1
|
Wang T, Shao J, Kumar S, Alnouri MW, Carvalho J, Günther S, Krasel C, Murphy KT, Bünemann M, Offermanns S, Wettschureck N. Orphan GPCR GPRC5C Facilitates Angiotensin II-Induced Smooth Muscle Contraction. Circ Res 2024; 134:1259-1275. [PMID: 38597112 DOI: 10.1161/circresaha.123.323752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/29/2024] [Indexed: 04/11/2024]
Abstract
BACKGROUND GPCRs (G-protein-coupled receptors) play a central role in the regulation of smooth muscle cell (SMC) contractility, but the function of SMC-expressed orphan GPCR class C group 5 member C (GPRC5C) is unclear. The aim of this project is to define the role of GPRC5C in SMC in vitro and in vivo. METHODS We studied the role of GPRC5C in the regulation of SMC contractility and differentiation in human and murine SMC in vitro, as well as in tamoxifen-inducible, SMC-specific GPRC5C knockout mice under basal conditions and in vascular disease in vivo. RESULTS Mesenteric arteries from tamoxifen-inducible, SMC-specific GPRC5C knockout mice showed ex vivo significantly reduced angiotensin II (Ang II)-dependent calcium mobilization and contraction, whereas responses to other relaxant or contractile factors were normal. In vitro, the knockdown of GPRC5C in human aortic SMC resulted in diminished Ang II-dependent inositol phosphate production and lower myosin light chain phosphorylation. In line with this, tamoxifen-inducible, SMC-specific GPRC5C knockout mice showed reduced Ang II-induced arterial hypertension, and acute inactivation of GPRC5C was able to ameliorate established arterial hypertension. Mechanistically, we show that GPRC5C and the Ang II receptor AT1 dimerize, and knockdown of GPRC5C resulted in reduced binding of Ang II to AT1 receptors in HEK293 cells, human and murine SMC, and arteries from tamoxifen-inducible, SMC-specific GPRC5C knockout mice. CONCLUSIONS Our data show that GPRC5C regulates Ang II-dependent vascular contraction by facilitating AT1 receptor-ligand binding and signaling.
Collapse
Affiliation(s)
- Tianpeng Wang
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Jingchen Shao
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Shamit Kumar
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Mohammad Wessam Alnouri
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Jorge Carvalho
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Günther
- Bioinformatics and Deep Sequencing Platform (S.G.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Cornelius Krasel
- Department of Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Germany (C.K., M.B.)
| | - Kate T Murphy
- Department of Anatomy and Physiology, The University of Melbourne, VIC, Australia (K.T.M.)
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Germany (C.K., M.B.)
| | - Stefan Offermanns
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Medical Faculty, Goethe University Frankfurt, Germany (S.O., N.W.)
- German Center for Cardiovascular Research (DZHK), Frankfurt/Bad Nauheim, Germany (S.O., N.W.)
- Cardiopulmonary Institute, Frankfurt/Bad Nauheim, Germany (S.O., N.W.)
| | - Nina Wettschureck
- Department of Pharmacology (T.W., J.S., S.K., M.W.A., J.C., S.O., N.W.), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Medical Faculty, Goethe University Frankfurt, Germany (S.O., N.W.)
- German Center for Cardiovascular Research (DZHK), Frankfurt/Bad Nauheim, Germany (S.O., N.W.)
- Cardiopulmonary Institute, Frankfurt/Bad Nauheim, Germany (S.O., N.W.)
| |
Collapse
|
2
|
White CW, Platt S, Kilpatrick LE, Dale N, Abhayawardana RS, Dekkers S, Kindon ND, Kellam B, Stocks MJ, Pfleger KDG, Hill SJ. CXCL17 is an allosteric inhibitor of CXCR4 through a mechanism of action involving glycosaminoglycans. Sci Signal 2024; 17:eabl3758. [PMID: 38502733 PMCID: PMC7615768 DOI: 10.1126/scisignal.abl3758] [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: 07/09/2021] [Accepted: 02/29/2024] [Indexed: 03/21/2024]
Abstract
CXCL17 is a chemokine principally expressed by mucosal tissues, where it facilitates chemotaxis of monocytes, dendritic cells, and macrophages and has antimicrobial properties. CXCL17 is also implicated in the pathology of inflammatory disorders and progression of several cancers, and its expression is increased during viral infections of the lung. However, the exact role of CXCL17 in health and disease requires further investigation, and there is a need for confirmed molecular targets mediating CXCL17 functional responses. Using a range of bioluminescence resonance energy transfer (BRET)-based assays, here we demonstrated that CXCL17 inhibited CXCR4-mediated signaling and ligand binding. Moreover, CXCL17 interacted with neuropillin-1, a VEGFR2 coreceptor. In addition, we found that CXCL17 only inhibited CXCR4 ligand binding in intact cells and demonstrated that this effect was mimicked by known glycosaminoglycan binders, surfen and protamine sulfate. Disruption of putative GAG binding domains in CXCL17 prevented CXCR4 binding. This indicated that CXCL17 inhibited CXCR4 by a mechanism of action that potentially required the presence of a glycosaminoglycan-containing accessory protein. Together, our results revealed that CXCL17 is an endogenous inhibitor of CXCR4 and represents the next step in our understanding of the function of CXCL17 and regulation of CXCR4 signaling.
Collapse
Affiliation(s)
- Carl W. White
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
- Dimerix Limited, Melbourne, Australia
| | - Simon Platt
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Laura E. Kilpatrick
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Natasha Dale
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Rekhati S. Abhayawardana
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Sebastian Dekkers
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Nicholas D Kindon
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Barrie Kellam
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Michael J Stocks
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Kevin D. G. Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
- Dimerix Limited, Melbourne, Australia
| | - Stephen J. Hill
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| |
Collapse
|
3
|
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: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [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.
Collapse
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,
| |
Collapse
|
4
|
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] [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.
Collapse
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,
| |
Collapse
|
5
|
Profiling novel pharmacology of receptor complexes using Receptor-HIT. Biochem Soc Trans 2021; 49:1555-1565. [PMID: 34436548 PMCID: PMC8421044 DOI: 10.1042/bst20201110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 02/07/2023]
Abstract
Many receptors are able to undergo heteromerisation, leading to the formation of receptor complexes that may have pharmacological profiles distinct from those of the individual receptors. As a consequence of this, receptor heteromers can be classed as new drug targets, with the potential for achieving greater specificity and selectivity over targeting their constituent receptors. We have developed the Receptor-Heteromer Investigation Technology (Receptor-HIT), which enables the detection of receptor heteromers using a proximity-based reporter system such as bioluminescence resonance energy transfer (BRET). Receptor-HIT detects heteromers in live cells and in real time, by utilising ligand-induced signals that arise from altered interactions with specific biomolecules, such as ligands or proteins. Furthermore, monitoring the interaction between the receptors and the specific biomolecules generates functional information about the heteromer that can be pharmacologically quantified. This review will discuss various applications of Receptor-HIT, including its use with different classes of receptors (e.g. G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and others), its use to monitor receptor interactions both intracellularly and extracellularly, and also its use with genome-edited endogenous proteins.
Collapse
|
6
|
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] [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.
Collapse
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.
| |
Collapse
|
7
|
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] [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).
Collapse
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
| |
Collapse
|
8
|
Quitterer U, AbdAlla S. Discovery of Pathologic GPCR Aggregation. Front Med (Lausanne) 2019; 6:9. [PMID: 30761305 PMCID: PMC6363654 DOI: 10.3389/fmed.2019.00009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/14/2019] [Indexed: 01/02/2023] Open
Abstract
The family of G-protein-coupled receptors (GPCRs) is one of the most important drug targets. Mechanisms underlying GPCR activation and signaling are therefore of great pharmacologic interest. It was long thought that GPCRs exist and function as monomers. This feature was considered to distinguish GPCRs from other membrane receptors such as receptor tyrosine kinases or cytokine receptors, which signal from dimeric receptor complexes. But during the last two decades it was increasingly recognized that GPCRs can undergo aggregation to form dimers and higher order oligomers, resulting in homomeric and/or heteromeric protein complexes with different stoichiometries. Moreover, this protein complex formation could modify GPCR signaling and function. We contributed to this paradigm shift in GPCR pharmacology by the discovery of the first pathologic GPCR aggregation, which is the protein complex formation between the angiotensin II AT1 receptor and the bradykinin B2 receptor. Increased AT1-B2 heteromerization accounts for the angiotensin II hypersensitivity of pregnant women with preeclampsia hypertension. Since the discovery of AT1-B2, other pathologic GPCR aggregates were found, which contribute to atherosclerosis, neurodegeneration and Alzheimer's disease. As a result of our findings, pathologic GPCR aggregation appears as an independent and disease-specific process, which is increasingly considered as a novel target for pharmacologic intervention.
