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Caniceiro AB, Bueschbell B, Schiedel AC, Moreira IS. Class A and C GPCR Dimers in Neurodegenerative Diseases. Curr Neuropharmacol 2022; 20:2081-2141. [PMID: 35339177 PMCID: PMC9886835 DOI: 10.2174/1570159x20666220327221830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 02/21/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.
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Affiliation(s)
- Ana B. Caniceiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Beatriz Bueschbell
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Irina S. Moreira
- University of Coimbra, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; ,Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal,Address correspondence to this author at the Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal; E-mail:
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Arjoune A, Sirard MA. The genomic response of human granulosa cells (KGN) to melatonin and specific agonists/antagonists to the melatonin receptors. Sci Rep 2022; 12:17539. [PMID: 36266374 PMCID: PMC9584952 DOI: 10.1038/s41598-022-21162-y] [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] [Received: 08/24/2022] [Accepted: 09/23/2022] [Indexed: 01/13/2023] Open
Abstract
Melatonin is a known modulator of follicle development; it acts through several molecular cascades via binding to its two specific receptors MT1 and MT2. Even though it is believed that melatonin can modulate granulosa cell (GC) functions, there is still limited knowledge of how it can act in human GC through MT1 and MT2 and which one is more implicated in the effects of melatonin on the metabolic processes in the dominant follicle. To better characterize the roles of these receptors on the effects of melatonin on follicular development, human granulosa-like tumor cells (KGN) were treated with specific melatonin receptor agonists and antagonists, and gene expression was analyzed with RNA-seq technology. Following appropriate normalization and the application of a fold change cut-off of 1.5 (FC 1.5, p ≤ 0.05) for each treatment, lists of the principal differentially expressed genes (DEGs) are generated. Analysis of major upstream regulators suggested that the MT1 receptor may be involved in the melatonin antiproliferative effect by reprogramming the metabolism of human GC by activating the PKB signaling pathway. Our data suggest that melatonin may act complementary through both MT1 and MT2 receptors to modulate human GC steroidogenesis, proliferation, and differentiation. However, MT2 receptors may be the ones implicated in transducing the effects of melatonin on the prevention of GC luteinization and follicle atresia at the antral follicular stage through stimulating the PKA pathway.
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Affiliation(s)
- Asma Arjoune
- grid.23856.3a0000 0004 1936 8390Centre de recherche en Reproduction, Développement et Santé Intergénérationnelle, Faculté des Sciences de L’agriculture et de l’alimentation, Département des Sciences animales, Université Laval, Québec, QC G1V 0A6 Canada ,grid.419508.10000 0001 2295 3249Department of Animal Production, National Agronomic Institute of Tunisia, University of Carthage, 43 Avenue Charles Nicolle, 1082 Mahrajène, Tunisia
| | - Marc-André Sirard
- grid.23856.3a0000 0004 1936 8390Centre de recherche en Reproduction, Développement et Santé Intergénérationnelle, Faculté des Sciences de L’agriculture et de l’alimentation, Département des Sciences animales, Université Laval, Québec, QC G1V 0A6 Canada
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3
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Momboisse F, Nardi G, Colin P, Hery M, Cordeiro N, Blachier S, Schwartz O, Arenzana-Seisdedos F, Sauvonnet N, Olivio-Marin JC, Lagane B, Lagache T, Brelot A. Tracking receptor motions at the plasma membrane reveals distinct effects of ligands on CCR5 dynamics depending on its dimerization status. eLife 2022; 11:76281. [PMID: 35866628 PMCID: PMC9307273 DOI: 10.7554/elife.76281] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 06/17/2022] [Indexed: 12/30/2022] Open
Abstract
G-protein-coupled receptors (GPCR) are present at the cell surface in different conformational and oligomeric states. However, how these states impact GPCRs biological function and therapeutic targeting remains incompletely known. Here, we investigated this issue in living cells for the CC chemokine receptor 5 (CCR5), a major receptor in inflammation and the principal entry co-receptor for Human Immunodeficiency Viruses type 1 (HIV-1). We used TIRF microscopy and a statistical method to track and classify the motion of different receptor subpopulations. We showed a diversity of ligand-free forms of CCR5 at the cell surface constituted of various oligomeric states and exhibiting transient Brownian and restricted motions. These forms were stabilized differently by distinct ligands. In particular, agonist stimulation restricted the mobility of CCR5 and led to its clustering, a feature depending on β-arrestin, while inverse agonist stimulation exhibited the opposite effect. These results suggest a link between receptor activation and immobilization. Applied to HIV-1 envelope glycoproteins gp120, our quantitative analysis revealed agonist-like properties of gp120s. Distinct gp120s influenced CCR5 dynamics differently, suggesting that they stabilize different CCR5 conformations. Then, using a dimerization-compromized mutant, we showed that dimerization (i) impacts CCR5 precoupling to G proteins, (ii) is a pre-requisite for the immobilization and clustering of receptors upon activation, and (iii) regulates receptor endocytosis, thereby impacting the fate of activated receptors. This study demonstrates that tracking the dynamic behavior of a GPCR is an efficient way to link GPCR conformations to their functions, therefore improving the development of drugs targeting specific receptor conformations.
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Affiliation(s)
- Fanny Momboisse
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Virus and Immunity Unit, Paris, France
| | - Giacomo Nardi
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, BioImage Analysis Unit, Paris, France
| | - Philippe Colin
- Infinity, Université de Toulouse, CNRS, INSERM, Toulouse, France
| | - Melanie Hery
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Virus and Immunity Unit, Paris, France
| | - Nelia Cordeiro
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Virus and Immunity Unit, Paris, France
| | - Simon Blachier
- Institut Pasteur, Université Paris Cité, Dynamics of Host-Pathogen Interactions Unit, Paris, France
| | - Olivier Schwartz
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Virus and Immunity Unit, Paris, France
| | | | - Nathalie Sauvonnet
- Institut Pasteur, Université Paris Cité, Group Intracellular Trafficking and Tissue Homeostasis, Paris, France
| | | | - Bernard Lagane
- Infinity, Université de Toulouse, CNRS, INSERM, Toulouse, France
| | - Thibault Lagache
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, BioImage Analysis Unit, Paris, France
| | - Anne Brelot
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Virus and Immunity Unit, Paris, France
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4
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Jeong E, Kim Y, Jeong J, Cho Y. Structure of the class C orphan GPCR GPR158 in complex with RGS7-Gβ5. Nat Commun 2021; 12:6805. [PMID: 34815401 PMCID: PMC8611064 DOI: 10.1038/s41467-021-27147-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/04/2021] [Indexed: 11/22/2022] Open
Abstract
GPR158, a class C orphan GPCR, functions in cognition, stress-induced mood control, and synaptic development. Among class C GPCRs, GPR158 is unique as it lacks a Venus flytrap-fold ligand-binding domain and terminates Gαi/o protein signaling through the RGS7-Gβ5 heterodimer. Here, we report the cryo-EM structures of GPR158 alone and in complex with one or two RGS7-Gβ5 heterodimers. GPR158 dimerizes through Per-Arnt-Sim-fold extracellular and transmembrane (TM) domains connected by an epidermal growth factor-like linker. The TM domain (TMD) reflects both inactive and active states of other class C GPCRs: a compact intracellular TMD, conformations of the two intracellular loops (ICLs) and the TMD interface formed by TM4/5. The ICL2, ICL3, TM3, and first helix of the cytoplasmic coiled-coil provide a platform for the DHEX domain of one RGS7 and the second helix recruits another RGS7. The unique features of the RGS7-binding site underlie the selectivity of GPR158 for RGS7.
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Affiliation(s)
- Eunyoung Jeong
- grid.49100.3c0000 0001 0742 4007Department of Life Science, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yoojoong Kim
- grid.49100.3c0000 0001 0742 4007Department of Life Science, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jihong Jeong
- grid.49100.3c0000 0001 0742 4007Department of Life Science, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yunje Cho
- Department of Life Science, Pohang University of Science and Technology, Pohang, Republic of Korea.
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Lépinay J, Taragnat C, Dubois JP, Chesneau D, Jockers R, Delagrange P, Bozon V. Negative regulation of melatonin secretion by melatonin receptors in ovine pinealocytes. PLoS One 2021; 16:e0255249. [PMID: 34324562 PMCID: PMC8320996 DOI: 10.1371/journal.pone.0255249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/12/2021] [Indexed: 01/01/2023] Open
Abstract
Melatonin (MLT) is a biological modulator of circadian and seasonal rhythms and reproduction. The photoperiodic information is detected by retinal photoreceptors and transmitted through nerve transmissions to the pineal gland, where MLT is synthesized and secreted at night into the blood. MLT interacts with two G protein-coupled receptors, MT1 and MT2. The aim of our work was to provide evidence for the presence of MLT receptors in the ovine pineal gland and define their involvement on melatonin secretion. For the first time, we identified the expression of MLT receptors with the specific 2-[125I]-MLT agonistic radioligand in ovin pinealocytes. The values of Kd and Bmax are 2.24 ± 1.1 nM and 20 ± 6.8 fmol/mg. MLT receptors are functional and inhibit cAMP production and activate ERK1/2 through pertussis toxin-sensitive Gi/o proteins. The MLT receptor antagonist/ inverse agonist luzindole increased cAMP production (189 ± 30%) and MLT secretion (866 ± 13%). The effect of luzindole on MLT secretion was additive with the effect of well-described activators of this pathway such as the β-adrenergic agonist isoproterenol and the α-adrenergic agonist phenylephrine. Co-incubation of all three compounds increased MLT secretion by 1236 ± 199%. These results suggest that MLT receptors are involved in the negative regulation of the synthesis of its own ligand in pinealocytes. While adrenergic receptors promote MLT secretion, MLT receptors mitigate this effect to limit the quantity of MLT secreted by the pineal gland.
