1
|
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
|
2
|
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
|
3
|
Jacobsen JHW, Hutchinson MR, Mustafa S. Drug addiction: targeting dynamic neuroimmune receptor interactions as a potential therapeutic strategy. Curr Opin Pharmacol 2016; 26:131-7. [DOI: 10.1016/j.coph.2015.10.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 01/29/2023]
|
4
|
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
|
5
|
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
|
6
|
Thomas J, Mustafa S, Johnson J, Nicotra L, Hutchinson M. The relationship between opioids and immune signalling in the spinal cord. Handb Exp Pharmacol 2015; 227:207-238. [PMID: 25846621 DOI: 10.1007/978-3-662-46450-2_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Opioids are considered the gold standard for the treatment of moderate to severe pain. However, heterogeneity in analgesic efficacy, poor potency and side effects are associated with opioid use, resulting in dose limitations and suboptimal pain management. Traditionally thought to exhibit their analgesic actions via the activation of the neuronal G-protein-coupled opioid receptors, it is now widely accepted that neuronal activity of opioids cannot fully explain the initiation and maintenance of opioid tolerance, hyperalgesia and allodynia. In this review we will highlight the evidence supporting the role of non-neuronal mechanisms in opioid signalling, paying particular attention to the relationship of opioids and immune signalling.
Collapse
Affiliation(s)
- Jacob Thomas
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, Adelaide, Australia,
| | | | | | | | | |
Collapse
|
7
|
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
|
8
|
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
|
9
|
Brown RM, Mustafa S, Ayoub MA, Dodd PR, Pfleger KDG, Lawrence AJ. mGlu5 Receptor Functional Interactions and Addiction. Front Pharmacol 2012; 3:84. [PMID: 22586398 PMCID: PMC3345582 DOI: 10.3389/fphar.2012.00084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/16/2012] [Indexed: 12/22/2022] Open
Abstract
The idea of “receptor mosaics” is that proteins may form complex and dynamic networks with respect to time and composition. These have the potential to markedly expand the diversity and specificity of G protein-coupled receptors (GPCR) signaling, particularly in neural cells, where a few key receptors have been implicated in many neurological and psychiatric disorders, including addiction. Metabotropic glutamate type 5 receptors (mGlu5) can form complexes with other GPCRs, including adenosine A2A and dopamine D2 receptors. mGlu5-containing complexes have been reported in the striatum, a brain region critical for mediating the rewarding and incentive motivational properties of drugs of abuse. mGlu5-containing complexes and/or downstream interactions between divergent receptors may play roles in addiction–relevant behaviors. Interactions between mGlu5 receptors and other GPCRs can regulate the rewarding and conditioned effects of drugs as well as drug-seeking behaviors. mGlu5 complexes may influence striatal function, including GABAergic output of striatopallidal neurons and glutamatergic input from corticostriatal afferents. Given their discrete localization, mGlu5-[non-mGlu5] receptor interactions and/or mGlu5-containing complexes may minimize off-target effects and thus provide a novel avenue for drug discovery. The therapeutic targeting of receptor–receptor functional interactions and/or receptor mosaics in a tissue specific or temporal manner (for example, a sub-population of receptors in a “pathological state”) might reduce detrimental side effects that may otherwise impair vital brain functions.
Collapse
Affiliation(s)
- Robyn M Brown
- Addiction Neuroscience, Behavioural Neuroscience, Florey Neuroscience Institutes, University of Melbourne Parkville, VIC, Australia
| | | | | | | | | | | |
Collapse
|
10
|
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
|
11
|
Tadagaki K, Jockers R, Kamal M. History and biological significance of GPCR heteromerization in the neuroendocrine system. Neuroendocrinology 2012; 95:223-31. [PMID: 22156565 DOI: 10.1159/000330000] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/07/2011] [Indexed: 12/18/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute a large family of seven transmembrane proteins that regulate major cellular functions. The important role of GPCRs in the neuroendocrine system is outlined by the great interest of pharmaceutical companies in developing new drugs targeting these receptors. GPCRs exist as monomers, but can also be organized in oligomeric structures composed of either homo- or heteromers. GPCR heteromerization may play an important role in modulating and fine-tuning GPCR function and signaling. The literature reports many examples of GPCR heteromers in vitro raising the question of the physiological relevance of these complexes in tissues. Considerable efforts are currently being directed towards conclusive evidence for the existence of GPCRs heteromers in vivo, a crucial step for the validation of the concept of GPCR heteromerization and future drug development. The present review will give a brief history of GPCR oligomerization and emphasize the importance and physiological relevance of GPCR heteromerization by discussing key examples of GPCR couples.
Collapse
Affiliation(s)
- Kenjiro Tadagaki
- Inserm, U1016, Institut Cochin, CNRS UMR 8104, Université Paris Descartes, Paris, France
| | | | | |
Collapse
|
12
|
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
|
13
|
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
|
14
|
See HB, Seeber RM, Kocan M, Eidne KA, Pfleger KDG. Application of G protein-coupled receptor-heteromer identification technology to monitor β-arrestin recruitment to G protein-coupled receptor heteromers. Assay Drug Dev Technol 2010; 9:21-30. [PMID: 21133678 DOI: 10.1089/adt.2010.0336] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Understanding the role of G protein-coupled receptor (GPCR; also known as a 7 transmembrane receptor) heteromerization in the physiology and pathophysiology of cellular function has now become a major research focus. However, there is currently a lack of cell-based assays capable of profiling the specific functional consequences of heteromerization in a ligand-dependent manner. Understanding the pharmacology specifically associated with heteromer function in contrast to monomer or homomer function enables the so-called biochemical fingerprints of the receptor heteromer to be ascertained. This is the first step in establishing the physiological relevance of heteromerization, the goal of everyone in the field, as these fingerprints can then be utilized in future endeavors to elucidate heteromer function in native tissues. The simple, robust, ligand-dependent methodology described in this study utilizes a novel configuration of components of a proximity-based reporter system. This is exemplified by the use of bioluminescence resonance energy transfer due to the advantages of real-time live cell monitoring of proximity specifically between the heteromer complex and a protein that is recruited in a ligand-dependent manner, in this case, β-arrestin 2. Further, the demonstration of Z'-factor values in excess of 0.6 shows the potential of the method for screening compounds for heteromer-selective or biased activity. Three previously characterized GPCR heteromers, the chemokine receptor heteromers CCR2-CCR5 and CCR2-CXCR4, as well as the angiotensin II receptor type 1-bradykinin receptor type 2 heteromer, have been used to illustrate the profiling capability and specificity of the GPCR heteromer identification technology.
Collapse
Affiliation(s)
- Heng B See
- Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Hospital Avenue, Nedlands, WA 6009, Australia
| | | | | | | | | |
Collapse
|