1
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Chen J, Gou Q, Chen X, Song Y, Zhang F, Pu X. Exploring biased activation characteristics by molecular dynamics simulation and machine learning for the μ-opioid receptor. Phys Chem Chem Phys 2024; 26:10698-10710. [PMID: 38512140 DOI: 10.1039/d3cp05050e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Biased ligands selectively activating specific downstream signaling pathways (termed as biased activation) exhibit significant therapeutic potential. However, the conformational characteristics revealed are very limited for the biased activation, which is not conducive to biased drug development. Motivated by the issue, we combine extensive accelerated molecular dynamics simulations and an interpretable deep learning model to probe the biased activation features for two complex systems constructed by the inactive μOR and two different biased agonists (G-protein-biased agonist TRV130 and β-arrestin-biased agonist endomorphin2). The results indicate that TRV130 binds deeper into the receptor core compared to endomorphin2, located between W2936.48 and D1142.50, and forms hydrogen bonding with D1142.50, while endomorphin2 binds above W2936.48. The G protein-biased agonist induces greater outward movements of the TM6 intracellular end, forming a typical active conformation, while the β-arrestin-biased agonist leads to a smaller extent of outward movements of TM6. Compared with TRV130, endomorphin2 causes more pronounced inward movements of the TM7 intracellular end and more complex conformational changes of H8 and ICL1. In addition, important residues determining the two different biased activation states were further identified by using an interpretable deep learning classification model, including some common biased activation residues across Class A GPCRs like some key residues on the TM2 extracellular end, ECL2, TM5 intracellular end, TM6 intracellular end, and TM7 intracellular end, and some specific important residues of ICL3 for μOR. The observations will provide valuable information for understanding the biased activation mechanism for GPCRs.
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Affiliation(s)
- Jianfang Chen
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Qiaoling Gou
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Xin Chen
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Yuanpeng Song
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Fuhui Zhang
- Graduate School, Sichuan University, Chengdu 610064, China
| | - Xuemei Pu
- College of Chemistry, Sichuan University, Chengdu 610064, China.
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2
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Théroux L, Van Den Hauwe R, Trân K, Fournier J, Desgagné M, Meneboo N, Lavallée A, Fröhlich U, Côté J, Hollanders C, Longpré JM, Murza A, Marsault E, Sarret P, Boudreault PL, Ballet S. Signaling Modulation via Minimal C-Terminal Modifications of Apelin-13. ACS Pharmacol Transl Sci 2023; 6:290-305. [PMID: 36798478 PMCID: PMC9926529 DOI: 10.1021/acsptsci.2c00219] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Indexed: 01/27/2023]
Abstract
Apelin is an endogenous peptide that is involved in many diseases such as cardiovascular diseases, obesity, and cancer, which has made it an attractive target for drug discovery. Herein, we explore the penultimate and final sequence positions of [Pyr1]-apelin-13 (Ape13) via C-terminal N α-alkylated amide bonds and the introduction of positive charges, potentially targeting the allosteric sodium pocket, by assessing the binding affinity and signaling profiles at the apelin receptor (APJ). Synthetic analogues modified within this segment of Ape13 showed high affinity (K i 0.12-0.17 nM vs Ape13 K i 0.7 nM), potent Gαi1 activation (EC50 Gαi1 0.4-0.9 nM vs Ape13 EC50 1.1 nM), partial agonist behavior disfavoring β-arrestin 2 recruitment for positively charged ligands (e.g., 49 (SBL-AP-058), EC50 β-arr2 275 nM, E max 54%) and high plasma stability for N-alkyl ligands (t 1/2 > 7 h vs Ape13 t 1/2 0.5 h). Combining the benefits of the N α-alkylated amide bond with the guanidino substitution in a constrained ligand led to 63 (SBL-AP-049), which displayed increased plasma stability (t 1/2 5.3 h) and strong reduction of β-arrestin 2 signaling with partial maximal efficacy (EC50 β-arr 864 nM, E max 48%), significantly reducing the hypotensive effect in vivo.
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Affiliation(s)
- Léa Théroux
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Robin Van Den Hauwe
- Research
Group of Organic Chemistry, Departments of Chemistry and Bioengineering
Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Kien Trân
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Justin Fournier
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Michael Desgagné
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Nathan Meneboo
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Alexis Lavallée
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Ulrike Fröhlich
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Jérôme Côté
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Charlie Hollanders
- Research
Group of Organic Chemistry, Departments of Chemistry and Bioengineering
Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jean-Michel Longpré
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Alexandre Murza
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Eric Marsault
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Philippe Sarret
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Pierre-Luc Boudreault
- Département
de Pharmacologie-Physiologie, Faculté de Médecine et
des Sciences de la Santé, Université
de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Steven Ballet
- Research
Group of Organic Chemistry, Departments of Chemistry and Bioengineering
Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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3
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Zhang Z, Zhang Q, Dexheimer TS, Ren J, Neubig RR, Li W. Two highly related odorant receptors specifically detect α-bile acid pheromones in sea lamprey ( Petromyzon marinus). J Biol Chem 2020; 295:12153-12166. [PMID: 32636305 PMCID: PMC7443511 DOI: 10.1074/jbc.ra119.011532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 07/01/2020] [Indexed: 10/23/2022] Open
Abstract
Pheromones play critical roles in habitat identification and reproductive behavior synchronization in the sea lamprey (Petromyzon marinus). The bile acid 3-keto petromyzonol sulfate (3kPZS) is a major component of the sex pheromone mixture from male sea lamprey that induces specific olfactory and behavioral responses in conspecific individuals. Olfactory receptors interact directly with pheromones, which is the first step in their detection, but identifying the cognate receptors of specific pheromones is often challenging. Here, we deorphanized two highly related odorant receptors (ORs), OR320a and OR320b, of P. marinus that respond to 3kPZS. In a heterologous expression system coupled to a cAMP-responsive CRE-luciferase, OR320a and OR320b specifically responded to C24 5α-bile acids, and both receptors were activated by the same set of 3kPZS analogs. OR320a displayed larger responses to all 3kPZS analogs than did OR320b. This difference appeared to be largely determined by a single amino acid residue, Cys-792.56, the C-terminal sixth residue relative to the most conserved residue in the second transmembrane domain (2.56) of OR320a. This region of TM2 residues 2.56-2.60 apparently is critical for the detection of steroid compounds by odorant receptors in lamprey, zebrafish, and humans. Finally, we identified OR320 orthologs in Japanese lamprey (Lethenteron camtschaticum), suggesting that the OR320 family may be widely present in lamprey species and that OR320 may be under purifying selection. Our results provide a system to examine the origin of olfactory steroid detection in vertebrates and to define a highly conserved molecular mechanism for steroid-ligand detection by G protein-coupled receptors.
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Affiliation(s)
- Zhe Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, China
| | - Qinghua Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, China
| | - Thomas S Dexheimer
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Jianfeng Ren
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, China
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA.
| | - Weiming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, USA.
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4
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Hu X, Smith MD, Humphreys BM, Green AT, Parks JM, Baudry JY, Smith JC. Ligand-Dependent Sodium Ion Dynamics within the A 2A Adenosine Receptor: A Molecular Dynamics Study. J Phys Chem B 2019; 123:7947-7954. [PMID: 31483659 DOI: 10.1021/acs.jpcb.9b04474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Sodium ions have long been known to reduce the binding of agonists in many class-A GPCRs while having little effect on antagonist binding. Here, using long-time scale classical all-atom molecular dynamics simulations, we explore, in atomic detail, the motion of sodium ions within the ligand-binding pocket of the A2A adenosine receptor (A2A-AR) both in the presence and absence of ligands and in the active and inactive state. We identify novel secondary ion binding sites within the pocket and find that the types of ion motions within the pocket are highly dependent on the presence and type of ligand within the pocket. Our results provide a first step toward developing a molecular understanding of the impact of sodium ions on class-A GPCRs.
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Affiliation(s)
- Xiaohu Hu
- Department of Pharmacological Sciences , Icahn School of Medicine at Mount Sinai , New York , New York 10029 , United States.,Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Micholas Dean Smith
- Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Bailey M Humphreys
- Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Adam T Green
- Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Jerry M Parks
- Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Jerome Y Baudry
- Biological Sciences Department , University of Alabama in Huntsville , Huntsville , Alabama 35899 , United States
| | - Jeremy C Smith
- Center for Molecular Biophysics, Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
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5
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Chen S, Lu M, Liu D, Yang L, Yi C, Ma L, Zhang H, Liu Q, Frimurer TM, Wang MW, Schwartz TW, Stevens RC, Wu B, Wüthrich K, Zhao Q. Human substance P receptor binding mode of the antagonist drug aprepitant by NMR and crystallography. Nat Commun 2019; 10:638. [PMID: 30733446 PMCID: PMC6367319 DOI: 10.1038/s41467-019-08568-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/11/2019] [Indexed: 12/30/2022] Open
Abstract
Neurokinin 1 receptor (NK1R) has key regulating functions in the central and peripheral nervous systems, and NK1R antagonists such as aprepitant have been approved for treating chemotherapy-induced nausea and vomiting. However, the lack of data on NK1R structure and biochemistry has limited further drug development targeting this receptor. Here, we combine NMR spectroscopy and X-ray crystallography to provide dynamic and static characterisation of the binding mode of aprepitant in complexes with human NK1R variants. 19F-NMR showed a slow off-rate in the binding site, where aprepitant occupies multiple substates that exchange with frequencies in the millisecond range. The environment of the bound ligand is affected by the amino acid in position 2.50, which plays a key role in ligand binding and receptor signaling in class A GPCRs. Crystal structures now reveal how receptor signaling relates to the conformation of the conserved NP7.50xxY motif in transmembrane helix VII. The FDA approved drug aprepitant is an antagonist of the Neurokinin 1 receptor (NK1R). Here the authors present aprepitant bound NK1R crystal structures and use NMR spectroscopy to gain further insights into the dynamics of aprepitant binding, which is of interest for further drug development.
