1
|
Hong JM, Lee JW, Seen DS, Jeong JY, Huh WK. LPA1-mediated inhibition of CXCR4 attenuates CXCL12-induced signaling and cell migration. Cell Commun Signal 2023; 21:257. [PMID: 37749552 PMCID: PMC10518940 DOI: 10.1186/s12964-023-01261-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 08/09/2023] [Indexed: 09/27/2023] Open
Abstract
BACKGROUND G protein-coupled receptor heteromerization is believed to exert dynamic regulatory impact on signal transduction. CXC chemokine receptor 4 (CXCR4) and its ligand CXCL12, both of which are overexpressed in many cancers, play a pivotal role in metastasis. Likewise, lysophosphatidic acid receptor 1 (LPA1) is implicated in cancer cell proliferation and migration. In our preliminary study, we identified LPA1 as a prospective CXCR4 interactor. In the present study, we investigated in detail the formation of the CXCR4-LPA1 heteromer and characterized the unique molecular features and function of this heteromer. METHODS We employed bimolecular fluorescence complementation, bioluminescence resonance energy transfer, and proximity ligation assays to demonstrate heteromerization between CXCR4 and LPA1. To elucidate the distinctive molecular characteristics and functional implications of the CXCR4-LPA1 heteromer, we performed various assays, including cAMP, BRET for G protein activation, β-arrestin recruitment, ligand binding, and transwell migration assays. RESULTS We observed that CXCR4 forms heteromers with LPA1 in recombinant HEK293A cells and the human breast cancer cell line MDA-MB-231. Coexpression of LPA1 with CXCR4 reduced CXCL12-mediated cAMP inhibition, ERK activation, Gαi/o activation, and β-arrestin recruitment, while CXCL12 binding to CXCR4 remained unaffected. In contrast, CXCR4 had no impact on LPA1-mediated signaling. The addition of lysophosphatidic acid (LPA) further hindered CXCL12-induced Gαi/o recruitment to CXCR4. LPA or alkyl-OMPT inhibited CXCL12-induced migration in various cancer cells that endogenously express both CXCR4 and LPA1. Conversely, CXCL12-induced calcium signaling and migration were increased in LPAR1 knockout cells, and LPA1-selective antagonists enhanced CXCL12-induced Gαi/o signaling and cell migration in the parental MDA-MB-231 cells but not in LPA1-deficient cells. Ultimately, complete inhibition of cell migration toward CXCL12 and alkyl-OMPT was only achieved in the presence of both CXCR4 and LPA1 antagonists. CONCLUSIONS The presence and impact of CXCR4-LPA1 heteromers on CXCL12-induced signaling and cell migration have been evidenced across various cell lines. This discovery provides crucial insights into a valuable regulatory mechanism of CXCR4 through heteromerization. Moreover, our findings propose a therapeutic potential in combined CXCR4 and LPA1 inhibitors for cancer and inflammatory diseases associated with these receptors, simultaneously raising concerns about the use of LPA1 antagonists alone for such conditions. Video Abstract.
Collapse
Affiliation(s)
- Jong Min Hong
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jin-Woo Lee
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Dong-Seung Seen
- GPCR Therapeutics Inc, Gwanak-Gu, Seoul, 08790, Republic of Korea
| | - Jae-Yeon Jeong
- GPCR Therapeutics Inc, Gwanak-Gu, Seoul, 08790, Republic of Korea.
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
- Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea.
| |
Collapse
|
2
|
Lazzaretti C, Simoni M, Casarini L, Paradiso E. Allosteric modulation of gonadotropin receptors. Front Endocrinol (Lausanne) 2023; 14:1179079. [PMID: 37305033 PMCID: PMC10248450 DOI: 10.3389/fendo.2023.1179079] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/12/2023] [Indexed: 06/13/2023] Open
Abstract
Gonadotropins regulate reproductive functions by binding to G protein-coupled receptors (FSHR and LHCGR) expressed in the gonads. They activate multiple, cell-specific signalling pathways, consisting of ligand-dependent intracellular events. Signalling cascades may be modulated by synthetic compounds which bind allosteric sites of FSHR and LHCGR or by membrane receptor interactions. Despite the hormone binding to the orthosteric site, allosteric ligands, and receptor heteromerizations may reshape intracellular signalling pattern. These molecules act as positive, negative, or neutral allosteric modulators, as well as non-competitive or inverse agonist ligands, providing a set of new compounds of a different nature and with unique pharmacological characteristics. Gonadotropin receptor allosteric modulation is gathering increasing interest from the scientific community and may be potentially exploited for clinical purposes. This review summarizes the current knowledge on gonadotropin receptor allosteric modulation and their potential, clinical use.
Collapse
Affiliation(s)
- Clara Lazzaretti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
- Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Baggiovara Hospital, Modena, Italy
| | - Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Elia Paradiso
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
| |
Collapse
|
3
|
Guo S, Zhao T, Yun Y, Xie X. Recent Progress in Assays for GPCR Drug Discovery. Am J Physiol Cell Physiol 2022; 323:C583-C594. [PMID: 35816640 DOI: 10.1152/ajpcell.00464.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
G-protein coupled receptors (GPCRs), also known as 7 transmembrane receptors, are the largest family of cell surface receptors in eukaryotes. There are ~800 GPCRs in human, regulating diverse physiological processes. GPCRs are the most intensively studied drug targets. Drugs that target GPCRs account for about a quarter of the global market share of therapeutic drugs. Therefore, to develop physiologically relevant and robust assays to search new GPCR ligands or modulators remain the major focus of drug discovery research worldwide. Early functional GPCR assays are mainly depend on the measurement of G protein-mediated second messenger generation. Recent development in GPCR biology indicate the signaling of these receptors is much more complex than the oversimplified classical view. GPCRs have been found to activate multiple G proteins simultaneously and induce b-arrestin-mediated signaling. GPCRs have also been found to interacte with other cytosolic scaffolding proteins and form dimer or heteromer with GPCRs or other transmembrane proteins. Here we mainly discuss technologies focused on detecting protein-protein interactions, such as FRET/BRET, NanoBiT, Tango, etc, and their applications in measuring GPCRs interacting with various signaling partners. In the final part, we also discuss the species differences in GPCRs when using animal models to study the in vivofunctions of GPCR ligands, and possible ways to solve this problem with modern genetic tools.
Collapse
Affiliation(s)
- Shimeng Guo
- grid.419093.6Shanghai Institute of Materia Medica, Shanghai, China
| | - Tingting Zhao
- grid.419093.6Shanghai Institute of Materia Medica, Shanghai, China
| | - Ying Yun
- grid.419093.6Shanghai Institute of Materia Medica, Shanghai, China
| | - Xin Xie
- grid.419093.6Shanghai Institute of Materia Medica, Shanghai, China
| |
Collapse
|
4
|
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
|
5
|
Kobayashi Y. New perspectives on GPCRs: GPCR heterodimer formation (melanocortin receptor) and GPCR on primary cilia (melanin concentrating hormone receptor). Gen Comp Endocrinol 2020; 293:113474. [PMID: 32240710 DOI: 10.1016/j.ygcen.2020.113474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/18/2020] [Accepted: 03/28/2020] [Indexed: 11/13/2022]
Abstract
GPCRs are the largest family of receptors accounting for about 30% of the current drug targets. However, it is difficult to fully elucidate the mechanisms regulating intracellular GPCR signal regulation. It is thus important to consider and investigate GPCRs with respect to endogenous situations. Our group has been investigating GPCRs involved in body color (teleost and amphibian) and eating (vertebrate). Here, I review two independent GPCR systems (heterodimer formation and primary ciliated GPCR) that can be breakthroughs in GPCR research. In teleosts, MCRs form heterodimers, which significantly reduce their affinity for acetylated ligands. In mammals, MCHR1 is localized in the ciliary membrane and shortens the length of the primary cilia through a unique signal from the ciliary membrane. Considering these two new GPCR concepts is expected to advance the overall view of the GPCR system.
