1
|
McNaught-Flores DA, Kooistra AJ, Chen YC, Arias-Montano JA, Panula P, Leurs R. Pharmacological Characterization of the Zebrafish (Danio Rerio) Histamine H 1 Receptor Reveals the Involvement of the Second Extracellular Loop in the Binding of Histamine. Mol Pharmacol 2024; 105:84-96. [PMID: 37977823 DOI: 10.1124/molpharm.123.000741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/11/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
The zebrafish (Danio rerio) histamine H1 receptor gene (zfH1R) was cloned in 2007 and reported to be involved in fish locomotion. Yet, no detailed characterization of its pharmacology and signaling properties have so far been reported. In this study, we pharmacologically characterized the zfH1R expressed in HEK-293T cells by means of [3H]-mepyramine binding and G protein-signaling assays. The zfH1R [dissociation constant (KD), 0.7 nM] displayed similar affinity for the antagonist [3H]-mepyramine as the human histamine H1 receptor (hH1R) (KD, 1.5 nM), whereas the affinity for histamine is 100-fold higher than for the human H1R. The zfH1R couples to Gαq/11 proteins and activates several reporter genes, i.e., NFAT, NFϰB, CRE, VEGF, COX-2, SRE, and AP-1, and zfH1R-mediated signaling is prevented by the Gαq/11 inhibitor YM-254890 and the antagonist mepyramine. Molecular modeling of the zfH1R and human H1R shows that the binding pockets are identical, implying that variations along the ligand binding pathway could underly the differences in histamine affinity instead. Targeting differentially charged residues in extracellular loop 2 (ECL2) using site-directed mutagenesis revealed that Arg21045x55 is most likely involved in the binding process of histamine in zfH1R. This study aids the understanding of the pharmacological differences between H1R orthologs and the role of ECL2 in histamine binding and provides fundamental information for the understanding of the histaminergic system in the zebrafish. SIGNIFICANCE STATEMENT: The use of the zebrafish as in vivo models in neuroscience is growing exponentially, which asks for detailed characterization of the aminergic neurotransmitter systems in this model. This study is the first to pharmacologically characterize the zebrafish histamine H1 receptor after expression in HEK-293T cells. The results show a high pharmacological and functional resemblance with the human ortholog but also reveal interesting structural differences and unveils an important role of the second extracellular loop in histamine binding.
Collapse
Affiliation(s)
- Daniel A McNaught-Flores
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| | - Albert J Kooistra
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| | - Yu-Chia Chen
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| | - Jose-Antonio Arias-Montano
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| | - Pertti Panula
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| | - Rob Leurs
- Amsterdam Institute for Molecules, Medicines, and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (D.A.M.-F., A.J.K., R.L.); Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (A.J.K.); Department of Anatomy, University of Helsinki, Helsinki, Finland (Y.-C.C., P.P.); and Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México (J.-A.A.-M.)
| |
Collapse
|
2
|
Liu C, Kang ZY, Yin Z, Xiao Y, Liu W, Zhao Y, Li DH. Levels of angiotensin II type-1 receptor antibodies and endothelin-1 type-A receptor antibodies correlate with antibody-mediated rejection and poor graft function in kidney-transplantation patients. Transpl Immunol 2022; 74:101674. [PMID: 35901953 DOI: 10.1016/j.trim.2022.101674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/16/2022] [Accepted: 07/16/2022] [Indexed: 10/16/2022]
Abstract
OBJECTIVE Angiotensin II type-1 receptor antibodies (AT1R-Ab) and endothelin-1 type-A receptor antibodies (ETAR-Ab) are non-human leukocyte antigen (HLA) antibodies that can elicit adverse effects on kidney transplantation (KT) outcomes. We investigated the correlation between levels of AT1R-Ab and ETAR-Ab and postoperative outcomes in KT recipients. METHODS Pre-KT and post-KT serum from 79 patients was collected. Post-KT serum was collected within 1 year after KT or simultaneously as the biopsy. Levels of AT1R-Ab and ETAR-Ab were measured using enzyme-linked immunosorbent assay kits. AT1R-Ab >17.0 U/mL and ETAR-Ab >10.0 U/mL was considered to denote positivity according to manufacturer recommendations. We measured donor-specific antibodies against human leukocyte antigens (HLA-DSA) levels using LABScreen™ single-antigen kits. RESULTS Seventy-nine (54 men, 25 women) formed the study cohort. Seven (8.7%) patients were positive for AT1R-Ab, 25 (31.6%) patients were positive for both AT1R-Ab and ETAR-Ab, and 47 (59.5%) were negative for both antibodies at all time points. No patients died during the study period. Patients with both AT1R-Ab and ETAR-Ab were associated with a higher prevalence of antibody-mediated rejection (AMR) and lower estimated glomerular filtration rate, but not allograft loss or delayed graft function. AT1R-Ab were associated with T-cell-mediated rejection, but the association was not significant. HLA-DSA were associated significantly with a higher creatinine level in serum at 12 months and 24 months in patients with AT1R-Ab and/or ETAR-Ab. CONCLUSIONS AT1R-Ab, ETAR-Ab, and HLA-DSA were associated with a higher prevalence of AMR and decline in graft function. Measurement of levels of AT1R-Ab and ETAR-Ab in KT patients may be useful for stratification of immunological risk and identification of patients at a high risk of adverse graft outcome.
Collapse
Affiliation(s)
- Chun Liu
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Zhong-Yu Kang
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Zhiqi Yin
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China; Department of Pathology, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Yanli Xiao
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Wei Liu
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Yuan Zhao
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China
| | - Dai-Hong Li
- Department of Blood Transfusion, Tianjin First Central Hospital, School of Medicine, NanKai University, 24 Fukang Road, Tianjin, Nankai, China.
| |
Collapse
|
3
|
Speck D, Kleinau G, Szczepek M, Kwiatkowski D, Catar R, Philippe A, Scheerer P. Angiotensin and Endothelin Receptor Structures With Implications for Signaling Regulation and Pharmacological Targeting. Front Endocrinol (Lausanne) 2022; 13:880002. [PMID: 35518926 PMCID: PMC9063481 DOI: 10.3389/fendo.2022.880002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/18/2022] [Indexed: 12/28/2022] Open
Abstract
In conjunction with the endothelin (ET) type A (ETAR) and type B (ETBR) receptors, angiotensin (AT) type 1 (AT1R) and type 2 (AT2R) receptors, are peptide-binding class A G-protein-coupled receptors (GPCRs) acting in a physiologically overlapping context. Angiotensin receptors (ATRs) are involved in regulating cell proliferation, as well as cardiovascular, renal, neurological, and endothelial functions. They are important therapeutic targets for several diseases or pathological conditions, such as hypertrophy, vascular inflammation, atherosclerosis, angiogenesis, and cancer. Endothelin receptors (ETRs) are expressed primarily in blood vessels, but also in the central nervous system or epithelial cells. They regulate blood pressure and cardiovascular homeostasis. Pathogenic conditions associated with ETR dysfunctions include cancer and pulmonary hypertension. While both receptor groups are activated by their respective peptide agonists, pathogenic autoantibodies (auto-Abs) can also activate the AT1R and ETAR accompanied by respective clinical conditions. To date, the exact mechanisms and differences in binding and receptor-activation mediated by auto-Abs as opposed to endogenous ligands are not well understood. Further, several questions regarding signaling regulation in these receptors remain open. In the last decade, several receptor structures in the apo- and ligand-bound states were determined with protein X-ray crystallography using conventional synchrotrons or X-ray Free-Electron Lasers (XFEL). These inactive and active complexes provide detailed information on ligand binding, signal induction or inhibition, as well as signal transduction, which is fundamental for understanding properties of different activity states. They are also supportive in the development of pharmacological strategies against dysfunctions at the receptors or in the associated signaling axis. Here, we summarize current structural information for the AT1R, AT2R, and ETBR to provide an improved molecular understanding.
Collapse
Affiliation(s)
- David Speck
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Gunnar Kleinau
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Michal Szczepek
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Dennis Kwiatkowski
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Rusan Catar
- Department of Nephrology and Critical Care Medicine, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Aurélie Philippe
- Department of Nephrology and Medical Intensive Care, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, Berlin, Germany
| | - Patrick Scheerer
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| |
Collapse
|
4
|
Philippe A, Kleinau G, Gruner JJ, Wu S, Postpieszala D, Speck D, Heidecke H, Dowell SJ, Riemekasten G, Hildebrand PW, Kamhieh-Milz J, Catar R, Szczepek M, Dragun D, Scheerer P. Molecular Effects of Auto-Antibodies on Angiotensin II Type 1 Receptor Signaling and Cell Proliferation. Int J Mol Sci 2022; 23:ijms23073984. [PMID: 35409344 PMCID: PMC8999261 DOI: 10.3390/ijms23073984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/16/2022] Open
Abstract
The angiotensin II (Ang II) type 1 receptor (AT1R) is involved in the regulation of blood pressure (through vasoconstriction) and water and ion homeostasis (mediated by interaction with the endogenous agonist). AT1R can also be activated by auto-antibodies (AT1R-Abs), which are associated with manifold diseases, such as obliterative vasculopathy, preeclampsia and systemic sclerosis. Knowledge of the molecular mechanisms related to AT1R-Abs binding and associated signaling cascade (dys-)regulation remains fragmentary. The goal of this study was, therefore, to investigate details of the effects of AT1R-Abs on G-protein signaling and subsequent cell proliferation, as well as the putative contribution of the three extracellular receptor loops (ELs) to Abs-AT1R signaling. AT1R-Abs induced nuclear factor of activated T-cells (NFAT) signaling, which reflects Gq/11 and Gi activation. The impact on cell proliferation was tested in different cell systems, as well as activation-triggered receptor internalization. Blockwise alanine substitutions were designed to potentially investigate the role of ELs in AT1R-Abs-mediated effects. First, we demonstrate that Ang II-mediated internalization of AT1R is impeded by binding of AT1R-Abs. Secondly, exclusive AT1R-Abs-induced Gq/11 activation is most significant for NFAT stimulation and mediates cell proliferation. Interestingly, our studies also reveal that ligand-independent, baseline AT1R activation of Gi signaling has, in turn, a negative effect on cell proliferation. Indeed, inhibition of Gi basal activity potentiates proliferation triggered by AT1R-Abs. Finally, although AT1R containing EL1 and EL3 blockwise alanine mutations were not expressed on the human embryonic kidney293T (HEK293T) cell surface, we at least confirmed that parts of EL2 are involved in interactions between AT1R and Abs. This current study thus provides extended insights into the molecular action of AT1R-Abs and associated mechanisms of interrelated pathogenesis.
