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Dale NC, Hoyer D, Jacobson LH, Pfleger KDG, Johnstone EKM. Orexin Signaling: A Complex, Multifaceted Process. Front Cell Neurosci 2022; 16:812359. [PMID: 35496914 PMCID: PMC9044999 DOI: 10.3389/fncel.2022.812359] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/07/2022] [Indexed: 11/15/2022] Open
Abstract
The orexin system comprises two G protein-coupled receptors, OX1 and OX2 receptors (OX1R and OX2R, respectively), along with two endogenous agonists cleaved from a common precursor (prepro-orexin), orexin-A (OX-A) and orexin-B (OX-B). For the receptors, a complex array of signaling behaviors has been reported. In particular, it becomes obvious that orexin receptor coupling is very diverse and can be tissue-, cell- and context-dependent. Here, the early signal transduction interactions of the orexin receptors will be discussed in depth, with particular emphasis on the direct G protein interactions of each receptor. In doing so, it is evident that ligands, additional receptor-protein interactions and cellular environment all play important roles in the G protein coupling profiles of the orexin receptors. This has potential implications for our understanding of the orexin system’s function in vivo in both central and peripheral environments, as well as the development of novel agonists, antagonists and possibly allosteric modulators targeting the orexin system.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Laura H. Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Kevin D. G. Pfleger,
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- Elizabeth K. M. Johnstone,
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Dale NC, Johnstone EKM, Pfleger KDG. GPCR heteromers: An overview of their classification, function and physiological relevance. Front Endocrinol (Lausanne) 2022; 13:931573. [PMID: 36111299 PMCID: PMC9468249 DOI: 10.3389/fendo.2022.931573] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/08/2022] [Indexed: 11/25/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are capable of interacting to form higher order structures such as homomers and heteromers. Heteromerisation in particular has implications for receptor function, with research showing receptors can attain unique expression, ligand binding, signalling and intracellular trafficking upon heteromerisation. As such, GPCR heteromers represent novel drug targets with extensive therapeutic potential. Changes to ligand affinity, efficacy and G protein coupling have all been described, with alterations to these pharmacological aspects now well accepted as common traits for heteromeric complexes. Changes in internalisation and trafficking kinetics, as well as β-arrestin interactions are also becoming more apparent, however, few studies to date have explicitly looked at the implications these factors have upon the signalling profile of a heteromer. Development of ligands to target GPCR heteromers both experimentally and therapeutically has been mostly concentrated on bivalent ligands due to difficulties in identifying and developing heteromer-specific ligands. Improving our understanding of the pharmacology and physiology of GPCR heteromers will enable further development of heteromer-specific ligands with potential to provide therapeutics with increased efficacy and decreased side effects.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- *Correspondence: Kevin D. G. Pfleger, ; Elizabeth K. M. Johnstone,
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, Australia
- *Correspondence: Kevin D. G. Pfleger, ; Elizabeth K. M. Johnstone,
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Johnstone EKM, Ayoub MA, Hertzman RJ, See HB, Abhayawardana RS, Seeber RM, Pfleger KDG. Novel Pharmacology Following Heteromerization of the Angiotensin II Type 2 Receptor and the Bradykinin Type 2 Receptor. Front Endocrinol (Lausanne) 2022; 13:848816. [PMID: 35721749 PMCID: PMC9204302 DOI: 10.3389/fendo.2022.848816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/21/2022] [Indexed: 01/18/2023] Open
Abstract
The angiotensin type 2 (AT2) receptor and the bradykinin type 2 (B2) receptor are G protein-coupled receptors (GPCRs) that have major roles in the cardiovascular system. The two receptors are known to functionally interact at various levels, and there is some evidence that the observed crosstalk may occur as a result of heteromerization. We investigated evidence for heteromerization of the AT2 receptor and the B2 receptor in HEK293FT cells using various bioluminescence resonance energy transfer (BRET)-proximity based assays, including the Receptor Heteromer Investigation Technology (Receptor-HIT) and the NanoBRET ligand-binding assay. The Receptor-HIT assay showed that Gαq, GRK2 and β-arrestin2 recruitment proximal to AT2 receptors only occurred upon B2 receptor coexpression and activation, all of which is indicative of AT2-B2 receptor heteromerization. Additionally, we also observed specific coupling of the B2 receptor with the Gαz protein, and this was found only in cells coexpressing both receptors and stimulated with bradykinin. The recruitment of Gαz, Gαq, GRK2 and β-arrestin2 was inhibited by B2 receptor but not AT2 receptor antagonism, indicating the importance of B2 receptor activation within AT2-B2 heteromers. The close proximity between the AT2 receptor and B2 receptor at the cell surface was also demonstrated with the NanoBRET ligand-binding assay. Together, our data demonstrate functional interaction between the AT2 receptor and B2 receptor in HEK293FT cells, resulting in novel pharmacology for both receptors with regard to Gαq/GRK2/β-arrestin2 recruitment (AT2 receptor) and Gαz protein coupling (B2 receptor). Our study has revealed a new mechanism for the enigmatic and poorly characterized AT2 receptor to be functionally active within cells, further illustrating the role of heteromerization in the diversity of GPCR pharmacology and signaling.