Collapse
Affiliation(s)
- Yuki Kobayashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan.
| |
Collapse
|
6
|
Esteban PF, Garcia-Ovejero D, Paniagua-Torija B, Moreno-Luna R, Arredondo LF, Zimmer A, Arevalo-Martin A, Molina-Holgado E. Revisiting CB1 cannabinoid receptor detection and the exploration of its interacting partners. J Neurosci Methods 2020; 337:108680. [DOI: 10.1016/j.jneumeth.2020.108680] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 12/31/2022]
|
7
|
Rasineni K, Kubik JL, Casey CA, Kharbanda KK. Inhibition of Ghrelin Activity by Receptor Antagonist [d-Lys-3] GHRP-6 Attenuates Alcohol-Induced Hepatic Steatosis by Regulating Hepatic Lipid Metabolism. Biomolecules 2019; 9:biom9100517. [PMID: 31546643 PMCID: PMC6843513 DOI: 10.3390/biom9100517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 01/13/2023] Open
Abstract
Alcoholic steatosis, characterized by an accumulation of triglycerides in hepatocytes, is one of the earliest pathological changes in the progression of alcoholic liver disease. In our previous study, we showed that alcohol-induced increase in serum ghrelin levels impair insulin secretion from pancreatic β-cells. The consequent reduction in the circulating insulin levels promote adipose-derived fatty acid mobilization to ultimately contribute to hepatic steatosis. In this study, we determined whether inhibition of ghrelin activity in chronic alcohol-fed rats could improve hepatic lipid homeostasis at the pancreas-adipose-liver axis. Adult Wistar rats were fed Lieber-DeCarli control or an ethanol liquid diet for 7 weeks. At 6 weeks, a subset of rats in each group were injected with either saline or ghrelin receptor antagonist, [d-Lys-3] GHRP-6 (DLys; 9 mg/kg body weight) for 5 days and all rats were sacrificed 2 days later. DLys treatment of ethanol rats improved pancreatic insulin secretion, normalized serum insulin levels, and the adipose lipid metabolism, as evidenced by the decreased serum free fatty acids (FFA). DLys treatment of ethanol rats also significantly decreased the circulating FFA uptake, de novo hepatic fatty acid synthesis ultimately attenuating alcoholic steatosis. To summarize, inhibition of ghrelin activity reduced alcoholic steatosis by improving insulin secretion, normalizing serum insulin levels, inhibiting adipose lipolysis, and preventing fatty acid uptake and synthesis in the liver. Our studies provided new insights on the important role of ghrelin in modulating the pancreas-adipose-liver, and promoting adipocyte lipolysis and hepatic steatosis. The findings offer a therapeutic approach of not only preventing alcoholic liver injury but also treating it.
Collapse
Affiliation(s)
- Karuna Rasineni
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Jacy L Kubik
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Kusum K Kharbanda
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| |
Collapse
|
8
|
Rasineni K, Casey CA, Kharbanda KK. Reply to "Letter to Editor: Chronic alcohol exposure alters circulating insulin and ghrelin levels in hepatic steatosis: a translational research perspective". Am J Physiol Gastrointest Liver Physiol 2019; 317:G361-G362. [PMID: 31461305 PMCID: PMC6774088 DOI: 10.1152/ajpgi.00143.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 01/31/2023]
Affiliation(s)
- Karuna Rasineni
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Kusum K Kharbanda
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| |
Collapse
|
9
|
Xue L, Sun Q, Zhao H, Rovira X, Gai S, He Q, Pin JP, Liu J, Rondard P. Rearrangement of the transmembrane domain interfaces associated with the activation of a GPCR hetero-oligomer. Nat Commun 2019; 10:2765. [PMID: 31235691 PMCID: PMC6591306 DOI: 10.1038/s41467-019-10834-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 06/04/2019] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) can integrate extracellular signals via allosteric interactions within dimers and higher-order oligomers. However, the structural bases of these interactions remain unclear. Here, we use the GABAB receptor heterodimer as a model as it forms large complexes in the brain. It is subjected to genetic mutations mainly affecting transmembrane 6 (TM6) and involved in human diseases. By cross-linking, we identify the transmembrane interfaces involved in GABAB1-GABAB2, as well as GABAB1-GABAB1 interactions. Our data are consistent with an oligomer made of a row of GABAB1. We bring evidence that agonist activation induces a concerted rearrangement of the various interfaces. While the GB1-GB2 interface is proposed to involve TM5 in the inactive state, cross-linking of TM6s lead to constitutive activity. These data bring insight for our understanding of the allosteric interaction between GPCRs within oligomers. G protein-coupled receptors (GPCRs), such as GABAB, can integrate extracellular signals via allosteric interactions within dimers and oligomers. Here authors use crosslinking and identify two transmembrane interfaces in GABAB which undergo a concerted rearrangement upon agonist activation.
Collapse
Affiliation(s)
- Li Xue
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Qian Sun
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Han Zhao
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France.,Molecular Photopharmacology Research Group, The Tissue Repair and Regeneration Laboratory, University of Vic - Central University of Catalonia, C. de la Laura, 13, Vic, 08500, Spain
| | - Siyu Gai
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Qianwen He
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France.
| | - Jianfeng Liu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, Université de Montpellier, Montpellier, 34094 Montpellier cedex 05, France
| |
Collapse
|
10
|
Casarini L, Santi D, Simoni M, Potì F. 'Spare' Luteinizing Hormone Receptors: Facts and Fiction. Trends Endocrinol Metab 2018; 29:208-217. [PMID: 29429918 DOI: 10.1016/j.tem.2018.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/16/2018] [Accepted: 01/22/2018] [Indexed: 01/08/2023]
Abstract
It is common opinion that maximal activation of luteinizing hormone (LH)-dependent steroidogenic signal occurs at <1% of human LH/choriogonadotropin (hCG) receptor (LHCGR) occupancy. This effect would be a consequence of an excess of receptors expressed on the surface of theca cells, resulting in a pool of LHCGRs remaining unbound (spare). This concept was borrowed from historical pharmacological studies, when discrepancies between ligand-receptor binding and dose-response curves of cAMP were evaluated by treating mouse or rat Leydig cells with hCG in vitro. Recent findings demonstrated the specificity of LH- and hCG-dependent effects, receptor heterodimerization, and differing behaviors of rodent versus human gonadotropin-responsive cells, which may help to revise the 'spare' LHCGRs concept applied to human ovarian physiology and assisted reproduction.
Collapse
Affiliation(s)
- Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125 Modena, Italy.
| | - Daniele Santi
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Department of Medicine, Endocrinology, Metabolism and Geriatrics, Azienda Ospedaliero-Universitaria di Modena, NOCSAE, Via P. Giardini 1355, 41126 Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125 Modena, Italy; Department of Medicine, Endocrinology, Metabolism and Geriatrics, Azienda Ospedaliero-Universitaria di Modena, NOCSAE, Via P. Giardini 1355, 41126 Modena, Italy
| | - Francesco Potì
- Department of Medicine and Surgery - Unit of Neurosciences, University of Parma, via Volturno 39/F, 43125 Parma, Italy.
| |
Collapse
|
11
|
Wang L, Yuan Y, Chen X, Chen J, Guo Y, Li M, Li C, Pu X. Probing the cooperative mechanism of the μ–δ opioid receptor heterodimer by multiscale simulation. Phys Chem Chem Phys 2018; 20:29969-29982. [DOI: 10.1039/c8cp06652c] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The activation-cooperativity of the μ–δ opioid receptor heterodimer was probed by multiscale simulation coupled with a protein structure network.
