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Qin G, Xu J, Liang Y, Fang X. Single-Molecule Imaging Reveals Differential AT1R Stoichiometry Change in Biased Signaling. Int J Mol Sci 2023; 25:374. [PMID: 38203545 PMCID: PMC10778740 DOI: 10.3390/ijms25010374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/10/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024] Open
Abstract
G protein-coupled receptors (GPCRs) represent promising therapeutic targets due to their involvement in numerous physiological processes mediated by downstream G protein- and β-arrestin-mediated signal transduction cascades. Although the precise control of GPCR signaling pathways is therapeutically valuable, the molecular details for governing biased GPCR signaling remain elusive. The Angiotensin II type 1 receptor (AT1R), a prototypical class A GPCR with profound implications for cardiovascular functions, has become a focal point for biased ligand-based clinical interventions. Herein, we used single-molecule live-cell imaging techniques to evaluate the changes in stoichiometry and dynamics of AT1R with distinct biased ligand stimulations in real time. It was revealed that AT1R existed predominantly in monomers and dimers and underwent oligomerization upon ligand stimulation. Notably, β-arrestin-biased ligands induced the formation of higher-order aggregates, resulting in a slower diffusion profile for AT1R compared to G protein-biased ligands. Furthermore, we demonstrated that the augmented aggregation of AT1R, triggered by activation from each biased ligand, was completely abrogated in β-arrestin knockout cells. These findings furnish novel insights into the intricate relationship between GPCR aggregation states and biased signaling, underscoring the pivotal role of molecular behaviors in guiding the development of selective therapeutic agents.
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Affiliation(s)
- Gege Qin
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiachao Xu
- Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuxin Liang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohong Fang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou 310022, China
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2
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Zhang X, Zhang S, Wang M, Chen H, Liu H. Advances in the allostery of angiotensin II type 1 receptor. Cell Biosci 2023; 13:110. [PMID: 37330563 DOI: 10.1186/s13578-023-01063-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/31/2023] [Indexed: 06/19/2023] Open
Abstract
Angiotensin II type 1 receptor (AT1R) is a promising therapeutic target for cardiovascular diseases. Compared with orthosteric ligands, allosteric modulators attract considerable attention for drug development due to their unique advantages of high selectivity and safety. However, no allosteric modulators of AT1R have been applied in clinical trials up to now. Except for the classical allosteric modulators of AT1R such as antibody, peptides and amino acids, cholesterol and biased allosteric modulators, there are non-classical allosteric modes including the ligand-independent allosteric mode, and allosteric mode of biased agonists and dimers. In addition, finding the allosteric pockets based on AT1R conformational change and interaction interface of dimers are the future of drug design. In this review, we summarize the different allosteric mode of AT1R, with a view to contribute to the development and utilization of drugs targeting AT1R allostery.
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Affiliation(s)
- Xi Zhang
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, People's Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China
| | - Suli Zhang
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, People's Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China
| | - Meili Wang
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, People's Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China
| | - Hao Chen
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, People's Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China
| | - Huirong Liu
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, People's Republic of China.
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China.
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 10 Xitoutiao, You An Men Street, Beijing, 100069, China.
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3
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The transmembrane domains of GPCR dimers as targets for drug development. Drug Discov Today 2023; 28:103419. [PMID: 36309194 DOI: 10.1016/j.drudis.2022.103419] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/06/2022] [Accepted: 10/20/2022] [Indexed: 02/02/2023]
Abstract
G-protein-coupled receptors (GPCRs) can form homodimers or heterodimers that modulate specific signal transduction pathways to regulate a wide range of physiological and pathological functions. As such, GPCR dimers are novel drug targets for disorders including depression, hypertension, diabetes, and vascular dementia. The interaction between two receptors in a GPCR dimer involves a conformational change in the transmembrane domain (TMD). It has been demonstrated that the TMD has an important role in GPCR dimer formation and stability in vitro and in vivo. Moreover, increasing evidence shows that the TMD of GPCRs affects the function of dimers. Therefore, the TMD of GPCRs is an emerging target for the development of drugs to treat diseases that involve GPCR dimerization.