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
| | - Mohammed Akli Ayoub
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Rebecca J. Hertzman
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Heng B. See
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Rekhati S. Abhayawardana
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Ruth M. Seeber
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Kevin D. G. Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
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O'Brien SL, Johnstone EKM, Devost D, Conroy J, Reichelt ME, Purdue BW, Ayoub MA, Kawai T, Inoue A, Eguchi S, Hébert TE, Pfleger KDG, Thomas WG. Corrigendum to "BRET-based assay to monitor EGFR transactivation by the AT1R reveals Gq/11 protein-independent activation and AT1R-EGFR complexes" [Biochem. Pharmacol. 158 (2108) 232-242]. Biochem Pharmacol 2021; 192:114756. [PMID: 34509100 DOI: 10.1016/j.bcp.2021.114756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jacinta Conroy
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Melissa E Reichelt
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Brooke W Purdue
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Mohammed A Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tatsuo Kawai
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Satoru Eguchi
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Centre for Cardiac and Vasculature Biology, The University of Queensland, St Lucia 4072, Queensland, Australia.
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Johnstone EKM, Abhayawardana RS, See HB, Seeber RM, O'Brien SL, Thomas WG, Pfleger KDG. Complex interactions between the angiotensin II type 1 receptor, the epidermal growth factor receptor and TRIO-dependent signaling partners. Biochem Pharmacol 2021; 188:114521. [PMID: 33741329 DOI: 10.1016/j.bcp.2021.114521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 12/13/2022]
Abstract
Transactivation of the epidermal growth factor receptor (EGFR) by the angiotensin II (AngII) type 1 (AT1) receptor is involved in AT1 receptor-dependent growth effects and cardiovascular pathologies, however the mechanisms underpinning this transactivation are yet to be fully elucidated. Recently, a potential intermediate of this process was identified following the discovery that a kinase called TRIO was involved in AngII/AT1 receptor-mediated transactivation of EGFR. To investigate the mechanisms by which TRIO acts as an intermediate in AngII/AT1 receptor-mediated EGFR transactivation we used bioluminescence resonance energy transfer (BRET) assays to investigate proximity between the AT1 receptor, EGFR, TRIO and other proteins of interest. We found that AngII/AT1 receptor activation caused a Gαq-dependent increase in proximity of TRIO with Gγ2 and the AT1-EGFR heteromer, as well as trafficking of TRIO towards the Kras plasma membrane marker and into early, late and recycling endosomes. In contrast, we found that AngII/AT1 receptor activation caused a Gαq-independent increase in proximity of TRIO with Grb2, GRK2 and PKCζ, as well as trafficking of TRIO up to the plasma membrane from the Golgi. Furthermore, we confirmed the proximity between the AT1 receptor and the EGFR using the Receptor-Heteromer Investigation Technology, which showed AngII-induced recruitment of Grb2, GRK2, PKCζ, Gγ2 and TRIO to the EGFR upon AT1 coexpression. In summary, our results provide further evidence for the existence of the AT1-EGFR heteromer and reveal potential mechanisms by which TRIO contributes to the transactivation process.