Collapse
Affiliation(s)
- Longrong Wang
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| | - Yuan Yuan
- College of Management
- Southwest University for Nationalities
- Chengdu 610041
- P. R. China
| | - Xin Chen
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| | - Jiangfan Chen
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| | - Yanzhi Guo
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| | - Menglong Li
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| | - Chuan Li
- College of Computer Science
- Sichuan University
- Chengdu
- P. R. China
| | - Xuemei Pu
- Faculty of Chemistry
- Sichuan University
- Chengdu
- People's Republic of China
| |
Collapse
|
12
|
Abstract
GPCRs play a pervasive physiological role and, in turn, are the leading target class for pharmaceuticals. Beginning with the determination of the structure of rhodopsin, and dramatically accelerating since the reporting of the first ligand-mediated GPCR X-ray structures, our understanding of the structural and functional characteristics of these proteins has grown dramatically. Deploying this now rapidly emerging information for drug discovery has already been extensively demonstrated through a watershed of studies appearing in numerous scientific reports. Included in these expositions are areas such as sites and characteristics of ligand to GPCR binding, protein activation, effector bias, allosteric mechanisms, dimerization, polypharmacology and others. Computational chemistry studies are demonstrating an increasing role in capitalizing on the structural studies to further advance our understanding of these proteins as well as to drive drug discovery. Such drug discovery activities range from the design of orthosteric site inhibitors through, for example, allosteric modulators, biased ligands, partial agonists and bitopic ligands. Herein, these topics are outlined through specific examples in the hopes of providing a glimpse of the state of the field.
Collapse
|
13
|
Stockmann H, Todorovic V, Richardson PL, Marin V, Scott V, Gerstein C, Lake M, Wang L, Sadhukhan R, Vasudevan A. Cell-Surface Receptor–Ligand Interaction Analysis with Homogeneous Time-Resolved FRET and Metabolic Glycan Engineering: Application to Transmembrane and GPI-Anchored Receptors. J Am Chem Soc 2017; 139:16822-16829. [DOI: 10.1021/jacs.7b09359] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Henning Stockmann
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Viktor Todorovic
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Paul L. Richardson
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Violeta Marin
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Victoria Scott
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Clare Gerstein
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Marc Lake
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Leyu Wang
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Ramkrishna Sadhukhan
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| | - Anil Vasudevan
- AbbVie, Inc., 1 North Waukegan Road, North
Chicago, Illinois 60064, United States
| |
Collapse
|
14
|
Suzuki T. [Hetero-oligomerization and Functional Interaction between Purinergic Receptors Expressed in Platelets to Regulate Platelet Shape Change]. YAKUGAKU ZASSHI 2016; 135:1335-40. [PMID: 26632148 DOI: 10.1248/yakushi.15-00178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenosine and its precursors, ATP and ADP, exert various physiological effects via binding to purinergic receptors. We previously used co-immunoprecipitation, bioluminescence resonance energy transfer (BRET) and immunoelectron microscopy to demonstrate the hetero-oligomerization of purinergic receptor subtypes. Furthermore, pharmacological studies found significant changes in receptor-mediated signaling in human embryonic kidney (HEK) 293T cells co-transfected with these receptors. These findings suggest that heterodimers of purinergic receptors may have distinct pharmacological profiles, possibly due to dimerization-induced conformational changes, further suggesting that hetero-dimerization may be employed to "fine-tune" purinergic receptor signaling. Adenosine A(2A) receptor (A(2A)R), P2Y1 receptor (P2Y1R) and P2Y12 receptor (P2Y12R) are predominantly expressed on human platelets. ADP activates human platelets by stimulating both P2Y1R and P2Y12R, which act sequentially and in concert to achieve complete platelet aggregation. In contrast, adenosine stimulates Gs-coupled A(2A)R, followed by activativation of adenylate cyclase, leading to an increase in intracellular cAMP levels, which potently inhibits platelet activation. We examined the hetero-oligomerization and functional interactions of A(2A)R, P2Y1R, and P2Y12R. In HEK293T cells triply expressing all three receptors, hetero-oligomerization was observed among the three receptors. Additionally, P2Y1R agonist-evoked Ca(2+) signaling was significantly inhibited by co-treatment with an A(2A)R antagonist in HEK293T cells. In human platelets, we identified endogenous A(2A)R/P2Y1R and A(2A)R/P2Y12R heterodimers. We also observed functional Ca(2+)-signaling-related cross-talk similar to those found in HEK293T cells, and found that they appeared to affect platelet shape. These results collectively suggest that intermolecular signal transduction and specific conformational changes occur among components of the hetero-oligomers formed by these three receptors.
Collapse
Affiliation(s)
- Tokiko Suzuki
- Department of Cellular Signaling, Graduate School of Pharmaceutical Sciences, Tohoku University
| |
Collapse
|
15
|
Abstract
Protease signaling in cells elicits multiple physiologically important responses via protease-activated receptors (PARs). There are 4 members of this family of G-protein-coupled receptors (PAR1-4). PARs are activated by proteolysis of the N terminus to reveal a tethered ligand. The rate-limiting step of PAR signaling is determined by the efficiency of proteolysis of the N terminus, which is regulated by allosteric binding sites, cofactors, membrane localization, and receptor dimerization. This ultimately controls the initiation of PAR signaling. In addition, these factors also control the cellular response by directing signaling toward G-protein or β-arrestin pathways. PAR1 signaling on endothelial cells is controlled by the activating protease and heterodimerization with PAR2 or PAR3. As a consequence, the genetic and epigenetic control of PARs and their cofactors in physiologic and pathophysiologic conditions have the potential to influence cellular behavior. Recent studies have uncovered polymorphisms that result in PAR4 sequence variants with altered reactivity that interact to influence platelet response. This further demonstrates how interactions within the plasma membrane can control the physiological output. Understanding the structural rearrangement following PAR activation and how PARs are allosterically controlled within the plasma membrane will determine how best to target this family of receptors therapeutically. The purpose of this article is to review how signaling from PARs is influenced by alternative cleavage sites and the physical interactions within the membrane. Going forward, it will be important to relate the altered signaling to the molecular arrangement of PARs in the cell membrane and to determine how these may be influenced genetically.
Collapse
|
16
|
Franco R, Martínez-Pinilla E, Lanciego JL, Navarro G. Basic Pharmacological and Structural Evidence for Class A G-Protein-Coupled Receptor Heteromerization. Front Pharmacol 2016; 7:76. [PMID: 27065866 PMCID: PMC4815248 DOI: 10.3389/fphar.2016.00076] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/11/2016] [Indexed: 12/25/2022] Open
Abstract
Cell membrane receptors rarely work on isolation, often they form oligomeric complexes with other receptor molecules and they may directly interact with different proteins of the signal transduction machinery. For a variety of reasons, rhodopsin-like class A G-protein-coupled receptors (GPCRs) seem an exception to the general rule of receptor-receptor direct interaction. In fact, controversy surrounds their potential to form homo- hetero-dimers/oligomers with other class A GPCRs; in a sense, the field is going backward instead of forward. This review focuses on the convergent, complementary and telling evidence showing that homo- and heteromers of class A GPCRs exist in transfected cells and, more importantly, in natural sources. It is time to decide between questioning the occurrence of heteromers or, alternatively, facing the vast scientific and technical challenges that class A receptor-dimer/oligomer existence pose to Pharmacology and to Drug Discovery.