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Affiliation(s)
- Julie Lépinay
- Physiologie de la Reproduction et des Comportements, Université de Tours, Nouzilly, France
| | - Catherine Taragnat
- Physiologie de la Reproduction et des Comportements, Université de Tours, Nouzilly, France
| | - Jean-Philippe Dubois
- Physiologie de la Reproduction et des Comportements, Université de Tours, Nouzilly, France
| | - Didier Chesneau
- Physiologie de la Reproduction et des Comportements, Université de Tours, Nouzilly, France
| | - Ralf Jockers
- Université de Paris, Institut Cochin, INSERM, CNRS, Paris, France
| | | | - Véronique Bozon
- Physiologie de la Reproduction et des Comportements, Université de Tours, Nouzilly, France
- * E-mail:
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Modulation of G-protein-coupled receptor 55-mediated signaling by regulator of G-protein signaling 2. Biochem Biophys Res Commun 2020; 533:1233-1239. [PMID: 33092790 DOI: 10.1016/j.bbrc.2020.09.123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/23/2020] [Accepted: 09/28/2020] [Indexed: 12/19/2022]
Abstract
Activation of seven-transmembrane G-protein coupled receptor (GPCR) mediates extracellular signals into intracellular responses. G-protein coupled receptor 55 (GPR55) is one of GPCRs and activated by endogenous cannabinoids. A family of regulators of G-protein signaling (RGS) stimulates GTP hydrolysis of alpha subunit of G-protein (Gα) and inhibits GPCR/Gα-mediated signaling. RGS2 is member of R4 RGS family and mainly attenuates GPCR/Gαq signaling. Although RGS2 is known to modulate some GPCR signaling, the specific effects of RGS2 on GPR55-mediated signaling are not fully understood at present. Previously, we reported some RGS proteins interact with protease-activated receptors, one of GPCRs, and modulate their functions. Here, we investigated whether GPR55 interacts with RGS2, employing bioluminescence resonance energy transfer and co-immunoprecipitation analyses. Interestingly, GPR55 interacted with RGS2 alone and also formed a ternary complex with RGS2 and either Gαq or Gα12. In the presence of GPR55 alone and together with Gαq or Gα12, RGS2 translocated from the cytoplasm to plasma membrane while RGS1 remained in the cytoplasm. GPR55 activation significantly induced ERK phosphorylation and intracellular calcium mobilization, which were markedly inhibited by RGS2 in HCT116 colon cancer cell line. Furthermore, GPR55-mediated cell proliferation and migration of HCT116 cells, was significantly attenuated by RGS2. Our collective findings highlight a novel physiological function of RGS2, supporting its utility as a therapeutic target to control GPR55-induced pathophysiology.
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7
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Lismont E, Verbakel L, Vogel E, Corbisier J, Degroot GN, Verdonck R, Verlinden H, Marchal E, Springael JY, Vanden Broeck J. Can BRET-based biosensors be used to characterize G-protein mediated signaling pathways of an insect GPCR, the Schistocerca gregaria CRF-related diuretic hormone receptor? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 122:103392. [PMID: 32387240 DOI: 10.1016/j.ibmb.2020.103392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/01/2020] [Accepted: 04/19/2020] [Indexed: 05/26/2023]
Abstract
G protein-coupled receptors (GPCRs) are membrane-bound receptors that are considered prime candidates for the development of novel insect pest management strategies. However, the molecular signaling properties of insect GPCRs remain poorly understood. In fact, most studies on insect GPCR signaling are limited to analysis of fluctuations in the secondary messenger molecules calcium (Ca2+) and/or cyclic adenosine monophosphate (cAMP). In the current study, we characterized a corticotropin-releasing factor-related diuretic hormone (CRF-DH) receptor of the desert locust, Schistocerca gregaria. This Schgr-CRF-DHR is mainly expressed in the nervous system and in brain-associated endocrine organs. The neuropeptide Schgr-CRF-DH induced Ca2+-dependent aequorin-based bioluminescent responses in CHO cells co-expressing this receptor with the promiscuous Gα16 protein. Furthermore, when co-expressed with the cAMP-dependent bioluminescence resonance energy transfer (BRET)-based CAMYEL biosensor in HEK293T cells, this receptor elicited dose-dependent agonist-induced responses with an EC50 in the nanomolar range (4.02 nM). In addition, we tested if vertebrate BRET-based G protein biosensors, can also be used to detect direct Gα protein subunit activation by an insect GPCR. Therefore, we analyzed ten different human BRET-based G protein biosensors, representing members of all four Gα protein subfamilies; Gαs, Gαi/o, Gαq/11 and Gα12/13. Our data demonstrate that stimulation of Schgr-CRF-DHR by Schgr-CRF-DH can dose-dependently activate Gαi/o and Gαs biosensors, while no significant effects were observed with the Gαq/11 and Gα12/13 biosensors. Our study paves the way for future biosensor-based studies to analyze the signaling properties of insect GPCRs in both fundamental science and applied research contexts.
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Affiliation(s)
- Els Lismont
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Lina Verbakel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium.
| | - Elise Vogel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | | | | | - Rik Verdonck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Heleen Verlinden
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Elisabeth Marchal
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium; Imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - Jean-Yves Springael
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM) Université Libre de Bruxelles (ULB), Campus Erasme, 808 Route de Lennik, B-1070, Brussels, Belgium
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
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Kim Y, Ghil S. Regulators of G-protein signaling, RGS2 and RGS4, inhibit protease-activated receptor 4-mediated signaling by forming a complex with the receptor and Gα in live cells. Cell Commun Signal 2020; 18:86. [PMID: 32517689 PMCID: PMC7285472 DOI: 10.1186/s12964-020-00552-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/11/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Protease-activated receptor 4 (PAR4) is a seven transmembrane G-protein coupled receptor (GPCR) activated by endogenous proteases, such as thrombin. PAR4 is involved in various pathophysiologies including cancer, inflammation, pain, and thrombosis. Although regulators of G-protein signaling (RGS) are known to modulate GPCR/Gα-mediated pathways, their specific effects on PAR4 are not fully understood at present. We previously reported that RGS proteins attenuate PAR1- and PAR2-mediated signaling through interactions with these receptors in conjunction with distinct Gα subunits. METHODS We employed a bioluminescence resonance energy transfer technique and confocal microscopy to examine potential interactions among PAR4, RGS, and Gα subunits. The inhibitory effects of RGS proteins on PAR4-mediated downstream signaling and cancer progression were additionally investigated by using several assays including ERK phosphorylation, calcium mobilization, RhoA activity, cancer cell proliferation, and related gene expression. RESULTS In live cells, RGS2 interacts with PAR4 in the presence of Gαq while RGS4 binding to PAR4 occurs in the presence of Gαq and Gα12/13. Co-expression of PAR4 and Gαq induced a shift in the subcellular localization of RGS2 and RGS4 from the cytoplasm to plasma membrane. Combined PAR4 and Gα12/13 expression additionally promoted translocation of RGS4 from the cytoplasm to the membrane. Both RGS2 and RGS4 abolished PAR4-activated ERK phosphorylation, calcium mobilization and RhoA activity, as well as PAR4-mediated colon cancer cell proliferation and related gene expression. CONCLUSIONS RGS2 and RGS4 forms ternary complex with PAR4 in Gα-dependent manner and inhibits its downstream signaling. Our findings support a novel physiological function of RGS2 and RGS4 as inhibitors of PAR4-mediated signaling through selective PAR4/RGS/Gα coupling. Video Abstract.
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Affiliation(s)
- Yukeyoung Kim
- Department of Life Science, Kyonggi University, Suwon, 16227, South Korea
| | - Sungho Ghil
- Department of Life Science, Kyonggi University, Suwon, 16227, South Korea.
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Legros C, Dupré C, Brasseur C, Bonnaud A, Bruno O, Valour D, Shabajee P, Giganti A, Nosjean O, Kenakin TP, Boutin JA. Characterization of the various functional pathways elicited by synthetic agonists or antagonists at the melatonin MT 1 and MT 2 receptors. Pharmacol Res Perspect 2020; 8:e00539. [PMID: 31893123 PMCID: PMC6935685 DOI: 10.1002/prp2.539] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 09/30/2019] [Accepted: 10/10/2019] [Indexed: 12/20/2022] Open
Abstract
Melatonin is a neurohormone that translates the circadian rhythm to the peripheral organs through a series of binding sites identified as G protein-coupled receptors MT1 and MT2. Due to minute amounts of receptor proteins in target organs, the main tool of studies of the melatoninergic system is recombinant expression of the receptors in cellular hosts. Although a number of studies exist on these receptors, studies of several signaling pathways using a large number of melatoninergic compounds are rather limited. We chose to fill this gap to better describe a panel of compounds that have been only partially characterized in terms of functionality. First, we characterized HEK cells expressing MT1 or MT2, and several signaling routes with melatonin itself to validate the approach: GTPγS, cAMP production, internalization, β-arrestin recruitment, and cell morphology changes (CellKey ® ). Second, we chose 21 compounds from our large melatoninergic chemical library and characterized them using this panel of signaling pathways. Notably, antagonists were infrequent, and their functionality depended largely on the pathway studied. This will permit redefining the availability of molecular tools that can be used to better understand the in situ activity and roles of these receptors.