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4
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Gallo M, Defaus S, Andreu D. Disrupting GPCR Complexes with Smart Drug-like Peptides. Pharmaceutics 2022; 14:pharmaceutics14010161. [PMID: 35057055 PMCID: PMC8779866 DOI: 10.3390/pharmaceutics14010161] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are a superfamily of proteins classically described as monomeric transmembrane (TM) receptors. However, increasing evidence indicates that many GPCRs form higher-order assemblies made up of monomers pertaining to identical (homo) or to various (hetero) receptors. The formation and structure of these oligomers, their physiological role and possible therapeutic applications raise a variety of issues that are currently being actively explored. In this context, synthetic peptides derived from TM domains stand out as powerful tools that can be predictably targeted to disrupt GPCR oligomers, especially at the interface level, eventually impairing their action. However, despite such potential, TM-derived, GPCR-disrupting peptides often suffer from inadequate pharmacokinetic properties, such as low bioavailability, a short half-life or rapid clearance, which put into question their therapeutic relevance and promise. In this review, we provide a comprehensive overview of GPCR complexes, with an emphasis on current studies using GPCR-disrupting peptides mimicking TM domains involved in multimerization, and we also highlight recent strategies used to achieve drug-like versions of such TM peptide candidates for therapeutic application.
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Affiliation(s)
| | - Sira Defaus
- Correspondence: (S.D.); (D.A.); Tel.: +34-933160868 (S.D. & D.A.)
| | - David Andreu
- Correspondence: (S.D.); (D.A.); Tel.: +34-933160868 (S.D. & D.A.)
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5
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Wolf P, Mohr A, Gavins G, Behr V, Mörl K, Seitz O, Beck-Sickinger AG. Orthogonal Peptide-Templated Labeling Elucidates Lateral ET A R/ET B R Proximity and Reveals Altered Downstream Signaling. Chembiochem 2021; 23:e202100340. [PMID: 34699123 PMCID: PMC9298254 DOI: 10.1002/cbic.202100340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/03/2021] [Indexed: 12/21/2022]
Abstract
Fine‐tuning of G protein‐coupled receptor (GPCR) signaling is important to maintain cellular homeostasis. Recent studies demonstrated that lateral GPCR interactions in the cell membrane can impact signaling profiles. Here, we report on a one‐step labeling method of multiple membrane‐embedded GPCRs. Based on short peptide tags, complementary probes transfer the cargo (e. g. a fluorescent dye) by an acyl transfer reaction with high spatial and temporal resolution within 5 min. We applied this approach to four receptors of the cardiovascular system: the endothelin receptor A and B (ETAR and ETBR), angiotensin II receptor type 1, and apelin. Wild type‐like G protein activation after N‐terminal modification was demonstrated for all receptor species. Using FRET‐competent dyes, a constitutive proximity between hetero‐receptors was limited to ETAR/ETBR. Further, we demonstrate, that ETAR expression regulates the signaling of co‐expressed ETBR. Our orthogonal peptide‐templated labeling of different GPCRs provides novel insight into the regulation of GPCR signaling.
