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Ruiz-Viroga V, de Ceglia M, Morelli L, Castaño EM, Calvo EB, Suárez J, Rodríguez de Fonseca F, Galeano P, Lagos P. Acute intrahippocampal administration of melanin-concentrating hormone impairs memory consolidation and decreases the expression of MCHR-1 and TrkB receptors. Prog Neuropsychopharmacol Biol Psychiatry 2023; 123:110703. [PMID: 36565982 DOI: 10.1016/j.pnpbp.2022.110703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Interest in the role of melanin-concentrating hormone (MCH) in memory processes has increased in recent years, with some studies reporting memory-enhancing effects, while others report deleterious effects. Due to these discrepancies, this study seeks to provide new evidence about the role of MCH in memory consolidation and its relation with BDNF/TrkB system. To this end, in the first experiment, increased doses of MCH were acutely administered in both hippocampi to groups of male rats (25, 50, 200, and 500 ng). Microinjections were carried out immediately after finishing the sample trial of two hippocampal-dependent behavioral tasks: the Novel Object Recognition Test (NORT) and the modified Elevated Plus Maze (mEPM) test. Results indicated that a dose of 200 ng of MCH or higher impaired memory consolidation in both tasks. A second experiment was performed in which a dose of 200 ng of MCH was administered alone or co-administered with the MCHR-1 antagonist ATC-0175 at the end of the sample trial in the NORT. Results showed that MCH impaired memory consolidation, while the co-administration with ATC-0175 reverted this detrimental effect. Moreover, MCH induced a significant decrease in hippocampal MCHR-1 and TrkB expression with no modification in the expression of BDNF and NMDA receptor subunits NR1, NR2A, and NR2B. These results suggest that MCH in vivo elicits pro-amnesic effects in the rat hippocampus by decreasing the availability of its receptor and TrkB receptors, thus linking both endogenous systems to memory processes.
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Affiliation(s)
- Vicente Ruiz-Viroga
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Gral. Flores 2125, Montevideo ZP11800, Uruguay
| | - Marialuisa de Ceglia
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Av. Carlos Haya 82, Málaga 29010, Spain.
| | - Laura Morelli
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Eduardo M Castaño
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Eduardo Blanco Calvo
- Instituto de Investigación Biomédica de Málaga (IBIMA), Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Campus de Teatinos S/N, Málaga 29071, Spain.
| | - Juan Suárez
- Instituto de Investigación Biomédica de Málaga (IBIMA), Departamento de Anatomía Humana, Medicina Legal e Historia de la Ciencia, Universidad de Málaga, Málaga 29071, Spain.
| | - Fernando Rodríguez de Fonseca
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Av. Carlos Haya 82, Málaga 29010, Spain.
| | - Pablo Galeano
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Patricia Lagos
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Gral. Flores 2125, Montevideo ZP11800, Uruguay.
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Jakubík J, Randáková A. Insights into the operational model of agonism of receptor dimers. Expert Opin Drug Discov 2022; 17:1181-1191. [PMID: 36369915 DOI: 10.1080/17460441.2023.2147502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 11/10/2022] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Accurate ranking of efficacies and potencies of agonists is essential in the discovery of new selective agonists. For the purpose of system-independent ranking of agonists, the operational model of agonism (OMA) has become a standard. Many receptors function as oligomers which makes functional responses more complex, requiring an extension of the original OMA. AREAS COVERED Explicit equations of the operational model of agonism of receptor dimers (OMARD) were derived. The OMARD can be applied to any receptor possessing two orthosteric sites. The behavior of OMARD was analyzed to demonstrate its complexity and relation to experimental data. Properties of OMARD and OMA equations were compared to demonstrate their pros and cons. EXPERT OPINION Extension of OMA by slope factors gives simple equations of functional response that are easy to fit experimental data but results may be inaccurate because of exponentiation of operational efficacy. Also, such equations cannot accommodate bell-shaped curves. Explicit equations of OMARD give accurate results but are complex and tedious to fit experimental data. All operational models use inter-dependent parameters that are a hurdle in the fitting. A good understanding of OMARD behavior helps to overcome such obstacles.
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Affiliation(s)
- Jan Jakubík
- Laboratory of Neurochemistry, Institute of Physiology CAS, Prague, Czech Republic
| | - Alena Randáková
- Laboratory of Neurochemistry, Institute of Physiology CAS, Prague, Czech Republic
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Liu J, Tang H, Xu C, Zhou S, Zhu X, Li Y, Prézeau L, Xu T, Pin JP, Rondard P, Ji W, Liu J. Biased signaling due to oligomerization of the G protein-coupled platelet-activating factor receptor. Nat Commun 2022; 13:6365. [PMID: 36289206 PMCID: PMC9606269 DOI: 10.1038/s41467-022-34056-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/11/2022] [Indexed: 12/25/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are important drug targets that mediate various signaling pathways by activating G proteins and engaging β-arrestin proteins. Despite its importance for the development of therapeutics with fewer side effects, the underlying mechanism that controls the balance between these signaling modes of GPCRs remains largely unclear. Here, we show that assembly into dimers and oligomers can largely influence the signaling mode of the platelet-activating factor receptor (PAFR). Single-particle analysis results show that PAFR can form oligomers at low densities through two possible dimer interfaces. Stabilization of PAFR oligomers through cross-linking increases G protein activity, and decreases β-arrestin recruitment and agonist-induced internalization significantly. Reciprocally, β-arrestin prevents PAFR oligomerization. Our results highlight a mechanism involved in the control of receptor signaling, and thereby provide important insights into the relationship between GPCR oligomerization and downstream signaling.
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Affiliation(s)
- Junke Liu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China ,grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Hengmin Tang
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Chanjuan Xu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Shengnan Zhou
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Xunying Zhu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China
| | - Yuanyuan Li
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Laurent Prézeau
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Tao Xu
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
| | - Jean-Philippe Pin
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Philippe Rondard
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, Cedex France
| | - Wei Ji
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
| | - Jianfeng Liu
- grid.33199.310000 0004 0368 7223Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei China ,grid.9227.e0000000119573309Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Chinese Academy of Sciences, 510005 Guangzhou, China
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Giampà M, Sgobba E. Insight to Functional Conformation and Noncovalent Interactions of Protein-Protein Assembly Using MALDI Mass Spectrometry. Molecules 2020; 25:E4979. [PMID: 33126406 PMCID: PMC7662314 DOI: 10.3390/molecules25214979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/22/2020] [Accepted: 10/24/2020] [Indexed: 11/16/2022] Open
Abstract
Noncovalent interactions are the keys to the structural organization of biomolecule e.g., proteins, glycans, lipids in the process of molecular recognition processes e.g., enzyme-substrate, antigen-antibody. Protein interactions lead to conformational changes, which dictate the functionality of that protein-protein complex. Besides biophysics techniques, noncovalent interaction and conformational dynamics, can be studied via mass spectrometry (MS), which represents a powerful tool, due to its low sample consumption, high sensitivity, and label-free sample. In this review, the focus will be placed on Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) and its role in the analysis of protein-protein noncovalent assemblies exploring the relationship within noncovalent interaction, conformation, and biological function.
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Affiliation(s)
- Marco Giampà
- MR Cancer Group, Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Olav Kyrres Gate 9, 7030 Trondheim, Norway
| | - Elvira Sgobba
- Genetics and Plant Physiology, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden;
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Zamel IA, Palakkott A, Ashraf A, Iratni R, Ayoub MA. Interplay Between Angiotensin II Type 1 Receptor and Thrombin Receptor Revealed by Bioluminescence Resonance Energy Transfer Assay. Front Pharmacol 2020; 11:1283. [PMID: 32973514 PMCID: PMC7468457 DOI: 10.3389/fphar.2020.01283] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 08/03/2020] [Indexed: 12/22/2022] Open
Abstract
The key hormone of the renin-angiotensin system (RAS), angiotensin II (AngII), and thrombin are known to play major roles in the vascular system and its related disorders. Previous studies reported connections between AngII and thrombin in both physiological and pathophysiological models. However, the molecular mechanisms controlling such interplay at the level of their receptors belonging to the family of G protein-coupled receptors (GPCRs) are not fully understood. In this study, we investigated the functional interaction between the AngII type 1 receptor (AT1R) and the thrombin receptor [or protease-activated receptor 1 (PAR1)] in human embryonic kidney 293 (HEK293) cells. For this, we used various bioluminescence resonance energy transfer (BRET) proximity-based assays to profile the coupling to the heterotrimeric Gαq protein, β-arrestin recruitment, and receptor internalization and trafficking in intact cells. The overall dose-response and real-time kinetic BRET data demonstrated the specific molecular proximity between AT1R and PAR1 resulting in their functional interaction. This was characterized by thrombin inducing BRET increase within AT1R/Gαq and AT1R/β-arrestin pairs and synergistic effects observed upon the concomitant activation of both receptors suggesting a positive allosteric interaction. The BRET data corroborated with the data on the downstream Gαq/inositol phosphate pathway. Moreover, the selective pharmacological blockade of the receptors revealed the implication of both AT1R and PAR1 protomers in such a synergistic interaction and the possible transactivation of AT1R by PAR1. Interestingly, the positive action of PAR1 on AT1R activation was contrasted with its apparent inhibition of AT1R internalization and its endosomal trafficking. Finally, BRET saturation and co-immunoprecipitation assays supported the physical AT1-PAR1 interaction in HEK293 cells. Our study reveals for the first time the functional interaction between AT1R and PAR1 in vitro characterized by a transactivation and positive allosteric modulation of AT1R and inhibition of its desensitization and internalization. This finding may constitute the molecular basis of the well-known interplay between RAS and thrombin. Thus, our data should lead to revising some findings on the implication of RAS and thrombin in vascular physiology and pathophysiology revealing the importance to consider the functional and pharmacological interaction between AT1R and thrombin receptors.
