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Yadav P, Podia M, Kumari SP, Mani I. Glutamate receptor endocytosis and signaling in neurological conditions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:167-207. [PMID: 36813358 DOI: 10.1016/bs.pmbts.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The non-essential amino acid glutamate acts as a major excitatory neurotransmitter and plays a significant role in the central nervous system (CNS). It binds with two different types of receptors, ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs), responsible for the postsynaptic excitation of neurons. They are important for memory, neural development and communication, and learning. Endocytosis and subcellular trafficking of the receptor are essential for the regulation of receptor expression on the cell membrane and excitation of the cells. The endocytosis and trafficking of the receptor are dependent on its type, ligand, agonist, and antagonist present. This chapter discusses the types of glutamate receptors, their subtypes, and the regulation of their internalization and trafficking. The roles of glutamate receptors in neurological diseases are also briefly discussed.
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Affiliation(s)
- Prerna Yadav
- Department of Microbiology, University of Delhi, New Delhi, India
| | - Mansi Podia
- Department of Microbiology, University of Delhi, New Delhi, India
| | - Shashi Prabha Kumari
- Department of Microbiology, Ram Lal Anand College, University of Delhi, New Delhi, India
| | - Indra Mani
- Department of Microbiology, Gargi College, University of Delhi, New Delhi, India.
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2
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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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3
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Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
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4
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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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5
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Structural Basis for Activation of the Heterodimeric GABAB Receptor. J Mol Biol 2020; 432:5966-5984. [DOI: 10.1016/j.jmb.2020.09.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 09/11/2020] [Accepted: 09/29/2020] [Indexed: 12/18/2022]
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6
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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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7
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Nuemket N, Yasui N, Kusakabe Y, Nomura Y, Atsumi N, Akiyama S, Nango E, Kato Y, Kaneko MK, Takagi J, Hosotani M, Yamashita A. Structural basis for perception of diverse chemical substances by T1r taste receptors. Nat Commun 2017; 8:15530. [PMID: 28534491 PMCID: PMC5457512 DOI: 10.1038/ncomms15530] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 04/05/2017] [Indexed: 01/21/2023] Open
Abstract
The taste receptor type 1 (T1r) family perceives ‘palatable' tastes. These receptors function as T1r2-T1r3 and T1r1-T1r3 heterodimers to recognize a wide array of sweet and umami (savory) tastes in sugars and amino acids. Nonetheless, it is unclear how diverse tastes are recognized by so few receptors. Here we present crystal structures of the extracellular ligand-binding domains (LBDs), the taste recognition regions of the fish T1r2-T1r3 heterodimer, bound to different amino acids. The ligand-binding pocket in T1r2LBD is rich in aromatic residues, spacious and accommodates hydrated percepts. Biophysical studies show that this binding site is characterized by a broad yet discriminating chemical recognition, contributing for the particular trait of taste perception. In contrast, the analogous pocket in T1r3LBD is occupied by a rather loosely bound amino acid, suggesting that the T1r3 has an auxiliary role. Overall, we provide a structural basis for understanding the chemical perception of taste receptors. Nutrients taste perception is mediated by T1r receptors that discriminate specific tastes among their wide diversity. Here the authors present crystal structures of the ligand-binding domains of the fish T1r2-T1r3 receptor, providing a structural framework for its ligand recognition.
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Affiliation(s)
- Nipawan Nuemket
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan.,RIKEN SPring-8 Center, 1-1-1, Kouto, Hyogo 679-5148, Japan
| | - Norihisa Yasui
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Yuko Kusakabe
- Food Research Institute, NARO, 2-1-12, Kannondai, Tsukuba 305-8642, Japan
| | - Yukiyo Nomura
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Nanako Atsumi
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Shuji Akiyama
- Research Center of Integrative Molecular System (CIMoS), Institute for Molecular Science, National Institute of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan.,Department of Functional Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigo-Naka, Okazaki 444-8585, Japan
| | - Eriko Nango
- RIKEN SPring-8 Center, 1-1-1, Kouto, Hyogo 679-5148, Japan
| | - Yukinari Kato
- New Industry Creation Hatchery Center, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.,Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Mika K Kaneko
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Junichi Takagi
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Osaka 565-0871, Japan
| | - Maiko Hosotani
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Atsuko Yamashita
- Laboratory of Structural Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan.,RIKEN SPring-8 Center, 1-1-1, Kouto, Hyogo 679-5148, Japan
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8
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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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9
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Serebryany E, Folta-Stogniew E, Liu J, Yan ECY. Homodimerization enhances both sensitivity and dynamic range of the ligand-binding domain of type 1 metabotropic glutamate receptor. FEBS Lett 2016; 590:4308-4317. [PMID: 27800613 PMCID: PMC5154874 DOI: 10.1002/1873-3468.12473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/01/2016] [Accepted: 10/19/2016] [Indexed: 12/04/2023]
Abstract
Cooperativity in ligand binding is a key emergent property of protein oligomers. Positive cooperativity (higher affinity for subsequent binding events than for initial binding) is frequent. However, the symmetrically homodimeric ligand-binding domain (LBD) of metabotropic glutamate receptor type 1 exhibits negative cooperativity. To investigate its origin and functional significance, we measured the response to glutamate in vitro of wild-type and C140S LBD as a function of the extent of dimerization. Our results indicate that homodimerization enhances the affinity of the first, but not the second, binding site, relative to the monomer, giving the dimeric receptor both greater sensitivity and a broader dynamic range.
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Affiliation(s)
- Eugene Serebryany
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Ewa Folta-Stogniew
- W. M. Keck Foundation Biotechnology Resource Laboratory, Yale School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Jian Liu
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
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10
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Mechanism of Assembly and Cooperativity of Homomeric and Heteromeric Metabotropic Glutamate Receptors. Neuron 2016; 92:143-159. [PMID: 27641494 DOI: 10.1016/j.neuron.2016.08.036] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 08/19/2016] [Indexed: 11/23/2022]
Abstract
G protein-coupled receptors (GPCRs) mediate cellular responses to a wide variety of extracellular stimuli. GPCR dimerization may expand signaling diversity and tune functionality, but little is known about the mechanisms of subunit assembly and interaction or the signaling properties of heteromers. Using single-molecule subunit counting on class C metabotropic glutamate receptors (mGluRs), we map dimerization determinants and define a heterodimerization profile. Intersubunit fluorescence resonance energy transfer measurements reveal that interactions between ligand-binding domains control the conformational rearrangements underlying receptor activation. Selective liganding with photoswitchable tethered agonists conjugated to one or both subunits of covalently linked mGluR2 homodimers reveals that receptor activation is highly cooperative. Strikingly, this cooperativity is asymmetric in mGluR2/mGluR3 heterodimers. Our results lead to a model of cooperative activation of mGluRs that provides a framework for understanding how class C GPCRs couple extracellular binding to dimer reorganization and G protein activation.
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11
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Lindsley CW, Emmitte KA, Hopkins CR, Bridges TM, Gregory KJ, Niswender CM, Conn PJ. Practical Strategies and Concepts in GPCR Allosteric Modulator Discovery: Recent Advances with Metabotropic Glutamate Receptors. Chem Rev 2016; 116:6707-41. [PMID: 26882314 PMCID: PMC4988345 DOI: 10.1021/acs.chemrev.5b00656] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Allosteric modulation of GPCRs has initiated a new era of basic and translational discovery, filled with therapeutic promise yet fraught with caveats. Allosteric ligands stabilize unique conformations of the GPCR that afford fundamentally new receptors, capable of novel pharmacology, unprecedented subtype selectivity, and unique signal bias. This review provides a comprehensive overview of the basics of GPCR allosteric pharmacology, medicinal chemistry, drug metabolism, and validated approaches to address each of the major challenges and caveats. Then, the review narrows focus to highlight recent advances in the discovery of allosteric ligands for metabotropic glutamate receptor subtypes 1-5 and 7 (mGlu1-5,7) highlighting key concepts ("molecular switches", signal bias, heterodimers) and practical solutions to enable the development of tool compounds and clinical candidates. The review closes with a section on late-breaking new advances with allosteric ligands for other GPCRs and emerging data for endogenous allosteric modulators.
