1
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Zhou X, Septien-Gonzalez H, Husaini S, Ward RJ, Milligan G, Gradinaru CC. Diffusion and Oligomerization States of the Muscarinic M 1 Receptor in Live Cells─The Impact of Ligands and Membrane Disruptors. J Phys Chem B 2024; 128:4354-4366. [PMID: 38683784 PMCID: PMC11090110 DOI: 10.1021/acs.jpcb.4c01035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 05/02/2024]
Abstract
G protein-coupled receptors (GPCRs) are a major gateway to cellular signaling, which respond to ligands binding at extracellular sites through allosteric conformational changes that modulate their interactions with G proteins and arrestins at intracellular sites. High-resolution structures in different ligand states, together with spectroscopic studies and molecular dynamics simulations, have revealed a rich conformational landscape of GPCRs. However, their supramolecular structure and spatiotemporal distribution is also thought to play a significant role in receptor activation and signaling bias within the native cell membrane environment. Here, we applied single-molecule fluorescence techniques, including single-particle tracking, single-molecule photobleaching, and fluorescence correlation spectroscopy, to characterize the diffusion and oligomerization behavior of the muscarinic M1 receptor (M1R) in live cells. Control samples included the monomeric protein CD86 and fixed cells, and experiments performed in the presence of different orthosteric M1R ligands and of several compounds known to change the fluidity and organization of the lipid bilayer. M1 receptors exhibit Brownian diffusion characterized by three diffusion constants: confined/immobile (∼0.01 μm2/s), slow (∼0.04 μm2/s), and fast (∼0.14 μm2/s), whose populations were found to be modulated by both orthosteric ligands and membrane disruptors. The lipid raft disruptor C6 ceramide led to significant changes for CD86, while the diffusion of M1R remained unchanged, indicating that M1 receptors do not partition in lipid rafts. The extent of receptor oligomerization was found to be promoted by increasing the level of expression and the binding of orthosteric ligands; in particular, the agonist carbachol elicited a large increase in the fraction of M1R oligomers. This study provides new insights into the balance between conformational and environmental factors that define the movement and oligomerization states of GPCRs in live cells under close-to-native conditions.
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Affiliation(s)
- Xiaohan Zhou
- Department
of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department
of Chemical & Physical Sciences, University
of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Horacio Septien-Gonzalez
- Department
of Chemical & Physical Sciences, University
of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Sami Husaini
- Department
of Chemical & Physical Sciences, University
of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Richard J. Ward
- Centre
for Translational Pharmacology, School of Molecular Biosciences, College
of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K.
| | - Graeme Milligan
- Centre
for Translational Pharmacology, School of Molecular Biosciences, College
of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K.
| | - Claudiu C. Gradinaru
- Department
of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department
of Chemical & Physical Sciences, University
of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
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2
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Mirchandani-Duque M, Choucri M, Hernández-Mondragón JC, Crespo-Ramírez M, Pérez-Olives C, Ferraro L, Franco R, Pérez de la Mora M, Fuxe K, Borroto-Escuela DO. Membrane Heteroreceptor Complexes as Second-Order Protein Modulators: A Novel Integrative Mechanism through Allosteric Receptor-Receptor Interactions. MEMBRANES 2024; 14:96. [PMID: 38786931 PMCID: PMC11122807 DOI: 10.3390/membranes14050096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 04/13/2024] [Accepted: 04/19/2024] [Indexed: 05/25/2024]
Abstract
Bioluminescence and fluorescence resonance energy transfer (BRET and FRET) together with the proximity ligation method revealed the existence of G-protein-coupled receptors, Ionotropic and Receptor tyrosine kinase heterocomplexes, e.g., A2AR-D2R, GABAA-D5R, and FGFR1-5-HT1AR heterocomplexes. Molecular integration takes place through allosteric receptor-receptor interactions in heteroreceptor complexes of synaptic and extra-synaptic regions. It involves the modulation of receptor protomer recognition, signaling and trafficking, as well as the modulation of behavioral responses. Allosteric receptor-receptor interactions in hetero-complexes give rise to concepts like meta-modulation and protein modulation. The introduction of receptor-receptor interactions was the origin of the concept of meta-modulation provided by Katz and Edwards in 1999, which stood for the fine-tuning or modulation of nerve cell transmission. In 2000-2010, Ribeiro and Sebastiao, based on a series of papers, provided strong support for their view that adenosine can meta-modulate (fine-tune) synaptic transmission through adenosine receptors. However, another term should also be considered: protein modulation, which is the key feature of allosteric receptor-receptor interactions leading to learning and consolidation by novel adapter proteins to memory. Finally, it must be underlined that allosteric receptor-receptor interactions and their involvement both in brain disease and its treatment are of high interest. Their pathophysiological relevance has been obtained, especially for major depressive disorder, cocaine use disorder, and Parkinson's disease.
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Affiliation(s)
- Marina Mirchandani-Duque
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, 29010 Málaga, Spain;
| | - Malak Choucri
- Department of Neuroscience, Karolinska Institutet, Biomedicum (B0852), Solnavägen 9, 17165 Solna, Sweden;
| | - Juan C. Hernández-Mondragón
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (J.C.H.-M.); (M.C.-R.); (M.P.d.l.M.)
| | - Minerva Crespo-Ramírez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (J.C.H.-M.); (M.C.-R.); (M.P.d.l.M.)
| | - Catalina Pérez-Olives
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Universitat de Barcelona, 08007 Barcelona, Spain;
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products University of Ferrara, 44121 Ferrara, Italy; (L.F.); (R.F.)
| | - Rafael Franco
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products University of Ferrara, 44121 Ferrara, Italy; (L.F.); (R.F.)
| | - Miguel Pérez de la Mora
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (J.C.H.-M.); (M.C.-R.); (M.P.d.l.M.)
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Biomedicum (B0852), Solnavägen 9, 17165 Solna, Sweden;
| | - Dasiel O. Borroto-Escuela
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, 29010 Málaga, Spain;
- Department of Neuroscience, Karolinska Institutet, Biomedicum (B0852), Solnavägen 9, 17165 Solna, Sweden;
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3
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Geiser A, Foylan S, Tinning PW, Bryant NJ, Gould GW. GLUT4 dispersal at the plasma membrane of adipocytes: a super-resolved journey. Biosci Rep 2023; 43:BSR20230946. [PMID: 37791639 PMCID: PMC10600063 DOI: 10.1042/bsr20230946] [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: 09/07/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/05/2023] Open
Abstract
In adipose tissue, insulin stimulates glucose uptake by mediating the translocation of GLUT4 from intracellular vesicles to the plasma membrane. In 2010, insulin was revealed to also have a fundamental impact on the spatial distribution of GLUT4 within the plasma membrane, with the existence of two GLUT4 populations at the plasma membrane being defined: (1) as stationary clusters and (2) as diffusible monomers. In this model, in the absence of insulin, plasma membrane-fused GLUT4 are found to behave as clusters. These clusters are thought to arise from exocytic events that retain GLUT4 at their fusion sites; this has been proposed to function as an intermediate hub between GLUT4 exocytosis and re-internalisation. By contrast, insulin stimulation induces the dispersal of GLUT4 clusters into monomers and favours a distinct type of GLUT4-vesicle fusion event, known as fusion-with-release exocytosis. Here, we review how super-resolution microscopy approaches have allowed investigation of the characteristics of plasma membrane-fused GLUT4 and further discuss regulatory step(s) involved in the GLUT4 dispersal machinery, introducing the scaffold protein EFR3 which facilitates localisation of phosphatidylinositol 4-kinase type IIIα (PI4KIIIα) to the cell surface. We consider how dispersal may be linked to the control of transporter activity, consider whether macro-organisation may be a widely used phenomenon to control proteins within the plasma membrane, and speculate on the origin of different forms of GLUT4-vesicle exocytosis.