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Affiliation(s)
- Shuanghong Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Mengjie Lu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Dongsheng Liu
- iHuman Institute, Shanghai Tech University, 393 Hua Xia Zhong Road, Shanghai, 201210, China
| | - Lingyun Yang
- iHuman Institute, Shanghai Tech University, 393 Hua Xia Zhong Road, Shanghai, 201210, China
| | - Cuiying Yi
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Limin Ma
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Hui Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Qing Liu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Pudong, Shanghai, 201203, China
| | - Thomas M Frimurer
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3b, Copenhagen, 2200, Denmark
| | - Ming-Wei Wang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China.,The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Pudong, Shanghai, 201203, China.,School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai, 201203, China.,School of Life Science and Technology, ShanghaiTech University, 393 Hua Xia Zhong Road, Pudong, Shanghai, 201210, China
| | - Thue W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3b, Copenhagen, 2200, Denmark
| | - Raymond C Stevens
- iHuman Institute, Shanghai Tech University, 393 Hua Xia Zhong Road, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, 393 Hua Xia Zhong Road, Pudong, Shanghai, 201210, China
| | - Beili Wu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. .,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China. .,School of Life Science and Technology, ShanghaiTech University, 393 Hua Xia Zhong Road, Pudong, Shanghai, 201210, China. .,CAS Center for Excellence in Biomacromolecules, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Kurt Wüthrich
- iHuman Institute, Shanghai Tech University, 393 Hua Xia Zhong Road, Shanghai, 201210, China. .,School of Life Science and Technology, ShanghaiTech University, 393 Hua Xia Zhong Road, Pudong, Shanghai, 201210, China. .,Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| | - Qiang Zhao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai, 201203, China. .,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. .,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China. .,CAS Center for Excellence in Biomacromolecules, Chinese Academy of Sciences, Beijing, 100101, China.
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6
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Modestia SM, Malta de Sá M, Auger E, Trossini GHG, Krieger JE, Rangel-Yagui CDO. Biased Agonist TRV027 Determinants in AT1R by Molecular Dynamics Simulations. J Chem Inf Model 2019; 59:797-808. [PMID: 30668103 DOI: 10.1021/acs.jcim.8b00628] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Functional selectivity is a phenomenon observed in G protein-coupled receptors in which intermediate active-state conformations are stabilized by mutations or ligand binding, resulting in different sets of signaling pathways. Peptides capable of selectively activating β-arrestin, known as biased agonists, have already been characterized in vivo and could correspond to a new therapeutic approach for treatment of cardiovascular diseases. Despite the potential of biased agonism, the mechanism involved in selective signaling remains unclear. In this work, molecular dynamics simulations were employed to compare the conformational profile of the angiotensin II type 1 receptor (AT1R) crystal bound to angiotensin II, bound to the biased ligand TRV027, and in the apo form. Our results show that both ligands induce changes near the NPxxY motif in transmembrane domain 7 that are related to receptor activation. However, the biased ligand does not cause the rotamer toggle alternative positioning and displays an exclusive hydrogen-bonding pattern. Our work sheds light on the biased agonism mechanism and will help in the future design of novel biased agonists for AT1R.
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Affiliation(s)
- Silvestre Massimo Modestia
- Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutical Sciences , University of São Paulo , Av. Prof. Lineu Prestes 580 , 05508-900 São Paulo - SP , Brazil
| | - Matheus Malta de Sá
- Laboratory of Genetics and Molecular Cardiology, Heart Institute , University of São Paulo Medical School , Av. Dr. Enéas de Carvalho Aguiar 44 , 05403-900 São Paulo - SP , Brazil
| | - Eric Auger
- Laboratory of Genetics and Molecular Cardiology, Heart Institute , University of São Paulo Medical School , Av. Dr. Enéas de Carvalho Aguiar 44 , 05403-900 São Paulo - SP , Brazil
| | - Gustavo Henrique Goulart Trossini
- Department of Pharmacy, School of Pharmaceutical Sciences , University of São Paulo , Av. Prof. Lineu Prestes 580 , 05508-900 São Paulo - SP , Brazil
| | - José Eduardo Krieger
- Laboratory of Genetics and Molecular Cardiology, Heart Institute , University of São Paulo Medical School , Av. Dr. Enéas de Carvalho Aguiar 44 , 05403-900 São Paulo - SP , Brazil
| | - Carlota de Oliveira Rangel-Yagui
- Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutical Sciences , University of São Paulo , Av. Prof. Lineu Prestes 580 , 05508-900 São Paulo - SP , Brazil
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7
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Singh KD, Unal H, Desnoyer R, Karnik SS. Mechanism of Hormone Peptide Activation of a GPCR: Angiotensin II Activated State of AT 1R Initiated by van der Waals Attraction. J Chem Inf Model 2019; 59:373-385. [PMID: 30608150 DOI: 10.1021/acs.jcim.8b00583] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We present a succession of structural changes involved in hormone peptide activation of a prototypical GPCR. Microsecond molecular dynamics simulation generated conformational ensembles reveal propagation of structural changes through key "microswitches" within human AT1R bound to native hormone. The endocrine octa-peptide angiotensin II (AngII) activates AT1R signaling in our bodies which maintains physiological blood pressure, electrolyte balance, and cardiovascular homeostasis. Excessive AT1R activation is associated with pathogenesis of hypertension and cardiovascular diseases which are treated by sartan drugs. The mechanism of AT1R inhibition by sartans has been elucidated by 2.8 Å X-ray structures, mutagenesis, and computational analyses. Yet, the mechanism of AT1R activation by AngII is unclear. The current study delineates an activation scheme initiated by AngII binding. A van der Waals "grasp" interaction between Phe8AngII with Ile2887.39 in AT1R induced mechanical strain pulling Tyr2927.43 and breakage of critical interhelical H-bonds, first between Tyr2927.43 and Val1083.32 and second between Asn1113.35 and Asn2957.46. Subsequently changes are observed in conserved microswitches DRYTM3, Yx7K(R)TM5, CWxPTM6, and NPxxYTM7 in AT1R. Activating the microswitches in the intracellular region of AT1R may trigger formation of the G-protein binding pocket as well as exposure of helix-8 to cytoplasm. Thus, the active-like conformation of AT1R is initiated by the van der Waals interaction of Phe8AngII with Ile2887.39, followed by systematic reorganization of critical interhelical H-bonds and activation of microswitches.
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Affiliation(s)
- Khuraijam Dhanachandra Singh
- Department of Molecular Cardiology, Lerner Research Institute , Cleveland Clinic Foundation , Cleveland , Ohio 44195 , United States
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute , Cleveland Clinic Foundation , Cleveland , Ohio 44195 , United States
| | - Russell Desnoyer
- Department of Molecular Cardiology, Lerner Research Institute , Cleveland Clinic Foundation , Cleveland , Ohio 44195 , United States
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute , Cleveland Clinic Foundation , Cleveland , Ohio 44195 , United States
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8
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Allosteric sodium binding cavity in GPR3: a novel player in modulation of Aβ production. Sci Rep 2018; 8:11102. [PMID: 30038319 PMCID: PMC6056553 DOI: 10.1038/s41598-018-29475-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 07/10/2018] [Indexed: 01/01/2023] Open
Abstract
The orphan G-protein coupled receptor 3 (GPR3) belongs to class A G-protein coupled receptors (GPCRs) and is highly expressed in central nervous system neurons. Among other functions, it is likely associated with neuron differentiation and maturation. Recently, GPR3 has also been linked to the production of Aβ peptides in neurons. Unfortunately, the lack of experimental structural information for this receptor hampers a deep characterization of its function. Here, using an in-silico and in-vitro combined approach, we describe, for the first time, structural characteristics of GPR3 receptor underlying its function: the agonist binding site and the allosteric sodium binding cavity. We identified and validated by alanine-scanning mutagenesis the role of three functionally relevant residues: Cys2676.55, Phe1203.36 and Asp2.50. The latter, when mutated into alanine, completely abolished the constitutive and agonist-stimulated adenylate cyclase activity of GPR3 receptor by disrupting its sodium binding cavity. Interestingly, this is correlated with a decrease in Aβ production in a model cell line. Taken together, these results suggest an important role of the allosteric sodium binding site for GPR3 activity and open a possible avenue for the modulation of Aβ production in the Alzheimer’s Disease.
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9
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Schiffmann A, Gimpl G. Sodium functions as a negative allosteric modulator of the oxytocin receptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [PMID: 29524392 DOI: 10.1016/j.bbamem.2018.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The oxytocin receptor, a class A G protein coupled receptor (GPCR), is essentially involved in the physiology of reproduction. Two parameters are crucially important to support high-affinity agonist binding of the receptor: Mg2+ and cholesterol, both acting as positive modulators. Using displacement assays with a high-affinity fluorescent antagonist (OTAN-A647), we now show that sodium functions as a negative allosteric modulator of the oxytocin receptor. In membranes from HEK293 cells stably expressing the oxytocin receptor, oxytocin binding occurred with about 15-fold lower affinity when sodium chloride was increased from 0 to 300 mM, whereas antagonist binding remained largely unchanged. The effect was concentration-dependent, sodium-specific, and it was also observed for oxytocin receptors endogenously expressed in Hs578T breast cancer cells. A conserved Asp (Asp 85) is known to stabilize the sodium binding site in other GCPRs. Mutations of this residue into Ala or Asn are known to yield non-functional oxytocin receptors. When Asp 85 was exchanged for Glu, most of the oxytocin receptors were localized in intracellular structures, but a faint plasma membrane labeling with OTAN-A647 and the appearance of oxytocin-induced calcium responses indicated that these receptors were functional. However, a sodium effect was not detectable for the mutant D85E oxytocin receptors. Thus, the oxytocin receptor is allosterically controlled by sodium similar to other GPCRs, but it behaves differently concerning the involvement of the conserved Asp 85. In case of the oxytocin receptor, Asp 85 is obviously essential for proper localization in the plasma membrane.
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Affiliation(s)
- Andrea Schiffmann
- Johannes-Gutenberg University Mainz, Institute of Biochemistry, Johann-Joachim Becherweg 30, 55128 Mainz, Germany
| | - Gerald Gimpl
- Johannes-Gutenberg University Mainz, Institute of Biochemistry, Johann-Joachim Becherweg 30, 55128 Mainz, Germany.
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10
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Eddy MT, Lee MY, Gao ZG, White KL, Didenko T, Horst R, Audet M, Stanczak P, McClary KM, Han GW, Jacobson KA, Stevens RC, Wüthrich K. Allosteric Coupling of Drug Binding and Intracellular Signaling in the A 2A Adenosine Receptor. Cell 2018; 172:68-80.e12. [PMID: 29290469 PMCID: PMC5766378 DOI: 10.1016/j.cell.2017.12.004] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 09/05/2017] [Accepted: 11/30/2017] [Indexed: 10/18/2022]
Abstract
Signaling across cellular membranes, the 826 human G protein-coupled receptors (GPCRs) govern a wide range of vital physiological processes, making GPCRs prominent drug targets. X-ray crystallography provided GPCR molecular architectures, which also revealed the need for additional structural dynamics data to support drug development. Here, nuclear magnetic resonance (NMR) spectroscopy with the wild-type-like A2A adenosine receptor (A2AAR) in solution provides a comprehensive characterization of signaling-related structural dynamics. All six tryptophan indole and eight glycine backbone 15N-1H NMR signals in A2AAR were individually assigned. These NMR probes provided insight into the role of Asp522.50 as an allosteric link between the orthosteric drug binding site and the intracellular signaling surface, revealing strong interactions with the toggle switch Trp 2466.48, and delineated the structural response to variable efficacy of bound drugs across A2AAR. The present data support GPCR signaling based on dynamic interactions between two semi-independent subdomains connected by an allosteric switch at Asp522.50.