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Affiliation(s)
- Céline Legros
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Clémence Dupré
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Chantal Brasseur
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Anne Bonnaud
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Olivier Bruno
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Damien Valour
- Pôle d’Expetise Méthodologie et Valorisation des DonnéesInstitut de Recherches Internationales ServierSuresnesFrance
| | - Preety Shabajee
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Adeline Giganti
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
| | - Olivier Nosjean
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
- Present address:
Institut de Recherches Internationales SERVIERSuresnesFrance
| | - Terrence P. Kenakin
- Department of PharmacologyUniversity of North Carolina School of MedicineChapel HillNCUSA
| | - Jean A. Boutin
- Pôle d’Expertise BiotechnologieChimie & BiologieInstitut de Recherches ServierCroissy‐sur‐SeineFrance
- Present address:
Institut de Recherches Internationales SERVIERSuresnesFrance
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Cecon E, Ivanova A, Luka M, Gbahou F, Friederich A, Guillaume JL, Keller P, Knoch K, Ahmad R, Delagrange P, Solimena M, Jockers R. Detection of recombinant and endogenous mouse melatonin receptors by monoclonal antibodies targeting the C-terminal domain. J Pineal Res 2019; 66:e12540. [PMID: 30475390 DOI: 10.1111/jpi.12540] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/04/2018] [Accepted: 11/16/2018] [Indexed: 02/06/2023]
Abstract
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non-24-hour sleep-wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2 , belonging to the G protein-coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2 . Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2 . None of the mABs cross-reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR-KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta-cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.
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Affiliation(s)
- Erika Cecon
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
| | - Anna Ivanova
- Molecular Diabetology, Faculty of Medicine, University Hospital, TU Dresden, Dresden, Germany
- Faculty of Medicine, Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Munich Neuherberg, Germany
| | - Marine Luka
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
| | - Florence Gbahou
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
| | - Anne Friederich
- Molecular Diabetology, Faculty of Medicine, University Hospital, TU Dresden, Dresden, Germany
- Faculty of Medicine, Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Munich Neuherberg, Germany
| | - Jean-Luc Guillaume
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
| | - Patrick Keller
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Klaus Knoch
- Molecular Diabetology, Faculty of Medicine, University Hospital, TU Dresden, Dresden, Germany
- Faculty of Medicine, Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Munich Neuherberg, Germany
| | - Raise Ahmad
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
| | - Philippe Delagrange
- Pôle d'Innovation Thérapeutique Neuropsychiatrie, Institut de Recherches Servier, Croissy, France
| | - Michele Solimena
- Molecular Diabetology, Faculty of Medicine, University Hospital, TU Dresden, Dresden, Germany
- Faculty of Medicine, Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Munich Neuherberg, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Ralf Jockers
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Sorbonne Paris Cité, Univ. Paris Descartes, Paris, France
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11
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Abstract
Despite considerable advances in the past few years, obesity and type 2 diabetes mellitus (T2DM) remain two major challenges for public health systems globally. In the past 9 years, genome-wide association studies (GWAS) have established a major role for genetic variation within the MTNR1B locus in regulating fasting plasma levels of glucose and in affecting the risk of T2DM. This discovery generated a major interest in the melatonergic system, in particular the melatonin MT2 receptor (which is encoded by MTNR1B). In this Review, we discuss the effect of melatonin and its receptors on glucose homeostasis, obesity and T2DM. Preclinical and clinical post-GWAS evidence of frequent and rare variants of the MTNR1B locus confirmed its importance in regulating glucose homeostasis and T2DM risk with minor effects on obesity. However, these studies did not solve the question of whether melatonin is beneficial or detrimental, an issue that will be discussed in the context of the peculiarities of the melatonergic system. Melatonin receptors might have therapeutic potential as they belong to the highly druggable G protein-coupled receptor superfamily. Clarifying the precise role of melatonin and its receptors on glucose homeostasis is urgent, as melatonin is widely used for other indications, either as a prescribed medication or as a supplement without medical prescription, in many countries in Europe and in the USA.
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Affiliation(s)
- Angeliki Karamitri
- Inserm, U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Université Sorbonne Paris Cité, Paris, France
| | - Ralf Jockers
- Inserm, U1016, Institut Cochin, Paris, France.
- CNRS UMR 8104, Paris, France.
- Université Paris Descartes, Université Sorbonne Paris Cité, Paris, France.
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12
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Clement N, Renault N, Guillaume J, Cecon E, Journé A, Laurent X, Tadagaki K, Cogé F, Gohier A, Delagrange P, Chavatte P, Jockers R. Importance of the second extracellular loop for melatonin MT 1 receptor function and absence of melatonin binding in GPR50. Br J Pharmacol 2018; 175:3281-3297. [PMID: 28898928 PMCID: PMC6057912 DOI: 10.1111/bph.14029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/09/2017] [Accepted: 09/03/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent crystal structures of GPCRs have emphasized the previously unappreciated role of the second extracellular (E2) loop in ligand binding and gating and receptor activation. Here, we have assessed the role of the E2 loop in the activation of the melatonin MT1 receptor and in the inactivation of the closely related orphan receptor GPR50. EXPERIMENTAL APPROACH Chimeric MT1 -GPR50 receptors were generated and functionally analysed in terms of 2-[125 I]iodomelatonin binding, Gi /cAMP signalling and β-arrestin2 recruitment. We also used computational molecular dynamics (MD) simulations. KEY RESULTS MD simulations of 300 ns revealed (i) the tight hairpin structure of the E2 loop of the MT1 receptor (ii) the most suitable features for melatonin binding in MT1 receptors and (iii) major predicted rearrangements upon MT1 receptor activation, stabilizing interaction networks between Phe179 or Gln181 in the E2 loop and transmembrane helixes 5 and 6. Functional assays confirmed these predictions, because reciprocal replacement of MT1 and GPR50 residues/domains led to the predicted loss- and gain-of-melatonin action of MT1 receptors and GPR50 respectively. CONCLUSIONS AND IMPLICATIONS Our work demonstrated the crucial role of the E2 loop for MT1 receptor and GPR50 function by proposing a model in which the E2 loop is important in stabilizing active MT1 receptor conformations and by showing how evolutionary processes appear to have selected for modifications in the E2 loop in order to make GPR50 unresponsive to melatonin. LINKED ARTICLES This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.
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Affiliation(s)
- Nathalie Clement
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Nicolas Renault
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Jean‐Luc Guillaume
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Erika Cecon
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Anne‐Sophie Journé
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Xavier Laurent
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Kenjiro Tadagaki
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Francis Cogé
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Arnaud Gohier
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Philippe Delagrange
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Philippe Chavatte
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Ralf Jockers
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
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13
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Cecon E, Oishi A, Jockers R. Melatonin receptors: molecular pharmacology and signalling in the context of system bias. Br J Pharmacol 2018; 175:3263-3280. [PMID: 28707298 PMCID: PMC6057902 DOI: 10.1111/bph.13950] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 12/15/2022] Open
Abstract
Melatonin, N-acetyl-5-methoxytryptamine, an evolutionally old molecule, is produced by the pineal gland in vertebrates, and it binds with high affinity to melatonin receptors, which are members of the GPCR family. Among the multiple effects attributed to melatonin, we will focus here on those that are dependent on the activation of the two mammalian MT1 and MT2 melatonin receptors. We briefly summarize the latest developments on synthetic melatonin receptor ligands, including multi-target-directed ligands, and the characterization of signalling-biased ligands. We discuss signalling pathways activated by melatonin receptors that appear to be highly cell- and tissue-dependent, emphasizing the impact of system bias on the functional outcome. Different proteins have been demonstrated to interact with melatonin receptors, and thus, we postulate that part of this system bias has its molecular basis in differences of the expression of receptor-associated proteins including heterodimerization partners. Finally, bias at the level of the receptor, by the expression of genetic receptor variants, will be discussed to show how a modified receptor function can have an effect on the risk for common diseases like type 2 diabetes in humans. LINKED ARTICLES: This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.
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Affiliation(s)
- Erika Cecon
- Institut CochinInserm, U1016ParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Atsuro Oishi
- Institut CochinInserm, U1016ParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Ralf Jockers
- Institut CochinInserm, U1016ParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
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14
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The orphan GPR50 receptor promotes constitutive TGFβ receptor signaling and protects against cancer development. Nat Commun 2018; 9:1216. [PMID: 29572483 PMCID: PMC5865211 DOI: 10.1038/s41467-018-03609-x] [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: 06/09/2017] [Accepted: 02/28/2018] [Indexed: 11/28/2022] Open
Abstract
Transforming growth factor-β (TGFβ) signaling is initiated by the type I, II TGFβ receptor (TβRI/TβRII) complex. Here we report the formation of an alternative complex between TβRI and the orphan GPR50, belonging to the G protein-coupled receptor super-family. The interaction of GPR50 with TβRI induces spontaneous TβRI-dependent Smad and non-Smad signaling by stabilizing the active TβRI conformation and competing for the binding of the negative regulator FKBP12 to TβRI. GPR50 overexpression in MDA-MB-231 cells mimics the anti-proliferative effect of TβRI and decreases tumor growth in a xenograft mouse model. Inversely, targeted deletion of GPR50 in the MMTV/Neu spontaneous mammary cancer model shows decreased survival after tumor onset and increased tumor growth. Low GPR50 expression is associated with poor survival prognosis in human breast cancer irrespective of the breast cancer subtype. This describes a previously unappreciated spontaneous TGFβ-independent activation mode of TβRI and identifies GPR50 as a TβRI co-receptor with potential impact on cancer development. Transforming growth factor-β (TGFβ) regulates many cellular processes. Here the authors show that the orphan G-protein coupled receptor GPR50 can activate the TGFβ receptor I, in the absence of TGFβ, by stabilizing its active conformation and show antitumor activity in a mouse model of breast cancer.
