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee (C.M.N.)
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6
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Casiraghi M, Wang H, Brennan P, Habrian C, Hubner H, Schmidt MF, Maul L, Pani B, Bahriz SM, Xu B, White E, Sunahara RK, Xiang YK, Lefkowitz RJ, Isacoff EY, Nucci N, Gmeiner P, Lerch M, Kobilka BK. Structure and dynamics determine G protein coupling specificity at a class A GPCR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587240. [PMID: 38586060 PMCID: PMC10996611 DOI: 10.1101/2024.03.28.587240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
G protein coupled receptors (GPCRs) exhibit varying degrees of selectivity for different G protein isoforms. Despite the abundant structures of GPCR-G protein complexes, little is known about the mechanism of G protein coupling specificity. The β2-adrenergic receptor is an example of GPCR with high selectivity for Gαs, the stimulatory G protein for adenylyl cyclase, and much weaker for the Gαi family of G proteins inhibiting adenylyl cyclase. By developing a new Gαi-biased agonist (LM189), we provide structural and biophysical evidence supporting that distinct conformations at ICL2 and TM6 are required for coupling of the different G protein subtypes Gαs and Gαi. These results deepen our understanding of G protein specificity and bias and can accelerate the design of ligands that select for preferred signaling pathways.
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7
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McCullock TW, Cardani LP, Kammermeier PJ. Signaling Specificity and Kinetics of the Human Metabotropic Glutamate Receptors. Mol Pharmacol 2024; 105:104-115. [PMID: 38164584 PMCID: PMC10794986 DOI: 10.1124/molpharm.123.000795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/13/2023] [Accepted: 11/08/2023] [Indexed: 01/03/2024] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a bioluminescence resonance energy transfer-based assay that detects the interaction between a split YFP-tagged Gβ 1γ2 and a Nanoluciferase tagged free Gβγ sensor, MAS-GRK3-ct- nanoluciferase with 14 specific Gα proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2 and 3 and 4, 6, 7, and 8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1 and 5) are known to couple to the Gq/11 family and generally thought to also couple to the pertussis toxin-sensitive Gi/o family some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all eight mGluRs through the Gi/o proteins and only mGluR1 and mGluR5 through Gq/11, and, perhaps surprisingly, not G14 None activated any Gs protein. Interestingly, coupling was seen with the group I and II but not the group III mGluRs to G16 Slow but significant coupling to Gz was also seen with the group II receptors. SIGNIFICANCE STATEMENT: Metabotropic glutamate receptor (mGluR)-G protein coupling has not been thoroughly examined, and some controversy remains about whether some mGluRs can activate Gαs family members. Here we examine the ability of each mGluR to activate representative members of every Gα protein family. While all mGluRs can activate Gαi/o proteins, only the group I mGluRs couple to Gαq/11, and no members of the family can activate Gαs family members, including the group I receptors alone or with positive allosteric modulators.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Loren P Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
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8
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Habrian C, Latorraca N, Fu Z, Isacoff EY. Homo- and hetero-dimeric subunit interactions set affinity and efficacy in metabotropic glutamate receptors. Nat Commun 2023; 14:8288. [PMID: 38092773 PMCID: PMC10719366 DOI: 10.1038/s41467-023-44013-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are dimeric class C G-protein-coupled receptors that operate in glia and neurons. Glutamate affinity and efficacy vary greatly between the eight mGluRs. The molecular basis of this diversity is not understood. We used single-molecule fluorescence energy transfer to monitor the structural rearrangements of activation in the mGluR ligand binding domain (LBD). In saturating glutamate, group II homodimers fully occupy the activated LBD conformation (full efficacy) but homodimers of group III mGluRs do not. Strikingly, the reduced efficacy of Group III homodimers does not arise from differences in the glutamate binding pocket but, instead, from interactions within the extracellular dimerization interface that impede active state occupancy. By contrast, the functionally boosted mGluR II/III heterodimers lack these interface 'brakes' to activation and heterodimer asymmetry in the flexibility of a disulfide loop connecting LBDs greatly favors occupancy of the activated conformation. Our results suggest that dimerization interface interactions generate substantial functional diversity by differentially stabilizing the activated conformation. This diversity may optimize mGluR responsiveness for the distinct spatio-temporal profiles of synaptic versus extrasynaptic glutamate.
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Affiliation(s)
- Chris Habrian
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Naomi Latorraca
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Zhu Fu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Ehud Y Isacoff
- Biophysics Graduate Group, University of California, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
- Weill Neurohub, University of California, Berkeley, CA, USA.
- Molecular Biology & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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9
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Lee J, Gonzalez-Hernandez AJ, Kristt M, Abreu N, Roßmann K, Arefin A, Marx DC, Broichhagen J, Levitz J. Distinct beta-arrestin coupling and intracellular trafficking of metabotropic glutamate receptor homo- and heterodimers. SCIENCE ADVANCES 2023; 9:eadi8076. [PMID: 38055809 PMCID: PMC10699790 DOI: 10.1126/sciadv.adi8076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
The metabotropic glutamate receptors (mGluRs) are family C, dimeric G protein-coupled receptors (GPCRs), which play critical roles in synaptic transmission. Despite an increasing appreciation of the molecular diversity of this family, how distinct mGluR subtypes are regulated remains poorly understood. We reveal that different group II/III mGluR subtypes show markedly different beta-arrestin (β-arr) coupling and endocytic trafficking. While mGluR2 is resistant to internalization and mGluR3 shows transient β-arr coupling, which enables endocytosis and recycling, mGluR8 and β-arr form stable complexes, which leads to efficient lysosomal targeting and degradation. Using chimeras and mutagenesis, we pinpoint carboxyl-terminal domain regions that control β-arr coupling and trafficking, including the identification of an mGluR8 splice variant with impaired internalization. We then use a battery of high-resolution fluorescence assays to find that heterodimerization further expands the diversity of mGluR regulation. Together, this work provides insight into the relationship between GPCR/β-arr complex formation and trafficking while revealing diversity and intricacy in the regulation of mGluRs.
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Affiliation(s)
- Joon Lee
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Melanie Kristt
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Nohely Abreu
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Kilian Roßmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Anisul Arefin
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Dagan C. Marx
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
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10
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Wang X, Wang M, Xu T, Feng Y, Shao Q, Han S, Chu X, Xu Y, Lin S, Zhao Q, Wu B. Structural insights into dimerization and activation of the mGlu2-mGlu3 and mGlu2-mGlu4 heterodimers. Cell Res 2023; 33:762-774. [PMID: 37286794 PMCID: PMC10543438 DOI: 10.1038/s41422-023-00830-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 05/14/2023] [Indexed: 06/09/2023] Open
Abstract
Heterodimerization of the metabotropic glutamate receptors (mGlus) has shown importance in the functional modulation of the receptors and offers potential drug targets for treating central nervous system diseases. However, due to a lack of molecular details of the mGlu heterodimers, understanding of the mechanisms underlying mGlu heterodimerization and activation is limited. Here we report twelve cryo-electron microscopy (cryo-EM) structures of the mGlu2-mGlu3 and mGlu2-mGlu4 heterodimers in different conformational states, including inactive, intermediate inactive, intermediate active and fully active conformations. These structures provide a full picture of conformational rearrangement of mGlu2-mGlu3 upon activation. The Venus flytrap domains undergo a sequential conformational change, while the transmembrane domains exhibit a substantial rearrangement from an inactive, symmetric dimer with diverse dimerization patterns to an active, asymmetric dimer in a conserved dimerization mode. Combined with functional data, these structures reveal that stability of the inactive conformations of the subunits and the subunit-G protein interaction pattern are determinants of asymmetric signal transduction of the heterodimers. Furthermore, a novel binding site for two mGlu4 positive allosteric modulators was observed in the asymmetric dimer interfaces of the mGlu2-mGlu4 heterodimer and mGlu4 homodimer, and may serve as a drug recognition site. These findings greatly extend our knowledge about signal transduction of the mGlus.
