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Singh KD, Karnik SS. Structural perspectives on the mechanism of signal activation, ligand selectivity and allosteric modulation in angiotensin receptors: IUPHAR Review 34. Br J Pharmacol 2022; 179:4461-4472. [PMID: 35318654 PMCID: PMC9398925 DOI: 10.1111/bph.15840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
Functional advances have guided our knowledge of physiological and fatal pathological mechanisms of the hormone angiotensin II (AngII) and its antagonists. Such studies revealed that tissue response to a given dose of the hormone or its antagonist depends on receptors that engage the ligand. Thus, we need to know much more about the structures of receptor-ligand complexes at high resolution. Recently, X-ray structures of both AngII receptors (AT1 and AT2 receptors) bound to peptide and non-peptide ligands have been elucidated, providing new opportunities to examine the dynamic fluxes in the 3D architecture of the receptors, as the basis of ligand selectivity, efficacy, and regulation of the molecular functions of the receptors. Constituent structural motifs cooperatively transform ligand selectivity into specific functions, thus conceptualizing the primacy of the 3D structure over individual motifs of receptors. This review covers the new data elucidating the structural dynamics of AngII receptors and how structural knowledge can be transformative in understanding the mechanisms underlying the physiology of AngII.
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Affiliation(s)
- Khuraijam Dhanachandra Singh
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Sadashiva S. Karnik
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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2
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Yang FF, Zhou JZ, Xu XL, Hu T, Liu JQ, Wu YX, Wei B, Ma LY. Discovery of 1,3,4-oxadiazole derivatives containing a bisamide moiety as a novel class of potential cardioprotective agents. Eur J Med Chem 2022; 239:114526. [PMID: 35716515 DOI: 10.1016/j.ejmech.2022.114526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022]
Abstract
Myocardial injury is a nonnegligible problem in cardiovascular diseases and cancer therapy. The functional feature of N-containing heterocycles in the cardiovascular field has attracted much attention in recent years. Herein, we discovered a lead compound 12a containing 1,3,4-oxadiazole by extensive screening of anticancer derivatives containing nitrogen-heterocycle, which exhibited potential protective activity against oxidative stress in cardiomyocytes. Follow-up structure-activity relationship (SAR) studies also highlighted the role of substitution sites and bisamide moiety in enhancing the protective activity against oxidative stress. Specifically, compound 12d exhibited low cytotoxicity under high concentration and potent myocardial protection against oxidative stress in H9c2 cells. Preliminary mechanistic studies showed compound 12d could decrease the expression of cardiac hypertrophy and oxidative stress-related proteins/genes and reduce mitochondria-mediated cell apoptosis, thereby enhancing the cell vitality of injured cardiomyocytes. In this study, 1,3,4-oxadiazole may represent a novel pharmacophore that possesses potential myocardial protection and provides more choices for future optimization of cardiovascular drugs, especially for the treatment of onco-cardiology.
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Affiliation(s)
- Fei-Fei Yang
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Jin-Zhu Zhou
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Xue-Li Xu
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Ting Hu
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Jian-Quan Liu
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Ya-Xi Wu
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Bo Wei
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China.
| | - Li-Ying Ma
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, School of Pharmaceutical Science and Institute of Pharmaceutical Science, Zhengzhou University, Zhengzhou, Henan, 450001, PR China; China Meheco Topfond Pharmaceutical Co., Zhumadian, 463000, PR China.
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3
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Receptors | Angiotensin Receptors. ENCYCLOPEDIA OF BIOLOGICAL CHEMISTRY III 2021. [PMCID: PMC8326513 DOI: 10.1016/b978-0-12-819460-7.00096-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The renin-angiotensin-aldosterone system (RAS) is a vital hormone-receptor system that regulates cardiovascular and renal functions. In this article, we discuss exciting new findings in the RAS field. Recently solved active state crystal structures of Angiotensin II type 1 (AT1R) and type 2 receptor (AT2R) helped in understanding receptor activation mechanisms in detail. Also, considerable attention is given to the developments in characterizing the counter-regulatory RAS axis due to current hope for harnessing this axis for the development of protective therapies against various cardiovascular diseases. We describe the RAS component, angiotensin-converting enzyme 2 (ACE2) functioning as cellular entry receptor for the causative agent of COVID-19 pandemic, SARS-CoV-2. Altogether, these discoveries paved the way for developing novel therapies targeting different components of the RAS in the future.