Collapse
Affiliation(s)
- Rafael Franco
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biología, Universitat de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain; Institute of Biomedicine, University of BarcelonaBarcelona, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias, Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de OviedoAsturias, Spain; Neurosciences Division, Centre for Applied Medical Research, University of NavarraPamplona, Spain; Instituto de Investigaciones Sanitarias de NavarraPamplona, Spain
| | - José L Lanciego
- Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain; Neurosciences Division, Centre for Applied Medical Research, University of NavarraPamplona, Spain; Instituto de Investigaciones Sanitarias de NavarraPamplona, Spain
| | - Gemma Navarro
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biología, Universitat de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain
| |
Collapse
|
17
|
Aghazadeh Tabrizi M, Baraldi PG, Borea PA, Varani K. Medicinal Chemistry, Pharmacology, and Potential Therapeutic Benefits of Cannabinoid CB2 Receptor Agonists. Chem Rev 2016; 116:519-60. [PMID: 26741146 DOI: 10.1021/acs.chemrev.5b00411] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Mojgan Aghazadeh Tabrizi
- Department of Chemical and Pharmaceutical Sciences and ‡Department of Medical Science, Pharmacology Section, University of Ferrara , Ferrara 44121, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences and ‡Department of Medical Science, Pharmacology Section, University of Ferrara , Ferrara 44121, Italy
| | - Pier Andrea Borea
- Department of Chemical and Pharmaceutical Sciences and ‡Department of Medical Science, Pharmacology Section, University of Ferrara , Ferrara 44121, Italy
| | - Katia Varani
- Department of Chemical and Pharmaceutical Sciences and ‡Department of Medical Science, Pharmacology Section, University of Ferrara , Ferrara 44121, Italy
| |
Collapse
|
18
|
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
|
19
|
Lambert NA, Javitch JA. CrossTalk opposing view: Weighing the evidence for class A GPCR dimers, the jury is still out. J Physiol 2015; 592:2443-5. [PMID: 24931945 DOI: 10.1113/jphysiol.2014.272997] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, GA, 30912-2300, USA
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
| |
Collapse
|
20
|
Xue L, Rovira X, Scholler P, Zhao H, Liu J, Pin JP, Rondard P. Major ligand-induced rearrangement of the heptahelical domain interface in a GPCR dimer. Nat Chem Biol 2015; 11:134-40. [PMID: 25503927 DOI: 10.1038/nchembio.1711] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/14/2014] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are major players in cell communication. Although they form functional monomers, increasing evidence indicates that GPCR dimerization has a critical role in cooperative phenomena that are important for cell signal integration. However, the structural bases of these phenomena remain elusive. Here, using well-characterized receptor dimers, the metabotropic glutamate receptors (mGluRs), we show that structural changes at the dimer interface are linked to receptor activation. We demonstrate that the main dimer interface is formed by transmembrane α helix 4 (TM4) and TM5 in the inactive state and by TM6 in the active state. This major change in the dimer interface is required for receptor activity because locking the TM4-TM5 interface prevents activation by agonist, whereas locking the TM6 interface leads to a constitutively active receptor. These data provide important information on the activation mechanism of mGluRs and improve our understanding of the structural basis of the negative cooperativity observed in these GPCR dimers.
Collapse
MESH Headings
- Alanine/genetics
- Animals
- COS Cells
- Chlorocebus aethiops
- Cysteine/genetics
- HEK293 Cells
- Humans
- Ligands
- Models, Molecular
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Multimerization
- Protein Structure, Tertiary
- Protein Subunits
- Rats
- Receptor, Metabotropic Glutamate 5/agonists
- Receptor, Metabotropic Glutamate 5/chemistry
- Receptor, Metabotropic Glutamate 5/genetics
- Receptors, GABA-B/chemistry
- Receptors, GABA-B/genetics
- Receptors, GABA-B/metabolism
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Transcriptional Activation
- Transfection
Collapse
Affiliation(s)
- Li Xue
- 1] Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. [2] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [3] INSERM, U661, Montpellier, France. [4] Université Montpellier 1 &2, Montpellier, France
| | - Xavier Rovira
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Pauline Scholler
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Han Zhao
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Philippe Rondard
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| |
Collapse
|
21
|
Low dosage of rimonabant leads to anxiolytic-like behavior via inhibiting expression levels and G-protein activity of kappa opioid receptors in a cannabinoid receptor independent manner. Neuropharmacology 2015; 89:298-307. [DOI: 10.1016/j.neuropharm.2014.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/19/2014] [Accepted: 10/04/2014] [Indexed: 12/15/2022]
|
22
|
Wnorowski A, Jozwiak K. Homo- and hetero-oligomerization of β2-adrenergic receptor in receptor trafficking, signaling pathways and receptor pharmacology. Cell Signal 2014; 26:2259-65. [PMID: 25049076 DOI: 10.1016/j.cellsig.2014.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
The β2-adrenergic receptor (β2AR) is the prototypic member of G protein-coupled receptors (GPCRs) involved in the production of physiological responses to adrenaline and noradrenaline. Research done in the past few years vastly demonstrated that β2AR can form homo- and hetero-oligomers. Despite the fact that currently this phenomenon is widely accepted, the spread and relevance of β2AR oligomerization are still a matter of debate. This review considers the progress achieved in the field of β2AR oligomerization with focus on the implications of the receptor-receptor interactions to β2AR trafficking, pharmacology and downstream signal transduction pathways.
Collapse
Affiliation(s)
- Artur Wnorowski
- Laboratory of Medicinal Chemistry and Neuroengineering, Department of Chemistry, Medical University of Lublin, 20-093 Lublin, Poland.
| | - Krzysztof Jozwiak
- Laboratory of Medicinal Chemistry and Neuroengineering, Department of Chemistry, Medical University of Lublin, 20-093 Lublin, Poland.
| |
Collapse
|
23
|
Massotte D. In vivo opioid receptor heteromerization: where do we stand? Br J Pharmacol 2014; 172:420-34. [PMID: 24666391 DOI: 10.1111/bph.12702] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Opioid receptors are highly homologous GPCRs that modulate brain function at all levels of neural integration, including autonomous, sensory, emotional and cognitive processing. Opioid receptors functionally interact in vivo, but the underlying mechanisms involving direct receptor-receptor interactions, affecting signalling pathways or engaging different neuronal circuits, remain unsolved. Heteromer formation through direct physical interaction between two opioid receptors or between an opioid receptor and a non-opioid one has been postulated and can be characterized by specific ligand binding, receptor signalling and trafficking properties. However, despite numerous studies in heterologous systems, evidence for physical proximity in vivo is only available for a limited number of opioid heteromers, and their physiopathological implication remains largely unknown mostly due to the lack of appropriate tools. Nonetheless, data collected so far using endogenous receptors point to a crucial role for opioid heteromers as a molecular entity that could underlie human pathologies such as alcoholism, acute or chronic pain as well as psychiatric disorders. Opioid heteromers therefore stand as new therapeutic targets for the drug discovery field. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
Collapse
Affiliation(s)
- D Massotte
- Institut des Neurosciences Cellulaires et Intégratives, INCI, Strasbourg, France
| |
Collapse
|
24
|
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
|
25
|
Zádor F, Kocsis D, Borsodi A, Benyhe S. Micromolar concentrations of rimonabant directly inhibits delta opioid receptor specific ligand binding and agonist-induced G-protein activity. Neurochem Int 2014; 67:14-22. [PMID: 24508403 DOI: 10.1016/j.neuint.2013.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 11/26/2013] [Accepted: 12/17/2013] [Indexed: 12/16/2022]
Abstract
WHAT IS KNOWN There is a growing number of evidence showing, that the cannabinoid receptor 1 (CB1) antagonist rimonabant has many non-cannabimimetic actions, such as affecting the opioid system. The direct effect of rimonabant on opioid receptors has been studied so far mainly on μ-opioid receptors. However recently the δ-opioid receptor (DOR) receives much more attention as before, due to its potential therapeutic applications, such as nociception or treatment for psychiatric disorders. OBJECTIVES To investigate the direct effect of rimonabant on DOR specific ligand binding and on the DOR mediated G-protein activation. RESULTS Micromolar concentrations of rimonabant directly inhibited the DOR specific agonist binding in radioligand competition binding experiments using Chinese hamster ovary cells stably transfected with mouse DOR (CHO-mDOR). However the inhibition occurred also in the subnanomolar range during DOR specific antagonist binding in similar experimental conditions. In functional [(35)S]GTPγS binding assays rimonabant significantly decreased the basal receptor activity in CHO-mDOR but also in parental CHO cell membranes. During DOR agonist stimulation, micromolar concentration of rimonabant attenuated the DOR G-protein activation and the potency of the activator ligand in [(35)S]GTPγS binding assays performed in CHO-mDOR, in wild type and also in CB1/CB2 double knock-out mouse forebrain membranes. Yet again this inhibitory action was DOR specific, since it did not occur during other specific GPCR agonist mediated G-protein activation. CONCLUSION Rimonabant directly inhibited DOR function in the micromolar concentrations. The inhibitory actions indicate an antagonistic behavior towards DOR which was established by the followings: (i) rimonabant inhibited DOR antagonist binding more effectively than agonist binding, (ii) the inverse agonistic, agonistic effect of the compound can be excluded, and (iii) additionally according to previous findings the allosteric mechanism can also be foreclosed.