Collapse
Affiliation(s)
- Ursula Quitterer
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland.,Department of Medicine, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Said AbdAlla
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| |
Collapse
|
9
|
Susec M, Sencanski M, Glisic S, Veljkovic N, Pedersen C, Drinovec L, Stojan J, Nøhr J, Vrecl M. Functional characterization of β 2-adrenergic and insulin receptor heteromers. Neuropharmacology 2019; 152:78-89. [PMID: 30707913 DOI: 10.1016/j.neuropharm.2019.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/01/2019] [Accepted: 01/23/2019] [Indexed: 01/06/2023]
Abstract
This study aimed to functionally characterize β2-adrenergic (β2AR) and insulin receptor (IR) heteromers in regard to β-arrestin 2 (βarr2) recruitment and cAMP signaling and to examine the involvement of the cytoplasmic portion of the IR β chain in heteromerization with β2AR. Evidence for β2AR:IR:βarr2 complex formation and the specificity of the IR:βarr2 interaction was first provided by bioinfomatics analysis. Receptor-heteromer investigation technology (HIT) then provided functional evidence of β2AR:IR heterodimerization by showing isoproterenol-induced but not insulin-induced GFP2-βarr2 recruitment to the β2AR:IR complex; the IR:βarr2 interaction was found to only be constitutive. The constitutive IR:βarr2 BRET signal (BRETconst) was significantly smaller in cells coexpressing IR-RLuc8 and a GFP2-βarr2 1-185 mutant lacking the proposed IR binding domain. β2AR:IR heteromerization also influenced the pharmacological phenotype of β2AR, i.e., its efficacy in recruiting βarr2 and activating cAMP signaling. Evidence suggesting involvement of the cytoplasmic portion of the IR β chain in the interaction with β2AR was provided by BRET2 saturation and HIT assays using an IR 1-1271 stop mutant lacking the IR C-terminal tail region. For the complex consisting of IR 1-1271-RLuc8:β2AR-GFP2, saturation was not reached, most likely reflecting random collisions between IR 1-1271 and β2AR. Furthermore, in the HIT assay, no substantial agonist-induced increase in the BRET2 signal was detected that would be indicative of βarr2 recruitment to the IR 1-1271:β2AR heteromer. Complementary 3D visualization of β2AR:IR provided supporting evidence for stability of the heterotetramer complex and identified amino acid residues involved in β2AR:IR heteromerization. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.
Collapse
Affiliation(s)
- Maja Susec
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia
| | - Milan Sencanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Sanja Glisic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Nevena Veljkovic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Christina Pedersen
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Luka Drinovec
- Department of Condensed Matter Physics, Jožef Stefan Institute, Slovenia
| | - Jurij Stojan
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jane Nøhr
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia.
| |
Collapse
|
10
|
Felce JH, MacRae A, Davis SJ. Constraints on GPCR Heterodimerization Revealed by the Type-4 Induced-Association BRET Assay. Biophys J 2019; 116:31-41. [PMID: 30558888 PMCID: PMC6341220 DOI: 10.1016/j.bpj.2018.09.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/14/2018] [Accepted: 09/21/2018] [Indexed: 01/24/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) comprise the largest and most pharmacologically important family of cell-surface receptors encoded by the human genome. In many instances, the distinct signaling behavior of certain GPCRs has been explained in terms of the formation of heteromers with, for example, distinct signaling properties and allosteric cross-regulation. Confirmation of this has, however, been limited by the paucity of reliable methods for probing heteromeric GPCR interactions in situ. The most widely used assays for GPCR stoichiometry, based on resonance energy transfer, are unsuited to reporting heteromeric interactions. Here, we describe a targeted bioluminescence resonance energy transfer (BRET) assay, called type-4 BRET, which detects both homo- and heteromeric interactions using induced multimerization of protomers within such complexes, at constant expression. Using type-4 BRET assays, we investigate heterodimerization among known GPCR homodimers: the CXC chemokine receptor 4 and sphingosine-1-phosphate receptors. We observe that CXC chemokine receptor 4 and sphingosine-1-phosphate receptors can form heterodimers with GPCRs from their immediate subfamilies but not with more distantly related receptors. We also show that heterodimerization appears to disrupt homodimeric interactions, suggesting the sharing of interfaces. Broadly, these observations indicate that heterodimerization results from the divergence of homodimeric receptors and will therefore likely be restricted to closely related homodimeric GPCRs.
Collapse
Affiliation(s)
- James H Felce
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, United Kingdom; Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, United Kingdom.
| | - Alasdair MacRae
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, United Kingdom; Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - Simon J Davis
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, United Kingdom; Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, United Kingdom
| |
Collapse
|
11
|
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: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [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.
Collapse
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.
| |
Collapse
|
12
|
Gahbauer S, Pluhackova K, Böckmann RA. Closely related, yet unique: Distinct homo- and heterodimerization patterns of G protein coupled chemokine receptors and their fine-tuning by cholesterol. PLoS Comput Biol 2018; 14:e1006062. [PMID: 29529028 PMCID: PMC5864085 DOI: 10.1371/journal.pcbi.1006062] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/22/2018] [Accepted: 02/28/2018] [Indexed: 12/21/2022] Open
Abstract
Chemokine receptors, a subclass of G protein coupled receptors (GPCRs), play essential roles in the human immune system, they are involved in cancer metastasis as well as in HIV-infection. A plethora of studies show that homo- and heterodimers or even higher order oligomers of the chemokine receptors CXCR4, CCR5, and CCR2 modulate receptor function. In addition, membrane cholesterol affects chemokine receptor activity. However, structural information about homo- and heterodimers formed by chemokine receptors and their interplay with cholesterol is limited. Here, we report homo- and heterodimer configurations of the chemokine receptors CXCR4, CCR5, and CCR2 at atomistic detail, as obtained from thousands of molecular dynamics simulations. The observed homodimerization patterns were similar for the closely related CC chemokine receptors, yet they differed significantly between the CC receptors and CXCR4. Despite their high sequence identity, cholesterol modulated the CC homodimer interfaces in a subtype-specific manner. Chemokine receptor heterodimers display distinct dimerization patterns for CXCR4/CCR5 and CXCR4/CCR2. Furthermore, associations between CXCR4 and CCR5 reveal an increased cholesterol-sensitivity as compared to CXCR4/CCR2 heterodimerization patterns. This work provides a first comprehensive structural overview over the complex interaction network between chemokine receptors and indicates how heterodimerization and the interaction with the membrane environment diversifies the function of closely related GPCRs.
Collapse
MESH Headings
- Animals
- Chemokines/metabolism
- Cholesterol/metabolism
- Computer Simulation
- Dimerization
- Humans
- Molecular Dynamics Simulation
- Receptors, CCR2/chemistry
- Receptors, CCR2/metabolism
- Receptors, CCR2/ultrastructure
- Receptors, CCR5/chemistry
- Receptors, CCR5/metabolism
- Receptors, CCR5/ultrastructure
- Receptors, CXCR4/chemistry
- Receptors, CXCR4/metabolism
- Receptors, CXCR4/ultrastructure
- Receptors, Chemokine/chemistry
- Receptors, Chemokine/genetics
- Receptors, G-Protein-Coupled/genetics
- Signal Transduction
Collapse
Affiliation(s)
- Stefan Gahbauer
- Computational Biology, Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Kristyna Pluhackova
- Computational Biology, Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Rainer A. Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| |
Collapse
|
13
|
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
|
14
|
Using nanoBRET and CRISPR/Cas9 to monitor proximity to a genome-edited protein in real-time. Sci Rep 2017; 7:3187. [PMID: 28600500 PMCID: PMC5466623 DOI: 10.1038/s41598-017-03486-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/28/2017] [Indexed: 12/15/2022] Open
Abstract
Bioluminescence resonance energy transfer (BRET) has been a vital tool for understanding G protein-coupled receptor (GPCR) function. It has been used to investigate GPCR-protein and/or -ligand interactions as well as GPCR oligomerisation. However the utility of BRET is limited by the requirement that the fusion proteins, and in particular the donor, need to be exogenously expressed. To address this, we have used CRISPR/Cas9-mediated homology-directed repair to generate protein-Nanoluciferase (Nluc) fusions under endogenous promotion, thus allowing investigation of proximity between the genome-edited protein and an exogenously expressed protein by BRET. Here we report BRET monitoring of GPCR-mediated β-arrestin2 recruitment and internalisation where the donor luciferase was under endogenous promotion, in live cells and in real time. We have investigated the utility of CRISPR/Cas9 genome editing to create genome-edited fusion proteins that can be used as BRET donors and propose that this strategy can be used to overcome the need for exogenous donor expression.