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Affiliation(s)
- Angéline Geiser
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Shannan Foylan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Peter W Tinning
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - Nia J Bryant
- Department of Biology, University of York, Heslington, York, U.K
| | - Gwyn W Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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4
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The M 1 muscarinic receptor is present in situ as a ligand-regulated mixture of monomers and oligomeric complexes. Proc Natl Acad Sci U S A 2022; 119:e2201103119. [PMID: 35671422 PMCID: PMC9214538 DOI: 10.1073/pnas.2201103119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although it is appreciated that members of the large family of rhodopsin-like cell surface receptors can form dimeric or larger protein complexes when expressed at high levels in cultured cells, their organizational state within native cells and tissues of the body is largely unknown. We assessed this in neurons of the central nervous system by replacing the M1 muscarinic acetylcholine receptor in mice with a form of this receptor with an added fluorescent protein. Receptor function was unaltered by this change, and the biophysical approach we used demonstrated that the receptor exists as a mixture of monomers and dimers or oligomers. Drug treatments that target this receptor promote its monomerization, which may have significance for receptor function. The quaternary organization of rhodopsin-like G protein-coupled receptors in native tissues is unknown. To address this we generated mice in which the M1 muscarinic acetylcholine receptor was replaced with a C-terminally monomeric enhanced green fluorescent protein (mEGFP)–linked variant. Fluorescence imaging of brain slices demonstrated appropriate regional distribution, and using both anti-M1 and anti–green fluorescent protein antisera the expressed transgene was detected in both cortex and hippocampus only as the full-length polypeptide. M1-mEGFP was expressed at levels equal to the M1 receptor in wild-type mice and was expressed throughout cell bodies and projections in cultured neurons from these animals. Signaling and behavioral studies demonstrated M1-mEGFP was fully active. Application of fluorescence intensity fluctuation spectrometry to regions of interest within M1-mEGFP–expressing neurons quantified local levels of expression and showed the receptor was present as a mixture of monomers, dimers, and higher-order oligomeric complexes. Treatment with both an agonist and an antagonist ligand promoted monomerization of the M1-mEGFP receptor. The quaternary organization of a class A G protein-coupled receptor in situ was directly quantified in neurons in this study, which answers the much-debated question of the extent and potential ligand-induced regulation of basal quaternary organization of such a receptor in native tissue when present at endogenous expression levels.
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5
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Dobrovolskaite A, Madan M, Pandey V, Altomare DA, Phanstiel O. The discovery of indolone GW5074 during a comprehensive search for non-polyamine-based polyamine transport inhibitors. Int J Biochem Cell Biol 2021; 138:106038. [PMID: 34252566 DOI: 10.1016/j.biocel.2021.106038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/28/2021] [Accepted: 07/05/2021] [Indexed: 01/15/2023]
Abstract
The native polyamines putrescine, spermidine, and spermine are essential for cell development and proliferation. Polyamine levels are often increased in cancer tissues and polyamine depletion is a validated anticancer strategy. Cancer cell growth can be inhibited by the polyamine biosynthesis inhibitor difluoromethylornithine (DFMO), which inhibits ornithine decarboxylase (ODC), the rate-limiting enzyme in the polyamine biosynthesis pathway. Unfortunately, cells treated with DFMO often replenish their polyamine pools by importing polyamines from their environment. Several polyamine-based molecules have been developed to work as polyamine transport inhibitors (PTIs) and have been successfully used in combination with DFMO in several cancer models. Here, we present the first comprehensive search for potential non-polyamine based PTIs that work in human pancreatic cancer cells in vitro. After identifying and testing five different categories of compounds, we have identified the c-RAF inhibitor, GW5074, as a novel non-polyamine based PTI. GW5074 inhibited the uptake of all three native polyamines and a fluorescent-polyamine probe into human pancreatic cancer cells. GW5074 significantly reduced pancreatic cancer cell growth in vitro when treated in combination with DFMO and a rescuing dose of spermidine. Moreover, GW5074 alone reduced tumor growth when tested in a murine pancreatic cancer mouse model in vivo. In summary, GW5074 is a novel non-polyamine-based PTI that potentiates the anticancer activity of DFMO in pancreatic cancers.
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Affiliation(s)
- Aiste Dobrovolskaite
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, 32827, United States
| | - Meenu Madan
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, 32827, United States
| | - Veethika Pandey
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, 32827, United States
| | - Deborah A Altomare
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, 32827, United States
| | - Otto Phanstiel
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, 32827, United States.
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6
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Işbilir A, Serfling R, Möller J, Thomas R, De Faveri C, Zabel U, Scarselli M, Beck-Sickinger AG, Bock A, Coin I, Lohse MJ, Annibale P. Determination of G-protein-coupled receptor oligomerization by molecular brightness analyses in single cells. Nat Protoc 2021; 16:1419-1451. [PMID: 33514946 DOI: 10.1038/s41596-020-00458-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/03/2020] [Indexed: 02/08/2023]
Abstract
Oligomerization of membrane proteins has received intense research interest because of their importance in cellular signaling and the large pharmacological and clinical potential this offers. Fluorescence imaging methods are emerging as a valid tool to quantify membrane protein oligomerization at high spatial and temporal resolution. Here, we provide a detailed protocol for an image-based method to determine the number and oligomerization state of fluorescently labeled prototypical G-protein-coupled receptors (GPCRs) on the basis of small out-of-equilibrium fluctuations in fluorescence (i.e., molecular brightness) in single cells. The protocol provides a step-by-step procedure that includes instructions for (i) a flexible labeling strategy for the protein of interest (using fluorescent proteins, small self-labeling tags or bio-orthogonal labeling) and the appropriate controls, (ii) performing temporal and spatial brightness image acquisition on a confocal microscope and (iii) analyzing and interpreting the data, excluding clusters and intensity hot-spots commonly observed in receptor distributions. Although specifically tailored for GPCRs, this protocol can be applied to diverse classes of membrane proteins of interest. The complete protocol can be implemented in 1 month.