Collapse
MESH Headings
- Animals
- CHO Cells
- Cricetinae
- Cricetulus
- GTP-Binding Proteins/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Ligands
- Mice
- Piperidines/pharmacology
- Protein Binding
- Pyrazoles/pharmacology
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB2/genetics
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/metabolism
- Rimonabant
Collapse
Affiliation(s)
- Ferenc Zádor
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Dóra Kocsis
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary
| | - Anna Borsodi
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary
| | - Sándor Benyhe
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary
| |
Collapse
|
26
|
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
|
27
|
Arachiche A, Mumaw MM, de la Fuente M, Nieman MT. Protease-activated receptor 1 (PAR1) and PAR4 heterodimers are required for PAR1-enhanced cleavage of PAR4 by α-thrombin. J Biol Chem 2013; 288:32553-32562. [PMID: 24097976 DOI: 10.1074/jbc.m113.472373] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin is a potent platelet agonist that activates platelets and other cells of the cardiovascular system by cleaving its G-protein-coupled receptors, protease-activated receptor 1 (PAR1), PAR4, or both. We now show that cleaving PAR1 and PAR4 with α-thrombin induces heterodimer formation. PAR1-PAR4 heterodimers were not detected when unstimulated; however, when the cells were stimulated with 10 nm α-thrombin, we were able to detect a strong interaction between PAR1 and PAR4 by bioluminescence resonance energy transfer. In contrast, activating the receptors without cleavage using PAR1 and PAR4 agonist peptides (TFLLRN and AYPGKF, respectively) did not enhance heterodimer formation. Preventing PAR1 or PAR4 cleavage with point mutations or hirugen also prevented the induction of heterodimers. To further characterize the PAR1-PAR4 interactions, we mapped the heterodimer interface by introducing point mutations in transmembrane helix 4 of PAR1 or PAR4 that prevented heterodimer formation. Finally, we show that mutations in PAR1 or PAR4 at the heterodimer interface prevented PAR1-assisted cleavage of PAR4. These data demonstrate that PAR1 and PAR4 require allosteric changes induced via receptor cleavage by α-thrombin to mediate heterodimer formation, and we have determined the PAR1-PAR4 heterodimer interface. Our findings show that PAR1 and PAR4 have dynamic interactions on the cell surface that should be taken into account when developing and characterizing PAR antagonists.
Collapse
Affiliation(s)
- Amal Arachiche
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michele M Mumaw
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - María de la Fuente
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Marvin T Nieman
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106.
| |
Collapse
|
28
|
Schellekens H, Dinan TG, Cryan JF. Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward. Front Neurosci 2013; 7:148. [PMID: 24009547 PMCID: PMC3757321 DOI: 10.3389/fnins.2013.00148] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/01/2013] [Indexed: 12/25/2022] Open
Abstract
The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense "comfort-foods" and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs.
Collapse
|
29
|
|
30
|
Dell'Orco D. A physiological role for the supramolecular organization of rhodopsin and transducin in rod photoreceptors. FEBS Lett 2013; 587:2060-6. [PMID: 23684654 DOI: 10.1016/j.febslet.2013.05.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
Abstract
Vertebrate vision in rod photoreceptors begins when a photon hits the visual pigment rhodopsin (Rh) and triggers the phototransduction cascade. Although the fine biochemical and biophysical details of this paradigmatic signalling pathway have been studied for decades, phototransduction still presents unclear mechanistic aspects. Increasing lines of evidence suggest that the visual pigment rhodopsin (Rh) is natively organized in dimers on the surface of disc membranes, and may form higher order "paracrystalline" assemblies, which are not easy to reconcile with the classical collision-coupling mechanistic scenario evoked to explain the extremely fast molecular processes required in phototransduction. The questioned and criticized existence of paracrystalline Rh rafts can be fully accepted only if it can be explained in functional terms by a solid mechanistic picture. Here we discuss how recent data suggest a physiological role for supramolecular assemblies of Rh and its cognate G protein transducin (Gt), which by forming transient complexes in the dark may ensure rapid activation of the cascade even in a crowded environment that, according to the classical picture, would otherwise stop the cascade.
Collapse
Affiliation(s)
- Daniele Dell'Orco
- Department of Life Sciences and Reproduction, Section of Biological Chemistry, and Centre for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona, Italy.
| |
Collapse
|
31
|
Topiol S. X-ray structural information of GPCRs in drug design: what are the limitations and where do we go? Expert Opin Drug Discov 2013; 8:607-20. [PMID: 23537065 DOI: 10.1517/17460441.2013.783815] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION In 2007, the X-ray structural determination of non-rhodopsin G-Protein coupled receptors (GPCRs), considered the most extensively targeted protein class for marketed drugs, commenced. With the relatively rapid availability of additional structures, an assessment of the progression made is needed in addition to the assessment of the understandings gleaned, deployment successes and forthcoming prospects. AREAS COVERED The author reviews the approaches and tools that have made it possible to determine the three dimensional structures of GPCRs using X-ray crystallography. Furthermore, the author describes the methods suited for crystallization of membrane bound GPCR proteins including the lipidic cubic phase and various protein modification approaches. The author also provides highlights, from the literature, of the structures determined to date including targets solved, the nature of the content provided (such as selectivity, activating vs. inactivating determinants) and how these structural features relate to drug design strategies. EXPERT OPINION The GPCR X-ray structures that have been so far determined have yielded significant information. This has presented dramatic evidence concerning their ability to impact the discovery of compounds through their action as traditional, orthosteric modulators. It is, however, noted that more challenging design strategies, such as identifying biased agonists and the use of sites remote from the orthosteric site for allosteric modulation, are still in their infancy.
Collapse
Affiliation(s)
- Sid Topiol
- 3D-2Drug LLC, PO Box 184, Fair Lawn, NJ 07410, USA.
| |
Collapse
|
32
|
Krause K, Giménez-Arnau A, Martinez-Escala E, Farré-Albadalejo M, Abajian M, Church MK, Maurer M. Platelet-activating factor (PAF) induces wheal and flare skin reactions independent of mast cell degranulation. Allergy 2013; 68:256-8. [PMID: 23320562 DOI: 10.1111/all.12083] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2012] [Indexed: 12/01/2022]
Abstract
BACKGROUND Platelet-activating factor (PAF) causes wheal and flare responses which are abrogated by H1-antihistamines giving rise to the hypothesis that PAF-induced wheal development is secondary to histamine release from dermal mast cells. But is this hypothesis correct? METHODS Wheal and flare responses were induced by intradermal injection of PAF, codeine and histamine in 14 healthy volunteers. Dermal histamine and PGD2 contractions were measured using microdialysis. RESULTS PAF, unlike histamine and codeine, did not cause a statistically significant rise in mean histamine levels with ten persons showing negligible histamine release. Codeine caused a significant but variable histamine release, ranging from 29 to 282 ng/ml. Codeine, but not PAF or histamine, caused a small but statistically significant release of PGD2. CONCLUSION Wheal and flare reactions in human skin induced by PAF are not associated with histamine release and, therefore, appear to be independent of mast cell degranulation.