Collapse
Affiliation(s)
- Aurélie Philippe
- Berlin Institute of Health at Charité—Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, D-10178 Berlin, Germany
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
- Correspondence: (A.P.); (P.S.); Tel.: +49-30450559318 (A.P.); +49-30450524178 (P.S.)
| | - Gunnar Kleinau
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany; (G.K.); (D.S.); (P.W.H.); (M.S.)
| | - Jason Jannis Gruner
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
- Vivantes Humboldt-Klinikum, Department of Urology, D-13509 Berlin, Germany
| | - Sumin Wu
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
| | - Daniel Postpieszala
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
| | - David Speck
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany; (G.K.); (D.S.); (P.W.H.); (M.S.)
| | | | | | - Gabriela Riemekasten
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Members of the German Center for Lung Research (DZL), D-23845 Borstel, Germany;
- University of Lübeck, University Clinic Schleswig-Holstein, Department of Rheumatology and Clinical Immunology, Campus Lübeck, D-23538 Lübeck, Germany
| | - Peter W. Hildebrand
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany; (G.K.); (D.S.); (P.W.H.); (M.S.)
- Leipzig University, Medical Faculty Leipzig, Institute for Medical Physics and Biophysics, D-04107 Leipzig, Germany
- Berlin Institute of Health at Charité—Universitätsmedizin Berlin, D-10178 Berlin, Germany
| | - Julian Kamhieh-Milz
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Transfusion Medicine, D-10117 Berlin, Germany;
| | - Rusan Catar
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
| | - Michal Szczepek
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany; (G.K.); (D.S.); (P.W.H.); (M.S.)
| | - Duska Dragun
- Berlin Institute of Health at Charité—Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, D-10178 Berlin, Germany
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Nephrology and Medical Intensive Care, Campus Virchow Klinikum, D-13353 Berlin, Germany; (J.J.G.); (S.W.); (D.P.); (R.C.)
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, D-10117 Berlin, Germany
| | - Patrick Scheerer
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany; (G.K.); (D.S.); (P.W.H.); (M.S.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, D-13353 Berlin, Germany
- Correspondence: (A.P.); (P.S.); Tel.: +49-30450559318 (A.P.); +49-30450524178 (P.S.)
| |
Collapse
|
5
|
Nicoli A, Dunkel A, Giorgino T, de Graaf C, Di Pizio A. Classification Model for the Second Extracellular Loop of Class A GPCRs. J Chem Inf Model 2022; 62:511-522. [PMID: 35113559 DOI: 10.1021/acs.jcim.1c01056] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The extracellular loop 2 (ECL2) is the longest and the most diverse loop among class A G protein-coupled receptors (GPCRs). It connects the transmembrane (TM) helices 4 and 5 and contains a highly conserved cysteine through which it is bridged with TM3. In this paper, experimental ECL2 structures were analyzed based on their sequences, shapes, and intramolecular contacts. To take into account the flexibility, we incorporated into our analyses information from the molecular dynamics trajectories available on the GPCRmd website. Despite the high sequence variability, shapes of the analyzed structures, defined by the backbone volume overlaps, can be clustered into seven main groups. Conformational differences within the clusters can be then identified by intramolecular interactions with other GPCR structural domains. Overall, our work provides a reorganization of the structural information of the ECL2 of class A GPCR subfamilies, highlighting differences and similarities on sequence and conformation levels.
Collapse
Affiliation(s)
- Alessandro Nicoli
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany
| | - Andreas Dunkel
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany
| | - Toni Giorgino
- Biophysics Institute, National Research Council (CNR-IBF), 20133 Milan, Italy
| | - Chris de Graaf
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abington, Cambridge CB21 6DG, U.K
| | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, 85354 Freising, Germany
| |
Collapse
|
6
|
Novel allosteric ligands of the angiotensin receptor AT1R as autoantibody blockers. Proc Natl Acad Sci U S A 2021; 118:2019126118. [PMID: 34380734 DOI: 10.1073/pnas.2019126118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
While orthosteric ligands of the angiotensin II (AngII) type 1 receptor (AT1R) are available for clinical and research applications, allosteric ligands are not known for this important G protein-coupled receptor (GPCR). Allosteric ligands are useful tools to modulate receptor pharmacology and subtype selectivity. Here, we report AT1R allosteric ligands for a potential application to block autoimmune antibodies. The epitope of autoantibodies for AT1R is outside the orthosteric pocket in the extracellular loop 2. A molecular dynamics simulation study of AT1R structure reveals the presence of a druggable allosteric pocket encompassing the autoantibody epitope. Small molecule binders were then identified for this pocket using structure-based high-throughput virtual screening. The top 18 hits obtained inhibited the binding of antibody to AT1R and modulated agonist-induced calcium response of AT1R. Two compounds out of 18 studied in detail exerted a negative allosteric modulator effect on the functions of the natural agonist AngII. They blocked antibody-enhanced calcium response and reactive oxygen species production in vascular smooth muscle cells as well as AngII-induced constriction of blood vessels, demonstrating their efficacy in vivo. Our study thus demonstrates the feasibility of discovering inhibitors of the disease-causing autoantibodies for GPCRs. Specifically, for AT1R, we anticipate development of more potent allosteric drug candidates for intervention in autoimmune maladies such as preeclampsia, bilateral adrenal hyperplasia, and the rejection of organ transplants.
Collapse
|
7
|
Sarkar P, Mozumder S, Bej A, Mukherjee S, Sengupta J, Chattopadhyay A. Structure, dynamics and lipid interactions of serotonin receptors: excitements and challenges. Biophys Rev 2020; 13:10.1007/s12551-020-00772-8. [PMID: 33188638 PMCID: PMC7930197 DOI: 10.1007/s12551-020-00772-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is an intrinsically fluorescent neurotransmitter found in organisms spanning a wide evolutionary range. Serotonin exerts its diverse actions by binding to distinct cell membrane receptors which are classified into many groups. Serotonin receptors are involved in regulating a diverse array of physiological signaling pathways and belong to the family of either G protein-coupled receptors (GPCRs) or ligand-gated ion channels. Serotonergic signaling appears to play a key role in the generation and modulation of various cognitive and behavioral functions such as sleep, mood, pain, anxiety, depression, aggression, and learning. Serotonin receptors act as drug targets for a number of diseases, particularly neuropsychiatric disorders. The signaling mechanism and efficiency of serotonin receptors depend on their amazing ability to rapidly access multiple conformational states. This conformational plasticity, necessary for the wide variety of functions displayed by serotonin receptors, is regulated by binding to various ligands. In this review, we provide a succinct overview of recent developments in generating and analyzing high-resolution structures of serotonin receptors obtained using crystallography and cryo-electron microscopy. Capturing structures of distinct conformational states is crucial for understanding the mechanism of action of these receptors, which could provide important insight for rational drug design targeting serotonin receptors. We further provide emerging information and insight from studies on interactions of membrane lipids (such as cholesterol) with serotonin receptors. We envision that a judicious combination of analysis of high-resolution structures and receptor-lipid interaction would allow a comprehensive understanding of GPCR structure, function and dynamics, thereby leading to efficient drug discovery.
Collapse
Affiliation(s)
- Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Sukanya Mozumder
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | - Aritra Bej
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Sujoy Mukherjee
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Jayati Sengupta
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | | |
Collapse
|
8
|
Kiriakidi S, Chatzigiannis C, Papaemmanouil C, Tzakos AG, Mavromoustakos T. Exploring the role of the membrane bilayer in the recognition of candesartan by its GPCR AT1 receptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183142. [PMID: 31830465 DOI: 10.1016/j.bbamem.2019.183142] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/13/2019] [Accepted: 11/28/2019] [Indexed: 01/20/2023]
Abstract
Cardiovascular diseases and hypertension in particular are major health risks worldwide and the improvement on their treatment will be beneficial for the human health. AT1R antagonists belong to the sartans family that targets the renin-angiotensin aldosterone system (RAAS) through blocking the hormone angiotensin II to exert its detrimental effects in pathological states. As a consequence, they are beneficial to treat hypertension, diabetes related kidney failure and hyperaemic episodes. Long unbiased Molecular Dynamics (MD) simulations are performed in order to explore candesartan's possible 2D and 3D diffusion mechanisms towards AT1R receptor. 3D diffusion mechanism is referred to the direct binding of the AT1 antagonist candesartan to the AT1R 3D structure (PDB ID: 4YAY). 2D diffusion mechanism involves first, the incorporation of candesartan in the bilayer core and then its localization on the AT1R binding cavity, through a diffusion mechanism. The obtained results indicate that membranes interact significantly with the neutral form of candesartan, which is indeed approaching the receptors' active site through diffusion via the lipids. On the other hand, the deprotonated form of the drug is interacting with AT1R's extracellular loop and fails to enter the membrane, pointing out the importance of the pH microenvironment around the receptor. To validate the calculated diffusion coefficients of the drug in the lipid bilayers 2D DOSY NMR experiments were recorded and they were in good agreement. Information on the impact that has the interaction of candesartan with the membrane is very important for the rationally design and development of potent ARBs. Thus, its conformational features as well as its localization in the membrane core have to be thoroughly explored.
Collapse
Affiliation(s)
- Sofia Kiriakidi
- National and Kapodistrian University of Athens, Department of Chemistry, Athens, Greece
| | - Christos Chatzigiannis
- University of Ioannina, Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Christina Papaemmanouil
- University of Ioannina, Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Andreas G Tzakos
- University of Ioannina, Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Thomas Mavromoustakos
- National and Kapodistrian University of Athens, Department of Chemistry, Athens, Greece.
| |
Collapse
|
9
|
Kuenzel WJ, Kang SW, Jurkevich A. The vasotocinergic system and its role in the regulation of stress in birds. VITAMINS AND HORMONES 2019; 113:183-216. [PMID: 32138948 DOI: 10.1016/bs.vh.2019.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The regulation of stress in birds includes a complex interaction of neural systems affecting the hypothalamic-pituitary-adrenal (HPA) axis. In addition to the hypothalamic paraventricular nucleus, a structure called the nucleus of the hippocampal commissure likewise affects the output of pituitary stress hormones and appears to be unique to avian species. Within the anterior pituitary, the avian V1a and V1b receptors were found in corticotropes. Based on our studies with central administration of hormones in the chicken, corticotropic releasing hormone (CRH) is a more potent ACTH secretagogue than arginine vasotocin (AVT). In contrast, when applied peripherally, AVT is more efficacious. Co-administration of AVT and CRH peripherally, resulted in a synergistic stimulation of corticosterone release. Data suggest receptor oligomerization as one possible mechanism. In birds, vasotocin receptors associated with stress responses include the V1a and V1b receptors. Three-dimensional, homology-based structural models of the avian V1aR were built to test agonists and antagonists for each receptor that were screened by molecular docking to map their binding sites on each receptor. Additionally, binding affinity values for each available peptide antagonist to the V1aR and V1bR were determined. An anterior pituitary primary culture system was developed to determine how effective each antagonist blocked the function of each receptor in culture when stimulated by a combination of AVT/CRH administration. Use of an antagonist in subsequent in vivo studies identified the V1aR in regulating food intake in birds. The V1aR was likewise found in circumventricular organs of the brain, suggesting a possible function in stress.