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Affiliation(s)
- Ali Işbilir
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Robert Serfling
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Jan Möller
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Romy Thomas
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Chiara De Faveri
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Ulrike Zabel
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Marco Scarselli
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - Andreas Bock
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Irene Coin
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Martin J Lohse
- Max Delbrück Center for Molecular Medicine, Berlin, Germany. .,Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany. .,ISAR Bioscience Institute, Munich, Germany.
| | - Paolo Annibale
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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7
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Magalhães DDA, Batista JA, Sousa SG, Ferreira JDS, da Rocha Rodrigues L, Pereira CMC, do Nascimento Lima JV, de Albuquerque IF, Bezerra NLSD, Monteiro CEDS, Franco AX, da Costa Filho HB, Ferreira FCS, Havt A, Di Lenardo D, Vasconcelos DFP, de Oliveira JS, Soares PMG, Barbosa ALDR. McN-A-343, a muscarinic agonist, reduces inflammation and oxidative stress in an experimental model of ulcerative colitis. Life Sci 2021; 272:119194. [PMID: 33609541 DOI: 10.1016/j.lfs.2021.119194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/24/2021] [Accepted: 02/01/2021] [Indexed: 11/30/2022]
Abstract
AIM The aim of the present study was to investigate the anti-inflammatory response mediated of the M1 muscarinic acetylcholine receptor (mAChR) during experimental colitis. MATERIAL AND METHODS After the induction of 6% acetic acid colitis, mice were treated with McN-A-343 0.5, 1.0, and 1.5 mg/kg or dexamethasone (DEXA, 2.0 mg/kg) or pirenzepine (PIR, 10 mg/kg; M1 mAChR antagonist). Colonic inflammation was assessed by macroscopic and microscopic lesion scores, colonic wet weight, myeloperoxidase (MPO) activity, interleukin-1 beta (IL1-β) levels and tumor necrosis factor alpha (TNF-α), glutathione (GSH), malondialdehyde (MDA) and nitrate and nitrite (NO3/NO2), mRNA expression of IKKα, nuclear factor kappa beta (NF-kB) and cyclooxygenase-2 (COX-2), as well protein expression of NF-kB and COX-2. RESULTS Treatment with McN-A-343 at a concentration of 1.5 mg/kg showed a significant reduction in intestinal damage as well as a decrease in wet weight, MPO activity, pro-inflammatory cytokine concentration, markers of oxidative stress and expression of inflammatory mediators. The action of the M1 agonist by the administration of pirenzepine, which promoted the blocking of the mAChR M1-mediated anti-inflammatory response, has also been proven. CONCLUSION The results suggest that peripheral colonic M1 mAChR is involved in reversing the pro-inflammatory effect of experimentally induced colitis, which may represent a promising therapeutic alternative for patients with ulcerative colitis.
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Affiliation(s)
- Diva de Aguiar Magalhães
- Laboratory of Experimental Physiopharmacology, LAFFEX, Federal University of Piauí, Parnaíba, Brazil; The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil
| | - Jalles Arruda Batista
- Laboratory of Experimental Physiopharmacology, LAFFEX, Federal University of Piauí, Parnaíba, Brazil; The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil
| | - Stefany Guimarães Sousa
- Laboratory of Experimental Physiopharmacology, LAFFEX, Federal University of Piauí, Parnaíba, Brazil; The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil
| | - Jayro Dos Santos Ferreira
- Laboratory of Experimental Physiopharmacology, LAFFEX, Federal University of Piauí, Parnaíba, Brazil
| | | | | | | | | | | | | | - Alvaro Xavier Franco
- Laboratory of Physiopharmacology Study of Gastrointestinal Tract, LEFFAG, Federal University of Ceará, Fortaleza, Brazil
| | | | | | - Alexandre Havt
- Laboratory of Molecular Toxinology, LTM, Federal University of Ceará, Fortaleza, CE, Brazil
| | - David Di Lenardo
- Laboratory of Analysis and Histological Processing, LAPHIS, Department of Biomedicine, Federal University of Piauí, Parnaíba, Brazil
| | - Daniel Fernando Pereira Vasconcelos
- The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil; Laboratory of Analysis and Histological Processing, LAPHIS, Department of Biomedicine, Federal University of Piauí, Parnaíba, Brazil
| | - Jefferson Soares de Oliveira
- The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil; Biochemistry Laboratory of Laticifers Plants (LABPL), Department of Biomedicine, Federal University of Piauí, Parnaíba, Brazil
| | - Pedro Marcos Gomes Soares
- Laboratory of Physiopharmacology Study of Gastrointestinal Tract, LEFFAG, Federal University of Ceará, Fortaleza, Brazil
| | - André Luiz Dos Reis Barbosa
- Laboratory of Experimental Physiopharmacology, LAFFEX, Federal University of Piauí, Parnaíba, Brazil; The Northeast Biotechnology Network, Federal University of Piauí, Teresina, Brazil.
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8
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Ward RJ, Pediani JD, Marsango S, Jolly R, Stoneman MR, Biener G, Handel TM, Raicu V, Milligan G. Chemokine receptor CXCR4 oligomerization is disrupted selectively by the antagonist ligand IT1t. J Biol Chem 2021; 296:100139. [PMID: 33268380 PMCID: PMC7949023 DOI: 10.1074/jbc.ra120.016612] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 12/15/2022] Open
Abstract
CXCR4, a member of the family of chemokine-activated G protein-coupled receptors, is widely expressed in immune response cells. It is involved in both cancer development and progression as well as viral infection, notably by HIV-1. A variety of methods, including structural information, have suggested that the receptor may exist as a dimer or an oligomer. However, the mechanistic details surrounding receptor oligomerization and its potential dynamic regulation remain unclear. Using both biochemical and biophysical means, we confirm that CXCR4 can exist as a mixture of monomers, dimers, and higher-order oligomers in cell membranes and show that oligomeric structure becomes more complex as receptor expression levels increase. Mutations of CXCR4 residues located at a putative dimerization interface result in monomerization of the receptor. Additionally, binding of the CXCR4 antagonist IT1t-a small drug-like isothiourea derivative-rapidly destabilizes the oligomeric structure, whereas AMD3100, another well-characterized CXCR4 antagonist, does not. Although a mutation that regulates constitutive activity of CXCR4 also results in monomerization of the receptor, binding of IT1t to this variant promotes receptor dimerization. These results provide novel insights into the basal organization of CXCR4 and how antagonist ligands of different chemotypes differentially regulate its oligomerization state.
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Affiliation(s)
- Richard J Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - John D Pediani
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Sara Marsango
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Richard Jolly
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Michael R Stoneman
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Gabriel Biener
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Valerică Raicu
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Graeme Milligan
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom.
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9
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Toneatti R, Shin JM, Shah UH, Mayer CR, Saunders JM, Fribourg M, Arsenovic PT, Janssen WG, Sealfon SC, López-Giménez JF, Benson DL, Conway DE, González-Maeso J. Interclass GPCR heteromerization affects localization and trafficking. Sci Signal 2020; 13:eaaw3122. [PMID: 33082287 PMCID: PMC7717648 DOI: 10.1126/scisignal.aaw3122] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Membrane trafficking processes regulate G protein-coupled receptor (GPCR) activity. Although class A GPCRs are capable of activating G proteins in a monomeric form, they can also potentially assemble into functional GPCR heteromers. Here, we showed that the class A serotonin 5-HT2A receptors (5-HT2ARs) affected the localization and trafficking of class C metabotropic glutamate receptor 2 (mGluR2) through a mechanism that required their assembly as heteromers in mammalian cells. In the absence of agonists, 5-HT2AR was primarily localized within intracellular compartments, and coexpression of 5-HT2AR with mGluR2 increased the intracellular distribution of the otherwise plasma membrane-localized mGluR2. Agonists for either 5-HT2AR or mGluR2 differentially affected trafficking through Rab5-positive endosomes in cells expressing each component of the 5-HT2AR-mGluR2 heterocomplex alone, or together. In addition, overnight pharmacological 5-HT2AR blockade with clozapine, but not with M100907, decreased mGluR2 density through a mechanism that involved heteromerization between 5-HT2AR and mGluR2. Using TAT-tagged peptides and chimeric constructs that are unable to form the interclass 5-HT2AR-mGluR2 complex, we demonstrated that heteromerization was necessary for the 5-HT2AR-dependent effects on mGluR2 subcellular distribution. The expression of 5-HT2AR also augmented intracellular localization of mGluR2 in mouse frontal cortex pyramidal neurons. Together, our data suggest that GPCR heteromerization may itself represent a mechanism of receptor trafficking and sorting.