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Affiliation(s)
- Philipp Wolf
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Alexander Mohr
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Georgina Gavins
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Victoria Behr
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Karin Mörl
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Oliver Seitz
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Annette G Beck-Sickinger
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
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6
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Zamel IA, Palakkott A, Ashraf A, Iratni R, Ayoub MA. Interplay Between Angiotensin II Type 1 Receptor and Thrombin Receptor Revealed by Bioluminescence Resonance Energy Transfer Assay. Front Pharmacol 2020; 11:1283. [PMID: 32973514 PMCID: PMC7468457 DOI: 10.3389/fphar.2020.01283] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 08/03/2020] [Indexed: 12/22/2022] Open
Abstract
The key hormone of the renin-angiotensin system (RAS), angiotensin II (AngII), and thrombin are known to play major roles in the vascular system and its related disorders. Previous studies reported connections between AngII and thrombin in both physiological and pathophysiological models. However, the molecular mechanisms controlling such interplay at the level of their receptors belonging to the family of G protein-coupled receptors (GPCRs) are not fully understood. In this study, we investigated the functional interaction between the AngII type 1 receptor (AT1R) and the thrombin receptor [or protease-activated receptor 1 (PAR1)] in human embryonic kidney 293 (HEK293) cells. For this, we used various bioluminescence resonance energy transfer (BRET) proximity-based assays to profile the coupling to the heterotrimeric Gαq protein, β-arrestin recruitment, and receptor internalization and trafficking in intact cells. The overall dose-response and real-time kinetic BRET data demonstrated the specific molecular proximity between AT1R and PAR1 resulting in their functional interaction. This was characterized by thrombin inducing BRET increase within AT1R/Gαq and AT1R/β-arrestin pairs and synergistic effects observed upon the concomitant activation of both receptors suggesting a positive allosteric interaction. The BRET data corroborated with the data on the downstream Gαq/inositol phosphate pathway. Moreover, the selective pharmacological blockade of the receptors revealed the implication of both AT1R and PAR1 protomers in such a synergistic interaction and the possible transactivation of AT1R by PAR1. Interestingly, the positive action of PAR1 on AT1R activation was contrasted with its apparent inhibition of AT1R internalization and its endosomal trafficking. Finally, BRET saturation and co-immunoprecipitation assays supported the physical AT1-PAR1 interaction in HEK293 cells. Our study reveals for the first time the functional interaction between AT1R and PAR1 in vitro characterized by a transactivation and positive allosteric modulation of AT1R and inhibition of its desensitization and internalization. This finding may constitute the molecular basis of the well-known interplay between RAS and thrombin. Thus, our data should lead to revising some findings on the implication of RAS and thrombin in vascular physiology and pathophysiology revealing the importance to consider the functional and pharmacological interaction between AT1R and thrombin receptors.
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Affiliation(s)
- Isra Al Zamel
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Abdulrasheed Palakkott
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Arshida Ashraf
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Rabah Iratni
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
| | - Mohammed Akli Ayoub
- Department of Biology, College of Science, The United Arab Emirates University (UAEU), Al Ain, United Arab Emirates
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7
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Transmembrane peptide 4 and 5 of APJ are essential for its heterodimerization with OX1R. Biochem Biophys Res Commun 2020; 521:408-413. [DOI: 10.1016/j.bbrc.2019.10.146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/21/2019] [Indexed: 11/17/2022]
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8
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Angiotensin II inhibits DDAH1-nNOS signaling via AT1R and μOR dimerization to modulate blood pressure control in the central nervous system. Clin Sci (Lond) 2019; 133:2401-2413. [PMID: 31755934 DOI: 10.1042/cs20191005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/21/2019] [Accepted: 11/22/2019] [Indexed: 12/31/2022]
Abstract
G protein-coupled receptors (GPCRs) are important drug targets. Blocking angiotensin II (Ang II) type 1 receptor signaling alleviates hypertension and improves outcomes in patients with heart failure. Changes in structure and trafficking of GPCR, and desensitization of GPCR signaling induce pathophysiological processes. We investigated whether Ang II, via induction of AT1R and μ-opioid receptor (μOR) dimerization in the nucleus tractus solitarius (NTS), leads to progressive hypertension. Ang II signaling increased μOR and adrenergic receptor α2A (α2A-AR) heterodimer levels and decreased expression of extracellular signal-regulated kinases 1/2T202/Y204, ribosomal protein S6 kinaseT359/S363, and nNOSS1416 phosphorylation. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) expression was abolished in the NTS of adult spontaneously hypertensive rats (SHRs). Endomorphin-2 was overexpressed in NTS of adult SHRs compared with that in 6-week-old Wistar-Kyoto rats (WKY). Administration of μOR agonist into the NTS of WKY increased blood pressure (BP), decreased nitric oxide (NO) production, and decreased DDAH1 activity. μOR agonist significantly reduced the activity of DDAH1 and decreased neuronal NO synthase (nNOS) phosphorylation. The AT1R II inhibitor, losartan, significantly decreased BP and abolished AT1R-induced formation of AT1R and μOR, and α2A-AR and μOR, heterodimers. Losartan also significantly increased the levels of nNOSS1416 phosphorylation and DDAH1 expression. These results show that Ang II may induce expression of endomorphin-2 and abolished DDAH1 activity by enhancing the formation of AT1R and μOR heterodimers in the NTS, leading to progressive hypertension.