Collapse
|
15
|
Tóth AD, Gyombolai P, Szalai B, Várnai P, Turu G, Hunyady L. Angiotensin type 1A receptor regulates β-arrestin binding of the β 2-adrenergic receptor via heterodimerization. Mol Cell Endocrinol 2017; 442:113-124. [PMID: 27908837 DOI: 10.1016/j.mce.2016.11.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/26/2016] [Accepted: 11/26/2016] [Indexed: 02/06/2023]
Abstract
Heterodimerization between angiotensin type 1A receptor (AT1R) and β2-adrenergic receptor (β2AR) has been shown to modulate G protein-mediated effects of these receptors. Activation of G protein-coupled receptors (GPCRs) leads to β-arrestin binding, desensitization, internalization and G protein-independent signaling of GPCRs. Our aim was to study the effect of heterodimerization on β-arrestin coupling. We found that β-arrestin binding of β2AR is affected by activation of AT1Rs. Costimulation with angiotensin II and isoproterenol markedly enhanced the interaction between β2AR and β-arrestins, by prolonging the lifespan of β2AR-induced β-arrestin2 clusters at the plasma membrane. While candesartan, a conventional AT1R antagonist, had no effect on the β-arrestin2 binding to β2AR, TRV120023, a β-arrestin biased agonist, enhanced the interaction. These findings reveal a new crosstalk mechanism between AT1R and β2AR, and suggest that enhanced β-arrestin2 binding to β2AR can contribute to the pharmacological effects of biased AT1R agonists.
Collapse
Affiliation(s)
- András D Tóth
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary
| | - Pál Gyombolai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Bence Szalai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary
| | - Gábor Turu
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.
| |
Collapse
|
16
|
O'Brien DE, Conn PJ. Neurobiological Insights from mGlu Receptor Allosteric Modulation. Int J Neuropsychopharmacol 2016; 19:pyv133. [PMID: 26647381 PMCID: PMC4886670 DOI: 10.1093/ijnp/pyv133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/15/2015] [Accepted: 12/02/2015] [Indexed: 12/25/2022] Open
Abstract
Allosteric modulation of metabotropic glutamate (mGlu) receptors offers a promising pharmacological approach to normalize neural circuit dysfunction associated with various psychiatric and neurological disorders. As mGlu receptor allosteric modulators progress through discovery and clinical development, both technical advances and novel tool compounds are providing opportunities to better understand mGlu receptor pharmacology and neurobiology. Recent advances in structural biology are elucidating the structural determinants of mGlu receptor-negative allosteric modulation and supplying the means to resolve active, allosteric modulator-bound mGlu receptors. The discovery and characterization of allosteric modulators with novel pharmacological profiles is uncovering the biological significance of their intrinsic agonist activity, biased mGlu receptor modulation, and novel mGlu receptor heterodimers. The development and exploitation of optogenetic and optopharmacological tools is permitting a refined spatial and temporal understanding of both mGlu receptor functions and their allosteric modulation in intact brain circuits. Together, these lines of research promise to provide a more refined understanding of mGlu receptors and their allosteric modulation that will inform the development of mGlu receptor allosteric modulators as neurotherapeutics in the years to come.
Collapse
Affiliation(s)
- Daniel E O'Brien
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee (Drs O'Brien and Conn)
| | - P Jeffrey Conn
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee (Drs O'Brien and Conn).
| |
Collapse
|
17
|
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
|
18
|
Griffiths K, Dolezal O, Cao B, Nilsson SK, See HB, Pfleger KDG, Roche M, Gorry PR, Pow A, Viduka K, Lim K, Lu BGC, Chang DHC, Murray-Rust T, Kvansakul M, Perugini MA, Dogovski C, Doerflinger M, Zhang Y, Parisi K, Casey JL, Nuttall SD, Foley M. i-bodies, Human Single Domain Antibodies That Antagonize Chemokine Receptor CXCR4. J Biol Chem 2016; 291:12641-12657. [PMID: 27036939 DOI: 10.1074/jbc.m116.721050] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Indexed: 01/20/2023] Open
Abstract
CXCR4 is a G protein-coupled receptor with excellent potential as a therapeutic target for a range of clinical conditions, including stem cell mobilization, cancer prognosis and treatment, fibrosis therapy, and HIV infection. We report here the development of a fully human single-domain antibody-like scaffold termed an "i-body," the engineering of which produces an i-body library possessing a long complementarity determining region binding loop, and the isolation and characterization of a panel of i-bodies with activity against human CXCR4. The CXCR4-specific i-bodies show antagonistic activity in a range of in vitro and in vivo assays, including inhibition of HIV infection, cell migration, and leukocyte recruitment but, importantly, not the mobilization of hematopoietic stem cells. Epitope mapping of the three CXCR4 i-bodies AM3-114, AM4-272, and AM3-523 revealed binding deep in the binding pocket of the receptor.
Collapse
Affiliation(s)
| | - Olan Dolezal
- Biomedical Manufacturing, CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052
| | - Benjamin Cao
- the Australian Regenerative Medicine Institute, Monash University, Wellington Road, Clayton, Victoria 3800,; Biomedical Manufacturing, CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168
| | - Susan K Nilsson
- the Australian Regenerative Medicine Institute, Monash University, Wellington Road, Clayton, Victoria 3800,; Biomedical Manufacturing, CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168
| | - Heng B See
- the Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009,; the Centre for Medical Research, University of Western Australia, Crawley, Western Australia 6009
| | - Kevin D G Pfleger
- the Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009,; the Centre for Medical Research, University of Western Australia, Crawley, Western Australia 6009,; Dimerix Bioscience Ltd., Nedlands, Western Australia 6009
| | - Michael Roche
- the Doherty Institute for Infection and Immunity, University of Melbourne, 792 Elizabeth Street, Melbourne, Victoria 3000,; the Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004
| | - Paul R Gorry
- the School of Health and Biomedical Sciences, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3001
| | - Andrew Pow
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083
| | - Katerina Viduka
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083
| | - Kevin Lim
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083
| | | | | | | | - Marc Kvansakul
- the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, and
| | - Matthew A Perugini
- the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, and
| | - Con Dogovski
- the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, and
| | | | - Yuan Zhang
- the Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, Victoria 3065, Australia
| | - Kathy Parisi
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083,; the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, and
| | - Joanne L Casey
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083
| | - Stewart D Nuttall
- Biomedical Manufacturing, CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052
| | - Michael Foley
- From AdAlta Pty. Ltd., 15/2 Park Dr., Bundoora, Victoria 3083,; the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, and.
| |
Collapse
|
19
|
Abstract
Since their discovery, G protein-coupled receptors (GPCRs) constitute one of the most studied proteins leading to important discoveries and perspectives in terms of their biology and implication in physiology and pathophysiology. This is mostly linked to the remarkable advances in the development and application of the biophysical resonance energy transfer (RET)-based approaches, including bioluminescence and fluorescence resonance energy transfer (BRET and FRET, respectively). Indeed, BRET and FRET have been extensively applied to study different aspects of GPCR functioning such as their activation and regulation either statically or dynamically, in real-time and intact cells. Consequently, our view on GPCRs has considerably changed opening new challenges for the study of GPCRs in their native tissues in the aim to get more knowledge on how these receptors control the biological responses. Moreover, the technological aspect of this field of research promises further developments for robust and reliable new RET-based assays that may be compatible with high-throughput screening as well as drug discovery programs.
