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Lei S, Meng Q, Liu Y, Liu Q, Dai A, Cai X, Wang MW, Zhou Q, Zhou H, Yang D. Distinct roles of the extracellular surface residues of glucagon-like peptide-1 receptor in β-arrestin 1/2 signaling. Eur J Pharmacol 2024; 968:176419. [PMID: 38360293 DOI: 10.1016/j.ejphar.2024.176419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 02/06/2024] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) is a prime drug target for type 2 diabetes and obesity. The ligand initiated GLP-1R interaction with G protein has been well studied, but not with β-arrestin 1/2. Therefore, bioluminescence resonance energy transfer (BRET), mutagenesis and an operational model were used to evaluate the roles of 85 extracellular surface residues on GLP-1R in β-arrestin 1/2 recruitment triggered by three representative GLP-1R agonists (GLP-1, exendin-4 and oxyntomodulin). Residues selectively regulated β-arrestin 1/2 recruitment for diverse ligands, and β-arrestin isoforms were identified. Mutation of residues K130-S136, L142 and Y145 on the transmembrane helix 1 (TM1)-extracellular domain (ECD) linker decreased β-arrestin 1 recruitment but increased β-arrestin 2 recruitment. Other extracellular loop (ECL) mutations, including P137A, Q211A, D222A and M303A selectively affected β-arrestin 1 recruitment while D215A, L217A, Q221A, S223A, Y289A, S301A, F381A and I382A involved more in β-arrestin 2 recruitment for the ligands. Oxyntomodulin engaged more broadly with GLP-1R extracellular surface to drive β-arrestin 1/2 recruitment than GLP-1 and exendin-4; I147, W214 and L218 involved in β-arrestin 1 recruitment, while L141, D215, L218, D293 and F381 in β-arrestin 2 recruitment for oxyntomodulin particularly. Additionally, the non-conserved residues on β-arrestin 1/2 C-domains contributed to interaction with GLP-1R. Further proteomic profiling of GLP-1R stably expressed cell line upon ligand stimulation with or without β-arrestin 1/2 overexpression demonstrated both commonly and biasedly regulated proteins and pathways associated with cognate ligands and β-arrestins. Our study offers valuable information about ligand induced β-arrestin recruitment mediated by GLP-1R and consequent intracellular signaling events.
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Affiliation(s)
- Saifei Lei
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
| | - Qian Meng
- State Key Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yanyun Liu
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Qiaofeng Liu
- School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Antao Dai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Xiaoqing Cai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China; Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China; Department of Chemistry, School of Science, The University of Tokyo, Tokyo, 113-0033, Japan; School of Pharmacy, Hainan Medical University, Haikou, 570228, China
| | - Qingtong Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China; Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China.
| | - Hu Zhou
- State Key Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
| | - Dehua Yang
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China; State Key Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China; School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China.
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Xu J, Pittenger C. The histamine H3 receptor modulates dopamine D2 receptor-dependent signaling pathways and mouse behaviors. J Biol Chem 2023; 299:104583. [PMID: 36871761 PMCID: PMC10139999 DOI: 10.1016/j.jbc.2023.104583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The histamine H3 receptor (H3R) is highly enriched in the spiny projection neurons (SPNs) of the striatum, in both the D1 receptor (D1R)-expressing and D2 receptor (D2R)-expressing populations. A crossantagonistic interaction between H3R and D1R has been demonstrated in mice, both at the behavioral level and at the biochemical level. Although interactive behavioral effects have been described upon coactivation of H3R and D2R, the molecular mechanisms underlying this interaction are poorly understood. Here, we show that activation of H3R with the selective agonist R-(-)-α-methylhistamine dihydrobromide mitigates D2R agonist-induced locomotor activity and stereotypic behavior. Using biochemical approaches and the proximity ligation assay, we demonstrated the existence of an H3R-D2R complex in the mouse striatum. In addition, we examined consequences of simultaneous H3R-D2R agonism on the phosphorylation levels of several signaling molecules using immunohistochemistry. H3R agonist treatment modulated Akt (serine/threonine PKB)-glycogen synthase kinase 3 beta signaling in response to D2R activation via a β-arrestin 2-dependent mechanism in D2R-SPNs but not in D1R-SPNs. Phosphorylation of mitogen- and stress-activated protein kinase 1 and rpS6 (ribosomal protein S6) was largely unchanged under these conditions. As Akt-glycogen synthase kinase 3 beta signaling has been implicated in several neuropsychiatric disorders, this work may help clarify the role of H3R in modulating D2R function, leading to a better understanding of pathophysiology involving the interaction between histamine and dopamine systems.
