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Ma S, Yin X, Pin JP, Rondard P, Yi P, Liu J. Absence of calcium-sensing receptor basal activity due to inter-subunit disulfide bridges. Commun Biol 2024; 7:501. [PMID: 38664468 PMCID: PMC11045811 DOI: 10.1038/s42003-024-06189-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
G protein-coupled receptors naturally oscillate between inactive and active states, often resulting in receptor constitutive activity with important physiological consequences. Among the class C G protein-coupled receptors that typically sense amino-acids and their derivatives, the calcium sensing receptor (CaSR) tightly controls blood calcium levels. Its constitutive activity has not yet been studied. Here, we demonstrate the importance of the inter-subunit disulfide bridges in maintaining the inactive state of CaSR, resulting in undetectable constitutive activity, unlike the other class C receptors. Deletion of these disulfide bridges results in strong constitutive activity that is abolished by mutations preventing amino acid binding. It shows that this inter-subunit disulfide link is necessary to limit the agonist effect of amino acids on CaSR. Furthermore, human genetic mutations deleting these bridges and associated with hypocalcemia result in elevated CaSR constitutive activity. These results highlight the physiological importance of fine tuning the constitutive activity of G protein-coupled receptors.
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Affiliation(s)
- Shumin Ma
- 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, Hubei, China
| | - Xueliang Yin
- 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, Hubei, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, Cedex 5, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, Cedex 5, France.
| | - Ping Yi
- 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, Hubei, 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, Hubei, China.
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2
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Shimohata A, Rai D, Akagi T, Usui S, Ogiwara I, Kaneda M. The intracellular C-terminal domain of mGluR6 contains ER retention motifs. Mol Cell Neurosci 2023; 126:103875. [PMID: 37352898 DOI: 10.1016/j.mcn.2023.103875] [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: 03/20/2023] [Revised: 06/15/2023] [Accepted: 06/19/2023] [Indexed: 06/25/2023] Open
Abstract
Metabotropic glutamate receptor 6 (mGluR6) predominantly localizes to the postsynaptic sites of retinal ON-bipolar cells, at which it recognizes glutamate released from photoreceptors. The C-terminal domain (CTD) of mGluR6 contains a cluster of basic amino acids resembling motifs for endoplasmic reticulum (ER) retention. We herein investigated whether these basic residues are involved in regulating the subcellular localization of mGluR6 in 293T cells expressing mGluR6 CTD mutants using immunocytochemistry, immunoprecipitation, and flow cytometry. We showed that full-length mGluR6 localized to the ER and cell surface, whereas mGluR6 mutants with 15- and 20-amino acid deletions from the C terminus localized to the ER, but were deficient at the cell surface. We also demonstrated that the cell surface deficiency of mGluR6 mutants was rescued by introducing an alanine substitution at basic residues within the CTD. The surface-deficient mGluR6 mutant still did not localize to the cell surface and was retained in the ER when co-expressed with surface-expressible constructs, including full-length mGluR6, even though surface-deficient and surface-expressible constructs formed heteromeric complexes. The co-expression of the surface-deficient mGluR6 mutant reduced the surface levels of surface-expressible constructs. These results indicate that basic residues in the mGluR6 CTD served as ER retention signals. We suggest that exposed ER retention motifs in the aberrant assembly containing truncated or misfolded mGluR6 prevent these protein complexes from being transported to the cell surface.
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Affiliation(s)
- Atsushi Shimohata
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Dilip Rai
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Takumi Akagi
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Sumiko Usui
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Ikuo Ogiwara
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan.
| | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
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3
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Strauss A, Gonzalez-Hernandez AJ, Lee J, Abreu N, Selvakumar P, Salas-Estrada L, Kristt M, Marx DC, Gilliland K, Melancon BJ, Filizola M, Meyerson J, Levitz J. Structural basis of allosteric modulation of metabotropic glutamate receptor activation and desensitization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.13.552748. [PMID: 37645747 PMCID: PMC10461995 DOI: 10.1101/2023.08.13.552748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The metabotropic glutamate receptors (mGluRs) are neuromodulatory family C G protein coupled receptors which assemble as dimers and allosterically couple extracellular ligand binding domains (LBDs) to transmembrane domains (TMDs) to drive intracellular signaling. Pharmacologically, mGluRs can be targeted either at the LBDs by glutamate and synthetic orthosteric compounds or at the TMDs by allosteric modulators. Despite the potential of allosteric TMD-targeting compounds as therapeutics, an understanding of the functional and structural basis of their effects on mGluRs is limited. Here we use a battery of approaches to dissect the distinct functional and structural effects of orthosteric versus allosteric ligands. We find using electrophysiological and live cell imaging assays that both agonists and positive allosteric modulators (PAMs) can drive activation and desensitization of mGluRs. The effects of PAMs are pleiotropic, including both the ability to boost the maximal response to orthosteric agonists and to serve independently as desensitization-biased agonists across mGluR subtypes. Conformational sensors reveal PAM-driven inter-subunit re-arrangements at both the LBD and TMD. Motivated by this, we determine cryo-electron microscopy structures of mGluR3 in the presence of either an agonist or antagonist alone or in combination with a PAM. These structures reveal PAM-driven re-shaping of intra- and inter-subunit conformations and provide evidence for a rolling TMD dimer interface activation pathway that controls G protein and beta-arrestin coupling. Highlights -Agonists and PAMs drive mGluR activation, desensitization, and endocytosis-PAMs are desensitization-biased and synergistic with agonists-Four combinatorial ligand conditions reveal an ensemble of full-length mGluR structures with novel interfaces-Activation and desensitization involve rolling TMD interfaces which are re-shaped by PAM.
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4
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Caniceiro AB, Bueschbell B, Schiedel AC, Moreira IS. Class A and C GPCR Dimers in Neurodegenerative Diseases. Curr Neuropharmacol 2022; 20:2081-2141. [PMID: 35339177 PMCID: PMC9886835 DOI: 10.2174/1570159x20666220327221830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 02/21/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.
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Affiliation(s)
- Ana B. Caniceiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Beatriz Bueschbell
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Irina S. Moreira
- University of Coimbra, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; ,Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal,Address correspondence to this author at the Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal; E-mail:
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5
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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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6
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Azam S, Jakaria M, Kim J, Ahn J, Kim IS, Choi DK. Group I mGluRs in Therapy and Diagnosis of Parkinson’s Disease: Focus on mGluR5 Subtype. Biomedicines 2022; 10:biomedicines10040864. [PMID: 35453614 PMCID: PMC9032558 DOI: 10.3390/biomedicines10040864] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 11/16/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs; members of class C G-protein-coupled receptors) have been shown to modulate excitatory neurotransmission, regulate presynaptic extracellular glutamate levels, and modulate postsynaptic ion channels on dendritic spines. mGluRs were found to activate myriad signalling pathways to regulate synapse formation, long-term potentiation, autophagy, apoptosis, necroptosis, and pro-inflammatory cytokines release. A notorious expression pattern of mGluRs has been evident in several neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and schizophrenia. Among the several mGluRs, mGluR5 is one of the most investigated types of considered prospective therapeutic targets and potential diagnostic tools in neurodegenerative diseases and neuropsychiatric disorders. Recent research showed mGluR5 radioligands could be a potential tool to assess neurodegenerative disease progression and trace respective drugs’ kinetic properties. This article provides insight into the group I mGluRs, specifically mGluR5, in the progression and possible therapy for PD.
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Affiliation(s)
- Shofiul Azam
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Korea; (S.A.); (M.J.); (J.K.); (J.A.)
| | - Md. Jakaria
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Korea; (S.A.); (M.J.); (J.K.); (J.A.)