Collapse
Affiliation(s)
- Mohammed Akli Ayoub
- Biologie et Bioinformatique des Systèmes de Signalisation, Institut National de la Recherche Agronomique, UMR85, Unité Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Nouzilly, France; LE STUDIUM(®) Loire Valley Institute for Advanced Studies, Orléans, France.
| |
Collapse
|
20
|
Abstract
G protein-coupled receptors (GPCRs) compose one of the largest families of membrane proteins involved in intracellular signaling. They are involved in numerous physiological and pathological processes and are prime candidates for drug development. Over the past decade, an increasing number of studies have reported heteromerization between GPCRs. Many investigations in heterologous systems have provided important indications of potential novel pharmacology; however, the physiological relevance of these findings has yet to be established with endogenous receptors in native tissues. In this review, we focus on family A GPCRs and describe the techniques and criteria to assess their heteromerization. We conclude that advances in approaches to study receptor complex functionality in heterologous systems, coupled with techniques that enable specific examination of native receptor heteromers in vivo, are likely to establish GPCR heteromers as novel therapeutic targets.
Collapse
Affiliation(s)
- Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029;
| | - Mohammed Akli Ayoub
- Biologie et Bioinformatique des Systèmes de Signalisation (BIOS) Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, F-37380 Nouzilly, France
- LE STUDIUM Loire Valley Institute for Advanced Studies, F-45000 Orleans, France
| | - Wakako Fujita
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029;
- Current address: Department of Frontier Life Sciences, Nagasaki University, Nagasaki City, Nagasaki Prefecture 852-8588, Japan
| | - Werner C Jaeger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
- Dimerix Bioscience Limited, Nedlands, Western Australia 6009, Australia
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029;
| |
Collapse
|
21
|
Vischer HF, Castro M, Pin JP. G Protein-Coupled Receptor Multimers: A Question Still Open Despite the Use of Novel Approaches. Mol Pharmacol 2015; 88:561-71. [PMID: 26138074 DOI: 10.1124/mol.115.099440] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/02/2015] [Indexed: 12/11/2022] Open
Abstract
Heteromerization of G protein-coupled receptors (GPCRs) can significantly change the functional properties of involved receptors. Various biochemical and biophysical methodologies have been developed in the last two decades to identify and functionally evaluate GPCR heteromers in heterologous cells, with recent approaches focusing on GPCR complex stoichiometry and stability. Yet validation of these observations in native tissues is still lagging behind for the majority of GPCR heteromers. Remarkably, recent studies, particularly some involving advanced fluorescence microscopy techniques, are contributing to our current knowledge of aspects that were not well known until now, such as GPCR complex stoichiometry and stability. In parallel, a growing effort is being applied to move the field forward into native systems. This short review will highlight recent developments to study the stoichiometry and stability of GPCR complexes and methodologies to detect native GPCR dimers.
Collapse
Affiliation(s)
- Henry F Vischer
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (H.F.V.); Molecular Pharmacology Laboratory, Biofarma Research Group (GI-1685), University of Santiago de Compostela, Center for Research in Molecular Medicine and Chronic Diseases, Santiago de Compostela, Spain (M.C.); and Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France (J.-P.P.)
| | - Marián Castro
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (H.F.V.); Molecular Pharmacology Laboratory, Biofarma Research Group (GI-1685), University of Santiago de Compostela, Center for Research in Molecular Medicine and Chronic Diseases, Santiago de Compostela, Spain (M.C.); and Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France (J.-P.P.)
| | - Jean-Philippe Pin
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands (H.F.V.); Molecular Pharmacology Laboratory, Biofarma Research Group (GI-1685), University of Santiago de Compostela, Center for Research in Molecular Medicine and Chronic Diseases, Santiago de Compostela, Spain (M.C.); and Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France (J.-P.P.)
| |
Collapse
|
22
|
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] [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.
Collapse
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
| |
Collapse
|
23
|
Johnstone EKM, Pfleger KDG. Bioluminescence Resonance Energy Transfer Approaches to Discover Bias in GPCR Signaling. Methods Mol Biol 2015; 1335:191-204. [PMID: 26260602 DOI: 10.1007/978-1-4939-2914-6_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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.
Collapse
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
| | | |
Collapse
|
24
|
Chen X, Bai B, Tian Y, Du H, Chen J. Identification of serine 348 on the apelin receptor as a novel regulatory phosphorylation site in apelin-13-induced G protein-independent biased signaling. J Biol Chem 2014; 289:31173-87. [PMID: 25271156 DOI: 10.1074/jbc.m114.574020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Phosphorylation plays vital roles in the regulation of G protein-coupled receptor (GPCR) functions. The apelin and apelin receptor (APJ) system is involved in the regulation of cardiovascular function and central control of body homeostasis. Here, using tandem mass spectrometry, we first identified phosphorylated serine residues in the C terminus of APJ. To determine the role of phosphorylation sites in APJ-mediated G protein-dependent and -independent signaling and function, we induced a mutation in the C-terminal serine residues and examined their effects on the interaction between APJ with G protein or GRK/β-arrestin and their downstream signaling. Mutation of serine 348 led to an elimination of both GRK and β-arrestin recruitment to APJ induced by apelin-13. Moreover, APJ internalization and G protein-independent ERK signaling were also abolished by point mutation at serine 348. In contrast, this mutant at serine residues had no demonstrable impact on apelin-13-induced G protein activation and its intracellular signaling. These findings suggest that mutation of serine 348 resulted in inactive GRK/β-arrestin. However, there was no change in the active G protein thus, APJ conformation was biased. These results provide important information on the molecular interplay and impact of the APJ function, which may be extrapolated to design novel drugs for cardiac hypertrophy based on this biased signal pathway.
Collapse
Affiliation(s)
- Xiaoyu Chen
- From the Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, People's Republic of China, the Department of physiology, Taishan Medical College, Taian, Shandong 271000, People's Republic of China
| | - Bo Bai
- the Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, People's Republic of China,
| | - Yanjun Tian
- the Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, People's Republic of China
| | - Hui Du
- the Department of physiology, Taishan Medical College, Taian, Shandong 271000, People's Republic of China
| | - Jing Chen
- the Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, People's Republic of China, the Division of Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom, and
| |
Collapse
|
25
|
Stephens B, Handel TM. Chemokine receptor oligomerization and allostery. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 115:375-420. [PMID: 23415099 DOI: 10.1016/b978-0-12-394587-7.00009-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oligomerization of chemokine receptors has been reported to influence many aspects of receptor function through allosteric communication between receptor protomers. Allosteric interactions within chemokine receptor hetero-oligomers have been shown to cause negative cooperativity in the binding of chemokines and to inhibit receptor activation in the case of some receptor pairs. Other receptor pairs can cause enhanced signaling and even activate entirely new, hetero-oligomer-specific signaling complexes and responses downstream of receptor activation. Many mechanisms contribute to these effects including direct allosteric coupling between the receptors, G protein-mediated allostery, G protein stealing, ligand sequestration, and recruitment of new intracellular proteins by exposing unique binding interfaces on the oligomerized receptors. These effects present both challenges as well as exciting opportunities for drug discovery. One of the most difficult challenges will involve determining if and when hetero-oligomers versus homomeric receptors are involved in specific disease states.
Collapse
Affiliation(s)
- Bryan Stephens
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, California, USA
| | | |
Collapse
|
26
|
Arnolds KL, Spencer JV. CXCR4: a virus's best friend? INFECTION GENETICS AND EVOLUTION 2014; 25:146-56. [PMID: 24793563 DOI: 10.1016/j.meegid.2014.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 10/25/2022]
Abstract
Viruses are dependent on their hosts for replication and dispersal in the environment; thus, the most successful viruses are those that co-evolve with their hosts. CXCR4 is a cellular chemokine receptor that plays central roles in development, hematopoiesis, and immune surveillance through signaling induced by its ligand, CXCL12. The CXCR4-CXCL12 axis has been besieged by many pathogens that employ a range of strategies to modify or exploit CXCR4 activity. While CXCR4 was identified as a critical co-factor for entry of HIV into CD4+ T cells early on, other viruses may utilize CXCR4 to gain cell entry as well. Moreover, several viruses have been found to modulate CXCR4 expression or alter its functional activity, with direct effects on cell trafficking, immune responses, cell proliferation, and cell survival. Because CXCR4 is targeted by a diverse group of viral pathogens, modification of host CXCR4 signaling activity is emerging as a common theme in virus persistence and is likely to be important for subversion of the host immune system. This review highlights major viral pathogens that use and abuse CXCR4 and explores the possible reasons why this chemokine receptor has become "a virus's best friend".