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Affiliation(s)
- Isra Al Zamel
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Abdulrasheed Palakkott
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Arshida Ashraf
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Rabah Iratni
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Mohammed Akli Ayoub
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
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6
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Xue L, Sun Q, Zhao H, Rovira X, Gai S, He Q, Pin JP, Liu J, Rondard P. Rearrangement of the transmembrane domain interfaces associated with the activation of a GPCR hetero-oligomer. Nat Commun 2019; 10:2765. [PMID: 31235691 PMCID: PMC6591306 DOI: 10.1038/s41467-019-10834-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 06/04/2019] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) can integrate extracellular signals via allosteric interactions within dimers and higher-order oligomers. However, the structural bases of these interactions remain unclear. Here, we use the GABAB receptor heterodimer as a model as it forms large complexes in the brain. It is subjected to genetic mutations mainly affecting transmembrane 6 (TM6) and involved in human diseases. By cross-linking, we identify the transmembrane interfaces involved in GABAB1-GABAB2, as well as GABAB1-GABAB1 interactions. Our data are consistent with an oligomer made of a row of GABAB1. We bring evidence that agonist activation induces a concerted rearrangement of the various interfaces. While the GB1-GB2 interface is proposed to involve TM5 in the inactive state, cross-linking of TM6s lead to constitutive activity. These data bring insight for our understanding of the allosteric interaction between GPCRs within oligomers. G protein-coupled receptors (GPCRs), such as GABAB, can integrate extracellular signals via allosteric interactions within dimers and oligomers. Here authors use crosslinking and identify two transmembrane interfaces in GABAB which undergo a concerted rearrangement upon agonist activation.
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Affiliation(s)
- Li Xue
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Qian Sun
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Han Zhao
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France.,Molecular Photopharmacology Research Group, The Tissue Repair and Regeneration Laboratory, University of Vic - Central University of Catalonia, C. de la Laura, 13, Vic, 08500, Spain
| | - Siyu Gai
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Qianwen He
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France.
| | - Jianfeng Liu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France
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7
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Pin JP, Kniazeff J, Prézeau L, Liu JF, Rondard P. GPCR interaction as a possible way for allosteric control between receptors. Mol Cell Endocrinol 2019; 486:89-95. [PMID: 30849406 DOI: 10.1016/j.mce.2019.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/17/2022]
Abstract
For more than twenty years now, GPCR dimers and larger oligomers have been the subject of intense debates. Evidence for a role of such complexes in receptor trafficking to and from the plasma membrane have been provided. However, one main issue is of course to determine whether or not such a phenomenon can be responsible for an allosteric and reciprocal control (allosteric control) of the subunits. Such a possibility would indeed add to the possible ways a cell integrates various signals targeting GPCRs. Among the large GPCR family, the class C receptors that include mGlu and GABAB receptors, represent excellent models to examine such a possibility as they are mandatory dimers. In the present review, we will report on the observed allosteric interaction between the subunits of class C GPCRs, both mGluRs and GABABRs, and on the structural bases of these interactions. We will then discuss these findings for other GPCR types such as the rhodopsin-like class A receptors. We will show that many of the observations made with class C receptors have also been reported with class A receptors, suggesting that the mechanisms involved in the allosteric control between subunits in GPCR dimers may not be unique to class C GPCRs.
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Affiliation(s)
- Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Laurent Prézeau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jiang-Feng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
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8
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Garton M, MacKinnon SS, Malevanets A, Wodak SJ. Interplay of self-association and conformational flexibility in regulating protein function. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0190. [PMID: 29735742 DOI: 10.1098/rstb.2017.0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 12/18/2022] Open
Abstract
Many functional roles have been attributed to homodimers, the most common mode of protein self-association, notably in the regulation of enzymes, ion channels, transporters and transcription factors. Here we review findings that offer new insights into the different roles conformational flexibility plays in regulating homodimer function. Intertwined homodimers of two-domain proteins and their related family members display significant conformational flexibility, which translates into concerted motion between structural domains. This flexibility enables the corresponding proteins to regulate function across family members by modulating the spatial positions of key recognition surfaces of individual domains, to either maintain subunit interfaces, alter them or break them altogether, leading to a variety of functional consequences. Many proteins may exist as monomers but carry out their biological function as homodimers or higher-order oligomers. We present early evidence that in such systems homodimer formation primes the protein for its functional role. It does so by inducing elevated mobility in protein regions corresponding to the binding epitopes of functionally important ligands. In some systems this process acts as an allosteric response elicited by the self-association reaction itself. Our analysis furthermore suggests that the induced extra mobility likely facilitates ligand binding through the mechanism of conformational selection.This article is part of a discussion meeting issue 'Allostery and molecular machines'.
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Affiliation(s)
- Michael Garton
- Department of Molecular Genetics, University of Toronto, The Donnelly Centre, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Stephen S MacKinnon
- Cyclica Inc., 18 King Street East, Suite 810, Toronto, Ontario M5C 1C4, Canada
| | - Anatoly Malevanets
- Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| | - Shoshana J Wodak
- VIB Structural Biology research Centre, VUB, Building E Pleinlaan 2, 1050 Brussels, Belgium
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9
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Ventura-Bixenshpaner H, Asraf H, Chakraborty M, Elkabets M, Sekler I, Taylor KM, Hershfinkel M. Enhanced ZnR/GPR39 Activity in Breast Cancer, an Alternative Trigger of Signaling Leading to Cell Growth. Sci Rep 2018; 8:8119. [PMID: 29802348 PMCID: PMC5970167 DOI: 10.1038/s41598-018-26459-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/20/2018] [Indexed: 12/14/2022] Open
Abstract
Acquired resistance to the estrogen receptor (ER) antagonist tamoxifen, is a major obstacle in treatment of breast cancer. Changes in Zn2+ accumulation and distribution are associated with tamoxifen-resistance and breast cancer progression. The Zn2+-sensing G-protein coupled receptor, ZnR/GPR39, triggers signaling leading to cell growth, but a role for this receptor in breast cancer in unknown. Using fluorescence imaging, we found Zn2+-dependent Ca2+ release, mediated by ZnR/GPR39 activity, in TAMR tamoxifen-resistant cells derived from MCF-7 cells, but not in ER-expressing MCF-7 or T47D cells. Furthermore, ZnR/GPR39 signaling was monitored in ER negative BT20, MDA-MB-453 and JIMT-1 cells. Expression of ZnR/GPR39 was increased in grade 3 human breast cancer biopsies compared to grade 2. Consistently, analysis of two breast cancer patient cohorts, GDS4057 and TCGA, indicated that in ER-negative tumors higher ZnR/GPR39 mRNA levels are associated with more aggressive tumors. Activation of ZnR/GPR39 in TAMR cells triggered MAPK, mTOR and PI3K signaling. Importantly, enhanced cell growth and invasiveness was observed in the ER negative breast cancer cells, TAMR, MDA-MB-453 and BT20 cells but not in the ER expressing MCF-7 cells. Thus, we suggest ZnR/GPR39 as a potential therapeutic target for combination treatment in breast cancer, particularly relevant in ER negative tumors.
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Affiliation(s)
- Hila Ventura-Bixenshpaner
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Moumita Chakraborty
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Moshe Elkabets
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Kathryn M Taylor
- Breast Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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10
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Hasdemir B, Mahajan S, Oses-Prieto J, Chand S, Woolley M, Burlingame A, Grammatopoulos DK, Bhargava A. Actin cytoskeleton-dependent regulation of corticotropin-releasing factor receptor heteromers. Mol Biol Cell 2017; 28:2386-2399. [PMID: 28701349 PMCID: PMC5576902 DOI: 10.1091/mbc.e16-11-0778] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 06/30/2017] [Accepted: 07/07/2017] [Indexed: 01/02/2023] Open
Abstract
A physical interaction is shown between CRF1R and CRF2R, two class B G protein–coupled receptors that mediate stress and immune responses. Trafficking of CRF2R but not CRF1R is actin dependent, and coexpression of the two receptors alters actin-independent trafficking. Receptor cross-talk alters agonist binding and signaling. Stress responses are highly nuanced and variable, but how this diversity is achieved by modulating receptor function is largely unknown. Corticotropin-releasing factor receptors (CRFRs), class B G protein–coupled receptors, are pivotal in mediating stress responses. Here we show that the two known CRFRs interact to form heteromeric complexes in HEK293 cells coexpressing both CRFRs and in vivo in mouse pancreas. Coimmunoprecipitation and mass spectrometry confirmed the presence of both CRF1R and CRF2βR, along with actin in these heteromeric complexes. Inhibition of actin filament polymerization prevented the transport of CRF2βR to the cell surface but had no effect on CRF1R. Transport of CRF1R when coexpressed with CRF2βR became actin dependent. Simultaneous stimulation of cells coexpressing CRF1R+CRF2βR with their respective high-affinity agonists, CRF+urocortin2, resulted in approximately twofold increases in peak Ca2+ responses, whereas stimulation with urocortin1 that binds both receptors with 10-fold higher affinity did not. The ability of CRFRs to form heteromeric complexes in association with regulatory proteins is one mechanism to achieve diverse and nuanced function.