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15
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Dupré C, Bruno O, Bonnaud A, Giganti A, Nosjean O, Legros C, Boutin JA. Assessments of cellular melatonin receptor signaling pathways: β-arrestin recruitment, receptor internalization, and impedance variations. Eur J Pharmacol 2017; 818:534-544. [PMID: 29154938 DOI: 10.1016/j.ejphar.2017.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/03/2017] [Accepted: 11/13/2017] [Indexed: 12/30/2022]
Abstract
Melatonin receptors belong to the family of G-protein coupled receptors. Agonist-induced receptor activation is terminated with the recruitment of β-arrestin, which leads to receptor internalization. Furthermore, agonist binding induces a shift in cellular shape that translates into a change in the electric impedance of the cell. In the present study, we employed engineered cells to study these internalization-related processes in the context of the two melatonin receptors, MT1 and MT2. To assess these three receptor internalization-related functions and validate the results, we employed four classical ligands of melatonin receptors: the natural agonist melatonin; the super-agonist 2-iodo-melatonin and the two antagonists luzindole and 4-phenyl-2-propionamidotetralin. The assessments confirmed the nature of the agonistic ligands but showed that 4-phenyl-2-propionamidotetralin, a described antagonist, is a biased partial agonist at MT2 with poorer affinity for MT1. The methods are now available to be applied to any receptor system for which multiple signaling pathways must be evaluated for new molecules.
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Affiliation(s)
- Clémence Dupré
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Olivier Bruno
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Anne Bonnaud
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Adeline Giganti
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Olivier Nosjean
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Céline Legros
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France
| | - Jean A Boutin
- Pôle d'Expertise Biotechnologie, Chimie, Biologie, Institut de Recherches SERVIER, 125, Chemin De Ronde, 78290 Croissy-sur-Seine, France.
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16
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Signalling assemblies: the odds of symmetry. Biochem Soc Trans 2017; 45:599-611. [PMID: 28620024 DOI: 10.1042/bst20170009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 02/06/2023]
Abstract
The assembly of proteins into complexes is fundamental to nearly all biological signalling processes. Symmetry is a dominant feature of the structures of experimentally determined protein complexes, observed in the vast majority of homomers and many heteromers. However, some asymmetric structures exist, and asymmetry also often forms transiently, intractable to traditional structure determination methods. Here, we explore the role of protein complex symmetry and asymmetry in cellular signalling, focusing on receptors, transcription factors and transmembrane channels, among other signalling assemblies. We highlight a recurrent tendency for asymmetry to be crucial for signalling function, often being associated with activated states. We conclude with a discussion of how consideration of protein complex symmetry and asymmetry has significant potential implications and applications for pharmacology and human disease.
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17
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Sokolina K, Kittanakom S, Snider J, Kotlyar M, Maurice P, Gandía J, Benleulmi-Chaachoua A, Tadagaki K, Oishi A, Wong V, Malty RH, Deineko V, Aoki H, Amin S, Yao Z, Morató X, Otasek D, Kobayashi H, Menendez J, Auerbach D, Angers S, Pržulj N, Bouvier M, Babu M, Ciruela F, Jockers R, Jurisica I, Stagljar I. Systematic protein-protein interaction mapping for clinically relevant human GPCRs. Mol Syst Biol 2017; 13:918. [PMID: 28298427 PMCID: PMC5371730 DOI: 10.15252/msb.20167430] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
G‐protein‐coupled receptors (GPCRs) are the largest family of integral membrane receptors with key roles in regulating signaling pathways targeted by therapeutics, but are difficult to study using existing proteomics technologies due to their complex biochemical features. To obtain a global view of GPCR‐mediated signaling and to identify novel components of their pathways, we used a modified membrane yeast two‐hybrid (MYTH) approach and identified interacting partners for 48 selected full‐length human ligand‐unoccupied GPCRs in their native membrane environment. The resulting GPCR interactome connects 686 proteins by 987 unique interactions, including 299 membrane proteins involved in a diverse range of cellular functions. To demonstrate the biological relevance of the GPCR interactome, we validated novel interactions of the GPR37, serotonin 5‐HT4d, and adenosine ADORA2A receptors. Our data represent the first large‐scale interactome mapping for human GPCRs and provide a valuable resource for the analysis of signaling pathways involving this druggable family of integral membrane proteins.
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Affiliation(s)
- Kate Sokolina
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | | | - Jamie Snider
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Max Kotlyar
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Pascal Maurice
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Sorbonne Paris Cité, University of Paris Descartes, Paris, France.,UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Jorge Gandía
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Abla Benleulmi-Chaachoua
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Sorbonne Paris Cité, University of Paris Descartes, Paris, France
| | - Kenjiro Tadagaki
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Sorbonne Paris Cité, University of Paris Descartes, Paris, France
| | - Atsuro Oishi
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Sorbonne Paris Cité, University of Paris Descartes, Paris, France
| | - Victoria Wong
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Ramy H Malty
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK, Canada
| | - Viktor Deineko
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK, Canada
| | - Hiroyuki Aoki
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK, Canada
| | - Shahreen Amin
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK, Canada
| | - Zhong Yao
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Xavier Morató
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - David Otasek
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Hiroyuki Kobayashi
- Department of Biochemistry, Institute for Research in Immunology & Cancer, Université de Montréal, Montréal, QC, Canada
| | | | | | - Stephane Angers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Natasa Pržulj
- Department of Computing, University College London, London, UK
| | - Michel Bouvier
- Department of Biochemistry, Institute for Research in Immunology & Cancer, Université de Montréal, Montréal, QC, Canada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK, Canada
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Ralf Jockers
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Sorbonne Paris Cité, University of Paris Descartes, Paris, France
| | - Igor Jurisica
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada.,Departments of Medical Biophysics and Computer Science, University of Toronto, Toronto, ON, Canada.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, ON, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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18
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Vriend J, Liu W, Reiter RJ. The pineal gland: A model for adrenergic modulation of ubiquitin ligases. PLoS One 2017; 12:e0172441. [PMID: 28212404 PMCID: PMC5315301 DOI: 10.1371/journal.pone.0172441] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/04/2017] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION A recent study of the pineal gland of the rat found that the expression of more than 3000 genes showed significant day/night variations (The Hartley dataset). The investigators of this report made available a supplemental table in which they tabulated the expression of many genes that they did not discuss, including those coding for components of the ubiquitin proteasome system. Herein we identify the genes of the ubiquitin proteasome system whose expression were significantly influenced by environmental lighting in the Hartley dataset, those that were stimulated by DBcAMP in pineal glands in culture, and those that were stimulated by norepinephrine. PURPOSE Using the Ubiquitin and Ubiquitin-like Conjugation Database (UUCA) we identified ubiquitin ligases and conjugases, and deubiquitinases in the Hartley dataset for the purpose of determining whether expression of genes of the ubiquitin proteasome pathway were significantly influenced by day/night variations and if these variations were regulated by autonomic innervation of the pineal gland from the superior cervical ganglia. METHODS In the Hartley experiments pineal glands groups of rats sacrificed during the day and groups sacrificed during the night were examined for gene expression. Additional groups of rats had their superior cervical ganglia removed surgically or surgically decentralized and the pineal glands likewise examined for gene expression. RESULTS The genes with at least a 2-fold day/night significant difference in expression included genes for 5 ubiquitin conjugating enzymes, genes for 58 ubiquitin E3 ligases and genes for 6 deubiquitinases. A 35-fold day/night difference was noted in the expression of the gene Sik1, which codes for a protein containing both an ubiquitin binding domain (UBD) and an ubiquitin-associated (UBA) domain. Most of the significant differences in these genes were prevented by surgical removal, or disconnection, of the superior cervical ganglia, and most were responsive, in vitro, to treatment with a cyclic AMP analog, and norepinephrine. All previously described 24-hour rhythms in the pineal require an intact sympathetic input from the superior cervical ganglia. CONCLUSIONS The Hartley dataset thus provides evidence that the pineal gland is a highly useful model for studying adrenergically dependent mechanisms regulating variations in ubiquitin ligases, ubiquitin conjugases, and deubiquitinases, mechanisms that may be physiologically relevant not only in the pineal gland, but in all adrenergically innervated tissue.
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Affiliation(s)
- Jerry Vriend
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Wenjun Liu
- Department of Pathology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, Texas, United States of America
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19
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Daulat AM, Borg JP. Wnt/Planar Cell Polarity Signaling: New Opportunities for Cancer Treatment. Trends Cancer 2017; 3:113-125. [PMID: 28718442 DOI: 10.1016/j.trecan.2017.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/29/2016] [Accepted: 01/02/2017] [Indexed: 01/08/2023]
Abstract
Cancer cells are addicted to a large spectrum of extracellular cues implicated in initiation, stem cell renewal, tumor growth, dissemination in the body, and resistance to treatment. Wingless/Int-1 (Wnt) ligands and their associated signaling cascades contribute to most of these processes, paving the way for opportunities in therapeutic development. The developmental Wnt/planar cell polarity (PCP) pathway is the most recently described branch of Wnt signaling strongly implicated in cancer development at early and late stages. We describe here some of the latest knowledge accumulated on this pathway and the pending questions, present the most convincing findings about its role in cancer, and review the most promising strategies currently designed to target its components.