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Affiliation(s)
- Craig W. Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, Texas 76107, United States
| | - Corey R. Hopkins
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Thomas M. Bridges
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Karen J. Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville VIC 3052, Australia
| | - Colleen M. Niswender
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - P. Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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12
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Nemoto W, Yamanishi Y, Limviphuvadh V, Saito A, Toh H. GGIP: Structure and sequence-based GPCR-GPCR interaction pair predictor. Proteins 2016; 84:1224-33. [PMID: 27191053 DOI: 10.1002/prot.25071] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 04/26/2016] [Accepted: 05/09/2016] [Indexed: 01/20/2023]
Abstract
G Protein-Coupled Receptors (GPCRs) are important pharmaceutical targets. More than 30% of currently marketed pharmaceutical medicines target GPCRs. Numerous studies have reported that GPCRs function not only as monomers but also as homo- or hetero-dimers or higher-order molecular complexes. Many GPCRs exert a wide variety of molecular functions by forming specific combinations of GPCR subtypes. In addition, some GPCRs are reportedly associated with diseases. GPCR oligomerization is now recognized as an important event in various biological phenomena, and many researchers are investigating this subject. We have developed a support vector machine (SVM)-based method to predict interacting pairs for GPCR oligomerization, by integrating the structure and sequence information of GPCRs. The performance of our method was evaluated by the Receiver Operating Characteristic (ROC) curve. The corresponding area under the curve was 0.938. As far as we know, this is the only prediction method for interacting pairs among GPCRs. Our method could accelerate the analyses of these interactions, and contribute to the elucidation of the global structures of the GPCR networks in membranes. Proteins 2016; 84:1224-1233. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Wataru Nemoto
- Division of Life Science and Engineering, School of Science and Engineering, Tokyo Denki University (TDU), Ishizaka, Hatoyama-Machi, Hiki-Gun, Saitama, 350-0394, Japan.,Computational Biology Research Center (CBRC), Advanced Industrial Science and Technology (AIST), AIST Tokyo Waterfront Bio-IT Research Building, 2-4-7 Aomi, Koto-Ku, Tokyo, 135-0064, Japan
| | - Yoshihiro Yamanishi
- Medical Institute of Bioregulation (MiB), Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka, 812-8582, Japan.,Institute for Advanced Study, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
| | - Vachiranee Limviphuvadh
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, 138671, Singapore
| | - Akira Saito
- Division of Life Science and Engineering, School of Science and Engineering, Tokyo Denki University (TDU), Ishizaka, Hatoyama-Machi, Hiki-Gun, Saitama, 350-0394, Japan
| | - Hiroyuki Toh
- Computational Biology Research Center (CBRC), Advanced Industrial Science and Technology (AIST), AIST Tokyo Waterfront Bio-IT Research Building, 2-4-7 Aomi, Koto-Ku, Tokyo, 135-0064, Japan.,Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda-Shi, Hyogo, 669-1337, Japan
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13
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Chang K, Roche KW. Structural and molecular determinants regulating mGluR5 surface expression. Neuropharmacology 2016; 115:10-19. [PMID: 27211252 DOI: 10.1016/j.neuropharm.2016.04.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/29/2016] [Accepted: 04/26/2016] [Indexed: 01/29/2023]
Abstract
Trafficking of G protein-coupled receptors (GPCRs) to the plasma membrane is a pivotal process to fulfill their biological functions. Metabotropic glutamate receptors (mGluRs; mGluR1-8) are expressed throughout the CNS and are important for modulating synaptic transmission and plasticity. Group I mGluRs, including mGluR1 and mGluR5, have long intracellular C-terminal tails containing multiple protein binding domains and sites for phosphorylation and ER retention. We have now investigated some of the structural determinants for mGluR5 trafficking to the plasma membrane by studying a series of truncations and ligand binding mutants. We also take advantage of dimer formation between the extracellular domain (ECD) of mGluR5 and design an ECD based surface-binding assay to evaluate dimerization and surface expression of mGluR5 containing various truncations or point mutations. We found that the C terminus is not essential for mGluR5 surface expression. In contrast, the 7th transmembrane domain (TM7) plays a critical role in its surface expression in both heterologous cells and neurons. Furthermore, a ligand binding mutation within the ECD of mGluR5 (Y64A/T174A) that blocks ligand binding impairs both surface expression and dimerization of mGluR5 in neurons. The integrity of both the whole 7TM domain and the C- terminal tail of mGluR5 are also important for stabilizing dimerization with the ECD. Thus multiple domains regulate dimerization and trafficking of mGluR5. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Kai Chang
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C903, Bethesda, MD 20892, USA
| | - Katherine W Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C903, Bethesda, MD 20892, USA.
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14
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Sevastyanova TN, Kammermeier PJ. Cooperative signaling between homodimers of metabotropic glutamate receptors 1 and 5. Mol Pharmacol 2014; 86:492-504. [PMID: 25113912 DOI: 10.1124/mol.114.093468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) function as dimers. Recent work suggests that mGluR1 and mGluR5 may physically interact, but the nature and functional consequences of this relationship have not been addressed. In this study, the functional and pharmacological consequences of this interaction were investigated. Using heterologous expression of mGluR cDNA in rat sympathetic neurons from the superior cervical ganglion and inhibition of the native calcium currents as an assay for receptor activation, a functional interdependence between mGluR1 and mGluR5 was demonstrated. In neurons coexpressing these receptors, combining a selective mGluR1 competitive antagonist with either an mGluR1- or mGluR5-selective negative allosteric modulator (NAM) BAY36-7620 [(3aS,6aS)-hexahydro-5-methylene-6a-(2-naphthalenylmethyl)-1H-cyclopenta[c]furan-1-one] or MPEP [2-methyl-6-(phenylethynyl)pyridine hydrochloride], respectively, strongly occluded signaling by both receptors to an approximately equal degree. By contrast, in cells coexpressing mGluR1 and mGluR2, combining the same mGluR1 competitive inhibitor with an mGluR1 or mGluR2 NAM yielded partial and full inhibition of the response, respectively, as expected for independently acting receptors. In neurons expressing mGluR1 and mGluR5, the selective NAMs each strongly inhibited the response to glutamate, suggesting that these receptors do not interact as heterodimers, which would not be inhibited by selective NAMs. Finally, evidence for a similar mGluR1/mGluR5 functional dependence is shown in medium spiny striatal neurons. Together, these data demonstrate cooperative signaling between mGluR1 and mGluR5 in a manner inconsistent with heterodimerization, and thus suggest an interaction between homodimers.
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Affiliation(s)
- Tatyana N Sevastyanova
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
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15
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Distinct human and mouse membrane trafficking systems for sweet taste receptors T1r2 and T1r3. PLoS One 2014; 9:e100425. [PMID: 25029362 PMCID: PMC4100762 DOI: 10.1371/journal.pone.0100425] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/27/2014] [Indexed: 11/23/2022] Open
Abstract
The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system.
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Jones GN, Moschidou D, Abdulrazzak H, Kalirai BS, Vanleene M, Osatis S, Shefelbine SJ, Horwood NJ, Marenzana M, De Coppi P, Bassett JD, Williams GR, Fisk NM, Guillot PV. Potential of human fetal chorionic stem cells for the treatment of osteogenesis imperfecta. Stem Cells Dev 2014; 23:262-76. [PMID: 24028330 PMCID: PMC3904514 DOI: 10.1089/scd.2013.0132] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 09/12/2013] [Indexed: 12/13/2022] Open
Abstract
Osteogenesis imperfecta (OI) is a genetic bone pathology with prenatal onset, characterized by brittle bones in response to abnormal collagen composition. There is presently no cure for OI. We previously showed that human first trimester fetal blood mesenchymal stem cells (MSCs) transplanted into a murine OI model (oim mice) improved the phenotype. However, the clinical use of fetal MSC is constrained by their limited number and low availability. In contrast, human fetal early chorionic stem cells (e-CSC) can be used without ethical restrictions and isolated in high numbers from the placenta during ongoing pregnancy. Here, we show that intraperitoneal injection of e-CSC in oim neonates reduced fractures, increased bone ductility and bone volume (BV), increased the numbers of hypertrophic chondrocytes, and upregulated endogenous genes involved in endochondral and intramembranous ossification. Exogenous cells preferentially homed to long bone epiphyses, expressed osteoblast genes, and produced collagen COL1A2. Together, our data suggest that exogenous cells decrease bone brittleness and BV by directly differentiating to osteoblasts and indirectly stimulating host chondrogenesis and osteogenesis. In conclusion, the placenta is a practical source of stem cells for the treatment of OI.
