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α-Synuclein Induced the Occurrence of RBD via Interaction with OX1R and Modulated Its Degradation. Neuromolecular Med 2023:10.1007/s12017-023-08735-4. [PMID: 36689149 DOI: 10.1007/s12017-023-08735-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/12/2023] [Indexed: 01/24/2023]
Abstract
Rapid eye movement (REM) sleep behavior disorder (RBD) is a powerful early sign of Parkinson's disease (PD), but the pathogenetic mechanism involved in RBD remains largely unexplored. α-Synuclein has been verified to form Lewy bodies in the orexin neurons, whose activity and function rely on the orexin 1 receptor (OX1R). Dysfunction of the OX1R may induce the occurrence of RBD. Here, we determined the role of the interaction between α-Synuclein and OX1R in the pathogenesis of RBD, in vitro and in vivo. We found that injection of α-Synuclein into the lateral hypothalamus area (LHA) damaged orexin neurons and induced the RBD-like sleep pattern, to further damage dopaminergic neurons and result in locomotor dysfunction in mice. α-Synuclein interacted with OX1R, promoting the degradation of OX1R through proteasomal and lysosomal pathways. In addition, overexpression of α-Synuclein downregulated OX1R-mediated signaling, subsequently leading to orexin neuron damage. We conclude that α-Synuclein induced the occurrence of RBD via interaction with OX1R and modulated its degradation. These findings provide evidence for a novel mechanism by which the association of α-Synuclein with OX1R was attributed to α-Synuclein-induced orexin neuron damage, which may be a new molecular target for an effective therapeutic strategy for RBD pathology.
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Lessel U, Ferrara M, Heine N, Marelli C, Carrettoni L, Pfau R, Schmidt E, Riether D. Identification of Highly Selective Orexin 1 Receptor Antagonists Driven by Structure-Based Design. J Chem Inf Model 2021; 61:5893-5905. [PMID: 34817173 DOI: 10.1021/acs.jcim.1c01055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OX1 receptor antagonists are of interest to treat, for example, substance abuse disorders, personality disorders, eating disorders, or anxiety-related disorders. However, known dual OX1/OX2 receptor antagonists are not suitable due to their sleep-inducing effects; therefore, we were interested in identifying a highly OX1 selective antagonist with a sufficient window to OX2-mediated effects. Herein, we describe the design of highly selective OX1 receptor antagonists driven by the X-ray structure of OX1 with suvorexant, a dual OX1/OX2 receptor antagonist. Moderately selective OX1 antagonists comprising a [2.2.1]-bicyclic scaffold served as our starting point. Based on our binding mode hypothesis, we postulated which part of the scaffold points toward one of the regions where the two binding pockets differ. Structural changes in this part resulted in a modified core with higher inherent selectivity compared to the [2.2.1]-bicyclic template. The structure-based design, synthesis, and hit-to-lead evaluation of this novel OX1 receptor-selective scaffold are discussed herein.
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Affiliation(s)
- Uta Lessel
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
| | - Marco Ferrara
- Boehringer Ingelheim Research Italia S.a.s. di BI IT S.r.l., Via Giovanni Lorenzini 8, 20139 Milano, MI, Italy
| | - Niklas Heine
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
| | - Chiara Marelli
- Boehringer Ingelheim Research Italia S.a.s. di BI IT S.r.l., Via Giovanni Lorenzini 8, 20139 Milano, MI, Italy
| | - Laura Carrettoni
- Boehringer Ingelheim Research Italia S.a.s. di BI IT S.r.l., Via Giovanni Lorenzini 8, 20139 Milano, MI, Italy
| | - Roland Pfau
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
| | - Esther Schmidt
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
| | - Doris Riether
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
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Thompson MD, Sakurai T, Rainero I, Maj MC, Kukkonen JP. Orexin Receptor Multimerization versus Functional Interactions: Neuropharmacological Implications for Opioid and Cannabinoid Signalling and Pharmacogenetics. Pharmaceuticals (Basel) 2017; 10:ph10040079. [PMID: 28991183 PMCID: PMC5748636 DOI: 10.3390/ph10040079] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/29/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
Orexins/hypocretins are neuropeptides formed by proteolytic cleavage of a precursor peptide, which are produced by neurons found in the lateral hypothalamus. The G protein-coupled receptors (GPCRs) for these ligands, the OX₁ and OX₂ orexin receptors, are more widely expressed throughout the central nervous system. The orexin/hypocretin system has been implicated in many pathways, and its dysregulation is under investigation in a number of diseases. Disorders in which orexinergic mechanisms are being investigated include narcolepsy, idiopathic sleep disorders, cluster headache and migraine. Human narcolepsy has been associated with orexin deficiency; however, it has only rarely been attributed to mutations in the gene encoding the precursor peptide. While gene variations within the canine OX₂ gene hcrtr2 have been directly linked with narcolepsy, the majority of human orexin receptor variants are weakly associated with diseases (the idiopathic sleep disorders, cluster headache and polydipsia-hyponatremia in schizophrenia) or are of potential pharmacogenetic significance. Evidence for functional interactions and/or heterodimerization between wild-type and variant orexin receptors and opioid and cannabinoid receptors is discussed in the context of its relevance to depression and epilepsy.