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Affiliation(s)
- Avais M Daulat
- Centre de Recherche en Cancérologie de Marseille, Aix Marseille Univ UM105, Inst Paoli-Calmettes, UMR7258 CNRS, U1068 INSERM, 'Cell Polarity, Cell Signalling, and Cancer - Equipe Labellisée Ligue Contre le Cancer', Marseille, France
| | - Jean-Paul Borg
- Centre de Recherche en Cancérologie de Marseille, Aix Marseille Univ UM105, Inst Paoli-Calmettes, UMR7258 CNRS, U1068 INSERM, 'Cell Polarity, Cell Signalling, and Cancer - Equipe Labellisée Ligue Contre le Cancer', Marseille, France.
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20
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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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21
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Yang L, Lee MMK, Leung MMH, Wong YH. Regulator of G protein signaling 20 enhances cancer cell aggregation, migration, invasion and adhesion. Cell Signal 2016; 28:1663-72. [PMID: 27495875 DOI: 10.1016/j.cellsig.2016.07.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/08/2016] [Accepted: 07/31/2016] [Indexed: 12/12/2022]
Abstract
Several RGS (regulator of G protein signaling) proteins are known to be upregulated in a variety of tumors but their roles in modulating tumorigenesis remain undefined. Since the expression of RGS20 is elevated in metastatic melanoma and breast tumors, we examined the effects of RGS20 overexpression and knockdown on the cell mobility and adhesive properties of different human cancer cell lines, including cervical cancer HeLa, breast adenocarcinoma MDA-MB-231, and non-small cell lung carcinoma H1299 and A549 cells. Expression of RGS20 enhanced cell aggregation, migration, invasion and adhesion as determined by hanging drop aggregation, wound healing, transwell chamber migration and invasion assays. Conversely, shRNA-mediated knockdown of endogenous RGS20 impaired these responses. In addition, RGS20 elevated the expression of vimentin (a mesenchymal cell marker) but down-regulated the expression of E-cadherin, two indicators commonly associated with metastasis. These results suggest that the expression of RGS20 may promote metastasis of tumor cells.
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Affiliation(s)
- Lei Yang
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Maggie M K Lee
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Manton M H Leung
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yung H Wong
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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22
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Boutin JA. Quinone reductase 2 as a promising target of melatonin therapeutic actions. Expert Opin Ther Targets 2015; 20:303-17. [DOI: 10.1517/14728222.2016.1091882] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jean A Boutin
- Institut de Recherches SERVIER, Pole d’Expertise Biotechnologie, Chimie & Biologie, 125, chemin de Ronde, 78290 Croissy-sur-Seine, France
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23
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Woodard GE, Jardín I, Berna-Erro A, Salido GM, Rosado JA. Regulators of G-protein-signaling proteins: negative modulators of G-protein-coupled receptor signaling. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:97-183. [PMID: 26008785 DOI: 10.1016/bs.ircmb.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Regulators of G-protein-signaling (RGS) proteins are a category of intracellular proteins that have an inhibitory effect on the intracellular signaling produced by G-protein-coupled receptors (GPCRs). RGS along with RGS-like proteins switch on through direct contact G-alpha subunits providing a variety of intracellular functions through intracellular signaling. RGS proteins have a common RGS domain that binds to G alpha. RGS proteins accelerate GTPase and thus enhance guanosine triphosphate hydrolysis through the alpha subunit of heterotrimeric G proteins. As a result, they inactivate the G protein and quickly turn off GPCR signaling thus terminating the resulting downstream signals. Activity and subcellular localization of RGS proteins can be changed through covalent molecular changes to the enzyme, differential gene splicing, and processing of the protein. Other roles of RGS proteins have shown them to not be solely committed to being inhibitors but behave more as modulators and integrators of signaling. RGS proteins modulate the duration and kinetics of slow calcium oscillations and rapid phototransduction and ion signaling events. In other cases, RGS proteins integrate G proteins with signaling pathways linked to such diverse cellular responses as cell growth and differentiation, cell motility, and intracellular trafficking. Human and animal studies have revealed that RGS proteins play a vital role in physiology and can be ideal targets for diseases such as those related to addiction where receptor signaling seems continuously switched on.
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Affiliation(s)
- Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Isaac Jardín
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - A Berna-Erro
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Gines M Salido
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Caceres, Spain
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24
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Valproic Acid Influences MTNR1A Intracellular Trafficking and Signaling in a β-Arrestin 2-Dependent Manner. Mol Neurobiol 2015; 53:1237-1246. [DOI: 10.1007/s12035-014-9085-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 12/29/2014] [Indexed: 10/24/2022]
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25
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Raveh A, Turecek R, Bettler B. Mechanisms of fast desensitization of GABA(B) receptor-gated currents. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:145-65. [PMID: 25637440 DOI: 10.1016/bs.apha.2014.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GABA(B) receptors (GABA(B)Rs) regulate the excitability of most neurons in the central nervous system by modulating the activity of enzymes and ion channels. In the sustained presence of the neurotransmitter γ-aminobutyric acid, GABA(B)Rs exhibit a time-dependent decrease in the receptor response-a phenomenon referred to as homologous desensitization. Desensitization prevents excessive receptor influences on neuronal activity. Much work focused on the mechanisms of GABA(B)R desensitization that operate at the receptor and control receptor expression at the plasma membrane. Over the past few years, it became apparent that GABA(B)Rs additionally evolved mechanisms for faster desensitization. These mechanisms operate at the G protein rather than at the receptor and inhibit G protein signaling within seconds of agonist exposure. The mechanisms for fast desensitization are ideally suited to regulate receptor-activated ion channel responses, which influence neuronal activity on a faster timescale than effector enzymes. Here, we provide an update on the mechanisms for fast desensitization of GABA(B)R responses and discuss physiological and pathophysiological implications.
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Affiliation(s)
- Adi Raveh
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Rostislav Turecek
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland; Department of Auditory Neuroscience, Institute of Experimental Medicine, ASCR, Prague, Czech Republic
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland.
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26
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Goupil E, Laporte SA, Hébert TE. GPCR heterodimers: asymmetries in ligand binding and signalling output offer new targets for drug discovery. Br J Pharmacol 2014; 168:1101-3. [PMID: 23121476 DOI: 10.1111/bph.12040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 10/26/2012] [Indexed: 11/29/2022] Open
Abstract
UNLABELLED Dimers of GPCRs have held the imagination of researchers for almost 20 years. However, only recently has their value as potentially novel drug targets been increased significantly, and primarily, in the context of GPCR heterodimers. The view of receptor heterodimers as allosteric machines has transformed the way we understand structural and functional asymmetries inherent in their organization. These asymmetries alter both signalling output and how they might be targeted pharmacologically. The paper in this issue of BJP by Siddiquee and colleagues () highlights our growing understanding of such asymmetries and their implications. They show that heterodimers of the angiotensin II AT1 receptor and the apelin receptor recognize and respond to their respective ligands in distinct ways from the parent receptors expressed alone. Further, they demonstrate asymmetric allosteric effects in the context of the heterodimer that may have significant implications for our understanding of such receptor complexes. LINKED ARTICLE This article is a commentary on the research paper by Siddiquee et al., pp. 1104-1117 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476-5381.2012.02192.x.
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Affiliation(s)
- Eugénie Goupil
- Department of Pharmacology and Theraputics, McGill University, Montréal, Québec, Canada
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27
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Tosini G, Owino S, Guillaume JL, Jockers R. Understanding melatonin receptor pharmacology: latest insights from mouse models, and their relevance to human disease. Bioessays 2014; 36:778-87. [PMID: 24903552 PMCID: PMC4151498 DOI: 10.1002/bies.201400017] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Melatonin, the neuro-hormone synthesized during the night, has recently seen an unexpected extension of its functional implications toward type 2 diabetes development, visual functions, sleep disturbances, and depression. Transgenic mouse models were instrumental for the establishment of the link between melatonin and these major human diseases. Most of the actions of melatonin are mediated by two types of G protein-coupled receptors, named MT1 and MT2 , which are expressed in many different organs and tissues. Understanding the pharmacology and function of mouse MT1 and MT2 receptors, including MT1 /MT2 heteromers, will be of crucial importance to evaluate the relevance of these mouse models for future therapeutic developments. This review will critically discuss these aspects, and give some perspectives including the generation of new mouse models.
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Affiliation(s)
- Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, GA, USA
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28
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Asymmetric perturbations of signalling oligomers. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 114:153-69. [PMID: 24650570 DOI: 10.1016/j.pbiomolbio.2014.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/26/2014] [Accepted: 03/04/2014] [Indexed: 01/06/2023]
Abstract
This review focuses on rapid and reversible noncovalent interactions for symmetric oligomers of signalling proteins. Symmetry mismatch, transient symmetry breaking and asymmetric perturbations via chemical (ligand binding) and physical (electric or mechanic) effects can initiate the signalling events. Advanced biophysical methods can reveal not only structural symmetries of stable membrane-bound signalling proteins but also asymmetric functional transition states. Relevant techniques amenable to distinguish between symmetric and asymmetric architectures are discussed including those with the capability of capturing low-populated transient conformational states. Typical examples of signalling proteins are overviewed for symmetry breaking in dimers (GPCRs, growth factor receptors, transcription factors); trimers (acid-sensing ion channels); tetramers (voltage-gated cation channels, ionotropic glutamate receptor, CNG and CHN channels); pentameric ligand-gated and mechanosensitive channels; higher order oligomers (gap junction channel, chaperonins, proteasome, virus capsid); as well as primary and secondary transporters. In conclusion, asymmetric perturbations seem to play important functional roles in a broad range of communicating networks.