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
| | - JoonSoo Kim
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Korea; (S.A.); (M.J.); (J.K.); (J.A.)
| | - Jaeyong Ahn
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Korea; (S.A.); (M.J.); (J.K.); (J.A.)
| | - In-Su Kim
- Department of Biotechnology, College of Biomedical and Health Science, Research Institute of Inflammatory Disease (RID), Konkuk University, Chungju 27478, Korea
- Correspondence: (I.-S.K.); (D.-K.C.); Tel.: +82-43-840-3905 (I.-S.K.); +82-43-840-3610 (D.-K.C.); Fax: +82-43-840-3872 (D.-K.C.)
| | - Dong-Kug Choi
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Korea; (S.A.); (M.J.); (J.K.); (J.A.)
- Department of Biotechnology, College of Biomedical and Health Science, Research Institute of Inflammatory Disease (RID), Konkuk University, Chungju 27478, Korea
- Correspondence: (I.-S.K.); (D.-K.C.); Tel.: +82-43-840-3905 (I.-S.K.); +82-43-840-3610 (D.-K.C.); Fax: +82-43-840-3872 (D.-K.C.)
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7
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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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8
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Senoo A, Yamada Y, Ojima K, Doura T, Hamachi I, Kiyonaka S. Orthogonal Activation of Metabotropic Glutamate Receptor Using Coordination Chemogenetics. Front Chem 2022; 9:825669. [PMID: 35096780 PMCID: PMC8795677 DOI: 10.3389/fchem.2021.825669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/28/2021] [Indexed: 12/01/2022] Open
Abstract
Cell-surface receptors play a pivotal role as transducers of extracellular input. Although different cell types express the same receptor, the physiological roles of the receptor are highly dependent on cell type. To understand each role, tactics for cell-specific activation of the target receptor are in high demand. Herein, we developed an orthogonal activation method targeting metabotropic glutamate receptor 1 (mGlu1), a G-protein coupled receptor. In this method, direct activation via coordination-based chemogenetics (dA-CBC) was adopted, where activation of mGlu1 was artificially induced by a protein conformational change in response to the coordination of a metal ion or metal-ion complex. Our structure-based protein design and screening approach identified mGlu1 mutants that were directly activated by the coordination of Cu2+ or Zn2+, in addition to our previous Pd-complex-sensitive mGlu1 mutant. Notably, the activation of the mutants was mutually orthogonal, resulting in cell-type selective activation in a model system using HEK293 cells.
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Affiliation(s)
- Akinobu Senoo
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Yutaro Yamada
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Kento Ojima
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Tomohiro Doura
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
- ERATO (Exploratory Research for Advanced Technology, JST), Tokyo, Japan
| | - Shigeki Kiyonaka
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
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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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Jang J, Kim SK, Guthrie B, Goddard WA. Synergic Effects in the Activation of the Sweet Receptor GPCR Heterodimer for Various Sweeteners Predicted Using Molecular Metadynamics Simulations. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:12250-12261. [PMID: 34613740 DOI: 10.1021/acs.jafc.1c03779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The sweet taste is elicited by activation of the TAS1R2/1R3 heterodimer G protein-coupled receptor. This is a therapeutic target for treatment of obesity and metabolic dysfunctions. Sweetener blends provide attractive strategies to lower the sugar level while preserving the attractive taste of food. To understand the synergic effect of various sweetener blend combinations of artificial and natural sweeteners, we carried out our molecular dynamics studies using predicted structures of the TAS1R2/1R3 heterodimer and predicted structures for the sweeteners. We used as a measure of activation the intracellular ionic lock distance between transmembrane helices 3 and 6 of TAS1R3. We find that full synergic combinations [rebaudioside A (Reb-A)/acesulfame K and Reb-A/sucralose] and partial synergic combinations (sucralose/acesulfame K) show significantly more negative changes in the free energy compared to single-ligand cases, while a pair known to be suppressive (saccharin and acesulfame K) shows significantly less changes than for the single-ligand case. This study provides an atomistic understanding of the mechanism for synergy and identifies new combinations of sweeteners to reduce the caloric content for treating diseases.
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Affiliation(s)
- Jaewan Jang
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Soo-Kyung Kim
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Brian Guthrie
- Cargill Global Core Research, Wayzata, Minnesota 55391, United States
| | - William A Goddard
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
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11
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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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12
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Chen X, Wang L, Cui Q, Ding Z, Han L, Kou Y, Zhang W, Wang H, Jia X, Dai M, Shi Z, Li Y, Li X, Geng Y. Structural insights into the activation of human calcium-sensing receptor. eLife 2021; 10:68578. [PMID: 34467854 PMCID: PMC8476121 DOI: 10.7554/elife.68578] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/31/2021] [Indexed: 12/16/2022] Open
Abstract
Human calcium-sensing receptor (CaSR) is a G-protein-coupled receptor that maintains Ca2+ homeostasis in serum. Here, we present the cryo-electron microscopy structures of the CaSR in the inactive and agonist+PAM bound states. Complemented with previously reported structures of CaSR, we show that in addition to the full inactive and active states, there are multiple intermediate states during the activation of CaSR. We used a negative allosteric nanobody to stabilize the CaSR in the fully inactive state and found a new binding site for Ca2+ ion that acts as a composite agonist with L-amino acid to stabilize the closure of active Venus flytraps. Our data show that agonist binding leads to compaction of the dimer, proximity of the cysteine-rich domains, large-scale transitions of seven-transmembrane domains, and inter- and intrasubunit conformational changes of seven-transmembrane domains to accommodate downstream transducers. Our results reveal the structural basis for activation mechanisms of CaSR and clarify the mode of action of Ca2+ ions and L-amino acid leading to the activation of the receptor.
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Affiliation(s)
- Xiaochen Chen
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lu Wang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qianqian Cui
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zhanyu Ding
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Li Han
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yongjun Kou
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenqing Zhang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Haonan Wang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaomin Jia
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Mei Dai
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zhenzhong Shi
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yuying Li
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiyang Li
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yong Geng
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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13
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Cation-π Interactions and their Functional Roles in Membrane Proteins. J Mol Biol 2021; 433:167035. [PMID: 33957146 PMCID: PMC8338773 DOI: 10.1016/j.jmb.2021.167035] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 01/25/2023]
Abstract
Cation-π interactions arise as a result of strong attractive forces between positively charged entities and the π-electron cloud of aromatic groups. The physicochemical characteristics of cation-π interactions are particularly well-suited to the dual hydrophobic/hydrophilic environment of membrane proteins. As high-resolution structural data of membrane proteins bring molecular features into increasingly sharper view, cation-π interactions are gaining traction as essential contributors to membrane protein chemistry, function, and pharmacology. Here we review the physicochemical properties of cation-π interactions and present several prominent examples which demonstrate significant roles for this specialized biological chemistry.
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14
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15
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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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16
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Zhou Y, Meng J, Xu C, Liu J. Multiple GPCR Functional Assays Based on Resonance Energy Transfer Sensors. Front Cell Dev Biol 2021; 9:611443. [PMID: 34041234 PMCID: PMC8141573 DOI: 10.3389/fcell.2021.611443] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/05/2021] [Indexed: 12/19/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent one of the largest membrane protein families that participate in various physiological and pathological activities. Accumulating structural evidences have revealed how GPCR activation induces conformational changes to accommodate the downstream G protein or β-arrestin. Multiple GPCR functional assays have been developed based on Förster resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) sensors to monitor the conformational changes in GPCRs, GPCR/G proteins, or GPCR/β-arrestin, especially over the past two decades. Here, we will summarize how these sensors have been optimized to increase the sensitivity and compatibility for application in different GPCR classes using various labeling strategies, meanwhile provide multiple solutions in functional assays for high-throughput drug screening.