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Affiliation(s)
- Miles D Thompson
- Department of Pediatrics, University of California, San Diego 92093, CA, USA.
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa 920-8620, Japan.
| | - Innocenzo Rainero
- Department of Neuroscience, University of Turin, Torino 10124, Italy.
| | - Mary C Maj
- Department of Biochemistry, School of Medicine, Saint George's University, Saint George's 11739, Grenada.
| | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki 11739, Finland.
- Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki 00100, Finland.
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Reiter E, Ayoub MA, Pellissier LP, Landomiel F, Musnier A, Tréfier A, Gandia J, De Pascali F, Tahir S, Yvinec R, Bruneau G, Poupon A, Crépieux P. β-arrestin signalling and bias in hormone-responsive GPCRs. Mol Cell Endocrinol 2017; 449:28-41. [PMID: 28174117 DOI: 10.1016/j.mce.2017.01.052] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 12/14/2022]
Abstract
G protein-coupled receptors (GPCRs) play crucial roles in the ability of target organs to respond to hormonal cues. GPCRs' activation mechanisms have long been considered as a two-state process connecting the agonist-bound receptor to heterotrimeric G proteins. This view is now challenged as mounting evidence point to GPCRs being connected to large arrays of transduction mechanisms involving heterotrimeric G proteins as well as other players. Amongst the G protein-independent transduction mechanisms, those elicited by β-arrestins upon their recruitment to the active receptors are by far the best characterized and apply to most GPCRs. These concepts, in conjunction with remarkable advances made in the field of GPCR structural biology and biophysics, have supported the notion of ligand-selective signalling also known as pharmacological bias. Interestingly, recent reports have opened intriguing prospects to the way β-arrestins control GPCR-mediated signalling in space and time within the cells. In the present paper, we review the existing evidence linking endocrine-related GPCRs to β-arrestin recruitement, signalling, pathophysiological implications and selective activation by biased ligands and/or receptor modifications. Emerging concepts surrounding β-arrestin-mediated transduction are discussed in the light of the peculiarities of endocrine systems.
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Affiliation(s)
- Eric Reiter
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France.
| | - Mohammed Akli Ayoub
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France; LE STUDIUM(®) Loire Valley Institute for Advanced Studies, 45000, Orléans, France; Biology Department, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | | | - Flavie Landomiel
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Astrid Musnier
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Aurélie Tréfier
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Jorge Gandia
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | | | - Shifa Tahir
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Romain Yvinec
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Gilles Bruneau
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Anne Poupon
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
| | - Pascale Crépieux
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380, Nouzilly, France
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Yang Z, Yang F, Zhang D, Liu Z, Lin A, Liu C, Xiao P, Yu X, Sun JP. Phosphorylation of G Protein-Coupled Receptors: From the Barcode Hypothesis to the Flute Model. Mol Pharmacol 2017; 92:201-210. [DOI: 10.1124/mol.116.107839] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 02/23/2017] [Indexed: 12/21/2022] Open
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Stoddart LA, White CW, Nguyen K, Hill SJ, Pfleger KDG. Fluorescence- and bioluminescence-based approaches to study GPCR ligand binding. Br J Pharmacol 2016; 173:3028-37. [PMID: 26317175 PMCID: PMC5125978 DOI: 10.1111/bph.13316] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/01/2015] [Accepted: 08/20/2015] [Indexed: 01/15/2023] Open
Abstract