Collapse
Affiliation(s)
- Wayne J Kuenzel
- Poultry Science Center, University of Arkansas, Fayetteville, AR, United States.
| | - Seong W Kang
- Poultry Science Center, University of Arkansas, Fayetteville, AR, United States
| | - Alexander Jurkevich
- Molecular Cytology Research Core Facility, University of Missouri, Columbia, MO, United States
| |
Collapse
|
10
|
Philogene MC, Johnson T, Vaught AJ, Zakaria S, Fedarko N. Antibodies against Angiotensin II Type 1 and Endothelin A Receptors: Relevance and pathogenicity. Hum Immunol 2019; 80:561-567. [PMID: 31010696 PMCID: PMC8015780 DOI: 10.1016/j.humimm.2019.04.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 12/25/2022]
Abstract
Antibodies against two G-protein coupled receptors (GPCRs), angiotensin II type 1 receptor (AT1R) and endothelin A receptor (ETAR) are among a growing number of autoantibodies that are found to be associated with allograft dysfunction. AT1R antibodies (AT1Rabs) and ETAR antibodies (ETARabs) have been shown to activate their target receptors and affect signaling pathways. Multiple single center reports have shown an association between presence of these antibodies and acute or chronic rejection and graft loss in kidney, heart, liver, lung and composite tissue transplantations. However, the characteristics of patients that are most likely to develop adverse outcomes, the phenotypes associated with graft damage solely due to these antibodies, and the antibody titer required to cause dysfunction are areas that remain controversial. This review compiles existing knowledge on the effect of antibodies against GPCRs in other diseases in order to bridge the gap in knowledge within transplantation biology. Future areas for research are highlighted and include the need for functional assays and treatment protocols for transplant patients who present with AT1Rabs and ETARabs. Understanding how antibodies that activate GPCRs influence transplantation outcome will have direct clinical implications for preemptive evaluation of transplant candidates as well as the post-transplant care of organ recipients.
Collapse
Affiliation(s)
- Mary Carmelle Philogene
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
| | - Tory Johnson
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Arthur Jason Vaught
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sammy Zakaria
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Neal Fedarko
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| |
Collapse
|
11
|
Oakes V, Domene C. Influence of Cholesterol and Its Stereoisomers on Members of the Serotonin Receptor Family. J Mol Biol 2019; 431:1633-1649. [PMID: 30857969 DOI: 10.1016/j.jmb.2019.02.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 01/24/2023]
Abstract
Despite the ubiquity of cholesterol within the cell membrane, the mechanism by which it influences embedded proteins remains elusive. Numerous G-protein coupled receptors exhibit dramatic responses to membrane cholesterol with regard to the ligand-binding affinity and functional properties, including the 5-HT receptor family. Here, we use over 25 μs of unbiased atomistic molecular dynamics simulations to identify cholesterol interaction sites in the 5-HT1B and 5-HT2B receptors and evaluate their impact on receptor structure. Susceptibility to membrane cholesterol is shown to be subtype dependent and determined by the quality of interactions between the extracellular loops. Charged residues are essential for maintaining the arrangement of the extracellular surface in 5-HT2B; in the absence of such interactions, the extracellular surface of the 5-HT1B is malleable, populating a number of distinct conformations. Elevated cholesterol density near transmembrane helix 4 is considered to be conducive to the conformation of extracellular loop 2. Occupation of this site is also shown to be stereospecific, illustrated by differential behavior of nat-cholesterol isomers, ent- and epi-cholesterol. In simulations containing the endogenous agonist, serotonin, cholesterol binding at transmembrane helix 4 biases bound serotonin molecules toward an unexpected binding mode in the extended binding pocket. The results highlight the capability of membrane cholesterol to influence the mobility of the extracellular surface in the 5-HT1 receptor family and manipulate the architecture of the extracellular ligand-binding pocket.
Collapse
Affiliation(s)
- Victoria Oakes
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Carmen Domene
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK; Department of Chemistry, University of Oxford, Oxford, OX1 3TA, Oxford, UK.
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Pan Y, Zhou Z, Zhang H, Zhou Y, Li Y, Li C, Chen X, Yang S, Liao Y, Qiu Z. The ATRQβ-001 vaccine improves cardiac function and prevents postinfarction cardiac remodeling in mice. Hypertens Res 2018; 42:329-340. [PMID: 30587854 DOI: 10.1038/s41440-018-0185-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/09/2018] [Accepted: 09/09/2018] [Indexed: 11/09/2022]
Abstract
We invented the ATRQβ-001 hypertension vaccine, which targeted angiotensin II type 1 receptor (AT1R) and showed a desirable blocking effect for AT1R. The purpose of this study was to investigate whether the ATRQβ-001 vaccine could improve cardiac function and prevent cardiac remodeling after acute myocardial infarction (AMI). C57BL/6 male mice were randomly assigned into four groups: sham + VLP, MI + VLP, MI + ATRQβ-001, and MI + valsartan. Mice were administered Qβ virus-like particle (Qβ-VLP, 100 μg/time), ATRQβ-001 vaccine (100 μg/time), and valsartan (6 mg/kg/day) before AMI, which was induced by permanently ligating the left anterior descending coronary artery. The effect of the ATRQβ-001 vaccine on cardiac function and cardiac remodeling was observed by following up for 1 week, 4 weeks, and 12 weeks post MI. The ATRQβ-001 vaccine significantly reduced sudden cardiac death and increased survival rates (compared with MI + VLP, 80% versus 55% and mean estimate (days) 68.4 ± 7.0 versus 47.8 ± 8.9, respectively; p = 0.046) post MI. Echocardiography showed that the ATRQβ-001 vaccine remarkably improved cardiac function (left ventricular ejection fraction, 24.8 ± 7.0% versus 13.2 ± 3.8%, p = 0.005) post MI. Histological analysis revealed that the ATRQβ-001 vaccine obviously mitigated myocardial inflammation, apoptosis, and fibrosis after AMI. Further, the ATRQβ-001 vaccine significantly inhibited the TGF-β1/Smad2/3 signaling pathway. Assessment of the renin-angiotensin system (RAS) demonstrated that the ATRQβ-001 vaccine did not cause obvious feedback of circulating RAS, but prominently attenuated the expression of AT1R, compared with the other groups at 4 and 12 weeks after AMI. In conclusion, the ATRQβ-001 vaccine decreased mortality and improved cardiac function and remodeling after AMI.
Collapse
Affiliation(s)
- Yajie Pan
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zihua Zhou
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hongrong Zhang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yanzhao Zhou
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yingying Li
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Chang Li
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xiao Chen
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Shijun Yang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yuhua Liao
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zhihua Qiu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. .,Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. .,Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| |
Collapse
|
15
|
Billard E, Hébert TE, Chatenet D. Discovery of New Allosteric Modulators of the Urotensinergic System through Substitution of the Urotensin II-Related Peptide (URP) Phenylalanine Residue. J Med Chem 2018; 61:8707-8716. [PMID: 30183282 DOI: 10.1021/acs.jmedchem.8b00789] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Urotensin II (UII) and urotensin II-related peptide (URP) are functionally selective, suggesting that these two hormones might play distinct physiological role through different interactions with their cognate receptor UT. Hypothesizing that the Phe3 residue of URP, which is also present in UII, is a key-element of its specific UT activation, we evaluated the impact of its replacement by non-natural amino acids in URP. Each compound was evaluated for its ability to bind UT, induce rat aortic ring contraction, and activate Gq, G12, and β-arrestin 1 signaling pathways. Such modifications impaired contractile efficacy, reflected by a reduced aptitude to activate G12 in URP but not in the truncated but equipotent UII4-11. Moreover, we have identified two structurally different UT modulators: [d-Phe(pI)3]URP and [Bip3]URP, which exert a probe-dependent action against UII and URP. These compounds should help us understand the specific roles of these hormones as well as guide further therapeutic development.
Collapse
Affiliation(s)
- Etienne Billard
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP) , Université du Québec , Ville de Laval , Québec H7V 1B7 , Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics , McGill University , Montréal , Québec H3A 1A3 , Canada
| | - David Chatenet
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP) , Université du Québec , Ville de Laval , Québec H7V 1B7 , Canada
| |
Collapse
|
16
|
Kang SW, Jayanthi S, Nagarajan G, Suresh Kumar TK, Kuenzel WJ. Identification of avian vasotocin receptor subtype-specific antagonists involved in the stress response of the chicken, Gallus gallus. J Biomol Struct Dyn 2018; 37:1685-1699. [PMID: 29658387 DOI: 10.1080/07391102.2018.1464957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vasotocin 1a and 1b receptors (V1aR and V1bR) have been shown to play important roles in the neuroendocrine regulation of stress responses via the anterior pituitary (AP) of birds. To identify effective subtype-specific antagonists for the chicken V1aR (cV1aR) and cV1bR, potential antagonists to the mammalian V1R were screened against the cV1aR and cV1bR 3D structural models by molecular docking analysis with determination of binding pocket/amino acid residues involved in the interaction. The antagonistic effects of the selected ligands were examined by measuring pro-opiomelanocortin (POMC) heteronuclear RNA (hnPOMC) levels following the in vitro stress administration to primary chicken AP cells. Results of in silico analysis showed that the Manning compound and several other antagonists were bound to cV1bR with higher affinity than the natural agonist, arginine vasotocin (AVT). Similarities and differences in the antagonist-receptor binding interface with receptors were characterized for each ligand. Non-peptide mammalian V1bR antagonists, SSR-149415 and L-368899, were shown to be effective and had an additive effect in blocking POMC hnRNA expression in pituitary cell culture studies. SR-49059 antagonized the effect(s) of AVT/CRH on the downregulation of the cV1aR and the upregulation of the cCRH-R2 expression but not the cV1bR and cCRH-R1. The Manning compound antagonized the downregulation of cV1aR, cV1bR and cCRH-R1 and the upregulation of cCRH-R2 expression. The specificity of antagonists apparently resulted from unique differences in the interacting residues and their binding affinities. Collectively, these results provide valuable leads for future development of novel compounds capable of blocking or attenuating the AP stress response of avian species and perhaps other non-mammalian vertebrates as well.