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Affiliation(s)
- Jian Xu
- Department of Psychiatry, Yale University. ,
| | - Christopher Pittenger
- Department of Psychiatry, Yale University; Department of Psychology, Yale University; Department of Child Study Center, Yale University; Department of Interdepartmental Neuroscience Program, Yale University; Department of Wu-Tsai Institute, Yale University; Department of Center for Brain and Mind Health, Yale University.
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Burström V, Ågren R, Betari N, Valle-León M, Garro-Martínez E, Ciruela F, Sahlholm K. Dopamine-induced arrestin recruitment and desensitization of the dopamine D4 receptor is regulated by G protein-coupled receptor kinase-2. Front Pharmacol 2023; 14:1087171. [PMID: 36778010 PMCID: PMC9911804 DOI: 10.3389/fphar.2023.1087171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/18/2023] [Indexed: 01/28/2023] Open
Abstract
The dopamine D4 receptor (D4R) is expressed in the retina, prefrontal cortex, and autonomic nervous system and has been implicated in attention deficit hyperactivity disorder (ADHD), substance use disorders, and erectile dysfunction. D4R has also been investigated as a target for antipsychotics due to its high affinity for clozapine. As opposed to the closely related dopamine D2 receptor (D2R), dopamine-induced arrestin recruitment and desensitization at the D4R have not been studied in detail. Indeed, some earlier investigations could not detect arrestin recruitment and desensitization of this receptor upon its activation by agonist. Here, we used a novel nanoluciferase complementation assay to study dopamine-induced recruitment of β-arrestin2 (βarr2; also known as arrestin3) and G protein-coupled receptor kinase-2 (GRK2) to the D4R in HEK293T cells. We also studied desensitization of D4R-evoked G protein-coupled inward rectifier potassium (GIRK; also known as Kir3) current responses in Xenopus oocytes. Furthermore, the effect of coexpression of GRK2 on βarr2 recruitment and GIRK response desensitization was examined. The results suggest that coexpression of GRK2 enhanced the potency of dopamine to induce βarr2 recruitment to the D4R and accelerated the rate of desensitization of D4R-evoked GIRK responses. The present study reveals new details about the regulation of arrestin recruitment to the D4R and thus increases our understanding of the signaling and desensitization of this receptor.
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Affiliation(s)
- Viktor Burström
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Richard Ågren
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Nibal Betari
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Marta Valle-León
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, Barcelona, Spain
| | - Emilio Garro-Martínez
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, Barcelona, Spain
| | - Kristoffer Sahlholm
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden,Department of Neuroscience, Karolinska Institutet, Solna, Sweden,Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, Barcelona, Spain,*Correspondence: Kristoffer Sahlholm,
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Kawahata I, Fukunaga K. Endocytosis of dopamine receptor: Signaling in brain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:99-111. [PMID: 36813367 DOI: 10.1016/bs.pmbts.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
This chapter describes the physiological significance of dopamine receptor endocytosis and the consequence of the receptor signaling. Endocytosis of dopamine receptors is regulated by many components such as clathrin, β-arrestin, caveolin, and Rab family proteins. The dopamine receptors escape from lysosomal digestion, and their recycling occurs rapidly, reinforcing the dopaminergic signal transduction. In addition, the pathological impact of the receptors interacting with specific proteins has been the focus of much attention. Based on this background, this chapter provides an in-depth understanding of the mechanisms of molecules interacting with dopamine receptors and discusses the potential pharmacotherapeutic targets for α-synucleinopathies and neuropsychiatric disorders.