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Affiliation(s)
- Gemma N. Jones
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Dafni Moschidou
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Hassan Abdulrazzak
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Bhalraj Singh Kalirai
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Maximilien Vanleene
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Suchaya Osatis
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | | | - Nicole J. Horwood
- Kennedy Institute of Rheumatology, Imperial College London, London, United Kingdom
| | - Massimo Marenzana
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Paolo De Coppi
- Surgery Unit, UCL Institute of Child Health, London, United Kingdom
| | - J.H. Duncan Bassett
- Molecular Endocrinology Group, Department of Medicine, Imperial College London, London, United Kingdom
| | - Graham R. Williams
- Molecular Endocrinology Group, Department of Medicine, Imperial College London, London, United Kingdom
| | - Nicholas M. Fisk
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Australia
| | - Pascale V. Guillot
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
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17
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Geng Y, Bush M, Mosyak L, Wang F, Fan QR. Structural mechanism of ligand activation in human GABA(B) receptor. Nature 2013; 504:254-9. [PMID: 24305054 PMCID: PMC3865065 DOI: 10.1038/nature12725] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 09/30/2013] [Indexed: 01/02/2023]
Abstract
Human GABA(B) (γ-aminobutyric acid class B) receptor is a G-protein-coupled receptor central to inhibitory neurotransmission in the brain. It functions as an obligatory heterodimer of the subunits GBR1 and GBR2. Here we present the crystal structures of a heterodimeric complex between the extracellular domains of GBR1 and GBR2 in the apo, agonist-bound and antagonist-bound forms. The apo and antagonist-bound structures represent the resting state of the receptor; the agonist-bound complex corresponds to the active state. Both subunits adopt an open conformation at rest, and only GBR1 closes on agonist-induced receptor activation. The agonists and antagonists are anchored in the interdomain crevice of GBR1 by an overlapping set of residues. An antagonist confines GBR1 to the open conformation of the inactive state, whereas an agonist induces its domain closure for activation. Our data reveal a unique activation mechanism for GABA(B) receptor that involves the formation of a novel heterodimer interface between subunits.
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Affiliation(s)
- Yong Geng
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
| | - Martin Bush
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
| | - Lidia Mosyak
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
| | - Feng Wang
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
| | - Qing R Fan
- 1] Department of Pharmacology, Columbia University, New York, New York 10032, USA [2] Department of Pathology & Cell Biology, Columbia University, New York, New York 10032, USA
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18
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Rivero-Müller A, Jonas KC, Hanyaloglu AC, Huhtaniemi I. Di/Oligomerization of GPCRs—Mechanisms and Functional Significance. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:163-85. [DOI: 10.1016/b978-0-12-386931-9.00007-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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19
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Moreno JL, Holloway T, González-Maeso J. G protein-coupled receptor heterocomplexes in neuropsychiatric disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:187-205. [PMID: 23663970 DOI: 10.1016/b978-0-12-386931-9.00008-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
G protein-coupled receptors (or GPCRs) represent the largest family of membrane proteins in the human genome and are the target of approximately half of all therapeutic drugs. GPCRs contain a conserved structure of seven transmembrane domains. Their amino terminus is located extracellularly, whereas the carboxy terminus extends into the cytoplasm. Accumulating evidence suggests that GPCRs exist and function as monomeric entities. Nevertheless, more recent findings indicate that GPCRs can also form dimers or even higher order oligomers. The differential pharmacological and signaling properties of GPCR heteromeric complexes hint that their physiological effects may be different as compared to those obtained in tissue cultures that express a particular GPCR. In this chapter, we review current data on the role of GPCR heteromerization in receptor signaling, as well as its potential implication in neuropsychiatric disorders such as schizophrenia, depression, and Parkinson's disease.
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Affiliation(s)
- José L Moreno
- Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, USA
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20
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Moreno JL, Muguruza C, Umali A, Mortillo S, Holloway T, Pilar-Cuéllar F, Mocci G, Seto J, Callado LF, Neve RL, Milligan G, Sealfon SC, López-Giménez JF, Meana JJ, Benson DL, González-Maeso J. Identification of three residues essential for 5-hydroxytryptamine 2A-metabotropic glutamate 2 (5-HT2A·mGlu2) receptor heteromerization and its psychoactive behavioral function. J Biol Chem 2012; 287:44301-19. [PMID: 23129762 DOI: 10.1074/jbc.m112.413161] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Serotonin and glutamate G protein-coupled receptor (GPCR) neurotransmission affects cognition and perception in humans and rodents. GPCRs are capable of forming heteromeric complexes that differentially alter cell signaling, but the role of this structural arrangement in modulating behavior remains unknown. Here, we identified three residues located at the intracellular end of transmembrane domain four that are necessary for the metabotropic glutamate 2 (mGlu2) receptor to be assembled as a GPCR heteromer with the serotonin 5-hydroxytryptamine 2A (5-HT(2A)) receptor in the mouse frontal cortex. Substitution of these residues (Ala-677(4.40), Ala-681(4.44), and Ala-685(4.48)) leads to absence of 5-HT(2A)·mGlu2 receptor complex formation, an effect that is associated with a decrease in their heteromeric ligand binding interaction. Disruption of heteromeric expression with mGlu2 attenuates the psychosis-like effects induced in mice by hallucinogenic 5-HT(2A) agonists. Furthermore, the ligand binding interaction between the components of the 5-HT(2A)·mGlu2 receptor heterocomplex is up-regulated in the frontal cortex of schizophrenic subjects as compared with controls. Together, these findings provide structural evidence for the unique behavioral function of a GPCR heteromer.
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Affiliation(s)
- José L Moreno
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, USA
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21
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Geng Y, Xiong D, Mosyak L, Malito DL, Kniazeff J, Chen Y, Burmakina S, Quick M, Bush M, Javitch JA, Pin JP, Fan QR. Structure and functional interaction of the extracellular domain of human GABA(B) receptor GBR2. Nat Neurosci 2012; 15:970-8. [PMID: 22660477 PMCID: PMC3374333 DOI: 10.1038/nn.3133] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/10/2012] [Indexed: 11/08/2022]
Abstract
Inhibitory neurotransmission is mediated primarily by GABA. The metabotropic GABA(B) receptor is a G protein-coupled receptor central to mammalian brain function. Malfunction of GABA(B) receptor has been implicated in several neurological disorders. GABA(B) receptor functions as a heterodimeric assembly of GBR1 and GBR2 subunits, where GBR1 is responsible for ligand-binding and GBR2 is responsible for G protein coupling. Here we demonstrate that the GBR2 ectodomain directly interacts with the GBR1 ectodomain to increase agonist affinity by selectively stabilizing the agonist-bound conformation of GBR1. We present the crystal structure of the GBR2 ectodomain, which reveals a polar heterodimeric interface. We also identify specific heterodimer contacts from both subunits, and GBR1 residues involved in ligand recognition. Lastly, our structural and functional data indicate that the GBR2 ectodomain adopts a constitutively open conformation, suggesting a structural asymmetry in the active state of GABA(B) receptor that is unique to the GABAergic system.
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Affiliation(s)
- Yong Geng
- Department of Pharmacology, Columbia University, New York, New York, USA
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22
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Maîtrepierre E, Sigoillot M, Le Pessot L, Briand L. Recombinant expression, in vitro refolding, and biophysical characterization of the N-terminal domain of T1R3 taste receptor. Protein Expr Purif 2012; 83:75-83. [PMID: 22450161 DOI: 10.1016/j.pep.2012.03.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/28/2012] [Accepted: 03/12/2012] [Indexed: 11/19/2022]
Abstract
The sweet taste receptor is a heterodimeric receptor composed of the T1R2 and T1R3 subunits, while T1R1 and T1R3 assemble to form the umami taste receptor. T1R receptors belong to the family of class C G-protein coupled receptors (GPCRs). In addition to a transmembrane heptahelical domain, class C GPCRs have a large extracellular N-terminal domain (NTD), which is the primary ligand-binding site. The T1R2 and T1R1 subunits have been shown to be responsible for ligand binding, via their NTDs. However, little is known about the contribution of T1R3-NTD to receptor functions. To enable biophysical characterization, we overexpressed the human NTD of T1R3 (hT1R3-NTD) using Escherichia coli in the form of inclusion bodies. Using a fractional factorial screen coupled to a functional assay, conditions were determined for the refolding of hT1R3-NTD. Far-UV circular dichroism spectroscopic studies revealed that hT1R3-NTD was well refolded. Using size-exclusion chromatography, we found that the refolded protein behaves as a dimer. Ligand binding quantified by tryptophan fluorescence quenching and microcalorimetry showed that hT1R3-NTD is functional and capable of binding sucralose with an affinity in the millimolar range. This study also provides a strategy to produce functional hT1R3-NTD by heterologous expression in E. coli; this is a prerequisite for structural determination and functional analysis of ligand-binding regions of other class C GPCRs.