Collapse
Affiliation(s)
- Kathleen L Arnolds
- Department of Biology, University of San Francisco, 2130 Fulton Street, San Francisco, CA 94403, United States
| | - Juliet V Spencer
- Department of Biology, University of San Francisco, 2130 Fulton Street, San Francisco, CA 94403, United States.
| |
Collapse
|
27
|
Vasopressor meets vasodepressor: The AT1-B2 receptor heterodimer. Biochem Pharmacol 2014; 88:284-90. [PMID: 24462918 DOI: 10.1016/j.bcp.2014.01.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 01/08/2023]
Abstract
The AT1 receptor for the vasopressor angiotensin II is one of the most important drug targets for the treatment of cardiovascular diseases. Sensitization of the AT1 receptor system is a common feature contributing to the pathogenesis of many cardiovascular disorders but underlying mechanisms are not fully understood. More than a decade ago, evidence was provided for control of AT1R activation by heterodimerization with the B2 receptor for the vasodepressor peptide, bradykinin, a physiological counterpart of the vasoconstrictor angiotensin II. AT1-B2 receptor heterodimerization was shown to enhance AT1R-stimulated signaling under pathophysiological conditions such as experimental and human pregnancy hypertension. Notably, AT1R signal sensitization of patients with preeclampsia hypertension was attributed to AT1R-B2R heterodimerization. Vice versa, transgenic mice lacking the AT1-B2 receptor heterodimer due to targeted deletion of the B2R gene showed a significantly reduced AT1R-stimulated vasopressor response compared to transgenic mice with abundant AT1R-B2R heterodimerization. Biophysical methods such as BRET and FRET confirmed those data by demonstrating efficient AT1-B2 receptor heterodimerization in transfected cells and transgenic mice. Recently, a study on AT1R-specific biased agonism directed the focus to the AT1-B2 receptor heterodimer again. The β-arrestin-biased [Sar1,Ile4,Ile8]-angiotensin II promoted not only the recruitment of β-arrestin to the AT1R but also stimulated the down-regulation of the AT1R-associated B2 receptor by co-internalization. Thereby specific targeting of the AT1R-B2R heterodimer became feasible and could open the way to a new class of drugs, which specifically interfere with pathological angiotensin II-AT1 receptor system activation.
Collapse
|
28
|
Jaeger WC, Armstrong SP, Hill SJ, Pfleger KDG. Biophysical Detection of Diversity and Bias in GPCR Function. Front Endocrinol (Lausanne) 2014; 5:26. [PMID: 24634666 PMCID: PMC3943086 DOI: 10.3389/fendo.2014.00026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 02/19/2014] [Indexed: 12/27/2022] Open
Abstract
Guanine nucleotide binding protein (G protein)-coupled receptors (GPCRs) function in complexes with a range of molecules and proteins including ligands, G proteins, arrestins, ubiquitin, and other receptors. Elements of these complexes may interact constitutively or dynamically, dependent upon factors such as ligand binding, phosphorylation, and dephosphorylation. They may also be allosterically modulated by other proteins in a manner that changes temporally and spatially within the cell. Elucidating how these complexes function has been greatly enhanced by biophysical technologies that are able to monitor proximity and/or binding, often in real time and in live cells. These include resonance energy transfer approaches such as bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET). Furthermore, the use of fluorescent ligands has enabled novel insights into allosteric interactions between GPCRs. Consequently, biophysical approaches are helping to unlock the amazing diversity and bias in G protein-coupled receptor signaling.
Collapse
Affiliation(s)
- Werner C. Jaeger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Stephen P. Armstrong
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Stephen J. Hill
- Cell Signalling Research Group, School of Life Sciences, Queen’s Medical Centre, University of Nottingham Medical School, Nottingham, UK
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Dimerix Bioscience Pty Ltd, Perth, WA, Australia
- *Correspondence: Kevin D. G. Pfleger, Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, QQ Block, 6 Verdun Street, Nedlands, Perth, WA 6009, Australia e-mail:
| |
Collapse
|
29
|
Watts AO, van Lipzig MMH, Jaeger WC, Seeber RM, van Zwam M, Vinet J, van der Lee MMC, Siderius M, Zaman GJR, Boddeke HWGM, Smit MJ, Pfleger KDG, Leurs R, Vischer HF. Identification and profiling of CXCR3-CXCR4 chemokine receptor heteromer complexes. Br J Pharmacol 2013; 168:1662-74. [PMID: 23170857 DOI: 10.1111/bph.12064] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/29/2012] [Accepted: 10/29/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The C-X-C chemokine receptors 3 (CXCR3) and C-X-C chemokine receptors 4 (CXCR4) are involved in various autoimmune diseases and cancers. Small antagonists have previously been shown to cross-inhibit chemokine binding to CXCR4, CC chemokine receptors 2 (CCR2) and 5 (CCR5) heteromers. We investigated whether CXCR3 and CXCR4 can form heteromeric complexes and the binding characteristics of chemokines and small ligand compounds to these chemokine receptor heteromers. EXPERIMENTAL APPROACH CXCR3-CXCR4 heteromers were identified in HEK293T cells using co-immunoprecipitation, time-resolved fluorescence resonance energy transfer, saturation BRET and the GPCR-heteromer identification technology (HIT) approach. Equilibrium competition binding and dissociation experiments were performed to detect negative binding cooperativity. KEY RESULTS We provide evidence that chemokine receptors CXCR3 and CXCR4 form heteromeric complexes in HEK293T cells. Chemokine binding was mutually exclusive on membranes co-expressing CXCR3 and CXCR4 as revealed by equilibrium competition binding and dissociation experiments. The small CXCR3 agonist VUF10661 impaired binding of CXCL12 to CXCR4, whereas small antagonists were unable to cross-inhibit chemokine binding to the other chemokine receptor. In contrast, negative binding cooperativity between CXCR3 and CXCR4 chemokines was not observed in intact cells. However, using the GPCR-HIT approach, we have evidence for specific β-arrestin2 recruitment to CXCR3-CXCR4 heteromers in response to agonist stimulation. CONCLUSIONS AND IMPLICATIONS This study indicates that heteromeric CXCR3-CXCR4 complexes may act as functional units in living cells, which potentially open up novel therapeutic opportunities.
Collapse
Affiliation(s)
- A O Watts
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Science, VU University Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Ayoub MA, See HB, Seeber RM, Armstrong SP, Pfleger KDG. Profiling epidermal growth factor receptor and heregulin receptor 3 heteromerization using receptor tyrosine kinase heteromer investigation technology. PLoS One 2013; 8:e64672. [PMID: 23700486 PMCID: PMC3659105 DOI: 10.1371/journal.pone.0064672] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 04/17/2013] [Indexed: 11/18/2022] Open
Abstract
Heteromerization can play an important role in regulating the activation and/or signal transduction of most forms of receptors, including receptor tyrosine kinases (RTKs). The study of receptor heteromerization has evolved extensively with the emergence of resonance energy transfer based approaches such as bioluminescence resonance energy transfer (BRET). Here, we report an adaptation of our Receptor-Heteromer Investigation Technology (Receptor-HIT) that has recently been published as the G protein-coupled receptor (GPCR) Heteromer Identification Technology (GPCR-HIT). We now demonstrate the utility of this approach for investigating RTK heteromerization by examining the functional interaction between the epidermal growth factor (EGF) receptor (EGFR; also known as erbB1/HER1) and heregulin (HRG) receptor 3 (HER3; also known as erbB3) in live HEK293FT cells using recruitment of growth factor receptor-bound protein 2 (Grb2) to the activated receptors. We found that EGFR and HER3 heteromerize specifically as demonstrated by HRG inducing a BRET signal between EGFR/Rluc8 and Grb2/Venus only when HER3 was co-expressed. Similarly, EGF stimulation promoted a specific BRET signal between HER3/Rluc8 and Grb2/Venus only when EGFR was co-expressed. Both EGF and HRG effects on Grb2 interaction are dose-dependent, and specifically blocked by EGFR inhibitor AG-1478. Furthermore, truncation of HER3 to remove the putative Grb2 binding sites appears to abolish EGF-induced Grb2 recruitment to the EGFR-HER3 heteromer. Our results support the concept that EGFR interacts with Grb2 in both constitutive and EGF-dependent manners and this interaction is independent of HER3 co-expression. In contrast, HER3-Grb2 interaction requires the heteromerization between EGFR and HER3. These findings clearly indicate the importance of EGFR-HER3 heteromerization in HER3-mediated Grb2-dependent signaling pathways and supports the central role of HER3 in the diversity and regulation of HER family functioning.