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Affiliation(s)
- Ichiro Kawahata
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
| | - Kohji Fukunaga
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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Khalid E, Chang JP. Receptor-proximal effectors mediating GnRH actions in the goldfish pituitary: Involvement of G protein subunits and GRKs. Gen Comp Endocrinol 2022; 319:113991. [PMID: 35157923 DOI: 10.1016/j.ygcen.2022.113991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/01/2022] [Accepted: 02/09/2022] [Indexed: 11/21/2022]
Abstract
In goldfish (Carassius auratus), two endogenous isoforms of gonadotropin-releasing hormone (GnRH) stimulate luteinizing hormone (LH) and growth hormone (GH) secretion. These isoforms, GnRH2 and GnRH3, act on a shared population of cell-surface GnRH receptors (GnRHRs) expressed on both gonadotrophs and somatotrophs, and can signal through unique, yet partially overlapping, suites of intracellular effectors, in a phenomenon known as functional selectivity or biased signalling. In this study, G-protein alpha (Gα) subunits were targeted with two inhibitors, YM-254890 and BIM-46187, to ascertain the contribution of specific G-protein subunits in GnRH signalling. Results with the Gαq/11-specific inhibitor YM-254890 on primary cultures of goldfish pituitary cells revealed the use of these subunits in GnRH control of both LH and GH release, as well as GnRH-induced elevations in phospho-ERK levels. Results with the pan-Gα inhibitor BIM-46187 matched those using YM-254890 in LH release but GH responses differed, indicating additional, non-Gαq/11 subunits may be involved in somatotrophs. BIM-46187 also elevated unstimulated LH and GH release suggesting that Gα subunits regulate basal hormone secretion. Furthermore, G-protein-coupled receptor kinase (GRK2/3) inhibition reduced LH responses to GnRH2 and GnRH3, and selectively enhanced GnRH2-stimulated GH release, indicating differential use of GRK2/3 in GnRH actions on gonadotrophs and somatotrophs. These findings in a primary untransformed system provide the first direct evidence to establish Gαq/11 as an obligate driver of GnRH signalling in goldfish pituitary cells, and additionally describe the differential agonist- and cell type-selective involvement of GRK2/3 in this system.
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Affiliation(s)
- Enezi Khalid
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G2E9, Canada
| | - John P Chang
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G2E9, Canada.
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Ågren R, Sahlholm K. G protein-coupled receptor kinase-2 confers isoform-specific calcium sensitivity to dopamine D 2 receptor desensitization. FASEB J 2021; 35:e22013. [PMID: 34699610 DOI: 10.1096/fj.202100704rr] [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: 04/26/2021] [Revised: 10/04/2021] [Accepted: 10/11/2021] [Indexed: 11/11/2022]
Abstract
The dopamine D2 receptor (D2 R) functions as an autoreceptor on dopaminergic cell bodies and terminals and as a postsynaptic receptor on a variety of neurons in the central nervous system. As a result of alternative splicing, the D2 R is expressed as two isoforms: long (D2L R) and short (D2S R) differing by a stretch of 29 residues in the third intracellular loop, with D2S R being the predominant presynaptic isoform. Recent reports described a Ca2+ sensitivity of the desensitization time course of potassium currents elicited via D2S R, but not via D2L R, when either isoform was selectively expressed in dopaminergic neurons. Here, we aimed to study the mechanism behind this subtype-specific Ca2+ sensitivity. Thus, we measured the desensitization of potassium channel responses evoked by D2L R and D2S R using two-electrode voltage clamp in Xenopus oocytes in the absence and presence of different amounts of β-arrestin2 and G protein-coupled receptor kinase-2 (GRK2), both of which are known to play important roles in D2 R desensitization in native cells. We found that co-expression of both GRK2 and β-arrestin2 was necessary for reconstitution of the Ca2+ sensitivity of D2S R desensitization, while D2L R did not display Ca2+ sensitivity under these conditions. The effect of Ca2+ chelation by BAPTA-AM to slow the rate of D2S R desensitization was mimicked by the GRK2 inhibitor, Cmpd101, and by the kinase-inactivating GRK2 mutation, K220R, but not by the PKC inhibitor, Gö6976, nor by the calmodulin antagonist, KN-93. Thus, Ca2+ -sensitive desensitization of D2S R appears to be mediated via a GRK2 phosphorylation-dependent mechanism.