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Affiliation(s)
- Yiwei Zhou
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jiyong Meng
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Chanjuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
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17
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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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18
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Structural mechanism of cooperative activation of the human calcium-sensing receptor by Ca 2+ ions and L-tryptophan. Cell Res 2021; 31:383-394. [PMID: 33603117 PMCID: PMC8115157 DOI: 10.1038/s41422-021-00474-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023] Open
Abstract
The human calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor (GPCR) responsible for maintaining Ca2+ homeostasis in the blood. The general consensus is that extracellular Ca2+ is the principal agonist of CaSR. Aliphatic and aromatic L-amino acids, such as L-Phe and L-Trp, increase the sensitivity of CaSR towards Ca2+ and are considered allosteric activators. Crystal structures of the extracellular domain (ECD) of CaSR dimer have demonstrated Ca2+ and L-Trp binding sites and conformational changes of the ECD upon Ca2+/L-Trp binding. However, it remains to be understood at the structural level how Ca2+/L-Trp binding to the ECD leads to conformational changes in transmembrane domains (TMDs) and consequent CaSR activation. Here, we determined the structures of full-length human CaSR in the inactive state, Ca2+- or L-Trp-bound states, and Ca2+/L-Trp-bound active state using single-particle cryo-electron microscopy. Structural studies demonstrate that L-Trp binding induces the closure of the Venus flytrap (VFT) domain of CaSR, bringing the receptor into an intermediate active state. Ca2+ binding relays the conformational changes from the VFT domains to the TMDs, consequently inducing close contact between the two TMDs of dimeric CaSR, activating the receptor. Importantly, our structural and functional studies reveal that Ca2+ ions and L-Trp activate CaSR cooperatively. Amino acids are not able to activate CaSR alone, but can promote the receptor activation in the presence of Ca2+. Our data provide complementary insights into the activation of class C GPCRs and may aid in the development of novel drugs targeting CaSR.
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19
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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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20
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Zhang J, Qu L, Wu L, Tang X, Luo F, Xu W, Xu Y, Liu ZJ, Hua T. Structural insights into the activation initiation of full-length mGlu1. Protein Cell 2020; 12:662-667. [PMID: 33278019 PMCID: PMC8310541 DOI: 10.1007/s13238-020-00808-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2020] [Indexed: 11/15/2022] Open
Affiliation(s)
- Jinyi Zhang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Lu Qu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Lijie Wu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Xiaomeng Tang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Feng Luo
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Weixiu Xu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yueming Xu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Zhi-Jie Liu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Tian Hua
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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21
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Ahmad R, Dalziel JE. G Protein-Coupled Receptors in Taste Physiology and Pharmacology. Front Pharmacol 2020; 11:587664. [PMID: 33390961 PMCID: PMC7774309 DOI: 10.3389/fphar.2020.587664] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.
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Affiliation(s)
- Raise Ahmad
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
| | - Julie E Dalziel
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
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22
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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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23
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Illuminating the allosteric modulation of the calcium-sensing receptor. Proc Natl Acad Sci U S A 2020; 117:21711-21722. [PMID: 32817431 DOI: 10.1073/pnas.1922231117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Many membrane receptors are regulated by nutrients. However, how these nutrients control a single receptor remains unknown, even in the case of the well-studied calcium-sensing receptor CaSR, which is regulated by multiple factors, including ions and amino acids. Here, we developed an innovative cell-free Förster resonance energy transfer (FRET)-based conformational CaSR biosensor to clarify the main conformational changes associated with activation. By allowing a perfect control of ambient nutrients, this assay revealed that Ca2+ alone fully stabilizes the active conformation, while amino acids behave as pure positive allosteric modulators. Based on the identification of Ca2+ activation sites, we propose a molecular basis for how these different ligands cooperate to control CaSR activation. Our results provide important information on CaSR function and improve our understanding of the effects of genetic mutations responsible for human diseases. They also provide insights into how a receptor can integrate signals from various nutrients to better adapt to the cell response.
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24
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Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
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Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
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25
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Sutkeviciute I, Vilardaga JP. Structural insights into emergent signaling modes of G protein-coupled receptors. J Biol Chem 2020; 295:11626-11642. [PMID: 32571882 DOI: 10.1074/jbc.rev120.009348] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/21/2020] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of cell membrane proteins, with >800 GPCRs in humans alone, and recognize highly diverse ligands, ranging from photons to large protein molecules. Very important to human medicine, GPCRs are targeted by about 35% of prescription drugs. GPCRs are characterized by a seven-transmembrane α-helical structure, transmitting extracellular signals into cells to regulate major physiological processes via heterotrimeric G proteins and β-arrestins. Initially viewed as receptors whose signaling via G proteins is delimited to the plasma membrane, it is now recognized that GPCRs signal also at various intracellular locations, and the mechanisms and (patho)physiological relevance of such signaling modes are actively investigated. The propensity of GPCRs to adopt different signaling modes is largely encoded in the structural plasticity of the receptors themselves and of their signaling complexes. Here, we review emerging modes of GPCR signaling via endosomal membranes and the physiological implications of such signaling modes. We further summarize recent structural insights into mechanisms of GPCR activation and signaling. We particularly emphasize the structural mechanisms governing the continued GPCR signaling from endosomes and the structural aspects of the GPCR resensitization mechanism and discuss the recently uncovered and important roles of lipids in these processes.
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Affiliation(s)
- Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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26
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Structure-based discovery and development of metabotropic glutamate receptor 5 negative allosteric modulators. ADVANCES IN PHARMACOLOGY 2020; 88:35-58. [PMID: 32416871 DOI: 10.1016/bs.apha.2020.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
The metabotropic glutamate (mGlu) receptors are a family of eight class C G protein-coupled receptors (GPCRs) which modulate cell signaling and synaptic transmission to the major excitatory neurotransmitter l-glutamate (l-glutamic acid). Due to their role in modulating glutamate response, their widespread distribution in the central nervous system (CNS) and some evidence of dysregulation in disease, the mGlu receptors have become attractive pharmacological targets. As the orthosteric (glutamate) binding site is highly conserved across the eight mGlu receptors, it is difficult not only to generate ligands with subtype selectivity but, due to the nature of the binding site, with suitable drug-like properties to allow oral bioavailability and CNS penetration. Selective pharmacological targeting of a single receptor subtype can be achieved by targeting alternative (allosteric) binding sites. The nature of the allosteric binding pockets allows ligands to be developed that have good physical chemical properties as evidenced by several allosteric modulators of mGlu receptors entering clinical trials. The first negative allosteric modulators of the metabotropic glutamate 5 (mGlu5) receptor were discovered from high throughput screening activities. An alternative approach to drug discovery is to use structural knowledge to enable structure-based drug design (SBDD), which allows the design of molecules in a more rational, rather than empirical, fashion. Here we will describe the process of SBDD in the discovery of the mGlu5 negative allosteric modulator HTL0014242 and describe how knowledge of receptor structure can also be used to gain insights into the receptor activation mechanisms.