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Affiliation(s)
- Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia.
| | - Rekhati S Abhayawardana
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Heng B See
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Ruth M Seeber
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia.
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Johnstone EKM, See HB, Abhayawardana RS, Song A, Rosengren KJ, Hill SJ, Pfleger KDG. Investigation of Receptor Heteromers Using NanoBRET Ligand Binding. Int J Mol Sci 2021; 22:1082. [PMID: 33499147 PMCID: PMC7866079 DOI: 10.3390/ijms22031082] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/20/2022] Open
Abstract
Receptor heteromerization is the formation of a complex involving at least two different receptors with pharmacology that is distinct from that exhibited by its constituent receptor units. Detection of these complexes and monitoring their pharmacology is crucial for understanding how receptors function. The Receptor-Heteromer Investigation Technology (Receptor-HIT) utilizes ligand-dependent modulation of interactions between receptors and specific biomolecules for the detection and profiling of heteromer complexes. Previously, the interacting biomolecules used in Receptor-HIT assays have been intracellular proteins, however in this study we have for the first time used bioluminescence resonance energy transfer (BRET) with fluorescently-labeled ligands to investigate heteromerization of receptors on the cell surface. Using the Receptor-HIT ligand binding assay with NanoBRET, we have successfully investigated heteromers between the angiotensin II type 1 (AT1) receptor and the β2 adrenergic receptor (AT1-β2AR heteromer), as well as between the AT1 and angiotensin II type 2 receptor (AT1-AT2 heteromer).
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Heng B. See
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Rekhati S. Abhayawardana
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Angela Song
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD 4072, Australia; (A.S.); (K.J.R.)
| | - K. Johan Rosengren
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD 4072, Australia; (A.S.); (K.J.R.)
| | - Stephen J. Hill
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, UK
- Centre of Membrane Proteins and Receptors, University of Nottingham, Midlands NG7 2UH, UK
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
- Dimerix Limited, Nedlands, WA 6009, Australia
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Chow BSM, Kocan M, Shen M, Wang Y, Han L, Chew JY, Wang C, Bosnyak S, Mirabito-Colafella KM, Barsha G, Wigg B, Johnstone EKM, Hossain MA, Pfleger KDG, Denton KM, Widdop RE, Summers RJ, Bathgate RAD, Hewitson TD, Samuel CS. AT1R-AT2R-RXFP1 Functional Crosstalk in Myofibroblasts: Impact on the Therapeutic Targeting of Renal and Cardiac Fibrosis. J Am Soc Nephrol 2019; 30:2191-2207. [PMID: 31511361 DOI: 10.1681/asn.2019060597] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/29/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Recombinant human relaxin-2 (serelaxin), which has organ-protective actions mediated via its cognate G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), has emerged as a potential agent to treat fibrosis. Studies have shown that serelaxin requires the angiotensin II (AngII) type 2 receptor (AT2R) to ameliorate renal fibrogenesis in vitro and in vivo. Whether its antifibrotic actions are affected by modulation of the AngII type 1 receptor (AT1R), which is expressed on myofibroblasts along with RXFP1 and AT2R, is unknown. METHODS We examined the signal transduction mechanisms of serelaxin when applied to primary rat renal and human cardiac myofibroblasts in vitro, and in three models of renal- or cardiomyopathy-induced fibrosis in vivo. RESULTS The AT1R blockers irbesartan and candesartan abrogated antifibrotic signal transduction of serelaxin via RXFP1 in vitro and in vivo. Candesartan also ameliorated serelaxin's antifibrotic actions in the left ventricle of mice with cardiomyopathy, indicating that candesartan's inhibitory effects were not confined to the kidney. We also demonstrated in a transfected cell system that serelaxin did not directly bind to AT1Rs but that constitutive AT1R-RXFP1 interactions could form. To potentially explain these findings, we also demonstrated that renal and cardiac myofibroblasts expressed all three receptors and that antagonists acting at each receptor directly or allosterically blocked the antifibrotic effects of either serelaxin or an AT2R agonist (compound 21). CONCLUSIONS These findings have significant implications for the concomitant use of RXFP1 or AT2R agonists with AT1R blockers, and suggest that functional interactions between the three receptors on myofibroblasts may represent new targets for controlling fibrosis progression.
