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Millett M, Heuberger A, Martin Castosa E, Comite A, Wagner P, Hall D, Gallardo I, Chambers NE, Wagner L, Reinhardt J, Moehle MS. Neuron specific quantitation of Gα olf expression and signaling in murine brain tissue. Brain Res 2024; 1842:149105. [PMID: 38960060 DOI: 10.1016/j.brainres.2024.149105] [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: 04/12/2024] [Revised: 06/19/2024] [Accepted: 06/29/2024] [Indexed: 07/05/2024]
Abstract
The heterotrimeric G-protein α subunit, Gαolf, acts to transduce extracellular signals through G-protein coupled receptors (GPCRs) and stimulates adenylyl cyclase mediated production of the second messenger cyclic adenosine monophosphate. Numerous mutations in the GNAL gene, which encodes Gαolf, have been identified as causative for an adult-onset dystonia. These mutations disrupt GPCR signaling cascades in in vitro assays through several mechanisms, and this disrupted signaling is hypothesized to lead to dystonic motor symptoms in patients. However, the cells and circuits that mutations in GNAL corrupt are not well understood. Published patterns of Gαolf expression outside the context of the striatum are sparse, conflicting, often lack cell type specificity, and may be confounded by expression of the close GNAL homolog of GNAS. Here, we use RNAScope in-situ hybridization to quantitatively characterize Gnal mRNA expression in brain tissue from wildtype C57BL/6J adult mice. We observed widespread expression of Gnal puncta throughout the brain, suggesting Gαolf is expressed in more brain structures and neuron types than previously accounted for. We quantify transcripts at a single cell level, and use neuron type specific markers to further classify and understand patterns of GNAL expression. Our data suggests that brain regions classically associated with motor control, initiation, and regulation show the highest expression of GNAL, with Purkinje Cells of the cerebellum showing the highest expression of any neuron type examined. Subsequent conditional Gnal knockout in Purkinje cells led to markedly decreased intracellular cAMP levels and downstream cAMP-dependent enzyme activation. Our work provides a detailed characterization of Gnal expression throughout the brain and the biochemical consequences of loss of Gαolf signaling in vivo in neurons that highly express Gnal.
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Affiliation(s)
- Michael Millett
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Anika Heuberger
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Elisabeth Martin Castosa
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Allison Comite
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Preston Wagner
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Dominic Hall
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Ignacio Gallardo
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Nicole E Chambers
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Lloyd Wagner
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Jessica Reinhardt
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
| | - Mark S Moehle
- Department of Pharmacology & Therapeutics and Center for Translational Research in Neurodegeneration, University of Florida College of Medicine, Gainesville, FL, 32610, United States.
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2
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Pelletier OB, Brunori G, Wang Y, Robishaw JD. Post-transcriptional regulation and subcellular localization of G-protein γ7 subunit: implications for striatal function and behavioral responses to cocaine. Front Neuroanat 2024; 18:1394659. [PMID: 38764487 PMCID: PMC11100332 DOI: 10.3389/fnana.2024.1394659] [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: 03/01/2024] [Accepted: 04/17/2024] [Indexed: 05/21/2024] Open
Abstract
The striatal D1 dopamine receptor (D1R) and A2a adenosine receptor (A2aR) signaling pathways play important roles in drug-related behaviors. These receptors activate the Golf protein comprised of a specific combination of αolfβ2γ7 subunits. During assembly, the γ7 subunit sets the cellular level of the Golf protein. In turn, the amount of Golf protein determines the collective output from both D1R and A2aR signaling pathways. This study shows the Gng7 gene encodes multiple γ7 transcripts differing only in their non-coding regions. In striatum, Transcript 1 is the predominant isoform. Preferentially expressed in the neuropil, Transcript 1 is localized in dendrites where it undergoes post-transcriptional regulation mediated by regulatory elements in its 3' untranslated region that contribute to translational suppression of the γ7 protein. Earlier studies on gene-targeted mice demonstrated loss of γ7 protein disrupts assembly of the Golf protein. In the current study, morphological analysis reveals the loss of the Golf protein is associated with altered dendritic morphology of medium spiny neurons. Finally, behavioral analysis of conditional knockout mice with cell-specific deletion of the γ7 protein in distinct populations of medium spiny neurons reveals differential roles of the Golf protein in mediating behavioral responses to cocaine. Altogether, these findings provide a better understanding of the regulation of γ7 protein expression, its impact on Golf function, and point to a new potential target and mechanisms for treating addiction and related disorders.