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Affiliation(s)
- Matthew T Eddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Ming-Yue Lee
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Zhan-Guo Gao
- Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kate L White
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Tatiana Didenko
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Reto Horst
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Pfizer Worldwide Research and Development, Eastern Point Road, Groton, CT 06340, USA
| | - Martin Audet
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Pawel Stanczak
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kyle M McClary
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Gye Won Han
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Kenneth A Jacobson
- Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Raymond C Stevens
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Kurt Wüthrich
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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11
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Abstract
The renin-angiotensin system (RAS) is a key regulator of blood pressure and blood volume homeostasis. The RAS is primarily comprised of the precursor protein angiotensinogen and the two proteases, renin and angiotensin-converting enzyme (ACE). Angiotensin I (Ang I) is derived from angiotensinogen by renin, but appears to have no biological activity. In contrast, angiotensin II (Ang II) that has a variety of biological functions in the cells is converted from Ang I through removal of two-C-terminal residues by ACE. The physiological effects of Ang II are due to Ang II signaling through specific receptor binding, resulting in muscle contraction leading to increased blood pressure and volume. To modulate RAS, three classes of drugs have been developed: (1) renin inhibitors to prevent angiotensinogen conversion to Ang I, (2) ACE inhibitors, to prevent Ang I processing to Ang II and (3) angiotensin receptor blockers, to inhibit Ang II signaling through its receptor. Studies using the RAS inhibitors and Ang II demonstrated that RAS signaling mediates actions of Ang II in the regulation of proliferation and differentiation of specific hematopoietic cell types, especially in the red blood cell lineage. Accumulating evidence indicates that RAS regulates EPO, an essential mediator of red cell production, for human anemia and erythropoiesis in vivo and in vitro. The regulation of EPO expression by Ang II may be responsible for maintaining red blood cell homeostasis. This review highlights the biological roles of RAS for blood cell and EPO homeostasis through Ang II signaling. The molecular mechanism for Ang II-induced EPO production of the cell or tissue type-specific expression is discussed.
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Affiliation(s)
- Yong-Chul Kim
- Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Ognoon Mungunsukh
- Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Regina M Day
- Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
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12
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Hunyady L, Gáborik Z, Vauquelin G, Catt KJ. Review: Structural requirements for signalling and regulation of AT1-receptors. J Renin Angiotensin Aldosterone Syst 2016; 2:S16-S23. [DOI: 10.1177/14703203010020010301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- László Hunyady
- Department of Physiology, Semmelweis University Medical
School, Budapest, Hungary,
| | - Zsuzsanna Gáborik
- Department of Physiology, Semmelweis University Medical
School, Budapest, Hungary
| | - Georges Vauquelin
- Department of Molecular and Biochemical Pharmacology,
Institute of Molecular Biology and Biotechnology, Free University of Brussels
(VUB), Sint-Genesius Rode, Belgium
| | - Kevin J Catt
- Endocrinology and Reproduction Research Branch, National
Institute of Child Health and Human Development, National Institutes of Health,
Bethesda, USA
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13
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Zhang H, Unal H, Desnoyer R, Han GW, Patel N, Katritch V, Karnik SS, Cherezov V, Stevens RC. Structural Basis for Ligand Recognition and Functional Selectivity at Angiotensin Receptor. J Biol Chem 2015; 290:29127-39. [PMID: 26420482 DOI: 10.1074/jbc.m115.689000] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 12/23/2022] Open
Abstract
Angiotensin II type 1 receptor (AT1R) is the primary blood pressure regulator. AT1R blockers (ARBs) have been widely used in clinical settings as anti-hypertensive drugs and share a similar chemical scaffold, although even minor variations can lead to distinct therapeutic efficacies toward cardiovascular etiologies. The structural basis for AT1R modulation by different peptide and non-peptide ligands has remained elusive. Here, we report the crystal structure of the human AT1R in complex with an inverse agonist olmesartan (Benicar(TM)), a highly potent anti-hypertensive drug. Olmesartan is anchored to the receptor primarily by the residues Tyr-35(1.39), Trp-84(2.60), and Arg-167(ECL2), similar to the antagonist ZD7155, corroborating a common binding mode of different ARBs. Using docking simulations and site-directed mutagenesis, we identified specific interactions between AT1R and different ARBs, including olmesartan derivatives with inverse agonist, neutral antagonist, or agonist activities. We further observed that the mutation N111(3.35)A in the putative sodium-binding site affects binding of the endogenous peptide agonist angiotensin II but not the β-arrestin-biased peptide TRV120027.
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Affiliation(s)
- Haitao Zhang
- From the Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089 and
| | - Hamiyet Unal
- the Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio 44195
| | - Russell Desnoyer
- the Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio 44195
| | - Gye Won Han
- Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089 and
| | | | | | - Sadashiva S Karnik
- the Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio 44195
| | - Vadim Cherezov
- Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089 and
| | - Raymond C Stevens
- From the Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089 and
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14
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Ranganathan A, Dror RO, Carlsson J. Insights into the Role of Asp792.50 in β2 Adrenergic Receptor Activation from Molecular Dynamics Simulations. Biochemistry 2014; 53:7283-96. [DOI: 10.1021/bi5008723] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anirudh Ranganathan
- Science for Life Laboratory, Box 1031, SE-171 21 Solna, Sweden
- Department
of Biochemistry and Biophysics and Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ron O. Dror
- Department
of Computer Science, Department of Molecular and Cellular Physiology,
and Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Jens Carlsson
- Science for Life Laboratory, Box 1031, SE-171 21 Solna, Sweden
- Department
of Biochemistry and Biophysics and Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
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15
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Zhang XC, Cao C, Zhou Y, Zhao Y. Proton transfer-mediated GPCR activation. Protein Cell 2014; 6:12-7. [PMID: 25319942 PMCID: PMC4286134 DOI: 10.1007/s13238-014-0106-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 09/28/2014] [Indexed: 12/29/2022] Open
Abstract
G-protein coupled receptors (GPCRs) play essential roles in signal transduction from the environment into the cell. While many structural features have been elucidated in great detail, a common functional mechanism on how the ligand-binding signal is converted into a conformational change on the cytoplasmic face resulting in subsequent activation of downstream effectors remain to be established. Based on available structural and functional data of the activation process in class-A GPCRs, we propose here that a change in protonation status, together with proton transfer via conserved structural elements located in the transmembrane region, are the key elements essential for signal transduction across the membrane.
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Affiliation(s)
- Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China,
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16
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Balakumar P, Jagadeesh G. Structural determinants for binding, activation, and functional selectivity of the angiotensin AT1 receptor. J Mol Endocrinol 2014; 53:R71-92. [PMID: 25013233 DOI: 10.1530/jme-14-0125] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The renin-angiotensin system (RAS) plays an important role in the pathophysiology of cardiovascular disorders. Pharmacologic interventions targeting the RAS cascade have led to the discovery of renin inhibitors, angiotensin-converting enzyme inhibitors, and AT(1) receptor blockers (ARBs) to treat hypertension and some cardiovascular and renal disorders. Mutagenesis and modeling studies have revealed that differential functional outcomes are the results of multiple active states conformed by the AT(1) receptor upon interaction with angiotensin II (Ang II). The binding of agonist is dependent on both extracellular and intramembrane regions of the receptor molecule, and as a consequence occupies more extensive area of the receptor than a non-peptide antagonist. Both agonist and antagonist bind to the same intramembrane regions to interfere with each other's binding to exhibit competitive, surmountable interaction. The nature of interactions with the amino acids in the receptor is different for each of the ARBs given the small differences in the molecular structure between drugs. AT(1) receptors attain different conformation states after binding various Ang II analogues, resulting in variable responses through activation of multiple signaling pathways. These include both classical and non-classical pathways mediated through growth factor receptor transactivations, and provide cross-communication between downstream signaling molecules. The structural requirements for AT(1) receptors to activate extracellular signal-regulated kinases 1 and 2 through G proteins, or G protein-independently through β-arrestin, are different. We review the structural and functional characteristics of Ang II and its analogs and antagonists, and their interaction with amino acid residues in the AT(1) receptor.
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Affiliation(s)
- Pitchai Balakumar
- Pharmacology UnitFaculty of Pharmacy, AIMST University, Semeling, 08100 Bedong, Kedah Darul Aman, MalaysiaDivision of Cardiovascular and Renal ProductsCenter for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993, USA
| | - Gowraganahalli Jagadeesh
- Pharmacology UnitFaculty of Pharmacy, AIMST University, Semeling, 08100 Bedong, Kedah Darul Aman, MalaysiaDivision of Cardiovascular and Renal ProductsCenter for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993, USA
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17
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Cichello SA, Weisinger RS, Schuijers J, Jois M. 1-Sarcosine-angiotensin II infusion effects on food intake, weight loss, energy expenditure, and skeletal muscle UCP3 gene expression in a rat model. J Cachexia Sarcopenia Muscle 2014; 5:239-46. [PMID: 24614996 PMCID: PMC4159489 DOI: 10.1007/s13539-014-0133-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/27/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND There are a myriad of proteins responsible for modulation of expenditure of energy. Angiotensin II (Ang II) is a vital component of renin-angiotensin system that affects blood pressure and also linked to both cachexia and obesity via fat and muscle metabolism. Previous research suggests that the direct action of Ang II is on the brain, via angiotensin II type 1 receptor protein, affecting food intake and energy expenditure. The objective of the study is to investigate the effect of 1-sarcosine (SAR)-Ang II infusion on energy expenditure and metabolism in a rat model of congestive heart failure cachexia. METHODS Adult female rats of the Sprague Dawley strain (n = 33) were used (11 pair-fed control, 12 ad libitum and 10, 1-sarcosine-angiotensin II-infused rats). Body weight, faecal excretion, feed intake (in grams), water intake (in milliliters) and urine excreted were recorded daily. The measurements were recorded in three different periods (4 days prior to surgery, "pre-infusion"; day of surgery and 5 days postsurgery, "infusion period"; days 7 to 14, "recovery" period). Different analytical methods were used to measure energy expenditure per period, uncoupling protein 3 mRNA expression, crude protein and adipose tissue body composition. RESULTS During the infusion period, the SAR-Ang II group experienced rapid weight loss (p < 0.05) in comparison to the ad libitum and pair-fed groups. The SAR-Ang II group displayed lower (p < 0.05) body fat content (in percent) than the controls. There was also increased (p < 0.05) uncoupling protein 3 (UCP3) mRNA expression in the SAR-Ang II group and pair-fed group when compared to the controls. CONCLUSION In summary, the results suggest that SAR-Ang II infusion impairs appetite and decreases body weight by wasting predominantly adipose tissue, which may be due to elevated energy expenditure via mitochondrial uncoupling (UCP3 protein activity).