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Affiliation(s)
- Burcu Hasdemir
- Osher Center for Integrative Medicine, University of California, San Francisco, San Francisco, CA 94143.,Department of Obstetrics & Gynecology, University of California, San Francisco, San Francisco, CA 94143
| | - Shilpi Mahajan
- Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Juan Oses-Prieto
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Shreya Chand
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Michael Woolley
- Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Alma Burlingame
- Departments of Pediatrics, Pharmacology, and Chemistry, University of California, San Francisco, San Francisco, CA 94143
| | - Dimitris K Grammatopoulos
- Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Aditi Bhargava
- Osher Center for Integrative Medicine, University of California, San Francisco, San Francisco, CA 94143 .,Department of Surgery, University of California, San Francisco, San Francisco, CA 94143.,Department of Obstetrics & Gynecology, University of California, San Francisco, San Francisco, CA 94143
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11
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Charmandari E, Guan R, Zhang M, Silveira LG, Fan QR, Chrousos GP, Sertedaki AC, Latronico AC, Segaloff DL. Misfolding Ectodomain Mutations of the Lutropin Receptor Increase Efficacy of Hormone Stimulation. Mol Endocrinol 2015; 30:62-76. [PMID: 26554443 DOI: 10.1210/me.2015-1205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We demonstrate 2 novel mutations of the LHCGR, each homozygous, in a 46,XY patient with severe Leydig cell hypoplasia. One is a mutation in the signal peptide (p.Gln18_Leu19ins9; referred to here as SP) that results in an alteration of the coding sequence of the N terminus of the mature mutant receptor. The other mutation (p.G71R) is also within the ectodomain. Similar to many other inactivating mutations, the cell surface expression of recombinant human LHR(SP,G71R) is greatly reduced due to intracellular retention. However, we made the unusual discovery that the intrinsic efficacy for agonist-stimulated cAMP in the reduced numbers of receptors on the cell surface was greatly increased relative to the same low number of cell surface wild-type receptor. Remarkably, this appears to be a general attribute of misfolding mutations in the ectodomains, but not serpentine domains, of the gonadotropin receptors. These findings suggest that there must be a common, shared mechanism by which disparate mutations in the ectodomain that cause misfolding and therefore reduced cell surface expression concomitantly confer increased agonist efficacy to those receptor mutants on the cell surface. Our data further suggest that, due to their increased agonist efficacy, extremely small changes in cell surface expression of misfolded ectodomain mutants cause larger than expected alterations in the cellular response to agonist. Therefore, for inactivating LHCGR mutations causing ectodomain misfolding, the numbers of cell surface mutant receptors on fetal Leydig cells of 46,XY individuals exert a more exquisite effect on the relative severity of the clinical phenotypes than already appreciated.
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Affiliation(s)
- E Charmandari
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - R Guan
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - M Zhang
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - L G Silveira
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Q R Fan
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - G P Chrousos
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - A C Sertedaki
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - A C Latronico
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - D L Segaloff
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
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12
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Bellot M, Galandrin S, Boularan C, Matthies HJ, Despas F, Denis C, Javitch J, Mazères S, Sanni SJ, Pons V, Seguelas MH, Hansen JL, Pathak A, Galli A, Sénard JM, Galés C. Dual agonist occupancy of AT1-R-α2C-AR heterodimers results in atypical Gs-PKA signaling. Nat Chem Biol 2015; 11:271-9. [PMID: 25706338 DOI: 10.1038/nchembio.1766] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/09/2015] [Indexed: 12/25/2022]
Abstract
Hypersecretion of norepinephrine (NE) and angiotensin II (AngII) is a hallmark of major prevalent cardiovascular diseases that contribute to cardiac pathophysiology and morbidity. Herein, we explore whether heterodimerization of presynaptic AngII AT1 receptor (AT1-R) and NE α2C-adrenergic receptor (α2C-AR) could underlie their functional cross-talk to control NE secretion. Multiple bioluminescence resonance energy transfer and protein complementation assays allowed us to accurately probe the structures and functions of the α2C-AR-AT1-R dimer promoted by ligand binding to individual protomers. We found that dual agonist occupancy resulted in a conformation of the heterodimer different from that induced by active individual protomers and triggered atypical Gs-cAMP-PKA signaling. This specific pharmacological signaling unit was identified in vivo to promote not only NE hypersecretion in sympathetic neurons but also sympathetic hyperactivity in mice. Thus, we uncovered a new process by which GPCR heterodimerization creates an original functional pharmacological entity and that could constitute a promising new target in cardiovascular therapeutics.
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Affiliation(s)
- Morgane Bellot
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Ségolène Galandrin
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Cédric Boularan
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Heinrich J Matthies
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Fabien Despas
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Colette Denis
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jonathan Javitch
- 1] Center for Molecular Recognition and Departments of Psychiatry and Pharmacology, Columbia University, New York, New York, USA. [2] College of Physicians and Surgeons, Columbia University, New York, New York, USA. [3] Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Serge Mazères
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, UMR 508, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Samra Joke Sanni
- 1] Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark. [2] Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Véronique Pons
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Marie-Hélène Seguelas
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jakob L Hansen
- Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Atul Pathak
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Aurelio Galli
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [3] Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [4] Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jean-Michel Sénard
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
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13
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Xue L, Rovira X, Scholler P, Zhao H, Liu J, Pin JP, Rondard P. Major ligand-induced rearrangement of the heptahelical domain interface in a GPCR dimer. Nat Chem Biol 2015; 11:134-40. [PMID: 25503927 DOI: 10.1038/nchembio.1711] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/14/2014] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are major players in cell communication. Although they form functional monomers, increasing evidence indicates that GPCR dimerization has a critical role in cooperative phenomena that are important for cell signal integration. However, the structural bases of these phenomena remain elusive. Here, using well-characterized receptor dimers, the metabotropic glutamate receptors (mGluRs), we show that structural changes at the dimer interface are linked to receptor activation. We demonstrate that the main dimer interface is formed by transmembrane α helix 4 (TM4) and TM5 in the inactive state and by TM6 in the active state. This major change in the dimer interface is required for receptor activity because locking the TM4-TM5 interface prevents activation by agonist, whereas locking the TM6 interface leads to a constitutively active receptor. These data provide important information on the activation mechanism of mGluRs and improve our understanding of the structural basis of the negative cooperativity observed in these GPCR dimers.
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MESH Headings
- Alanine/genetics
- Animals
- COS Cells
- Chlorocebus aethiops
- Cysteine/genetics
- HEK293 Cells
- Humans
- Ligands
- Models, Molecular
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Multimerization
- Protein Structure, Tertiary
- Protein Subunits
- Rats
- Receptor, Metabotropic Glutamate 5/agonists
- Receptor, Metabotropic Glutamate 5/chemistry
- Receptor, Metabotropic Glutamate 5/genetics
- Receptors, GABA-B/chemistry
- Receptors, GABA-B/genetics
- Receptors, GABA-B/metabolism
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Transcriptional Activation
- Transfection
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Affiliation(s)
- Li Xue
- 1] Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. [2] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [3] INSERM, U661, Montpellier, France. [4] Université Montpellier 1 &2, Montpellier, France
| | - Xavier Rovira
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Pauline Scholler
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Han Zhao
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Philippe Rondard
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
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14
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Tovo-Rodrigues L, Roux A, Hutz MH, Rohde LA, Woods AS. Functional characterization of G-protein-coupled receptors: a bioinformatics approach. Neuroscience 2014; 277:764-79. [PMID: 24997265 DOI: 10.1016/j.neuroscience.2014.06.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/22/2014] [Accepted: 06/18/2014] [Indexed: 12/18/2022]
Abstract
Complex molecular and cellular mechanisms regulate G protein-coupled receptors (GPCRs). It is suggested that proteins intrinsically disordered regions (IDRs) are to play a role in GPCR's intra and extracellular regions plasticity, due to their potential for post-translational modification and interaction with other proteins. These regions are defined as lacking a stable three-dimensional (3D) structure. They are rich in hydrophilic and charged, amino acids and are capable to assume different conformations which allow them to interact with multiple partners. In this study we analyzed 75 GPCR involved in synaptic transmission using computational tools for sequence-based prediction of IDRs within a protein. We also evaluated putative ligand-binding motifs using receptor sequences. The disorder analysis indicated that neurotransmitter GPCRs have a significant amount of disorder in their N-terminus, third intracellular loop (3IL) and C-terminus. About 31%, 39% and 53% of human GPCR involved in synaptic transmission are disordered in these regions. Thirty-three percent of receptors show at least one predicted PEST motif, this being statistically greater than the estimate for the rest of human GPCRs. About 90% of the receptors had at least one putative site for dimerization in their 3IL or C-terminus. ELM instances sampled in these domains were 14-3-3, SH3, SH2 and PDZ motifs. In conclusion, the increased flexibility observed in GPCRs, added to the enrichment of linear motifs, PEST and heteromerization sites, may be critical for the nervous system's functional plasticity.