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Affiliation(s)
- Elodie Maîtrepierre
- Centre des Sciences du Goût et de l'Alimentation, UMR6265 CNRS, UMR1324 INRA, Université de Bourgogne, F-21000 Dijon, France
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23
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Abstract
The G-protein-coupled receptors (GPCRs) are one of the largest super families of cell-surface receptors and play crucial roles in virtually every organ system. One particular family of GPCRs, the class C GPCRs, is distinguished by a characteristically large extracellular domain and constitutive dimerization. The structure and activation mechanism of this family result in potentially unique ligand recognition sites, thereby offering a variety of possibilities by which receptor activity might be modulated using novel compounds. In the present article, we aim to provide an overview of the exact sites and structural features involved in ligand recognition of the class C GPCRs. Furthermore, we demonstrate the precise steps that occur during the receptor activation process, which underlie the possibilities by which receptor function may be altered by different approaches. Finally, we use four typical family members to illustrate orthosteric and allosteric sites with representative ligands and their corresponding therapeutic potential.
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24
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Taman A, Ribeiro P. Characterization of a truncated metabotropic glutamate receptor in a primitive metazoan, the parasitic flatworm Schistosoma mansoni. PLoS One 2011; 6:e27119. [PMID: 22069494 PMCID: PMC3206071 DOI: 10.1371/journal.pone.0027119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 10/11/2011] [Indexed: 11/26/2022] Open
Abstract
A novel glutamate-binding protein was identified in Schistosoma mansoni. The protein (SmGBP) is related to metabotropic glutamate receptors from other species and has a predicted glutamate binding site located within a Venus Flytrap module but it lacks the heptahelical transmembrane segment that normally characterizes these receptors. The SmGBP cDNA was cloned, verified by 5' and 3' Rapid Amplification of cDNA Ends (RACE) and shown to be polyadenylated at the 3'end, suggesting the transcript is full-length. The cloned cDNA was subsequently expressed in bacteria and shown to encode a functional glutamate-binding protein. Other studies, using a specific peptide antibody, determined that SmGBP exists in two forms, a monomer of the expected size and a stable but non-covalent dimer. The monomer and dimer are both present in the membrane fraction of S. mansoni and are resistant to extraction with high-salt, alkaline pH and urea, suggesting SmGBP is either an integral membrane protein or a peripheral protein that is tightly associated with the membrane. Surface biotinylation experiments combined with western blot analyses and confocal immunolocalization revealed that SmGBP localized to the surface membranes of adult male schistosomes, especially the dorsal tubercles. In contrast, we detected little or no expression of SmGBP either in the females or larval stages. A comparative quantitative PCR analysis confirmed that the level of SmGBP expression is several-fold higher in male worms than cercariae, and it is barely detectable in adult females. Together, the results identify SmGBP as a new type of schistosome glutamate receptor that is both gender- and stage-specific. The high-level expression of this protein in the male tubercles suggests a possible role in host-parasite interaction.
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Affiliation(s)
- Amira Taman
- Institute of Parasitology, McGill University, Macdonald Campus, Sainte Anne de Bellevue, Quebec, Canada
| | - Paula Ribeiro
- Institute of Parasitology, McGill University, Macdonald Campus, Sainte Anne de Bellevue, Quebec, Canada
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25
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Prézeau L, Rondard P, Goudet C, Kniazeff J, Pin JP. Class C receptor activation mechanisms illustrated by mGlu and GABAB receptors. A review. FLAVOUR FRAG J 2011. [DOI: 10.1002/ffj.2044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laurent Prézeau
- CNRS, UMR 5203; Institut de Génomique Fonctionnelle, INSERM, U661, and Université Montpellier 1, 2; Montpellier; F-34000; France
| | - Philippe Rondard
- CNRS, UMR 5203; Institut de Génomique Fonctionnelle, INSERM, U661, and Université Montpellier 1, 2; Montpellier; F-34000; France
| | - Cyril Goudet
- CNRS, UMR 5203; Institut de Génomique Fonctionnelle, INSERM, U661, and Université Montpellier 1, 2; Montpellier; F-34000; France
| | - Julie Kniazeff
- CNRS, UMR 5203; Institut de Génomique Fonctionnelle, INSERM, U661, and Université Montpellier 1, 2; Montpellier; F-34000; France
| | - Jean-Philippe Pin
- CNRS, UMR 5203; Institut de Génomique Fonctionnelle, INSERM, U661, and Université Montpellier 1, 2; Montpellier; F-34000; France
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26
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Tateyama M, Kubo Y. The intra-molecular activation mechanisms of the dimeric metabotropic glutamate receptor 1 differ depending on the type of G proteins. Neuropharmacology 2011; 61:832-41. [PMID: 21672544 DOI: 10.1016/j.neuropharm.2011.05.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 05/19/2011] [Accepted: 05/25/2011] [Indexed: 11/19/2022]
Abstract
Metabotropic glutamate receptor 1 (mGlu1) functions as a homodimer and activates not only the Gq but also the Gi/o and Gs pathways. Because of the dimeric configuration, different pathways could be activated either through the glutamate-bound subunit (cis-activation) and/or the other one (trans-activation). We here examined whether the intra-molecular activation mechanisms in the mGlu1 differ depending on the type of coupling G proteins, using various combinations of mGlu1 constructs that lack glutamate binding and/or G-protein coupling. The cis- or trans-activation alone was confirmed to trigger the Gq-coupled intracellular Ca(2+) transient. In contrast, the Gi/o-coupled G protein-dependent inward rectifying potassium (GIRK) channels were not activated either through the cis- or trans-activation alone. When one subunit of dimeric mGlu1 lacked the G-protein coupling, a significant decrease in the glutamate-induced GIRK current density was also observed. As the G protein-coupling-deficient subunit did not decrease the cell surface expression of mGlu1 and the Gq-coupled Ca(2+) transient, it was suggested that the coupling deficiency in one subunit of mGlu1 attenuates the Gi/o but not Gq coupling. In conclusion, multiple G-protein signaling was differentially activated by different intra-molecular activation mechanisms of the dimeric mGlu1.
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Affiliation(s)
- Michihiro Tateyama
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan.
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27
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Guidolin D, Ciruela F, Genedani S, Guescini M, Tortorella C, Albertin G, Fuxe K, Agnati LF. Bioinformatics and mathematical modelling in the study of receptor–receptor interactions and receptor oligomerization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1267-83. [DOI: 10.1016/j.bbamem.2010.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/31/2010] [Accepted: 09/26/2010] [Indexed: 10/19/2022]
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Rondard P, Goudet C, Kniazeff J, Pin JP, Prézeau L. The complexity of their activation mechanism opens new possibilities for the modulation of mGlu and GABAB class C G protein-coupled receptors. Neuropharmacology 2010; 60:82-92. [PMID: 20713070 DOI: 10.1016/j.neuropharm.2010.08.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/30/2010] [Accepted: 08/06/2010] [Indexed: 12/24/2022]
Abstract
In the human genome, 22 genes are coding for the class C G protein-coupled receptors that are receptors for the two main neurotransmitters glutamate and γ-aminobutyric acid, for Ca(2+) and for sweet and amino acid taste compounds. In addition to the GPCR heptahelical transmembrane domain responsible for G-protein activation, class C receptors possess a large extracellular domain that is responsible for ligand recognition. Recent studies had revealed that class C receptors are homo- or heterodimers with unique mechanism of activation. In the present review, we present an up-to-date view of the structures and activation mechanism of these receptors in particular the metabotropic glutamate and GABA(B) receptors. We show how the complexity of functioning of these transmembrane proteins can be used for the development of therapeutics to modulate their activity. We emphasize on the new approaches and drugs that could potentially become important in the future pharmacology of these receptors.
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29
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Wellendorph P, Bräuner-Osborne H. Molecular basis for amino acid sensing by family C G-protein-coupled receptors. Br J Pharmacol 2009; 156:869-84. [PMID: 19298394 DOI: 10.1111/j.1476-5381.2008.00078.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Family C of human G-protein-coupled receptors (GPCRs) is constituted by eight metabotropic glutamate receptors, two gamma-aminobutyric acid type B (GABA(B1-2)) subunits forming the heterodimeric GABA(B) receptor, the calcium-sensing receptor, three taste1 receptors (T1R1-3), a promiscuous L-alpha;-amino acid receptor G-protein-coupled receptor family C, group 6, subtype A (GPRC6A) and seven orphan receptors. Aside from the orphan receptors, the family C GPCRs are dimeric receptors characterized by a large extracellular Venus flytrap domain which bind the endogenous agonists. Except from the GABA(B1-2) and T1R2-3 receptor, all receptors are either activated or positively modulated by amino acids. In this review, we outline mutational, biophysical and structural studies which have elucidated the interaction of the amino acids with the Venus flytrap domains, molecular mechanisms of receptor selectivity and the initial steps in receptor activation.