Collapse
Affiliation(s)
- Seong W Kang
- a Department of Poultry Sciences , University of Arkansas , Fayetteville , AR , USA
| | - Srinivas Jayanthi
- b Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , AR , USA
| | - Gurueswar Nagarajan
- a Department of Poultry Sciences , University of Arkansas , Fayetteville , AR , USA
| | | | - Wayne J Kuenzel
- a Department of Poultry Sciences , University of Arkansas , Fayetteville , AR , USA
| |
Collapse
|
17
|
Singh KD, Unal H, Desnoyer R, Karnik SS. Divergent Spatiotemporal Interaction of Angiotensin Receptor Blocking Drugs with Angiotensin Type 1 Receptor. J Chem Inf Model 2017; 58:182-193. [PMID: 29195045 DOI: 10.1021/acs.jcim.7b00424] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Crystal structures of the human angiotensin II type 1 receptor (AT1R) complex with the antihypertensive agent ZD7155 (PDB id: 4YAY ) and the blood pressure medication Benicar (PDB id: 4ZUD ) showed that binding poses of both antagonists are similar. This finding implies that clinically used angiotensin receptor blocking (ARB) drugs may interact in a similar fashion. However, clinically observed differences in pharmacological and therapeutic efficacies of ARBs lead to the question of whether the dynamic interactions of AT1R with ARBs vary. To address this, we performed induced-fit docking (IFD) of eight clinically used ARBs to AT1R followed by 200 ns molecular dynamic (MD) simulation. The experimental Ki values for ARBs correlated remarkably well with calculated free energy with R2 = 0.95 and 0.70 for AT1R-ARB models generated respectively by IFD and MD simulation. The eight ARB-AT1R complexes share a common set of binding residues. In addition, MD simulation results validated by mutagenesis data discovered distinctive spatiotemporal interactions that display unique bonding between an individual ARB and AT1R. These findings provide a reasonably broader picture reconciling the structure-based observations with clinical studies reporting efficacy variations for ARBs. The unique differences unraveled for ARBs in this study will be useful for structure-based design of the next generation of more potent and selective ARBs.
Collapse
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
| |
Collapse
|
18
|
Iglesias A, Cimadevila M, la Fuente RAD, Martí-Solano M, Cadavid MI, Castro M, Selent J, Loza MI, Brea J. Serotonin 2A receptor disulfide bridge integrity is crucial for ligand binding to different signalling states but not for its homodimerization. Eur J Pharmacol 2017; 815:138-146. [PMID: 28899696 DOI: 10.1016/j.ejphar.2017.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/28/2017] [Accepted: 09/08/2017] [Indexed: 02/06/2023]
Abstract
The serotonin 2A (5-HT2A) receptor is a G-protein coupled receptor (GPCR) with a conserved disulfide bridge formed by Cys148 (transmembrane helix 3, TM3) and Cys227 (extracellular loop 2, ECL-2). We hypothesized that disulfide bridges may determine serotonin 5-HT2A receptor functions such as receptor activation, functional selectivity and ligand recognition. We used the reducing agent dithiothreitol (DTT) to determine how the reduction of disulfide bridges affects radioligand binding, second messenger mobilization and receptor dimerization. A DTT-induced decrease in the number of binding sites (1190 ± 63.55 fmol/mg protein for control cells compared with 921.2 ± 60.84 fmol/mg protein for DTT-treated cells) as well as in the efficacy of both signalling pathways characterized was observed, although the affinity and potency were unchanged. Bioluminiscence resonance energy transfer (BRET) assays revealed the DTT treatment did not modify the homodimeric nature of serotonin 5-HT2A receptors. In molecular dynamic simulations, the ECL-2 of the receptor with a broken cysteine bond adopts a wider variety of conformations, some of which protrude deeper into the receptor orthosteric binding pocket leading to collapse of the pocket. A shrunken binding pocket would be incapable of accommodating lysergic acid diethylamide (LSD). Our findings suggest that the decrease of efficacy may be due to disruption of disulfide bridge between TM3 and ECL-2. This reveals the integrity of the ECL-2 epitope, which should be explored in the development of novel ligands acting as allosteric modulators of serotonin 5-HT2A receptors.
Collapse
Affiliation(s)
- Alba Iglesias
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - Marta Cimadevila
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - Rocío Ailim de la Fuente
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain; Molecular Pharmacology of G Protein-coupled Receptors Laboratory, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - María Martí-Solano
- GPCR Drug Discovery Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM) - Department of Experimental and Health Sciences of Pompeu Fabra University (UPF), Barcelona, Spain
| | - María Isabel Cadavid
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - Marián Castro
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain; Molecular Pharmacology of G Protein-coupled Receptors Laboratory, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - Jana Selent
- GPCR Drug Discovery Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM) - Department of Experimental and Health Sciences of Pompeu Fabra University (UPF), Barcelona, Spain
| | - María Isabel Loza
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain.
| | - José Brea
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain.
| |
Collapse
|
19
|
Woolley MJ, Conner AC. Understanding the common themes and diverse roles of the second extracellular loop (ECL2) of the GPCR super-family. Mol Cell Endocrinol 2017; 449:3-11. [PMID: 27899324 DOI: 10.1016/j.mce.2016.11.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/02/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
Abstract
The extracellular loops (ECLs) of G protein-coupled receptors (GPCRs) can bind directly to docked orthosteric or allosteric ligands, they can contain transient contact points for ligand entry into the transmembrane (TM) bundle and they can regulate the activation of the receptor signalling pathways. Of the three ECLs, ECL2 is the largest and most structurally diverse reflecting its functional importance. This has been shown through biochemical techniques and has been supported by the many subsequent crystal structures of GPCRs bound to both agonists and antagonists. ECL2 shares common structural features between (and sometimes across) receptor sub-families and can facilitate ligand entry to the TM core or act directly as a surface of the ligand-binding pocket. Structural similarities seem to underpin common binding mechanisms; however, where these exist, variations in primary sequence ensure ligand-binding specificity. This review will compare current understanding of the structural themes and main functional roles of ECL2 in ligand binding, activation and regulation of the major families of GPCRs.
Collapse
Affiliation(s)
- Michael J Woolley
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Alex C Conner
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
| |
Collapse
|
20
|
Takezako T, Unal H, Karnik SS, Node K. Current topics in angiotensin II type 1 receptor research: Focus on inverse agonism, receptor dimerization and biased agonism. Pharmacol Res 2017. [PMID: 28648738 DOI: 10.1016/j.phrs.2017.06.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although the octapeptide hormone angiotensin II (Ang II) regulates cardiovascular and renal homeostasis through the Ang II type 1 receptor (AT1R), overstimulation of AT1R causes various human diseases, such as hypertension and cardiac hypertrophy. Therefore, AT1R blockers (ARBs) have been widely used as therapeutic drugs for these diseases. Recent basic research and clinical studies have resulted in the discovery of interesting phenomena associated with AT1R function. For example, ligand-independent activation of AT1R by mechanical stress and agonistic autoantibodies, as well as via receptor mutations, has been shown to decrease the inverse agonistic efficacy of ARBs, though the molecular mechanisms of such phenomena had remained elusive until recently. Furthermore, although AT1R is believed to exist as a monomer, recent studies have demonstrated that AT1R can homodimerize and heterodimerize with other G-protein coupled receptors (GPCR), altering the receptor signaling properties. Therefore, formation of both AT1R homodimers and AT1R-GPCR heterodimer may be involved in the pathogenesis of human disease states, such as atherosclerosis and preeclampsia. Finally, biased AT1R ligands that can preferentially activate the β-arrestin-mediated signaling pathway have been discovered. Such β-arrestin-biased AT1R ligands may be better therapeutic drugs for cardiovascular diseases. New findings on AT1R described herein could provide a conceptual framework for application of ARBs in the treatment of diseases, as well as for novel drug development. Since AT1R is an extensively studied member of the GPCR superfamily encoded in the human genome, this review is relevant for understanding the functions of other members of this superfamily.
Collapse
Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart Research, Saga University, Saga, Japan; Medical Center for Student Health, Kobe University, Kobe, Japan.
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Koichi Node
- Department of Cardiovascular Medicine, Saga University, Japan
| |
Collapse
|
21
|
Zhang J, Wang M, Liang J, Zhang M, Liu XH, Ma L. The Presence of Anti-Angiotensin II Type-1 Receptor Antibodies Adversely Affect Kidney Graft Outcomes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14050500. [PMID: 28486415 PMCID: PMC5451951 DOI: 10.3390/ijerph14050500] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 03/24/2017] [Accepted: 04/19/2017] [Indexed: 12/29/2022]
Abstract
The aim of this study was to determine whether anti-angiotensin type 1 receptor antibodies (AT1R-Abs) are related to acute rejection (AR) and kidney graft failure in renal transplantation. We searched electronic databases including MEDLINE, EMBASE, and the ISI Web of Science databases for all studies on the association between anti-angiotensin type 1 receptor antibodies and kidney allograft outcomes updated to November 2016. Reference lists from included articles were also reviewed. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were extracted or calculated using a random-effects model. The potential sources of heterogeneity and publication bias were estimated. Nine studies enrolling 1771 subjects were retrieved in the meta-analysis. AT1R-Abs showed significant associations with increased risk of AR (RR = 1.66; 95% CI, 1.23–2.09). In addition, a significant relationship was found between AT1R-Abs and kidney graft failure compared with AR (RR = 3.02; 95% CI, 1.77–4.26). The results were essentially consistent among subgroups stratified by participant characteristics. These results demonstrated that the AT1R-Abs were associated with an elevated risk of kidney allograft outcomes, especially with kidney graft failure. Large-scale studies are still required to further verify these findings.
Collapse
Affiliation(s)
- Jian Zhang
- The First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, 277 Yanta West Road, Xi'an 710061, China.
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an 710004, China.