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Affiliation(s)
- Richard Ågren
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Kristoffer Sahlholm
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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Stepniewski TM, Mancini A, Ågren R, Torrens-Fontanals M, Semache M, Bouvier M, Sahlholm K, Breton B, Selent J. Mechanistic insights into dopaminergic and serotonergic neurotransmission - concerted interactions with helices 5 and 6 drive the functional outcome. Chem Sci 2021; 12:10990-11003. [PMID: 34522296 PMCID: PMC8386650 DOI: 10.1039/d1sc00749a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 06/15/2021] [Indexed: 01/14/2023] Open
Abstract
Brain functions rely on neurotransmitters that mediate communication between billions of neurons. Disruption of this communication can result in a plethora of psychiatric and neurological disorders. In this work, we combine molecular dynamics simulations, live-cell biosensor and electrophysiological assays to investigate the action of the neurotransmitter dopamine at the dopaminergic D2 receptor (D2R). The study of dopamine and closely related chemical probes reveals how neurotransmitter binding translates into the activation of distinct subsets of D2R effectors (i.e.: Gi2, GoB, Gz and β-arrestin 2). Ligand interactions with key residues in TM5 (S5.42) and TM6 (H6.55) in the D2R binding pocket yield a dopamine-like coupling signature, whereas exclusive TM5 interaction is typically linked to preferential G protein coupling (in particular GoB) over β-arrestin. Further experiments for serotonin receptors indicate that the reported molecular mechanism is shared by other monoaminergic neurotransmitter receptors. Ultimately, our study highlights how sequence variation in position 6.55 is used by nature to fine-tune β-arrestin recruitment and in turn receptor signaling and internalization of neurotransmitter receptors.
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Affiliation(s)
- Tomasz Maciej Stepniewski
- Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM) - Pompeu Fabra University (UPF) Dr Aiguader 88 Barcelona E-08003 Spain
- InterAx Biotech AG, PARK InnovAARE 5234 Villigen Switzerland
| | - Arturo Mancini
- Domain Therapeutics NA Inc 7171 Frederick-Banting Saint-Laurent (QC) H4S 1Z9 Canada
| | - Richard Ågren
- Department of Neuroscience, Karolinska Institute Stockholm Sweden
| | - Mariona Torrens-Fontanals
- Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM) - Pompeu Fabra University (UPF) Dr Aiguader 88 Barcelona E-08003 Spain
| | - Meriem Semache
- Domain Therapeutics NA Inc 7171 Frederick-Banting Saint-Laurent (QC) H4S 1Z9 Canada
| | - Michel Bouvier
- Department of Biochemistry and Molecular Medicine, Université de Montréal Montreal QC H3C 3J7 Canada
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal Montréal Québec H3T 1J4 Canada
| | - Kristoffer Sahlholm
- Department of Neuroscience, Karolinska Institute Stockholm Sweden
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University 90187 Umeå Sweden
| | - Billy Breton
- Domain Therapeutics NA Inc 7171 Frederick-Banting Saint-Laurent (QC) H4S 1Z9 Canada
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal Montréal Québec H3T 1J4 Canada
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM) - Pompeu Fabra University (UPF) Dr Aiguader 88 Barcelona E-08003 Spain
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Gurevich EV, Gurevich VV. GRKs as Modulators of Neurotransmitter Receptors. Cells 2020; 10:cells10010052. [PMID: 33396400 PMCID: PMC7823573 DOI: 10.3390/cells10010052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 01/08/2023] Open
Abstract
Many receptors for neurotransmitters, such as dopamine, norepinephrine, acetylcholine, and neuropeptides, belong to the superfamily of G protein-coupled receptors (GPCRs). A general model posits that GPCRs undergo two-step homologous desensitization: the active receptor is phosphorylated by kinases of the G protein-coupled receptor kinase (GRK) family, whereupon arrestin proteins specifically bind active phosphorylated receptors, shutting down G protein-mediated signaling, facilitating receptor internalization, and initiating distinct signaling pathways via arrestin-based scaffolding. Here, we review the mechanisms of GRK-dependent regulation of neurotransmitter receptors, focusing on the diverse modes of GRK-mediated phosphorylation of receptor subtypes. The immediate signaling consequences of GRK-mediated receptor phosphorylation, such as arrestin recruitment, desensitization, and internalization/resensitization, are equally diverse, depending not only on the receptor subtype but also on phosphorylation by GRKs of select receptor residues. We discuss the signaling outcome as well as the biological and behavioral consequences of the GRK-dependent phosphorylation of neurotransmitter receptors where known.