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Affiliation(s)
- L Tovo-Rodrigues
- Department of Genetics, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil; Structural Biology Unit, Integrative Neuroscience Branch, NIDA IRP, NIH, MD, United States
| | - A Roux
- Structural Biology Unit, Integrative Neuroscience Branch, NIDA IRP, NIH, MD, United States
| | - M H Hutz
- Department of Genetics, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - L A Rohde
- Child and Adolescent Psychiatric Division, Department of Psychiatry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - A S Woods
- Structural Biology Unit, Integrative Neuroscience Branch, NIDA IRP, NIH, MD, United States.
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15
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Cortés A, Gracia E, Moreno E, Mallol J, Lluís C, Canela EI, Casadó V. Moonlighting Adenosine Deaminase: A Target Protein for Drug Development. Med Res Rev 2014; 35:85-125. [DOI: 10.1002/med.21324] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Eduard Gracia
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Estefania Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Carme Lluís
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Enric I. Canela
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
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16
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Modeling the allosteric modulation of CCR5 function by Maraviroc. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e297-305. [PMID: 24050281 DOI: 10.1016/j.ddtec.2012.07.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Maraviroc is a non-peptidic, low molecular weight CC chemokine receptor 5 (CCR5) ligand that has recently been marketed for the treatment of HIV infected individuals. This review discusses recent molecular modeling studies of CCR5 by homology to CXC chemokine receptor 4, their contribution to the understanding of the allosteric mode of action of the inhibitor and their potential for the development of future drugs with improved efficiency and preservation of CCR5 biological functions.
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Feng X, Zhang M, Guan R, Segaloff DL. Heterodimerization between the lutropin and follitropin receptors is associated with an attenuation of hormone-dependent signaling. Endocrinology 2013; 154:3925-30. [PMID: 23825122 PMCID: PMC3776865 DOI: 10.1210/en.2013-1407] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The LH receptor (LHR) and FSH receptor (FSHR) are each G protein-coupled receptors that play critical roles in reproductive endocrinology. Each of these receptors has previously been shown to self-associate into homodimers and oligomers shortly after their biosynthesis. As shown herein using bioluminescence resonance energy transfer to detect protein-protein interactions, our data show that the LHR and FSHR, when coexpressed in the same cells, specifically heterodimerize with each other. Further experiments confirm that at least a portion of the cellular LHR/FSHR heterodimers are present on the cell surface and are functional. We then sought to ascertain what effects, if any, heterodimerization between the LHR and FSHR might have on signaling. It was observed that when the LHR was expressed under conditions promoting the heterodimerization with FSHR, LH or human chorionic gonadotropin (hCG) stimulation of Gs was attenuated. Conversely, when the FSHR was expressed under conditions promoting heterodimerization with the LHR, FSH-stimulated Gs activation was attenuated. These results demonstrate that the coexpression of the LHR and FSHR enables heterodimerizaton between the 2 gonadotropin receptors and results in an attenuation of signaling through each receptor.
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Affiliation(s)
- Xiuyan Feng
- PhD, Department of Molecular Physiology and Biophysics, 5-470 Bowen Science Building, The University of Iowa, Iowa City, Iowa 52242.
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Banghart MR, Williams JT, Shah RC, Lavis LD, Sabatini BL. Caged naloxone reveals opioid signaling deactivation kinetics. Mol Pharmacol 2013; 84:687-95. [PMID: 23960100 DOI: 10.1124/mol.113.088096] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The spatiotemporal dynamics of opioid signaling in the brain remain poorly defined. Photoactivatable opioid ligands provide a means to quantitatively measure these dynamics and their underlying mechanisms in brain tissue. Although activation kinetics can be assessed using caged agonists, deactivation kinetics are obscured by slow clearance of agonist in tissue. To reveal deactivation kinetics of opioid signaling we developed a caged competitive antagonist that can be quickly photoreleased in sufficient concentrations to render agonist dissociation effectively irreversible. Carboxynitroveratryl-naloxone (CNV-NLX), a caged analog of the competitive opioid antagonist NLX, was readily synthesized from commercially available NLX in good yield and found to be devoid of antagonist activity at heterologously expressed opioid receptors. Photolysis in slices of rat locus coeruleus produced a rapid inhibition of the ionic currents evoked by multiple agonists of the μ-opioid receptor (MOR), but not of α-adrenergic receptors, which activate the same pool of ion channels. Using the high-affinity peptide agonist dermorphin, we established conditions under which light-driven deactivation rates are independent of agonist concentration and thus intrinsic to the agonist-receptor complex. Under these conditions, some MOR agonists yielded deactivation rates that are limited by G protein signaling, whereas others appeared limited by agonist dissociation. Therefore, the choice of agonist determines which feature of receptor signaling is unmasked by CNV-NLX photolysis.
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Affiliation(s)
- Matthew R Banghart
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston, Massachusetts (M.R.B., R.C.S., B.L.S.); Vollum Institute, Oregon Health & Science University, Portland, Oregon (J.T.W.); and Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia (L.D.L.)
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Quaternary Structure Predictions and Structural Communication Features of GPCR Dimers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:105-42. [DOI: 10.1016/b978-0-12-386931-9.00005-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Bushlin I, Gupta A, Stockton SD, Miller LK, Devi LA. Dimerization with cannabinoid receptors allosterically modulates delta opioid receptor activity during neuropathic pain. PLoS One 2012; 7:e49789. [PMID: 23272051 PMCID: PMC3522681 DOI: 10.1371/journal.pone.0049789] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 10/11/2012] [Indexed: 11/20/2022] Open
Abstract
The diversity of receptor signaling is increased by receptor heteromerization leading to dynamic regulation of receptor function. While a number of studies have demonstrated that family A G-protein-coupled receptors are capable of forming heteromers in vitro, the role of these heteromers in normal physiology and disease has been poorly explored. In this study, direct interactions between CB(1) cannabinoid and delta opioid receptors in the brain were examined. Additionally, regulation of heteromer levels and signaling in a rodent model of neuropathic pain was explored. First we examined changes in the expression, function and interaction of these receptors in the cerebral cortex of rats with a peripheral nerve lesion that resulted in neuropathic pain. We found that, following the peripheral nerve lesion, the expression of both cannabinoid type 1 receptor (CB(1)R) and the delta opioid receptor (DOR) are increased in select brain regions. Concomitantly, an increase in CB(1)R activity and decrease in DOR activity was observed. We hypothesize that this decrease in DOR activity could be due to heteromeric interactions between these two receptors. Using a CB(1)R-DOR heteromer-specific antibody, we found increased levels of CB(1)R-DOR heteromer protein in the cortex of neuropathic animals. We subsequently examined the functionality of these heteromers by testing whether low, non-signaling doses of CB(1)R ligands influenced DOR signaling in the cortex. We found that, in cortical membranes from animals that experienced neuropathic pain, non-signaling doses of CB(1)R ligands significantly enhanced DOR activity. Moreover, this activity is selectively blocked by a heteromer-specific antibody. Together, these results demonstrate an important role for CB(1)R-DOR heteromers in altered cortical function of DOR during neuropathic pain. Moreover, they suggest the possibility that a novel heteromer-directed therapeutic strategy for enhancing DOR activity, could potentially be employed to reduce anxiety associated with chronic pain.
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Affiliation(s)
- Ittai Bushlin
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Steven D. Stockton
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Lydia K. Miller
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Lakshmi A. Devi
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
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Allosteric modulators of rhodopsin-like G protein-coupled receptors: opportunities in drug development. Pharmacol Ther 2012; 135:292-315. [PMID: 22728155 DOI: 10.1016/j.pharmthera.2012.06.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 11/21/2022]
Abstract
Rhodopsin-like (class A) G protein-coupled receptors (GPCRs) are one of the most important classes of drug targets. The discovery that these GPCRs can be allosterically modulated by small drug molecules has opened up new opportunities in drug development. It will allow the drugability of "difficult targets", such as GPCRs activated by large (glyco)proteins, or by very polar or highly lipophilic physiological agonists. Receptor subtype selectivity should be more easily achievable with allosteric than with orthosteric ligands. Allosteric modulation will allow a broad spectrum of pharmacological effects largely expanding that of orthosteric ligands. Furthermore, allosteric modulators may show an improved safety profile as compared to orthosteric ligands. Only recently, the explicit search for allosteric modulators has been started for only a few rhodopsin-like GPCRs. The first negative allosteric modulators (allosteric antagonists) of chemokine receptors, maraviroc (CCR5 receptor), used in HIV therapy, and plerixafor (CXCR4 receptor) for stem cell mobilization, have been approved as drugs. The development of allosteric modulators for rhodopsin-like GPCRs as novel drugs is still at an early stage; it appears highly promising.