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27
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Lei T, Hu Z, Ding R, Chen J, Li S, Zhang F, Pu X, Zhao N. Exploring the Activation Mechanism of a Metabotropic Glutamate Receptor Homodimer via Molecular Dynamics Simulation. ACS Chem Neurosci 2020; 11:133-145. [PMID: 31815422 DOI: 10.1021/acschemneuro.9b00425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Metabotropic glutamate receptors of class C GPCRs exist as constitutive dimers, which play important roles in activating excitatory synapses of the central nervous system. However, the activation mechanism induced by agonists has not been clarified in experiments. To address the problem, we used microsecond all-atom molecular dynamics (MD) simulation couple with protein structure network (PSN) to explore the glutamate-induced activation for the mGluR1 homodimer. The results indicate that glutamate binding stabilizes not only the closure of Venus flytrap domains but also the polar interaction of LB2-LB2, in turn keeping the extracelluar domain in the active state. The activation of the extracelluar domain drives transmembrane domains (TMDs) of the two protomers closer and induces asymmetric activation for the TMD domains of the two protomers. One protomer with lower binding affinity to the agonist is activated, while the other protomer with higher binding energy is still in the inactive state. The PSN analysis identifies the allosteric regulation pathway from the ligand-binding pocket in the extracellular domain to the G-protein binding site in the intracellular TMD region and further reveals that the asymmetric activation is attributed to a combination of trans-pathway and cis-pathway regulations from two glumatates, rather than a single activation pathway. These observations could provide valuable molecular information for understanding of the structure and the implications in drug efficacy for the class C GPCR dimers.
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Affiliation(s)
- Ting Lei
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Zhenxin Hu
- College of Computer Science, Sichuan University, Chengdu 610064, China
| | - Ruolin Ding
- West China School of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jianfang Chen
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shiqi Li
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Fuhui Zhang
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xuemei Pu
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Nanrong Zhao
- College of Chemistry, Sichuan University, Chengdu 610064, China
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28
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Kniazeff J. The different aspects of the GABAB receptor allosteric modulation. FROM STRUCTURE TO CLINICAL DEVELOPMENT: ALLOSTERIC MODULATION OF G PROTEIN-COUPLED RECEPTORS 2020; 88:83-113. [DOI: 10.1016/bs.apha.2020.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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29
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Vécsei L, Lukács M, Tajti J, Fülöp F, Toldi J, Edvinsson L. The Therapeutic Impact of New Migraine Discoveries. Curr Med Chem 2019; 26:6261-6281. [PMID: 29848264 DOI: 10.2174/0929867325666180530114534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 04/18/2018] [Accepted: 05/03/2018] [Indexed: 01/03/2023]
Abstract
BACKGROUND Migraine is one of the most disabling neurological conditions and associated with high socio-economic costs. Though certain aspects of the pathomechanism of migraine are still incompletely understood, the leading hypothesis implicates the role of the activation of the trigeminovascular system. Triptans are considered to be the current gold standard therapy for migraine attacks; however, their use in clinical practice is limited. Prophylactic treatment includes non-specific approaches for migraine prevention. All these support the need for future studies in order to develop innovative anti-migraine drugs. OBJECTIVE The present study is a review of the current literature regarding new therapeutic lines in migraine research. METHODS A systematic literature search in the database of PUBMED was conducted concerning therapeutic strategies in a migraine published until July 2017. RESULTS Ongoing clinical trials with 5-HT1F receptor agonists and glutamate receptor antagonists offer promising new aspects for acute migraine treatment. Monoclonal antibodies against CGRP and the CGRP receptor are revolutionary in preventive treatment; however, further long-term studies are needed to test their tolerability. Preclinical studies show positive results with PACAP- and kynurenic acid-related treatments. Other promising therapeutic strategies (such as those targeting TRPV1, substance P, NOS, or orexin) have failed to show efficacy in clinical trials. CONCLUSION Due to their side-effects, current therapeutic approaches are not suitable for all migraine patients. Especially frequent episodic and chronic migraine represents a therapeutic challenge for researchers. Clinical and preclinical studies are needed to untangle the pathophysiology of migraine in order to develop new and migraine-specific therapies.
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Affiliation(s)
- László Vécsei
- Department of Neurology, University of Szeged, Szeged, Hungary.,MTASZTE Neuroscience Research Group, Szeged, Hungary
| | - Melinda Lukács
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - János Tajti
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Ferenc Fülöp
- Institute of Pharmaceutical Chemistry and MTA-SZTE Research Group for Stereochemistry, University of Szeged, Szeged, Hungary
| | - József Toldi
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Lars Edvinsson
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden.,Department of Clinical Experimental Research, Copenhagen University, Glostrup Hospital, Copenhagen, Denmark
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30
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Hao J, Chen Q. Insights into the Structural Aspects of the mGlu Receptor Orthosteric Binding Site. Curr Top Med Chem 2019; 19:2421-2446. [PMID: 31660833 DOI: 10.2174/1568026619666191011094935] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/28/2019] [Accepted: 09/04/2019] [Indexed: 02/06/2023]
Abstract
The amino terminal domain (ATD) of the metabotropic glutamate (mGlu) receptors contains the orthosteric glutamate recognition site, which is highly conserved across the eight mGlu receptor subtypes. In total, 29 X-ray crystal structures of the mGlu ATD proteins have been reported to date. These structures span across 3 subgroups and 6 subtypes, and include apo, agonist- and antagonist-bound structures. We will discuss the insights gained from the analysis of these structures with the focus on the interactions contributing to the observed group and subtype selectivity for select agonists. Furthermore, we will define the full expanded orthosteric ligand binding pocket (LBP) of the mGlu receptors, and discuss the macroscopic features of the mGlu ATD proteins.
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Affiliation(s)
- Junliang Hao
- Discovery Chemistry Research and Technologies, Lilly Research Laboratory, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, United States
| | - Qi Chen
- Discovery Chemistry Research and Technologies, Lilly Research Laboratory, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, United States
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31
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Dal Prà I, Armato U, Chiarini A. Family C G-Protein-Coupled Receptors in Alzheimer's Disease and Therapeutic Implications. Front Pharmacol 2019; 10:1282. [PMID: 31719824 PMCID: PMC6826475 DOI: 10.3389/fphar.2019.01282] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), particularly its sporadic or late-onset form (SAD/LOAD), is the most prevalent (96–98% of cases) neurodegenerative dementia in aged people. AD’s neuropathology hallmarks are intrabrain accumulation of amyloid-β peptides (Aβs) and of hyperphosphorylated Tau (p-Tau) proteins, diffuse neuroinflammation, and progressive death of neurons and oligodendrocytes. Mounting evidences suggest that family C G-protein-coupled receptors (GPCRs), which include γ-aminobutyric acid B receptors (GABABRs), metabotropic glutamate receptors (mGluR1-8), and the calcium-sensing receptor (CaSR), are involved in many neurotransmitter systems that dysfunction in AD. This review updates the available knowledge about the roles of GPCRs, particularly but not exclusively those expressed by brain astrocytes, in SAD/LOAD onset and progression, taking stock of their respective mechanisms of action and of their potential as anti-AD therapeutic targets. In particular, GABABRs prevent Aβs synthesis and neuronal hyperexcitability and group I mGluRs play important pathogenetic roles in transgenic AD-model animals. Moreover, the specific binding of Aβs to the CaSRs of human cortical astrocytes and neurons cultured in vitro engenders a pathological signaling that crucially promotes the surplus synthesis and release of Aβs and hyperphosphorylated Tau proteins, and also of nitric oxide, vascular endothelial growth factor-A, and proinflammatory agents. Concurrently, Aβs•CaSR signaling hinders the release of soluble (s)APP-α peptide, a neurotrophic agent and GABABR1a agonist. Altogether these effects progressively kill human cortical neurons in vitro and likely also in vivo. Several CaSR’s negative allosteric modulators suppress all the noxious effects elicited by Aβs•CaSR signaling in human cortical astrocytes and neurons thus safeguarding neurons’ viability in vitro and raising hopes about their potential therapeutic benefits in AD patients. Further basic and clinical investigations on these hot topics are needed taking always heed that activation of the several brain family C GPCRs may elicit divergent upshots according to the models studied.