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AMP-activated protein kinase slows D2 dopamine autoreceptor desensitization in substantia nigra neurons. Neuropharmacology 2019; 158:107705. [PMID: 31301335 DOI: 10.1016/j.neuropharm.2019.107705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/14/2022]
Abstract
Dopamine neurons in the substantia nigra zona compacta (SNC) are well known to express D2 receptors. When dopamine is released from somatodendritic sites, activation of D2 autoreceptors suppresses dopamine neuronal activity through activation of G protein-coupled K+ channels. AMP-activated protein kinase (AMPK) is a master enzyme that acts in somatic tissues to suppress energy expenditure and encourage energy production. We hypothesize that AMPK may also conserve energy in central neurons by reducing desensitization of D2 autoreceptors. We used whole-cell patch-clamp recordings to study the effects of AMPK activators and inhibitors on D2 autoreceptor-mediated current in SNC neurons in midbrain slices from rat pups (11-23 days post-natal). Slices were superfused with 100 μM dopamine or 30 μM quinpirole for 25 min, which evoked outward currents that decayed slowly over time. Although the AMPK activators A769662 and ZLN024 significantly slowed rundown of dopamine-evoked current, slowing of quinpirole-evoked current required the presence of a D1-like agonist (SKF38393). Moreover, the D1-like agonist also slowed the rundown of quinpirole-induced current even in the absence of an AMPK activator. Pharmacological antagonist experiments showed that the D1-like agonist effect required activation of either protein kinase A (PKA) or exchange protein directly activated by cAMP 2 (Epac2) pathways. In contrast, the effect of AMPK on rundown of current evoked by quinpirole plus SKF38393 required PKA but not Epac2. We conclude that AMPK slows D2 autoreceptor desensitization by augmenting the effect of D1-like receptors.
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Ulloa-Aguirre A, Zariñán T, Gutiérrez-Sagal R, Dias JA. Intracellular Trafficking of Gonadotropin Receptors in Health and Disease. Handb Exp Pharmacol 2018; 245:1-39. [PMID: 29063275 DOI: 10.1007/164_2017_49] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gonadotropin receptors belong to the highly conserved subfamily of the G protein-coupled receptor (GPCR) superfamily, the so-called Rhodopsin-like family (class A), which is the largest class of GPCRs and currently a major drug target. Both the follicle-stimulating hormone receptor (FSHR) and the luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) are mainly located in the gonads where they play key functions associated to essential reproductive functions. As any other protein, gonadotropin receptors must be properly folded into a mature tertiary conformation compatible with quaternary assembly and endoplasmic reticulum export to the cell surface plasma membrane. Several primary and secondary structural features, including presence of particular amino acid residues and short motifs and in addition, posttranslational modifications, regulate intracellular trafficking of gonadotropin receptors to the plasma membrane as well as internalization and recycling of the receptor back to the cell surface after activation by agonist. Inactivating mutations of gonadotropin receptors may derive from receptor misfolding and lead to absent or reduced plasma membrane expression of the altered receptor, thereby manifesting an array of phenotypical abnormalities mostly characterized by reproductive failure and/or abnormal or absence of development of secondary sex characteristics. In this chapter we review the structural requirements necessary for intracellular trafficking of the gonadotropin receptors, and describe how mutations in these receptors may lead to receptor misfolding and disease in humans.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico.