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Affiliation(s)
- Bryna S M Chow
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Martina Kocan
- Florey Institute of Neuroscience and Mental Health.,Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Matthew Shen
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Yan Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Lei Han
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Jacqueline Y Chew
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Chao Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Sanja Bosnyak
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Katrina M Mirabito-Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Giannie Barsha
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Belinda Wigg
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Elizabeth K M Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | | | - Kevin D G Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia.,Department of Pharmacology and Therapeutics, ARC Centre for Personalised Therapeutic Technologies, Melbourne, Australia; and.,Dimerix Limited, Nedlands, Western Australia, Australia
| | - Kate M Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Robert E Widdop
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Ross A D Bathgate
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Chrishan S Samuel
- Department of Biochemistry and Molecular Biology, and .,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
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Abstract
Bioluminescence resonance energy transfer (BRET) is a biophysical technique used to monitor proximity within live cells. BRET exploits the naturally occurring phenomenon of dipole-dipole energy transfer from a donor enzyme (luciferase) to an acceptor fluorophore following enzyme-mediated oxidation of a substrate. This results in production of a quantifiable signal that denotes proximity between proteins and/or molecules tagged with complementary luciferase and fluorophore partners. BRET assays have been used to observe an array of biological functions including ligand binding, intracellular signaling, receptor-receptor proximity, and receptor trafficking, however, BRET assays can theoretically be used to monitor the proximity of any protein or molecule for which appropriate fusion constructs and/or fluorophore conjugates can be produced. Over the years, new luciferases and approaches have been developed that have increased the potential applications for BRET assays. In particular, the development of the small, bright and stable Nanoluciferase (NanoLuc; Nluc) and its use in NanoBRET has vastly broadened the potential applications of BRET assays. These advances have exciting potential to produce new experimental methods to monitor protein-protein interactions (PPIs), protein-ligand interactions, and/or molecular proximity. In addition to NanoBRET, Nluc has also been exploited to produce NanoBiT technology, which further broadens the scope of BRET to monitor biological function when NanoBiT is combined with an acceptor. BRET has proved to be a powerful tool for monitoring proximity and interaction, and these recent advances further strengthen its utility for a range of applications.
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Affiliation(s)
- Natasha C Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia.,Dimerix Limited, Nedlands, WA, Australia
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White CW, Johnstone EKM, See HB, Pfleger KDG. NanoBRET ligand binding at a GPCR under endogenous promotion facilitated by CRISPR/Cas9 genome editing. Cell Signal 2018; 54:27-34. [PMID: 30471466 DOI: 10.1016/j.cellsig.2018.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/10/2018] [Accepted: 11/20/2018] [Indexed: 01/14/2023]
Abstract
Bioluminescence resonance energy transfer (BRET) is a versatile tool used to investigate membrane receptor signalling and function. We have recently developed a homogenous NanoBRET ligand binding assay to monitor interactions between G protein-coupled receptors and fluorescent ligands. However, this assay requires the exogenous expression of a receptor fused to the nanoluciferase (Nluc) and is thus not applicable to natively-expressed receptors. To overcome this limitation in HEK293 cells, we have utilised CRISPR/Cas9 genome engineering to insert Nluc in-frame with the endogenous ADORA2B locus this resulted in HEK293 cells expressing adenosine A2B receptors under endogenous promotion tagged on their N-terminus with Nluc. As expected, we found relatively low levels of endogenous (gene-edited) Nluc/A2B receptor expression compared to cells transiently transfected with expression vectors coding for Nluc/A2B. However, in cells expressing gene-edited Nluc/A2B receptors we observed clear saturable ligand binding of a non-specific fluorescent adenosine receptor antagonist XAC-X-BY630 (Kd = 21.4 nM). Additionally, at gene-edited Nluc/A2B receptors we derived pharmacological parameters of ligand binding; Kd as well as Kon and Koff for binding of XAC-X-BY630 by NanoBRET association kinetic binding assays. Lastly, cells expressing gene-edited Nluc/A2B were used to determine the pKi of unlabelled adenosine receptor ligands in competition ligand binding assays. Utilising CRISPR/Cas9 genome engineering here we show that NanoBRET ligand binding assays can be performed at gene-edited receptors under endogenous promotion in live cells, therefore overcoming a fundamental limitation of NanoBRET ligand assays.