- School of Public Health, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an 710061, China.
| | - Mingxu Wang
- School of Public Health, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an 710061, China.
| | - Jun Liang
- School of Public Health, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an 710061, China.
| | - Ming Zhang
- Xi'an Honghui Hospital, 555 Friendship Road, Xi'an 710054, China.
| | - Xiao-Hong Liu
- The First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, 277 Yanta West Road, Xi'an 710061, China.
| | - Le Ma
- School of Public Health, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an 710061, China.
- Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an 710061, China.
| |
Collapse
|
22
|
Marina Robles L, Millán-Pacheco C, Pastor N, Del Río G. STRUCTURE-FUNCTION STUDIES OF THE ALPHA PHEROMONE RECEPTOR FROM YEAST. TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS 2017. [DOI: 10.1016/j.recqb.2016.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
23
|
Nguyen ATN, Baltos JA, Thomas T, Nguyen TD, Muñoz LL, Gregory KJ, White PJ, Sexton PM, Christopoulos A, May LT. Extracellular Loop 2 of the Adenosine A1 Receptor Has a Key Role in Orthosteric Ligand Affinity and Agonist Efficacy. Mol Pharmacol 2016; 90:703-714. [PMID: 27683014 DOI: 10.1124/mol.116.105007] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/27/2016] [Indexed: 12/14/2022] Open
Abstract
The adenosine A1 G protein-coupled receptor (A1AR) is an important therapeutic target implicated in a wide range of cardiovascular and neuronal disorders. Although it is well established that the A1AR orthosteric site is located within the receptor's transmembrane (TM) bundle, prior studies have implicated extracellular loop 2 (ECL2) as having a significant role in contributing to orthosteric ligand affinity and signaling for various G protein-coupled receptors (GPCRs). We thus performed extensive alanine scanning mutagenesis of A1AR-ECL2 to explore the role of this domain on A1AR orthosteric ligand pharmacology. Using quantitative analytical approaches and molecular modeling, we identified ECL2 residues that interact either directly or indirectly with orthosteric agonists and antagonists. Discrete mutations proximal to a conserved ECL2-TM3 disulfide bond selectively affected orthosteric ligand affinity, whereas a cluster of five residues near the TM4-ECL2 juncture influenced orthosteric agonist efficacy. A combination of ligand docking, molecular dynamics simulations, and mutagenesis results suggested that the orthosteric agonist 5'-N-ethylcarboxamidoadenosine binds transiently to an extracellular vestibule formed by ECL2 and the top of TM5 and TM7, prior to entry into the canonical TM bundle orthosteric site. Collectively, this study highlights a key role for ECL2 in A1AR orthosteric ligand binding and receptor activation.
Collapse
Affiliation(s)
- Anh T N Nguyen
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Jo-Anne Baltos
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Trayder Thomas
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Toan D Nguyen
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Laura López Muñoz
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Karen J Gregory
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Paul J White
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Patrick M Sexton
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Arthur Christopoulos
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| | - Lauren T May
- Monash Institute of Pharmaceutical Sciences (A.T.N.N., J.-A.B., T.T., L.L.M, K.J.G, P.J.W, P.M.S, A.C., L.T.M), Monash e-Research Centre (T.D.N), and Department of Pharmacology (A.T.N.N, J.-A.B., K.J.G., P.M.S., A.C., L.T.M), Monash University, Parkville, Victoria, Australia
| |
Collapse
|
24
|
Abstract
The development of post-transplantation antibodies against non-HLA autoantigens is associated with rejection and decreased long-term graft survival. Although our knowledge of non-HLA antibodies is incomplete, compelling experimental and clinical findings demonstrate that antibodies directed against autoantigens such as angiotensin type 1 receptor, perlecan and collagen, contribute to the process of antibody-mediated acute and chronic rejection. The mechanisms that underlie the production of autoantibodies in the setting of organ transplantation is an important area of ongoing investigation. Ischaemia-reperfusion injury, surgical trauma and/or alloimmune responses can result in the release of organ-derived autoantigens (such as soluble antigens, extracellular vesicles or apoptotic bodies) that are presented to B cells in the context of the transplant recipient's antigen presenting cells and stimulate autoantibody production. Type 17 T helper cells orchestrate autoantibody production by supporting the proliferation and maturation of autoreactive B cells within ectopic tertiary lymphoid tissue. Conversely, autoantibody-mediated graft damage can trigger alloimmunity and the development of donor-specific HLA antibodies that can act in synergy to promote allograft rejection. Identification of the immunologic phenotypes of transplant recipients at risk of non-HLA antibody-mediated rejection, and the development of targeted therapies to treat such rejection, are sorely needed to improve both graft and patient survival.
Collapse
|
25
|
Kleist AB, Getschman AE, Ziarek JJ, Nevins AM, Gauthier PA, Chevigné A, Szpakowska M, Volkman BF. New paradigms in chemokine receptor signal transduction: Moving beyond the two-site model. Biochem Pharmacol 2016; 114:53-68. [PMID: 27106080 DOI: 10.1016/j.bcp.2016.04.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Abstract
Chemokine receptor (CKR) signaling forms the basis of essential immune cellular functions, and dysregulated CKR signaling underpins numerous disease processes of the immune system and beyond. CKRs, which belong to the seven transmembrane domain receptor (7TMR) superfamily, initiate signaling upon binding of endogenous, secreted chemokine ligands. Chemokine-CKR interactions are traditionally described by a two-step/two-site mechanism, in which the CKR N-terminus recognizes the chemokine globular core (i.e. site 1 interaction), followed by activation when the unstructured chemokine N-terminus is inserted into the receptor TM bundle (i.e. site 2 interaction). Several recent studies challenge the structural independence of sites 1 and 2 by demonstrating physical and allosteric links between these supposedly separate sites. Others contest the functional independence of these sites, identifying nuanced roles for site 1 and other interactions in CKR activation. These developments emerge within a rapidly changing landscape in which CKR signaling is influenced by receptor PTMs, chemokine and CKR dimerization, and endogenous non-chemokine ligands. Simultaneous advances in the structural and functional characterization of 7TMR biased signaling have altered how we understand promiscuous chemokine-CKR interactions. In this review, we explore new paradigms in CKR signal transduction by considering studies that depict a more intricate architecture governing the consequences of chemokine-CKR interactions.
Collapse
Affiliation(s)
- Andrew B Kleist
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Anthony E Getschman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Joshua J Ziarek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA.
| | - Amanda M Nevins
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Pierre-Arnaud Gauthier
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Andy Chevigné
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| |
Collapse
|
26
|
Fuss A, Hope CM, Deayton S, Bennett GD, Holdsworth R, Carroll RP, Coates PTH. C4d-negative antibody-mediated rejection with high anti-angiotensin II type I receptor antibodies in absence of donor-specific antibodies. Nephrology (Carlton) 2016; 20:467-73. [PMID: 25726938 DOI: 10.1111/nep.12441] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2015] [Indexed: 12/28/2022]
Abstract
AIMS Acute antibody-mediated rejection can occur in absence of circulating donor-specific antibodies. Agonistic antibodies targeting the anti-angiotensin II type 1 receptor (anti-AT1 R) are emerging as important non-human leucocyte antigen (HLA) antibodies. Elevated levels of anti-angiotensin II receptor antibodies were first observed in kidney transplant recipients with malignant hypertension and allograft rejection. They have now been studied in three separate kidney transplant populations and associate to frequency of rejection, severity of rejection and graft failure. METHODS We report 11 cases of biopsy-proven, Complement 4 fragment d (C4d)-negative, acute rejection occurring without circulating donor-specific anti-HLA antibodies. In eight cases, anti-angiotensin receptor antibodies were retrospectively examined. The remaining three subjects were identified from our centre's newly instituted routine anti-angiotensin receptor antibody screening. RESULTS All subjects fulfilled Banff 2013 criteria for antibody-mediated rejection and all responded to anti-rejection therapy, which included plasma exchange and angiotensin receptor blocker therapy. CONCLUSIONS These cases support the routine assessment of anti-AT1 R antibodies in kidney transplant recipients to identify subjects at risk. Further studies will need to determine optimal assessment protocol and the effectiveness of pre-emptive treatment with angiotensin receptor blockers.
Collapse
Affiliation(s)
- Alexander Fuss
- The Centre for Clinical and Experimental Transplantation (CCET), Central Northern Adelaide Renal and Transplantation Services (CNARTS), Adelaide, South Australia, Australia.,Department of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher M Hope
- The Centre for Clinical and Experimental Transplantation (CCET), Central Northern Adelaide Renal and Transplantation Services (CNARTS), Adelaide, South Australia, Australia.,Department of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Susan Deayton
- Adelaide Division, Australian Red Cross Blood Service (ARCBS), Adelaide, South Australia, Australia
| | - Greg Donald Bennett
- Adelaide Division, Australian Red Cross Blood Service (ARCBS), Adelaide, South Australia, Australia
| | - Rhonda Holdsworth
- Adelaide Division, Australian Red Cross Blood Service (ARCBS), Adelaide, South Australia, Australia
| | - Robert P Carroll
- The Centre for Clinical and Experimental Transplantation (CCET), Central Northern Adelaide Renal and Transplantation Services (CNARTS), Adelaide, South Australia, Australia.,Department of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - P Toby H Coates
- The Centre for Clinical and Experimental Transplantation (CCET), Central Northern Adelaide Renal and Transplantation Services (CNARTS), Adelaide, South Australia, Australia.,Department of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| |
Collapse
|
27
|
De Filippo E, Namasivayam V, Zappe L, El-Tayeb A, Schiedel AC, Müller CE. Role of extracellular cysteine residues in the adenosine A2A receptor. Purinergic Signal 2016; 12:313-29. [PMID: 26969588 DOI: 10.1007/s11302-016-9506-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/29/2016] [Indexed: 12/13/2022] Open
Abstract
The G protein-coupled A2A adenosine receptor represents an important drug target. Crystal structures and modeling studies indicated that three disulfide bonds are formed between ECL1 and ECL2 (I, Cys71(2.69)-Cys159(45.43); II, Cys74(3.22)-Cys146(45.30), and III, Cys77(3.25)-Cys166(45.50)). However, the A2BAR subtype appears to require only disulfide bond III for proper function. In this study, each of the three disulfide bonds in the A2AAR was disrupted by mutation of one of the cysteine residues to serine. The mutant receptors were stably expressed in Chinese hamster ovary cells and analyzed in cyclic adenosine monophosphate (cAMP) accumulation and radioligand binding studies using structurally diverse agonists: adenosine, NECA, CGS21680, and PSB-15826. Results were rationalized by molecular modeling. The observed effects were dependent on the investigated agonist. Loss of disulfide bond I led to a widening of the orthosteric binding pocket resulting in a strong reduction in the potency of adenosine, but not of NECA or 2-substituted nucleosides. Disruption of disulfide bond II led to a significant reduction in the agonists' efficacy indicating its importance for receptor activation. Disulfide bond III disruption reduced potency and affinity of the small adenosine agonists and NECA, but not of the larger 2-substituted agonists. While all the three disulfide bonds were essential for high potency or efficacy of adenosine, structural modification of the nucleoside could rescue affinity or efficacy at the mutant receptors. At present, it cannot be excluded that formation of the extracellular disulfide bonds in the A2AAR is dynamic. This might add another level of G protein-coupled receptor (GPCR) modulation, in particular for the cysteine-rich A2A and A2BARs.