Ligand binding is a vital component of any pharmacologist's toolbox and allows the detailed investigation of how a molecule binds to its receptor. These studies enable the experimental determination of binding affinity of labelled and unlabelled compounds through kinetic, saturation (Kd ) and competition (Ki ) binding assays. Traditionally, these studies have used molecules labelled with radioisotopes; however, more recently, fluorescent ligands have been developed for this purpose. This review will briefly cover receptor ligand binding theory and then discuss the use of fluorescent ligands with some of the different technologies currently employed to examine ligand binding. Fluorescent ligands can be used for direct measurement of receptor-associated fluorescence using confocal microscopy and flow cytometry as well as in assays such as fluorescence polarization, where ligand binding is monitored by changes in the free rotation when a fluorescent ligand is bound to a receptor. Additionally, fluorescent ligands can act as donors or acceptors for fluorescence resonance energy transfer (FRET) with the development of assays based on FRET and time-resolved FRET (TR-FRET). Finally, we have recently developed a novel bioluminescence resonance energy transfer (BRET) ligand binding assay utilizing a small (19 kDa), super-bright luciferase subunit (NanoLuc) from a deep sea shrimp. In combination with fluorescent ligands, measurement of RET now provides an array of methodologies to study ligand binding. While each method has its own advantages and drawbacks, binding studies using fluorescent ligands are now a viable alternative to the use of radioligands. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- Leigh A Stoddart
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Kim Nguyen
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Stephen J Hill
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Nottingham, UK
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.
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Tiulpakov A, White CW, Abhayawardana RS, See HB, Chan AS, Seeber RM, Heng JI, Dedov I, Pavlos NJ, Pfleger KDG. Mutations of Vasopressin Receptor 2 Including Novel L312S Have Differential Effects on Trafficking. Mol Endocrinol 2016; 30:889-904. [PMID: 27355191 PMCID: PMC4965841 DOI: 10.1210/me.2016-1002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a genetic disease first described in 2 unrelated male infants with severe symptomatic hyponatremia. Despite undetectable arginine vasopressin levels, patients have inappropriately concentrated urine resulting in hyponatremia, hypoosmolality, and natriuresis. Here, we describe and functionally characterize a novel vasopressin type 2 receptor (V2R) gain-of-function mutation. An L312S substitution in the seventh transmembrane domain was identified in a boy presenting with water-induced hyponatremic seizures at the age of 5.8 years. We show that, compared with wild-type V2R, the L312S mutation results in the constitutive production of cAMP, indicative of the gain-of-function NSIAD profile. Interestingly, like the previously described F229V and I130N NSIAD-causing mutants, this appears to both occur in the absence of notable constitutive β-arrestin2 recruitment and can be reduced by the inverse agonist Tolvaptan. In addition, to understand the effect of various V2R substitutions on the full receptor "life-cycle," we have used and further developed a bioluminescence resonance energy transfer intracellular localization assay using multiple localization markers validated with confocal microscopy. This allowed us to characterize differences in the constitutive and ligand-induced localization and trafficking profiles of the novel L312S mutation as well as for previously described V2R gain-of-function mutants (NSIAD; R137C and R137L), loss-of-function mutants (nephrogenic diabetes insipidus; R137H, R181C, and M311V), and a putative silent V266A V2R polymorphism. In doing so, we describe differences in trafficking between unique V2R substitutions, even at the same amino acid position, therefore highlighting the value of full and thorough characterization of receptor function beyond simple signaling pathway analysis.