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Affiliation(s)
- S A Cichello
- School of Life Sciences, La Trobe University, Bundoora, VIC, 3086, Australia,
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18
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Katritch V, Fenalti G, Abola EE, Roth BL, Cherezov V, Stevens RC. Allosteric sodium in class A GPCR signaling. Trends Biochem Sci 2014; 39:233-44. [PMID: 24767681 DOI: 10.1016/j.tibs.2014.03.002] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 01/16/2023]
Abstract
Despite their functional and structural diversity, G-protein-coupled receptors (GPCRs) share a common mechanism of signal transduction via conformational changes in the seven-transmembrane (7TM) helical domain. New major insights into this mechanism come from the recent crystallographic discoveries of a partially hydrated sodium ion that is specifically bound in the middle of the 7TM bundle of multiple class A GPCRs. This review discusses the remarkable structural conservation and distinct features of the Na(+) pocket in this most populous GPCR class, as well as the conformational collapse of the pocket upon receptor activation. New insights help to explain allosteric effects of sodium on GPCR agonist binding and activation, and sodium's role as a potential co-factor in class A GPCR function.
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Affiliation(s)
- Vsevolod Katritch
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Gustavo Fenalti
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Enrique E Abola
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Bryan L Roth
- National Institute of Mental Health Psychoactive Drug Screening Program, Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27599, USA
| | - Vadim Cherezov
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Raymond C Stevens
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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19
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Kim YC, Mungunsukh O, McCart EA, Roehrich PJ, Yee DK, Day RM. Mechanism of erythropoietin regulation by angiotensin II. Mol Pharmacol 2014; 85:898-908. [PMID: 24695083 DOI: 10.1124/mol.113.091157] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Erythropoietin (EPO) is the primary regulator of red blood cell development. Although hypoxic regulation of EPO has been extensively studied, the mechanism(s) for basal regulation of EPO are not well understood. In vivo studies in healthy human volunteers and animal models indicated that angiotensin II (Ang II) and angiotensin converting enzyme inhibitors regulated blood EPO levels. In the current study, we found that Ang II induced EPO expression in situ in murine kidney slices and in 786-O kidney cells in culture as determined by reverse transcription polymerase chain reaction. We further investigated the signaling mechanism of Ang II regulation of EPO in 786-O cells. Pharmacological inhibitors of Ang II type 1 receptor (AT1R) and extracellular signal-regulated kinase 1/2 (ERK1/2) suppressed Ang II transcriptional activation of EPO. Inhibitors of AT2R or Src homology 2 domain-containing tyrosine phosphatase had no effect. Coimmunoprecipiation experiments demonstrated that p21Ras was constitutively bound to the AT1R; this association was increased by Ang II but was reduced by the AT1R inhibitor telmisartan. Transmembrane domain (TM) 2 of AT1R is important for G protein-dependent ERK1/2 activation, and mutant D74E in TM2 blocked Ang II activation of ERK1/2. Ang II signaling induced the nuclear translocation of the Egr-1 transcription factor, and overexpression of dominant-negative Egr-1 blocked EPO promoter activation by Ang II. These data identify a novel pathway for basal regulation of EPO via AT1R-mediated Egr-1 activation by p21Ras-mitogen-activated protein kinase/ERK kinase-ERK1/2. Our current data suggest that Ang II, in addition to regulating blood volume and pressure, may be a master regulator of erythropoiesis.
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Affiliation(s)
- Yong-Chul Kim
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland (Y.-C.K., O.M., E.A.M., P.J.R., R.M.D.); and Department of Animal Biology, University of Pennsylvania, Philadelphia, Pennsylvania (D.K.Y.)
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20
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Miller-Gallacher JL, Nehmé R, Warne T, Edwards PC, Schertler GFX, Leslie AGW, Tate CG. The 2.1 Å resolution structure of cyanopindolol-bound β1-adrenoceptor identifies an intramembrane Na+ ion that stabilises the ligand-free receptor. PLoS One 2014; 9:e92727. [PMID: 24663151 PMCID: PMC3963952 DOI: 10.1371/journal.pone.0092727] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 02/25/2014] [Indexed: 12/30/2022] Open
Abstract
The β1-adrenoceptor (β1AR) is a G protein-coupled receptor (GPCR) that is activated by the endogenous agonists adrenaline and noradrenaline. We have determined the structure of an ultra-thermostable β1AR mutant bound to the weak partial agonist cyanopindolol to 2.1 Å resolution. High-quality crystals (100 μm plates) were grown in lipidic cubic phase without the assistance of a T4 lysozyme or BRIL fusion in cytoplasmic loop 3, which is commonly employed for GPCR crystallisation. An intramembrane Na+ ion was identified co-ordinated to Asp872.50, Ser1283.39 and 3 water molecules, which is part of a more extensive network of water molecules in a cavity formed between transmembrane helices 1, 2, 3, 6 and 7. Remarkably, this water network and Na+ ion is highly conserved between β1AR and the adenosine A2A receptor (rmsd of 0.3 Å), despite an overall rmsd of 2.4 Å for all Cα atoms and only 23% amino acid identity in the transmembrane regions. The affinity of agonist binding and nanobody Nb80 binding to β1AR is unaffected by Na+ ions, but the stability of the receptor is decreased by 7.5°C in the absence of Na+. Mutation of amino acid side chains that are involved in the co-ordination of either Na+ or water molecules in the network decreases the stability of β1AR by 5–10°C. The data suggest that the intramembrane Na+ and associated water network stabilise the ligand-free state of β1AR, but still permits the receptor to form the activated state which involves the collapse of the Na+ binding pocket on agonist binding.
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Affiliation(s)
| | - Rony Nehmé
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
| | - Tony Warne
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
| | - Patricia C. Edwards
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
| | - Gebhard F. X. Schertler
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
| | - Andrew G. W. Leslie
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
| | - Christopher G. Tate
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire, United Kingdom
- * E-mail:
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21
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Zhang XC, Sun K, Zhang L, Li X, Cao C. GPCR activation: protonation and membrane potential. Protein Cell 2013; 4:747-60. [PMID: 24057762 DOI: 10.1007/s13238-013-3073-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 09/11/2013] [Indexed: 12/22/2022] Open
Abstract
GPCR proteins represent the largest family of signaling membrane proteins in eukaryotic cells. Their importance to basic cell biology, human diseases, and pharmaceutical interventions is well established. Many crystal structures of GPCR proteins have been reported in both active and inactive conformations. These data indicate that agonist binding alone is not sufficient to trigger the conformational change of GPCRs necessary for binding of downstream G-proteins, yet other essential factors remain elusive. Based on analysis of available GPCR crystal structures, we identified a potential conformational switch around the conserved Asp2.50, which consistently shows distinct conformations between inactive and active states. Combining the structural information with the current literature, we propose an energy-coupling mechanism, in which the interaction between a charge change of the GPCR protein and the membrane potential of the living cell plays a key role for GPCR activation.
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Affiliation(s)
- Xuejun C Zhang
- National Laboratory of Macromolecules, National Center for Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China,
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22
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Cabana J, Holleran B, Beaulieu MÈ, Leduc R, Escher E, Guillemette G, Lavigne P. Critical hydrogen bond formation for activation of the angiotensin II type 1 receptor. J Biol Chem 2012; 288:2593-604. [PMID: 23223579 DOI: 10.1074/jbc.m112.395939] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors contain selectively important residues that play central roles in the conformational changes that occur during receptor activation. Asparagine 111 (N111(3.35)) is such a residue within the angiotensin II type 1 (AT(1)) receptor. Substitution of N111(3.35) for glycine leads to a constitutively active receptor, whereas substitution for tryptophan leads to an inactivable receptor. Here, we analyzed the AT(1) receptor and two mutants (N111G and N111W) by molecular dynamics simulations, which revealed a novel molecular switch involving the strictly conserved residue D74(2.50). Indeed, D74(2.50) forms a stable hydrogen bond (H-bond) with the residue in position 111(3.35) in the wild-type and the inactivable receptor. However, in the constitutively active mutant N111G-AT(1) receptor, residue D74 is reoriented to form a new H-bond with another strictly conserved residue, N46(1.50). When expressed in HEK293 cells, the mutant N46G-AT(1) receptor was poorly activable, although it retained a high binding affinity. Interestingly, the mutant N46G/N111G-AT(1) receptor was also inactivable. Molecular dynamics simulations also revealed the presence of a cluster of hydrophobic residues from transmembrane domains 2, 3, and 7 that appears to stabilize the inactive form of the receptor. Whereas this hydrophobic cluster and the H-bond between D74(2.50) and W111(3.35) are more stable in the inactivable N111W-AT(1) receptor, the mutant N111W/F77A-AT(1) receptor, designed to weaken the hydrophobic core, showed significant agonist-induced signaling. These results support the potential for the formation of an H-bond between residues D74(2.50) and N46(1.50) in the activation of the AT(1) receptor.
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Affiliation(s)
- Jérôme Cabana
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quecec J1H 5N4, Canada
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Zhuo JL, Li XC. New insights and perspectives on intrarenal renin-angiotensin system: focus on intracrine/intracellular angiotensin II. Peptides 2011; 32:1551-65. [PMID: 21699940 PMCID: PMC3137727 DOI: 10.1016/j.peptides.2011.05.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/05/2011] [Accepted: 05/09/2011] [Indexed: 02/06/2023]
Abstract
Although renin, the rate-limiting enzyme of the renin-angiotensin system (RAS), was first discovered by Robert Tigerstedt and Bergman more than a century ago, the research on the RAS still remains stronger than ever. The RAS, once considered to be an endocrine system, is now widely recognized as dual (circulating and local/tissue) or multiple hormonal systems (endocrine, paracrine and intracrine). In addition to the classical renin/angiotensin I-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II receptor (AT₁/AT₂) axis, the prorenin/(Pro)renin receptor (PRR)/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, and the Ang IV/AT₄/insulin-regulated aminopeptidase (IRAP) axis have recently been discovered. Furthermore, the roles of the evolving RAS have been extended far beyond blood pressure control, aldosterone synthesis, and body fluid and electrolyte homeostasis. Indeed, novel actions and underlying signaling mechanisms for each member of the RAS in physiology and diseases are continuously uncovered. However, many challenges still remain in the RAS research field despite of more than one century's research effort. It is expected that the research on the expanded RAS will continue to play a prominent role in cardiovascular, renal and hypertension research. The purpose of this article is to review the progress recently being made in the RAS research, with special emphasis on the local RAS in the kidney and the newly discovered prorenin/PRR/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, the Ang IV/AT₄/IRAP axis, and intracrine/intracellular Ang II. The improved knowledge of the expanded RAS will help us better understand how the classical renin/ACE/Ang II/AT₁ receptor axis, extracellular and/or intracellular origin, interacts with other novel RAS axes to regulate blood pressure and cardiovascular and kidney function in both physiological and diseased states.