Collapse
Affiliation(s)
- Elisabetta De Filippo
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Vigneshwaran Namasivayam
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Lukas Zappe
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Ali El-Tayeb
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Anke C Schiedel
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Christa E Müller
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany.
| |
Collapse
|
28
|
Karnik SS, Unal H, Kemp JR, Tirupula KC, Eguchi S, Vanderheyden PML, Thomas WG. International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected]. Pharmacol Rev 2015; 67:754-819. [PMID: 26315714 PMCID: PMC4630565 DOI: 10.1124/pr.114.010454] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The renin angiotensin system (RAS) produced hormone peptides regulate many vital body functions. Dysfunctional signaling by receptors for RAS peptides leads to pathologic states. Nearly half of humanity today would likely benefit from modern drugs targeting these receptors. The receptors for RAS peptides consist of three G-protein-coupled receptors—the angiotensin II type 1 receptor (AT1 receptor), the angiotensin II type 2 receptor (AT2 receptor), the MAS receptor—and a type II trans-membrane zinc protein—the candidate angiotensin IV receptor (AngIV binding site). The prorenin receptor is a relatively new contender for consideration, but is not included here because the role of prorenin receptor as an independent endocrine mediator is presently unclear. The full spectrum of biologic characteristics of these receptors is still evolving, but there is evidence establishing unique roles of each receptor in cardiovascular, hemodynamic, neurologic, renal, and endothelial functions, as well as in cell proliferation, survival, matrix-cell interaction, and inflammation. Therapeutic agents targeted to these receptors are either in active use in clinical intervention of major common diseases or under evaluation for repurposing in many other disorders. Broad-spectrum influence these receptors produce in complex pathophysiological context in our body highlights their role as precise interpreters of distinctive angiotensinergic peptide cues. This review article summarizes findings published in the last 15 years on the structure, pharmacology, signaling, physiology, and disease states related to angiotensin receptors. We also discuss the challenges the pharmacologist presently faces in formally accepting newer members as established angiotensin receptors and emphasize necessary future developments.
Collapse
Affiliation(s)
- Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Jacqueline R Kemp
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Kalyan C Tirupula
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Satoru Eguchi
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Patrick M L Vanderheyden
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Walter G Thomas
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| |
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
Abstract
Many receptors display conformational flexibility, in which the binding pocket has an open inactive conformation in the absence of ligand and a tight active conformation when bound to ligand. Here we study the bacterial adhesin FimH to address the role of the inactive conformation of the pocket for initiating binding by comparing two variants: a wild-type FimH variant that is in the inactive state when not bound to its target mannose, and an engineered activated variant that is always in the active state. Not surprisingly, activated FimH has a longer lifetime and higher affinity, and bacteria expressing activated FimH bound better in static conditions. However, bacteria expressing wild-type FimH bound better in flow. Wild-type and activated FimH demonstrated similar mechanical strength, likely because mechanical force induces the active state in wild-type FimH. However, wild-type FimH displayed a faster bond association rate than activated FimH. Moreover, the ability of different FimH variants to mediate adhesion in flow reflected the fraction of FimH in the inactive state. These results demonstrate a new model for ligand-associated conformational changes that we call the kinetic-selection model, in which ligand-binding selects the faster-binding inactive state and then induces the active state. This model predicts that in physiological conditions for cell adhesion, mechanical force will drive a nonequilibrium cycle that uses the fast binding rate of the inactive state and slow unbinding rate of the active state, for a higher effective affinity than is possible at equilibrium.
Collapse
|
31
|
Takezako T, Unal H, Karnik SS, Node K. Structure-Function Basis of Attenuated Inverse Agonism of Angiotensin II Type 1 Receptor Blockers for Active-State Angiotensin II Type 1 Receptor. Mol Pharmacol 2015; 88:488-501. [PMID: 26121982 DOI: 10.1124/mol.115.099176] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/29/2015] [Indexed: 01/05/2023] Open
Abstract
Ligand-independent signaling by the angiotensin II type 1 receptor (AT1R) can be activated in clinical settings by mechanical stretch and autoantibodies as well as receptor mutations. Transition of the AT1R to the activated state is known to lower inverse agonistic efficacy of clinically used AT1R blockers (ARBs). The structure-function basis for reduced efficacy of inverse agonists is a fundamental aspect that has been understudied not only in relation to the AT1R but also regarding other homologous receptors. Here, we demonstrate that the active-state transition in the AT1R indeed attenuates an inverse agonistic effect of four biphenyl-tetrazole ARBs through changes in specific ligand-receptor interactions. In the ground state, tight interactions of four ARBs with a set of residues (Ser109(TM3), Phe182(ECL2), Gln257(TM6), Tyr292(TM7), and Asn295(TM7)) results in potent inverse agonism. In the activated state, the ARB-AT1R interactions shift to a different set of residues (Val108(TM3), Ser109(TM3), Ala163(TM4), Phe182(ECL2), Lys199(TM5), Tyr292(TM7), and Asn295(TM7)), resulting in attenuated inverse agonism. Interestingly, V108I, A163T, N295A, and F182A mutations in the activated state of the AT1R shift the functional response to the ARB binding toward agonism, but in the ground state the same mutations cause inverse agonism. Our data show that the second extracellular loop is an important regulator of the functional states of the AT1R. Our findings suggest that the quest for discovering novel ARBs, and improving current ARBs, fundamentally depends on the knowledge of the unique sets of residues that mediate inverse agonistic potency in the two states of the AT1R.
Collapse
Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Hamiyet Unal
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Sadashiva S Karnik
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Koichi Node
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| |
Collapse
|
32
|
Structure of the Angiotensin receptor revealed by serial femtosecond crystallography. Cell 2015; 161:833-44. [PMID: 25913193 DOI: 10.1016/j.cell.2015.04.011] [Citation(s) in RCA: 269] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/30/2014] [Accepted: 03/02/2015] [Indexed: 01/01/2023]
Abstract
Angiotensin II type 1 receptor (AT(1)R) is a G protein-coupled receptor that serves as a primary regulator for blood pressure maintenance. Although several anti-hypertensive drugs have been developed as AT(1)R blockers (ARBs), the structural basis for AT(1)R ligand-binding and regulation has remained elusive, mostly due to the difficulties of growing high-quality crystals for structure determination using synchrotron radiation. By applying the recently developed method of serial femtosecond crystallography at an X-ray free-electron laser, we successfully determined the room-temperature crystal structure of the human AT(1)R in complex with its selective antagonist ZD7155 at 2.9-Å resolution. The AT(1)R-ZD7155 complex structure revealed key structural features of AT(1)R and critical interactions for ZD7155 binding. Docking simulations of the clinically used ARBs into the AT(1)R structure further elucidated both the common and distinct binding modes for these anti-hypertensive drugs. Our results thereby provide fundamental insights into AT(1)R structure-function relationship and structure-based drug design.
Collapse
|
33
|
Shore DM, Reggio PH. The therapeutic potential of orphan GPCRs, GPR35 and GPR55. Front Pharmacol 2015; 6:69. [PMID: 25926795 PMCID: PMC4397721 DOI: 10.3389/fphar.2015.00069] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/15/2015] [Indexed: 12/19/2022] Open
Abstract
The G protein-coupled receptor (GPCR) superfamily of integral proteins is the largest family of signal transducers, comprised of ∼1000 members. Considering their prevalence and functional importance, it’s not surprising that ∼60% of drugs target GPCRs. Regardless, there exists a subset of the GPCR superfamily that is largely uncharacterized and poorly understood; specifically, more than 140 GPCRs have unknown endogenous ligands—the so-called orphan GPCRs. Orphan GPCRs offer tremendous promise, as they may provide novel therapeutic targets that may be more selective than currently known receptors, resulting in the potential reduction in side effects. In addition, they may provide access to signal transduction pathways currently unknown, allowing for new strategies in drug design. Regardless, orphan GPCRs are an important area of inquiry, as they represent a large gap in our understanding of signal transduction at the cellular level. Here, we focus on the therapeutic potential of two recently deorphanized GPCRs: GPR35/CXCR8 and GPR55. First, GPR35/CXCR8 has been observed in numerous tissues/organ systems, including the gastrointestinal tract, liver, immune system, central nervous system, and cardiovascular system. Not surprisingly, GPR35/CXCR8 has been implicated in numerous pathologies involving these tissues/systems. While several endogenous ligands have been identified, GPR35/CXCR8 has recently been observed to bind the chemokine CXCL17. Second, GPR55 has been observed to be expressed in the central nervous system, adrenal glands, gastrointestinal tract, lung, liver, uterus, bladder, kidney, and bone, as well as, other tissues/organ systems. Likewise, it is not surprising that GPR55 has been implicated in pathologies involving these tissues/systems. GPR55 was initially deorphanized as a cannabinoid receptor and this receptor does bind many cannabinoid compounds. However, the GPR55 endogenous ligand has been found to be a non-cannabinoid, lysophophatidylinositol (LPI) and subsequent high throughput assays have identified other GPR55 ligands that are not cannabinoids and do not bind to either the cannabinoid CB1 and CB2 receptors. Here, we review reports that suggest that GPR35/CXCR8 and GPR55 may be promising therapeutic targets, with diverse physiological roles.
Collapse
Affiliation(s)
- Derek M Shore
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina Greensboro Greensboro, NC, USA
| | - Patricia H Reggio
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina Greensboro Greensboro, NC, USA
| |
Collapse
|
34
|
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.