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Affiliation(s)
- Anatoly Tiulpakov
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Carl W White
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Rekhati S Abhayawardana
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Heng B See
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Audrey S Chan
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Ruth M Seeber
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Julian I Heng
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Ivan Dedov
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Nathan J Pavlos
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
| | - Kevin D G Pfleger
- Harry Perkins Institute of Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.), QEII Medical Centre; Centre for Medical Research (C.W.W., R.S.A., H.B.S., R.M.S., J.I.H., K.D.G.P.) and School of Surgery (A.S.C., N.J.P.), The University of Western Australia; and Dimerix Limited (K.D.G.P.), Nedlands, Western Australia 6009, Australia; and Department and Laboratory of Inherited Endocrine Disorders (A.T., I.D.), Endocrinology Research Centre, Moscow 117036, Russia
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Jean-Charles PY, Freedman NJ, Shenoy SK. Chapter Nine - Cellular Roles of Beta-Arrestins as Substrates and Adaptors of Ubiquitination and Deubiquitination. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:339-69. [PMID: 27378762 DOI: 10.1016/bs.pmbts.2016.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
β-Arrestin1 and β-arrestin2 are homologous adaptor proteins that are ubiquitously expressed in mammalian cells. They belong to a four-member family of arrestins that regulate the vast family of seven-transmembrane receptors that couple to heterotrimeric G proteins (7TMRs or GPCRs), and that modulate 7TMR signal transduction. β-Arrestins were originally identified in the context of signal inhibition via the 7TMRs because they competed with and thereby blocked G protein coupling to 7TMRs. Currently, in addition to their role as desensitizers of signaling, β-arrestins are appreciated as multifunctional adaptors that mediate trafficking and signal transduction of not only 7TMRs, but a growing list of additional receptors, ion channels, and nonreceptor proteins. β-Arrestins' interactions with their multifarious partners are based on their dynamic conformational states rather than particular domain-domain interactions. β-Arrestins adopt activated conformations upon 7TMR association. In addition, β-arrestins undergo various posttranslational modifications that are choreographed by activated 7TMRs, including phosphorylation, ubiquitination, acetylation, nitrosylation, and SUMOylation. Ubiquitination of β-arrestins is critical for their high-affinity interaction with 7TMRs as well as with endocytic adaptor proteins and signaling kinases. β-Arrestins also function as critical adaptors for ubiquitination and deubiquitination of various cellular proteins, and thereby affect the longevity of signal transducers and the intensity of signal transmission.
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Affiliation(s)
- P-Y Jean-Charles
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina, United States
| | - N J Freedman
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina, United States; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States
| | - S K Shenoy
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina, United States; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States.
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Jean-Charles PY, Rajiv V, Shenoy SK. Ubiquitin-Related Roles of β-Arrestins in Endocytic Trafficking and Signal Transduction. J Cell Physiol 2016; 231:2071-80. [PMID: 26790995 DOI: 10.1002/jcp.25317] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 12/25/2022]
Abstract
The non-visual arrestins, β-arrestin1, and β-arrestin2 were originally identified as proteins that bind to seven-transmembrane receptors (7TMRs, also called G protein-coupled receptors, GPCRs) and block heterotrimeric G protein activation, thus leading to desensitization of transmembrane signaling. However, as subsequent discoveries have continually demonstrated, their functionality is not constrained to desensitization. They are now recognized for their critical roles in mediating intracellular trafficking of 7TMRs, growth factor receptors, ion transporters, ion channels, nuclear receptors, and non-receptor proteins. Additionally, they function as crucial mediators of ubiquitination of 7TMRs as well as other receptors and non-receptor proteins. Recently, emerging studies suggest that a class of proteins with predicted structural features of β-arrestins regulate substrate ubiquitination in yeast and higher mammals, lending support to the idea that the adaptor role of β-arrestins in protein ubiquitination is evolutionarily conserved. β-arrestins also function as scaffolds for kinases and transduce signals from 7TMRs through pathways that do not require G protein activation. Remarkably, the endocytic and scaffolding functions of β-arrestin are intertwined with its ubiquitination status; the dynamic and site specific ubiquitination on β-arrestin plays a critical role in stabilizing β-arrestin-7TMR association and the formation of signalosomes. This review summarizes the current findings on ubiquitin-dependent regulation of 7TMRs as well as β-arrestins and the potential role of reversible ubiquitination as a "biological switch" in signal transduction. J. Cell. Physiol. 231: 2071-2080, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Vishwaesh Rajiv
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina
| | - Sudha K Shenoy
- Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina.,Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
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Abstract
Since their discovery, G protein-coupled receptors (GPCRs) constitute one of the most studied proteins leading to important discoveries and perspectives in terms of their biology and implication in physiology and pathophysiology. This is mostly linked to the remarkable advances in the development and application of the biophysical resonance energy transfer (RET)-based approaches, including bioluminescence and fluorescence resonance energy transfer (BRET and FRET, respectively). Indeed, BRET and FRET have been extensively applied to study different aspects of GPCR functioning such as their activation and regulation either statically or dynamically, in real-time and intact cells. Consequently, our view on GPCRs has considerably changed opening new challenges for the study of GPCRs in their native tissues in the aim to get more knowledge on how these receptors control the biological responses. Moreover, the technological aspect of this field of research promises further developments for robust and reliable new RET-based assays that may be compatible with high-throughput screening as well as drug discovery programs.