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29
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Ferré S, Casadó V, Devi LA, Filizola M, Jockers R, Lohse MJ, Milligan G, Pin JP, Guitart X. G protein-coupled receptor oligomerization revisited: functional and pharmacological perspectives. Pharmacol Rev 2014; 66:413-34. [PMID: 24515647 DOI: 10.1124/pr.113.008052] [Citation(s) in RCA: 427] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Most evidence indicates that, as for family C G protein-coupled receptors (GPCRs), family A GPCRs form homo- and heteromers. Homodimers seem to be a predominant species, with potential dynamic formation of higher-order oligomers, particularly tetramers. Although monomeric GPCRs can activate G proteins, the pentameric structure constituted by one GPCR homodimer and one heterotrimeric G protein may provide a main functional unit, and oligomeric entities can be viewed as multiples of dimers. It still needs to be resolved if GPCR heteromers are preferentially heterodimers or if they are mostly constituted by heteromers of homodimers. Allosteric mechanisms determine a multiplicity of possible unique pharmacological properties of GPCR homomers and heteromers. Some general mechanisms seem to apply, particularly at the level of ligand-binding properties. In the frame of the dimer-cooperativity model, the two-state dimer model provides the most practical method to analyze ligand-GPCR interactions when considering receptor homomers. In addition to ligand-binding properties, unique properties for each GPCR oligomer emerge in relation to different intrinsic efficacy of ligands for different signaling pathways (functional selectivity). This gives a rationale for the use of GPCR oligomers, and particularly heteromers, as novel targets for drug development. Herein, we review the functional and pharmacological properties of GPCR oligomers and provide some guidelines for the application of discrete direct screening and high-throughput screening approaches to the discovery of receptor-heteromer selective compounds.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes on Drug Abuse, Department of Health and Human Services, 333 Cassell Drive, Baltimore, Maryland 21224.
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30
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Ayoub MA, Pin JP. Interaction of Protease-Activated Receptor 2 with G Proteins and β-Arrestin 1 Studied by Bioluminescence Resonance Energy Transfer. Front Endocrinol (Lausanne) 2013; 4:196. [PMID: 24391627 PMCID: PMC3869048 DOI: 10.3389/fendo.2013.00196] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 12/08/2013] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled receptors are well recognized as being able to activate several signaling pathways through the activation of different G proteins as well as other signaling proteins such as β-arrestins. Therefore, understanding how such multiple GPCR-mediated signaling can be integrated constitute an important aspect. Here, we applied bioluminescence resonance energy transfer (BRET) to shed more light on the G protein coupling profile of trypsin receptor, or protease-activated receptor 2 (PAR2), and its interaction with β-arrestin1. Using YFP and Rluc fusion constructs expressed in COS-7 cells, BRET data revealed a pre-assembly of PAR2 with both Gαi1 and Gαo and a rapid and transient activation of these G proteins upon receptor activation. In contrast, no pre-assembly of PAR2 with Gα12 could be detected and their physical association can be measured with a very slow and sustained kinetics similar to that of β-arrestin1 recruitment. These data demonstrate the coupling of PAR2 with Gαi1, Gαo, and Gα12 in COS-7 cells with differences in the kinetics of GPCR-G protein coupling, a parameter that very likely influences the cellular response. Moreover, this further illustrates that pre-assembly or agonist-induced G protein interaction depends on receptor-G protein pairs indicating another level of complexity and regulation of the signaling of GPCR-G protein complexes and its multiplicity.
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Affiliation(s)
- Mohammed Akli Ayoub
- Département de Pharmacologie Moléculaire, Institut de Génomique Fonctionnelle, Montpellier, France
- UMR5203, Centre national de la recherche scientifique, Universités Montpellier 1 & 2, Montpellier, France
- U661, Institut national de la santé et de la recherche médicale, Universités Montpellier 1 & 2, Montpellier, France
| | - Jean-Philippe Pin
- Département de Pharmacologie Moléculaire, Institut de Génomique Fonctionnelle, Montpellier, France
- UMR5203, Centre national de la recherche scientifique, Universités Montpellier 1 & 2, Montpellier, France
- U661, Institut national de la santé et de la recherche médicale, Universités Montpellier 1 & 2, Montpellier, France
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31
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Single-molecule imaging revealed dynamic GPCR dimerization. Curr Opin Cell Biol 2013; 27:78-86. [PMID: 24480089 DOI: 10.1016/j.ceb.2013.11.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 11/24/2013] [Indexed: 11/24/2022]
Abstract
Single fluorescent-molecule video imaging and tracking in living cells are revolutionizing our understanding of molecular interactions in the plasma membrane and intracellular membrane systems. They have revealed that molecular interactions occur surprisingly dynamically on much shorter time scales (≪1s) than those expected from the results by conventional techniques, such as pull-down assays (minutes to hours). Single-molecule imaging has unequivocally showed that G-protein-coupled receptors (GPCRs) undergo dynamic equilibrium between monomers and dimers, by enabling the determination of the 2D monomer-dimer equilibrium constant, the dimer dissociation rate constant (typically ∼10s(-1)), and the formation rate constant. Within one second, GPCRs typically undergo several cycles of monomer and homo-dimer formation with different partners.
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32
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Benleulmi-Chaachoua A, Wojciech S, Jockers R. [G protein-coupled receptors in the spot light]. Biol Aujourdhui 2013; 207:191-200. [PMID: 24330972 DOI: 10.1051/jbio/2013014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Indexed: 06/03/2023]
Abstract
G protein-coupled receptors (GPCRs), also known as seven transmembrane domain-spanning proteins (7TM), play an important role in tissue homeostasis and cellular and hormonal communication. GPCRs are targeted by a large panel of natural ligands such as photons, ions, metabolites, lipids and proteins but also by numerous drugs. Research efforts in the GPCR field have been rewarded in 2012 by the Nobel Price in Chemistry. The present article briefly summarizes our current knowledge on GPCRs and discusses future challenges in terms of fundamental aspects and therapeutic applications.
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Affiliation(s)
- Abla Benleulmi-Chaachoua
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, 12 rue de l'École de Médecine, 75006 Paris, France
| | - Stefanie Wojciech
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, 12 rue de l'École de Médecine, 75006 Paris, France
| | - Ralf Jockers
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, 12 rue de l'École de Médecine, 75006 Paris, France
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33
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Zlotos DP, Jockers R, Cecon E, Rivara S, Witt-Enderby PA. MT1 and MT2 Melatonin Receptors: Ligands, Models, Oligomers, and Therapeutic Potential. J Med Chem 2013; 57:3161-85. [DOI: 10.1021/jm401343c] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Darius. P. Zlotos
- Department
of Pharmaceutical Chemistry, The German University in Cairo, New Cairo City, 11835 Cairo, Egypt
| | - Ralf Jockers
- Inserm, U1016,
Institut Cochin, Paris, France
- CNRS UMR
8104, Paris, France
- Univ. Paris Descartes, Sorbonne Paris Cite, Paris, France
| | - Erika Cecon
- Department
of Physiology, Institute of Bioscience, University of Sao Paulo, Sao Paulo 05508-090, Brazil
| | - Silvia Rivara
- Dipartimento
di Farmacia, Università degli Studi di Parma, Parco Area
delle Scienze 27/A, 43124 Parma, Italy
| | - Paula A. Witt-Enderby
- Division
of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 421 Mellon Hall, Pittsburgh, Pennsylvania 15282, United States
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34
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Melatonin receptor genes in vertebrates. Int J Mol Sci 2013; 14:11208-23. [PMID: 23712359 PMCID: PMC3709728 DOI: 10.3390/ijms140611208] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/28/2013] [Accepted: 05/20/2013] [Indexed: 01/06/2023] Open
Abstract
Melatonin receptors are members of the G protein-coupled receptor (GPCR) family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A) and MT2 (or Mel1b or MTNR1B) receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C), has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.
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35
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Melatonin and pancreatic islets: interrelationships between melatonin, insulin and glucagon. Int J Mol Sci 2013; 14:6981-7015. [PMID: 23535335 PMCID: PMC3645673 DOI: 10.3390/ijms14046981] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 12/15/2022] Open
Abstract
The pineal hormone melatonin exerts its influence in the periphery through activation of two specific trans-membrane receptors: MT1 and MT2. Both isoforms are expressed in the islet of Langerhans and are involved in the modulation of insulin secretion from β-cells and in glucagon secretion from α-cells. De-synchrony of receptor signaling may lead to the development of type 2 diabetes. This notion has recently been supported by genome-wide association studies identifying particularly the MT2 as a risk factor for this rapidly spreading metabolic disturbance. Since melatonin is secreted in a clearly diurnal fashion, it is safe to assume that it also has a diurnal impact on the blood-glucose-regulating function of the islet. This factor has hitherto been underestimated; the disruption of diurnal signaling within the islet may be one of the most important mechanisms leading to metabolic disturbances. The study of melatonin–insulin interactions in diabetic rat models has revealed an inverse relationship: an increase in melatonin levels leads to a down-regulation of insulin secretion and vice versa. Elucidation of the possible inverse interrelationship in man may open new avenues in the therapy of diabetes.