Collapse
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
| |
Collapse
|
35
|
The patent situation concerning the treatment of diseases associated with autoantibodies directed against G-protein-coupled receptors. Pharm Pat Anal 2014; 2:231-48. [PMID: 24237028 DOI: 10.4155/ppa.12.88] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Agonist-like autoantibodies against receptors of the G-protein-coupled signal cascade have been identified as the pathogenic principle for a variety of diseases, especially those of the heart and vascular system. Consequently, the elimination or neutralization of such autoantibodies is an advised goal for causal therapeutic intervention. This article provides a short, noncomplete overview about remarkable developmental strategies and technical solutions for the therapy of diseases, associated with G-protein-coupled receptor autoantibodies. According to the immunoglobulin nature of the therapeutic target, several strategies are possible, such as the use of the autoantibody epitope sequences as competitors or binding molecules for specific autoantibody-elimination by apheresis. Complete immunoglobulin elimination, as is currently being tested in autoantibody-positive cardiomyopathy patients, would be a nonspecific solution as would the use of immunosuppressant agents. The use of autoantibody-binding molecules on an aptamer basis for neutralization or elimination is a newly developed specific therapeutic option.
Collapse
|
36
|
Agonistic autoantibodies directed against G-protein-coupled receptors and their relationship to cardiovascular diseases. Semin Immunopathol 2014; 36:351-63. [PMID: 24777744 DOI: 10.1007/s00281-014-0425-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/01/2014] [Indexed: 02/06/2023]
Abstract
Agonistic autoantibodies (AABs) against G-protein-coupled receptor (GPCR) are present mainly in diseases of the cardiovascular system or in diseases associated with cardiovascular disturbances. The increasing knowledge about the role of autoantibodies against G-protein-coupled receptor (GPCR-AABs) as pathogenic drivers, the resulting development of strategies aimed at their removal or neutralization, and the evidenced patient benefit associated with such therapies have created the need for a summary of GPCR-AAB-associated diseases. Here, we summarize the present knowledge about GPCR-AABs in cardiovascular diseases. The identity of the GPCR-AABs and their prevalence in each of several specific cardiovascular diseases are documented. The structure of GPCR is also briefly discussed. Using this information, differences between classic agonists and GPCR-AABs in their GPCR binding and activation are presented and the resulting pathogenic consequences are discussed. Furthermore, treatment strategies that are currently under study, most of which are aimed at the removal and in vivo neutralization of GPCR-AABs, are indicated and their patient benefits discussed. In this context, immunoadsorption using peptides/proteins or aptamers as binders are introduced. The use of peptides or aptamers for in vivo neutralization of GPCR-AABs is also described. Particular attention is given to the GPCR-AABs directed against the adrenergic beta1-, beta2-, and α1-receptor as well as the muscarinic receptor M2, angiotensin II-angiotensin receptor type I, endothelin1 receptor type A, angiotensin (1-7) Mas-receptor, and 5-hydroxytryptamine receptor 4. Among the diseases associated with GPCR-AABs, special focus is given to idiopathic dilated cardiomyopathy, Chagas' cardiomyopathy, malignant and pulmonary hypertension, and kidney diseases. Relationships of GPCR-AABs are indicated to glaucoma, peripartum cardiomyopathy, myocarditis, pericarditis, preeclampsia, Alzheimer's disease, Sjörgren's syndrome, and metabolic syndrome after cancer chemotherapy.
Collapse
|
37
|
Unal H, Karnik SS. Constitutive activity in the angiotensin II type 1 receptor: discovery and applications. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 70:155-74. [PMID: 24931196 DOI: 10.1016/b978-0-12-417197-8.00006-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The pathophysiological actions of the renin-angiotensin system hormone, angiotensin II (AngII), are mainly mediated by the AngII type 1 (AT1) receptor, a GPCR. The intrinsic spontaneous activity of the AT1 receptor in native tissues is difficult to detect due to its low expression levels. However, factors such as the membrane environment, interaction with autoantibodies, and mechanical stretch are known to increase G protein signaling in the absence of AngII. Naturally occurring and disease-causing activating mutations have not been identified in AT1 receptor. Constitutively active mutants (CAMs) of AT1 receptor have been engineered using molecular modeling and site-directed mutagenesis approaches among which substitution of Asn(111) in the transmembrane helix III with glycine or serine results in the highest basal activity of the receptor. Transgenic animal models expressing the CAM AT1 receptors that mimic various in vivo disease conditions have been useful research tools for discovering the pathophysiological role of AT1 receptor and evaluating the therapeutic potential of inverse agonists. This chapter summarizes the studies on the constitutive activity of AT1 receptor in recombinant as well as physiological systems. The impact of the availability of CAM AT1 receptors on our understanding of the molecular mechanisms underlying receptor activation and inverse agonism is described.
Collapse
Affiliation(s)
- Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
| |
Collapse
|
38
|
Shore DM, Baillie GL, Hurst DH, Navas F, Seltzman HH, Marcu JP, Abood ME, Ross RA, Reggio PH. Allosteric modulation of a cannabinoid G protein-coupled receptor: binding site elucidation and relationship to G protein signaling. J Biol Chem 2013; 289:5828-45. [PMID: 24366865 DOI: 10.1074/jbc.m113.478495] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cannabinoid 1 (CB1) allosteric modulator, 5-chloro-3-ethyl-1H-indole-2-carboxylic acid [2-(4-piperidin-1-yl-phenyl)-ethyl]-amide) (ORG27569), has the paradoxical effect of increasing the equilibrium binding of [(3)H](-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)phenyl]-4-[3-hydroxylpropyl]cyclohexan-1-ol (CP55,940, an orthosteric agonist) while at the same time decreasing its efficacy (in G protein-mediated signaling). ORG27569 also decreases basal signaling, acting as an inverse agonist for the G protein-mediated signaling pathway. In ligand displacement assays, ORG27569 can displace the CB1 antagonist/inverse agonist, N-(piperidiny-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide(SR141716A). The goal of this work was to identify the binding site of ORG27569 at CB1. To this end, we used computation, synthesis, mutation, and functional studies to identify the ORG27569-binding site in the CB1 TMH3-6-7 region. This site is consistent with the results of K3.28(192)A, F3.36(200)A, W5.43(279)A, W6.48(356)A, and F3.25(189)A mutation studies, which revealed the ORG27569-binding site overlaps with our previously determined binding site of SR141716A but extends extracellularly. Additionally, we identified a key electrostatic interaction between the ORG27569 piperidine ring nitrogen and K3.28(192) that is important for ORG27569 to act as an inverse agonist. At this allosteric site, ORG27569 promotes an intermediate conformation of the CB1 receptor, explaining ORG27569's ability to increase equilibrium binding of CP55,940. This site also explains ORG27569's ability to antagonize the efficacy of CP55,940 in three complementary ways. 1) ORG27569 sterically blocks movements of the second extracellular loop that have been linked to receptor activation. 2) ORG27569 sterically blocks a key electrostatic interaction between the third extracellular loop residue Lys-373 and D2.63(176). 3) ORG27569 packs against TMH6, sterically hindering movements of this helix that have been shown to be important for receptor activation.
Collapse
Affiliation(s)
- Derek M Shore
- From the Center for Drug Discovery, University of North Carolina at Greensboro, Greensboro, North Carolina 27402
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Kotsikorou E, Sharir H, Shore DM, Hurst DP, Lynch DL, Madrigal KE, Heynen-Genel S, Milan LB, Chung TDY, Seltzman HH, Bai Y, Caron MG, Barak LS, Croatt MP, Abood ME, Reggio PH. Identification of the GPR55 antagonist binding site using a novel set of high-potency GPR55 selective ligands. Biochemistry 2013; 52:9456-69. [PMID: 24274581 DOI: 10.1021/bi4008885] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
GPR55 is a class A G protein-coupled receptor (GPCR) that has been implicated in inflammatory pain, neuropathic pain, metabolic disorder, bone development, and cancer. Initially deorphanized as a cannabinoid receptor, GPR55 has been shown to be activated by non-cannabinoid ligands such as l-α-lysophosphatidylinositol (LPI). While there is a growing body of evidence of physiological and pathophysiological roles for GPR55, the paucity of specific antagonists has limited its study. In collaboration with the Molecular Libraries Probe Production Centers Network initiative, we identified a series of GPR55 antagonists using a β-arrestin, high-throughput, high-content screen of ~300000 compounds. This screen yielded novel, GPR55 antagonist chemotypes with IC50 values in the range of 0.16-2.72 μM [Heynen-Genel, S., et al. (2010) Screening for Selective Ligands for GPR55: Antagonists (ML191, ML192, ML193) (Bookshelf ID NBK66153; PMID entry 22091481)]. Importantly, many of the GPR55 antagonists were completely selective, with no agonism or antagonism against GPR35, CB1, or CB2 up to 20 μM. Using a model of the GPR55 inactive state, we studied the binding of an antagonist series that emerged from this screen. These studies suggest that GPR55 antagonists possess a head region that occupies a horizontal binding pocket extending into the extracellular loop region, a central ligand portion that fits vertically in the receptor binding pocket and terminates with a pendant aromatic or heterocyclic ring that juts out. Both the region that extends extracellularly and the pendant ring are features associated with antagonism. Taken together, our results provide a set of design rules for the development of second-generation GPR55 selective antagonists.
Collapse
Affiliation(s)
- Evangelia Kotsikorou
- Department of Chemistry, University of Texas-Pan American , Edinburg, Texas 78539, United States
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Reassessment of the unique mode of binding between angiotensin II type 1 receptor and their blockers. PLoS One 2013; 8:e79914. [PMID: 24260317 PMCID: PMC3832659 DOI: 10.1371/journal.pone.0079914] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 09/25/2013] [Indexed: 11/30/2022] Open
Abstract
While the molecular structures of angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) are very similar, they are also slightly different. Although each ARB has been shown to exhibit a unique mode of binding to AT1 receptor, different positions of the AT1 receptor have been analyzed and computational modeling has been performed using different crystal structures for the receptor as a template and different kinds of software. Therefore, we systematically analyzed the critical positions of the AT1 receptor, Tyr113, Tyr184, Lys199, His256 and Gln257 using a mutagenesis study, and subsequently performed computational modeling of the binding of ARBs to AT1 receptor using CXCR4 receptor as a new template and a single version of software. The interactions between Tyr113 in the AT1 receptor and the hydroxyl group of olmesartan, between Lys199 and carboxyl or tetrazole groups, and between His256 or Gln257 and the tetrazole group were studied. The common structure, a tetrazole group, of most ARBs similarly bind to Lys199, His256 and Gln257 of AT1 receptor. Lys199 in the AT1 receptor binds to the carboxyl group of EXP3174, candesartan and azilsartan, whereas oxygen in the amidecarbonyl group of valsartan may bind to Lys199. The benzimidazole portion of telmisartan may bind to a lipophilic pocket that includes Tyr113. On the other hand, the n-butyl group of irbesartan may bind to Tyr113. In conclusion, we confirmed that the slightly different structures of ARBs may be critical for binding to AT1 receptor and for the formation of unique modes of binding.