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Affiliation(s)
- Xinwei Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mu Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Tuo Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ye Feng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Qiang Shao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuo Han
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Xiaojing Chu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yechun Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Shuling Lin
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Qiang Zhao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- Zhongshan Institute of Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, Guangdong, China.
| | - Beili Wu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China.
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11
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McCullock TW, Cardani LP, Kammermeier PJ. Signaling specificity and kinetics of the human metabotropic glutamate receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550373. [PMID: 37546908 PMCID: PMC10402105 DOI: 10.1101/2023.07.24.550373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a BRET based assay that detects the interaction between a split YFP-tagged Gβ1γ2 and a Nanoluc tagged free Gβγ sensor, MAS-GRK3-ct-NLuc with 14 specific Ga proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2&3, and 4, 6, 7&8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1&5) are known to couple to the Gq/11 family, and generally thought to also couple to the PTX-sensitive Gi/o family; some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all 8 mGluRs through the Gi/o proteins, and only mGluR1&5 through Gq/11, and perhaps surprisingly, not G14. None activated any Gs protein. Interestingly, coupling was seen with the group I and II, but not the group III mGluRs to G16. Slow but significant coupling to Gz was also seen with the group II receptors.
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Affiliation(s)
- Tyler W. McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Loren P. Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Paul J. Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
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12
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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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13
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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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14
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Lecat-Guillet N, Quast RB, Liu H, Bourrier E, Møller TC, Rovira X, Soldevila S, Lamarque L, Trinquet E, Liu J, Pin JP, Rondard P, Margeat E. Concerted conformational changes control metabotropic glutamate receptor activity. SCIENCE ADVANCES 2023; 9:eadf1378. [PMID: 37267369 PMCID: PMC10413646 DOI: 10.1126/sciadv.adf1378] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 04/27/2023] [Indexed: 06/04/2023]
Abstract
Allosteric modulators bear great potential to fine-tune neurotransmitter action. Promising targets are metabotropic glutamate (mGlu) receptors, which are associated with numerous brain diseases. Orthosteric and allosteric ligands act in synergy to control the activity of these multidomain dimeric GPCRs. Here, we analyzed the effect of such molecules on the concerted conformational changes of full-length mGlu2 at the single-molecule level. We first established FRET sensors through genetic code expansion combined with click chemistry to monitor conformational changes on live cells. We then used single-molecule FRET and show that orthosteric agonist binding leads to the stabilization of most of the glutamate binding domains in their closed state, while the reorientation of the dimer into the active state remains partial. Allosteric modulators, interacting with the transmembrane domain, are required to stabilize the fully reoriented active dimer. These results illustrate how concerted conformational changes within multidomain proteins control their activity, and how these are modulated by allosteric ligands.
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Affiliation(s)
- Nathalie Lecat-Guillet
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Robert B. Quast
- Centre de Biologie Structurale (CBS), Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Hongkang Liu
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
- Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | | | - Thor C. Møller
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | | | | | - Eric Trinquet
- PerkinElmer Cisbio, Parc Marcel Boiteux, 30200 Codolet, France
| | - Jianfeng Liu
- Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), Univ. Montpellier, CNRS, INSERM, Montpellier, France
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15
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Saha S, González-Maeso J. The crosstalk between 5-HT 2AR and mGluR2 in schizophrenia. Neuropharmacology 2023; 230:109489. [PMID: 36889432 PMCID: PMC10103009 DOI: 10.1016/j.neuropharm.2023.109489] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/26/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Schizophrenia is a severe brain disorder that usually produces a lifetime of disability. First generation or typical antipsychotics such as haloperidol and second generation or atypical antipsychotics such as clozapine and risperidone remain the current standard for schizophrenia treatment. In some patients with schizophrenia, antipsychotics produce complete remission of positive symptoms, such as hallucinations and delusions. However, antipsychotic drugs are ineffective against cognitive deficits and indeed treated schizophrenia patients have small improvements or even deterioration in several cognitive domains. This underlines the need for novel and more efficient therapeutic targets for schizophrenia treatment. Serotonin and glutamate have been identified as key parts of two neurotransmitter systems involved in fundamental brain processes. Serotonin (or 5-hydroxytryptamine) 5-HT2A receptor (5-HT2AR) and metabotropic glutamate 2 receptor (mGluR2) are G protein-coupled receptors (GPCRs) that interact at epigenetic and functional levels. These two receptors can form GPCR heteromeric complexes through which their pharmacology, function and trafficking becomes affected. Here we review past and current research on the 5-HT2AR-mGluR2 heterocomplex and its potential implication in schizophrenia and antipsychotic drug action. This article is part of the Special Issue on "The receptor-receptor interaction as a new target for therapy".
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Affiliation(s)
- Somdatta Saha
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
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16
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Maslov I, Volkov O, Khorn P, Orekhov P, Gusach A, Kuzmichev P, Gerasimov A, Luginina A, Coucke Q, Bogorodskiy A, Gordeliy V, Wanninger S, Barth A, Mishin A, Hofkens J, Cherezov V, Gensch T, Hendrix J, Borshchevskiy V. Sub-millisecond conformational dynamics of the A 2A adenosine receptor revealed by single-molecule FRET. Commun Biol 2023; 6:362. [PMID: 37012383 PMCID: PMC10070357 DOI: 10.1038/s42003-023-04727-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 03/17/2023] [Indexed: 04/05/2023] Open
Abstract
The complex pharmacology of G-protein-coupled receptors (GPCRs) is defined by their multi-state conformational dynamics. Single-molecule Förster Resonance Energy Transfer (smFRET) is well suited to quantify dynamics for individual protein molecules; however, its application to GPCRs is challenging. Therefore, smFRET has been limited to studies of inter-receptor interactions in cellular membranes and receptors in detergent environments. Here, we performed smFRET experiments on functionally active human A2A adenosine receptor (A2AAR) molecules embedded in freely diffusing lipid nanodiscs to study their intramolecular conformational dynamics. We propose a dynamic model of A2AAR activation that involves a slow (>2 ms) exchange between the active-like and inactive-like conformations in both apo and antagonist-bound A2AAR, explaining the receptor's constitutive activity. For the agonist-bound A2AAR, we detected faster (390 ± 80 µs) ligand efficacy-dependent dynamics. Our work establishes a general smFRET platform for GPCR investigations that can potentially be used for drug screening and/or mechanism-of-action studies.