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22
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Vauquelin G, Van Liefde I. Radioligand dissociation measurements: potential interference of rebinding and allosteric mechanisms and physiological relevance of the biological model systems. Expert Opin Drug Discov 2012; 7:583-95. [DOI: 10.1517/17460441.2012.687720] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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23
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Jaron-Mendelson M, Yossef R, Appel MY, Zilka A, Hadad U, Afergan F, Rosental B, Engel S, Nedvetzki S, Braiman A, Porgador A. Dimerization of NKp46 Receptor Is Essential for NKp46-Mediated Lysis: Characterization of the Dimerization Site by Epitope Mapping. THE JOURNAL OF IMMUNOLOGY 2012; 188:6165-74. [DOI: 10.4049/jimmunol.1102496] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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24
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Szalai B, Barkai L, Turu G, Szidonya L, Várnai P, Hunyady L. Allosteric interactions within the AT₁ angiotensin receptor homodimer: role of the conserved DRY motif. Biochem Pharmacol 2012; 84:477-85. [PMID: 22579851 DOI: 10.1016/j.bcp.2012.04.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/15/2012] [Accepted: 04/18/2012] [Indexed: 12/20/2022]
Abstract
G protein coupled receptor (GPCR) dimerization has a remarkable impact on the diversity of receptor signaling. Allosteric communication between the protomers of the dimer can alter ligand binding, receptor conformation and interactions with different effector proteins. In this study we investigated the allosteric interactions between wild type and mutant protomers of type 1 angiotensin receptor (AT₁R) dimers transiently expressed in CHO cells. In our experimental setup, one protomer of the dimer was selectively stimulated and the β-arrestin2 binding and conformation alteration of the other protomer was followed. The interaction between β-arrestin2 and the non-stimulated protomer was monitored through a bioluminescence resonance energy transfer (BRET) based method. To measure the conformational alterations in the non-stimulated protomer directly, we also used a BRET based intramolecular receptor biosensor, which was created by inserting yellow fluorescent protein (YFP) into the 3rd intracellular loop of AT₁R and fusing Renilla luciferase (RLuc) to its C terminal region. We have detected β-arrestin2 binding, and altered conformation of the non-stimulated protomer. The cooperative ligand binding of the receptor homodimer was also observed by radioligand dissociation experiments. Mutation of the conserved DRY sequence in the activated protomer, which is also required for G protein activation, abolished all the observed allosteric effects. These data suggest that allosteric interactions in the homodimers of AT₁R significantly affect the function of the non-stimulated protomer, and the conserved DRY motif has a crucial role in these interactions.
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Affiliation(s)
- Bence Szalai
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
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25
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Murat B, Devost D, Andrés M, Mion J, Boulay V, Corbani M, Zingg HH, Guillon G. V1b and CRHR1 receptor heterodimerization mediates synergistic biological actions of vasopressin and CRH. Mol Endocrinol 2012; 26:502-20. [PMID: 22301784 DOI: 10.1210/me.2011-1202] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Vasopressin (AVP) and CRH synergistically regulate adrenocorticotropin and insulin release at the level of the pituitary and pancreas, respectively. Here, we first extended these AVP and CRH coregulation processes to the adrenal medulla. We demonstrate that costimulation of chromaffin cells by AVP and CRH simultaneously induces a catecholamine secretion exceeding the one induced by each hormone alone, thus demonstrating a net potentiation. To further elucidate the molecular mechanisms underlying this synergism, we coexpressed human V1b and CRH receptor (CRHR)1 receptor in HEK293 cells. In this heterologous system, AVP also potentiated CRH-stimulated cAMP accumulation in a dose-dependent and saturable manner. This effect was only partially mimicked by phorbol ester or inhibited by a phospholipase C inhibitor respectively. This finding suggests the existence of an new molecular mechanism, independent from second messenger cross talk. Similarly, CRH potentiated the AVP-induced inositol phosphates production. Using bioluminescence resonance energy transfer, coimmunoprecipitation, and receptor rescue experiments, we demonstrate that V1b and CRHR1 receptors assemble as heterodimers. Moreover, new pharmacological properties emerged upon receptors cotransfection. Taken together, these data strongly suggest that direct molecular interactions between V1b and CRHR1 receptors play an important role in mediating the synergistic interactions between these two receptors.
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Affiliation(s)
- Brigitte Murat
- Institut de Génomique Fonctionnelle, 141 Rue de la Cardonille, Montpellier Cedex 05, France
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26
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Hazell GG, Hindmarch CC, Pope GR, Roper JA, Lightman SL, Murphy D, O’Carroll AM, Lolait SJ. G protein-coupled receptors in the hypothalamic paraventricular and supraoptic nuclei--serpentine gateways to neuroendocrine homeostasis. Front Neuroendocrinol 2012; 33:45-66. [PMID: 21802439 PMCID: PMC3336209 DOI: 10.1016/j.yfrne.2011.07.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/24/2011] [Accepted: 07/06/2011] [Indexed: 12/31/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in the mammalian genome. They are activated by a multitude of different ligands that elicit rapid intracellular responses to regulate cell function. Unsurprisingly, a large proportion of therapeutic agents target these receptors. The paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus are important mediators in homeostatic control. Many modulators of PVN/SON activity, including neurotransmitters and hormones act via GPCRs--in fact over 100 non-chemosensory GPCRs have been detected in either the PVN or SON. This review provides a comprehensive summary of the expression of GPCRs within the PVN/SON, including data from recent transcriptomic studies that potentially expand the repertoire of GPCRs that may have functional roles in these hypothalamic nuclei. We also present some aspects of the regulation and known roles of GPCRs in PVN/SON, which are likely complemented by the activity of 'orphan' GPCRs.
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Affiliation(s)
| | | | | | | | | | | | | | - Stephen J. Lolait
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Dorothy Hodgkin Building, School of Clinical Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
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27
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Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
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28
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Teitler M, Klein MT. A new approach for studying GPCR dimers: drug-induced inactivation and reactivation to reveal GPCR dimer function in vitro, in primary culture, and in vivo. Pharmacol Ther 2011; 133:205-17. [PMID: 22119169 DOI: 10.1016/j.pharmthera.2011.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 10/29/2011] [Indexed: 12/28/2022]
Abstract
GPCRs are a major family of homologous proteins and are key mediators of the effects of numerous endogenous neurotransmitters, hormones, cytokines, therapeutic drugs, and drugs-of-abuse. Despite the enormous amount of research on the pharmacological and biochemical properties of GPCRs, the question as to whether they exist as monomers, dimers, or higher order structures in the body is unanswered. The GPCR dimer field has been dominated by techniques involving recombinant cell lines expressing mutant receptors, often involving the solubilization of the receptors. These techniques cannot be applied in vivo or even to primary cell cultures. This review will focus on a novel approach to exploring the functional properties of homodimers. Studies of the 5-HT(7) and 5-HT(2A) serotonin receptors have revealed that binding of a pseudo-irreversible antagonist ("inactivator") to one of the orthosteric sites of a homodimer abolishes all receptor activity, and subsequent binding of a competitive antagonist to the orthosteric site of the second protomer releases the inactivator, allowing the receptor to return to an active state. This approach demonstrates allosteric crosstalk between protomers of native GPCR homodimers, indicating that GPCRs do exist and function as homodimers in both recombinant cells and rat primary astrocytes. This technique can be applied universally using intact recombinant or primary cells in culture, membrane homogenate preparations and, potentially, in vivo. The data obtained using the 5-HT(7) and 5-HT(2A) receptors are strongly supportive of a GPCR homodimer structure, with little evidence of monomer involvement in the function of these receptors.
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Affiliation(s)
- Milt Teitler
- Center for Neuropharmacology & Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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29
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Vischer HF, Watts AO, Nijmeijer S, Leurs R. G protein-coupled receptors: walking hand-in-hand, talking hand-in-hand? Br J Pharmacol 2011; 163:246-60. [PMID: 21244374 DOI: 10.1111/j.1476-5381.2011.01229.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Most cells express a panel of different G protein-coupled receptors (GPCRs) allowing them to respond to at least a corresponding variety of extracellular ligands. In order to come to an integrative well-balanced functional response these ligand-receptor pairs can often cross-regulate each other. Although most GPCRs are fully capable to induce intracellular signalling upon agonist binding on their own, many GPCRs, if not all, appear to exist and function in homomeric and/or heteromeric assemblies for at least some time. Such heteromeric organization offers unique allosteric control of receptor pharmacology and function between the protomers and might even unmask 'new' features. However, it is important to realize that some functional consequences that are proposed to originate from heteromeric receptor interactions may also be observed due to intracellular crosstalk between signalling pathways of non-associated GPCRs.
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Affiliation(s)
- Henry F Vischer
- Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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30
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Ward RJ, Pediani JD, Milligan G. Heteromultimerization of cannabinoid CB(1) receptor and orexin OX(1) receptor generates a unique complex in which both protomers are regulated by orexin A. J Biol Chem 2011; 286:37414-28. [PMID: 21908614 PMCID: PMC3199489 DOI: 10.1074/jbc.m111.287649] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/09/2011] [Indexed: 11/06/2022] Open
Abstract
Agonist-induced internalization was observed for both inducible and constitutively expressed forms of the cannabinoid CB(1) receptor. These were also internalized by the peptide orexin A, which has no direct affinity for the cannabinoid CB(1) receptor, but only when the orexin OX(1) receptor was co-expressed along with the cannabinoid CB(1) receptor. This effect of orexin A was concentration-dependent and blocked by OX(1) receptor antagonists. Moreover, the ability of orexin A to internalize the CB(1) receptor was also blocked by CB(1) receptor antagonists. Remarkably, orexin A was substantially more potent in producing internalization of the CB(1) receptor than in causing internalization of the bulk OX(1) receptor population, and this was true in cells in which the CB(1) receptor was maintained at a constant level, whereas levels of OX(1) could be varied and vice versa. Both co-immunoprecipitation and cell surface, homogenous time-resolved fluorescence resonance energy transfer based on covalent labeling of N-terminal "SNAP" and "CLIP" tags present in the extracellular N-terminal domain of the receptors confirmed the capacity of these two receptors to heteromultimerize. These studies confirm the capacity of the CB(1) and OX(1) receptors to interact directly and demonstrate that this complex has unique regulatory characteristics. The higher potency of the agonist orexin A to regulate the CB(1)-OX(1) heteromer compared with the OX(1)-OX(1) homomer present in the same cells and the effects of CB(1) receptor antagonists on the function of orexin A suggest an interplay between these two systems that may modulate appetite, feeding, and wakefulness.