Collapse
Affiliation(s)
- Mohammed Akli Ayoub
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
- Protein Research Chair - Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Heng B. See
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Ruth M. Seeber
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Stephen P. Armstrong
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Kevin D. G. Pfleger
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
- Dimerix Bioscience Pty Ltd, Nedlands, Western Australia, Australia
- * E-mail:
| |
Collapse
|
31
|
Hansen JT, Lyngsø C, Speerschneider T, Hansen PBL, Galés C, Weiner DM, Sheikh SP, Burstein ES, Hansen JL. Functional enhancement of AT1R potency in the presence of the TPαR is revealed by a comprehensive 7TM receptor co-expression screen. PLoS One 2013; 8:e58890. [PMID: 23516570 PMCID: PMC3597553 DOI: 10.1371/journal.pone.0058890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 02/07/2013] [Indexed: 01/14/2023] Open
Abstract
Background Functional cross-talk between seven transmembrane (7TM) receptors can dramatically alter their pharmacological properties, both in vitro and in vivo. This represents an opportunity for the development of novel therapeutics that potentially target more specific biological effects while causing fewer adverse events. Although several studies convincingly have established the existence of 7TM receptor cross-talk, little is known about the frequencey and biological significance of this phenomenon. Methodology/Principal Findings To evaluate the extent of synergism in 7TM receptor signaling, we took a comprehensive approach and co-expressed 123 different 7TM receptors together with the angiotensin II type 1 receptor (AT1R) and analyzed how each receptor affected the angiotensin II (AngII) response. To monitor the effect we used integrative receptor activation/signaling assay called Receptor Selection and Amplification Technology (R-SAT). In this screen the thromboxane A2α receptor (TPαR) was the only receptor which significantly enhanced the AngII-mediated response. The TPαR-mediated enhancement of AngII signaling was significantly reduced when a signaling deficient receptor mutant (TPαR R130V) was co-expressed instead of the wild-type TPαR, and was completely blocked both by TPαR antagonists and COX inhibitors inhibiting formation of thromboxane A2 (TXA2). Conclusions/Significance We found a functional enhancement of AT1R only when co-expressed with TPαR, but not with 122 other 7TM receptors. In addition, the TPαR must be functionally active, indicating the AT1R enhancement is mediated by a paracrine mechanism. Since we only found one receptor enhancing AT1R potency, our results suggest that functional augmentation through 7TM receptor cross-talk is a rare event that may require specific conditions to occur.
Collapse
Affiliation(s)
- Jonas Tind Hansen
- Laboratory for Molecular Cardiology, Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Arnolds KL, Lares AP, Spencer JV. The US27 gene product of human cytomegalovirus enhances signaling of host chemokine receptor CXCR4. Virology 2013; 439:122-31. [PMID: 23490053 DOI: 10.1016/j.virol.2013.02.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 12/12/2012] [Accepted: 02/12/2013] [Indexed: 01/09/2023]
Abstract
Human cytomegalovirus (HCMV) is a member of the Herpesviridae family that manipulates host immune responses and establishes life-long latent infection, in part through mimicry of cytokines, chemokines, and chemokine receptors. The HCMV US27 gene product is a putative chemokine receptor with no known ligands. We generated a stable US27 cell line to screen for chemokine ligands but unexpectedly found that US27 potentiated the activity of an endogenous human chemokine receptor, CXCR4. Cells expressing both US27 and CXCR4 exhibited greater calcium mobilization and enhanced chemotaxis in response to CXCL12/SDF-1α than controls. Quantitative RT-PCR revealed a significant increase in CXCR4 expression when US27 was present, and elevated CXCR4 receptor levels were detected via flow cytometry, western blot, and immunofluorescence microscopy. Potentiation of CXCR4 signaling by US27 could represent a novel strategy by which HCMV targets virus-infected cells to the bone marrow in order to expand the reservoir of latently infected cells.
Collapse
Affiliation(s)
- Kathleen L Arnolds
- Department of Biology, University of San Francisco, San Francisco, California 94117, USA
| | | | | |
Collapse
|
33
|
Franco R, Martínez-Pinilla E, Ricobaraza A, McCormick PJ. Challenges in the development of heteromer-GPCR-based drugs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:143-62. [PMID: 23663968 DOI: 10.1016/b978-0-12-386931-9.00006-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
G-protein-coupled receptors are targets of a variety of diseases. Drug screening has been classically performed assuming the occurrence of monomeric receptors. As more and more receptor heteromers are identified, the challenge is now to develop screening assays to select heteromer-specific drugs. These drugs may, for instance, be able to interact preferentially with prerather than with postsynaptic receptors. Heteromer-based drug discovery opens new perspectives in both Academic pursuits and for the Pharmaceutical industry.
Collapse
Affiliation(s)
- Rafael Franco
- Applied Medical Research Center (CIMA), University of Navarra, Pamplona, Spain
| | | | | | | |
Collapse
|
34
|
Johnstone EKM, Pfleger KDG. Receptor-Heteromer Investigation Technology and its application using BRET. Front Endocrinol (Lausanne) 2012; 3:101. [PMID: 22936924 PMCID: PMC3424490 DOI: 10.3389/fendo.2012.00101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/04/2012] [Indexed: 01/08/2023] Open
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.
Collapse
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
| |
Collapse
|
35
|
Mustafa S, See HB, Seeber RM, Armstrong SP, White CW, Ventura S, Ayoub MA, Pfleger KDG. Identification and profiling of novel α1A-adrenoceptor-CXC chemokine receptor 2 heteromer. J Biol Chem 2012; 287:12952-65. [PMID: 22371491 PMCID: PMC3340001 DOI: 10.1074/jbc.m111.322834] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 02/20/2012] [Indexed: 01/14/2023] Open
Abstract
We have provided the first evidence for specific heteromerization between the α(1A)-adrenoceptor (α(1A)AR) and CXC chemokine receptor 2 (CXCR2) in live cells. α(1A)AR and CXCR2 are both expressed in areas such as the stromal smooth muscle layer of the prostate. By utilizing the G protein-coupled receptor (GPCR) heteromer identification technology on the live cell-based bioluminescence resonance energy transfer (BRET) assay platform, our studies in human embryonic kidney 293 cells have identified norepinephrine-dependent β-arrestin recruitment that was in turn dependent upon co-expression of α(1A)AR with CXCR2. These findings have been supported by co-localization observed using confocal microscopy. This norepinephrine-dependent β-arrestin recruitment was inhibited not only by the α(1)AR antagonist Terazosin but also by the CXCR2-specific allosteric inverse agonist SB265610. Furthermore, Labetalol, which is marketed for hypertension as a nonselective β-adrenoceptor antagonist with α(1)AR antagonist properties, was identified as a heteromer-specific-biased agonist exhibiting partial agonism for inositol phosphate production but essentially full agonism for β-arrestin recruitment at the α(1A)AR-CXCR2 heteromer. Finally, bioluminescence resonance energy transfer studies with both receptors tagged suggest that α(1A)AR-CXCR2 heteromerization occurs constitutively and is not modulated by ligand. These findings support the concept of GPCR heteromer complexes exhibiting distinct pharmacology, thereby providing additional mechanisms through which GPCRs can potentially achieve their diverse biological functions. This has important implications for the use and future development of pharmaceuticals targeting these receptors.