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Affiliation(s)
- P Wellendorph
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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30
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Ferraguti F, Crepaldi L, Nicoletti F. Metabotropic glutamate 1 receptor: current concepts and perspectives. Pharmacol Rev 2009; 60:536-81. [PMID: 19112153 DOI: 10.1124/pr.108.000166] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Almost 25 years after the first report that glutamate can activate receptors coupled to heterotrimeric G-proteins, tremendous progress has been made in the field of metabotropic glutamate receptors. Now, eight members of this family of glutamate receptors, encoded by eight different genes that share distinctive structural features have been identified. The first cloned receptor, the metabotropic glutamate (mGlu) receptor mGlu1 has probably been the most extensively studied mGlu receptor, and in many respects it represents a prototypical subtype for this family of receptors. Its biochemical, anatomical, physiological, and pharmacological characteristics have been intensely investigated. Together with subtype 5, mGlu1 receptors constitute a subgroup of receptors that couple to phospholipase C and mobilize Ca(2+) from intracellular stores. Several alternatively spliced variants of mGlu1 receptors, which differ primarily in the length of their C-terminal domain and anatomical localization, have been reported. Use of a number of genetic approaches and the recent development of selective antagonists have provided a means for clarifying the role played by this receptor in a number of neuronal systems. In this article we discuss recent advancements in the pharmacology and concepts about the intracellular transduction and pathophysiological role of mGlu1 receptors and review earlier data in view of these novel findings. The impact that this new and better understanding of the specific role of these receptors may have on novel treatment strategies for a variety of neurological and psychiatric disorders is considered.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, Innsbruck A-6020, Austria.
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31
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Park PSH, Lodowski DT, Palczewski K. Activation of G protein-coupled receptors: beyond two-state models and tertiary conformational changes. Annu Rev Pharmacol Toxicol 2008; 48:107-41. [PMID: 17848137 PMCID: PMC2639654 DOI: 10.1146/annurev.pharmtox.48.113006.094630] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transformation of G protein-coupled receptors (GPCRs) from a quiescent to an active state initiates signal transduction. All GPCRs share a common architecture comprising seven transmembrane-spanning alpha-helices, which accommodates signal propagation from a diverse repertoire of external stimuli across biological membranes to a heterotrimeric G protein. Signal propagation through the transmembrane helices likely involves mechanistic features common to all GPCRs. The structure of the light receptor rhodopsin may serve as a prototype for the transmembrane architecture of GPCRs. Early biochemical, biophysical, and pharmacological studies led to the conceptualization of receptor activation based on the context of two-state equilibrium models and conformational changes in protein structure. More recent studies indicate a need to move beyond these classical paradigms and to consider additional aspects of the molecular character of GPCRs, such as the oligomerization and dynamics of the receptor.
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Affiliation(s)
- Paul S-H Park
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
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Remelli R, Robbins MJ, McIlhinney RAJ. The C-terminus of the metabotropic glutamate receptor 1b regulates dimerization of the receptor. J Neurochem 2008; 104:1020-31. [DOI: 10.1111/j.1471-4159.2007.05034.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Impoverished rearing impairs working memory and metabotropic glutamate receptor 5 expression. Neuroreport 2008; 19:239-43. [DOI: 10.1097/wnr.0b013e3282f4aa15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hu J, Spiegel AM. Structure and function of the human calcium-sensing receptor: insights from natural and engineered mutations and allosteric modulators. J Cell Mol Med 2008; 11:908-22. [PMID: 17979873 PMCID: PMC4401263 DOI: 10.1111/j.1582-4934.2007.00096.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The human extracellular Ca(2+)-sensing receptor (CaR), a member of the G protein-coupled receptor family 3, plays a key role in the regulation of extracellular calcium homeostasis. It is one of just a few G protein-coupled receptors with a large number of naturally occurring mutations identified in patients. In contrast to the small sizes of its agonists, this large dimeric receptor consists of domains with topologically distinctive orthosteric and allosteric sites. Information derived from studies of naturally occurring mutations, engineered mutations, allosteric modulators and crystal structures of the agonist-binding domain of homologous type 1 metabotropic glutamate receptor and G protein-coupled rhodopsin offers new insights into the structure and function of the CaR.
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Affiliation(s)
- Jianxin Hu
- Molecular Signalling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Nomura R, Suzuki Y, Kakizuka A, Jingami H. Direct detection of the interaction between recombinant soluble extracellular regions in the heterodimeric metabotropic gamma-aminobutyric acid receptor. J Biol Chem 2007; 283:4665-73. [PMID: 18165688 DOI: 10.1074/jbc.m705202200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gamma-aminobutyric acid, type B (GABAB) receptor is a heterodimeric receptor consisting of two complementary subunits, GABAB1 receptor (GBR1) and GABAB2 receptor (GBR2). GBR1 is responsible for GABA binding, whereas GBR2 is considered to perform a critical role in signal transduction toward downstream targets. Therefore, precise communication between GBR1 and GBR2 is thought to be essential for the proper signal transduction process. However, biochemical data describing the interaction of the two subunits, especially for the extracellular regions, are not sufficient. Thus we began by developing a protein expression system of the soluble extracellular regions. One of the soluble recombinant GBR1 proteins exhibited a ligand binding ability, which is similar to that of the full-length GBR1, and thus the ligand-binding domain was determined. Direct interaction between GBR1 and GBR2 extracellular soluble fragments was confirmed by co-expression followed by affinity column chromatography and a sucrose density gradient sedimentation. In addition, we also found homo-oligomeric states of these soluble extracellular regions. The interaction between the two soluble extracellular regions caused the enhancement of the agonist affinity for GBR1 as previously reported in a cell-based assay. These results not only open the way to future structural studies but also highlight the role of the interaction between the extracellular regions, which controls agonist affinity to the heterodimeric receptor.
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Affiliation(s)
- Rei Nomura
- Department of Molecular Biology, Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
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Tang EHC, Jensen BL, Skott O, Leung GPH, Feletou M, Man RYK, Vanhoutte PM. The role of prostaglandin E and thromboxane-prostanoid receptors in the response to prostaglandin E2 in the aorta of Wistar Kyoto rats and spontaneously hypertensive rats. Cardiovasc Res 2007; 78:130-8. [PMID: 18093985 DOI: 10.1093/cvr/cvm112] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The present study examined the hypothesis that prostaglandin E2 (PGE2) through activation of prostaglandin E (EP) receptor contributes to endothelium-dependent contractions. METHODS AND RESULTS Western blotting revealed that the protein expression of EP1 receptor was significantly down-regulated in the aorta of the spontaneously hypertensive rat (SHR), but there was no significant difference in the expression of EP2, EP4, and total EP3 receptors between preparations of Wistar Kyoto rats (WKY) and SHR. Isometric tension studies showed that low concentrations of PGE2 caused endothelium-dependent relaxations in WKY but not in aortas of the SHR. High concentrations of PGE2 evoked contractions predominately through the activation of thromboxane-prostanoid (TP) receptors in the WKY, but involves the dual activation EP and TP receptors in the SHR. SQ29,548, BAYu3405 and Terutroban (TP receptor antagonists), and AH6809 (non-selective EP receptor antagonist) abolished, while SC19220 (preferential EP1 receptor antagonist) did not inhibit endothelium-dependent contractions. Both SC19220 and AH6809 significantly inhibited contractions to U46619 (TP receptor agonist). CONCLUSION The present study demonstrates that the contraction caused by PGE2 in the SHR aorta is dependent on the activation of EP1 and TP receptors, but that endothelium-dependent contractions do not require the former. Thus, PGE2 is unlikely to be an endothelium-derived contracting factor in this artery. The ability of AH6809 to inhibit endothelium-dependent contractions can be attributed to its partial antagonism at TP receptors. Nevertheless, the impairment of PGE2-mediated relaxation may contribute to endothelial dysfunction in the aorta of the SHR.