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4
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Insights into the Interaction of LVV-Hemorphin-7 with Angiotensin II Type 1 Receptor. Int J Mol Sci 2020; 22:ijms22010209. [PMID: 33379211 PMCID: PMC7795518 DOI: 10.3390/ijms22010209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/17/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022] Open
Abstract
Hemorphins are known for their role in the control of blood pressure. Recently, we revealed the positive modulation of the angiotensin II (AngII) type 1 receptor (AT1R) by LVV-hemorphin-7 (LVV-H7) in human embryonic kidney (HEK293) cells. Here, we examined the molecular binding behavior of LVV-H7 on AT1R and its effect on AngII binding using a nanoluciferase-based bioluminescence resonance energy transfer (NanoBRET) assay in HEK293FT cells, as well as molecular docking and molecular dynamics (MD) studies. Saturation and real-time kinetics supported the positive effect of LVV-H7 on the binding of AngII. While the competitive antagonist olmesartan competed with AngII binding, LVV-H7 slightly, but significantly, decreased AngII’s kD by 2.6 fold with no effect on its Bmax. Molecular docking and MD simulations indicated that the binding of LVV-H7 in the intracellular region of AT1R allosterically potentiates AngII binding. LVV-H7 targets residues on intracellular loops 2 and 3 of AT1R, which are known binding sites of allosteric modulators in other GPCRs. Our data demonstrate the allosteric effect of LVV-H7 on AngII binding, which is consistent with the positive modulation of AT1R activity and signaling previously reported. This further supports the pharmacological targeting of AT1R by hemorphins, with implications in vascular and renal physiology.
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5
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Li X, Liao J, Jiang Z, Liu X, Chen S, He X, Zhu L, Duan X, Xu Z, Qi B, Guo X, Tong R, Shi J. A concise review of recent advances in anti-heart failure targets and its small molecules inhibitors in recent years. Eur J Med Chem 2020; 186:111852. [PMID: 31759729 DOI: 10.1016/j.ejmech.2019.111852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/03/2019] [Accepted: 11/04/2019] [Indexed: 11/30/2022]
Abstract
Heart failure is a disease with high mortality and the risk of heart failure increases in magnitude with age. The patients of heart failure is increasing year by year. Hence, Pharmaceutical researchers have to develop new drugs with better pharmacological effects to coping with this phenomenon. In this article, we reviewed the small molecule compounds for heart failure that have been marketed in recent years or are promising to enter clinical research. We also reviewed the SAR (structure activity relationship) of these molecules, such as renin inhibitors, ROMK inhibitors, a kind of new diuretics, and some dual-targets inhibitors. These small molecules proven to be beneficial effect on heart failure patients. Which may provide ideas for the design of novel anti-heart failure therapeutic drugs.
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Affiliation(s)
- Xingxing Li
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China
| | - Jing Liao
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China; Pediatric Department Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, People's Republic of China, Chengdu, 610072, China
| | - Zhongliang Jiang
- Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Xinyu Liu
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China
| | - Shan Chen
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China
| | - Xia He
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China; Department of Pharmacy, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Individual Key Laboratory, Chengdu, People's Republic of China, Chengdu, 610072, China
| | - Ling Zhu
- Eastern Hospital, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, 610072, China
| | - Xingmei Duan
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China; Department of Pharmacy, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Individual Key Laboratory, Chengdu, People's Republic of China, Chengdu, 610072, China
| | - Zhuyu Xu
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China
| | - Baowen Qi
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Xiaoqiang Guo
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Rongsheng Tong
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China; Department of Pharmacy, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Individual Key Laboratory, Chengdu, People's Republic of China, Chengdu, 610072, China.
| | - Jianyou Shi
- School of Medicine, University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, 610054, China; Department of Pharmacy, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Individual Key Laboratory, Chengdu, People's Republic of China, Chengdu, 610072, China.