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Affiliation(s)
- Ivan Maslov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre, Biomedical Research Institute, Agoralaan C (BIOMED), Hasselt University, Diepenbeek, Belgium
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Leuven, Belgium
| | | | - Polina Khorn
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Philipp Orekhov
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Anastasiia Gusach
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Pavel Kuzmichev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Andrey Gerasimov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
- Vyatka State University, Kirov, Russia
| | - Aleksandra Luginina
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Quinten Coucke
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Leuven, Belgium
| | - Andrey Bogorodskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Valentin Gordeliy
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, Grenoble, France
| | - Simon Wanninger
- Physical Chemistry, Department of Chemistry, Center for Nano Science (CENS), Center for Integrated Protein Science (CIPSM) and Nanosystems Initiative München (NIM), Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Anders Barth
- Physical Chemistry, Department of Chemistry, Center for Nano Science (CENS), Center for Integrated Protein Science (CIPSM) and Nanosystems Initiative München (NIM), Ludwig-Maximilians-Universität Munich, Munich, Germany
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, HZ, Delft, The Netherlands
| | - Alexey Mishin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Leuven, Belgium
- Max Plank Institute for Polymer Research, Mainz, Germany
| | - Vadim Cherezov
- Bridge Institute, Department of Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Thomas Gensch
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Leuven, Belgium
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre, Biomedical Research Institute, Agoralaan C (BIOMED), Hasselt University, Diepenbeek, Belgium.
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Leuven, Belgium.
| | - Valentin Borshchevskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia.
- Joint Institute for Nuclear Research, Dubna, Russian Federation.
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17
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Freitas GA, Niswender CM. GRM7 gene mutations and consequences for neurodevelopment. Pharmacol Biochem Behav 2023; 225:173546. [PMID: 37003303 PMCID: PMC10192299 DOI: 10.1016/j.pbb.2023.173546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The metabotropic glutamate receptor 7 (mGlu7), encoded by the GRM7 gene in humans, is a presynaptic, G protein-coupled glutamate receptor that is essential for modulating neurotransmission. Mutations in or reduced expression of GRM7 have been identified in different genetic neurodevelopmental disorders (NDDs), and rare biallelic missense variants have been proposed to underlie a subset of NDDs. Clinical GRM7 variants have been associated with a range of symptoms consistent with neurodevelopmental molecular features, including hypomyelination, brain atrophy and defects in axon outgrowth. Here, we review the newest findings regarding the cellular and molecular defects caused by GRM7 variants in NDD patients.
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Affiliation(s)
- Geanne A Freitas
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America.
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18
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Krishna Kumar K, O'Brien ES, Habrian CH, Latorraca NR, Wang H, Tuneew I, Montabana E, Marqusee S, Hilger D, Isacoff EY, Mathiesen JM, Kobilka BK. Negative allosteric modulation of the glucagon receptor by RAMP2. Cell 2023; 186:1465-1477.e18. [PMID: 37001505 PMCID: PMC10144504 DOI: 10.1016/j.cell.2023.02.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/23/2023] [Accepted: 02/17/2023] [Indexed: 04/03/2023]
Abstract
Receptor activity-modifying proteins (RAMPs) modulate the activity of many Family B GPCRs. We show that RAMP2 directly interacts with the glucagon receptor (GCGR), a Family B GPCR responsible for blood sugar homeostasis, and broadly inhibits receptor-induced downstream signaling. HDX-MS experiments demonstrate that RAMP2 enhances local flexibility in select locations in and near the receptor extracellular domain (ECD) and in the 6th transmembrane helix, whereas smFRET experiments show that this ECD disorder results in the inhibition of active and intermediate states of the intracellular surface. We determined the cryo-EM structure of the GCGR-Gs complex at 2.9 Å resolution in the presence of RAMP2. RAMP2 apparently does not interact with GCGR in an ordered manner; however, the receptor ECD is indeed largely disordered along with rearrangements of several intracellular hallmarks of activation. Our studies suggest that RAMP2 acts as a negative allosteric modulator of GCGR by enhancing conformational sampling of the ECD.
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Affiliation(s)
- Kaavya Krishna Kumar
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Evan S O'Brien
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Chris H Habrian
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Naomi R Latorraca
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Inga Tuneew
- Zealand Pharma A/S, Sydmarken 11, Soborg 2860, Denmark
| | - Elizabeth Montabana
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Susan Marqusee
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA; QB3 Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley CA 94720, USA; Department of Chemistry, University of California, Berkeley, Berkeley CA 94720, USA
| | - Daniel Hilger
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marbacher Weg 6, Marburg 35037, Germany
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley CA 94720, USA
| | | | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA.
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19
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Huh E, Agosto MA, Wensel TG, Lichtarge O. Coevolutionary signals in metabotropic glutamate receptors capture residue contacts and long-range functional interactions. J Biol Chem 2023; 299:103030. [PMID: 36806686 PMCID: PMC10060750 DOI: 10.1016/j.jbc.2023.103030] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023] Open
Abstract
Upon ligand binding to a G protein-coupled receptor, extracellular signals are transmitted into a cell through sets of residue interactions that translate ligand binding into structural rearrangements. These interactions needed for functions impose evolutionary constraints so that, on occasion, mutations in one position may be compensated by other mutations at functionally coupled positions. To quantify the impact of amino acid substitutions in the context of major evolutionary divergence in the G protein-coupled receptor subfamily of metabotropic glutamate receptors (mGluRs), we combined two phylogenetic-based algorithms, Evolutionary Trace and covariation Evolutionary Trace, to infer potential structure-function couplings and roles in mGluRs. We found a subset of evolutionarily important residues at known functional sites and evidence of coupling among distinct structural clusters in mGluR. In addition, experimental mutagenesis and functional assays confirmed that some highly covariant residues are coupled, revealing their synergy. Collectively, these findings inform a critical step toward understanding the molecular and structural basis of amino acid variation patterns within mGluRs and provide insight for drug development, protein engineering, and analysis of naturally occurring variants.
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Affiliation(s)
- Eunna Huh
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA; Retina and Optic Nerve Research Laboratory, Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Olivier Lichtarge
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.
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20
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Koda S, Hu J, Ju X, Sun G, Shao S, Tang RX, Zheng KY, Yan J. The role of glutamate receptors in the regulation of the tumor microenvironment. Front Immunol 2023; 14:1123841. [PMID: 36817470 PMCID: PMC9929049 DOI: 10.3389/fimmu.2023.1123841] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
Glutamate, as one of the most important carbon sources in the TCA cycle, is central in metabolic processes that will subsequently influence tumor progression. Several factors can affect the expression of glutamate receptors, playing either a tumor-promoting or tumor-suppressor role in cancer. Thus, the activation of glutamate receptors by the ligand could play a role in tumor development as ample studies have demonstrated the expression of glutamate receptors in a broad range of tumor cells. Glutamate and its receptors are involved in the regulation of different immune cells' development and function, as suggested by the receptor expression in immune cells. The activation of glutamate receptors can enhance the effectiveness of the effector's T cells, or decrease the cytokine production in immunosuppressive myeloid-derived suppressor cells, increasing the antitumor immune response. These receptors are essential for the interaction between tumor and immune cells within the tumor microenvironment (TME) and the regulation of antitumor immune responses. Although the role of glutamate in the TCA cycle has been well studied, few studies have deeply investigated the role of glutamate receptors in the regulation of cancer and immune cells within the TME. Here, by a systematic review of the available data, we will critically assess the physiopathological relevance of glutamate receptors in the regulation of cancer and immune cells in the TME and provide some unifying hypotheses for futures research on the role of glutamate receptors in the immune modulation of the tumor.