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MESH Headings
- Amino Acids/pharmacology
- Animals
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cell Membrane/metabolism
- Clozapine/pharmacology
- Endosomes/metabolism
- HEK293 Cells
- Humans
- Mice, 129 Strain
- Mice, Knockout
- Microscopy, Confocal
- Multiprotein Complexes/chemistry
- Multiprotein Complexes/metabolism
- Protein Multimerization
- Protein Transport/drug effects
- Receptor, Serotonin, 5-HT2A/chemistry
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Receptors, Metabotropic Glutamate/metabolism
- Serotonin Antagonists/pharmacology
- Signal Transduction
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Affiliation(s)
- Rudy Toneatti
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jong M Shin
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Urjita H Shah
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Carl R Mayer
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - Justin M Saunders
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Miguel Fribourg
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Paul T Arsenovic
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - William G Janssen
- Department Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Stuart C Sealfon
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Juan F López-Giménez
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Instituto de Parasitología y Biomedicina "López-Neyra", CSIC, E-18016 Granada, Spain
| | - Deanna L Benson
- Department Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daniel E Conway
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA.
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10
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Petazzi RA, Aji AK, Chiantia S. Fluorescence microscopy methods for the study of protein oligomerization. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 169:1-41. [DOI: 10.1016/bs.pmbts.2019.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Serfling R, Seidel L, Bock A, Lohse MJ, Annibale P, Coin I. Quantitative Single-Residue Bioorthogonal Labeling of G Protein-Coupled Receptors in Live Cells. ACS Chem Biol 2019; 14:1141-1149. [PMID: 31074969 DOI: 10.1021/acschembio.8b01115] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
High-end microscopy studies of G protein-coupled receptors (GPCRs) require installing onto the receptors bright and photostable dyes. Labeling must occur in quantitative yields, to allow stoichiometric data analysis, and in a minimally invasive fashion, to avoid perturbing GPCR function. We demonstrate here that the genetic incorporation of trans-cyclooct-2-ene lysine (TCO*) allows achieving quantitative single-residue labeling of the extracellular loops of the β2-adrenergic and the muscarinic M2 class A GPCRs, as well as of the corticotropin releasing factor class B GPCR. Labeling occurs within a few minutes by reaction with dye-tetrazine conjugates on the surface of live cells and preserves the functionality of the receptors. To precisely quantify the labeling yields, we devise a method based on fluorescence fluctuation microscopy that extracts the number of labeling sites at the single-cell level. Further, we show that single-residue labeling is better suited for studies of GPCR diffusion than fluorescent-protein tags, since the latter can affect the mobility of the receptor. Finally, by performing dual-color competitive labeling on a single TCO* site, we devise a method to estimate the oligomerization state of a GPCR without the need for a biological monomeric reference, which facilitates the application of fluorescence methods to oligomerization studies. As TCO* and the dye-tetrazines used in this study are commercially available and the described microscopy techniques can be performed on a commercial microscope, we expect our approach to be widely applicable to fluorescence microscopy studies of membrane proteins in general.
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Affiliation(s)
- Robert Serfling
- University of Leipzig, Faculty of Life Sciences, Institute of Biochemistry, Brüderstr. 34, 04103 Leipzig, Germany
| | - Lisa Seidel
- University of Leipzig, Faculty of Life Sciences, Institute of Biochemistry, Brüderstr. 34, 04103 Leipzig, Germany
| | - Andreas Bock
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Martin J. Lohse
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Paolo Annibale
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Irene Coin
- University of Leipzig, Faculty of Life Sciences, Institute of Biochemistry, Brüderstr. 34, 04103 Leipzig, Germany
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Luminescence- and Fluorescence-Based Complementation Assays to Screen for GPCR Oligomerization: Current State of the Art. Int J Mol Sci 2019; 20:ijms20122958. [PMID: 31213021 PMCID: PMC6627893 DOI: 10.3390/ijms20122958] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/05/2019] [Accepted: 06/12/2019] [Indexed: 01/22/2023] Open
Abstract
G protein-coupled receptors (GPCRs) have the propensity to form homo- and heterodimers. Dysfunction of these dimers has been associated with multiple diseases, e.g., pre-eclampsia, schizophrenia, and depression, among others. Over the past two decades, considerable efforts have been made towards the development of screening assays for studying these GPCR dimer complexes in living cells. As a first step, a robust in vitro assay in an overexpression system is essential to identify and characterize specific GPCR–GPCR interactions, followed by methodologies to demonstrate association at endogenous levels and eventually in vivo. This review focuses on protein complementation assays (PCAs) which have been utilized to study GPCR oligomerization. These approaches are typically fluorescence- and luminescence-based, making identification and localization of protein–protein interactions feasible. The GPCRs of interest are fused to complementary fluorescent or luminescent fragments that, upon GPCR di- or oligomerization, may reconstitute to a functional reporter, of which the activity can be measured. Various protein complementation assays have the disadvantage that the interaction between the reconstituted split fragments is irreversible, which can lead to false positive read-outs. Reversible systems offer several advantages, as they do not only allow to follow the kinetics of GPCR–GPCR interactions, but also allow evaluation of receptor complex modulation by ligands (either agonists or antagonists). Protein complementation assays may be used for high throughput screenings as well, which is highly relevant given the growing interest and effort to identify small molecule drugs that could potentially target disease-relevant dimers. In addition to providing an overview on how PCAs have allowed to gain better insights into GPCR–GPCR interactions, this review also aims at providing practical guidance on how to perform PCA-based assays.
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13
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Menegatti R, Carvalho FS, Lião LM, Villavicencio B, Verli H, Mourão AA, Xavier CH, Castro CH, Pedrino GR, Franco OL, Oliveira-Silva I, Ashpole NM, Silva ON, Costa EA, Fajemiroye JO. Novel choline analog 2-(4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazin-1-yl)ethan-1-ol produces sympathoinhibition, hypotension, and antihypertensive effects. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1071-1083. [DOI: 10.1007/s00210-019-01649-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/29/2019] [Indexed: 12/14/2022]
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14
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Hailwood JM, Heath CJ, Phillips BU, Robbins TW, Saksida LM, Bussey TJ. Blockade of muscarinic acetylcholine receptors facilitates motivated behaviour and rescues a model of antipsychotic-induced amotivation. Neuropsychopharmacology 2019; 44:1068-1075. [PMID: 30478410 PMCID: PMC6397643 DOI: 10.1038/s41386-018-0281-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/02/2018] [Accepted: 11/17/2018] [Indexed: 02/07/2023]
Abstract
Disruptions to motivated behaviour are a highly prevalent and severe symptom in a number of neuropsychiatric and neurodegenerative disorders. Current treatment options for these disorders have little or no effect upon motivational impairments. We assessed the contribution of muscarinic acetylcholine receptors to motivated behaviour in mice, as a novel pharmacological target for motivational impairments. Touchscreen progressive ratio (PR) performance was facilitated by the nonselective muscarinic receptor antagonist scopolamine as well as the more subtype-selective antagonists biperiden (M1) and tropicamide (M4). However, scopolamine and tropicamide also produced increases in non-specific activity levels, whereas biperiden did not. A series of control tests suggests the effects of the mAChR antagonists were sensitive to changes in reward value and not driven by changes in satiety, motor fatigue, appetite or perseveration. Subsequently, a sub-effective dose of biperiden was able to facilitate the effects of amphetamine upon PR performance, suggesting an ability to enhance dopaminergic function. Both biperiden and scopolamine were also able to reverse a haloperidol-induced deficit in PR performance, however only biperiden was able to rescue the deficit in effort-related choice (ERC) performance. Taken together, these data suggest that the M1 mAChR may be a novel target for the pharmacological enhancement of effort exertion and consequent rescue of motivational impairments. Conversely, M4 receptors may inadvertently modulate effort exertion through regulation of general locomotor activity levels.