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Affiliation(s)
- Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, the University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
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Bonde MM, Hansen JT, Sanni SJ, Haunsø S, Gammeltoft S, Lyngsø C, Hansen JL. Biased signaling of the angiotensin II type 1 receptor can be mediated through distinct mechanisms. PLoS One 2010; 5:e14135. [PMID: 21152433 PMCID: PMC2994726 DOI: 10.1371/journal.pone.0014135] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 10/29/2010] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Seven transmembrane receptors (7TMRs) can adopt different active conformations facilitating a selective activation of either G protein or β-arrestin-dependent signaling pathways. This represents an opportunity for development of novel therapeutics targeting selective biological effects of a given receptor. Several studies on pathway separation have been performed, many of these on the Angiotensin II type 1 receptor (AT1R). It has been shown that certain ligands or mutations facilitate internalization and/or recruitment of β-arrestins without activation of G proteins. However, the underlying molecular mechanisms remain largely unresolved. For instance, it is unclear whether such selective G protein-uncoupling is caused by a lack of ability to interact with G proteins or rather by an increased ability of the receptor to recruit β-arrestins. Since uncoupling of G proteins by increased ability to recruit β-arrestins could lead to different cellular or in vivo outcomes than lack of ability to interact with G proteins, it is essential to distinguish between these two mechanisms. METHODOLOGY/PRINCIPAL FINDINGS We studied five AT1R mutants previously published to display pathway separation: D74N, DRY/AAY, Y292F, N298A, and Y302F (Ballesteros-Weinstein numbering: 2.50, 3.49-3.51, 7.43, 7.49, and 7.53). We find that D74N, DRY/AAY, and N298A mutants are more prone to β-arrestin recruitment than WT. In contrast, receptor mutants Y292F and Y302F showed impaired ability to recruit β-arrestin in response to Sar1-Ile4-Ile8 (SII) Ang II, a ligand solely activating the β-arrestin pathway. CONCLUSIONS/SIGNIFICANCE Our analysis reveals that the underlying conformations induced by these AT1R mutants most likely represent principally different mechanisms of uncoupling the G protein, which for some mutants may be due to their increased ability to recruit β-arrestin2. Hereby, these findings have important implications for drug discovery and 7TMR biology and illustrate the necessity of uncovering the exact molecular determinants for G protein-coupling and β-arrestin recruitment, respectively.
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Affiliation(s)
- Marie Mi Bonde
- Laboratory for Molecular Cardiology, The Danish National Research Foundation Centre for Cardiac Arrhythmia, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Tind Hansen
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Samra Joke Sanni
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Stig Haunsø
- Laboratory for Molecular Cardiology, The Danish National Research Foundation Centre for Cardiac Arrhythmia, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Steen Gammeltoft
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Christina Lyngsø
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Jakob Lerche Hansen
- Laboratory for Molecular Cardiology, The Danish National Research Foundation Centre for Cardiac Arrhythmia, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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Evans AN, Henning T, Gelsleichter J, Nunez BS. Molecular classification of an elasmobranch angiotensin receptor: quantification of angiotensin receptor and natriuretic peptide receptor mRNAs in saltwater and freshwater populations of the Atlantic stingray. Comp Biochem Physiol B Biochem Mol Biol 2010; 157:423-31. [PMID: 20869458 DOI: 10.1016/j.cbpb.2010.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/14/2010] [Accepted: 09/16/2010] [Indexed: 10/19/2022]
Abstract
Among the most conserved osmoregulatory hormone systems in vertebrates are the renin-angiotensin system (RAS) and the natriuretic peptides (NPs). We examined the RAS and NP system in the euryhaline Atlantic stingray, Dasyatis sabina (Lesueur). To determine the relative sensitivity of target organs to these hormonal systems, we isolated cDNA sequences encoding the D. sabina angiotensin receptor (AT) and natriuretic peptide type-B receptor (NPR-B). We then determined the tissue-specific expression of their mRNAs in saltwater D. sabina from local Texas waters and an isolated freshwater population in Lake Monroe, Florida. AT mRNA was most abundant in interrenal tissue from both populations. NPR-B mRNA was most abundant in rectal gland tissue from both populations, and also highly abundant in the kidney of saltwater D. sabina. This study is the first to report the sequence of an elasmobranch angiotensin receptor, and phylogenetic analysis indicates that the D. sabina receptor is more similar to AT(1) vs. AT(2) proteins. This classification is further supported by molecular analysis of AT(1) and AT(2) proteins demonstrating conservation of AT(1)-specific amino acid residues and motifs in D. sabina AT. Molecular classification of the elasmobranch angiotensin receptor as an AT(1)-like protein provides fundamental insight into the evolution of the vertebrate RAS.
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Affiliation(s)
- Andrew N Evans
- The University of Texas Marine Science Institute, Port Aransas, Texas 78373, USA.
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de Noronha SMR, Corrêa SAA, Poletti EF, Lopes DD, da Silva CC, Sforça ML, Shimuta SI, Zanchin NIT, Nakaie CR, da Silva IDCG. Structural analysis of three peptides related to the transmambranic helix VI of AT1 receptor. Neuropeptides 2010; 44:115-8. [PMID: 20006383 DOI: 10.1016/j.npep.2009.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 11/11/2009] [Accepted: 11/12/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Angiotensin II (AII) is the main active product of the renin angiotensin system. Better known effects of AII are via AT1 receptor (AT1R). Expression of AT1R mutants (L265D and L262D) in CHO cells increased cAMP formation when compared to CHO cells expressing the wild type (WT) AT1R. Morphological transformation of CHO cells transfected with mutants correlated with their increased cAMP formation. DNA synthesis was inhibited in these cells too, indicating that cAMP promotes inhibitory effects on transfected CHO cells growth and causes their morphological change from a tumorigenic phenotype to a non-tumorigenic one. OBJECTIVES To assess the importance of leucine 262 and 265 in determining AT1R structure by means of a comparative structural analysis of two mutant peptides and of a wild-type fragment. METHODOLOGY Three peptides had their conformation compared by circular dichroism (CD): L262D(259-272), L265D(259-272) (mutants) and WT(260-277). RESULTS Secondary structures were: beta-turn for WT and L262D and random coil for L265D. CONCLUSIONS Strong correlation was found in the results of biochemical, cellular and structural approaches used to compare WT AT1R to mutant types. Random coil structure of the L265D mutant may be a key point to explain those changes observed in biochemical (binding and signal transduction) and proliferation assays (Correa et al., 2005). beta-Turn formation is an important step during early protein folding and this secondary simple structure is present in L262D and WT, but not in L265D. Therefore, leucine 265 seems to play a crucial role in determining an entirely functional AT1R.
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Affiliation(s)
- Samuel Marcos Ribeiro de Noronha
- Ginecologia Molecular/Ginecologia, UNIFESP-R. Pedro de Toledo, 791 - 4o. Andar, V. Clementino, CEP04039032 Sao Paulo, SP, Brazil.
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A conserved protonation-induced switch can trigger "ionic-lock" formation in adrenergic receptors. J Mol Biol 2010; 397:1339-49. [PMID: 20132827 DOI: 10.1016/j.jmb.2010.01.060] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/19/2010] [Accepted: 01/25/2010] [Indexed: 11/23/2022]
Abstract
The mechanism of signal transduction in G-protein-coupled receptors (GPCRs) is a crucial step in cell signaling. However, the molecular details of this process are still largely undetermined. Carrying out submicrosecond molecular dynamics simulations of beta-adrenergic receptors, we found that cooperation between a number of highly conserved residues is crucial to alter the equilibrium between the active state and the inactive state of diffusible ligand GPCRs. In particular, "ionic-lock" formation in beta-adrenergic receptors is directly correlated with the protonation state of a highly conserved aspartic acid residue [Asp(2.50)] even though the two sites are located more than 20 A away from each other. Internal polar residues, acting as local microswitches, cooperate to propagate the signal from Asp(2.50) to the G-protein interaction site at the helix III-helix VI interface. Evolutionarily conserved differences between opsin and non-opsin GPCRs in the surrounding of Asp(2.50) influence the acidity of this residue and can thus help in rationalizing the differences in constitutive activity of class A GPCRs.
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Bhuiyan MA, Hossain M, Ishiguro M, Nakamura T, Nagatomo T. Engineered Mutation of Some Important Amino Acids in Angiotensin II Type 1 (AT1) Receptor Increases the Binding Affinity of AT1-Receptor Antagonists. J Pharmacol Sci 2010; 113:57-65. [DOI: 10.1254/jphs.09361fp] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Vanni S, Neri M, Tavernelli I, Rothlisberger U. Observation of "ionic lock" formation in molecular dynamics simulations of wild-type beta 1 and beta 2 adrenergic receptors. Biochemistry 2009; 48:4789-97. [PMID: 19378975 DOI: 10.1021/bi900299f] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
G protein coupled receptors (GPCRs) are a large family of integral membrane proteins involved in signal transduction pathways, making them appealing drug targets for a wide spectrum of diseases. The recently crystallized structures of two engineered adrenergic receptors have opened new avenues for the understanding of the molecular mechanisms of action of GPCRs. Taking the two crystal structures as a starting point, we carried out submicrosecond molecular dynamics simulations of wild-type beta(1) and beta(2) adrenergic receptors in a lipid bilayer under physiological conditions. These simulations give access to structural and dynamic properties of the receptors in pseudo in vivo conditions. For both systems the overall fold properties of the transmembrane region as well as the binding pocket remain close to the crystal structure of the engineered systems, thus suggesting that the ligand binding mode is not affected by the introduced modifications. Both simulations indicate the presence of one or two internal water molecules absent in both crystal structures and essential for the stabilization of the binding pocket at the interface between transmembrane helices III, IV, and V. The different interactions arising from the substitution of Tyr308 in beta(2)AR into Phe325 in beta(1)AR induce different conformations of the homologous Asn(6.55) inside the binding pockets of the two receptors, suggesting a possible origin of receptor specificity in agonist binding. The equilibrated structures of both receptors recover all of the previously suggested features of inactive GPCRs including formation of a salt bridge between the cytoplasmatic moieties of helices III and VI ("ionic lock") that is absent in the crystal structures.