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Affiliation(s)
- Stephane Koda
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jing Hu
- Department of Bioinformatics, School of Life Science, Xuzhou Medical University, Xuzhou, Jiangsu, China,Department of Genetics, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Xiaoman Ju
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Guowei Sun
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Simin Shao
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Ren-Xian Tang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Kui-Yang Zheng
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China,*Correspondence: Juming Yan, ; Kui-Yang Zheng,
| | - Juming Yan
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, National Experimental Demonstration Center for Basic Medicine Education, Xuzhou Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, Jiangsu, China,*Correspondence: Juming Yan, ; Kui-Yang Zheng,
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21
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Kinetic fingerprinting of metabotropic glutamate receptors. Commun Biol 2023; 6:104. [PMID: 36707695 PMCID: PMC9883448 DOI: 10.1038/s42003-023-04468-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 01/12/2023] [Indexed: 01/28/2023] Open
Abstract
Dimeric metabotropic glutamate receptors (mGluRs) are abundantly expressed in neurons. In mammals, eight subunit isoforms, mGluR1-8, have been identified, forming the groups I, II, and III. We investigated receptor dimerization and kinetics of these mGluR isoforms in excised membrane patches by FRET and confocal patch-clamp fluorometry. We show that 5 out of 8 homodimeric receptors develop characteristic glutamate-induced on- and off-kinetics, as do 11 out of 28 heterodimers. Glutamate-responsive heterodimers were identified within each group, between groups I and II as well as between groups II and III, but not between groups I and III. The glutamate-responsive heterodimers showed heterogeneous activation and deactivation kinetics. Interestingly, mGluR7, not generating a kinetic response in homodimers, showed fast on-kinetics in mGluR2/7 and mGluR3/7 while off-kinetics retained the speed of mGluR2 or mGluR3 respectively. In conclusion, glutamate-induced conformational changes in heterodimers appear within each group and between groups if one group II subunit is present.
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22
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The role of thalamic group II mGlu receptors in health and disease. Neuronal Signal 2022; 6:NS20210058. [PMID: 36561092 PMCID: PMC9760452 DOI: 10.1042/ns20210058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 12/25/2022] Open
Abstract
The thalamus plays a pivotal role in the integration and processing of sensory, motor, and cognitive information. It is therefore important to understand how the thalamus operates in states of both health and disease. In the present review, we discuss the function of the Group II metabotropic glutamate (mGlu) receptors within thalamic circuitry, and how they may represent therapeutic targets in treating disease states associated with thalamic dysfunction.
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23
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Reed CW, Rodriguez AL, Kalbfleisch JJ, Seto M, Jenkins MT, Blobaum AL, Chang S, Lindsley CW, Niswender CM. Development and profiling of mGlu 7 NAMs with a range of saturable inhibition of agonist responses in vitro. Bioorg Med Chem Lett 2022; 74:128923. [PMID: 35944850 PMCID: PMC10015594 DOI: 10.1016/j.bmcl.2022.128923] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 11/02/2022]
Abstract
We describe here a series of metabotropic glutamate receptor 7 (mGlu7) negative allosteric modulators (NAMs) with a saturable range of activity in inhibiting responses to an orthosteric agonist in two distinct in vitro pharmacological assays. The range of inhibition among compounds in this scaffold provides highly structurally related ligands with differential degrees of receptor blockade that can be used to understand inhibitory efficacy profiles in native tissue or in vivo.
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Affiliation(s)
- Carson W Reed
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Alice L Rodriguez
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Jacob J Kalbfleisch
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Mabel Seto
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Matthew T Jenkins
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Anna L Blobaum
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Sichen Chang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States.
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24
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Ma X, Guo J, Fu Y, Shen C, Jiang P, Zhang Y, Zhang L, Yu Y, Fan J, Chai R. G protein-coupled receptors in cochlea: Potential therapeutic targets for hearing loss. Front Mol Neurosci 2022; 15:1028125. [PMID: 36311029 PMCID: PMC9596917 DOI: 10.3389/fnmol.2022.1028125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
The prevalence of hearing loss-related diseases caused by different factors is increasing worldwide year by year. Currently, however, the patient’s hearing loss has not been effectively improved. Therefore, there is an urgent need to adopt new treatment measures and treatment techniques to help improve the therapeutic effect of hearing loss. G protein-coupled receptors (GPCRs), as crucial cell surface receptors, can widely participate in different physiological and pathological processes, particularly play an essential role in many disease occurrences and be served as promising therapeutic targets. However, no specific drugs on the market have been found to target the GPCRs of the cochlea. Interestingly, many recent studies have demonstrated that GPCRs can participate in various pathogenic process related to hearing loss in the cochlea including heredity, noise, ototoxic drugs, cochlear structure, and so on. In this review, we comprehensively summarize the functions of 53 GPCRs known in the cochlea and their relationships with hearing loss, and highlight the recent advances of new techniques used in cochlear study including cryo-EM, AI, GPCR drug screening, gene therapy vectors, and CRISPR editing technology, as well as discuss in depth the future direction of novel GPCR-based drug development and gene therapy for cochlear hearing loss. Collectively, this review is to facilitate basic and (pre-) clinical research in this area, and provide beneficial help for emerging GPCR-based cochlear therapies.
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Affiliation(s)
- Xiangyu Ma
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Jiamin Guo
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yaoyang Fu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cangsong Shen
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yuan Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
- Research Institute of Otolaryngology, Nanjing, China
| | - Lei Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, China
| | - Yafeng Yu
- First Affiliated Hospital of Soochow University, Soochow, China
- *Correspondence: Yafeng Yu,
| | - Jiangang Fan
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Jiangang Fan,
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
- Renjie Chai,
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25
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Lin X, Fisher NM, Dogra S, Senter RK, Reed CW, Kalbfleisch JJ, Lindsley CW, Asher WB, Xiang Z, Niswender CM, Javitch JA. Differential activity of mGlu 7 allosteric modulators provides evidence for mGlu 7/8 heterodimers at hippocampal Schaffer collateral-CA1 synapses. J Biol Chem 2022; 298:102458. [PMID: 36063995 PMCID: PMC9531177 DOI: 10.1016/j.jbc.2022.102458] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/25/2022] Open
Abstract
Glutamate acts at eight metabotropic glutamate (mGlu) receptor subtypes expressed in a partially overlapping fashion in distinct brain circuits. Recent evidence indicates that specific mGlu receptor protomers can heterodimerize and that these heterodimers can exhibit different pharmacology when compared to their homodimeric counterparts. Group III mGlu agonist-induced suppression of evoked excitatory potentials and induction of long-term potentiation at Schaffer collateral-CA1 (SC-CA1) synapses in the rodent hippocampus can be blocked by the selective mGlu7 negative allosteric modulator (NAM), ADX71743. Curiously, a different mGlu7 NAM, 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazonolo[4,5-c]pyridin-4(5H)-one, failed to block these responses in brain slices despite its robust activity at mGlu7 homodimers in vitro. We hypothesized that this might result from heterodimerization of mGlu7 with another mGlu receptor protomer and focused on mGlu8 as a candidate given the reported effects of mGlu8-targeted compounds in the hippocampus. Here, we used complemented donor acceptor-resonance energy transfer to study mGlu7/8 heterodimer activation in vitro and observed that ADX71743 blocked responses of both mGlu7/7 homodimers and mGlu7/8 heterodimers, whereas 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazonolo[4,5-c]pyridin-4(5H)-one only antagonized responses of mGlu7/7 homodimers. Taken together with our electrophysiology observations, these results suggest that a receptor with pharmacology consistent with an mGlu7/8 heterodimer modulates the activity of SC-CA1 synapses. Building on this hypothesis, we identified two additional structurally related mGlu7 NAMs that also differ in their activity at mGlu7/8 heterodimers, in a manner consistent with their ability to inhibit synaptic transmission and plasticity at SC-CA1. Thus, we propose that mGlu7/8 heterodimers are a key molecular target for modulating the activity of hippocampal SC-CA1 synapses.