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Affiliation(s)
- Jonathan M. Hailwood
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Christopher J. Heath
- 0000000096069301grid.10837.3dSchool of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK
| | - Benjamin U. Phillips
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Trevor W. Robbins
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Lisa M. Saksida
- 0000 0004 1936 8884grid.39381.30Molecular Medicine Research Group, Robarts Research Institute & Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON Canada ,0000 0004 1936 8884grid.39381.30The Brain and Mind Institute, Western University, London, ON Canada
| | - Timothy J. Bussey
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK ,0000 0004 1936 8884grid.39381.30Molecular Medicine Research Group, Robarts Research Institute & Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON Canada ,0000 0004 1936 8884grid.39381.30The Brain and Mind Institute, Western University, London, ON Canada
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15
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Moreno E, Cavic M, Krivokuca A, Casadó V, Canela E. The Endocannabinoid System as a Target in Cancer Diseases: Are We There Yet? Front Pharmacol 2019; 10:339. [PMID: 31024307 PMCID: PMC6459931 DOI: 10.3389/fphar.2019.00339] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/19/2019] [Indexed: 12/15/2022] Open
Abstract
The endocannabinoid system (ECS) has been placed in the anti-cancer spotlight in the last decade. The immense data load published on its dual role in both tumorigenesis and inhibition of tumor growth and metastatic spread has transformed the cannabinoid receptors CB1 (CB1R) and CB2 (CB2R), and other members of the endocannabinoid-like system, into attractive new targets for the treatment of various cancer subtypes. Although the clinical use of cannabinoids has been extensively documented in the palliative setting, clinical trials on their application as anti-cancer drugs are still ongoing. As drug repurposing is significantly faster and more economical than de novo introduction of a new drug into the clinic, there is hope that the existing pharmacokinetic and safety data on the ECS ligands will contribute to their successful translation into oncological healthcare. CB1R and CB2R are members of a large family of membrane proteins called G protein-coupled receptors (GPCR). GPCRs can form homodimers, heterodimers and higher order oligomers with other GPCRs or non-GPCRs. Currently, several CB1R and CB2R-containing heteromers have been reported and, in cancer cells, CB2R form heteromers with the G protein-coupled chemokine receptor CXCR4, the G protein-coupled receptor 55 (GPR55) and the tyrosine kinase receptor (TKR) human V-Erb-B2 Avian Erythroblastic Leukemia Viral Oncogene Homolog 2 (HER2). These protein complexes possess unique pharmacological and signaling properties, and their modulation might affect the antitumoral activity of the ECS. This review will explore the potential of the endocannabinoid network in the anti-cancer setting as well as the clinical and ethical pitfalls behind it, and will develop on the value of cannabinoid receptor heteromers as potential new targets for anti-cancer therapies and as prognostic biomarkers.
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Affiliation(s)
- Estefanía Moreno
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Milena Cavic
- Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Belgrade, Serbia
| | - Ana Krivokuca
- Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Belgrade, Serbia
| | - Vicent Casadó
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Enric Canela
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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16
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Cortés A, Casadó-Anguera V, Moreno E, Casadó V. The heterotetrameric structure of the adenosine A 1-dopamine D 1 receptor complex: Pharmacological implication for restless legs syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:37-78. [PMID: 31229177 DOI: 10.1016/bs.apha.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Dopaminergic and purinergic signaling play a pivotal role in neurological diseases associated with motor symptoms, including Parkinson's disease (PD), multiple sclerosis, amyotrophic lateral sclerosis, Huntington disease, Restless Legs Syndrome (RLS), spinal cord injury (SCI), and ataxias. Extracellular dopamine and adenosine exert their functions interacting with specific dopamine (DR) or adenosine (AR) receptors, respectively, expressed on the surface of target cells. These receptors are members of the family A of G protein-coupled receptors (GPCRs), which is the largest protein superfamily in mammalian genomes. GPCRs are target of about 40% of all current marketed drugs, highlighting their importance in clinical medicine. The striatum receives the densest dopamine innervations and contains the highest density of dopamine receptors. The modulatory role of adenosine on dopaminergic transmission depends largely on the existence of antagonistic interactions mediated by specific subtypes of DRs and ARs, the so-called A2AR-D2R and A1R-D1R interactions. Due to the dopamine/adenosine antagonism in the CNS, it was proposed that ARs and DRs could form heteromers in the neuronal cell surface. Therefore, adenosine can affect dopaminergic signaling through receptor-receptor interactions and by modulations in their shared intracellular pathways in the striatum and spinal cord. In this work we describe the allosteric modulations between GPCR protomers, focusing in those of adenosine and dopamine within the A1R-D1R heteromeric complex, which is involved in RLS. We also propose that the knowledge about the intricate allosteric interactions within the A1R-D1R heterotetramer, may facilitate the treatment of motor alterations, not only when the dopamine pathway is hyperactivated (RLS, chorea, etc.) but also when motor function is decreased (SCI, aging, PD, etc.).
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Affiliation(s)
- Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Verònica Casadó-Anguera
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Estefanía Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.
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17
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Sleno R, Hébert TE. Shaky ground - The nature of metastable GPCR signalling complexes. Neuropharmacology 2019; 152:4-14. [PMID: 30659839 DOI: 10.1016/j.neuropharm.2019.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/20/2018] [Accepted: 01/16/2019] [Indexed: 01/19/2023]
Abstract
How G protein-coupled receptors (GPCR) interact with one another remains an area of active investigation. Obligate dimers of class C GPCRs such as metabotropic GABA and glutamate receptors are well accepted, although whether this is a general feature of other GPCRs is still strongly debated. In this review, we focus on the idea that GPCR dimers and oligomers are better imagined as parts of larger metastable signalling complexes. We discuss the nature of functional oligomeric entities, their stabilities and kinetic features and how structural and functional asymmetries of such metastable entities might have implications for drug discovery. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.
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Affiliation(s)
- Rory Sleno
- Marketed Pharmaceuticals and Medical Devices Bureau, Marketed Health Products Directorate, Health Products and Food Branch, Health Canada, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Canada.
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18
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GPCR homo-oligomerization. Curr Opin Cell Biol 2018; 57:40-47. [PMID: 30453145 PMCID: PMC7083226 DOI: 10.1016/j.ceb.2018.10.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are an extensive class of trans-plasma membrane proteins that function to regulate a wide range of physiological functions. Despite a general perception that GPCRs exist as monomers an extensive literature has examined whether GPCRs can also form dimers and even higher-order oligomers, and if such organization influences various aspects of GPCR function, including cellular trafficking, ligand binding, G protein coupling and signalling. Here we focus on recent studies that employ approaches ranging from computational methods to single molecule tracking and both quantal brightness and fluorescence fluctuation measurements to assess the organization, stability and potential functional significance of dimers and oligomers within the class A, rhodopsin-like GPCR family.