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Affiliation(s)
- Stefano Vanni
- Laboratory of Computational Chemistry and Biochemistry, Federal Institute of Technology, EPFL, CH-1015 Lausanne, Switzerland
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31
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Aplin M, Bonde MM, Hansen JL. Molecular determinants of angiotensin II type 1 receptor functional selectivity. J Mol Cell Cardiol 2009; 46:15-24. [DOI: 10.1016/j.yjmcc.2008.09.123] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 09/09/2008] [Accepted: 09/18/2008] [Indexed: 01/14/2023]
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Proulx CD, Holleran BJ, Boucard AA, Escher E, Guillemette G, Leduc R. Mutational analysis of the conserved Asp2.50 and ERY motif reveals signaling bias of the urotensin II receptor. Mol Pharmacol 2008; 74:552-61. [PMID: 18509066 DOI: 10.1124/mol.108.045054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Class A (rhodopsin-like) G protein-coupled receptors possess conserved residues and motifs that are important for their specific activity. In the present study, we examined the role of residue Asp97(2.50) as well as residues Glu147(3.49), Arg148(3.50), and Tyr149(3.51) of the ERY motif on the functionality of the urotensin II receptor (UT). Mutations D97(2.50)A, R148(3.50)A, and R148(3.50)H abolished the ability of UT to activate phospholipase C, whereas mutations E147(3.49)A and Y149(3.51)A reduced the ability to activate PLC by 50%. None of the mutants exhibited constitutive activity. However, R148(3.50)A and R148(3.50)H promoted ERK1/2 activation, which was abolished by 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478), an inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase activity. Both these mutants were capable of directly activating EGFR, which confirmed that they activated the mitogen-activated protein kinase (MAPK) pathway by a Galpha(q/11)-independent transactivation of EGFR. The D97(2.50)A, R148(3.50)A, and R148(3.50)H mutants did not readily internalize and did not promote translocation or colocalize with beta-arrestin2-GFP. Finally, the agonist-induced internalization of the E147(3.49)A mutant receptor was significantly increased compared with wild-type receptor. This study highlights the major contribution of the conserved Asp(2.50) residue to the functionality of the UT receptor. The Arg residue in the ERY motif of UT is an important structural element in signaling crossroads that determine whether Galpha(q/11)-dependent and -independent events can occur.
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Affiliation(s)
- Christophe D Proulx
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4 ON, Canada
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Proulx CD, Holleran BJ, Lavigne P, Escher E, Guillemette G, Leduc R. Biological properties and functional determinants of the urotensin II receptor. Peptides 2008; 29:691-9. [PMID: 18155322 DOI: 10.1016/j.peptides.2007.10.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 10/12/2007] [Accepted: 10/19/2007] [Indexed: 02/07/2023]
Abstract
The urotensin II receptor (UT) is a member of the G protein-coupled receptor (GPCR) family and binds the cyclic undecapeptide urotensin II (U-II) as well as the octapeptide urotensin II-related peptide (URP). The active UT mediates pleiotropic effects through various signal transduction pathways, including coupling to G proteins and activating the mitogen-activated protein kinase pathway. Several highly conserved residues and motifs of class A GPCRs that are important for activity are found in UT. This review highlights some of the putative roles of these motifs in the binding, activation and desensitization of UT.
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Affiliation(s)
- Christophe D Proulx
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec, J1H 5N4 Canada
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Billet S, Bardin S, Verp S, Baudrie V, Michaud A, Conchon S, Muffat-Joly M, Escoubet B, Souil E, Hamard G, Bernstein KE, Gasc JM, Elghozi JL, Corvol P, Clauser E. Gain-of-function mutant of angiotensin II receptor, type 1A, causes hypertension and cardiovascular fibrosis in mice. J Clin Invest 2007; 117:1914-25. [PMID: 17607364 PMCID: PMC1890996 DOI: 10.1172/jci28764] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 04/24/2007] [Indexed: 01/06/2023] Open
Abstract
The role of the renin-angiotensin system has been investigated by overexpression or inactivation of its different genes in animals. However, there is no data concerning the effect of the constitutive activation of any component of the system. A knockin mouse model has been constructed with a gain-of-function mutant of the Ang II receptor, type 1A (AT(1A)), associating a constitutively activating mutation (N111S) with a C-terminal deletion, which impairs receptor internalization and desensitization. In vivo consequences of this mutant receptor expression in homozygous mice recapitulate its in vitro characteristics: the pressor response is more sensitive to Ang II and longer lasting. These mice present with a moderate (~20 mmHg) and stable increase in BP. They also develop early and progressive renal fibrosis and cardiac fibrosis and diastolic dysfunction. However, there was no overt cardiac hypertrophy. The hormonal parameters (low-renin and inappropriately normal aldosterone productions) mimic those of low-renin human hypertension. This new model reveals that a constitutive activation of AT(1A) leads to cardiac and renal fibrosis in spite of a modest effect on BP and will be useful for investigating the role of Ang II in target organs in a model similar to some forms of human hypertension.
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Affiliation(s)
- Sandrine Billet
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sabine Bardin
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sonia Verp
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Véronique Baudrie
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Annie Michaud
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sophie Conchon
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Martine Muffat-Joly
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Brigitte Escoubet
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Evelyne Souil
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ghislaine Hamard
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Kenneth E. Bernstein
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jean Marie Gasc
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jean-Luc Elghozi
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Pierre Corvol
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Eric Clauser
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, INSERM U567, Paris, France.
Faculté de Médecine Paris Descartes, INSERM U652, Université Paris Descartes, Paris, France.
INSERM U36, Collège de France, Paris, France.
INSERM IFR02, Centre d’Explorations Fonctionnelles Intégrées, Université Denis Diderot, Paris, France.
INSERM U772, Collège de France, Assistance Publique Hôpitaux de Paris, Hôpital Bichat–Claude Bernard, Paris, France.
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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35
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Karnik SS, Husain A, Graham RM. Proceedings of the Symposium ‘Angiotensin AT1 Receptors: From Molecular Physiology to Therapeutics’: MOLECULAR DETERMINANTS OF PEPTIDE AND NON-PEPTIDE BINDING TO THE AT1 RECEPTOR. Clin Exp Pharmacol Physiol 2007; 23 Suppl 3:S58-66. [DOI: 10.1111/j.1440-1681.1996.tb02815.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Thomas WG, Thekkumkara TJ, Baker KM. Proceedings of the Symposium ‘Angiotensin AT1 Receptors: From Molecular Physiology to Therapeutics’: MOLECULAR MECHANISMS OF ANGIOTENSIN II (AT1a) RECEPTOR ENDOCYTOSIS. Clin Exp Pharmacol Physiol 2007; 23 Suppl 3:S74-80. [DOI: 10.1111/j.1440-1681.1996.tb02817.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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37
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Oliveira L, Costa-Neto CM, Nakaie CR, Schreier S, Shimuta SI, Paiva ACM. The Angiotensin II AT1 Receptor Structure-Activity Correlations in the Light of Rhodopsin Structure. Physiol Rev 2007; 87:565-92. [PMID: 17429042 DOI: 10.1152/physrev.00040.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The most prevalent physiological effects of ANG II, the main product of the renin-angiotensin system, are mediated by the AT1 receptor, a rhodopsin-like AGPCR. Numerous studies of the cardiovascular effects of synthetic peptide analogs allowed a detailed mapping of ANG II's structural requirements for receptor binding and activation, which were complemented by site-directed mutagenesis studies on the AT1 receptor to investigate the role of its structure in ligand binding, signal transduction, phosphorylation, binding to arrestins, internalization, desensitization, tachyphylaxis, and other properties. The knowledge of the high-resolution structure of rhodopsin allowed homology modeling of the AT1 receptor. The models thus built and mutagenesis data indicate that physiological (agonist binding) or constitutive (mutated receptor) activation may involve different degrees of expansion of the receptor's central cavity. Residues in ANG II structure seem to control these conformational changes and to dictate the type of cytosolic event elicited during the activation. 1) Agonist aromatic residues (Phe8 and Tyr4) favor the coupling to G protein, and 2) absence of these residues can favor a mechanism leading directly to receptor internalization via phosphorylation by specific kinases of the receptor's COOH-terminal Ser and Thr residues, arrestin binding, and clathrin-dependent coated-pit vesicles. On the other hand, the NH2-terminal residues of the agonists ANG II and [Sar1]-ANG II were found to bind by two distinct modes to the AT1 receptor extracellular site flanked by the COOH-terminal segments of the EC-3 loop and the NH2-terminal domain. Since the [Sar1]-ligand is the most potent molecule to trigger tachyphylaxis in AT1 receptors, it was suggested that its corresponding binding mode might be associated with this special condition of receptors.
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Affiliation(s)
- Laerte Oliveira
- Department of Biophysics, Escola Paulista de Medicina, Federal University of São Paulo, Brazil.
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38
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Nikiforovich GV, Zhang M, Yang Q, Jagadeesh G, Chen HC, Hunyady L, Marshall GR, Catt KJ. Interactions between Conserved Residues in Transmembrane Helices 2 and 7 during Angiotensin AT1Receptor Activation. Chem Biol Drug Des 2006; 68:239-49. [PMID: 17177883 DOI: 10.1111/j.1747-0285.2006.00444.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Site-directed mutagenesis studies and independent molecular modeling studies were combined to investigate the network of inter-residue interactions within the transmembrane region of the angiotensin AT(1a) receptor. Site-directed mutagenesis was focused on residues Tyr292, Asn294, Asn295, and Asn298 in transmembrane helix 7, and the conserved Asp74 in helix 2 and other polar residues. Functional interactions between pairs of residues were evaluated by determining the effects of single and double-reciprocal mutations on agonist-induced AT(1a) receptor activation. Replacement of Tyr292 by aspartate in helix 7 abolished radioligand binding to both Y292D and D74Y/Y292D mutant receptors. Reciprocal mutations of Asp74/Asn294, Ser115/Asn294, Ser252/Asn294, and Asn298/Sen115 caused additive impairment of function, suggesting that these pairs of residues make independent contributions to AT(1a) receptor activation. In contrast, mutations of the Asp74/Tyr298 pair revealed that the D74N/N298D reciprocal mutation substantially increased the impaired inositol phosphate responses of the D74N and N298D receptors. Extensive molecular modeling yielded 3D models of the TM region of the AT(1) receptor and the mutants as well as of their complexes with angiotensin II, which were used to rationalize the possible reasons of impairing of function of some mutants. These data indicate that Asp74 and Asn298 are not optimally positioned for direct strong interaction in the resting conformation of the AT(1a) receptor. Balance of interactions between residues in helix 2 (as D74) and helix 7 (as N294, N295 and N298) in the AT(1) receptors, however, has a crucial role both in determining their functional activity and levels of their expression.