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Affiliation(s)
- Xin Lin
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Nicole M Fisher
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Shalini Dogra
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Rebecca K Senter
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Carson W Reed
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Jacob J Kalbfleisch
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Wesley B Asher
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
| | - Jonathan A Javitch
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA; Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA.
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26
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Berry MH, Holt A, Broichhagen J, Donthamsetti P, Flannery JG, Isacoff EY. Photopharmacology for vision restoration. Curr Opin Pharmacol 2022; 65:102259. [PMID: 35749908 DOI: 10.1016/j.coph.2022.102259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/03/2022]
Abstract
Blinding diseases that are caused by degeneration of rod and cone photoreceptor cells often spare the rest of the retinal circuit, from bipolar cells, which are directly innervated by photoreceptor cells, to the output ganglion cells that project axons to the brain. A strategy for restoring vision is to introduce light sensitivity to the surviving cells of the retina. One approach is optogenetics, in which surviving cells are virally transfected with a gene encoding a signaling protein that becomes sensitive to light by binding to the biologically available chromophore retinal, the same chromophore that is used by the opsin photo-detectors of rods and cones. A second approach uses photopharmacology, in which a synthetic photoswitch associates with a native or engineered ion channel or receptor. We review these approaches and look ahead to the next generation of advances that could reconstitute core aspects of natural vision.
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Affiliation(s)
- Michael H Berry
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Amy Holt
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | | | - Prashant Donthamsetti
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - John G Flannery
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720, USA; Vision Science, Herbert Wertheim School of Optometry, University of California, Berkeley, CA, 94720, USA
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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27
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Ojima K, Kakegawa W, Yamasaki T, Miura Y, Itoh M, Michibata Y, Kubota R, Doura T, Miura E, Nonaka H, Mizuno S, Takahashi S, Yuzaki M, Hamachi I, Kiyonaka S. Coordination chemogenetics for activation of GPCR-type glutamate receptors in brain tissue. Nat Commun 2022; 13:3167. [PMID: 35710788 PMCID: PMC9203742 DOI: 10.1038/s41467-022-30828-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 05/19/2022] [Indexed: 11/20/2022] Open
Abstract
Direct activation of cell-surface receptors is highly desirable for elucidating their physiological roles. A potential approach for cell-type-specific activation of a receptor subtype is chemogenetics, in which both point mutagenesis of the receptors and designed ligands are used. However, ligand-binding properties are affected in most cases. Here, we developed a chemogenetic method for direct activation of metabotropic glutamate receptor 1 (mGlu1), which plays essential roles in cerebellar functions in the brain. Our screening identified a mGlu1 mutant, mGlu1(N264H), that was activated directly by palladium complexes. A palladium complex showing low cytotoxicity successfully activated mGlu1 in mGlu1(N264H) knock-in mice, revealing that activation of endogenous mGlu1 is sufficient to evoke the critical cellular mechanism of synaptic plasticity, a basis of motor learning in the cerebellum. Moreover, cell-type-specific activation of mGlu1 was demonstrated successfully using adeno-associated viruses in mice, which shows the potential utility of this chemogenetics for clarifying the physiological roles of mGlu1 in a cell-type-specific manner. Cell-type-specific activation of receptors is desirable for elucidating their roles in tissues or animals. Here, the authors developed a chemogenetic method for direct activation of mGlu1, a GPCR-type glutamate receptor subtype, and demonstrate its use in mouse brain tissue.
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Affiliation(s)
- Kento Ojima
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan.,Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Wataru Kakegawa
- Department of Neurophysiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Tokiwa Yamasaki
- Department of Neurophysiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Yuta Miura
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Masayuki Itoh
- Department of Neurophysiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Yukiko Michibata
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Tomohiro Doura
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Eriko Miura
- Department of Neurophysiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Hiroshi Nonaka
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center in Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8575, Japan
| | - Satoru Takahashi
- Laboratory Animal Resource Center in Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8575, Japan
| | - Michisuke Yuzaki
- Department of Neurophysiology, Keio University School of Medicine, Tokyo, 160-8582, Japan.
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan.
| | - Shigeki Kiyonaka
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan. .,Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, 464-8603, Japan.
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28
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Metabotropic Glutamate Receptors at Ribbon Synapses in the Retina and Cochlea. Cells 2022; 11:cells11071097. [PMID: 35406660 PMCID: PMC8998116 DOI: 10.3390/cells11071097] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 02/01/2023] Open
Abstract
Our senses define our view of the world. They allow us to adapt to environmental stimuli and are essential for communication and social behaviour. For most humans, seeing and hearing are central senses for their daily life. Our eyes and ears respond to an extraordinary broad range of stimuli covering about 12 log units of light intensity or acoustic power, respectively. The cellular basis is represented by sensory cells (photoreceptors in the retina and inner hair cells in the cochlea) that convert sensory inputs into electrical signals. Photoreceptors and inner hair cells have developed a specific pre-synaptic structure, termed synaptic ribbon, that is decorated with numerous vesicles filled with the excitatory neurotransmitter glutamate. At these ribbon synapses, glutamatergic signal transduction is guided by distinct sets of metabotropic glutamate receptors (mGluRs). MGluRs belong to group II and III of the receptor classification can inhibit neuronal activity, thus protecting neurons from overstimulation and subsequent degeneration. Consequently, dysfunction of mGluRs is associated with vision and hearing disorders. In this review, we introduce the principle characteristics of ribbon synapses and describe group II and III mGluRs in these fascinating structures in the retina and cochlea.
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29
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Advances in tethered photopharmacology for precise optical control of signaling proteins. Curr Opin Pharmacol 2022; 63:102196. [PMID: 35245800 DOI: 10.1016/j.coph.2022.102196] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 12/25/2022]
Abstract
To overcome the limitations of traditional pharmacology, the field of photopharmacology has developed around the central concept of using light to endow drug action with spatiotemporal precision. Tethered photopharmacology, where a photoswitchable ligand is covalently attached to a target protein, offers a particularly high degree of spatiotemporal control, as well as the ability to genetically target drug action and limit effects to specific protein subtypes. In this review, we describe the core engineering concepts of tethered pharmacology and highlight recent advances in harnessing the power of tethered photopharmacology for an expanded palette of targets and conjugation modes using new, complementary strategies. We also discuss the various applications, including mechanistic studies from the molecular biophysical realm to in vivo studies in behaving animals, that demonstrate the power of tethered pharmacology.
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30
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Acher FC, Cabayé A, Eshak F, Goupil-Lamy A, Pin JP. Metabotropic glutamate receptor orthosteric ligands and their binding sites. Neuropharmacology 2022; 204:108886. [PMID: 34813860 DOI: 10.1016/j.neuropharm.2021.108886] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 12/21/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) have been discovered almost four decades ago. Since then, their pharmacology has been largely developed as well as their structural organization. Indeed mGluRs are attractive therapeutic targets for numerous psychiatric and neurological disorders because of their modulating role of synaptic transmission. The more recent drug discovery programs have mostly concentrated on allosteric modulators. However, orthosteric agonists and antagonists have remained unavoidable pharmacological tools as, although not expected, many of them can reach the brain, or can be modified to reach the brain. This review focuses on the most common orthosteric ligands as well as on the few allosteric modulators interacting with the glutamate binding domain. The 3D-structures of these ligands at their binding sites are reported. For most of them, X-Ray structures or docked homology models are available. Because of the high conservation of the binding site, subtype selective agonists were not easy to find. Yet, some were discovered when extending their chemical structures in order to reach selective sites of the receptors.