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36
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Santoro R, Mori F, Marani M, Grasso G, Cambria MA, Blandino G, Muti P, Strano S. Blockage of melatonin receptors impairs p53-mediated prevention of DNA damage accumulation. Carcinogenesis 2013; 34:1051-61. [PMID: 23354312 DOI: 10.1093/carcin/bgt025] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Melatonin has been known to be a chemopreventive agent since its levels inversely correlate with the risk of developing cancer. We have recently shown that melatonin induces p38-dependent phosphorylation of both p53 and histone H2AX. This is associated with a p53-mediated increase in repair of both endogenous and chemotherapy-induced DNA damage. In addition, the inhibition of p38 activities impairs melatonin's capability to induce a p53-dependent DNA damage response and thus its ability to maintain genome integrity. Since melatonin-induced p53 phosphorylation requires an intact p38 phosphorylation cascade and p38 can be activated by G proteins, we supposed that melatonin's activities could be mediated by its G-protein-coupled membrane receptors, MT1 and MT2. Here, we show that the activation of the p53-dependent DNA damage response by melatonin is indeed mediated by MT1 and MT2. As a result, the absence of either receptor impairs melatonin's ability to reduce both cell proliferation and clonogenic potential of cancer cells. In addition, this causes an impairment of the p53-dependent DNA damage response. By providing molecular insight, our findings might have translational impact, suggesting the involvement of melatonin receptors in tumorigenesis.
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Affiliation(s)
- Raffaela Santoro
- Molecular Chemoprevention Group, Molecular Medicine Area, Regina Elena National Cancer Institute, Rome 00144, Italy
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37
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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]
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38
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Kniazeff J, Pin JP. Des dimères et des oligomères de récepteurs couplés aux protéines G, oui mais pourquoi ? Med Sci (Paris) 2012; 28:858-63. [DOI: 10.1051/medsci/20122810014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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39
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Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling. Proc Natl Acad Sci U S A 2012; 109:16342-7. [PMID: 22988116 DOI: 10.1073/pnas.1205838109] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The eight metabotropic glutamate receptors (mGluRs) are key modulators of synaptic transmission and are considered promising targets for the treatment of various brain disorders. Whereas glutamate acts at a large extracellular domain, allosteric modulators have been identified that bind to the seven transmembrane domain (7TM) of these dimeric G-protein-coupled receptors (GPCRs). We show here that the dimeric organization of mGluRs is required for the modulation of active and inactive states of the 7TM by agonists, but is not necessary for G-protein activation. Monomeric mGlu2, either as an isolated 7TM or in full-length, purified and reconstituted into nanodiscs, couples to G proteins upon direct activation by a positive allosteric modulator. However, only a reconstituted full-length dimeric mGlu2 activates G protein upon glutamate binding, suggesting that dimerization is required for glutamate induced activation. These data show that, even for such well characterized GPCR dimers like mGluR2, a single 7TM is sufficient for G-protein coupling. Despite this observation, the necessity of dimeric architecture for signaling induced by the endogenous ligand glutamate confirms that the central core of signaling complex is dimeric.
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40
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Devavry S, Legros C, Brasseur C, Delagrange P, Spadoni G, Cohen W, Malpaux B, Boutin JA, Nosjean O. Description of the constitutive activity of cloned human melatonin receptors hMT(1) and hMT(2) and discovery of inverse agonists. J Pineal Res 2012; 53:29-37. [PMID: 22017484 DOI: 10.1111/j.1600-079x.2011.00968.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Melatonin receptors have been described to activate different G protein-dependent signaling pathways, both in laboratory, heterologous, cellular models and in physiological conditions. Furthermore, the constitutive activity of G protein-coupled receptors has been shown to be key in physiological and pathological conditions. In the case of melatonin receptors, information is rather scare and concerns only MT1 receptors. In the present report, we show that the G protein-coupled melatonin receptors do have a constitutive, nonmelatonin-induced signaling activity using two cellular models of different origins, the Chinese hamster ovary cell line and Neuro2A, a neuroblastoma cell line. Furthermore, we show that this constitutive activity involves mainly Gi proteins, which is consistent with the common knowledge on the melatonin receptors. Importantly, we also describe, for the first time, inverse agonist properties for melatonin ligands. Although it is clear than more in-depth, biochemistry-based studies will be required to better understand by which pathway(s) the constitutively active melatonin receptors transfer melatonin information into intracellular biochemical events; our data open interesting perspectives for understanding the importance of the constitutive activity of melatonin receptors in physiological conditions.
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MESH Headings
- Animals
- CHO Cells
- Cloning, Molecular
- Cricetinae
- Cricetulus
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Melatonin/metabolism
- Receptor, Melatonin, MT1/agonists
- Receptor, Melatonin, MT1/genetics
- Receptor, Melatonin, MT1/metabolism
- Receptor, Melatonin, MT2/agonists
- Receptor, Melatonin, MT2/genetics
- Receptor, Melatonin, MT2/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- Séverine Devavry
- INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly, France
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41
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Teichmann A, Rutz C, Kreuchwig A, Krause G, Wiesner B, Schülein R. The Pseudo signal peptide of the corticotropin-releasing factor receptor type 2A prevents receptor oligomerization. J Biol Chem 2012; 287:27265-74. [PMID: 22689579 DOI: 10.1074/jbc.m112.360594] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-terminal signal peptides mediate the interaction of native proteins with the translocon complex of the endoplasmic reticulum membrane and are cleaved off during early protein biogenesis. The corticotropin-releasing factor receptor type 2a (CRF(2(a))R) possesses an N-terminal pseudo signal peptide, which represents a so far unique domain within the large protein family of G protein-coupled receptors (GPCRs). In contrast to a conventional signal peptide, the pseudo signal peptide remains uncleaved and consequently forms a hydrophobic extension at the N terminus of the receptor. The functional consequence of the presence of the pseudo signal peptide is not understood. Here, we have analyzed the significance of this domain for receptor dimerization/oligomerization in detail. To this end, we took the CRF(2(a))R and the homologous corticotropin-releasing factor receptor type 1 (CRF(1)R) possessing a conventional cleaved signal peptide and conducted signal peptide exchange experiments. Using single cell and single molecule imaging methods (fluorescence resonance energy transfer and fluorescence cross-correlation spectroscopy, respectively) as well as biochemical experiments, we obtained two novel findings; we could show that (i) the CRF(2(a))R is expressed exclusively as a monomer, and (ii) the presence of the pseudo signal peptide prevents its oligomerization. Thus, we have identified a novel functional domain within the GPCR protein family, which plays a role in receptor oligomerization and which may be useful to study the functional significance of this process in general.
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Affiliation(s)
- Anke Teichmann
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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42
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Shivnaraine RV, Huang XP, Seidenberg M, Ellis J, Wells JW. Heterotropic cooperativity within and between protomers of an oligomeric M(2) muscarinic receptor. Biochemistry 2012; 51:4518-40. [PMID: 22551249 DOI: 10.1021/bi3000287] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
At least four allosteric sites have been found to mediate the dose-dependent effects of gallamine on the binding of [(3)H]quinuclidinylbenzilate (QNB) and N-[(3)H]methylscopolamine (NMS) to M(2) muscarinic receptors in membranes and solubilized preparations from porcine atria, CHO cells, and Sf9 cells. The rate of dissociation of [(3)H]QNB was affected in a bell-shaped manner with at least one Hill coefficient (n(H)) greater than 1, indicating that at least three allosteric sites are involved. The level of binding of [(3)H]QNB was decreased in a biphasic manner, revealing at least two allosteric sites; binding of [(3)H]NMS was affected in a triphasic, serpentine manner, revealing at least three sites, and values of n(H) >1 pointed to at least four sites. Several lines of evidence indicate that all effects of gallamine were allosteric in nature and could be observed at equilibrium. The rates of equilibration and dissociation suggest that the receptor was predominately oligomeric, and the heterogeneity revealed by gallamine can be attributed to differences in its affinity for the constituent protomers of a tetramer. Those differences appear to arise from inter- and intramolecular cooperativity between gallamine and the radioligand.
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Affiliation(s)
- Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
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43
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Lohse MJ, Nuber S, Hoffmann C. Fluorescence/bioluminescence resonance energy transfer techniques to study G-protein-coupled receptor activation and signaling. Pharmacol Rev 2012; 64:299-336. [PMID: 22407612 DOI: 10.1124/pr.110.004309] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Fluorescence and bioluminescence resonance energy transfer (FRET and BRET) techniques allow the sensitive monitoring of distances between two labels at the nanometer scale. Depending on the placement of the labels, this permits the analysis of conformational changes within a single protein (for example of a receptor) or the monitoring of protein-protein interactions (for example, between receptors and G-protein subunits). Over the past decade, numerous such techniques have been developed to monitor the activation and signaling of G-protein-coupled receptors (GPCRs) in both the purified, reconstituted state and in intact cells. These techniques span the entire spectrum from ligand binding to the receptors down to intracellular second messengers. They allow the determination and the visualization of signaling processes with high temporal and spatial resolution. With these techniques, it has been demonstrated that GPCR signals may show spatial and temporal patterning. In particular, evidence has been provided for spatial compartmentalization of GPCRs and their signals in intact cells and for distinct physiological consequences of such spatial patterning. We review here the FRET and BRET technologies that have been developed for G-protein-coupled receptors and their signaling proteins (G-proteins, effectors) and the concepts that result from such experiments.