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6
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Erol I, Cosut B, Durdagi S. Toward Understanding the Impact of Dimerization Interfaces in Angiotensin II Type 1 Receptor. J Chem Inf Model 2019; 59:4314-4327. [PMID: 31429557 DOI: 10.1021/acs.jcim.9b00294] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Angiotensin II type 1 receptor (AT1R) is a prototypical class A G protein-coupled receptor (GPCR) that has an important role in cardiovascular pathologies and blood pressure regulation as well as in the central nervous system. GPCRs may exist and function as monomers; however, they can assemble to form higher order structures, and as a result of oligomerization, their function and signaling profiles can be altered. In the case of AT1R, the classical Gαq/11 pathway is initiated with endogenous agonist angiotensin II binding. A variety of cardiovascular pathologies such as heart failure, diabetic nephropathy, atherosclerosis, and hypertension are associated with this pathway. Recent findings reveal that AT1R can form homodimers and activate the noncanonical (β-arrestin-mediated) pathway. Nevertheless, the exact dimerization interface and atomic details of AT1R homodimerization have not been still elucidated. Here, six different symmetrical dimer interfaces of AT1R are considered, and homodimers were constructed using other published GPCR crystal dimer interfaces as template structures. These AT1R homodimers were then inserted into the model membrane bilayers and subjected to all-atom molecular dynamics simulations. Our simulation results along with the principal component analysis and water pathway analysis suggest four different interfaces as the most plausible: symmetrical transmembrane (TM)1,2,8; TM5; TM4; and TM4,5 AT1R dimer interfaces that consist of one inactive and one active protomer. Moreover, we identified ILE2386.33 as a hub residue in the stabilization of the inactive state of AT1R.
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Affiliation(s)
- Ismail Erol
- Department of Chemistry , Gebze Technical University , Gebze 41400 , Kocaeli , Turkey
| | - Bunyemin Cosut
- Department of Chemistry , Gebze Technical University , Gebze 41400 , Kocaeli , Turkey
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7
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Wingler LM, McMahon C, Staus DP, Lefkowitz RJ, Kruse AC. Distinctive Activation Mechanism for Angiotensin Receptor Revealed by a Synthetic Nanobody. Cell 2019; 176:479-490.e12. [PMID: 30639100 DOI: 10.1016/j.cell.2018.12.006] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 09/16/2018] [Accepted: 12/04/2018] [Indexed: 01/14/2023]
Abstract
The angiotensin II (AngII) type 1 receptor (AT1R) is a critical regulator of cardiovascular and renal function and is an important model for studies of G-protein-coupled receptor (GPCR) signaling. By stabilizing the receptor with a single-domain antibody fragment ("nanobody") discovered using a synthetic yeast-displayed library, we determined the crystal structure of active-state human AT1R bound to an AngII analog with partial agonist activity. The nanobody binds to the receptor's intracellular transducer pocket, stabilizing the large conformational changes characteristic of activated GPCRs. The peptide engages the AT1R through an extensive interface spanning from the receptor core to its extracellular face and N terminus, remodeling the ligand-binding cavity. Remarkably, the mechanism used to propagate conformational changes through the receptor diverges from other GPCRs at several key sites, highlighting the diversity of allosteric mechanisms among GPCRs. Our structure provides insight into how AngII and its analogs stimulate full or biased signaling, respectively.
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Affiliation(s)
- Laura M Wingler
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Conor McMahon
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Dean P Staus
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Robert J Lefkowitz
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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8
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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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9
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Fillion D, Cabana J, Guillemette G, Leduc R, Lavigne P, Escher E. Structure of the human angiotensin II type 1 (AT1) receptor bound to angiotensin II from multiple chemoselective photoprobe contacts reveals a unique peptide binding mode. J Biol Chem 2013; 288:8187-8197. [PMID: 23386604 DOI: 10.1074/jbc.m112.442053] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs.
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Affiliation(s)
- Dany Fillion
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Jérôme Cabana
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Gaétan Guillemette
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Richard Leduc
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Pierre Lavigne
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Emanuel Escher
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada.