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Affiliation(s)
- Francine C Acher
- Faculty of Basic and Biomedical Sciences, University of Paris, CNRS, 75270 Paris Cedex 06, France.
| | - Alexandre Cabayé
- Faculty of Basic and Biomedical Sciences, University of Paris, CNRS, 75270 Paris Cedex 06, France; BIOVIA, Dassault Systèmes, F-78140 Vélizy-Villacoublay Cedex, France
| | - Floriane Eshak
- Faculty of Basic and Biomedical Sciences, University of Paris, CNRS, 75270 Paris Cedex 06, France
| | - Anne Goupil-Lamy
- BIOVIA, Dassault Systèmes, F-78140 Vélizy-Villacoublay Cedex, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, 34094 Montpellier Cedex 5, France
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31
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Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
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32
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McCullock TW, Kammermeier PJ. The evidence for and consequences of metabotropic glutamate receptor heterodimerization. Neuropharmacology 2021; 199:108801. [PMID: 34547332 DOI: 10.1016/j.neuropharm.2021.108801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 09/07/2021] [Accepted: 09/17/2021] [Indexed: 12/15/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are an essential component of the mammalian central nervous system. These receptors modulate neuronal excitability in response to extracellular glutamate through the activation of intracellular heterotrimeric G proteins. Like most other class C G protein-coupled receptors, mGluRs function as obligate dimer proteins, meaning they need to form dimer complexes before becoming functional receptors. All mGluRs possess the ability to homodimerize, but studies over the past ten years have demonstrated these receptors are also capable of forming heterodimers in specific patterns. These mGluR heterodimers appear to have their own unique biophysical behavior and pharmacology with both native and synthetic compounds with few rules having been identified that allow for prediction of the consequences of any particular mGluR pair forming heterodimers. Here, we review the relevant literature demonstrating the existence and consequences of mGluR heterodimerization. By collecting biophysical and pharmacological data of several mGluR heterodimers we demonstrate the lack of generalizable behavior of these complexes indicating that each individual dimeric pair needs to be investigated independently. Additionally, by combining sequence alignment and structural analysis, we propose that interactions between the β4-A Helix Loop and the D Helix in the extracellular domain of these receptors are the structural components that dictate heterodimerization compatibility. Finally, we discuss the potential implications of mGluR heterodimerization from the viewpoints of further developing our understanding of neuronal physiology and leveraging mGluRs as a therapeutic target for the treatment of pathophysiology.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
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Klotz L, Enz R. MGluR7 is a presynaptic metabotropic glutamate receptor at ribbon synapses of inner hair cells. FASEB J 2021; 35:e21855. [PMID: 34644430 DOI: 10.1096/fj.202100672r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/15/2021] [Accepted: 07/29/2021] [Indexed: 01/17/2023]
Abstract
Glutamate is the most pivotal excitatory neurotransmitter in the central nervous system. Metabotropic glutamate receptors (mGluRs) dimerize and can couple to inhibitory intracellular signal cascades, thereby protecting glutamatergic neurons from excessive excitation and cell death. MGluR7 is correlated with age-related hearing deficits and noise-induced hearing loss; however its exact localization in the cochlea is unknown. Here, we analyzed the expression and localization of mGluR7a and mGluR7b in mouse cochlear wholemounts in detail, using confocal microscopy and 3D reconstructions. We observed a presynaptic localization of mGluR7a at inner hair cells (IHCs), close to the synaptic ribbon. To detect mGluR7b, newly generated antibodies were characterized and showed co-localization with mGluR7a at IHC ribbon synapses. Compared to the number of synaptic ribbons, the numbers of mGluR7a and mGluR7b puncta were reduced at higher frequencies (48 to 64 kHz) and in older animals (6 and 12 months). Previously, we reported a presynaptic localization of mGluR4 and mGluR8b at this synapse type. This enables the possibility for the formation of homo- and/or heterodimeric receptors composed of mGluR4, mGluR7a, mGluR7b and mGluR8b at IHC ribbon synapses. These receptor complexes might represent new molecular targets suited for pharmacological concepts to protect the cochlea against noxious stimuli and excitotoxicity.
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Affiliation(s)
- Lisa Klotz
- Institute for Biochemistry, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Ralf Enz
- Institute for Biochemistry, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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34
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Hofmann CS, Carrington S, Keller AN, Gregory KJ, Niswender CM. Regulation and functional consequences of mGlu 4 RNA editing. RNA (NEW YORK, N.Y.) 2021; 27:1220-1240. [PMID: 34244459 PMCID: PMC8457003 DOI: 10.1261/rna.078729.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/01/2021] [Indexed: 06/13/2023]
Abstract
Metabotropic glutamate receptor 4 (mGlu4) is one of eight mGlu receptors within the Class C G protein-coupled receptor superfamily. mGlu4 is primarily localized to the presynaptic membrane of neurons where it functions as an auto and heteroreceptor controlling synaptic release of neurotransmitter. mGlu4 is implicated in numerous disorders and is a promising drug target; however, more remains to be understood about its regulation and pharmacology. Using high-throughput sequencing, we have validated and quantified an adenosine-to-inosine (A-to-I) RNA editing event that converts glutamine 124 to arginine in mGlu4; additionally, we have identified a rare but novel K129R site. Using an in vitro editing assay, we then validated the pre-mRNA duplex that allows for editing by ADAR enzymes and predicted its conservation across the mammalian species. Structural modeling of the mGlu4 protein predicts the Q124R substitution to occur in the B helix of the receptor that is critical for receptor dimerization and activation. Interestingly, editing of a receptor homodimer does not disrupt G protein activation in response to the endogenous agonist, glutamate. Using an assay designed to specifically measure heterodimer populations at the surface, however, we found that Q124R substitution decreased the propensity of mGlu4 to heterodimerize with mGlu2 and mGlu7 Our study is the first to extensively describe the extent and regulatory factors of RNA editing of mGlu4 mRNA transcripts. In addition, we have proposed a novel functional consequence of this editing event that provides insights regarding its effects in vivo and expands the regulatory capacity for mGlu receptors.