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Affiliation(s)
- Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia.
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Heng B See
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia.
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O'Brien SL, Johnstone EKM, Devost D, Conroy J, Reichelt ME, Purdue BW, Ayoub MA, Kawai T, Inoue A, Eguchi S, Hébert TE, Pfleger KDG, Thomas WG. BRET-based assay to monitor EGFR transactivation by the AT 1R reveals G q/11 protein-independent activation and AT 1R-EGFR complexes. Biochem Pharmacol 2018; 158:232-242. [PMID: 30347205 DOI: 10.1016/j.bcp.2018.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023]
Abstract
The type 1 angiotensin II (AngII) receptor (AT1R) transactivates the epidermal growth factor receptor (EGFR), which leads to pathological remodeling of heart, blood vessels and kidney. End-point assays are used as surrogates of EGFR activation, however these downstream readouts are not applicable to live cells, in real-time. Herein, we report the use of a bioluminescence resonance energy transfer (BRET)-based assay to assess recruitment of the EGFR adaptor protein, growth factor receptor-bound protein 2 (Grb2), to the EGFR. In a variety of cell lines, both epidermal growth factor (EGF) and AngII stimulated Grb2 recruitment to EGFR. The BRET assay was used to screen a panel of 9 G protein-coupled receptors (GPCRs) and further developed for other EGFR family members (HER2 and HER3); the AT1R was able to transactivate HER2, but not HER3. Mechanistically, AT1R-mediated ERK1/2 activation was dependent on Gq/11 and EGFR tyrosine kinase activity, whereas the recruitment of Grb2 to the EGFR was independent of Gq/11 and only partially dependent on EGFR tyrosine kinase activity. This Gq/11 independence of EGFR transactivation was confirmed using AT1R mutants and in CRISPR cell lines lacking Gq/11. EGFR transactivation was also apparently independent of β-arrestins. Finally, we used additional BRET-based assays and confocal microscopy to provide evidence that both AngII- and EGF-stimulation promoted AT1R-EGFR heteromerization. In summary, we report an alternative approach to monitoring AT1R-EGFR transactivation in live cells, which provides a more direct and proximal view of this process, including the potential for complexes between the AT1R and EGFR.
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Affiliation(s)
- Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jacinta Conroy
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Melissa E Reichelt
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Brooke W Purdue
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Mohammed A Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tatsuo Kawai
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Satoru Eguchi
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Centre for Cardiac and Vasculature Biology, The University of Queensland, St Lucia 4072, Queensland, Australia.
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11
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Stoddart LA, Johnstone EKM, Wheal AJ, Goulding J, Robers MB, Machleidt T, Wood KV, Hill SJ, Pfleger KDG. Application of BRET to monitor ligand binding to GPCRs. Nat Methods 2015; 12:661-663. [PMID: 26030448 PMCID: PMC4488387 DOI: 10.1038/nmeth.3398] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/04/2015] [Indexed: 01/17/2023]
Abstract
Bioluminescence resonance energy transfer (BRET) is a well-established method for investigating protein-protein interactions. Here we present a novel BRET approach to monitor ligand binding to G protein-coupled receptors (GPCRs) on the surface of living cells made possible by the use of fluorescent ligands in combination with a novel bioluminescent protein (NanoLuc) that can be readily expressed on the N-terminus of GPCRs.