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10
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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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11
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Wheatley M, Wootten D, Conner MT, Simms J, Kendrick R, Logan RT, Poyner DR, Barwell J. Lifting the lid on GPCRs: the role of extracellular loops. Br J Pharmacol 2012; 165:1688-1703. [PMID: 21864311 DOI: 10.1111/j.1476-5381.2011.01629.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
GPCRs exhibit a common architecture of seven transmembrane helices (TMs) linked by intracellular loops and extracellular loops (ECLs). Given their peripheral location to the site of G-protein interaction, it might be assumed that ECL segments merely link the important TMs within the helical bundle of the receptor. However, compelling evidence has emerged in recent years revealing a critical role for ECLs in many fundamental aspects of GPCR function, which supported by recent GPCR crystal structures has provided mechanistic insights. This review will present current understanding of the key roles of ECLs in ligand binding, activation and regulation of both family A and family B GPCRs.
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Affiliation(s)
- M Wheatley
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - D Wootten
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - M T Conner
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - J Simms
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - R Kendrick
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - R T Logan
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - D R Poyner
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - J Barwell
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
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12
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Benned-Jensen T, Mokrosinski J, Rosenkilde MM. The E92K melanocortin 1 receptor mutant induces cAMP production and arrestin recruitment but not ERK activity indicating biased constitutive signaling. PLoS One 2011; 6:e24644. [PMID: 21931793 PMCID: PMC3172247 DOI: 10.1371/journal.pone.0024644] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 08/17/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The melanocortin 1 receptor (MC1R) constitutes a key regulator of melanism. Consequently, many naturally-occurring MC1R mutations are associated with a change in color. An example is the Glu-to-Lys substitution found at position II:20/2.60 in the top of transmembrane helix II which has been identified in melanic mice and several other species. This mutation induces a pronounced increase in MC1R constitutive activity suggesting a link between constitutive activity and melanism which is corroborated by the attenuation of α-melanocyte stimulating hormone (αMSH) induced activation. However, the mechanism by which the mutation induces constitutive activity is currently not known. METHODOLOGY/PRINCIPAL FINDINGS Here we characterize the constitutive activity, cell surface expression and internalization of the mouse mutant, Mc1r E92K. As previously reported, only positively charged residues at position II:20/2.60 induced an increase in constitutive activity as measured by cAMP accumulation and CREB activation. Furthermore, the mutation induced a constitutive recruitment of β-arrestin. This phenomenon is only observed in MC1R, however, as the equivalent mutations in MC2-5R had no effect on receptor signaling. Interestingly, the mutation did not induce constitutive ERK1/2 phosphorylation or increase the internalization rate indicating the constitutive activity to be biased. Finally, to identify regions of importance for the increased constitutive activity of Mc1r E92K, we employed a chimeric approach and identified G102 and L110 in the extracellular loop 1 to be selectively important for the constitutive activity as this, but not αMSH-mediated activation, was abolished upon Ala substitution. CONCLUSIONS/SIGNIFICANCE It is concluded that the E92K mutation induces an active conformation distinct from that induced by αMSH and that the extracellular loop 1 is involved in maintaining this conformational state. In turn, the results suggest that in MC1R, which lacks an extracellular loop 2, the first extracellular loop may play a more prominent role during receptor activation than in general.
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Affiliation(s)
- Tau Benned-Jensen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacek Mokrosinski
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M. Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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Coin I, Perrin MH, Vale WW, Wang L. Photo-cross-linkers incorporated into G-protein-coupled receptors in mammalian cells: a ligand comparison. Angew Chem Int Ed Engl 2011; 50:8077-81. [PMID: 21751313 DOI: 10.1002/anie.201102646] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Indexed: 01/07/2023]
Abstract
Capturing the right ligand at the right spot: a well-balanced system for non-natural amino acid mutagenesis allows the ligand binding sites of a class II G-protein coupled receptor to be mapped and distinct binding domains to be identified for different ligands in the native environment of mammalian cells.
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Affiliation(s)
- Irene Coin
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Coin I, Perrin MH, Vale WW, Wang L. Photo-Cross-Linkers Incorporated into G-Protein-Coupled Receptors in Mammalian Cells: A Ligand Comparison. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201102646] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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