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Affiliation(s)
- Richard J. Ward
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - John D. Pediani
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Graeme Milligan
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
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31
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Allostery in GPCRs: 'MWC' revisited. Trends Biochem Sci 2011; 36:663-72. [PMID: 21920759 DOI: 10.1016/j.tibs.2011.08.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 08/16/2011] [Accepted: 08/16/2011] [Indexed: 01/12/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of receptors in the genome and are the targets for at least 30% of current medicines. In recent years, there has been a dramatic increase in the discovery of allosteric modulators of GPCR activity and a growing appreciation of the diverse modes by which GPCRs can be regulated by both orthosteric and allosteric ligands. Interestingly, some of the contemporary views of GPCR function reflect characteristics that are shared by prototypical allosteric proteins, as encompassed in the classic Monod-Wyman-Changeux (MWC) model initially proposed for enzymes and subsequently extended to other protein families. In this review, we revisit the MWC model in the context of emerging structural, functional and operational data on GPCR allostery.
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CODA-RET reveals functional selectivity as a result of GPCR heteromerization. Nat Chem Biol 2011; 7:624-30. [PMID: 21785426 PMCID: PMC3158273 DOI: 10.1038/nchembio.623] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 05/16/2011] [Indexed: 01/09/2023]
Abstract
Here we present a novel method that combines protein complementation with resonance energy transfer to study conformational changes in response to activation of a defined G protein-coupled receptor heteromer, and we apply the approach to the putative dopamine D1-D2 receptor heteromer. Remarkably, the potency of the D2 receptor (D2R) agonist R(–)-Propylnorapomorphine (NPA) to change the Gαi conformation via the D2R protomer in the D1-D2 heteromer was enhanced 10-fold relative to that observed in the D2R homomer. In contrast, the potencies of the D2R agonists dopamine and quinpirole were the same in the homomer and heteromer. Thus, we have uncovered a molecular mechanism for functional selectivity, in which a drug acts differently at a GPCR protomer depending on the identity of the second protomer that participates in forming the signaling unit, opening the door to enhanced pharmacological specificity through targeting differences between homomeric and heteromeric signaling.
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33
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May LT, Bridge LJ, Stoddart LA, Briddon SJ, Hill SJ. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics. FASEB J 2011; 25:3465-76. [PMID: 21715680 PMCID: PMC3177574 DOI: 10.1096/fj.11-186296] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A growing awareness indicates that many G-protein-coupled receptors (GPCRs) exist as homodimers, but the extent of the cooperativity across the dimer interface has been largely unexplored. Here, measurement of the dissociation kinetics of a fluorescent agonist (ABA-X-BY630) from the human A1 or A3 adenosine receptors expressed in CHO-K1 cells has provided evidence for highly cooperative interactions between protomers of the A3-receptor dimer in single living cells. In the absence of competitive ligands, the dissociation rate constants of ABA-X-BY630 from A1 and A3 receptors were 1.45 ± 0.05 and 0.57 ± 0.07 min−1, respectively. At the A3 receptor, this could be markedly increased by both orthosteric agonists and antagonists [15-, 9-, and 19-fold for xanthine amine congener (XAC), 5′-(N-ethyl carboxamido)adenosine (NECA), and adenosine, respectively] and reduced by coexpression of a nonbinding (N250A) A3-receptor mutant. The changes in ABA-X-BY630 dissociation were much lower at the A1 receptor (1.5-, 1.4-, and 1.5-fold). Analysis of the pEC50 values of XAC, NECA, and adenosine for the ABA-X-BY630-occupied A3-receptor dimer yielded values of 6.0 ± 0.1, 5.9 ± 0.1, and 5.2 ± 0.1, respectively. This study provides new insight into the spatial and temporal specificity of drug action that can be provided by allosteric modulation across a GPCR homodimeric interface.—May, L. T., Bridge, L. J., Stoddart, L. A., Briddon, S. J., Hill, S. J. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics.
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Affiliation(s)
- Lauren T May
- Institute of Cell Signalling, School of Biomedical Sciences, The University of Nottingham, Nottingham, UK, NG7 2UH
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34
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Allen MD, Neumann S, Gershengorn MC. Occupancy of both sites on the thyrotropin (TSH) receptor dimer is necessary for phosphoinositide signaling. FASEB J 2011; 25:3687-94. [PMID: 21705666 DOI: 10.1096/fj.11-188961] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The thyroid-stimulating hormone (TSH) receptor signals via G(s) to produce cAMP and via G(q/11) to produce inositol-1,4,5-trisphosphate, which is degraded to inositol monophosphate (IP1; phosphoinositide signaling). The potency of TSH for cAMP signaling is higher than for phosphoinositide signaling, and it was suggested that there are "spare receptors" for cAMP signaling. In a human embryonic kidney macrophage scavenger receptor-expressing (HEK-EM) 293 model system, there are no spare receptors, but the cells still exhibited 100-fold differences in potencies. Dose responses for TSH-stimulated dissociation of prebound (125)I-TSH (negative cooperativity; EC(50)=70 mU/ml), which requires TSH binding to both sites of the TSH receptor (TSHR) homodimer, and TSH-stimulated IP1 production (EC(50)=50 mU/ml) were indistinguishable. Fluorescence resonance energy transfer (FRET) using tagged receptors showed that TSHR formed homodimers and heterodimers with two binding-deficient mutant TSHRs, L252P and C41S. When L252P or C41S was expressed with TSHR, that is, when TSHR/L252P or TSHR/C41S heterodimers could only bind one TSH, TSH-stimulated IP1 production was decreased relative to cAMP production. The slopes of linear regression analyses comparing fold stimulation by TSH of IP1 vs. cAMP production were 0.044 ± 0.0047, 0.0043 ± 0.0041, and 0.0059 ± 0.0014 for cells expressing TSHR alone, TSHR and L252P, or TSHR and C41S, respectively. We suggest that TSHR coupling to phosphoinositide signaling is dependent on binding 2 molecules of TSH to TSHR homodimer, causing a conformational change allowing coupling to G(q/11).
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Affiliation(s)
- Michael D Allen
- Clinical Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-8029, USA
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35
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Łukasiewicz S, Faron-Górecka A, Kędracka-Krok S, Dziedzicka-Wasylewska M. Effect of clozapine on the dimerization of serotonin 5-HT(2A) receptor and its genetic variant 5-HT(2A)H425Y with dopamine D(2) receptor. Eur J Pharmacol 2011; 659:114-23. [PMID: 21496455 DOI: 10.1016/j.ejphar.2011.03.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 03/03/2011] [Accepted: 03/22/2011] [Indexed: 11/25/2022]
Abstract
Oligomerization of G protein-coupled receptors has become a very important issue in a present molecular pharmacology. In the present study the level of the serotonin 5-HT(2A) and the dopamine D(2) receptor interactions have been studied since it may have a key significance in understanding the mechanism of action of drugs used to treat schizophrenia. With the use of fluorescence resonance energy transfer we demonstrated that the serotonin 5-HT(2A) receptors form homo- and hetero-dimers with the dopamine D(2) receptors and polymorphism H452Y within the 5-HT(2A) receptor, implicated as a cause of altered response to antipsychotic treatment, disturbs both processes. Clozapine affected the hetero-dimers (5-HT(2A)H452Y/D(2)) complexes and increased the otherwise weakened dimerization to the value observed for combination of both wild type receptors, and had no effect on the serotonin receptor homo-dimers (5-HT(2A)H452Y/5-HT(2A)), while haloperidol has restored the weakened interaction within homo-complexes and did not effect the hetero-complexes. The obtained data suggest that H452Y polymorphism has an influence not only on the level of constitutive oligomerization of investigated receptors but also it changes their pharmacological properties within both homo- and hetero-complexes.
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Affiliation(s)
- Sylwia Łukasiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa Street, Krakow, Poland.
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36
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Smith NJ, Milligan G. Allostery at G protein-coupled receptor homo- and heteromers: uncharted pharmacological landscapes. Pharmacol Rev 2011; 62:701-25. [PMID: 21079041 DOI: 10.1124/pr.110.002667] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
For many years seven transmembrane domain G protein-coupled receptors (GPCRs) were thought to exist and function exclusively as monomeric units. However, evidence both from native cells and heterologous expression systems has demonstrated that GPCRs can both traffic and signal within higher-order complexes. As for other protein-protein interactions, conformational changes in one polypeptide, including those resulting from binding of pharmacological ligands, have the capacity to alter the conformation and therefore the response of the interacting protein(s), a process known as allosterism. For GPCRs, allosterism across homo- or heteromers, whether dimers or higher-order oligomers, represents an additional topographical landscape that must now be considered pharmacologically. Such effects may offer the opportunity for novel therapeutic approaches. Allosterism at GPCR heteromers is particularly exciting in that it offers additional scope to provide receptor subtype selectivity and tissue specificity as well as fine-tuning of receptor signal strength. Herein, we introduce the concept of allosterism at both GPCR homomers and heteromers and discuss the various questions that must be addressed before significant advances can be made in drug discovery at these GPCR complexes.