Collapse
MESH Headings
- Adrenergic alpha-1 Receptor Antagonists/pharmacology
- Adrenergic alpha-Agonists/pharmacology
- Allosteric Regulation/physiology
- Animals
- Arrestins/metabolism
- CHO Cells
- Chemokines/metabolism
- Cricetinae
- HEK293 Cells
- Humans
- Inositol Phosphates/metabolism
- Labetalol/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Norepinephrine/pharmacology
- Prazosin/analogs & derivatives
- Prazosin/pharmacology
- Prostate/metabolism
- Protein Structure, Quaternary
- Receptors, Adrenergic, alpha-1/chemistry
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Interleukin-8B/chemistry
- Receptors, Interleukin-8B/metabolism
- beta-Arrestins
Collapse
Affiliation(s)
- Sanam Mustafa
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
| | - Heng B. See
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
| | - Ruth M. Seeber
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
| | - Stephen P. Armstrong
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
| | - Carl W. White
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052 and
| | - Sabatino Ventura
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052 and
| | - Mohammed Akli Ayoub
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
| | - Kevin D. G. Pfleger
- From the Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia 6009
- Dimerix Bioscience Pty Ltd, Nedlands, Perth, Western Australia 6009, Australia
| |
Collapse
|
36
|
Dacres H, Michie M, Trowell SC. Comparison of enhanced bioluminescence energy transfer donors for protease biosensors. Anal Biochem 2012; 424:206-10. [PMID: 22387387 DOI: 10.1016/j.ab.2012.02.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/17/2012] [Accepted: 02/22/2012] [Indexed: 11/26/2022]
Abstract
Bioluminescence energy transfer (BRET) is a powerful tool for the study of protein-protein interactions and conformational changes within proteins. We directly compared two recently developed variants of Renilla luciferase (RLuc), RLuc2 and RLuc8, as BRET donors using an in vitro thrombin assay. The comparison was carried out by placing a thrombin-specific cleavage sequence between the donor luciferase and a green fluorescent protein (GFP(2)) acceptor. Substitution of native RLuc with the RLuc mutants, RLuc2 and 8, in a BRET(2) fusion protein increased the light output by a factor of ~10. Substitution of native RLuc with either of the RLuc mutants resulted in a decrease in BRET(2) ratio by a factor of ~2 when BRET(2) components were separated by the thrombin cleavage sequence. BRET(2) ratios changed by factors of 18.8±1.2 and 18.2±0.4 for GFP(2)-RG-RLuc2 and GFP(2)-RG-RLuc8 fusion proteins, respectively, on thrombin cleavage compared to 28.8±0.20 for GFP(2)-RG-RLuc. The detection limits for thrombin were 0.23 and 0.26 nM for RLuc2 and RLuc8 BRET(2) systems, respectively, and 15 pM for GFP(2)-RG-RLuc. However, overall, the mutant BRET systems remain more sensitive than FRET and brighter than standard BRET(2).
Collapse
Affiliation(s)
- Helen Dacres
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT 2601, Australia.
| | | | | |
Collapse
|
37
|
Drinovec L, Kubale V, Nøhr Larsen J, Vrecl M. Mathematical models for quantitative assessment of bioluminescence resonance energy transfer: application to seven transmembrane receptors oligomerization. Front Endocrinol (Lausanne) 2012; 3:104. [PMID: 22973259 PMCID: PMC3428587 DOI: 10.3389/fendo.2012.00104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/08/2012] [Indexed: 11/24/2022] Open
Abstract
The idea that seven transmembrane receptors (7TMRs; also designated G-protein coupled receptors, GPCRs) might form dimers or higher order oligomeric complexes was formulated more than 20 years ago and has been intensively studied since then. In the last decade, bioluminescence resonance energy transfer (BRET) has been one of the most frequently used biophysical methods for studying 7TMRs oligomerization. This technique enables monitoring physical interactions between protein partners in living cells fused to donor and acceptor moieties. It relies on non-radiative transfer of energy between donor and acceptor, depending on their intermolecular distance (1-10 nm) and relative orientation. Results derived from BRET-based techniques are very persuasive; however, they need appropriate controls and critical interpretation. To overcome concerns about the specificity of BRET-derived results, a set of experiments has been proposed, including negative control with a non-interacting receptor or protein, BRET dilution, saturation, and competition assays. This article presents the theoretical background behind BRET assays, then outlines mathematical models for quantitative interpretation of BRET saturation and competition assay results, gives examples of their utilization and discusses the possibilities of quantitative analysis of data generated with other RET-based techniques.
Collapse
|
38
|
Roed SN, Orgaard A, Jorgensen R, De Meyts P. Receptor oligomerization in family B1 of G-protein-coupled receptors: focus on BRET investigations and the link between GPCR oligomerization and binding cooperativity. Front Endocrinol (Lausanne) 2012; 3:62. [PMID: 22649424 PMCID: PMC3355942 DOI: 10.3389/fendo.2012.00062] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/20/2012] [Indexed: 11/13/2022] Open
Abstract
The superfamily of the seven transmembrane G-protein-coupled receptors (7TM/GPCRs) is the largest family of membrane-associated receptors. GPCRs are involved in the pathophysiology of numerous human diseases, and they constitute an estimated 30-40% of all drug targets. During the last two decades, GPCR oligomerization has been extensively studied using methods like bioluminescence resonance energy transfer (BRET) and today, receptor-receptor interactions within the GPCR superfamily is a well-established phenomenon. Evidence of the impact of GPCR oligomerization on, e.g., ligand binding, receptor expression, and signal transduction indicates the physiological and pharmacological importance of these receptor interactions. In contrast to the larger and more thoroughly studied GPCR subfamilies A and C, the B1 subfamily is small and comprises only 15 members, including, e.g., the secretin receptor, the glucagon receptor, and the receptors for parathyroid hormone (PTHR1 and PTHR2). The dysregulation of several family B1 receptors is involved in diseases, such as diabetes, chronic inflammation, and osteoporosis which underlines the pathophysiological importance of this GPCR subfamily. In spite of this, investigation of family B1 receptor oligomerization and especially its pharmacological importance is still at an early stage. Even though GPCR oligomerization is a well-established phenomenon, there is a need for more investigations providing a direct link between these interactions and receptor functionality in family B1 GPCRs. One example of the functional effects of GPCR oligomerization is the facilitation of allosterism including cooperativity in ligand binding to GPCRs. Here, we review the currently available data on family B1 GPCR homo- and heteromerization, mainly based on BRET investigations. Furthermore, we cover the functional influence of oligomerization on ligand binding as well as the link between oligomerization and binding cooperativity.
Collapse
|
39
|
Couturier C, Deprez B. Setting Up a Bioluminescence Resonance Energy Transfer High throughput Screening Assay to Search for Protein/Protein Interaction Inhibitors in Mammalian Cells. Front Endocrinol (Lausanne) 2012; 3:100. [PMID: 22973258 PMCID: PMC3438444 DOI: 10.3389/fendo.2012.00100] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 07/31/2012] [Indexed: 12/14/2022] Open
Abstract
Each step of the cell life and its response or adaptation to its environment are mediated by a network of protein/protein interactions termed "interactome." Our knowledge of this network keeps growing due to the development of sensitive techniques devoted to study these interactions. The bioluminescence resonance energy transfer (BRET) technique was primarily developed to allow the dynamic monitoring of protein/protein interactions (PPI) in living cells, and has widely been used to study receptor activation by intra- or extra-molecular conformational changes within receptors and activated complexes in mammal cells. Some interactions are described as crucial in human pathological processes, and a new class of drugs targeting them has recently emerged. The BRET method is well suited to identify inhibitors of PPI and here is described why and how to set up and optimize a high throughput screening assay based on BRET to search for such inhibitory compounds. The different parameters to take into account when developing such BRET assays in mammal cells are reviewed to give general guidelines: considerations on the targeted interaction, choice of BRET version, inducibility of the interaction, kinetic of the monitored interaction, and of the BRET reading, influence of substrate concentration, number of cells and medium composition used on the Z' factor, and expected interferences from colored or fluorescent compounds.