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Affiliation(s)
- Ilaria Dal Prà
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
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32
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Quast RB, Margeat E. Studying GPCR conformational dynamics by single molecule fluorescence. Mol Cell Endocrinol 2019; 493:110469. [PMID: 31163201 DOI: 10.1016/j.mce.2019.110469] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023]
Abstract
Over the last decades, G protein coupled receptors (GPCRs) have experienced a tremendous amount of attention, which has led to a boost of structural and pharmacological insights on this large membrane protein superfamily involved in various essential physiological functions. Recently, evidence has emerged that, rather than being activated by ligands in an on/off manner switching from an inactive to an active state, GPCRs exhibit high structural flexibility in the absence and even in the presence of ligands. So far the physiological as well as pharmacological impact of this structural flexibility remains largely unexplored albeit its potential role in precisely fine-tuning receptor function and regulating the specificity of signal transduction into the cell. By complementing other biophysical approaches, single molecule fluorescence (SMF) offers the advantage of monitoring structural dynamics in biomolecules in real-time, with minimal structural invasiveness and in the context of complex biological environments. In this review a general introduction to GPCR structural dynamics is given followed by a presentation of SMF methods used to explore them. Particular attention is paid to single molecule Förster resonance energy transfer (smFRET), a key method to measure actual distance changes between two probes, and highlight conformational changes occurring at timescales relevant for protein conformational movements. The available literature reporting on GPCR structural dynamics by SMF is discussed with a focus on the newly gained biological insights on receptor activation and signaling, in particular for the β2 adrenergic and the metabotropic glutamate receptors.
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Affiliation(s)
- Robert B Quast
- CBS, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Emmanuel Margeat
- CBS, CNRS, INSERM, Université de Montpellier, Montpellier, France.
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33
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Gutzeit VA, Thibado J, Stor DS, Zhou Z, Blanchard SC, Andersen OS, Levitz J. Conformational dynamics between transmembrane domains and allosteric modulation of a metabotropic glutamate receptor. eLife 2019; 8:45116. [PMID: 31172948 PMCID: PMC6588349 DOI: 10.7554/elife.45116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 06/06/2019] [Indexed: 01/01/2023] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are class C, synaptic G-protein-coupled receptors (GPCRs) that contain large extracellular ligand binding domains (LBDs) and form constitutive dimers. Despite the existence of a detailed picture of inter-LBD conformational dynamics and structural snapshots of both isolated domains and full-length receptors, it remains unclear how mGluR activation proceeds at the level of the transmembrane domains (TMDs) and how TMD-targeting allosteric drugs exert their effects. Here, we use time-resolved functional and conformational assays to dissect the mechanisms by which allosteric drugs activate and modulate mGluR2. Single-molecule subunit counting and inter-TMD fluorescence resonance energy transfer measurements in living cells reveal LBD-independent conformational rearrangements between TMD dimers during receptor modulation. Using these assays along with functional readouts, we uncover heterogeneity in the magnitude, direction, and the timing of the action of both positive and negative allosteric drugs. Together our experiments lead to a three-state model of TMD activation, which provides a framework for understanding how inter-subunit rearrangements drive class C GPCR activation.
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Affiliation(s)
- Vanessa A Gutzeit
- Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States
| | - Jordana Thibado
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States
| | - Daniel Starer Stor
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, United States
| | - Scott C Blanchard
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States.,Department of Physiology and Biophysics, Weill Cornell Medicine, New York, United States.,Tri-Institutional PhD Program in Chemical Biology, New York, United States
| | - Olaf S Andersen
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States.,Department of Physiology and Biophysics, Weill Cornell Medicine, New York, United States
| | - Joshua Levitz
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, United States.,Tri-Institutional PhD Program in Chemical Biology, New York, United States.,Department of Biochemistry, Weill Cornell Medicine, New York, United States
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34
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Pin JP, Kniazeff J, Prézeau L, Liu JF, Rondard P. GPCR interaction as a possible way for allosteric control between receptors. Mol Cell Endocrinol 2019; 486:89-95. [PMID: 30849406 DOI: 10.1016/j.mce.2019.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/17/2022]
Abstract
For more than twenty years now, GPCR dimers and larger oligomers have been the subject of intense debates. Evidence for a role of such complexes in receptor trafficking to and from the plasma membrane have been provided. However, one main issue is of course to determine whether or not such a phenomenon can be responsible for an allosteric and reciprocal control (allosteric control) of the subunits. Such a possibility would indeed add to the possible ways a cell integrates various signals targeting GPCRs. Among the large GPCR family, the class C receptors that include mGlu and GABAB receptors, represent excellent models to examine such a possibility as they are mandatory dimers. In the present review, we will report on the observed allosteric interaction between the subunits of class C GPCRs, both mGluRs and GABABRs, and on the structural bases of these interactions. We will then discuss these findings for other GPCR types such as the rhodopsin-like class A receptors. We will show that many of the observations made with class C receptors have also been reported with class A receptors, suggesting that the mechanisms involved in the allosteric control between subunits in GPCR dimers may not be unique to class C GPCRs.
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Affiliation(s)
- Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Laurent Prézeau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jiang-Feng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
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Park J, Selvam B, Sanematsu K, Shigemura N, Shukla D, Procko E. Structural architecture of a dimeric class C GPCR based on co-trafficking of sweet taste receptor subunits. J Biol Chem 2019; 294:4759-4774. [PMID: 30723160 DOI: 10.1074/jbc.ra118.006173] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/24/2019] [Indexed: 01/06/2023] Open
Abstract
Class C G protein-coupled receptors (GPCRs) are obligatory dimers that are particularly important for neuronal responses to endogenous and environmental stimuli. Ligand recognition through large extracellular domains leads to the reorganization of transmembrane regions to activate G protein signaling. Although structures of individual domains are known, the complete architecture of a class C GPCR and the mechanism of interdomain coupling during receptor activation are unclear. By screening a mutagenesis library of the human class C sweet taste receptor subunit T1R2, we enhanced surface expression and identified a dibasic intracellular retention motif that modulates surface expression and co-trafficking with its heterodimeric partner T1R3. Using a highly expressed T1R2 variant, dimerization sites along the entire subunit within all the structural domains were identified by a comprehensive mutational scan for co-trafficking with T1R3 in human cells. The data further reveal that the C terminus of the extracellular cysteine-rich domain needs to be properly folded for T1R3 dimerization and co-trafficking, but not for surface expression of T1R2 alone. These results guided the modeling of the T1R2-T1R3 dimer in living cells, which predicts a twisted arrangement of domains around the central axis, and a continuous folded structure between transmembrane domain loops and the cysteine-rich domains. These insights have implications for how conformational changes between domains are coupled within class C GPCRs.