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9
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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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10
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. Receptor-Receptor Interactions as a Widespread Phenomenon: Novel Targets for Drug Development? Front Endocrinol (Lausanne) 2019; 10:53. [PMID: 30833931 PMCID: PMC6387912 DOI: 10.3389/fendo.2019.00053] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
The discovery of receptor-receptor interactions (RRI) has expanded our understanding of the role that G protein-coupled receptors (GPCRs) play in intercellular communication. The finding that GPCRs can operate as receptor complexes, and not only as monomers, suggests that several different incoming signals could already be integrated at the plasma membrane level via direct allosteric interactions between the protomers that form the complex. Most research in this field has focused on neuronal populations and has led to the identification of a large number of RRI. However, RRI have been seen to occur not only in neurons but also in astrocytes and, outside the central nervous system, in cells of the cardiovascular and endocrine systems and in cancer cells. Furthermore, RRI involving the formation of macromolecular complexes are not limited to GPCRs, being also observed in other families of receptors. Thus, RRI appear as a widespread phenomenon and oligomerization as a common mechanism for receptor function and regulation. The discovery of these macromolecular assemblies may well have a major impact on pharmacology. Indeed, the formation of receptor complexes significantly broadens the spectrum of mechanisms available to receptors for recognition and signaling, which may be implemented through modulation of the binding sites of the adjacent protomers and of their signal transduction features. In this context, the possible appearance of novel allosteric sites in the receptor complex structure may be of particular relevance. Thus, the existence of RRI offers the possibility of new therapeutic approaches, and novel pharmacological strategies for disease treatment have already been proposed. Several challenges, however, remain. These include the accurate characterization of the role that the receptor complexes identified so far play in pathological conditions and the development of ligands specific to given receptor complexes, in order to efficiently exploit the pharmacological properties of these complexes.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, University of Padova, Padova, Italy
- *Correspondence: Diego Guidolin
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | | | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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11
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GPCR homo-oligomerization. Curr Opin Cell Biol 2018; 57:40-47. [PMID: 30453145 PMCID: PMC7083226 DOI: 10.1016/j.ceb.2018.10.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are an extensive class of trans-plasma membrane proteins that function to regulate a wide range of physiological functions. Despite a general perception that GPCRs exist as monomers an extensive literature has examined whether GPCRs can also form dimers and even higher-order oligomers, and if such organization influences various aspects of GPCR function, including cellular trafficking, ligand binding, G protein coupling and signalling. Here we focus on recent studies that employ approaches ranging from computational methods to single molecule tracking and both quantal brightness and fluorescence fluctuation measurements to assess the organization, stability and potential functional significance of dimers and oligomers within the class A, rhodopsin-like GPCR family.
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12
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No answer to the lack of specificity: mouse monoclonal antibody targeting the angiotensin II type 1 receptor AT 1 fails to recognize its target. Naunyn Schmiedebergs Arch Pharmacol 2018; 391:883-889. [PMID: 29868927 DOI: 10.1007/s00210-018-1522-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/12/2022]
Abstract
Numerous antibodies targeting G protein-coupled receptors (GPCRs) have been described as non-specific among the polyclonal antibodies against angiotensin II type 1 receptor (AT1). We have tested the newly developed AT1 receptor mouse monoclonal antibody for its specificity. Human embryonic kidney (HEK293) cells, which do not endogenously express AT1 receptor, were transfected in order to overexpress a fluorescently labeled enhanced green fluorescent protein (EGFP)-tagged human AT1 receptor. Western blot and immunofluorescence assays were performed to test the specificity of the Santa Cruz monoclonal antibody sc-57036. These results were compared to the ones obtained with the polyclonal sc-1173 anti-AT1 receptor antibodies that have already been described as non-specific. While the positive controls using GFP antibodies detected the EGFP-tagged AT1 receptor, both polyclonal and monoclonal anti-AT1 receptor antibodies failed to specifically recognize the corresponding band by Western blot, as similar bands were revealed in either transfected or non-transfected cells. It also failed to detect AT1 receptor in immunofluorescence experiments. The lack of target recognition of the monoclonal AT1 receptor antibody in our experimental conditions suggests that this antibody could give misleading results such as misidentification of the protein. To our knowledge, no specific antibodies targeting AT1 receptors have been developed so far and the field is thus in need of new technical developments.