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19
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Randáková A, Dolejší E, Rudajev V, Zimčík P, Doležal V, El-Fakahany EE, Jakubík J. Role of membrane cholesterol in differential sensitivity of muscarinic receptor subtypes to persistently bound xanomeline. Neuropharmacology 2018; 133:129-144. [PMID: 29407765 DOI: 10.1016/j.neuropharm.2018.01.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/03/2018] [Accepted: 01/21/2018] [Indexed: 01/24/2023]
Abstract
Xanomeline (3-(Hexyloxy)-4-(1-methyl-1,2,5,6-tetrahydropyridin-3-yl)-1,2,5-thiadiazole) is a muscarinic agonist that is considered to be functionally selective for the M1/M4 receptor subtypes. Part of xanomeline binding is resistant to washing. Wash-resistant xanomeline activates muscarinic receptors persistently, except for the M5 subtype. Mutation of leucine 6.46 to isoleucine at M1 or M4 receptors abolished persistent activation by wash-resistant xanomeline. Reciprocal mutation of isoleucine 6.46 to leucine at the M5 receptor made it sensitive to activation by wash-resistant xanomeline. Lowering of membrane cholesterol made M1 and M4 mutants and M5 wild type receptors sensitive to activation by wash-resistant xanomeline. Molecular docking revealed a cholesterol binding site in the groove between transmembrane helices 6 and 7. Molecular dynamics showed that interaction of cholesterol with this binding site attenuates receptor activation. We hypothesize that differences in cholesterol binding to this site between muscarinic receptor subtypes may constitute the basis for xanomeline apparent functional selectivity and may have notable therapeutic implications. Differences in receptor-membrane interactions, rather than in agonist-receptor interactions, represent a novel possibility to achieve pharmacological selectivity. Our findings may be applicable to other G protein coupled receptors.
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Affiliation(s)
- Alena Randáková
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Eva Dolejší
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Vladimír Rudajev
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Pavel Zimčík
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Vladimír Doležal
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Esam E El-Fakahany
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, MN 55455, USA
| | - Jan Jakubík
- Institute of Physiology Czech Academy of Sciences, 142 20 Prague, Czech Republic.
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20
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Burger WAC, Sexton PM, Christopoulos A, Thal DM. Toward an understanding of the structural basis of allostery in muscarinic acetylcholine receptors. J Gen Physiol 2018; 150:1360-1372. [PMID: 30190312 PMCID: PMC6168235 DOI: 10.1085/jgp.201711979] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/14/2018] [Indexed: 01/16/2023] Open
Abstract
Burger et al. summarize our mechanistic understanding of allostery in the prototypical GPCR, the muscarinic acetylcholine receptor. Recent breakthroughs and developments in structural biology have led to a spate of crystal structures for G protein–coupled receptors (GPCRs). This is the case for the muscarinic acetylcholine receptors (mAChRs) where inactive-state structures for four of the five subtypes and two active-state structures for one subtype are available. These mAChR crystal structures have provided new insights into receptor mechanisms, dynamics, and allosteric modulation. This is highly relevant to the mAChRs given that these receptors are an exemplar model system for the study of GPCR allostery. Allosteric mechanisms of the mAChRs are predominantly consistent with a two-state model, albeit with some notable recent exceptions. Herein, we discuss the mechanisms for positive and negative allosteric modulation at the mAChRs and compare and contrast these to evidence offered by pharmacological, biochemical, and computational approaches. This analysis provides insight into the fundamental pharmacological properties exhibited by GPCR allosteric modulators, such as enhanced subtype selectivity, probe dependence, and biased modulation while highlighting the current challenges that remain. Though complex, enhanced molecular understanding of allosteric mechanisms will have considerable influence on our understanding of GPCR activation and signaling and development of therapeutic interventions.
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Affiliation(s)
- Wessel A C Burger
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - David M Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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21
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Li Y, Shivnaraine RV, Huang F, Wells JW, Gradinaru CC. Ligand-Induced Coupling between Oligomers of the M 2 Receptor and the G i1 Protein in Live Cells. Biophys J 2018; 115:881-895. [PMID: 30131171 DOI: 10.1016/j.bpj.2018.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/23/2018] [Accepted: 08/02/2018] [Indexed: 02/07/2023] Open
Abstract
Uncertainty over the mechanism of signaling via G protein-coupled receptors (GPCRs) relates in part to questions regarding their supramolecular structure. GPCRs and heterotrimeric G proteins are known to couple as monomers under various conditions. Many GPCRs form oligomers under many of the same conditions, however, and the biological role of those complexes is unclear. We have used dual-color fluorescence correlation spectroscopy to identify oligomers of the M2 muscarinic receptor and of Gi1 in purified preparations and live Chinese hamster ovary cells. Measurements on differently tagged receptors (i.e., eGFP-M2 and mCherry-M2) and G proteins (i.e., eGFP-Gαi1β1γ2 and mCherry-Gαi1β1γ2) detected significant cross-correlations between the two fluorophores in each case, both in detergent micelles and in live cells, indicating that both the receptor and Gi1 can exist as homo-oligomers. Oligomerization of differently tagged Gi1 decreased upon the activation of co-expressed wild-type M2 receptor by an agonist. Measurements on a tagged M2 receptor (M2-mCherry) and eGFP-Gαi1β1γ2 co-expressed in live cells detected cross-correlations only in the presence of an agonist, which therefore promoted coupling of the receptor and the G protein. The effect of the agonist was retained when a fluorophore-tagged receptor lacking the orthosteric site (i.e., M2(D103A)-mCherry) was co-expressed with the wild-type receptor and eGFP-Gαi1β1γ2, indicating that the ligand acted via an oligomeric receptor. Our results point to a model in which an agonist promotes transient coupling of otherwise independent oligomers of the M2 receptor on the one hand and of Gi1 on the other and that an activated complex leads to a reduction in the oligomeric size of the G protein. They suggest that GPCR-mediated signaling proceeds, at least in part, via oligomers.
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Affiliation(s)
- Yuchong Li
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Fei Huang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - James W Wells
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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Xue Q, Bai B, Ji B, Chen X, Wang C, Wang P, Yang C, Zhang R, Jiang Y, Pan Y, Cheng B, Chen J. Ghrelin Through GHSR1a and OX1R Heterodimers Reveals a Gαs-cAMP-cAMP Response Element Binding Protein Signaling Pathway in Vitro. Front Mol Neurosci 2018; 11:245. [PMID: 30065627 PMCID: PMC6056640 DOI: 10.3389/fnmol.2018.00245] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 06/25/2018] [Indexed: 01/19/2023] Open
Abstract
Growth hormone secretagogue receptor 1α (GHSR1a) and Orexin 1 receptor (OX1R) are involved in various important physiological processes, and have many similar characteristics in function and distribution in peripheral tissues and the central nervous system. We explored the possibility of heterodimerization between GHSR1a and OX1R and revealed a signal transduction pathway mechanism. In this study, bioluminescence and fluorescence resonance energy transfer and co-immunoprecipitation (Co-IP) analyses were performed to demonstrate the formation of functional GHSR1a/OX1R heterodimers. This showed that a peptide corresponding to the 5-transmembrane domain of OX1R impaired heterodimer construction. We found that ghrelin stimulated GHSR1a/OX1R heterodimer cells to increase the activation of Gαs protein, compared to the cells that express GHSR1a. Stimulation of GHSR1a/OX1R heterodimers with orexin-A did not alter GPCR interactions with Gα protein subunits. GHSR1a/OX1R heterodimers induced Gαs and downstream signaling pathway activity, including increase of cAMP-response element luciferase reporter activity and cAMP levels. In addition, ghrelin induced a higher proliferation rate in SH-SY5Y cells than in controls. This suggests that ghrelin GHSR1a/OX1R heterodimers promotes an upregulation of a Gαs-cAMP-cAMP-responsive element signaling pathway in vitro and an increase in neuroblastoma cell proliferation.