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Affiliation(s)
- Eva H C Tang
- Department of Pharmacology, The University of Hong Kong, 2/F, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong
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Corti C, Crepaldi L, Mion S, Roth AL, Xuereb JH, Ferraguti F. Altered dimerization of metabotropic glutamate receptor 3 in schizophrenia. Biol Psychiatry 2007; 62:747-55. [PMID: 17531207 DOI: 10.1016/j.biopsych.2006.12.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/30/2006] [Accepted: 12/07/2006] [Indexed: 11/20/2022]
Abstract
BACKGROUND Metabotropic glutamate receptors (mGlus) may be involved in the pathophysiology of schizophrenia. Group II mGlus (mGlu2 and mGlu3) have attracted considerable interest since the development of potent specific agonists that exhibit atypical antipsychotic-like activity and reports of a genetic association between the mGlu3 gene and schizophrenia. METHODS In this postmortem study, mGlu3 protein levels in Brodmann area 10 of prefrontal cortex from schizophrenic (n = 20) and control (n = 35) subjects were analyzed by western immunoblotting using a novel specific mGlu3 antibody and an antibody for the vesicular glutamate transporter 1 (VGluT1). RESULTS We report a significant decrease in the dimeric/oligomeric forms of mGlu3 in schizophrenic patients compared with control subjects, whereas total mGlu3 and VGluT1 levels were not altered significantly. CONCLUSIONS This is the first experimental evidence that mGlu3 receptor levels are altered in schizophrenia and supports the hypothesis that neurotransmission involving this particular excitatory amino acid receptor is impaired in schizophrenia.
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Affiliation(s)
- Corrado Corti
- Department of Biology, Psychiatry Centre of Excellence in Drug Discovery, GlaxoSmithKline Medicines Research Centre, Verona, Italy.
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38
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Zeitz C, Forster U, Neidhardt J, Feil S, Kälin S, Leifert D, Flor PJ, Berger W. Night blindness-associated mutations in the ligand-binding, cysteine-rich, and intracellular domains of the metabotropic glutamate receptor 6 abolish protein trafficking. Hum Mutat 2007; 28:771-80. [PMID: 17405131 DOI: 10.1002/humu.20499] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mutations in the GRM6 gene, which encodes the metabotropic glutamate receptor 6 (mGluR6), lead to autosomal recessive congenital stationary night blindness (CSNB), which is characterized by loss of night vision due to a defect in signal transmission from photoreceptor to the adjacent ON-bipolar cells in the retina. So far, the sequence variations that have been described in six different families include nonsense, frameshift, and missense mutations. Here we investigated the impact of missense mutations in the ligand-binding domain, a conserved cysteine-rich domain, and the intracellular domain on the localization of the protein. We visualized and discriminated between surface and intracellular protein. Here we demonstrate that the wild-type (wt) protein localizes to the cell surface, and to endoplasmic reticulum (ER) and Golgi compartments. This also holds true for a mGluR6 variant containing a polymorphic, nondisease-associated amino acid exchange in the ligand-binding domain. In contrast, all disease-associated missense mutations lead to retention of the protein in the ER, while dimerization seems not to be affected. This is the first report that shows that CSNB-associated mutations in three different domains of mGluR6 abolish proper protein trafficking. We propose that the ligand-binding and the poorly characterized cysteine-rich domains, in addition to the intracellular domains, have a pivotal role in correct trafficking of metabotropic glutamate receptors to the cell surface.
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Affiliation(s)
- Christina Zeitz
- Institute of Medical Genetics, Division of Medical Molecular Genetics and Gene Diagnostics, University of Zurich, Zurich, Switzerland.
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Muto T, Tsuchiya D, Morikawa K, Jingami H. Expression, purification, crystallization and preliminary X-ray analysis of the ligand-binding domain of metabotropic glutamate receptor 7. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:627-30. [PMID: 17620729 PMCID: PMC2335145 DOI: 10.1107/s1744309107030059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 06/20/2007] [Indexed: 11/10/2022]
Abstract
Glutamate is the major excitatory neurotransmitter and its metabotropic glutamate receptor (mGluR) plays an important role in the central nervous system. The ligand-binding domain (LBD) of mGluR subtype 7 (mGluR7) was produced using the baculovirus expression system and purified from the culture medium. The purified protein was characterized by gel-filtration chromatography, SDS-PAGE and a ligand-binding assay. Crystals of mGluR7 LBD were grown at 293 K by the hanging-drop vapour-diffusion method. The crystals diffracted X-rays to 3.30 A resolution using synchrotron radiation and belong to the trigonal space group P3(1)21, with unit-cell parameters a = b = 92.4, c = 114.3 A. Assuming the presence of one protomer per crystallographic asymmetric unit, the Matthews coefficient V(M) was calculated to be 2.5 A3 Da(-1) and the solvent content was 51%.
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Affiliation(s)
- Takanori Muto
- Biomolecular Engineering Research Institute, Suita, Osaka 565-0874, Japan
| | - Daisuke Tsuchiya
- Biomolecular Engineering Research Institute, Suita, Osaka 565-0874, Japan
| | - Kosuke Morikawa
- Biomolecular Engineering Research Institute, Suita, Osaka 565-0874, Japan
| | - Hisato Jingami
- Biomolecular Engineering Research Institute, Suita, Osaka 565-0874, Japan
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40
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Schkeryantz JM, Kingston AE, Johnson MP. Prospects for metabotropic glutamate 1 receptor antagonists in the treatment of neuropathic pain. J Med Chem 2007; 50:2563-8. [PMID: 17489573 DOI: 10.1021/jm060950g] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeffrey M Schkeryantz
- Lilly Research Labs, Eli Lilly & Co., Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
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41
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Sugi T, Oyama T, Muto T, Nakanishi S, Morikawa K, Jingami H. Crystal structures of autoinhibitory PDZ domain of Tamalin: implications for metabotropic glutamate receptor trafficking regulation. EMBO J 2007; 26:2192-205. [PMID: 17396155 PMCID: PMC1852777 DOI: 10.1038/sj.emboj.7601651] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 02/23/2007] [Indexed: 11/09/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) function as neuronal G-protein-coupled receptors and this requires efficient membrane targeting through associations with cytoplasmic proteins. However, the molecular mechanism regulating mGluR cell-surface trafficking remains unknown. We report here that mGluR trafficking is controlled by the autoregulatory assembly of a scaffold protein Tamalin. In the absence of mGluR, Tamalin self-assembles into autoinhibited conformations, through its PDZ domain and C-terminal intrinsic ligand motif. X-ray crystallographic analyses visualized integral parts of the oligomeric self-assemblies of Tamalin, which require not only the novel hydrophobic dimerization interface but also canonical and noncanonical PDZ/ligand autoinhibitory interactions. The mGluR cytoplasmic region can competitively bind to Tamalin at a higher concentration, disrupting weak inhibitory interactions. The atomic view of mGluR association suggests that this rearrangement is dominated by electrostatic attraction and repulsion. We also observed in mammalian cells that the association liberates the intrinsic ligand toward a motor protein receptor, thereby facilitating mGluR cell-surface trafficking. Our study suggests a novel regulatory mechanism of the PDZ domain, by which Tamalin switches between the trafficking-inhibited and -active forms depending on mGluR association.
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Affiliation(s)
- Takuma Sugi
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
| | - Takuji Oyama
- Department of Structural Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
| | - Takanori Muto
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Fuji Gotemba Research Laboratories, Chugai Pharmaceutical Co., Ltd, 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan
| | | | - Kosuke Morikawa
- Department of Structural Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
- Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan. Tel.: +81 6 6872 8201; Fax: +81 6 6872 19. E-mail:
| | - Hisato Jingami
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Office of Graduate Courses for Integrated Research Training, Kyoto University Faculty of Medicine, Yoshida, Sakyo-Ku, Kyoto 606-8501, Japan
- Office of Graduate Courses for Integrated Research Training, Kyoto University, Yoshida-Konoe, Sakyo-Ku, Kyoto 606-8501, Japan. Tel.: +81 75 753 9493; Fax: +81 75 753 9495. E-mail:
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Muto T, Tsuchiya D, Morikawa K, Jingami H. Structures of the extracellular regions of the group II/III metabotropic glutamate receptors. Proc Natl Acad Sci U S A 2007; 104:3759-64. [PMID: 17360426 PMCID: PMC1820657 DOI: 10.1073/pnas.0611577104] [Citation(s) in RCA: 302] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metabotropic glutamate receptors play major roles in the activation of excitatory synapses in the central nerve system. We determined the crystal structure of the entire extracellular region of the group II receptor and that of the ligand-binding region of the group III receptor. A comparison among groups I, II, and III provides the structural basis that could account for the discrimination of group-specific agonists. Furthermore, the structure of group II includes the cysteine-rich domain, which is tightly linked to the ligand-binding domain by a disulfide bridge, suggesting a potential role in transmitting a ligand-induced conformational change into the downstream transmembrane region. The structure also reveals the lateral interaction between the two cysteine-rich domains, which could stimulate clustering of the dimeric receptors on the cell surface. We propose a general activation mechanism of the dimeric receptor coupled with both ligand-binding and interprotomer rearrangements.