Collapse
Affiliation(s)
- K. Krause
- Department of Dermatology and Allergy; Allergie-Centrum-Charité; Charité - Universitätsmedizin Berlin; Berlin; Germany
| | - A. Giménez-Arnau
- Department of Dermatology and Pharmacology; Hospital del Mar, Universitat Autònoma de Barcelona; Barcelona; Spain
| | - E. Martinez-Escala
- Department of Dermatology and Pharmacology; Hospital del Mar, Universitat Autònoma de Barcelona; Barcelona; Spain
| | - M. Farré-Albadalejo
- Department of Dermatology and Pharmacology; Hospital del Mar, Universitat Autònoma de Barcelona; Barcelona; Spain
| | - M. Abajian
- Department of Dermatology and Allergy; Allergie-Centrum-Charité; Charité - Universitätsmedizin Berlin; Berlin; Germany
| | - M. K. Church
- Department of Dermatology and Allergy; Allergie-Centrum-Charité; Charité - Universitätsmedizin Berlin; Berlin; Germany
| | - M. Maurer
- Department of Dermatology and Allergy; Allergie-Centrum-Charité; Charité - Universitätsmedizin Berlin; Berlin; Germany
| |
Collapse
|
33
|
Bindslev N. Allosteric transition: a comparison of two models. BMC Pharmacol Toxicol 2013; 14:4. [PMID: 23298758 PMCID: PMC3599370 DOI: 10.1186/2050-6511-14-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 12/10/2012] [Indexed: 11/10/2022] Open
Abstract
Introduction Two recent models are in use for analysis of allosteric drug action at receptor sites remote from orthosteric binding sites. One is an allosteric two-state mechanical model derived in 2000 by David Hall. The other is an extended operational model developed in 2007 by Arthur Christopoulos’s group. The models are valid in pharmacology, enzymology, transportology as well as several other fields of biology involving allosteric concentration effects. Results I show here that Hall’s model for interactions between an orthoster, an alloster, and a receptive unit is the best choice of model both for simulation and analysis of allosteric concentration-responses at equilibrium or steady-state. Conclusions As detailed knowledge of receptors systems becomes available, systems with several pathways and states and/ or more than two binding sites should be analysed by extended forms of the Hall model rather than for instance a Hill type exponentiation of terms as introduced in non-mechanistic (operational) model approaches; yielding semi-quantitative estimates of actual system parameters based on Hill’s unlikely simultaneity model for G protein-coupled receptors.
Collapse
Affiliation(s)
- Niels Bindslev
- Synagics Lab, Endocrinology Section, Department of Biomedical Sciences, The Medical Faculty, Panum Building, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark.
| |
Collapse
|
34
|
Maggio R, Rocchi C, Scarselli M. Experimental strategies for studying G protein-coupled receptor homo- and heteromerization with radioligand binding and signal transduction methods. Methods Enzymol 2013; 521:295-310. [PMID: 23351746 DOI: 10.1016/b978-0-12-391862-8.00016-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Before the molecular biology era, functional experiments on isolated organs and radioligand binding and biochemical experiments on animal tissues were widely used to characterize G protein-coupled receptors (GPCRs). The introduction of recombinant cell lines expressing a single GPCR type has been a big step forward for studying both drug-receptor interactions and signal transduction. Before the introduction of the concept of receptor oligomerization, all data generated were attributed to the interaction of drugs with receptor monomers. Now, considerable data must be reinterpreted in light of receptor homo- and heteromerization. In this chapter, we will review some of the methods used to study radioligand binding and signal transduction modifications induced by GPCR homo- and heteromerization.
Collapse
Affiliation(s)
- Roberto Maggio
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | | | | |
Collapse
|
35
|
Hetero-oligomerization and Specificity Changes of G Protein-Coupled Purinergic Receptors. Methods Enzymol 2013; 521:239-57. [DOI: 10.1016/b978-0-12-391862-8.00013-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
|
36
|
Quaternary Structure Predictions and Structural Communication Features of GPCR Dimers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:105-42. [DOI: 10.1016/b978-0-12-386931-9.00005-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
37
|
Jäntti MH, Putula J, Turunen PM, Näsman J, Reijonen S, Lindqvist C, Kukkonen JP. Autocrine endocannabinoid signaling through CB1 receptors potentiates OX1 orexin receptor signaling. Mol Pharmacol 2012; 83:621-32. [PMID: 23233488 DOI: 10.1124/mol.112.080523] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been proposed that OX(1) orexin receptors and CB(1) cannabinoid receptors can form heteromeric complexes, which affect the trafficking of OX(1) receptors and potentiate OX(1) receptor signaling to extracellular signal-regulated kinase (ERK). We have recently shown that OX(1) receptor activity releases high levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG), suggesting an alternative route for OX(1)-CB(1) receptor interaction in signaling, for instance, in retrograde synaptic transmission. In the current study, we set out to investigate this possibility utilizing recombinant Chinese hamster ovary K1 cells. 2-AG released from OX(1) receptor-expressing cells acted as a potent paracrine messenger stimulating ERK activity in neighboring CB(1) receptor-expressing cells. When OX(1) and CB(1) receptors were expressed in the same cells, OX(1) stimulation-induced ERK phosphorylation and activity were strongly potentiated. The potentiation but not the OX(1) response as such was fully abolished by specific inhibition of CB(1) receptors or the enzyme responsible for 2-AG generation, diacylglycerol lipase (DAGL). Although the results do not exclude the previously proposed OX(1)-CB(1) heteromerization, they nevertheless unequivocally identify DAGL-dependent 2-AG generation as the pivotal determinant of the OX(1)-CB(1) synergism and thus suggest a functional rather than a molecular interaction of OX(1) and CB(1) receptors.
Collapse
Affiliation(s)
- Maria H Jäntti
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | |
Collapse
|
38
|
Kukkonen JP. Physiology of the orexinergic/hypocretinergic system: a revisit in 2012. Am J Physiol Cell Physiol 2012; 304:C2-32. [PMID: 23034387 DOI: 10.1152/ajpcell.00227.2012] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The neuropeptides orexins and their G protein-coupled receptors, OX(1) and OX(2), were discovered in 1998, and since then, their role has been investigated in many functions mediated by the central nervous system, including sleep and wakefulness, appetite/metabolism, stress response, reward/addiction, and analgesia. Orexins also have peripheral actions of less clear physiological significance still. Cellular responses to the orexin receptor activity are highly diverse. The receptors couple to at least three families of heterotrimeric G proteins and other proteins that ultimately regulate entities such as phospholipases and kinases, which impact on neuronal excitation, synaptic plasticity, and cell death. This article is a 10-year update of my previous review on the physiology of the orexinergic/hypocretinergic system. I seek to provide a comprehensive update of orexin physiology that spans from the molecular players in orexin receptor signaling to the systemic responses yet emphasizing the cellular physiological aspects of this system.