Collapse
|
41
|
Matsoukas MT, Cordomí A, Ríos S, Pardo L, Tselios T. Ligand binding determinants for angiotensin II type 1 receptor from computer simulations. J Chem Inf Model 2013; 53:2874-83. [PMID: 24090110 DOI: 10.1021/ci400400m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ligand binding determinants for the angiotensin II type 1 receptor (AT1R), a G protein-coupled receptor (GPCR), have been characterized by means of computer simulations. As a first step, a pharmacophore model of various known AT1R ligands exhibiting a wide range of binding affinities was generated. Second, a structural model of AT1R was built making use of the growing set of crystal structures of GPCRs, which was further used for the docking of the AT1R ligands based on the devised pharmacophore model. Next, ligand-receptor-lipid bilayer systems were studied by means of molecular dynamics (MD) simulations. Overall, the present study has permitted, combining the pharmacophore model with binding free energy calculations obtained from the MD simulations, to propose the molecular mechanisms by which sartans interact with AT1R.
Collapse
|
42
|
Gil-Mast S, Kortagere S, Kota K, Kuzhikandathil EV. An amino acid residue in the second extracellular loop determines the agonist-dependent tolerance property of the human D3 dopamine receptor. ACS Chem Neurosci 2013; 4:940-51. [PMID: 23477444 DOI: 10.1021/cn3002202] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The D3 dopamine receptor is a therapeutic target for treating various nervous system disorders such as schizophrenia, Parkinson's disease, depression, and addictive behaviors. The crystal structure of the D3 receptor bound to an antagonist was recently described; however, the structural features that contribute to agonist-induced conformational changes and signaling properties are not well understood. We have previously described the conformation-dependent tolerance and slow response termination (SRT) signaling properties of the D3 receptor and identified the C147 residue in the second intracellular loop (IL2) of the D3 receptor as important for the tolerance property. Interestingly, while IL2 and the C147 residue, in particular, were important for dopamine- and quinpirole-induced tolerance, this residue did not affect the severe tolerance induced by the high affinity, D3 receptor-selective agonist, PD128907. Here, we used D2/D3 receptor chimeras and site-specific D3 receptor mutants to identify another residue, D187, in the second extracellular loop (EC2) of the human D3 receptor that mediates the tolerance property induced by PD128907, quinpirole, pramipexole, and dopamine. Molecular dynamics simulations confirmed the distinct conformation adopted by D3 receptor during tolerance and suggested that in the tolerant D3 receptor the D187 residue in EC2 forms a salt bridge with the H354 residue in EC3. Indeed, site-directed mutation of the H354 residue resulted in loss of PD1287907-induced tolerance. The mapping of specific amino acid residues that contribute to agonist-dependent conformation changes and D3 receptor signaling properties refines the agonist-bound D3 receptor pharmacophore model which will help develop novel D3 receptor agonists.
Collapse
Affiliation(s)
- Sara Gil-Mast
- Department of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, New Jersey
07103, United States
| | - Sandhya Kortagere
- Department
of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, United
States
| | - Kokila Kota
- Department of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, New Jersey
07103, United States
| | - Eldo V. Kuzhikandathil
- Department of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, New Jersey
07103, United States
| |
Collapse
|
43
|
Greives N, Zhou HX. BDflex: a method for efficient treatment of molecular flexibility in calculating protein-ligand binding rate constants from brownian dynamics simulations. J Chem Phys 2013; 137:135105. [PMID: 23039617 DOI: 10.1063/1.4756913] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A method developed by Northrup et al. [J. Chem. Phys. 80, 1517 (1984)] for calculating protein-ligand binding rate constants (k(a)) from brownian dynamics (BD) simulations has been widely used for rigid molecules. Application to flexible molecules is limited by the formidable computational cost to treat conformational fluctuations during the long BD simulations necessary for k(a) calculation. Here, we propose a new method called BDflex for k(a) calculation that circumvents this problem. The basic idea is to separate the whole space into an outer region and an inner region, and formulate k(a) as the product of k(E) and η(d), which are obtained by separately solving exterior and interior problems. k(E) is the diffusion-controlled rate constant for the ligand in the outer region to reach the dividing surface between the outer and inner regions; in this exterior problem conformational fluctuations can be neglected. η(d) is the probability that the ligand, starting from the dividing surface, will react at the binding site rather than escape to infinity. The crucial step in reducing the determination of η(d) to a problem confined to the inner region is a radiation boundary condition imposed on the dividing surface; the reactivity on this boundary is proportional to k(E). By confining the ligand to the inner region and imposing the radiation boundary condition, we avoid multiple-crossing of the dividing surface before reaction at the binding site and hence dramatically cut down the total simulation time, making the treatment of conformational fluctuations affordable. BDflex is expected to have wide applications in problems where conformational fluctuations of the molecules are crucial for productive ligand binding, such as in cases where transient widening of a bottleneck allows the ligand to access the binding pocket, or the binding site is properly formed only after ligand entrance induces the closure of a lid.
Collapse
Affiliation(s)
- Nicholas Greives
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA
| | | |
Collapse
|
44
|
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.
Collapse
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.
| |
Collapse
|
45
|
Chen X, Qiu Z, Yang S, Ding D, Chen F, Zhou Y, Wang M, Lin J, Yu X, Zhou Z, Liao Y. Effectiveness and Safety of a Therapeutic Vaccine Against Angiotensin II Receptor Type 1 in Hypertensive Animals. Hypertension 2013. [DOI: 10.1161/hypertensionaha.112.201020] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xiao Chen
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Zhihua Qiu
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Shijun Yang
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Dan Ding
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Fen Chen
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yanzhao Zhou
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Min Wang
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jibin Lin
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Xian Yu
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Zihua Zhou
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yuhua Liao
- From the Laboratory of Cardiovascular Immunology, Key Laboratory of Molecular Targeted Therapies of the Ministry of Education, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
46
|
Dragun D, Catar R, Kusch A, Heidecke H, Philippe A. Non-HLA-antibodies targeting Angiotensin type 1 receptor and antibody mediated rejection. Hum Immunol 2012; 73:1282-6. [DOI: 10.1016/j.humimm.2012.07.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/14/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022]
|
47
|
Unal H, Jagannathan R, Bhatnagar A, Tirupula K, Desnoyer R, Karnik SS. Long range effect of mutations on specific conformational changes in the extracellular loop 2 of angiotensin II type 1 receptor. J Biol Chem 2012; 288:540-51. [PMID: 23139413 DOI: 10.1074/jbc.m112.392514] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The topology of the second extracellular loop (ECL2) and its interaction with ligands is unique in each G protein-coupled receptor. When the orthosteric ligand pocket located in the transmembrane (TM) domain is occupied, ligand-specific conformational changes occur in the ECL2. In more than 90% of G protein-coupled receptors, ECL2 is tethered to the third TM helix via a disulfide bond. Therefore, understanding the extent to which the TM domain and ECL2 conformations are coupled is useful. To investigate this, we examined conformational changes in ECL2 of the angiotensin II type 1 receptor (AT1R) by introducing mutations in distant sites that alter the activation state equilibrium of the AT1R. Differential accessibility of reporter cysteines introduced at four conformation-sensitive sites in ECL2 of these mutants was measured. Binding of the agonist angiotensin II (AngII) and inverse agonist losartan in wild-type AT1R changed the accessibility of reporter cysteines, and the pattern was consistent with ligand-specific "lid" conformations of ECL2. Without agonist stimulation, the ECL2 in the gain of function mutant N111G assumed a lid conformation similar to AngII-bound wild-type AT1R. In the presence of inverse agonists, the conformation of ECL2 in the N111G mutant was similar to the inactive state of wild-type AT1R. In contrast, AngII did not induce a lid conformation in ECL2 in the loss of function D281A mutant, which is consistent with the reduced AngII binding affinity in this mutant. However, a lid conformation was induced by [Sar(1),Gln(2),Ile(8)] AngII, a specific analog that binds to the D281A mutant with better affinity than AngII. These results provide evidence for the emerging paradigm of domain coupling facilitated by long range interactions at distant sites on the same receptor.
Collapse
Affiliation(s)
- Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | | | | | | | | | | |
Collapse
|
48
|
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: 224] [Impact Index Per Article: 18.7] [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.
Collapse
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
| |
Collapse
|
49
|
Eilers M, Goncalves JA, Ahuja S, Kirkup C, Hirshfeld A, Simmerling C, Reeves PJ, Sheves M, Smith SO. Structural transitions of transmembrane helix 6 in the formation of metarhodopsin I. J Phys Chem B 2012; 116:10477-89. [PMID: 22564141 DOI: 10.1021/jp3019183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Absorption of light by the visual pigment rhodopsin triggers a rapid cis-trans photoisomerization of its retinal chromophore and a series of conformational changes in both the retinal and protein. The largest structural change is an outward tilt of transmembrane helix H6 that increases the separation of the intracellular ends of H6 and H3 and opens up the G-protein binding site. In the dark state of rhodopsin, Glu247 at the intracellular end of H6 forms a salt bridge with Arg135 on H3 to tether H6 in an inactive conformation. The Arg135-Glu247 interaction is broken in the active state of the receptor, and Arg135 is then stabilized by interactions with Tyr223, Met257, and Tyr306 on helices H5, H6, and H7, respectively. To address the mechanism of H6 motion, solid-state NMR measurements are undertaken of Metarhodopsin I (Meta I), the intermediate preceding the active Metarhodopsin II (Meta II) state of the receptor. (13)C NMR dipolar recoupling measurements reveal an interhelical contact of (13)Cζ-Arg135 with (13)Cε-Met257 in Meta I but not with (13)Cζ-Tyr223 or (13)Cζ-Tyr306. These observations suggest that helix H6 has rotated in the formation of Meta I but that structural changes involving helices H5 and H7 have not yet occurred. Together, our results provide insights into the sequence of events leading up to the outward motion of H6, a hallmark of G protein-coupled receptor activation.
Collapse
Affiliation(s)
- Markus Eilers
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Unal H, Jagannathan R, Karnik SS. Mechanism of GPCR-Directed Autoantibodies in Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 749:187-99. [DOI: 10.1007/978-1-4614-3381-1_13] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|