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Affiliation(s)
- Takanori Muto
- Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
| | - Daisuke Tsuchiya
- Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
| | - Kosuke Morikawa
- Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
- To whom correspondence may be sent at the present address:
Institute for Protein Research, Osaka University, Open Laboratories of Advanced Bioscience and Biotechnology, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan. E-mail:
| | - Hisato Jingami
- Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
- To whom correspondence may be sent at the present address:
Office of Graduate Courses for Integrated Research Training, Kyoto University Faculty of Medicine, Yoshida, Sakyo-Ku, Kyoto 606-8501, Japan. E-mail:
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43
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Enz R. The trick of the tail: protein-protein interactions of metabotropic glutamate receptors. Bioessays 2007; 29:60-73. [PMID: 17187376 DOI: 10.1002/bies.20518] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It was initially believed that G-protein-coupled receptors, such as metabotropic glutamate receptors, could simply be described as individual proteins that are associated with intracellular signal cascades via G-proteins. This view is no longer tenable. Today we know that metabotropic glutamate receptors (mGluRs) can dimerize and bind to a variety of proteins in addition to trimeric G-proteins. These newly identified protein interactions led to the discovery of new regulatory mechanisms that are independent of and sometimes synergistic with the classical G-protein-coupled second messenger pathways. Notably, several of these mechanisms connect mGluR-mediated signaling to other receptor classes, thereby creating a network of different receptor types and associated signal cascades. The intracellular C-termini of mGluRs play a key role in the regulation of these networks, and various new protein interactions of these domains were described recently. Because mGluRs are involved in a variety of physiological and pathophysiological processes, some of the proteins interacting with this receptor class have potential as valuable pharmaceutical targets. This review will give a comprehensive overview of proteins interacting with mGluR C-termini, highlight new evolving regulatory mechanisms for glutamatergic signal transduction and discuss possibilities for future drug development.
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Affiliation(s)
- Ralf Enz
- Emil-Fischer-Zentrum, Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
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Abstract
Calcium sensing receptors (CaR) are unique among G-protein-coupled receptors (GPCRs) since both the first (extracellular) and second (intracellular) messengers are Ca(2+). CaR serves to translate small fluctuations in extracellular Ca(2+) into intracellular Ca(2+) oscillations. In many cells and tissues, CaR also acts as a coincidence detector, sensing both changes in extracellular Ca(2+) plus the presence of various allosteric activators including amino acids, polyamines, and/or peptides. CaR oscillations are uniquely shaped by the activating agonist, that is, Ca(2+) triggers sinusoidal oscillations while Ca(2+) plus phenylalanine trigger transient oscillations of lower frequency. The distinct oscillation patterns generated by Ca(2+)versus Ca(2+) plus phenylalanine are the results of activation of distinct signal transduction pathways. CaR is a member of Family C GPCRs, having a large extracellular agonist binding domain, and functioning as a disulfide-linked dimer. The CaR dimer likely can be driven to distinct active conformations by various Ca(2+) plus modulator combinations, which can drive preferential coupling to divergent signaling pathways. Such plasticity with respect to both agonist and signaling outcomes allows CaR to uniquely contribute to the physiology of organs and tissues where it is expressed. This chapter will examine the structural features of CaR, which contribute to its unique properties, the nature of CaR-induced intracellular Ca(2+) signals and the potential role(s) for CaR in development and differentiation.
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Affiliation(s)
- Gerda E Breitwieser
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania 17822, USA
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45
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Sartorius LJ, Nagappan G, Lipska BK, Lu B, Sei Y, Ren-Patterson R, Li Z, Weinberger DR, Harrison PJ. Alternative splicing of human metabotropic glutamate receptor 3. J Neurochem 2006; 96:1139-48. [PMID: 16417579 DOI: 10.1111/j.1471-4159.2005.03609.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The metabotropic glutamate receptor 3 (GRM3, mGluR3) is important in regulating synaptic glutamate. Here, we report the existence of three splice variants of GRM3 in human brain arising from exon skipping events. The transcripts are expressed in prefrontal cortex, hippocampus and cerebellum, and in B lymphoblasts. We found no evidence for alternative splicing of GRM2. The most abundant GRM3 variant lacks exon 4 (GRM3Delta4). In silico translation analysis of GRM3Delta4 predicts a truncated protein with a conserved extracellular ligand binding domain, absence of a seven-transmembrane domain, and a unique 96-amino acid C-terminus. When expressed in rat hippocampal neurons, GRM3Delta4 is translated into a 60 kDa protein. Immunostaining and cell fractionation data indicate that the truncated protein is primarily membrane-associated. An antibody developed against the GRM3Delta4 C-terminus detects a protein of approximately 60 kDa in human brain lysates and in B lymphoblasts, suggesting translation of GRM3Delta4 in vivo. The existence of the GRM3Delta4 isoform is relevant in the light of the reported association of non-coding single nucleotide polymorphisms (SNPs) in GRM3 with schizophrenia, and with the potential of GRM3 as a therapeutic target for several neuropsychiatric disorders.
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Affiliation(s)
- Leah J Sartorius
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
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46
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Deriu D, Gassmann M, Firbank S, Ristig D, Lampert C, Mosbacher J, Froestl W, Kaupmann K, Bettler B, Grütter M. Determination of the minimal functional ligand-binding domain of the GABAB1b receptor. Biochem J 2005; 386:423-31. [PMID: 15482257 PMCID: PMC1134860 DOI: 10.1042/bj20040804] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the mammalian central nervous system, slow inhibitory neurotransmission is largely mediated by metabotropic GABA(B) receptors (where GABA stands for gamma-aminobutyric acid), which belong to the G-protein-coupled receptor gene family. Functional GABA(B) receptors are assembled from two subunits GABA(B1) (GABA(B) receptor subtype 1) and GABA(B2). For the GABA(B1) subunit, which binds the neurotransmitter GABA, two variants GABA(B1a) (GABA(B) receptor subtype 1 variant a) and GABA(B1b) have been identified. They differ at the very N-terminus of their large glycosylated ECD (extracellular domain). To simplify the structural characterization, we designed truncated GABA(B1) receptors to identify the minimal functional domain which still binds a competitive radioligand and leads to a functional, GABA-responding receptor when co-expressed with GABA(B2). We show that it is necessary to include all the portion of the ECD encoded by exon 6 to exon 14. Furthermore, we studied mutant GABA(B1b) receptors, in which single or all potential N-glycosylation sites are removed. The absence of oligosaccharides does not impair receptor function, suggesting that the unglycosylated ECD of GABA(B1) can be used for further functional or structural investigations.
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Affiliation(s)
- Daniela Deriu
- *Institute of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Martin Gassmann
- †Department of Clinical-Biological Sciences, University of Basel, Pharmazentrum, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
| | - Susan Firbank
- *Institute of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Dorothee Ristig
- ‡Novartis, Institute of Biomedical Research Basel, CH-4002 Basel, Switzerland
| | - Christina Lampert
- ‡Novartis, Institute of Biomedical Research Basel, CH-4002 Basel, Switzerland
| | - Johannes Mosbacher
- ‡Novartis, Institute of Biomedical Research Basel, CH-4002 Basel, Switzerland
| | - Wolfgang Froestl
- ‡Novartis, Institute of Biomedical Research Basel, CH-4002 Basel, Switzerland
| | - Klemens Kaupmann
- ‡Novartis, Institute of Biomedical Research Basel, CH-4002 Basel, Switzerland
| | - Bernhard Bettler
- †Department of Clinical-Biological Sciences, University of Basel, Pharmazentrum, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
| | - Markus G. Grütter
- *Institute of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
- To whom correspondence should be addressed (email )
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47
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Pin JP, Kniazeff J, Liu J, Binet V, Goudet C, Rondard P, Prézeau L. Allosteric functioning of dimeric class C G-protein-coupled receptors. FEBS J 2005; 272:2947-55. [PMID: 15955055 DOI: 10.1111/j.1742-4658.2005.04728.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Whereas most membrane receptors are oligomeric entities, G-protein-coupled receptors have long been thought to function as monomers. Within the last 15 years, accumulating data have indicated that G-protein-coupled receptors can form dimers or even higher ordered oligomers, but the general functional significance of this phenomena is not yet clear. Among the large G-protein-coupled receptor family, class C receptors represent a well-recognized example of constitutive dimers, both subunits being linked, in most cases, by a disulfide bridge. In this review article, we show that class C G-protein-coupled receptors are multidomain proteins and highlight the importance of their dimerization for activation. We illustrate several consequences of this in terms of specific functional properties and drug development.
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Affiliation(s)
- J-P Pin
- Institut de Génomique Fonctionnelle, Montpellier, France.