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Affiliation(s)
- Mohammed Akli Ayoub
- Biologie et Bioinformatique des Systèmes de Signalisation, Institut National de la Recherche Agronomique, UMR85, Unité Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Nouzilly, France; LE STUDIUM(®) Loire Valley Institute for Advanced Studies, Orléans, France.
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Johnstone EKM, Pfleger KDG. Bioluminescence Resonance Energy Transfer Approaches to Discover Bias in GPCR Signaling. Methods Mol Biol 2015; 1335:191-204. [PMID: 26260602 DOI: 10.1007/978-1-4939-2914-6_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bioluminescence resonance energy transfer (BRET) is a well-established technique for investigating G protein-coupled receptor (GPCR) pharmacology. BRET enables the monitoring of molecular proximity through the use of heterologously expressed proteins of interest and/or fluorophore-labeled ligands. Fusion to a donor luciferase enzyme or an acceptor fluorophore and subsequent detection of resonance energy transfer indicate the close proximity of the molecules of interest. As BRET is readily applied to the study of numerous GPCR signaling and regulatory paths, it is an ideal technique for investigating the pharmacology of biased ligands and receptors.
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Affiliation(s)
- Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, 6 Verdun Street, Nedlands, WA, 6009, Australia
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Abstract
Addiction is a chronic relapsing disorder which presents a significant global health burden and unmet medical need. The orexin/hypocretin system is an attractive potential therapeutic target as demonstrated by the successful clinical trials of antagonist medications like Suvorexant for insomnia. It is composed of two neuropeptides, orexin-A and orexin-B and two excitatory and promiscuous G-protein coupled receptors, OX1 and OX2. Orexins are known to have a variety of functions, most notably in regulating arousal, appetite and reward. The orexins have been shown to have a role in mediating the effects of several drugs of abuse, such as cocaine, morphine and alcohol via projections to key brain regions such as the ventral tegmental area, nucleus accumbens and prefrontal cortex. However, it has not yet been demonstrated whether the dual orexin receptor antagonists (DORAs) under development for insomnia are ideal drugs for the treatment of addiction. The question of whether to use a DORA or single orexin receptor antagonist (SORA) for the treatment of addiction is a key question that will need to be answered in order to maximize the clinical utility of orexin receptor antagonists. This review will examine the role of the orexin/hypocretin system in addiction, orexin-based pharmacotherapies under development and factors affecting the selection of one or both orexin receptors as drug targets for the treatment of addiction.
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Jaeger WC, Armstrong SP, Hill SJ, Pfleger KDG. Biophysical Detection of Diversity and Bias in GPCR Function. Front Endocrinol (Lausanne) 2014; 5:26. [PMID: 24634666 PMCID: PMC3943086 DOI: 10.3389/fendo.2014.00026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 02/19/2014] [Indexed: 12/27/2022] Open
Abstract
Guanine nucleotide binding protein (G protein)-coupled receptors (GPCRs) function in complexes with a range of molecules and proteins including ligands, G proteins, arrestins, ubiquitin, and other receptors. Elements of these complexes may interact constitutively or dynamically, dependent upon factors such as ligand binding, phosphorylation, and dephosphorylation. They may also be allosterically modulated by other proteins in a manner that changes temporally and spatially within the cell. Elucidating how these complexes function has been greatly enhanced by biophysical technologies that are able to monitor proximity and/or binding, often in real time and in live cells. These include resonance energy transfer approaches such as bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET). Furthermore, the use of fluorescent ligands has enabled novel insights into allosteric interactions between GPCRs. Consequently, biophysical approaches are helping to unlock the amazing diversity and bias in G protein-coupled receptor signaling.
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Affiliation(s)
- Werner C. Jaeger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Stephen P. Armstrong
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Stephen J. Hill
- Cell Signalling Research Group, School of Life Sciences, Queen’s Medical Centre, University of Nottingham Medical School, Nottingham, UK
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
- Dimerix Bioscience Pty Ltd, Perth, WA, Australia
- *Correspondence: Kevin D. G. Pfleger, Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, QEII Medical Centre, QQ Block, 6 Verdun Street, Nedlands, Perth, WA 6009, Australia e-mail:
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