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Affiliation(s)
- Gregory V Nikiforovich
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St Louis, MO 63110, USA.
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39
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Miotto B, Struhl K. Differential gene regulation by selective association of transcriptional coactivators and bZIP DNA-binding domains. Mol Cell Biol 2006; 26:5969-82. [PMID: 16880509 PMCID: PMC1592802 DOI: 10.1128/mcb.00696-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
bZIP DNA-binding domains are targets for viral and cellular proteins that function as transcriptional coactivators. Here, we show that MBF1 and the related Chameau and HBO1 histone acetylases interact with distinct subgroups of bZIP proteins, whereas pX does not discriminate. Selectivity of Chameau and MBF1 for bZIP proteins is mediated by residues in the basic region that lie on the opposite surface from residues that contact DNA. Chameau functions as a specific coactivator for the AP-1 class of bZIP proteins via two arginine residues. A conserved glutamic acid/glutamine in the linker region underlies MBF1 specificity for a subgroup of bZIP factors. Chameau and MBF1 cannot synergistically coactivate transcription due to competitive interactions with the basic region, but either protein can synergistically coactivate with pX. Analysis of Jun derivatives that selectively interact with these coactivators reveals that MBF1 is crucial for the response to oxidative stress, whereas Chameau is important for the response to chemical and osmotic stress. Thus, the bZIP domain mediates selective interactions with coactivators and hence differential regulation of gene expression.
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Affiliation(s)
- Benoit Miotto
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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40
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Yee DK, Suzuki A, Luo L, Fluharty SJ. Identification of Structural Determinants for G Protein-Independent Activation of Mitogen-Activated Protein Kinases in the Seventh Transmembrane Domain of the Angiotensin II Type 1 Receptor. Mol Endocrinol 2006; 20:1924-34. [PMID: 16556732 DOI: 10.1210/me.2006-0018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Although the intrareceptor mechanisms whereby the angiotensin II (AngII) type 1 receptor activates phospholipase C (PLC) have been extensively investigated, analogous studies of signaling through mitogen-activated protein kinases (MAPK) have been lacking. We investigated MAPK activation and traditional G(q)/PLC signaling in transfected cells using AngII and the signaling selective agonist [Sar(1),Ile(4),Ile(8)] AngII (SII). SII stimulated MAPK without inositol trisphosphate (IP(3)) production and thereby stabilizes an activated receptor state linked to G protein-independent MAPK signaling. Using receptor mutagenesis, we focused on the seventh transmembrane domain and identified three key residues-Tyr(292), Phe(293), and Thr(287). At least three distinct activated states were revealed: 1) an AngII-stabilized state linked to G(q)/PLC signaling, 2) an AngII-stabilized state connected to G protein-independent MAPK activation, and 3) a SII-stabilized state associated with G protein-independent MAPK signaling. The mutant Y292F failed to exhibit AngII-induced IP(3) turnover yet remained capable of AngII-induced MAPK activation. SII failed to stimulate MAPK in Y292F-transfected cells. Thus, Tyr(292) is a key epitope for activated states 1 and 3 but not required for activated state 2. Although the F293L mutant retained normal AngII responses, it also showed an IP(3) response to SII, indicating that Phe(293) may be involved in constraining the receptor to its inactive state. Mutations of Thr(287) abolished all SII-induced signaling without affecting any AngII responses. Thr(287) therefore represents a key residue for a SII-stabilized activated state. Taken together, the data identified a novel structural requirement (Thr(287)) for the SII-stabilized activated state and redefined the mechanistic roles for Tyr(292) and Phe(293).
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MESH Headings
- Animals
- COS Cells
- Chlorocebus aethiops
- Conserved Sequence
- Enzyme Activation/physiology
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Extracellular Signal-Regulated MAP Kinases/physiology
- GTP-Binding Proteins/metabolism
- GTP-Binding Proteins/physiology
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Models, Biological
- Mutation
- Point Mutation
- Protein Structure, Quaternary
- Protein Structure, Tertiary
- Rats
- Receptor, Angiotensin, Type 1/agonists
- Receptor, Angiotensin, Type 1/chemistry
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Transfection
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Affiliation(s)
- Daniel K Yee
- Department of Animal Biology, University of Pennsylvania, Philadelphia, 19104-6046, USA.
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41
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Baleanu-Gogonea C, Karnik S. Model of the whole rat AT1 receptor and the ligand-binding site. J Mol Model 2006; 12:325-37. [PMID: 16404618 DOI: 10.1007/s00894-005-0049-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 07/22/2005] [Indexed: 10/25/2022]
Abstract
We present a three-dimensional model of the rat type 1 receptor (AT1) for the hormone angiotensin II (Ang II). Ang II and the AT1 receptor play a critical role in the cell-signaling process responsible for the actions of renin-angiotensin system in the regulation of blood pressure, water-electrolyte homeostasis and cell growth. Development of improved therapeutics would be significantly enhanced with the availability of a 3D-structure model for the AT1 receptor and of the binding site for agonists and antagonists. This model was constructed using a combination of computation and homology-modeling techniques starting with the experimentally determined three-dimensional structure of bovine rhodopsin (PDB#1F88) as a template. All 359 residues and two disulfide bonds in the rat AT1 receptor have been accounted for in this model. Ramachandran-map analysis and a 1 nanosecond molecular dynamics simulation of the solvated receptor with and without the bound ligand, Ang II, lend credence to the validity of the model. Docking calculations were performed with the agonist, Ang II and the antihypertensive antagonist, losartan. [Figure: see text].
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Affiliation(s)
- Camelia Baleanu-Gogonea
- Department of Molecular Cardiology at Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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42
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Nikiforovich GV, Mihalik B, Catt KJ, Marshall GR. Molecular mechanisms of constitutive activity: mutations at position 111 of the angiotensin AT1 receptor. ACTA ACUST UNITED AC 2005; 66:236-48. [PMID: 16218991 DOI: 10.1111/j.1399-3011.2005.00293.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A possible molecular mechanism for the constitutive activity of mutants of the angiotensin type 1 receptor (AT1) at position 111 was suggested by molecular modeling. This involves a cascade of conformational changes in spatial positions of side chains along transmembrane helix (TM3) from L112 to Y113 to F117, which in turn, results in conformational changes in TM4 (residues I152 and M155) leading to the movement of TM4 as a whole. The mechanism is consistent with the available data of site-directed mutagenesis, as well as with correct predictions of constitutive activity of mutants L112F and L112C. It was also predicted that the double mutant N111G/L112A might possess basal constitutive activity comparable with that of the N111G mutant, whereas the double mutants N111G/Y113A, N111G/F117A, and N111G/I152A would have lower levels of basal activity. Experimental studies of the above double mutants showed significant constitutive activity of N111G/L112A and N111G/F117A. The basal activity of N111G/I152A was higher than expected, and that of N111G/Y113A was not determined due to poor expression of the mutant. The proposed mechanism of constitutive activity of the AT(1) receptor reveals a novel nonsimplistic view on the general problem of constitutive activity, and clearly demonstrates the inherent complexity of the process of G protein-coupled receptor (GPCR) activation.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- CHO Cells
- Cricetinae
- Intracellular Membranes/metabolism
- Ligands
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed/methods
- Mutation
- Protein Binding
- Protein Conformation
- Protein Structure, Tertiary/genetics
- Rats
- Receptor, Angiotensin, Type 1/chemistry
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Transfection
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Affiliation(s)
- G V Nikiforovich
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO 63110, USA.
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43
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Volpe M, Trimarco B. A Novel Molecule of the Angiotensin II Receptor Blocker Class. High Blood Press Cardiovasc Prev 2005. [DOI: 10.2165/00151642-200512020-00004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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44
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Li B, Nowak NM, Kim SK, Jacobson KA, Bagheri A, Schmidt C, Wess J. Random mutagenesis of the M3 muscarinic acetylcholine receptor expressed in yeast: identification of second-site mutations that restore function to a coupling-deficient mutant M3 receptor. J Biol Chem 2004; 280:5664-75. [PMID: 15572356 DOI: 10.1074/jbc.m411623200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The M(3) muscarinic receptor is a prototypical member of the class A family of G protein-coupled receptors (GPCRs). To gain insight into the structural mechanisms governing agonist-mediated M(3) receptor activation, we recently developed a genetically modified yeast strain (Saccharomyces cerevisiae) which allows the efficient screening of large libraries of mutant M(3) receptors to identify mutant receptors with altered/novel functional properties. Class A GPCRs contain a highly conserved Asp residue located in transmembrane domain II (TM II; corresponding to Asp-113 in the rat M(3) muscarinic receptor) which is of fundamental importance for receptor activation. As observed previously with other GPCRs analyzed in mammalian expression systems, the D113N point mutation abolished agonist-induced receptor/G protein coupling in yeast. We then subjected the D113N mutant M(3) receptor to PCR-based random mutagenesis followed by a yeast genetic screen to recover point mutations that can restore G protein coupling to the D113N mutant receptor. A large scale screening effort led to the identification of three such second-site suppressor mutations, R165W, R165M, and Y250D. When expressed in the wild-type receptor background, these three point mutations did not lead to an increase in basal activity and reduced the efficiency of receptor/G protein coupling. Similar results were obtained when the various mutant receptors were expressed and analyzed in transfected mammalian cells (COS-7 cells). Interestingly, like Asp-113, Arg-165 and Tyr-250, which are located at the cytoplasmic ends of TM III and TM V, respectively, are also highly conserved among class A GPCRs. Our data suggest a conformational link between the highly conserved Asp-113, Arg-165, and Tyr-250 residues which is critical for receptor activation.