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13
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Durdagi S, Erol I, Salmas RE, Aksoydan B, Kantarcioglu I. Oligomerization and cooperativity in GPCRs from the perspective of the angiotensin AT1 and dopamine D2 receptors. Neurosci Lett 2018; 700:30-37. [PMID: 29684528 DOI: 10.1016/j.neulet.2018.04.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/22/2022]
Abstract
G Protein-Coupled Receptors (GPCRs) can form homo- and heterodimers or constitute higher oligomeric clusters with other heptahelical GPCRs. In this article, multiscale molecular modeling approaches as well as experimental techniques which are used to study oligomerization of GPCRs are reviewed. In particular, the effect of dimerization/oligomerization to the ligand binding affinity of individual protomers and also on the efficacy of the oligomer are discussed by including diverse examples from the literature. In addition, possible allosteric effects that may emerge upon interaction of GPCRs with membrane components, like cholesterol, is also discussed. Investigation of these above-mentioned interactions may greatly contribute to the candidate molecule screening studies and development of novel therapeutics with fewer adverse effects.
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Affiliation(s)
- Serdar Durdagi
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Neuroscience Program, Graduate School of Health Sciences, Bahcesehir University, Istanbul, Turkey.
| | - Ismail Erol
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Department of Chemistry, Gebze Technical University, Kocaeli, Turkey
| | - Ramin Ekhteiari Salmas
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey
| | - Busecan Aksoydan
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Neuroscience Program, Graduate School of Health Sciences, Bahcesehir University, Istanbul, Turkey
| | - Isik Kantarcioglu
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Bioengineering Program, Graduate School of Natural and Applied Sciences, Bahcesehir University, Istanbul, Turkey
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14
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Tóth AD, Turu G, Hunyady L, Balla A. Novel mechanisms of G-protein-coupled receptors functions: AT 1 angiotensin receptor acts as a signaling hub and focal point of receptor cross-talk. Best Pract Res Clin Endocrinol Metab 2018; 32:69-82. [PMID: 29678287 DOI: 10.1016/j.beem.2018.02.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AT1 angiotensin receptor (AT1R), a prototypical G protein-coupled receptor (GPCR), is the main receptor, which mediates the effects of the renin-angiotensin system (RAS). AT1R plays a crucial role in the regulation of blood pressure and salt-water homeostasis, and in the development of pathological conditions, such as hypertension, heart failure, cardiovascular remodeling, renal fibrosis, inflammation, and metabolic disorders. Stimulation of AT1R leads to pleiotropic signal transduction pathways generating arrays of complex cellular responses. Growing amount of evidence shows that AT1R is a versatile GPCR, which has multiple unique faces with distinct conformations and signaling properties providing new opportunities for functionally selective pharmacological targeting of the receptor. Biased ligands of AT1R have been developed to selectively activate the β-arrestin pathway, which may have therapeutic benefits compared to the conventional angiotensin converting enzyme inhibitors and angiotensin receptor blockers. In this review, we provide a summary about the most recent findings and novel aspects of the AT1R function, signaling, regulation, dimerization or oligomerization and its cross-talk with other receptors, including epidermal growth factor (EGF) receptor, adrenergic receptors and CB1 cannabinoid receptor. Better understanding of the mechanisms and structural aspects of AT1R activation and cross-talk can lead to the development of novel type of drugs for the treatment of cardiovascular and other diseases.
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Affiliation(s)
- András D Tóth
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor Turu
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.