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48
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Goudet C, Kniazeff J, Hlavackova V, Malhaire F, Maurel D, Acher F, Blahos J, Prézeau L, Pin JP. Asymmetric functioning of dimeric metabotropic glutamate receptors disclosed by positive allosteric modulators. J Biol Chem 2005; 280:24380-5. [PMID: 15863499 PMCID: PMC2557058 DOI: 10.1074/jbc.m502642200] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The recent discovery of positive allosteric modulators (PAMs) for G-protein-coupled receptors open new possibilities to control a number of physiological and pathological processes. Understanding the mechanism of action of such compounds will provide new information on the activation process of these important receptors. Within the last 10 years, a number of studies indicate that G-protein-coupled receptors can form dimers, but the functional significance of this phenomenon remains elusive. Here we used the metabotropic glutamate receptors as a model, because these receptors, for which PAMs have been identified, are constitutive dimers. We used the quality control system of the GABA(B) receptor to generate metabotropic glutamate receptor dimers in which a single subunit binds a PAM. We show that one PAM/dimer is sufficient to enhance receptor activity. Such a potentiation can still be observed if the subunit unable to bind the PAM is also made unable to activate G-proteins. However, the PAM acts as a non-competitive antagonist when it binds in the subunit that cannot activate G-proteins. These data are consistent with a single heptahelical domain reaching the active state per dimer during receptor activation.
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Affiliation(s)
- Cyril Goudet
- IGF, Institut de génomique fonctionnelle
CNRS : UMR5203INSERM : U661Université Montpellier IUniversité Montpellier II - Sciences et Techniques du Languedoc141, Rue de la Cardonille
34094 MONTPELLIER CEDEX 5,FR
| | - Julie Kniazeff
- IGF, Institut de génomique fonctionnelle
CNRS : UMR5203INSERM : U661Université Montpellier IUniversité Montpellier II - Sciences et Techniques du Languedoc141, Rue de la Cardonille
34094 MONTPELLIER CEDEX 5,FR
| | - Veronika Hlavackova
- Department of Molecular Pharmacology
Institute of Experimental MedicineAcademy of Science of Czech RepublicVidenska 1083, 14220 Prague 4,CZ
| | - Fanny Malhaire
- IGF, Institut de génomique fonctionnelle
CNRS : UMR5203INSERM : U661Université Montpellier IUniversité Montpellier II - Sciences et Techniques du Languedoc141, Rue de la Cardonille
34094 MONTPELLIER CEDEX 5,FR
| | - Damien Maurel
- Cis Bio International
Cis Bio InternationalSite de Marcoule
30204 Bagnols sur Ceze Cedex,FR
| | - Francine Acher
- CBPT, Chimie et biochimie pharmacologiques et toxicologiques
CNRS : UMR8601CNRS : IFR95Université Paris Descartes - Paris V45 Rue des Saints-Pères
75270 PARIS CEDEX 06,FR
| | - Jaroslav Blahos
- Department of Molecular Pharmacology
Institute of Experimental MedicineAcademy of Science of Czech RepublicVidenska 1083, 14220 Prague 4,CZ
| | - Laurent Prézeau
- IGF, Institut de génomique fonctionnelle
CNRS : UMR5203INSERM : U661Université Montpellier IUniversité Montpellier II - Sciences et Techniques du Languedoc141, Rue de la Cardonille
34094 MONTPELLIER CEDEX 5,FR
| | - Jean-Philippe Pin
- IGF, Institut de génomique fonctionnelle
CNRS : UMR5203INSERM : U661Université Montpellier IUniversité Montpellier II - Sciences et Techniques du Languedoc141, Rue de la Cardonille
34094 MONTPELLIER CEDEX 5,FR
- * Correspondence should be adressed to: Jean-Philippe Pin
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Kew JNC, Kemp JA. Ionotropic and metabotropic glutamate receptor structure and pharmacology. Psychopharmacology (Berl) 2005; 179:4-29. [PMID: 15731895 DOI: 10.1007/s00213-005-2200-z] [Citation(s) in RCA: 472] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Accepted: 01/26/2005] [Indexed: 12/12/2022]
Abstract
RATIONALE L: -Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS) and mediates its actions via activation of both ionotropic and metabotropic receptor families. The development of selective ligands, including competitive agonists and antagonists and positive and negative allosteric modulators, has enabled investigation of the functional roles of glutamate receptor family members. OBJECTIVE In this review we describe the subunit structure and composition of the ionotropic and metabotropic glutamate receptors and discuss their pharmacology, particularly with respect to selective tools useful for investigation of their function in the CNS. RESULTS A large number of ligands are now available that are selective either for glutamate receptor subfamilies or for particular receptor subtypes. Such ligands have enabled considerable advances in the elucidation of the physiological and pathophysiological roles of receptor family members. Furthermore, efficacy in animal models of neurological and psychiatric disorders has supported the progression of several glutamatergic ligands into clinical studies. These include ionotropic glutamate receptor antagonists, which have entered clinical trials for disorders including epilepsy and ischaemic stroke, alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) receptor positive allosteric modulators which are under evaluation as cognitive enhancers, and metabotropic glutamate receptor 2 (mGluR2) agonists which are undergoing clinical evaluation as anxiolytics. Furthermore, preclinical studies have illustrated therapeutic potential for ligands selective for other receptor subtypes in various disorders. These include mGluR1 antagonists in pain, mGluR5 antagonists in anxiety, pain and drug abuse and mGluR5 positive allosteric modulators in schizophrenia. CONCLUSIONS Selective pharmacological tools have enabled the study of glutamate receptors. However, pharmacological coverage of the family is incomplete and considerable scope remains for the development of novel ligands, particularly those with in vivo utility, and for the their use together with existing tools for the further investigation of the roles of receptor family members in CNS function and as potentially novel therapeutics.
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Affiliation(s)
- James N C Kew
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline, New Frontiers Science Park, Harlow, Essex CM19 5AW, UK.
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50
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Hlavackova V, Goudet C, Kniazeff J, Zikova A, Maurel D, Vol C, Trojanova J, Prézeau L, Pin JP, Blahos J. Evidence for a single heptahelical domain being turned on upon activation of a dimeric GPCR. EMBO J 2005; 24:499-509. [PMID: 15660124 PMCID: PMC548662 DOI: 10.1038/sj.emboj.7600557] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Accepted: 12/23/2004] [Indexed: 11/08/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) have been shown to form dimers, but the relevance of this phenomenon in G-protein activation is not known. Among the large GPCR family, metabotropic glutamate (mGlu) receptors are constitutive dimers. Here we examined whether both heptahelical domains (HDs) are turned on upon full receptor activation. To that aim, we measured G-protein coupling efficacy of dimeric mGlu receptors in which one subunit bears specific mutations. We show that a mutation in the third intracellular loop (i3 loop) known to prevent G-protein activation in a single subunit decreases coupling efficacy. However, when a single HD is blocked in its inactive state using an inverse agonist, 2-methyl-6-(phenylethynyl)pyridine (MPEP), no decrease in receptor activity is observed. Interestingly, in a receptor dimer in which the subunit that binds MPEP is mutated in its i3 loop, MPEP enhances agonist-induced activity, reflecting a 'better' activation of the adjacent HD. These data are consistent with a model in which a single HD is turned on upon activation of such homodimeric receptors and raise important issues in deciphering the functional role of GPCR dimer formation for G-protein activation.
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Affiliation(s)
- Veronika Hlavackova
- Department of Molecular Pharmacology, Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
| | - Cyril Goudet
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
| | - Julie Kniazeff
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
| | - Alice Zikova
- Department of Molecular Pharmacology, Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Damien Maurel
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
- Cis Bio International, Bagnols-sur-Cèze, France
| | - Claire Vol
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
| | - Johana Trojanova
- Department of Molecular Pharmacology, Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Laurent Prézeau
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
| | - Jean-Philippe Pin
- Department of Molecular Pharmacology, Laboratory of Functional Genomic, CNRS unité propre de Recherche 2580, Montpellier, France
- Co-last authors
- UPR-CNRS 9023, Mecanismes Moleculaires des, Communications Cellulaires, CCIPE, Rue de la Cardonille 141, 34094 Montpellier Cedex 5, France. Tel.: +33 467 14 2988; Fax: +33 467 54 2432; E-mail:
| | - Jaroslav Blahos
- Department of Molecular Pharmacology, Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
- Co-last authors
- Department of Molecular Pharmacology, Institute of Experimental Medicine, Czech Academy of Science, Videnska 1083, 142 20 Prague 4, Czech Republic. Tel.: +420 2 96 44 2725; Fax: +420 2 96 44 2109; E-mail:
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