Collapse
Affiliation(s)
- Jyrki P Kukkonen
- Dept. of Veterinary Biosciences, University of Helsinki, Finland.
| |
Collapse
|
39
|
Zoenen M, Urizar E, Swillens S, Vassart G, Costagliola S. Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers. Nat Commun 2012; 3:1007. [DOI: 10.1038/ncomms1991] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/06/2012] [Indexed: 11/09/2022] Open
|
40
|
Allosteric modulators of rhodopsin-like G protein-coupled receptors: opportunities in drug development. Pharmacol Ther 2012; 135:292-315. [PMID: 22728155 DOI: 10.1016/j.pharmthera.2012.06.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 11/21/2022]
Abstract
Rhodopsin-like (class A) G protein-coupled receptors (GPCRs) are one of the most important classes of drug targets. The discovery that these GPCRs can be allosterically modulated by small drug molecules has opened up new opportunities in drug development. It will allow the drugability of "difficult targets", such as GPCRs activated by large (glyco)proteins, or by very polar or highly lipophilic physiological agonists. Receptor subtype selectivity should be more easily achievable with allosteric than with orthosteric ligands. Allosteric modulation will allow a broad spectrum of pharmacological effects largely expanding that of orthosteric ligands. Furthermore, allosteric modulators may show an improved safety profile as compared to orthosteric ligands. Only recently, the explicit search for allosteric modulators has been started for only a few rhodopsin-like GPCRs. The first negative allosteric modulators (allosteric antagonists) of chemokine receptors, maraviroc (CCR5 receptor), used in HIV therapy, and plerixafor (CXCR4 receptor) for stem cell mobilization, have been approved as drugs. The development of allosteric modulators for rhodopsin-like GPCRs as novel drugs is still at an early stage; it appears highly promising.
Collapse
|
41
|
Goddard AD, Watts A. Contributions of fluorescence techniques to understanding G protein-coupled receptor dimerisation. Biophys Rev 2012; 4:291-298. [PMID: 28510206 DOI: 10.1007/s12551-012-0073-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/13/2012] [Indexed: 12/27/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest class of eukaryotic cell-surface receptors and, over the last decade, it has become clear that they are capable of dimerisation. Whilst many biochemical and biophysical approaches have been used to study dimerisation, fluorescence techniques, including Förster resonance energy transfer and single molecule fluorescence, have been key players. Here we review recent contributions of fluorescence techniques to investigate GPCR dimers, including dimerisation in cell membranes and native tissues, the effect of ligand binding on dimerisation and the kinetics of dimer formation and dissociation. The challenges of studying multicomponent membrane protein systems have led to the development and refinement of many fluorescence assays, allowing the functional consequences of receptor dimerisation to be investigated and individual protein molecules to be imaged in the membranes of living cells. It is likely that the fluorescence techniques described here will be of use for investigating many other multicomponent membrane protein systems.
Collapse
Affiliation(s)
- Alan D Goddard
- Biomembrane Structure Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Biomembrane Structure Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| |
Collapse
|
42
|
Cottet M, Faklaris O, Maurel D, Scholler P, Doumazane E, Trinquet E, Pin JP, Durroux T. BRET and Time-resolved FRET strategy to study GPCR oligomerization: from cell lines toward native tissues. Front Endocrinol (Lausanne) 2012; 3:92. [PMID: 22837753 PMCID: PMC3401989 DOI: 10.3389/fendo.2012.00092] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [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: 07/03/2012] [Indexed: 11/13/2022] Open
Abstract
The concept of oligomerization of G protein-coupled receptor (GPCR) opens new perspectives regarding physiological function regulation. The capacity of one GPCR to modify its binding and coupling properties by interacting with a second one can be at the origin of regulations unsuspected two decades ago. Although the concept is interesting, its validation at a physiological level is challenging and probably explains why receptor oligomerization is still controversial. Demonstrating direct interactions between two proteins is not trivial since few techniques present a spatial resolution allowing this precision. Resonance energy transfer (RET) strategies are actually the most convenient ones. During the last two decades, bioluminescent resonance energy transfer and time-resolved fluorescence resonance energy transfer (TR-FRET) have been widely used since they exhibit high signal-to-noise ratio. Most of the experiments based on GPCR labeling have been performed in cell lines and it has been shown that all GPCRs have the propensity to form homo- or hetero-oligomers. However, whether these data can be extrapolated to GPCRs expressed in native tissues and explain receptor functioning in real life, remains an open question. Native tissues impose different constraints since GPCR sequences cannot be modified. Recently, a fluorescent ligand-based GPCR labeling strategy combined to a TR-FRET approach has been successfully used to prove the existence of GPCR oligomerization in native tissues. Although the RET-based strategies are generally quite simple to implement, precautions have to be taken before concluding to the absence or the existence of specific interactions between receptors. For example, one should exclude the possibility of collision of receptors diffusing throughout the membrane leading to a specific FRET signal. The advantages and the limits of different approaches will be reviewed and the consequent perspectives discussed.
Collapse
Affiliation(s)
- Martin Cottet
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | - Orestis Faklaris
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | - Damien Maurel
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | - Pauline Scholler
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | - Etienne Doumazane
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | | | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle CNRS, UMR 5203,Montpellier, France
- INSERM, U.661, Montpellier and Université Montpellier 1,2,Montpellier, France
- *Correspondence: Thierry Durroux, Institut de Génomique Fonctionnelle CNRS, UMR 5203, Montpellier, France; INSERM U661, Montpellier and Université Montpellier 1,2, 141 Rue de la Cardonille, 34094 Montpellier Cedex 5, France. e-mail:
| |
Collapse
|
43
|
Abstract
Radioligand binding is widely used to characterize receptors and determine their anatomical distribution, particularly the superfamily of seven transmembrane-spanning G protein-coupled receptors for both established transmitters such as endothelin-1 and an increasing number of orphan receptors recently paired with their cognate ligands. Three types of assay are described. In saturation experiments, tissue sections, cultured cells, or homogenates are incubated with an increasing concentration of a radiolabeled ligand, which can be a labeled analog of a naturally occurring transmitter, hormone, or synthetic drug. Analysis using iterative nonlinear curve-fitting programs, such as KELL, measures the affinity of the labeled ligand for a receptor (equilibrium dissociation constant, K ( D )), receptor density (B (max)), and Hill slope (nH). The affinity and selectivity of an unlabeled ligand to compete for the binding of a fixed concentration of a radiolabeled ligand to a receptor are determined using a competition binding assay. Kinetic assays measure the rate of association to or dissociation from a receptor from which a kinetic K ( D ) may be derived. Quantitative autoradiography and image analysis is a sensitive technique to detect low levels of radiolabeled ligands and determine the anatomical distribution of receptors in sections that retain the morphology of the tissue. The measurement of bound radioligand within discrete regions of autoradiographical images using -computer-assisted image analysis is described.
Collapse
Affiliation(s)
- Janet J Maguire
- Clinical Pharmacology Unit, Addenbrooke's Centre for Clinical Investigation, University of Cambridge, Cambridge, UK.
| | | | | |
Collapse
|
44
|
Koschatzky S, Gmeiner P. Selective agonists for dopamine/neurotensin receptor heterodimers. ChemMedChem 2011; 7:509-14. [PMID: 22213714 DOI: 10.1002/cmdc.201100499] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/05/2011] [Indexed: 12/26/2022]
Abstract
The neuromodulatory peptide neurotensin has been described to functionally interact with dopaminergic pathways of the human brain. We employed radioligand binding studies to investigate the physical interaction between co-expressed dopamine D(2L) or D₃ and neurotensin NTS₁ or NTS₂ receptors. Substantial cross-inhibitory effects of both receptor subtypes NTS(1) and NTS₂ on the agonist binding of D(2L) or D₃ were detected in the presence of neurotensin. To identify ligand-specific modulation and subtype-dependent differences, the novel dopamine receptor agonists 5 and 6 bearing the 7-OH-DPAT pharmacophore were synthesized. Exceptional ligand specificity was observed for D₃-NTS₂ co-expression, which gave a 20-fold decrease in affinity for biphenylcarboxamide 5 in the presence of neurotensin. Comparing the binding properties of dopaminergic compounds in the presence of neurotensin, dopamine receptor subtype-selective profiles of the cross-inhibitory effect of neurotensin were observed.