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Affiliation(s)
- Jihye Park
- From the Departments of Biochemistry and
| | - Balaji Selvam
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | - Keisuke Sanematsu
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriatsu Shigemura
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Diwakar Shukla
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
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Hao J, Chen Q. On the origin of the 2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate scaffold's unique group II selectivity for the mGlu receptors. Bioorg Med Chem Lett 2019; 29:297-301. [PMID: 30470494 DOI: 10.1016/j.bmcl.2018.11.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/11/2018] [Accepted: 11/14/2018] [Indexed: 12/27/2022]
Abstract
Analogs based on the 2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate scaffold showed high potency and selectivity as both group II mGlu receptors orthosteric agonists and antagonists. This scaffold was initially designed to mimic the fully extended glutamate backbone conformation that was hypothesized to be the active conformation for the group II mGlu receptors. With the availability of crystal structures of l-Glu-bound amino terminal domain proteins from multiple mGlu receptor subtypes spanning all three subgroups, a new steric hindrance hypothesis was proposed to account for the scaffold's unique group II selectivity that explores the subtle distance differences between the α-carbon of l-Glu and the center of the tyrosine phenyl ring from the bottom lobe (e.g. Y216 of mGlu2).
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Affiliation(s)
- Junliang Hao
- Discovery Chemistry Research and Technologies, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
| | - Qi Chen
- Discovery Chemistry Research and Technologies, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA
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Lee JY, Krieger J, Herguedas B, García-Nafría J, Dutta A, Shaikh SA, Greger IH, Bahar I. Druggability Simulations and X-Ray Crystallography Reveal a Ligand-Binding Site in the GluA3 AMPA Receptor N-Terminal Domain. Structure 2018; 27:241-252.e3. [PMID: 30528594 DOI: 10.1016/j.str.2018.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/25/2018] [Accepted: 10/18/2018] [Indexed: 11/19/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission in the brain. Their dysfunction is implicated in many neurological disorders, rendering iGluRs potential drug targets. Here, we performed a systematic analysis of the druggability of two major iGluR subfamilies, using molecular dynamics simulations in the presence of drug-like molecules. We demonstrate the applicability of druggability simulations by faithfully identifying known agonist and modulator sites on AMPA receptors (AMPARs) and NMDA receptors. Simulations produced the expected allosteric changes of the AMPAR ligand-binding domain in response to agonist. We also identified a novel ligand-binding site specific to the GluA3 AMPAR N-terminal domain (NTD), resulting from its unique conformational flexibility that we explored further with crystal structures trapped in vastly different states. In addition to providing an in-depth analysis into iGluR NTD dynamics, our approach identifies druggable sites and permits the determination of pharmacophoric features toward novel iGluR modulators.
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Affiliation(s)
- Ji Young Lee
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, 3501 Fifth Avenue, Suite 3064 BST3, Pittsburgh, PA 15260, USA
| | - James Krieger
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, 3501 Fifth Avenue, Suite 3064 BST3, Pittsburgh, PA 15260, USA
| | - Beatriz Herguedas
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Javier García-Nafría
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Anindita Dutta
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, 3501 Fifth Avenue, Suite 3064 BST3, Pittsburgh, PA 15260, USA
| | - Saher A Shaikh
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Ingo H Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, 3501 Fifth Avenue, Suite 3064 BST3, Pittsburgh, PA 15260, USA.
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Chen Q, Ho JD, Ashok S, Vargas MC, Wang J, Atwell S, Bures M, Schkeryantz JM, Monn JA, Hao J. Structural Basis for ( S)-3,4-Dicarboxyphenylglycine (DCPG) As a Potent and Subtype Selective Agonist of the mGlu 8 Receptor. J Med Chem 2018; 61:10040-10052. [PMID: 30365309 DOI: 10.1021/acs.jmedchem.8b01120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
( S)-3,4-Dicarboxyphenylglycine (DCPG) was first reported in 2001 as a potent orthosteric agonist with high subtype selectivity for the mGlu8 receptor, but the structural basis for its high selectivity is not well understood. We have solved a cocrystal structure of recombinant human mGlu8 amino terminal domain (ATD) protein bound to ( S)-DCPG, which possesses the largest lobe opening angle observed to date among known agonist-bound mGlu ATD crystal structures. The binding conformation of ( S)-DCPG observed in the crystal structure is significantly different from that in the homology model built from an l-glutamate-bound rat mGlu1 ATD crystal structure, which has a smaller lobe opening angle. This highlights the importance of considering various lobe opening angles when modeling mGlu ATD-ligand complex. New homology models of other mGlu receptors based on the ( S)-DCPG-bound mGlu8 ATD crystal structure were explored to rationalize ( S)-DCPG's high mGlu8 receptor subtype selectivity.
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Abstract
Agonists and most natural ligands bind to receptors in their inactive state and quickly induce an active receptor conformation that initiates cell signaling. The active receptor state initiates signaling because of its structural complementariness with coupling proteins that activate signaling pathways, such as G proteins and G protein-coupled receptor kinases. Agonist bias refers to the propensity of an agonist to direct receptor signaling through one pathway relative to another. Thus, if the agonist exhibits much higher affinity for active state 1 compared to active state 2, it will cause a robust activation of receptor coupling protein 1 but not 2, and ultimately, a preferential stimulation of signaling pathway 1. Biased agonists are potentially more selective therapeutic agents because there are numerous cases where the therapeutic and adverse effects of an agonist are mediated by distinct pathways involving G proteins and β-arrestin. Given the mechanism for agonist bias, the most straightforward approach for quantifying bias involves the estimation of agonist affinity for the inactive receptor state and the active receptor states involved in signaling through different pathways. The approach provides quantitative estimates of the sensitivities of different signaling pathways, enabling one to determine to what extent the observed selectivity is caused by agonist or system bias. In addition, the approach is a powerful adjunct to in silico docking studies and can be applied to in vivo assays, structure-activity relationships, and the analysis of published agonist concentration-response curves.
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Gates C, Backos DS, Reigan P, Kang HJ, Koerner C, Mirzaei J, Natale NR. Isoxazolo[3,4-d]pyridazinones positively modulate the metabotropic glutamate subtypes 2 and 4. Bioorg Med Chem 2018; 26:4797-4803. [PMID: 30143366 PMCID: PMC6675577 DOI: 10.1016/j.bmc.2018.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/01/2018] [Accepted: 08/09/2018] [Indexed: 11/29/2022]
Abstract
Isoxazolo[3,4-d] pyridazinones ([3,4-d]s) are selective positive modulators of the metabotropic glutamate receptors (mGluRs) subtypes 2 and 4, with no functional cross reactivity at mGluR1a, mGLuR5 or mGluR8. Modest binding for two of the [3,4-d]s is observed at the allosteric fenobam mGluR5 site, but not sufficient to translate into a functional effect. The structure activity relationship (SAR) for mGluR2 and mGluR4 are distinct: the compounds which select for mGluR2 all contain fluorine on the N-6 aryl group. Furthermore, the [3,4-d]s in this study showed no significant binding at inhibitory GABAA, nor excitatory NMDA receptors, and previously we had disclosed that they lack significant activity at the System Xc-Antiporter. A homology model based on Conn's mGluR1 crystal structure was examined, and suggested explanations for a preference for allosteric over orthosteric binding, subtype selectivity, and suggested avenues for optimization of efficacy as a reasonable working hypothesis.
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Affiliation(s)
- Christina Gates
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, United States
| | - Donald S Backos
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, United States
| | - Philip Reigan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, United States
| | - Hye Jin Kang
- Psychoactive Drug Screening Program, University of North Carolina at Chapel Hill, Department of Pharmacology, School of Medicine, 2113 Genetics Medicine Building, 120 Mason Farm Road, Chapel Hill, NC 27599, United States
| | - Chris Koerner
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, United States
| | - Joseph Mirzaei
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, United States
| | - N R Natale
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, United States; Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, United States.