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Affiliation(s)
- Qingjie Xue
- Neurobiology Institute, Jining Medical University, Jining, China.,Department of Pathogenic Biology, Jining Medical University, Jining, China
| | - Bo Bai
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Bingyuan Ji
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Xiaoyu Chen
- Department of Physiology, Taishan Medical University, Taian, China
| | - Chunmei Wang
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Peixiang Wang
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Chunqing Yang
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Rumin Zhang
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Yunlu Jiang
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Yanyou Pan
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Baohua Cheng
- Neurobiology Institute, Jining Medical University, Jining, China
| | - Jing Chen
- Neurobiology Institute, Jining Medical University, Jining, China.,Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
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23
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Oligomerization of a G protein-coupled receptor in neurons controlled by its structural dynamics. Sci Rep 2018; 8:10414. [PMID: 29991736 PMCID: PMC6039492 DOI: 10.1038/s41598-018-28682-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/26/2018] [Indexed: 12/16/2022] Open
Abstract
G protein coupled receptors (GPCRs) play essential roles in intercellular communication. Although reported two decades ago, the assembly of GPCRs into dimer and larger oligomers in their native environment is still a matter of intense debate. Here, using number and brightness analysis of fluorescently labeled receptors in cultured hippocampal neurons, we confirm that the metabotropic glutamate receptor type 2 (mGlu2) is a homodimer at expression levels in the physiological range, while heterodimeric GABAB receptors form larger complexes. Surprisingly, we observed the formation of larger mGlu2 oligomers upon both activation and inhibition of the receptor. Stabilizing the receptor in its inactive conformation using biochemical constraints also led to the observation of oligomers. Following our recent observation that mGlu receptors are in constant and rapid equilibrium between several states under basal conditions, we propose that this structural heterogeneity limits receptor oligomerization. Such assemblies are expected to stabilize either the active or the inactive state of the receptor.
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24
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Marsango S, Ward RJ, Alvarez-Curto E, Milligan G. Muscarinic receptor oligomerization. Neuropharmacology 2018; 136:401-410. [PMID: 29146505 PMCID: PMC6078712 DOI: 10.1016/j.neuropharm.2017.11.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 11/01/2017] [Accepted: 11/13/2017] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) have been classically described as monomeric entities that function by binding in a 1:1 stoichiometric ratio to both ligand and downstream signalling proteins. However, in recent years, a growing number of studies has supported the hypothesis that these receptors can interact to form dimers and higher order oligomers although the molecular basis for these interactions, the overall quaternary arrangements and the functional importance of GPCR oligomerization remain topics of intense speculation. Muscarinic acetylcholine receptors belong to class A of the GPCR family. Each muscarinic receptor subtype has its own particular distribution throughout the central and peripheral nervous systems. In the central nervous system, muscarinic receptors regulate several sensory, cognitive, and motor functions while, in the peripheral nervous system, they are involved in the regulation of heart rate, stimulation of glandular secretion and smooth muscle contraction. Muscarinic acetylcholine receptors have long been used as a model for the study of GPCR structure and function and to address aspects of GPCR dimerization using a broad range of approaches. In this review, the prevailing knowledge regarding the quaternary arrangement for the various muscarinic acetylcholine receptors has been summarized by discussing work ranging from initial results obtained using more traditional biochemical approaches to those generated with more modern biophysical techniques. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- Sara Marsango
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
| | - Richard J Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
| | - Elisa Alvarez-Curto
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Graeme Milligan
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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25
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Sleno R, Hébert TE. The Dynamics of GPCR Oligomerization and Their Functional Consequences. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:141-171. [PMID: 29699691 DOI: 10.1016/bs.ircmb.2018.02.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The functional importance of G protein-coupled receptor (GPCR) oligomerization remains controversial. Although obligate dimers of class C GPCRs are well accepted, the generalizability of this phenomenon is still strongly debated with respect to other classes of GPCRs. In this review, we focus on understanding the organization and dynamics between receptor equivalents and their signaling partners in oligomeric receptor complexes, with a view toward integrating disparate viewpoints into a unified understanding. We discuss the nature of functional oligomeric entities, and how asymmetries in receptor structure and function created by oligomers might have implications for receptor function as allosteric machines and for future drug discovery.
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26
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Pediani JD, Ward RJ, Marsango S, Milligan G. Spatial Intensity Distribution Analysis: Studies of G Protein-Coupled Receptor Oligomerisation. Trends Pharmacol Sci 2017; 39:175-186. [PMID: 29032835 PMCID: PMC5783713 DOI: 10.1016/j.tips.2017.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/04/2017] [Accepted: 09/14/2017] [Indexed: 02/08/2023]
Abstract
Spatial intensity distribution analysis (SpIDA) is a recently developed approach for determining quaternary structure information on fluorophore-labelled proteins of interest in situ. It can be applied to live or fixed cells and native tissue. Using confocal images, SpIDA generates fluorescence intensity histograms that are analysed by super-Poissonian distribution functions to obtain density and quantal brightness values of the fluorophore-labelled protein of interest. This allows both expression level and oligomerisation state of the protein to be determined. We describe the application of SpIDA to investigate the oligomeric state of G protein-coupled receptors (GPCRs) at steady state and following cellular challenge, and consider how SpIDA may be used to explore GPCR quaternary organisation in pathophysiology and to stratify medicines. GPCRs may exist and function as monomers: however, abundant evidence suggests they can form dimers/oligomers. This concept has implications for drug discovery as it may offer opportunities to modulate the effects of known pharmaceuticals or identify new drug therapies. A variety of approaches have been applied to this issue from traditional biochemical techniques, via resonance energy transfer approaches to recently developed image analysis-based techniques such as SpIDA. This uses mathematical analysis of confocal microscopy images to generate quantal brightness and density information for a fluorophore-tagged receptor. SpIDA can be applied to live or fixed cells and native tissue. SpIDA has been applied to GPCRs from each of the major subfamilies to explore their oligomerisation status at steady state and their regulation by receptor density and ligand binding.
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Affiliation(s)
- John D Pediani
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Richard J Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Sara Marsango
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Graeme Milligan
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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27
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Bartuzi D, Kaczor AA, Matosiuk D. Signaling within Allosteric Machines: Signal Transmission Pathways Inside G Protein-Coupled Receptors. Molecules 2017; 22:molecules22071188. [PMID: 28714871 PMCID: PMC6152049 DOI: 10.3390/molecules22071188] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 11/16/2022] Open
Abstract
In recent years, our understanding of function of G protein-coupled receptors (GPCRs) has changed from a picture of simple signal relays, transmitting only a particular signal to a particular G protein heterotrimer, to versatile machines, capable of various responses to different stimuli and being modulated by various factors. Some recent reports provide not only the data on ligands/modulators and resultant signals induced by them, but also deeper insights into exact pathways of signal migration and mechanisms of signal transmission through receptor structure. Combination of these computational and experimental data sheds more light on underlying mechanisms of signal transmission and signaling bias in GPCRs. In this review we focus on available clues on allosteric pathways responsible for complex signal processing within GPCRs structures, with particular emphasis on linking compatible in silico- and in vitro-derived data on the most probable allosteric connections.