Collapse
Affiliation(s)
- Susanne Koschatzky
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstr. 19, 91052 Erlangen, Germany
| | | |
Collapse
|
45
|
Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
| | | |
Collapse
|
46
|
Vischer HF, Watts AO, Nijmeijer S, Leurs R. G protein-coupled receptors: walking hand-in-hand, talking hand-in-hand? Br J Pharmacol 2011; 163:246-60. [PMID: 21244374 DOI: 10.1111/j.1476-5381.2011.01229.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Most cells express a panel of different G protein-coupled receptors (GPCRs) allowing them to respond to at least a corresponding variety of extracellular ligands. In order to come to an integrative well-balanced functional response these ligand-receptor pairs can often cross-regulate each other. Although most GPCRs are fully capable to induce intracellular signalling upon agonist binding on their own, many GPCRs, if not all, appear to exist and function in homomeric and/or heteromeric assemblies for at least some time. Such heteromeric organization offers unique allosteric control of receptor pharmacology and function between the protomers and might even unmask 'new' features. However, it is important to realize that some functional consequences that are proposed to originate from heteromeric receptor interactions may also be observed due to intracellular crosstalk between signalling pathways of non-associated GPCRs.
Collapse
Affiliation(s)
- Henry F Vischer
- Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
47
|
Ward RJ, Pediani JD, Milligan G. Heteromultimerization of cannabinoid CB(1) receptor and orexin OX(1) receptor generates a unique complex in which both protomers are regulated by orexin A. J Biol Chem 2011; 286:37414-28. [PMID: 21908614 PMCID: PMC3199489 DOI: 10.1074/jbc.m111.287649] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/09/2011] [Indexed: 11/06/2022] Open
Abstract
Agonist-induced internalization was observed for both inducible and constitutively expressed forms of the cannabinoid CB(1) receptor. These were also internalized by the peptide orexin A, which has no direct affinity for the cannabinoid CB(1) receptor, but only when the orexin OX(1) receptor was co-expressed along with the cannabinoid CB(1) receptor. This effect of orexin A was concentration-dependent and blocked by OX(1) receptor antagonists. Moreover, the ability of orexin A to internalize the CB(1) receptor was also blocked by CB(1) receptor antagonists. Remarkably, orexin A was substantially more potent in producing internalization of the CB(1) receptor than in causing internalization of the bulk OX(1) receptor population, and this was true in cells in which the CB(1) receptor was maintained at a constant level, whereas levels of OX(1) could be varied and vice versa. Both co-immunoprecipitation and cell surface, homogenous time-resolved fluorescence resonance energy transfer based on covalent labeling of N-terminal "SNAP" and "CLIP" tags present in the extracellular N-terminal domain of the receptors confirmed the capacity of these two receptors to heteromultimerize. These studies confirm the capacity of the CB(1) and OX(1) receptors to interact directly and demonstrate that this complex has unique regulatory characteristics. The higher potency of the agonist orexin A to regulate the CB(1)-OX(1) heteromer compared with the OX(1)-OX(1) homomer present in the same cells and the effects of CB(1) receptor antagonists on the function of orexin A suggest an interplay between these two systems that may modulate appetite, feeding, and wakefulness.
Collapse
Affiliation(s)
- Richard J. Ward
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - John D. Pediani
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Graeme Milligan
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| |
Collapse
|
48
|
May LT, Bridge LJ, Stoddart LA, Briddon SJ, Hill SJ. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics. FASEB J 2011; 25:3465-76. [PMID: 21715680 PMCID: PMC3177574 DOI: 10.1096/fj.11-186296] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A growing awareness indicates that many G-protein-coupled receptors (GPCRs) exist as homodimers, but the extent of the cooperativity across the dimer interface has been largely unexplored. Here, measurement of the dissociation kinetics of a fluorescent agonist (ABA-X-BY630) from the human A1 or A3 adenosine receptors expressed in CHO-K1 cells has provided evidence for highly cooperative interactions between protomers of the A3-receptor dimer in single living cells. In the absence of competitive ligands, the dissociation rate constants of ABA-X-BY630 from A1 and A3 receptors were 1.45 ± 0.05 and 0.57 ± 0.07 min−1, respectively. At the A3 receptor, this could be markedly increased by both orthosteric agonists and antagonists [15-, 9-, and 19-fold for xanthine amine congener (XAC), 5′-(N-ethyl carboxamido)adenosine (NECA), and adenosine, respectively] and reduced by coexpression of a nonbinding (N250A) A3-receptor mutant. The changes in ABA-X-BY630 dissociation were much lower at the A1 receptor (1.5-, 1.4-, and 1.5-fold). Analysis of the pEC50 values of XAC, NECA, and adenosine for the ABA-X-BY630-occupied A3-receptor dimer yielded values of 6.0 ± 0.1, 5.9 ± 0.1, and 5.2 ± 0.1, respectively. This study provides new insight into the spatial and temporal specificity of drug action that can be provided by allosteric modulation across a GPCR homodimeric interface.—May, L. T., Bridge, L. J., Stoddart, L. A., Briddon, S. J., Hill, S. J. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics.
Collapse
Affiliation(s)
- Lauren T May
- Institute of Cell Signalling, School of Biomedical Sciences, The University of Nottingham, Nottingham, UK, NG7 2UH
| | | | | | | | | |
Collapse
|
49
|
Koschatzky S, Tschammer N, Gmeiner P. Cross-receptor interactions between dopamine D2L and neurotensin NTS1 receptors modulate binding affinities of dopaminergics. ACS Chem Neurosci 2011; 2:308-16. [PMID: 22778874 DOI: 10.1021/cn200020y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/11/2011] [Indexed: 11/30/2022] Open
Abstract
Dopaminergic systems have been described to functionally interact with the neuromodulatory peptide neurotensin. Employing fluorescence detected coimmunoprecipitation and radioligand binding experiments, we herein demonstrate that coexpression of dopamine D(2L) receptor and the neurotensin receptor subtype NTS(1) leads to physical interaction and the formation of heteromers in transfected human embryonic kidney 293 cells. In this in vitro system, a trans-inhibitory effect on the agonist binding affinity of D(2) was observed in presence of neurotensin. To correlate between the functional properties of dopaminergic agents and the magnitude of neurotensin-induced modulation of D(2L) binding affinities in cells coexpressing D(2L) and NTS(1), a structurally diverse set of dopamine receptor agonists, partial agonists, and antagonists was tested. Ligand specific profiles indicating substantial bias between ligand efficacy and transmodulation were discovered, suggesting a heteromerization-based functional selectivity. In the presence of neurotensin, the novel D(2) agonist FAUC 326 displayed a 34-fold decrease of binding affinity in cells coexpressing D(2L) and NTS(1).
Collapse
Affiliation(s)
- Susanne Koschatzky
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
| | - Nuska Tschammer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
| |
Collapse
|
50
|
González-Maeso J. GPCR oligomers in pharmacology and signaling. Mol Brain 2011; 4:20. [PMID: 21619615 PMCID: PMC3128055 DOI: 10.1186/1756-6606-4-20] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 05/27/2011] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent one of the largest families of cell surface receptors, and are the target of more than half of the current therapeutic drugs on the market. When activated by an agonist, the GPCR undergoes conformational changes that facilitate its interaction with heterotrimeric G proteins, which then relay signals to downstream intracellular effectors. Although GPCRs were thought to function as monomers, many studies support the hypothesis that G protein coupling involves the formation of GPCR homo- and/or hetero-complexes. These complex systems have been suggested to exhibit specific signaling cascades, pharmacological, internalization, and recycling properties. In this review, we summarize recent advances in our understanding of the structure, function and dynamics of GPCR complexes, as well as the findings obtained in animal models.
Collapse
Affiliation(s)
- Javier González-Maeso
- Departments of Psychiatry and Neurology, Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, USA.
| |
Collapse
|