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Affiliation(s)
- Nicola J Smith
- Molecular Pharmacology Laboratory,University Avenue, University of Glasgow, Glasgow, Scotland
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Wade F, Espagne A, Persuy MA, Vidic J, Monnerie R, Merola F, Pajot-Augy E, Sanz G. Relationship between homo-oligomerization of a mammalian olfactory receptor and its activation state demonstrated by bioluminescence resonance energy transfer. J Biol Chem 2011; 286:15252-9. [PMID: 21454689 DOI: 10.1074/jbc.m110.184580] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G-protein-coupled receptor homo-oligomerization has been increasingly reported. However, little is known regarding the relationship between activation of the receptor and its association/conformational states. The mammalian olfactory receptors (ORs) belong to the G protein-coupled receptor superfamily. In this study, the homo-oligomerization status of the human OR1740 receptor and its involvement in receptor activation upon odorant ligand binding were addressed by co-immunoprecipitation and bioluminescence resonance energy transfer approaches using crude membranes or membranes from different cellular compartments. For the first time, our data clearly show that mammalian ORs constitutively self-associate into homodimers at the plasma membrane level. This study also demonstrates that ligand binding mediates a conformational change and promotes an inactive state of the OR dimers at high ligand concentrations. These findings support and validate our previously proposed model of OR activation/inactivation based on the tripartite odorant-binding protein-odorant-OR partnership.
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Affiliation(s)
- Fallou Wade
- UR1197 Neurobiologie de l'Olfaction et Modélisation en Imagerie, Institut National de la Recherche Agronomique, Domaine de Vilvert, F-78350 Jouy-en-Josas, France
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38
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Li X, Bachmanov AA, Maehashi K, Li W, Lim R, Brand JG, Beauchamp GK, Reed DR, Thai C, Floriano WB. Sweet taste receptor gene variation and aspartame taste in primates and other species. Chem Senses 2011; 36:453-75. [PMID: 21414996 DOI: 10.1093/chemse/bjq145] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Aspartame is a sweetener added to foods and beverages as a low-calorie sugar replacement. Unlike sugars, which are apparently perceived as sweet and desirable by a range of mammals, the ability to taste aspartame varies, with humans, apes, and Old World monkeys perceiving aspartame as sweet but not other primate species. To investigate whether the ability to perceive the sweetness of aspartame correlates with variations in the DNA sequence of the genes encoding sweet taste receptor proteins, T1R2 and T1R3, we sequenced these genes in 9 aspartame taster and nontaster primate species. We then compared these sequences with sequences of their orthologs in 4 other nontasters species. We identified 9 variant sites in the gene encoding T1R2 and 32 variant sites in the gene encoding T1R3 that distinguish aspartame tasters and nontasters. Molecular docking of aspartame to computer-generated models of the T1R2 + T1R3 receptor dimer suggests that species variation at a secondary, allosteric binding site in the T1R2 protein is the most likely origin of differences in perception of the sweetness of aspartame. These results identified a previously unknown site of aspartame interaction with the sweet receptor and suggest that the ability to taste aspartame might have developed during evolution to exploit a specialized food niche.
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Affiliation(s)
- Xia Li
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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39
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Albizu L, Moreno JL, González-Maeso J, Sealfon SC. Heteromerization of G protein-coupled receptors: relevance to neurological disorders and neurotherapeutics. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2011; 9:636-50. [PMID: 20632964 DOI: 10.2174/187152710793361586] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/30/2010] [Indexed: 11/22/2022]
Abstract
Because G protein-coupled receptors (GPCRs) are numerous, widely expressed and involved in major physiological responses, they represent a relevant therapeutic target for drug discovery, particularly regarding pharmacological treatments of neurological disorders. Among the biological phenomena regulating receptor function, GPCR heteromerization is an important emerging area of interest and investigation. There is increasing evidence showing that heteromerization contributes to the pharmacological heterogeneity of GPCRs by modulating receptor ontogeny, activation and recycling. Although in many cases the physiological relevance of receptor heteromerization has not been fully established, the unique pharmacological and functional properties of heteromers are likely to lead to new strategies in clinical medicine. This review describes the main GPCR heteromers and their implications for major neurological disorders such as Parkinson's disease, schizophrenia and addiction. A better understanding of molecular mechanisms underlying drug interactions related to the targeting of receptor heteromers could provide more specific and efficient therapeutic agents for the treatment of brain diseases.
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Affiliation(s)
- Laura Albizu
- Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA
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40
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Slinger E, Langemeijer E, Siderius M, Vischer HF, Smit MJ. Herpesvirus-encoded GPCRs rewire cellular signaling. Mol Cell Endocrinol 2011; 331:179-84. [PMID: 20398729 DOI: 10.1016/j.mce.2010.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 04/01/2010] [Indexed: 01/05/2023]
Abstract
Viral G-protein-coupled receptors (vGPCRs) are chemokine receptor homologues encoded by the Herpes- and Capripoxviridae. They are thought to have been hijacked from the host genome during the course of evolution. These vGPCRs play different roles in the viral lifecycle and associated pathologies. Three members of the Herpesviridae, Kaposi sarcoma-associated herpesvirus (KSHV), Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) are capable of setting up persistent latent infections in humans. Two of the herpesviruses, KSHV and EBV, are associated with cancer, while HCMV may have an oncomodulary effect. The vGPCRs may contribute to the escape of immune surveillance and (constitutively) activate signaling pathways linked to proliferation and inflammation. Some vGPCRs induce activation of autocrine and paracrine signaling, resulting in secretion of growth factors and/or cytokines. As a result, vGPCRs effectively rewire cellular signaling networks. Delineating the cellular signaling networks modulated by these vGPCRs will be crucial for treatment of virus-associated pathologies.
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Affiliation(s)
- Erik Slinger
- Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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Abstract
G protein-coupled receptors (GPCRs) comprise a large class of transmembrane proteins that play critical roles in both normal physiology and pathophysiology. These critical roles offer targets for therapeutic intervention, as exemplified by the substantial fraction of current pharmaceutical agents that target members of this family. Tremendous contributions to our understanding of GPCR structure and dynamics have come from both indirect and direct structural characterization techniques. Key features of GPCR conformations derived from both types of characterization techniques are reviewed.
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Affiliation(s)
- Abby L. Parrill
- Department of Chemistry, The University of Memphis, Memphis, TN 38152, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-901-678-2638; Fax: +1-901-678-3447
| | - Debra L. Bautista
- Christian Brothers High School, 5900 Walnut Grove Road, Memphis, TN 38120, USA; E-Mail: (D.L.B.)
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42
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Monnier C, Tu H, Bourrier E, Vol C, Lamarque L, Trinquet E, Pin JP, Rondard P. Trans-activation between 7TM domains: implication in heterodimeric GABAB receptor activation. EMBO J 2010; 30:32-42. [PMID: 21063387 DOI: 10.1038/emboj.2010.270] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 10/06/2010] [Indexed: 02/06/2023] Open
Abstract
Seven-transmembrane domain (7TM) receptors have important functions in cell-cell communication and can assemble into dimers or oligomers. Such complexes may allow specific functional cross-talk through trans-activation of interacting 7TMs, but this hypothesis requires further validation. Herein, we used the GABAB receptor, which is composed of two distinct subunits, GABAB1, which binds the agonist, and GABAB2, which activates G proteins, as a model system. By using a novel orthogonal-labelling approach compatible with time-resolved FRET and based on ACP- and SNAP-tag technologies to verify the heterodimerization of wild-type and mutated GABAB subunits, we demonstrate the existence of a direct allosteric coupling between the 7TMs of GABAB heterodimers. Indeed, a GABAB receptor, in which the GABAB2 extracellular domain was deleted, was still capable of activating G proteins. Furthermore, synthetic ligands for the GABAB2 7TM could increase agonist affinity at the GABAB1 subunit in this mutated receptor. In addition to bringing new information on GABAB receptor activation, these data clearly demonstrate the existence of direct trans-activation between the 7TM of two interacting proteins.