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Belhocine A, Veglianese P, Hounsou C, Dupuis E, Acher F, Durroux T, Goudet C, Pin JP. Profiling of orthosteric and allosteric group-III metabotropic glutamate receptor ligands on various G protein-coupled receptors with Tag-lite ® assays. Neuropharmacology 2018; 140:233-245. [PMID: 30099051 DOI: 10.1016/j.neuropharm.2018.07.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 12/21/2022]
Abstract
Group-III metabotropic glutamate (mGlu) receptors are important synaptic regulators and are potential druggable targets for Parkinson disease, autism and pain. Potential drugs include orthosteric agonists in the glutamate binding extracellular domain and positive allosteric modulators interacting with seven-pass transmembrane domains. Orthosteric agonists are rarely completely specific for an individual group-III mGlu subtype. Furthermore they often fail to pass the blood-brain barrier and they constitutively activate their target receptor. These properties limit the potential therapeutic use of orthosteric agonists. Allosteric modulators are more specific and maintain the biological activity of the targeted receptor. However, they bind in a hydrophobic pocket and this limits their bio-availability and increases possible off-target action. It is therefore important to characterize the action of potential drug targets with a multifaceted and deeply informative assay. Here we aimed at multifaceted deep profiling of the effect of seven different agonists, and seven positive allosteric modulators on 34 different G protein-coupled receptors by a Tag-lite® assay. Our results did not reveal off-target activity of mGlu orthosteric agonists. However, five allosteric modulators had either positive or negative effects on non-cognate G protein-coupled receptors. In conclusion, we demonstrate the power of the Tag-lite® assay for potential drug ligand profiling on G protein-coupled receptors and its potential to identify positive allosteric compounds.
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Affiliation(s)
| | | | | | | | - Francine Acher
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR8601, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | | | - Cyril Goudet
- IGF, Univ. Montpellier, CNRS, INSERM, Montpellier, France
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Frangaj A, Fan QR. Structural biology of GABA B receptor. Neuropharmacology 2018; 136:68-79. [PMID: 29031577 PMCID: PMC5897222 DOI: 10.1016/j.neuropharm.2017.10.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022]
Abstract
Metabotropic GABAB receptor is a G protein-coupled receptor (GPCR) that mediates slow and prolonged inhibitory neurotransmission in the brain. It functions as a constitutive heterodimer composed of the GABAB1 and GABAB2 subunits. Each subunit contains three domains; the extracellular Venus flytrap module, seven-helix transmembrane region and cytoplasmic tail. In recent years, the three-dimensional structures of GABAB receptor extracellular and intracellular domains have been elucidated. These structures reveal the molecular basis of ligand recognition, receptor heterodimerization and receptor activation. Here we provide a brief review of the GABAB receptor structures, with an emphasis on describing the different ligand-bound states of the receptor. We will also compare these with the known structures of related GPCRs to shed light on the molecular mechanisms of activation and regulation in the GABAB system, as well as GPCR dimers in general. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Aurel Frangaj
- Department of Pharmacology, Columbia University, New York, NY 10032, USA
| | - Qing R Fan
- Department of Pharmacology, Columbia University, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University, New York, NY 10032, USA.
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Nasrallah C, Rottier K, Marcellin R, Compan V, Font J, Llebaria A, Pin JP, Banères JL, Lebon G. Direct coupling of detergent purified human mGlu 5 receptor to the heterotrimeric G proteins Gq and Gs. Sci Rep 2018. [PMID: 29535347 PMCID: PMC5849714 DOI: 10.1038/s41598-018-22729-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The metabotropic glutamate (mGlu) receptors are class C G protein-coupled receptors (GPCRs) that modulate synaptic activity and plasticity throughout the mammalian brain. Signal transduction is initiated by glutamate binding to the venus flytrap domains (VFT), which initiates a conformational change that is transmitted to the conserved heptahelical domains (7TM) and results ultimately in the activation of intracellular G proteins. While both mGlu1 and mGlu5 activate Gαq G-proteins, they also increase intracellular cAMP concentration through an unknown mechanism. To study directly the G protein coupling properties of the human mGlu5 receptor homodimer, we purified the full-length receptor, which required careful optimisation of the expression, N-glycosylation and purification. We successfully purified functional mGlu5 that activated the heterotrimeric G protein Gq. The high-affinity agonist-PAM VU0424465 also activated the purified receptor in the absence of an orthosteric agonist. In addition, it was found that purified mGlu5 was capable of activating the G protein Gs either upon stimulation with VU0424465 or glutamate, although the later induced a much weaker response. Our findings provide important mechanistic insights into mGlu5 G protein-dependent activity and selectivity.
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Affiliation(s)
- Chady Nasrallah
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Karine Rottier
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Romain Marcellin
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Vincent Compan
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Joan Font
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), CNRS, Univ. Montpellier, ENSCM, Montpellier, France
| | - Guillaume Lebon
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Montpellier, F-34000, Montpellier, France.
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Selvam C, Lemasson IA, Brabet I, Oueslati N, Karaman B, Cabaye A, Tora AS, Commare B, Courtiol T, Cesarini S, McCort-Tranchepain I, Rigault D, Mony L, Bessiron T, McLean H, Leroux FR, Colobert F, Daniel H, Goupil-Lamy A, Bertrand HO, Goudet C, Pin JP, Acher FC. Increased Potency and Selectivity for Group III Metabotropic Glutamate Receptor Agonists Binding at Dual sites. J Med Chem 2018; 61:1969-1989. [DOI: 10.1021/acs.jmedchem.7b01438] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Chelliah Selvam
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Isabelle A. Lemasson
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Isabelle Brabet
- IGF, CNRS, INSERM, Université Montpellier, F-34094 Montpellier, France
| | - Nadia Oueslati
- IGF, CNRS, INSERM, Université Montpellier, F-34094 Montpellier, France
| | - Berin Karaman
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Alexandre Cabaye
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Amélie S. Tora
- IGF, CNRS, INSERM, Université Montpellier, F-34094 Montpellier, France
| | - Bruno Commare
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
- UMR 7509/CNRS/ECPM, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg 02, France
| | - Tiphanie Courtiol
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Sara Cesarini
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Isabelle McCort-Tranchepain
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Delphine Rigault
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Laetitia Mony
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
- Institut de Biologie, Ecole Normale Supérieure, CNRS UMR 8197, INSERM U1024, PSL University, 46 rue d’Ulm, 75005 Paris, France
| | - Thomas Bessiron
- Pharmacologie et Biochimie de la Synapse, Université Paris-Sud/CNRS/NeuroPSI−UMR 9197, F-91405 Orsay, France
| | - Heather McLean
- Pharmacologie et Biochimie de la Synapse, Université Paris-Sud/CNRS/NeuroPSI−UMR 9197, F-91405 Orsay, France
| | - Frédéric R. Leroux
- UMR 7509/CNRS/ECPM, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg 02, France
| | - Françoise Colobert
- UMR 7509/CNRS/ECPM, Université de Strasbourg, 25 Rue Becquerel, 67087 Strasbourg 02, France
| | - Hervé Daniel
- Pharmacologie et Biochimie de la Synapse, Université Paris-Sud/CNRS/NeuroPSI−UMR 9197, F-91405 Orsay, France
| | - Anne Goupil-Lamy
- BIOVIA, Dassault Systèmes, 10 rue Marcel Dassault, CS 40501, 78946 Vélizy-Villacoublay Cedex, France
| | - Hugues-Olivier Bertrand
- BIOVIA, Dassault Systèmes, 10 rue Marcel Dassault, CS 40501, 78946 Vélizy-Villacoublay Cedex, France
| | - Cyril Goudet
- IGF, CNRS, INSERM, Université Montpellier, F-34094 Montpellier, France
| | - Jean-Philippe Pin
- IGF, CNRS, INSERM, Université Montpellier, F-34094 Montpellier, France
| | - Francine C. Acher
- Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France