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Affiliation(s)
- Damian Bartuzi
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin, 4A Chodźki Str., Lublin PL20093, Poland.
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin, 4A Chodźki Str., Lublin PL20093, Poland.
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1627, Kuopio FI-70211, Finland.
| | - Dariusz Matosiuk
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin, 4A Chodźki Str., Lublin PL20093, Poland.
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28
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Dual-agonist occupancy of orexin receptor 1 and cholecystokinin A receptor heterodimers decreases G-protein–dependent signaling and migration in the human colon cancer cell line HT-29. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1153-1164. [DOI: 10.1016/j.bbamcr.2017.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 01/14/2023]
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29
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Spatial intensity distribution analysis quantifies the extent and regulation of homodimerization of the secretin receptor. Biochem J 2017; 474:1879-1895. [PMID: 28424368 PMCID: PMC5442643 DOI: 10.1042/bcj20170184] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/02/2023]
Abstract
Previous studies have indicated that the G-protein-coupled secretin receptor is present as a homodimer, organized through symmetrical contacts in transmembrane domain IV, and that receptor dimerization is critical for high-potency signalling by secretin. However, whether all of the receptor exists in the dimeric form or if this is regulated is unclear. We used measures of quantal brightness of the secretin receptor tagged with monomeric enhanced green fluorescent protein (mEGFP) and spatial intensity distribution analysis to assess this. Calibration using cells expressing plasma membrane-anchored forms of mEGFP initially allowed us to demonstrate that the epidermal growth factor receptor is predominantly monomeric in the absence of ligand and while wild-type receptor was rapidly converted into a dimeric form by ligand, a mutated form of this receptor remained monomeric. Equivalent studies showed that, at moderate expression levels, the secretin receptor exists as a mixture of monomeric and dimeric forms, with little evidence of higher-order complexity. However, sodium butyrate-induced up-regulation of the receptor resulted in a shift from monomeric towards oligomeric organization. In contrast, a form of the secretin receptor containing a pair of mutations on the lipid-facing side of transmembrane domain IV was almost entirely monomeric. Down-regulation of the secretin receptor-interacting G-protein Gαs did not alter receptor organization, indicating that dimerization is defined specifically by direct protein–protein interactions between copies of the receptor polypeptide, while short-term treatment with secretin had no effect on organization of the wild-type receptor but increased the dimeric proportion of the mutated receptor variant.
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30
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Marsango S, Caltabiano G, Jiménez-Rosés M, Millan MJ, Pediani JD, Ward RJ, Milligan G. A Molecular Basis for Selective Antagonist Destabilization of Dopamine D 3 Receptor Quaternary Organization. Sci Rep 2017; 7:2134. [PMID: 28522847 PMCID: PMC5437050 DOI: 10.1038/s41598-017-02249-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/07/2017] [Indexed: 12/17/2022] Open
Abstract
The dopamine D3 receptor (D3R) is a molecular target for both first-generation and several recently-developed antipsychotic agents. Following stable expression of this mEGFP-tagged receptor, Spatial Intensity Distribution Analysis indicated that a substantial proportion of the receptor was present within dimeric/oligomeric complexes and that increased expression levels of the receptor favored a greater dimer to monomer ratio. Addition of the antipsychotics, spiperone or haloperidol, resulted in re-organization of D3R quaternary structure to promote monomerization. This action was dependent on ligand concentration and reversed upon drug washout. By contrast, a number of other antagonists with high affinity at the D3R, did not alter the dimer/monomer ratio. Molecular dynamics simulations following docking of each of the ligands into a model of the D3R derived from the available atomic level structure, and comparisons to the receptor in the absence of ligand, were undertaken. They showed that, in contrast to the other antagonists, spiperone and haloperidol respectively increased the atomic distance between reference α carbon atoms of transmembrane domains IV and V and I and II, both of which provide key interfaces for D3R dimerization. These results offer a molecular explanation for the distinctive ability of spiperone and haloperidol to disrupt D3R dimerization.
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Affiliation(s)
- Sara Marsango
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK.
| | - Gianluigi Caltabiano
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Mireia Jiménez-Rosés
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Mark J Millan
- Institut de Recherches Servier, Centre for Innovation in Neuropsychiatry, 125 Chemin de Ronde, Croissy sur Seine, France, 78290
| | - John D Pediani
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
| | - Richard J Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
| | - Graeme Milligan
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK.
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31
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Farran B. An update on the physiological and therapeutic relevance of GPCR oligomers. Pharmacol Res 2017; 117:303-327. [PMID: 28087443 DOI: 10.1016/j.phrs.2017.01.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/17/2023]
Abstract
The traditional view on GPCRs held that they function as single monomeric units composed of identical subunits. This notion was overturned by the discovery that GPCRs can form homo- and hetero-oligomers, some of which are obligatory, and can further assemble into receptor mosaics consisting of three or more protomers. Oligomerisation exerts significant impacts on receptor function and physiology, offering a platform for the diversification of receptor signalling, pharmacology, regulation, crosstalk, internalization and trafficking. Given their involvement in the modulation of crucial physiological processes, heteromers could constitute important therapeutic targets for a wide range of diseases, including schizophrenia, Parkinson's disease, substance abuse or obesity. This review aims at depicting the current developments in GPCR oligomerisation research, documenting various class A, B and C GPCR heteromers detected in vitro and in vivo using biochemical and biophysical approaches, as well as recently identified higher-order oligomeric complexes. It explores the current understanding of dimerization dynamics and the possible interaction interfaces that drive oligomerisation. Most importantly, it provides an inventory of the wide range of physiological processes and pathophysiological conditions to which GPCR oligomers contribute, surveying some of the oligomers that constitute potential drug targets. Finally, it delineates the efforts to develop novel classes of ligands that specifically target and tether to receptor oligomers instead of a single monomeric entity, thus ameliorating their ability to modulate GPCR function.
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Affiliation(s)
- Batoul Farran
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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32
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Quaternary structures of opsin in live cells revealed by FRET spectrometry. Biochem J 2016; 473:3819-3836. [PMID: 27623775 DOI: 10.1042/bcj20160422] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
Rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that initiates phototransduction in the retina. The receptor consists of the apoprotein opsin covalently linked to the inverse agonist 11-cis retinal. Rhodopsin and opsin have been shown to form oligomers within the outer segment disc membranes of rod photoreceptor cells. However, the physiological relevance of the observed oligomers has been questioned since observations were made on samples prepared from the retina at low temperatures. To investigate the oligomeric status of opsin in live cells at body temperatures, we utilized a novel approach called Förster resonance energy transfer spectrometry, which previously has allowed the determination of the stoichiometry and geometry (i.e. quaternary structure) of various GPCRs. In the current study, we have extended the method to additionally determine whether or not a mixture of oligomeric forms of opsin exists and in what proportion. The application of this improved method revealed that opsin expressed in live Chinese hamster ovary (CHO) cells at 37°C exists as oligomers of various sizes. At lower concentrations, opsin existed in an equilibrium of dimers and tetramers. The tetramers were in the shape of a near-rhombus. At higher concentrations of the receptor, higher-order oligomers began to form. Thus, a mixture of different oligomeric forms of opsin is present in the membrane of live CHO cells and oligomerization occurs in a concentration-dependent manner. The general principles underlying the concentration-dependent oligomerization of opsin may be universal and apply to other GPCRs as well.
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33
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Affiliation(s)
- Naomi R. Latorraca
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - A. J. Venkatakrishnan
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ron O. Dror
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
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