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Affiliation(s)
- Leigh A Stoddart
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
| | - Amanda J Wheal
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom
| | - Joëlle Goulding
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom
| | | | | | - Keith V Wood
- Promega Corporation, Madison, Wisconsin, United States
| | - Stephen J Hill
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom.,Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
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12
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Ayoub MA, Zhang Y, Kelly RS, See HB, Johnstone EKM, McCall EA, Williams JH, Kelly DJ, Pfleger KDG. Functional interaction between angiotensin II receptor type 1 and chemokine (C-C motif) receptor 2 with implications for chronic kidney disease. PLoS One 2015; 10:e0119803. [PMID: 25807547 PMCID: PMC4373786 DOI: 10.1371/journal.pone.0119803] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 02/02/2015] [Indexed: 11/18/2022] Open
Abstract
Understanding functional interactions between G protein-coupled receptors is of great physiological and pathophysiological importance. Heteromerization provides one important potential mechanism for such interaction between different signalling pathways via macromolecular complex formation. Previous studies suggested a functional interplay between angiotensin II receptor type 1 (AT1) and Chemokine (C-C motif) Receptor 2 (CCR2). However the molecular mechanisms are not understood. We investigated AT1-CCR2 functional interaction in vitro using bioluminescence resonance energy transfer in HEK293 cells and in vivo using subtotal-nephrectomized rats as a well-established model for chronic kidney disease. Our data revealed functional heteromers of these receptors resulting in CCR2-Gαi1 coupling being sensitive to AT1 activation, as well as apparent enhanced β-arrestin2 recruitment with agonist co-stimulation that is synergistically reversed by combined antagonist treatment. Moreover, we present in vivo findings where combined treatment with AT1- and CCR2-selective inhibitors was synergistically beneficial in terms of decreasing proteinuria, reducing podocyte loss and preventing renal injury independent of blood pressure in the subtotal-nephrectomized rat model. Our findings further support a role for G protein-coupled receptor functional heteromerization in pathophysiology and provide insights into previous observations indicating the importance of AT1-CCR2 functional interaction in inflammation, renal and hypertensive disorders.
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Affiliation(s)
- Mohammed Akli Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
| | - Yuan Zhang
- Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Robyn S. Kelly
- Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Heng B. See
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
| | | | | | - Darren J. Kelly
- Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, Australia
- Dimerix Bioscience Limited, Nedlands, Western Australia, Australia
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Abstract
Bioluminescence resonance energy transfer (BRET) is a well-established technique for investigating G protein-coupled receptor (GPCR) pharmacology. BRET enables the monitoring of molecular proximity through the use of heterologously expressed proteins of interest and/or fluorophore-labeled ligands. Fusion to a donor luciferase enzyme or an acceptor fluorophore and subsequent detection of resonance energy transfer indicate the close proximity of the molecules of interest. As BRET is readily applied to the study of numerous GPCR signaling and regulatory paths, it is an ideal technique for investigating the pharmacology of biased ligands and receptors.
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Affiliation(s)
- Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, 6 Verdun Street, Nedlands, WA, 6009, Australia
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Abstract
Receptor heteromerization has the potential to alter every facet of receptor functioning, leading to new pharmacological profiles with increased signaling diversity and regulation from that of the monomeric receptor, or indeed receptor homomer. An understanding of the molecular consequences of receptor heteromerization will provide new insights into the physiology and pathology mediated by receptors, expanding the possibilities for pharmacological discovery. Particularly advantageous approaches to investigate novel heteromer pharmacology utilize cell-based assay technologies that assess ligand-dependent functional responses specific to the receptor heteromer. Importantly, this allows for differentiation of heteromer-specific pharmacology from pharmacology associated with the co-expressed receptor monomers and homomers. The Receptor-Heteromer Investigation Technology (Receptor-HIT) successfully employs a proximity-based reporter system, such as bioluminescence resonance energy transfer (BRET), in a configuration that enables determination of such heteromer-specific pharmacology. Therefore, Receptor-HIT provides a simple, robust and versatile approach for investigating the elusive "biochemical fingerprint" of receptor heteromers.
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western AustraliaPerth, WA, Australia
| | - Kevin D. G. Pfleger
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western AustraliaPerth, WA, Australia
- Dimerix Bioscience Pty LtdPerth, WA, Australia
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