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Determination of L-AP4-bound human mGlu8 receptor amino terminal domain structure and the molecular basis for L-AP4’s group III mGlu receptor functional potency and selectivity. Bioorg Med Chem Lett 2018; 28:612-617. [DOI: 10.1016/j.bmcl.2018.01.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/16/2018] [Accepted: 01/19/2018] [Indexed: 01/28/2023]
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46
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Scholler P, Nevoltris D, de Bundel D, Bossi S, Moreno-Delgado D, Rovira X, Møller TC, El Moustaine D, Mathieu M, Blanc E, McLean H, Dupuis E, Mathis G, Trinquet E, Daniel H, Valjent E, Baty D, Chames P, Rondard P, Pin JP. Allosteric nanobodies uncover a role of hippocampal mGlu2 receptor homodimers in contextual fear consolidation. Nat Commun 2017; 8:1967. [PMID: 29213077 PMCID: PMC5719040 DOI: 10.1038/s41467-017-01489-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 09/15/2017] [Indexed: 11/09/2022] Open
Abstract
Antibodies have enormous therapeutic and biotechnology potential. G protein-coupled receptors (GPCRs), the main targets in drug development, are of major interest in antibody development programs. Metabotropic glutamate receptors are dimeric GPCRs that can control synaptic activity in a multitude of ways. Here we identify llama nanobodies that specifically recognize mGlu2 receptors, among the eight subtypes of mGluR subunits. Among these nanobodies, DN10 and 13 are positive allosteric modulators (PAM) on homodimeric mGlu2, while DN10 displays also a significant partial agonist activity. DN10 and DN13 have no effect on mGlu2-3 and mGlu2-4 heterodimers. These PAMs enhance the inhibitory action of the orthosteric mGlu2/mGlu3 agonist, DCG-IV, at mossy fiber terminals in the CA3 region of hippocampal slices. DN13 also impairs contextual fear memory when injected in the CA3 region of hippocampal region. These data highlight the potential of developing antibodies with allosteric actions on GPCRs to better define their roles in vivo.
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Affiliation(s)
- Pauline Scholler
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
- Cisbio Bioassays, F-30200, Codolet, France
| | - Damien Nevoltris
- Cisbio Bioassays, F-30200, Codolet, France
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France
| | - Dimitri de Bundel
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Simon Bossi
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | - David Moreno-Delgado
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Thor C Møller
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Driss El Moustaine
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Michaël Mathieu
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Emilie Blanc
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Heather McLean
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | | | | | | | - Hervé Daniel
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | - Emmanuel Valjent
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Daniel Baty
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France
| | - Patrick Chames
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France.
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France.
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France.
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47
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Correa AMB, Guimarães JDS, Dos Santos E Alhadas E, Kushmerick C. Control of neuronal excitability by Group I metabotropic glutamate receptors. Biophys Rev 2017; 9:835-845. [PMID: 28836161 PMCID: PMC5662043 DOI: 10.1007/s12551-017-0301-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors couple through G proteins to regulate a large number of cell functions. Eight mGlu receptor isoforms have been cloned and classified into three Groups based on sequence, signal transduction mechanisms and pharmacology. This review will focus on Group I mGlu receptors, comprising the isoforms mGlu1 and mGlu5. Activation of these receptors initiates both G protein-dependent and -independent signal transduction pathways. The G-protein-dependent pathway involves mainly Gαq, which can activate PLCβ, leading initially to the formation of IP3 and diacylglycerol. IP3 can release Ca2+ from cellular stores resulting in activation of Ca2+-dependent ion channels. Intracellular Ca2+, together with diacylglycerol, activates PKC, which has many protein targets, including ion channels. Thus, activation of the G-protein-dependent pathway affects cellular excitability though several different effectors. In parallel, G protein-independent pathways lead to activation of non-selective cationic currents and metabotropic synaptic currents and potentials. Here, we provide a survey of the membrane transport proteins responsible for these electrical effects of Group I metabotropic glutamate receptors.
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Affiliation(s)
- Ana Maria Bernal Correa
- Graduate Program in Physiology and Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Christopher Kushmerick
- Graduate Program in Physiology and Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
- Departamento de Fisiologia e Biofísica - ICB, UFMG, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
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48
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Liu J, Zhang Z, Moreno-Delgado D, Dalton JA, Rovira X, Trapero A, Goudet C, Llebaria A, Giraldo J, Yuan Q, Rondard P, Huang S, Liu J, Pin JP. Allosteric control of an asymmetric transduction in a G protein-coupled receptor heterodimer. eLife 2017; 6:26985. [PMID: 28829739 PMCID: PMC5582870 DOI: 10.7554/elife.26985] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023] Open
Abstract
GPCRs play critical roles in cell communication. Although GPCRs can form heteromers, their role in signaling remains elusive. Here we used rat metabotropic glutamate (mGlu) receptors as prototypical dimers to study the functional interaction between each subunit. mGluRs can form both constitutive homo- and heterodimers. Whereas both mGlu2 and mGlu4 couple to G proteins, G protein activation is mediated by mGlu4 heptahelical domain (HD) exclusively in mGlu2-4 heterodimers. Such asymmetric transduction results from the action of both the dimeric extracellular domain, and an allosteric activation by the partially-activated non-functional mGlu2 HD. G proteins activation by mGlu2 HD occurs if either the mGlu2 HD is occupied by a positive allosteric modulator or if mGlu4 HD is inhibited by a negative modulator. These data revealed an oriented asymmetry in mGlu heterodimers that can be controlled with allosteric modulators. They provide new insight on the allosteric interaction between subunits in a GPCR dimer.
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Affiliation(s)
- Junke Liu
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Zongyong Zhang
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - David Moreno-Delgado
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - James Ar Dalton
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Barcelona, Spain.,Network Biomedical Research Center on Mental Health, Barcelona, Spain
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Ana Trapero
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Cyril Goudet
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Jesús Giraldo
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Barcelona, Spain.,Network Biomedical Research Center on Mental Health, Barcelona, Spain
| | - Qilin Yuan
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Siluo Huang
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
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Greger IH, Watson JF, Cull-Candy SG. Structural and Functional Architecture of AMPA-Type Glutamate Receptors and Their Auxiliary Proteins. Neuron 2017; 94:713-730. [DOI: 10.1016/j.neuron.2017.04.009] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 12/20/2022]
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Molecular Basis for Modulation of Metabotropic Glutamate Receptors and Their Drug Actions by Extracellular Ca 2. Int J Mol Sci 2017; 18:ijms18030672. [PMID: 28335551 PMCID: PMC5372683 DOI: 10.3390/ijms18030672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/13/2017] [Accepted: 03/17/2017] [Indexed: 12/24/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) associated with the slow phase of the glutamatergic signaling pathway in neurons of the central nervous system have gained importance as drug targets for chronic neurodegenerative diseases. While extracellular Ca2+ was reported to exhibit direct activation and modulation via an allosteric site, the identification of those binding sites was challenged by weak binding. Herein, we review the discovery of extracellular Ca2+ in regulation of mGluRs, summarize the recent developments in probing Ca2+ binding and its co-regulation of the receptor based on structural and biochemical analysis, and discuss the molecular basis for Ca2+ to regulate various classes of drug action as well as its importance as an allosteric modulator in mGluRs.
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