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Affiliation(s)
- Martin J Lohse
- Institute of Pharmacology and Toxicology, Versbacher Str. 9, 97078 Würzburg, Germany.
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44
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Paskaradevan S, Scott IC. The Aplnr GPCR regulates myocardial progenitor development via a novel cell-non-autonomous, Gα(i/o) protein-independent pathway. Biol Open 2012; 1:275-85. [PMID: 23213418 PMCID: PMC3507289 DOI: 10.1242/bio.2012380] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Myocardial progenitor development involves the migration of cells to the anterior lateral plate mesoderm (ALPM) where they are exposed to the necessary signals for heart development to proceed. Whether the arrival of cells to this location is sufficient, or whether earlier signaling events are required, for progenitor development is poorly understood. Here we demonstrate that in the absence of Aplnr signaling, cells fail to migrate to the heart-forming region of the ALPM. Our work uncovers a previously uncharacterized cell-non-autonomous function for Aplnr signaling in cardiac development. Furthermore, we show that both the single known Aplnr ligand, Apelin, and the canonical Gαi/o proteins that signal downstream of Aplnr are dispensable for Aplnr function in the context of myocardial progenitor development. This novel Aplnr signal can be substituted for by activation of Gata5/Smarcd3 in myocardial progenitors, suggesting a novel mechanism for Aplnr signaling in the establishment of a niche required for the proper migration/development of myocardial progenitor cells.
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Affiliation(s)
- Sivani Paskaradevan
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 555 University Avenue , Toronto, ON M5G 1X8 , Canada ; Department of Molecular Genetics, University of Toronto , Toronto, ON M5S 1A8 , Canada
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45
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Tadagaki K, Jockers R, Kamal M. History and biological significance of GPCR heteromerization in the neuroendocrine system. Neuroendocrinology 2012; 95:223-31. [PMID: 22156565 DOI: 10.1159/000330000] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/07/2011] [Indexed: 12/18/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute a large family of seven transmembrane proteins that regulate major cellular functions. The important role of GPCRs in the neuroendocrine system is outlined by the great interest of pharmaceutical companies in developing new drugs targeting these receptors. GPCRs exist as monomers, but can also be organized in oligomeric structures composed of either homo- or heteromers. GPCR heteromerization may play an important role in modulating and fine-tuning GPCR function and signaling. The literature reports many examples of GPCR heteromers in vitro raising the question of the physiological relevance of these complexes in tissues. Considerable efforts are currently being directed towards conclusive evidence for the existence of GPCRs heteromers in vivo, a crucial step for the validation of the concept of GPCR heteromerization and future drug development. The present review will give a brief history of GPCR oligomerization and emphasize the importance and physiological relevance of GPCR heteromerization by discussing key examples of GPCR couples.
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Affiliation(s)
- Kenjiro Tadagaki
- Inserm, U1016, Institut Cochin, CNRS UMR 8104, Université Paris Descartes, Paris, France
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46
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Maurice P, Benleulmi-Chaachoua A, Jockers R. Differential assembly of GPCR signaling complexes determines signaling specificity. Subcell Biochem 2012; 63:225-40. [PMID: 23161141 DOI: 10.1007/978-94-007-4765-4_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent proteomic and biochemical evidence indicates that cellular -signaling is organized in protein modules. G protein-coupled receptors (GPCRs) are privileged entry points for extracellular signals that are transmitted through the plasma membrane into the cell. The adequate cellular response and signaling specificity is regulated by GPCR-associated protein modules. The composition of these modules is dynamic and might depend on receptor stimulation, the proteome of a given cellular context, the subcellular localization of receptor-associated modules, the formation of GPCR oligomers and the variation of expression levels of components of these modules under physiological, for example circadian rhythm, or pathological conditions. The current article will highlight the importance of GPCR-associated protein modules as a biochemical basis for signaling specificity.
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Affiliation(s)
- Pascal Maurice
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014, Paris, France
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47
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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.
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48
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Carbajo-Pescador S, García-Palomo A, Martín-Renedo J, Piva M, González-Gallego J, Mauriz JL. Melatonin modulation of intracellular signaling pathways in hepatocarcinoma HepG2 cell line: role of the MT1 receptor. J Pineal Res 2011; 51:463-71. [PMID: 21718361 DOI: 10.1111/j.1600-079x.2011.00910.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Melatonin reduces proliferation in many different cancer cell lines. However, studies on the oncostatic effects of melatonin in hepatocarcinoma are limited. We have previously demonstrated that melatonin administration induces cycle arrest, apoptosis, and changes in the expression of its specific receptors in HepG2 human hepatocarcinoma cells. In this study, we used the receptor antagonist luzindole to assess the contribution of MT1 melatonin membrane receptor to melatonin effects on cell viability, mitogen-activated protein kinase (MAPKs) activation, and cAMP levels. Additionally, effects of MT1 inhibition on mRNA levels of cytosolic quinone reductase type-2 (NQO2) receptor and nuclear retinoic acid-related orphan receptor alpha (RORα) were tested. Melatonin, at 1000 and 2500 μm, significantly reduced cell viability. Pre-incubation with luzindole partially inhibited the effects of melatonin on cell viability. Melatonin at 2500 μm significantly reduced cAMP levels, and this effect was partially blocked by luzindole. Both melatonin concentrations increased the expression of phosphorylated p38, ERK, and JNK. ERK activation was completely abolished in the presence of luzindole. NQO2 but not RORα mRNA level significantly increased in luzindole-treated cells. Results obtained provide evidence that the melatonin effects on cell viability and proliferation in HepG2 cells are partially mediated through the MT1 membrane receptor, which seems to be related also with melatonin modulation of cAMP and ERK activation. This study also highlights a possible interplay between MT1 and NQO2 melatonin receptors in liver cancer cells.
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Affiliation(s)
- Sara Carbajo-Pescador
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas and Institute of Biomedicine, University of León, León, Spain
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49
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Dupré SM, Dardente H, Birnie MJ, Loudon ASI, Lincoln GA, Hazlerigg DG. Evidence for RGS4 modulation of melatonin and thyrotrophin signalling pathways in the pars tuberalis. J Neuroendocrinol 2011; 23:725-32. [PMID: 21623959 DOI: 10.1111/j.1365-2826.2011.02168.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In mammals, the pineal hormone melatonin is secreted nocturnally and acts in the pars tuberalis (PT) of the anterior pituitary to control seasonal neuroendocrine function. Melatonin signals through the type 1 Gi-protein coupled melatonin receptor (MT1), inhibiting adenylate cyclase (AC) activity and thereby reducing intracellular concentrations of the second messenger, cAMP. Because melatonin action ceases by the end of the night, this allows a daily rise in cAMP levels, which plays a key part in the photoperiodic response mechanism in the PT. In addition, melatonin receptor desensitisation and sensitisation of AC by melatonin itself appear to fine-tune this process. Opposing the actions of melatonin, thyroid-stimulating hormone (TSH), produced by PT cells, signals through its cognate Gs-protein coupled receptor (TSH-R), leading to increased cAMP production. This effect may contribute to increased TSH production by the PT during spring and summer, and is of considerable interest because TSH plays a pivotal role in seasonal neuroendocrine function. Because cAMP stands at the crossroads between melatonin and TSH signalling pathways, any protein modulating cAMP production has the potential to impact on photoperiodic readout. In the present study, we show that the regulator of G-protein signalling RGS4 is a melatonin-responsive gene, whose expression in the PT increases some 2.5-fold after melatonin treatment. Correspondingly, RGS4 expression is acutely sensitive to changing day length. In sheep acclimated to short days (SP, 8 h light/day), RGS4 expression increases sharply following dark onset, peaking in the middle of the night before declining to basal levels by dawn. Extending the day length to 16 h (LP) by an acute 8-h delay in lights off causes a corresponding delay in the evening rise of RGS4 expression, and the return to basal levels is delayed some 4 h into the next morning. To test the hypothesis that RGS4 expression modulates interactions between melatonin- and TSH-dependent cAMP signalling pathways, we used transient transfections of MT1, TSH-R and RGS4 in COS7 cells along with a cAMP-response element luciferase reporter (CRE-luc). RGS4 attenuated MT1-mediated inhibition of TSH-stimulated CRE-luc activation. We propose that RGS4 contributes to photoperiodic sensitivity in the morning induction of cAMP-dependent gene expression in the PT.
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Affiliation(s)
- S M Dupré
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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50
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Maurice P, Kamal M, Jockers R. Asymmetry of GPCR oligomers supports their functional relevance. Trends Pharmacol Sci 2011; 32:514-20. [PMID: 21715028 DOI: 10.1016/j.tips.2011.05.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/19/2011] [Accepted: 05/20/2011] [Indexed: 01/29/2023]
Abstract
G protein-coupled receptors (GPCRs) can exist as dimers or as larger oligomeric clusters that enable intercommunication between different receptor protomers within the same complex. This phenomenon is observed at three distinct levels: (i) at the level of ligand binding where the activation of one protomer can allosterically inhibit or facilitate ligand binding to the second protomer; (ii) at the level of ligand-induced conformational switches, which occur between transmembrane domains of the two protomers; and (iii) within GPCR-associated protein complexes, either directly at the level of GPCR-interacting proteins or at further downstream levels of the complex. Intercommunication at these different levels introduces asymmetry within GPCR dimers wherein each protomer fulfills its specific task. In this review, we discuss how the asymmetric behavior of GPCRs highlights the advantage of oligomeric receptor organization and supports the functional relevance of GPCR dimerization.
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Affiliation(s)
- Pascal Maurice
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France
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