| | - András Balla
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
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Sun JC, Liu B, Zhang RW, Jiao PL, Tan X, Wang YK, Wang WZ. Overexpression of ß-Arrestin1 in the Rostral Ventrolateral Medulla Downregulates Angiotensin Receptor and Lowers Blood Pressure in Hypertension. Front Physiol 2018; 9:297. [PMID: 29643817 PMCID: PMC5882868 DOI: 10.3389/fphys.2018.00297] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/13/2018] [Indexed: 12/25/2022] Open
Abstract
Background: Hypertension is characterized by sympathetic overactivity, which is associated with an enhancement in angiotensin receptor type I (AT1R) in the rostral ventrolateral medulla (RVLM). β-arrestin1, a canonical scaffold protein, has been suggested to show a negative effect on G protein-coupled receptors via its internalization and desensitization and/or the biased signaling pathway. The major objectives of the present study were to observe the effect of β-arrestin1 overexpression in the RVLM on cardiovascular regulation in spontaneously hypertensive rats (SHR), and further determine the effect of β-arrestin1 on AT1R expression in the RVLM. Methods: The animal model of β-arrestin1 overexpression was induced by bilateral injection of adeno-associated virus containing Arrb1 gene (AAV-Arrb1) into the RVLM of WKY and SHR. Results: β-arrestin1 was expressed on the pre-sympathetic neurons in the RVLM, and its expression in the RVLM was significantly (P < 0.05) downregulated by an average of 64% in SHR than WKY. Overexpression of β-arrestin1 in SHR significantly decreased baseline levels of blood pressure and renal sympathetic nerve activity, and attenuated cardiovascular effects induced by RVLM injection of angiotensin II (100 pmol). Furthermore, β-arrestin1 overexpression in the RVLM significantly reduced the expression of AT1R by 65% and NF-κB p65 phosphorylation by 66% in SHR. It was confirmed that β-arrestin1 overexpression in the RVLM led to an enhancement of interaction between β-arrestin1 and IκB-α. Conclusion: Overexpression of β-arrestin1 in the RVLM reduces BP and sympathetic outflow in hypertension, which may be associated with NFκB-mediated AT1R downregulation.
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Affiliation(s)
- Jia-Cen Sun
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Bing Liu
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Ru-Wen Zhang
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Pei-Lei Jiao
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Xing Tan
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Yang-Kai Wang
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
| | - Wei-Zhong Wang
- Department of Physiology and Center of Polar Medical Research, Second Military Medical University, Shanghai, China
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Aksoydan B, Kantarcioglu I, Erol I, Salmas RE, Durdagi S. Structure-based design of hERG-neutral antihypertensive oxazalone and imidazolone derivatives. J Mol Graph Model 2017; 79:103-117. [PMID: 29156380 DOI: 10.1016/j.jmgm.2017.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Angiotensin II receptor type 1 (AT1) antagonists are the most recent drug class against hypertension. Recently first crystal structure of AT1 receptor is deposited to the protein data bank (PDB ID: 4YAY). In this work, several molecular screening methods such as molecular docking and de novo design studies were performed and it is found that oxazolone and imidazolone derivatives reveal similar/better interaction energy profiles compared to the FDA approved sartan molecules at the binding site of the AT1 receptor. A database consisting of 3500-fragments were used to enumerate de novo designed imidazolone and oxazolone derivatives and hereby more than 50000 novel small molecules were generated. These derivatives were then used in high throughput virtual screening simulations (Glide/HTVS) to find potent hit molecules. In addition, virtual screening of around 18 million small drug-like compounds from ZINC database were screened at the binding pocket of the AT1 receptor via Glide/HTVS method. Filtered structures were then used in more sophisticated molecular docking simulations protocols (i.e., Glide/SP; Glide/XP; Glide/IFD; Glide/QPLD, and GOLD). However, the K+ ion channel/drug interactions should also be considered in studies implemented in molecular level against their cardiovascular risks. Thus, selected compounds with high docking scores via all diverse docking algorithms are also screened at the pore domain regions of human ether-a-go-go-related gene (hERG1) K+ channel to remove the high affinity hERG1 blocking compounds. High docking scored compounds at the AT1 with low hERG1 affinity is considered for long molecular dynamics (MD) simulations. Post-processing analysis of MD simulations assisted for better understanding of molecular mechanism of studied compounds at the binding cavity of AT1 receptor. Results of this study can be useful for designing of novel and safe AT1 inhibitors.
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Affiliation(s)
- Busecan Aksoydan
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey
| | - Isik Kantarcioglu
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey
| | - Ismail Erol
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Department of Chemistry, Gebze Technical University, Kocaeli, Turkey
| | - Ramin Ekhteiari Salmas
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey
| | - Serdar Durdagi
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey.
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Publisher's note. J Mol Graph Model 2017; 77:240-249. [DOI: 10.1016/j.jmgm.2017.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 11/17/2022]
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