Collapse
Affiliation(s)
- Cyril Couturier
- Univ Lille Nord de FranceLille, France
- INSERM U761, Biostructures and Drug DiscoveryLille, France
- Université du Droit et de la Santé de LilleLille, France
- Institut Pasteur LilleLille, France
- Pôle de Recherche Interdisciplinaire sur le MédicamentLille, France
- *Correspondence: Cyril Couturier, UMR 761, Biostructure and Drug Discovery, Institut Pasteur de Lille, Université Lille 2, 1 rue du Pr Calmette, 59000 Lille, France. e-mail:
| | - Benoit Deprez
- Univ Lille Nord de FranceLille, France
- INSERM U761, Biostructures and Drug DiscoveryLille, France
- Université du Droit et de la Santé de LilleLille, France
- Institut Pasteur LilleLille, France
- Pôle de Recherche Interdisciplinaire sur le MédicamentLille, France
| |
Collapse
|
40
|
Trinquet E, Bouhelal R, Dietz M. Monitoring Gq-coupled receptor response through inositol phosphate quantification with the IP-One assay. Expert Opin Drug Discov 2011; 6:981-94. [DOI: 10.1517/17460441.2011.608658] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
41
|
Porrello ER, Pfleger KDG, Seeber RM, Qian H, Oro C, Abogadie F, Delbridge LMD, Thomas WG. Heteromerization of angiotensin receptors changes trafficking and arrestin recruitment profiles. Cell Signal 2011; 23:1767-76. [PMID: 21740964 DOI: 10.1016/j.cellsig.2011.06.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 05/29/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
Abstract
The cardiovascular hormone angiotensin II (AngII) exerts its actions via two G protein-coupled receptor (GPCR) subtypes, AT(1) and AT(2), which often display antagonistic functions. Methodological constraints have so far precluded detailed analyses of the ligand-dependency, cellular localization, and functional relevance of AngII receptor interactions in live cells. In this study, we utilize a protein-fragment complementation assay (PCA) and GPCR-Heteromer Identification Technology (GPCR-HIT) to provide the first detailed investigation of the ligand-dependency and cellular localization of AngII receptor interactions in human embryonic kidney 293 cells. Fluorescent-tagged receptor constructs for PCA and GPCR-HIT displayed normal affinity and selectivity for AngII (AT(1): IC(50)=1.0-1.6nM; AT(2): IC(50)=2.0-3.0nM). Well-characterized angiotensin receptor interactions were used as positive and negative controls to demonstrate the sensitivity and specificity of these fluorescence-based assays. We report that AT(1)-AT(2) receptor heteromers form constitutively, are localized to the plasma membrane and perinuclear compartments, and do not internalize following AngII stimulation despite arrestin being recruited specifically to the heteromer. Our findings using novel fluorescence-based technologies reveal a previously unrecognized mechanism of angiotensin receptor cross-talk involving cross-inhibition of AT(1) receptor internalization through heteromerization with the AT(2) receptor subtype.
Collapse
Affiliation(s)
- Enzo R Porrello
- Department of Physiology, The University of Melbourne, Victoria 3010, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Mustafa S, Pfleger KDG. G protein-coupled receptor heteromer identification technology: identification and profiling of GPCR heteromers. ACTA ACUST UNITED AC 2011; 16:285-91. [PMID: 21764024 DOI: 10.1016/j.jala.2011.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Indexed: 10/18/2022]
Abstract
Traditionally, G protein-coupled receptors (GPCRs) were thought to function as monomeric units activating linear signaling pathways to reach a single functional response. However, it is now recognized that GPCRs can exist as higher order structures, such as homomers or heteromers. The potential for unique pharmacology attributed to these GPCR complexes has opened up the possibility of a new class of targets that can be exploited for drug discovery. In this innovation brief, a novel technology developed to identify and profile GPCR heteromers and their ligands will be reviewed.
Collapse
Affiliation(s)
- Sanam Mustafa
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | | |
Collapse
|
43
|
Dalrymple MB, Jaeger WC, Eidne KA, Pfleger KDG. Temporal profiling of orexin receptor-arrestin-ubiquitin complexes reveals differences between receptor subtypes. J Biol Chem 2011; 286:16726-33. [PMID: 21378163 PMCID: PMC3089514 DOI: 10.1074/jbc.m111.223537] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Orexin G protein-coupled receptors (OxRs) and their cognate agonists have been implicated in a number of disorders since their recent discovery, ranging from narcolepsy to formation of addictive behavior. Bioluminescence resonance energy transfer assays of agonist-occupied OxRs provided evidence for a strong dose-dependent interaction with both trafficking proteins β-arrestin 1 and 2 that required unusually high agonist concentrations compared with inositol phosphate signaling. This appears to be reflected in functional differences in potency with respect to orexin A (OxA) and OxR2-dependent ERK1/2 phosphorylation after 90 min compared with 2 min, potentially consistent with β-arrestin-mediated versus G protein-mediated signaling, respectively. Furthermore, extended bioluminescence resonance energy transfer kinetic data monitoring OxA-dependent receptor-β-arrestin and β-arrestin-ubiquitin proximity suggested subtype-specific differences in receptor trafficking, with OxR2 activation resulting in more sustained receptor-β-arrestin-ubiquitin complex formation than elicited by OxR1 activation. Enzyme-linked immunosorbent assay (ELISA) data also revealed that OxR1 underwent significantly more rapid recycling compared with OxR2. Finally, we have observed sustained OxA-dependent ERK1/2 phosphorylation in the presence of OxR2 compared with OxR1. Although both OxR subtypes could be classified as class B receptors for β-arrestin usage based on the initial strength of interaction with both β-arrestins, our temporal profiling revealed tangible differences between OxR subtypes. Consequently, OxR1 appears to fit uneasily into the commonly used β-arrestin classification scheme. More importantly, it is hoped that this improved profiling capability, enabling the subtleties of protein complex formation, stability, and duration to be assessed in live cells, will help unlock the therapeutic potential of targeting these receptors.
Collapse
Affiliation(s)
- Matthew B Dalrymple
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Perth, Western Australia 6009, Australia
| | | | | | | |
Collapse
|
44
|
Kocan M, Dalrymple MB, Seeber RM, Feldman BJ, Pfleger KDG. Enhanced BRET Technology for the Monitoring of Agonist-Induced and Agonist-Independent Interactions between GPCRs and β-Arrestins. Front Endocrinol (Lausanne) 2010; 1:12. [PMID: 22654789 PMCID: PMC3356007 DOI: 10.3389/fendo.2010.00012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Accepted: 12/22/2011] [Indexed: 11/23/2022] Open
Abstract
The bioluminescence resonance energy transfer (BRET) technique has become extremely valuable for the real-time monitoring of protein-protein interactions in live cells. This method is highly amenable to the detection of G protein-coupled receptor (GPCR) interactions with proteins critical for regulating their function, such as β-arrestins. Of particular interest to endocrinologists is the ability to monitor interactions involving endocrine receptors, such as orexin receptor 2 or vasopressin type II receptor. The BRET method utilizes heterologous co-expression of fusion proteins linking one protein of interest (GPCR) to a bioluminescent donor enzyme, a variant of Renilla luciferase, and a second protein of interest (β-arrestin) to an acceptor fluorophore. If in close proximity, energy resulting from oxidation of the coelenterazine substrate by the donor will transfer to the acceptor, which in turn fluoresces. Using novel luciferase constructs, we were able to monitor interactions not detectable using less sensitive BRET combinations in the same configuration. In particular, we were able to show receptor/β-arrestin interactions in an agonist-independent manner using Rluc8-tagged mutant receptors, in contrast to when using Rluc. Therefore, the enhanced BRET methodology has not only enabled live cell compound screening as we have recently published, it now provides a new level of sensitivity for monitoring specific transient, weak or hardly detectable protein-protein complexes, including agonist-independent GPCR/β-arrestin interactions. This has important implications for the use of BRET technologies in endocrine drug discovery programs as well as academic research.
Collapse
Affiliation(s)
- Martina Kocan
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western AustraliaPerth, WA, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash UniversityParkville, VIC, Australia
| | - Matthew B. Dalrymple
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western AustraliaPerth, WA, Australia
| | - Ruth M. Seeber
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western AustraliaPerth, WA, Australia
| | - Brian J. Feldman
- Pediatric Endocrinology, Department of Pediatrics, Stanford UniversityStanford, CA, USA
| | - Kevin D. G. Pfleger
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western AustraliaPerth, WA, Australia
- *Correspondence: Kevin D. G. Pfleger, Western Australian Institute for Medical Research, Queen Elizabeth II Medical Centre, Ground Floor, B Block, Hospital Avenue, Nedlands, WA 6009, Australia. e-mail:
| |
Collapse
|