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Affiliation(s)
- Carine Monnier
- CNRS, UMR 5203, Institut de Génomique Fonctionnelle, Département de Pharmacologie Moléculaire, Montpellier, France
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43
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Darbandi-Tehrani K, Hermand P, Carvalho S, Dorgham K, Couvineau A, Lacapère JJ, Combadière C, Deterre P. Subtle conformational changes between CX3CR1 genetic variants as revealed by resonance energy transfer assays. FASEB J 2010; 24:4585-98. [PMID: 20667981 DOI: 10.1096/fj.10-156612] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The chemokine CX3CL1 is expressed as a membrane protein that forms a potent adhesive pair with its unique receptor CX3CR1. This receptor has 3 natural variants, V249-T280 (VT), I249-T280 (IT), and I249-M280 (IM), whose relative frequencies are significantly associated with the incidence of various inflammatory diseases. To assess the adhesive potency of CX3CR1 and the molecular diversity of its variants, we assayed their clustering status and their possible structural differences by fluorescence/bioluminescence resonance energy transfer (FRET or BRET) techniques. FRET assays by flow cytometry showed that the CX3CR1 variants cluster, in comparison with appropriate controls. BRET assays showed low nonspecific signals for VT and IT variants and high specific signals for IM, and thus pointed out a structural difference in this variant. We used molecular modeling to show how natural point mutations of CX3CR1 affect the packing of the 6th and 7th helices of this G-protein coupled receptor. Moreover, we found that the BRET technique is sensitive enough to detect these tiny changes. Consistently with our previous finding that CX3CL1 aggregates, our data here indicate that CX3CR1 clustering may contribute to the adhesiveness of the CX3CL1-CX3CR1 pair and may thus represent a new target for anti-inflammatory therapies.
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44
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Birdsall NJM. Class A GPCR heterodimers: evidence from binding studies. Trends Pharmacol Sci 2010; 31:499-508. [PMID: 20870299 DOI: 10.1016/j.tips.2010.08.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 11/26/2022]
Abstract
There is a large body of experimental evidence that is compatible with the presence of heterodimers of the major A subclass of G protein-coupled receptors (GPCRs) and suggests that these heterodimers might have different functional properties from those of the monomers (or homodimers) of the individual receptors that engage in heterodimer formation. The question is whether there are allosteric interactions across the receptor-receptor interface of a heterodimer that modulate the binding properties of the heterodimer components and thereby change their pharmacology. In this review, I examine published experimental evidence from radioligand binding studies in the context of different models of allosterism and discuss a number of apparently discrepant results. The analysis suggests that more experimental data are required if equal, two-way, crossreceptor interactions within a GPCR heterodimer, at the level of binding, are to be unequivocally demonstrated.
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Affiliation(s)
- Nigel J M Birdsall
- Division of Physical Biochemistry, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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45
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An in vivo demonstration of functional G protein-coupled receptor dimers. Proc Natl Acad Sci U S A 2010; 107:1819-20. [PMID: 20133832 DOI: 10.1073/pnas.0914432107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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46
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Direct interaction of GABAB receptors with M2 muscarinic receptors enhances muscarinic signaling. J Neurosci 2010; 29:15796-809. [PMID: 20016095 DOI: 10.1523/jneurosci.4103-09.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Downregulation of G-protein-coupled receptors (GPCRs) provides an important mechanism for reducing neurotransmitter signaling during sustained stimulation. Chronic stimulation of M(2) muscarinic receptors (M(2)Rs) causes internalization of M(2)R and G-protein-activated inwardly rectifying potassium (GIRK) channels in neuronal PC12 cells, resulting in loss of function. Here, we show that coexpression of GABA(B) R2 receptors (GBR2s) rescues both surface expression and function of M(2)R, including M(2)R-induced activation of GIRKs and inhibition of cAMP production. GBR2 showed significant association with M(2)R at the plasma membrane but not other GPCRs (M(1)R, mu-opioid receptor), as detected by fluorescence resonance energy transfer measured with total internal reflection fluorescence microscopy. Unique regions of the proximal C-terminal domains of GBR2 and M(2)R mediate specific binding between M(2)R and GBR2. In the brain, GBR2, but not GBR1, biochemically coprecipitates with M(2)R and overlaps with M(2)R expression in cortical neurons. This novel heteromeric association between M(2)R and GBR2 provides a possible mechanism for altering muscarinic signaling in the brain and represents a previously unrecognized role for GBR2.
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47
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Valant C, Maillet E, Bourguignon JJ, Bucher B, Utard V, Galzi JL, Hibert M. Allosteric functional switch of neurokinin A-mediated signaling at the neurokinin NK2 receptor: structural exploration. J Med Chem 2009; 52:5999-6011. [PMID: 19746979 DOI: 10.1021/jm900671k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The neurokinin NK2 receptor is known to pre-exist in equilibrium between at least three states: resting-inactive, calcium-triggering, and cAMP-producing. Its endogeneous ligand, NKA, mainly induces the calcium response. Using a FRET-based assay, we have previously discovered an allosteric modulator of the NK2 receptor that has the unique ability to discriminate among the two signaling pathways: calcium-signaling is not affected while cAMP signaling is significantly decreased. A series of compounds have been prepared and studied in order to better understand the structural determinants of this allosteric functional switch of a GPCR. Most of them display the same allosteric profile, with smooth pharmacomodulation. One compound however exhibits significantly improved modulatory properties of NKA induced signaling when compared to the original modulator.
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Affiliation(s)
- Céline Valant
- UMR UdS/CNRS 7200, Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, Illkirch, France
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48
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Guan R, Wu X, Feng X, Zhang M, Hébert TE, Segaloff DL. Structural determinants underlying constitutive dimerization of unoccupied human follitropin receptors. Cell Signal 2009; 22:247-56. [PMID: 19800402 DOI: 10.1016/j.cellsig.2009.09.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 09/14/2009] [Indexed: 01/07/2023]
Abstract
The human follitropin receptor (hFSHR) is a G protein-coupled receptor (GPCR) central to reproductive physiology that is composed of an extracellular domain (ECD) fused to a serpentine region. Using bioluminescence resonance energy transfer (BRET) in living cells, we show that hFSHR dimers form constitutively during their biosynthesis. Mutations in TM1 and TM4 had no effect on hFSHR dimerization, alone or when combined with mutation of Tyr(110) in the ECD, a residue predicted to mediate dimerization of the soluble hormone-binding portion of the ECD complexed with FSH (Q. Fan and W. Hendrickson, Nature 433:269-277, 2005). Expressed individually, the serpentine region and a membrane-anchored form of the hFSHR ECD each exhibited homodimerization, suggesting that both domains contribute to dimerization of the full-length receptor. However, even in the context of only the membrane-anchored ECD, mutation of Tyr(110) to alanine did not inhibit dimerization. The full-length hFSHR and the membrane-anchored ECD were then each engineered to introduce a consensus site for N-linked glycosylation at residue 110. Despite experimental validation of the presence of carbohydrate on residue 110, we failed to observe disruption of dimerization of either the full-length hFSHR or membrane-anchored ECD containing the inserted glycan wedge. Taken altogether, our data suggest that both the serpentine region and the ECD contribute to hFSHR dimerization and that the dimerization interface of the unoccupied hFSHR does not involve Tyr(110) of the ECD.
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Affiliation(s)
- Rongbin Guan
- Department of Molecular Physiology and Biophysics, The University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, United States
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Sohy D, Yano H, de Nadai P, Urizar E, Guillabert A, Javitch JA, Parmentier M, Springael JY. Hetero-oligomerization of CCR2, CCR5, and CXCR4 and the protean effects of "selective" antagonists. J Biol Chem 2009; 284:31270-9. [PMID: 19758998 DOI: 10.1074/jbc.m109.054809] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chemokine receptors constitute an attractive family of drug targets in the frame of inflammatory diseases. However, targeting specific chemokine receptors may be complicated by their ability to form dimers or higher order oligomers. Using a combination of luminescence complementation and bioluminescence resonance energy transfer assays, we demonstrate for the first time the existence of hetero-oligomeric complexes composed of at least three chemokine receptors (CCR2, CCR5, and CXCR4). We show in T cells and monocytes that negative binding cooperativity takes place between the binding pockets of these receptors, demonstrating their functional interaction in leukocytes. We also show that specific antagonists of one receptor (TAK-779 or AMD3100) lead to functional cross-inhibition of the others. Finally, using the air pouch model in mice, we show that the CCR2 and CCR5 antagonist TAK-779 inhibits cell recruitment promoted by the CXCR4 agonist SDF-1 alpha, demonstrating that cross-inhibition by antagonists also occurs in vivo. Thus, antagonists of the therapeutically important chemokine receptors regulate the functional properties of other receptors to which they do not bind directly with important implications for the use of these agents in vivo.
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Affiliation(s)
- Denis Sohy
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, B-1070 Brussels, Belgium
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50
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Allosteric communication between protomers of dopamine class A GPCR dimers modulates activation. Nat Chem Biol 2009; 5:688-95. [PMID: 19648932 PMCID: PMC2817978 DOI: 10.1038/nchembio.199] [Citation(s) in RCA: 285] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 04/28/2009] [Indexed: 01/09/2023]
Abstract
A major obstacle to understanding the functional importance of dimerization between Class A G protein-coupled receptors (GPCRs) has been the methodological limitation in achieving control of the identity of the components comprising the signaling unit. We have developed a functional complementation assay that enables such control and illustrate it for the human dopamine D2 receptor. The minimal signaling unit, two receptors and a single G protein, is maximally activated by agonist binding to a single protomer, which suggests an asymmetrical activated dimer. Inverse agonist binding to the second protomer enhances signaling, whereas agonist binding to the second protomer blunts signaling. Ligand-independent constitutive activation of the second protomer also inhibits signaling. Thus, GPCR dimer function can be modulated by the activity state of the second protomer, which for a heterodimer may be altered in pathological states. Our novel methodology also makes possible the characterization of signaling from a defined heterodimer unit.
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