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - James A Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
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Abstract
Dendritic release of dopamine activates dopamine D2 autoreceptors, which are inhibitory G protein-coupled receptors (GPCRs), to decrease the excitability of dopamine neurons. This study used tagged D2 receptors to identify the localization and distribution of these receptors in living midbrain dopamine neurons. GFP-tagged D2 receptors were found to be unevenly clustered on the soma and dendrites of dopamine neurons within the substantia nigra pars compacta (SNc). Physiological signaling and desensitization of the tagged receptors were not different from wild type receptors. Unexpectedly, upon desensitization the tagged D2 receptors were not internalized. When tagged D2 receptors were expressed in locus coeruleus neurons, a desensitizing protocol induced significant internalization. Likewise, when tagged µ-opioid receptors were expressed in dopamine neurons they too were internalized. The distribution and lack of agonist-induced internalization of D2 receptors on dopamine neurons indicate a purposefully regulated localization of these receptors.
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Emery MA, Bates MLS, Wellman PJ, Eitan S. Differential Effects of Oxycodone, Hydrocodone, and Morphine on Activation Levels of Signaling Molecules. PAIN MEDICINE 2015; 17:908-914. [PMID: 26349634 DOI: 10.1111/pme.12918] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Opioids alter the responses of D2-like dopamine receptors (D2DRs), known to be involved in the pathology of addiction and other mental illnesses. Importantly, our recent results demonstrated that various opioids differentially modulate the behavioral responses of D2DRs. OBJECTIVE To examine the effect of various opioids on striatal activation levels of Akt and ERK1/2, as well as the signaling responses of D2DRs following opioid exposure. METHODS Mice were pre-treated with 20 mg/kg morphine, hydrocodone, oxycodone, or saline for 6 days. Twenty-four hours later, mice were injected with vehicle or a D2/D3 receptor agonist, quinpirole. Thirty minutes later, dorsal striatum was collected and analyzed using Western blot. RESULTS In morphine-pretreated animals, baseline Akt activation level was unchanged, but was reduced in response to quinpirole. In contrast, baseline Akt activation levels were reduced in mice pretreated with hydrocodone and oxycodone, but were unchanged in response to quinpirole. In mice pretreated with all opioids, baseline ERK2 activation levels were unchanged and increased in response to quinpirole. However, quinpirole-induced ERK2 activation was significantly higher than drug naïve animals only in the morphine-pretreated mice. CONCLUSIONS Various opioids differentially modulate the baseline activation levels of signaling molecules, which in turn results in ligand-selective effects on the responses to a D2/D3 dopamine receptor agonist. This demonstrates a complex interplay between opioid receptors and D2DRs, and supports the notion that various opioids carry differential risks to the dopamine reward system. This information should be considered when prescribing opioid pain medication, to balance effectiveness with minimal risk.
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Affiliation(s)
- Michael A Emery
- Department of Psychology, Behavioral and Cellular Neuroscience Program, and the Interdisciplinary Program in Neuroscience, Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, 4235 TAMU, College Station, TX, USA
| | - M L Shawn Bates
- Department of Psychology, Behavioral and Cellular Neuroscience Program, and the Interdisciplinary Program in Neuroscience, Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, 4235 TAMU, College Station, TX, USA
| | - Paul J Wellman
- Department of Psychology, Behavioral and Cellular Neuroscience Program, and the Interdisciplinary Program in Neuroscience, Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, 4235 TAMU, College Station, TX, USA
| | - Shoshana Eitan
- Department of Psychology, Behavioral and Cellular Neuroscience Program, and the Interdisciplinary Program in Neuroscience, Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, 4235 TAMU, College Station, TX, USA
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13
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Elucidation of G-protein and β-arrestin functional selectivity at the dopamine D2 receptor. Proc Natl Acad Sci U S A 2015; 112:7097-102. [PMID: 25964346 DOI: 10.1073/pnas.1502742112] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The neuromodulator dopamine signals through the dopamine D2 receptor (D2R) to modulate central nervous system functions through diverse signal transduction pathways. D2R is a prominent target for drug treatments in disorders where dopamine function is aberrant, such as schizophrenia. D2R signals through distinct G-protein and β-arrestin pathways, and drugs that are functionally selective for these pathways could have improved therapeutic potential. How D2R signals through the two pathways is still not well defined, and efforts to elucidate these pathways have been hampered by the lack of adequate tools for assessing the contribution of each pathway independently. To address this, Evolutionary Trace was used to produce D2R mutants with strongly biased signal transduction for either the G-protein or β-arrestin interactions. These mutants were used to resolve the role of G proteins and β-arrestins in D2R signaling assays. The results show that D2R interactions with the two downstream effectors are dissociable and that G-protein signaling accounts for D2R canonical MAP kinase signaling cascade activation, whereas β-arrestin only activates elements of this cascade under certain conditions. Nevertheless, when expressed in mice in GABAergic medium spiny neurons of the striatum, the β-arrestin-biased D2R caused a significant potentiation of amphetamine-induced locomotion, whereas the G protein-biased D2R had minimal effects. The mutant receptors generated here provide a molecular tool set that should enable a better definition of the individual roles of G-protein and β-arrestin signaling pathways in D2R pharmacology, neurobiology, and associated pathologies.