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Affiliation(s)
- Bo Li
- Department of Molecular Signaling, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 8 Center Dr., Bethesda, MD 20892, USA
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45
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Kristiansen K. Molecular mechanisms of ligand binding, signaling, and regulation within the superfamily of G-protein-coupled receptors: molecular modeling and mutagenesis approaches to receptor structure and function. Pharmacol Ther 2004; 103:21-80. [PMID: 15251227 DOI: 10.1016/j.pharmthera.2004.05.002] [Citation(s) in RCA: 394] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The superfamily of G-protein-coupled receptors (GPCRs) could be subclassified into 7 families (A, B, large N-terminal family B-7 transmembrane helix, C, Frizzled/Smoothened, taste 2, and vomeronasal 1 receptors) among mammalian species. Cloning and functional studies of GPCRs have revealed that the superfamily of GPCRs comprises receptors for chemically diverse native ligands including (1) endogenous compounds like amines, peptides, and Wnt proteins (i.e., secreted proteins activating Frizzled receptors); (2) endogenous cell surface adhesion molecules; and (3) photons and exogenous compounds like odorants. The combined use of site-directed mutagenesis and molecular modeling approaches have provided detailed insight into molecular mechanisms of ligand binding, receptor folding, receptor activation, G-protein coupling, and regulation of GPCRs. The vast majority of family A, B, C, vomeronasal 1, and taste 2 receptors are able to transduce signals into cells through G-protein coupling. However, G-protein-independent signaling mechanisms have also been reported for many GPCRs. Specific interaction motifs in the intracellular parts of these receptors allow them to interact with scaffold proteins. Protein engineering techniques have provided information on molecular mechanisms of GPCR-accessory protein, GPCR-GPCR, and GPCR-scaffold protein interactions. Site-directed mutagenesis and molecular dynamics simulations have revealed that the inactive state conformations are stabilized by specific interhelical and intrahelical salt bridge interactions and hydrophobic-type interactions. Constitutively activating mutations or agonist binding disrupts such constraining interactions leading to receptor conformations that associates with and activate G-proteins.
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Affiliation(s)
- Kurt Kristiansen
- Department of Pharmacology, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
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46
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Pulakat L, Mandavia CH, Gavini N. Role of Phe308 in the seventh transmembrane domain of the AT2 receptor in ligand binding and signaling. Biochem Biophys Res Commun 2004; 319:1138-43. [PMID: 15194486 DOI: 10.1016/j.bbrc.2004.05.092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Indexed: 11/28/2022]
Abstract
Studies on Angiotensin II (Ang II) receptor type AT1 have suggested that interaction between the two highly conserved residues, Tyr292 in the 7th transmembrane domain (TMD) and the Asp74 in the 2nd TMD, is critical for linking the Ang II binding and AT1 receptor-Gq protein coupling. In the Ang II receptor type AT2, the Asp is conserved (Asp90 in 2nd TMD), however, there is no Tyr residue in the 7th TMD and Phe308 occupies the analogous position to Tyr292 of the AT1. Replacing this Phe308 with Ala reduced receptor affinity to peptidic ligands (125)I-Ang II (K(d) = 0.37 nM) and (125)I-CGP42112A (K(d) = 0.56 nM), but retained the ability of the AT2 to reduce cGMP levels in Xenopus oocytes. Thus, the Phe308 of the AT2 does not mimic the role of Tyr292 of the AT1 in the receptor activation upon Ang II binding. We have also shown that the M8 mutant of the AT2 with the 7th TMD similar to that of wild type AT2 can couple to PLC like the AT1 and bind the AT2-specific ligands with high affinity. Since the Ang II is shown to bind to both the AT1 and the AT2 in an identical manner, we propose that the absence of Tyr in the 7th TMD of the AT2 does not prevent the receptor from coupling to Gq-protein, rather may contribute to the freedom of the AT2 to couple to trimeric G-proteins in both G- betagamma dependent and independent manners upon Ang II binding.
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Affiliation(s)
- Lakshmi Pulakat
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
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47
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Abstract
GnRH and its analogs are used extensively for the treatment of hormone-dependent diseases and assisted reproductive techniques. They also have potential as novel contraceptives in men and women. A thorough delineation of the molecular mechanisms involved in ligand binding, receptor activation, and intracellular signal transduction is kernel to understanding disease processes and the development of specific interventions. Twenty-three structural variants of GnRH have been identified in protochordates and vertebrates. In many vertebrates, three GnRHs and three cognate receptors have been identified with distinct distributions and functions. In man, the hypothalamic GnRH regulates gonadotropin secretion through the pituitary GnRH type I receptor via activation of G(q). In-depth studies have identified amino acid residues in both the ligand and receptor involved in binding, receptor activation, and translation into intracellular signal transduction. Although the predominant coupling of the type I GnRH receptor in the gonadotrope is through productive G(q) stimulation, signal transduction can occur via other G proteins and potentially by G protein-independent means. The eventual selection of intracellular signaling may be specifically directed by variations in ligand structure. A second form of GnRH, GnRH II, conserved in all higher vertebrates, including man, is present in extrahypothalamic brain and many reproductive tissues. Its cognate receptor has been cloned from various vertebrate species, including New and Old World primates. The human gene homolog of this receptor, however, has a frame-shift and stop codon, and it appears that GnRH II signaling occurs through the type I GnRH receptor. There has been considerable plasticity in the use of different GnRHs, receptors, and signaling pathways for diverse functions. Delineation of the structural elements in GnRH and the receptor, which facilitate differential signaling, will contribute to the development of novel interventive GnRH analogs.
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Affiliation(s)
- Robert P Millar
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, Scotland, United Kingdom.
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48
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Volpe M, Musumeci B, De Paolis P, Savoia C, Morganti A. Angiotensin II AT2 receptor subtype: an uprising frontier in cardiovascular disease? J Hypertens 2003; 21:1429-43. [PMID: 12872031 DOI: 10.1097/00004872-200308000-00001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The renin-angiotensin system (RAS) plays a pivotal role in the regulation of fluid, electrolyte balance and blood pressure, and is a modulator of cellular growth and proliferation. Biological actions of RAS are linked to the binding of the effector molecule, angiotensin II (AngII), to specific membrane receptors, mostly the AT1 subtype and, to a lesser extent, other subtypes. Following the identification and characterization of the AT2 subtype receptor, it has been proposed that a complex interaction between AngII and its receptors may play an important role in the effects of RAS. In this paper current information on AngII subtype receptors--their structure, regulation and intracellular signalling--are reviewed, with a particular emphasis on the potential relevance for cardiovascular pathophysiology. In addition, we discuss modulation of expression of the AT2 receptor and its interaction with the AT1 receptor subtype, as well as the potential effects of this receptor on blood pressure regulation. A better understanding of the integrated effects of the AngII subtype receptors may help to elucidate the function of the RAS, as well as their participation in the mechanisms of cardiovascular disease and attendant therapeutic implications.
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Affiliation(s)
- Massimo Volpe
- Cattedra di Cardiologia, II Facoltà di Medicina, Dipartimento di Medicina Sperimentale e Patologia, Università La Sapienza, Rome, Italy.
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Hines J, Fluharty SJ, Yee DK. Structural determinants for the activation mechanism of the angiotensin II type 1 receptor differ for phosphoinositide hydrolysis and mitogen-activated protein kinase pathways. Biochem Pharmacol 2003; 66:251-62. [PMID: 12826267 DOI: 10.1016/s0006-2952(03)00257-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While the mechanism whereby the angiotensin II type 1 receptor (AT(1) receptor) activates its classical effector phospholipase C-beta (PLC-beta) has largely been elucidated, there is little consensus on how this receptor activates a more recently identified effector, the p42/44 mitogen-activated protein kinases (p42/44(MAPK)). Using transfected COS-1 cells, we investigated the activation of this signaling pathway at the receptor level itself. Previous mutational studies that relied on phosphoinositide turnover as an index of receptor activation have indicated that key residues in the second and seventh transmembrane domains participate in AT(1) receptor activation mechanisms. Thus, we introduced a variety of mutations-AT(1)[D74N], AT(1)[Y292F], AT(1)[N295S], and AT(1)[AT(2) TM7], which is composed of a chimeric substitution of the AT(1) seventh transmembrane domain with its AT(2) counterpart. These mutations that strongly diminished the receptor's ability to activate PLC-beta had little to no effect on its ability to activate p42/44(MAPK), which not only suggests that p42/44(MAPK) does not exclusively lie downstream of the G-protein G(q)/PLC-beta pathway but also indicates that more than one activation state may exist for the AT(1) receptor. The failure of a protein kinase C inhibitor to block AT(1) receptor activation of p42/44(MAPK) further corroborated evidence that the receptor's activation of p42/44(MAPK) is largely independent of the G(q)/PLC-beta/PKC pathway. Taken together, the experimental evidence strongly suggests that the mechanism whereby the AT(1) receptor activates p42/44(MAPK) is fundamentally different from that for PLC-beta, even at the level of the receptor itself.
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Affiliation(s)
- John Hines
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104-6046, USA
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Dugourd C, Gervais M, Corvol P, Monnot C. Akt is a major downstream target of PI3-kinase involved in angiotensin II-induced proliferation. Hypertension 2003; 41:882-90. [PMID: 12623864 DOI: 10.1161/01.hyp.0000060821.62417.35] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Different signal transduction cascades have been implicated in angiotensin II (Ang II)-mediated cell growth, such as the extracellular signal-regulated kinase 1/2 (ERK1/2) and the phosphatidylinositol 3-kinase (PI3K) pathways. To identify the downstream targets of PI3K involved in Ang II-induced proliferation, we used both rat aortic smooth muscle (RASM) cells and a CHO cell line stably expressing the rat AT1A receptor. The ERK1/2 and PI3K pathways are independently activated and implicated in Ang II-mediated DNA synthesis and cell number increase in these 2 cell lines. In addition, a specific inhibitor of Akt inhibited Ang II-induced Akt phosphorylation, DNA synthesis and proliferation in CHO-AT1A or RASM cells. A dominant-negative mutant of Akt was also found to selectively block Ang II-induced proliferation of CHO-AT1A cells. To further elucidate the signaling events leading to Akt activation, we used an AT1 receptor mutant (AT1AD74E), deficient for Gq protein coupling, and the intracellular calcium chelator BAPTA-AM. Although altered Akt and ERK1/2 activation was observed in the CHO-AT1AD74E cell line, blockade of intracellular calcium elevation did not affect phosphorylation of these kinases. These results provide the first evidence of a specific and necessary role of Akt in Ang II-induced proliferation through a Gq protein-dependent calcium-independent pathway.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- CHO Cells
- Calcium Signaling
- Cell Division
- Cricetinae
- MAP Kinase Signaling System
- Male
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Mutation
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphorylation
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-akt
- Rats
- Receptor, Angiotensin, Type 1
- Receptors, Angiotensin/genetics
- Receptors, Angiotensin/metabolism
- Recombinant Proteins/metabolism
- Signal Transduction
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Affiliation(s)
- Céline Dugourd
- INSERM U36-Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France
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