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MESH Headings
- Adenosine Deaminase/genetics
- Adenosine Deaminase/metabolism
- Amino Acid Sequence
- Animals
- Base Pairing
- Base Sequence
- Birds
- Cerebral Cortex/cytology
- Cerebral Cortex/metabolism
- Corpus Striatum/cytology
- Corpus Striatum/metabolism
- HEK293 Cells
- Hippocampus/cytology
- Hippocampus/metabolism
- Humans
- Models, Molecular
- Neurons/cytology
- Neurons/metabolism
- Nucleic Acid Conformation
- Point Mutation
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- RNA Editing
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Receptors, Metabotropic Glutamate/metabolism
- Reptiles
- Sequence Homology, Amino Acid
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Affiliation(s)
- Christopher S Hofmann
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Sheridan Carrington
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Andrew N Keller
- Department of Pharmacology and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Karen J Gregory
- Department of Pharmacology and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, USA
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37203, USA
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35
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Allosteric modulators enhance agonist efficacy by increasing the residence time of a GPCR in the active state. Nat Commun 2021; 12:5426. [PMID: 34521824 PMCID: PMC8440590 DOI: 10.1038/s41467-021-25620-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 08/20/2021] [Indexed: 01/17/2023] Open
Abstract
Much hope in drug development comes from the discovery of positive allosteric modulators (PAM) that display target subtype selectivity and act by increasing agonist potency and efficacy. How such compounds can allosterically influence agonist action remains unclear. Metabotropic glutamate receptors (mGlu) are G protein-coupled receptors that represent promising targets for brain diseases, and for which PAMs acting in the transmembrane domain have been developed. Here, we explore the effect of a PAM on the structural dynamics of mGlu2 in optimized detergent micelles using single molecule FRET at submillisecond timescales. We show that glutamate only partially stabilizes the extracellular domains in the active state. Full activation is only observed in the presence of a PAM or the Gi protein. Our results provide important insights on the role of allosteric modulators in mGlu activation, by stabilizing the active state of a receptor that is otherwise rapidly oscillating between active and inactive states. Here, the authors use smFRET to assess the structural dynamics of metabotropic glutamate receptor mGlu2 and show that a positive allosteric modulator or the Gi protein stabilize mGlu2 in the glutamate-induced active state, leading to the full activation of the receptor.
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36
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Structures of human mGlu2 and mGlu7 homo- and heterodimers. Nature 2021; 594:589-593. [PMID: 34135509 DOI: 10.1038/s41586-021-03641-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 05/13/2021] [Indexed: 12/16/2022]
Abstract
The metabotropic glutamate receptors (mGlus) are involved in the modulation of synaptic transmission and neuronal excitability in the central nervous system1. These receptors probably exist as both homo- and heterodimers that have unique pharmacological and functional properties2-4. Here we report four cryo-electron microscopy structures of the human mGlu subtypes mGlu2 and mGlu7, including inactive mGlu2 and mGlu7 homodimers; mGlu2 homodimer bound to an agonist and a positive allosteric modulator; and inactive mGlu2-mGlu7 heterodimer. We observed a subtype-dependent dimerization mode for these mGlus, as a unique dimer interface that is mediated by helix IV (and that is important for limiting receptor activity) exists only in the inactive mGlu2 structure. The structures provide molecular details of the inter- and intra-subunit conformational changes that are required for receptor activation, which distinguish class C G-protein-coupled receptors from those in classes A and B. Furthermore, our structure and functional studies of the mGlu2-mGlu7 heterodimer suggest that the mGlu7 subunit has a dominant role in controlling dimeric association and G-protein activation in the heterodimer. These insights into mGlu homo- and heterodimers highlight the complex landscape of mGlu dimerization and activation.
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37
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Defining the Homo- and Heterodimerization Propensities of Metabotropic Glutamate Receptors. Cell Rep 2021; 31:107605. [PMID: 32375054 PMCID: PMC7271767 DOI: 10.1016/j.celrep.2020.107605] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/10/2020] [Accepted: 04/10/2020] [Indexed: 01/02/2023] Open
Abstract
The eight metabotropic glutamate receptors (mGluRs) serve critical modulatory roles throughout the nervous system. The molecular diversity of mGluRs is thought to be further expanded by the formation of heterodimers, but the co-expression of mGluR subtypes at the cellular level and the relative propensities of heterodimer formation are not well known. Here, we analyze single-cell RNA sequencing data and find that cortical pyramidal cells express multiple mGluR subtypes with distinct profiles for different receptor combinations. We then develop quantitative, fluorescence-based assays to define the relative homo- and heterodimer propensities across group-I, -II, and -III mGluRs. We find a strong preference for heterodimerization in a number of cases, including mGluR2 with mGluR3, which we confirm in frontal cortex using in situ RNA hybridization and co-immunoprecipitation. Together, our findings support the biological relevance of mGluR heterodimerization and highlight the complex landscape of mGluR populations in the brain.
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38
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Yang Z, Xu H, Wang J, Chen W, Zhao M. Single-Molecule Fluorescence Techniques for Membrane Protein Dynamics Analysis. APPLIED SPECTROSCOPY 2021; 75:491-505. [PMID: 33825543 DOI: 10.1177/00037028211009973] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fluorescence-based single-molecule techniques, mainly including fluorescence correlation spectroscopy (FCS) and single-molecule fluorescence resonance energy transfer (smFRET), are able to analyze the conformational dynamics and diversity of biological macromolecules. They have been applied to analysis of the dynamics of membrane proteins, such as membrane receptors and membrane transport proteins, due to their superior ability in resolving spatio-temporal heterogeneity and the demand of trace amounts of analytes. In this review, we first introduced the basic principle involved in FCS and smFRET. Then we summarized the labeling and immobilization strategies of membrane protein molecules, the confocal-based and TIRF-based instrumental configuration, and the data processing methods. The applications to membrane protein dynamics analysis are described in detail with the focus on how to select suitable fluorophores, labeling sites, experimental setup, and analysis methods. In the last part, the remaining challenges to be addressed and further development in this field are also briefly discussed.
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Affiliation(s)
- Ziyu Yang
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, 12465 Peking University, Beijing, China
| | - Haiqi Xu
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, 12465 Peking University, Beijing, China
| | - Jiayu Wang
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, 12465 Peking University, Beijing, China
| | - Wei Chen
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, 12465 Peking University, Beijing, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, 12465 Peking University, Beijing, China
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39
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Thibado JK, Tano JY, Lee J, Salas-Estrada L, Provasi D, Strauss A, Marcelo Lamim Ribeiro J, Xiang G, Broichhagen J, Filizola M, Lohse MJ, Levitz J. Differences in interactions between transmembrane domains tune the activation of metabotropic glutamate receptors. eLife 2021; 10:e67027. [PMID: 33880992 PMCID: PMC8102066 DOI: 10.7554/elife.67027] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/19/2021] [Indexed: 12/16/2022] Open
Abstract
The metabotropic glutamate receptors (mGluRs) form a family of neuromodulatory G-protein-coupled receptors that contain both a seven-helix transmembrane domain (TMD) and a large extracellular ligand-binding domain (LBD) which enables stable dimerization. Although numerous studies have revealed variability across subtypes in the initial activation steps at the level of LBD dimers, an understanding of inter-TMD interaction and rearrangement remains limited. Here, we use a combination of single molecule fluorescence, molecular dynamics, functional assays, and conformational sensors to reveal that distinct TMD assembly properties drive differences between mGluR subtypes. We uncover a variable region within transmembrane helix 4 (TM4) that contributes to homo- and heterodimerization in a subtype-specific manner and tunes orthosteric, allosteric, and basal activation. We also confirm a critical role for a conserved inter-TM6 interface in stabilizing the active state during orthosteric or allosteric activation. Together this study shows that inter-TMD assembly and dynamic rearrangement drive mGluR function with distinct properties between subtypes.