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Allouche S, Noble F, Marie N. Opioid receptor desensitization: mechanisms and its link to tolerance. Front Pharmacol 2014; 5:280. [PMID: 25566076 PMCID: PMC4270172 DOI: 10.3389/fphar.2014.00280] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/02/2014] [Indexed: 02/04/2023] Open
Abstract
Opioid receptors (OR) are part of the class A of G-protein coupled receptors and the target of the opiates, the most powerful analgesic molecules used in clinic. During a protracted use, a tolerance to analgesic effect develops resulting in a reduction of the effectiveness. So understanding mechanisms of tolerance is a great challenge and may help to find new strategies to tackle this side effect. This review will summarize receptor-related mechanisms that could underlie tolerance especially receptor desensitization. We will focus on the latest data obtained on molecular mechanisms involved in opioid receptor desensitization: phosphorylation, receptor uncoupling, internalization, and post-endocytic fate of the receptor.
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Affiliation(s)
- Stéphane Allouche
- Laboratoire de Signalisation, Électrophysiologie et Imagerie des Lésions D'ischémie-Reperfusion Myocardique, Université de Caen, UPRES EA 4650, IFR 146 ICORE Caen, France
| | - Florence Noble
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
| | - Nicolas Marie
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
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15
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Abstract
This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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16
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Octeau JC, Schrader JM, Masuho I, Sharma M, Aiudi C, Chen CK, Kovoor A, Celver J. G protein beta 5 is targeted to D2-dopamine receptor-containing biochemical compartments and blocks dopamine-dependent receptor internalization. PLoS One 2014; 9:e105791. [PMID: 25162404 PMCID: PMC4146516 DOI: 10.1371/journal.pone.0105791] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/23/2014] [Indexed: 11/18/2022] Open
Abstract
G beta 5 (Gbeta5, Gβ5) is a unique G protein β subunit that is thought to be expressed as an obligate heterodimer with R7 regulator of G protein signaling (RGS) proteins instead of with G gamma (Gγ) subunits. We found that D2-dopamine receptor (D2R) coexpression enhances the expression of Gβ5, but not that of the G beta 1 (Gβ1) subunit, in HEK293 cells, and that the enhancement of expression occurs through a stabilization of Gβ5 protein. We had previously demonstrated that the vast majority of D2R either expressed endogenously in the brain or exogenously in cell lines segregates into detergent-resistant biochemical fractions. We report that when expressed alone in HEK293 cells, Gβ5 is highly soluble, but is retargeted to the detergent-resistant fraction after D2R coexpression. Furthermore, an in-cell biotin transfer proximity assay indicated that D2R and Gβ5 segregating into the detergent-resistant fraction specifically interacted in intact living cell membranes. Dopamine-induced D2R internalization was blocked by coexpression of Gβ5, but not Gβ1. However, the same Gβ5 coexpression levels had no effect on agonist-induced internalization of the mu opioid receptor (MOR), cell surface D2R levels, dopamine-mediated recruitment of β-arrestin to D2R, the amplitude of D2R-G protein coupling, or the deactivation kinetics of D2R-activated G protein signals. The latter data suggest that the interactions between D2R and Gβ5 are not mediated by endogenously expressed R7 RGS proteins.
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Affiliation(s)
- J. Christopher Octeau
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Joseph M. Schrader
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Meenakshi Sharma
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Christopher Aiudi
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Ching-Kang Chen
- Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Abraham Kovoor
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
- * E-mail: (AK); (JC)
| | - Jeremy Celver
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
- * E-mail: (AK); (JC)
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