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Affiliation(s)
- Jordana K Thibado
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical SciencesNew YorkUnited States
| | | | - Joon Lee
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
| | - Leslie Salas-Estrada
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Davide Provasi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Alexa Strauss
- Tri-Institutional PhD Program in Chemical BiologyNew YorkUnited States
| | | | - Guoqing Xiang
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
| | | | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Martin J Lohse
- Max Delbrück Center for Molecular MedicineBerlinGermany
- ISAR Bioscience InstitutePlanegg-MunichGermany
| | - Joshua Levitz
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical SciencesNew YorkUnited States
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
- Tri-Institutional PhD Program in Chemical BiologyNew YorkUnited States
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40
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De Sa Nogueira D, Bourdy R, Filliol D, Quessada C, McCort-Tranchepain I, Acher F, Zwiller J, Romieu P, Befort K. LSP2-9166, an orthosteric mGlu4 and mGlu7 receptor agonist, reduces cocaine self-administration under a progressive ratio schedule in rats. Neurosci Lett 2020; 764:135603. [PMID: 33387661 DOI: 10.1016/j.neulet.2020.135603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/18/2020] [Accepted: 12/23/2020] [Indexed: 11/24/2022]
Abstract
Cocaine addiction is a serious health issue in Western countries. Despite the regular increase in cocaine consumption across the population, there is no specific treatment for cocaine addiction. Critical roles for glutamate neurotransmission in the rewarding effects of psychostimulants as well as relapse have been suggested and accumulating evidence indicates that targeting mGlu group III receptors could represent a promising strategy to develop therapeutic compounds to treat addiction. In this context, the aim of our study was to examine the effect of LSP2-9166, a mGlu4/mGlu7 receptor orthosteric agonist, on the motivation for cocaine intake. We used an intravenous self-administration paradigm in male Wistar rats as a reliable model of voluntary drug intake. We first evaluated the direct impact of cocaine on Grm4 and Grm7 gene expression. Voluntary cocaine intake under a fixed ratio schedule of injections induced an increase of both mGlu4 and mGlu7 receptor transcripts in nucleus accumbens and hippocampus. We then evaluated the ability of LSP2-9166 to affect cocaine self-administration under a progressive ratio schedule of reinforcement. We found that this compound inhibits the motivation to obtain the drug, although it induced a hypolocomotor effect which could biais motivation index. Our findings demonstrate that mGlu group III receptors represent new targets for decreasing motivation to self-administer cocaine.
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Affiliation(s)
- David De Sa Nogueira
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France
| | - Romain Bourdy
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France
| | - Dominique Filliol
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France
| | - Cyril Quessada
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France; Université de Strasbourg, Inserm, UMR-S1118, 11 rue Humann, F-67000, Strasbourg, France
| | - Isabelle McCort-Tranchepain
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, CNRS UMR8601, Université de Paris 45 rue des Saints-Pères, F-75270, Paris Cedex 6, France
| | - Francine Acher
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, CNRS UMR8601, Université de Paris 45 rue des Saints-Pères, F-75270, Paris Cedex 6, France
| | - Jean Zwiller
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France
| | - Pascal Romieu
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France
| | - Katia Befort
- Université de Strasbourg, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, UMR 7364, CNRS 12 rue Goethe, F-67000, Strasbourg, France.
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41
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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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42
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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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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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Durham RJ, Latham DR, Sanabria H, Jayaraman V. Structural Dynamics of Glutamate Signaling Systems by smFRET. Biophys J 2020; 119:1929-1936. [PMID: 33096078 PMCID: PMC7732771 DOI: 10.1016/j.bpj.2020.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a powerful technique for investigating the structural dynamics of biological macromolecules. smFRET reveals the conformational landscape and dynamic changes of proteins by building on the static structures found using cryo-electron microscopy, x-ray crystallography, and other methods. Combining smFRET with static structures allows for a direct correlation between dynamic conformation and function. Here, we discuss the different experimental setups, fluorescence detection schemes, and data analysis strategies that enable the study of structural dynamics of glutamate signaling across various timescales. We illustrate the versatility of smFRET by highlighting studies of a wide range of questions, including the mechanism of activation and transport, the role of intrinsically disordered segments, and allostery and cooperativity between subunits in biological systems responsible for glutamate signaling.
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Affiliation(s)
- Ryan J Durham
- University of Texas Health Science Center at Houston, Houston, Texas
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45
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Capturing Peptide-GPCR Interactions and Their Dynamics. Molecules 2020; 25:molecules25204724. [PMID: 33076289 PMCID: PMC7587574 DOI: 10.3390/molecules25204724] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022] Open
Abstract
Many biological functions of peptides are mediated through G protein-coupled receptors (GPCRs). Upon ligand binding, GPCRs undergo conformational changes that facilitate the binding and activation of multiple effectors. GPCRs regulate nearly all physiological processes and are a favorite pharmacological target. In particular, drugs are sought after that elicit the recruitment of selected effectors only (biased ligands). Understanding how ligands bind to GPCRs and which conformational changes they induce is a fundamental step toward the development of more efficient and specific drugs. Moreover, it is emerging that the dynamic of the ligand–receptor interaction contributes to the specificity of both ligand recognition and effector recruitment, an aspect that is missing in structural snapshots from crystallography. We describe here biochemical and biophysical techniques to address ligand–receptor interactions in their structural and dynamic aspects, which include mutagenesis, crosslinking, spectroscopic techniques, and mass-spectrometry profiling. With a main focus on peptide receptors, we present methods to unveil the ligand–receptor contact interface and methods that address conformational changes both in the ligand and the GPCR. The presented studies highlight a wide structural heterogeneity among peptide receptors, reveal distinct structural changes occurring during ligand binding and a surprisingly high dynamics of the ligand–GPCR complexes.
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46
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Bacic L, Sabantsev A, Deindl S. Recent advances in single-molecule fluorescence microscopy render structural biology dynamic. Curr Opin Struct Biol 2020; 65:61-68. [PMID: 32634693 DOI: 10.1016/j.sbi.2020.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/21/2020] [Accepted: 05/21/2020] [Indexed: 01/30/2023]
Abstract
Single-molecule fluorescence microscopy has long been appreciated as a powerful tool to study the structural dynamics that enable biological function of macromolecules. Recent years have witnessed the development of more complex single-molecule fluorescence techniques as well as powerful combinations with structural approaches to obtain mechanistic insights into the workings of various molecular machines and protein complexes. In this review, we highlight these developments that together bring us one step closer to a dynamic understanding of biological processes in atomic details.
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Affiliation(s)
- Luka Bacic
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Anton Sabantsev
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| | - Sebastian Deindl
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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Srivastava A, Das B, Yao AY, Yan R. Metabotropic Glutamate Receptors in Alzheimer's Disease Synaptic Dysfunction: Therapeutic Opportunities and Hope for the Future. J Alzheimers Dis 2020; 78:1345-1361. [PMID: 33325389 PMCID: PMC8439550 DOI: 10.3233/jad-201146] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the presence of neuritic plaques and neurofibrillary tangles. The impaired synaptic plasticity and dendritic loss at the synaptic level is an early event associated with the AD pathogenesis. The abnormal accumulation of soluble oligomeric amyloid-β (Aβ), the major toxic component in amyloid plaques, is viewed to trigger synaptic dysfunctions through binding to several presynaptic and postsynaptic partners and thus to disrupt synaptic transmission. Over time, the abnormalities in neural transmission will result in cognitive deficits, which are commonly manifested as memory loss in AD patients. Synaptic plasticity is regulated through glutamate transmission, which is mediated by various glutamate receptors. Here we review recent progresses in the study of metabotropic glutamate receptors (mGluRs) in AD cognition. We will discuss the role of mGluRs in synaptic plasticity and their modulation as a possible strategy for AD cognitive improvement.
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Affiliation(s)
- Akriti Srivastava
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
| | - Brati Das
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
| | - Annie Y. Yao
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
| | - Riqiang Yan
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
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