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Affiliation(s)
- Oliver B. Pelletier
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Gloria Brunori
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Yingcai Wang
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Janet D. Robishaw
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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3
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Millett M, Heuberger A, Castosa EM, Comite A, Wagner P, Hall D, Gallardo I, Chambers NE, Wagner L, Moehle MS. G α olf Regulates Biochemical Signaling in Neurons Associated with Movement Control and Initiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587766. [PMID: 38617339 PMCID: PMC11014607 DOI: 10.1101/2024.04.03.587766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The heterotrimeric G-protein α subunit, Gα olf , acts to transduce extracellular signals through G-protein coupled receptors (GPCRs) and stimulates adenylyl cyclase mediated production of the second messenger cyclic adenosine monophosphate. Numerous mutations in the GNAL gene, which encodes Gα olf , have been identified as causative for an adult-onset dystonia. These mutations disrupt GPCR signaling cascades in in vitro assays through several mechanisms, and this disrupted signaling is hypothesized to lead to dystonic motor symptoms in patients. However, the cells and circuits that mutations in GNAL corrupt are not well understood. Published patterns of Gα olf expression outside the context of the striatum are sparse, conflicting, often lack cell type specificity, and may be confounded by expression of the close GNAL homolog of GNAS . Here, we use RNAScope in-situ hybridization to quantitatively characterize Gnal mRNA expression in brain tissue from wildtype C57BL/6J adult mice. We observed widespread expression of Gnal puncta throughout the brain, suggesting Gα olf is expressed in more brain structures and neuron types than previously accounted for. We quantify transcripts at a single cell level, and use neuron type specific markers to further classify and understand patterns of GNAL expression. Our data suggests that brain regions classically associated with motor control, initiation, and regulation show the highest expression of GNAL , with Purkinje Cells of the cerebellum showing the highest expression of any neuron type examined. Subsequent conditional Gnal knockout in Purkinje cells led to markedly decreased intracellular cAMP levels and downstream cAMP-dependent enzyme activation. Our work provides a detailed characterization of Gnal expression throughout the brain and the biochemical consequences of loss of Gα olf signaling in vivo in neurons that highly express Gnal .
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4
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Duan H, Chen B, Wang W, Luo H. Identification of GNG7 as a novel biomarker and potential therapeutic target for gastric cancer via bioinformatic analysis and in vitro experiments. Aging (Albany NY) 2023; 15:1445-1474. [PMID: 36863706 PMCID: PMC10042700 DOI: 10.18632/aging.204545] [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: 10/31/2022] [Accepted: 02/16/2023] [Indexed: 03/04/2023]
Abstract
Gastric cancer (GC) is one of the most common malignancies with unfavorable prognoses. The present study aimed to identify novel biomarkers or potential therapeutic targets in GC via bioinformatic analysis and in vitro experiments. The Gene Expression Omnibus and The Cancer Genome Atlas databases were used to screen the differentially expressed genes (DEGs). After protein-protein interaction network construction, both module and prognostic analyses were performed to identify prognosis-related genes in GC. The expression patterns and functions of G protein γ subunit 7 (GNG7) in GC were then visualized in multiple databases and further verified using in vitro experiments. A total of 897 overlapping DEGs were detected and 20 hub genes were identified via systematic analysis. After accessing the prognostic value of the hub genes using the online server Kaplan-Meier plotter, a six-gene prognostic signature was identified, which was also significantly correlated with the process of immune infiltration in GC. The results of open-access database analyses suggested that GNG7 is downregulated in GC; this downregulation was associated with tumor progression. Furthermore, the functional enrichment analysis unveiled that the GNG7-coexpressed genes or gene sets were closely correlated with the proliferation and cell cycle processes of GC cells. Finally, in vitro experiments further confirmed that GNG7 overexpression inhibited GC cell proliferation, colony formation, and cell cycle progression and induced apoptosis. As a tumor suppressor gene, GNG7 suppressed the growth of GC cells via cell cycle blockade and apoptosis induction and thus may be used as a potential biomarker and therapeutic target for GC.
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Affiliation(s)
- Houyu Duan
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, P.R. China
| | - Biao Chen
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, P.R. China
| | - Wei Wang
- Department of Hepatobiliary Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, P.R. China
| | - Hesheng Luo
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, P.R. China
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Kankanamge D, Tennakoon M, Karunarathne A, Gautam N. G protein gamma subunit, a hidden master regulator of GPCR signaling. J Biol Chem 2022; 298:102618. [PMID: 36272647 PMCID: PMC9678972 DOI: 10.1016/j.jbc.2022.102618] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022] Open
Abstract
Heterotrimeric G proteins (αβγ subunits) that are activated by G protein-coupled receptors (GPCRs) mediate the biological responses of eukaryotic cells to extracellular signals. The α subunits and the tightly bound βγ subunit complex of G proteins have been extensively studied and shown to control the activity of effector molecules. In contrast, the potential roles of the large family of γ subunits have been less studied. In this review, we focus on present knowledge about these proteins. Induced loss of individual γ subunit types in animal and plant models result in strikingly distinct phenotypes indicating that γ subtypes play important and specific roles. Consistent with these findings, downregulation or upregulation of particular γ subunit types result in various types of cancers. Clues about the mechanistic basis of γ subunit function have emerged from imaging the dynamic behavior of G protein subunits in living cells. This shows that in the basal state, G proteins are not constrained to the plasma membrane but shuttle between membranes and on receptor activation βγ complexes translocate reversibly to internal membranes. The translocation kinetics of βγ complexes varies widely and is determined by the membrane affinity of the associated γ subtype. On translocating, some βγ complexes act on effectors in internal membranes. The variation in translocation kinetics determines differential sensitivity and adaptation of cells to external signals. Membrane affinity of γ subunits is thus a parsimonious and elegant mechanism that controls information flow to internal cell membranes while modulating signaling responses.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Mithila Tennakoon
- Department of Chemistry, St Louis University, St Louis, Missouri, USA
| | | | - N Gautam
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Genetics, Washington University School of Medicine, St Louis, Missouri, USA.
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6
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Florio E, Serra M, Lewis RG, Kramár E, Freidberg M, Wood M, Morelli M, Borrelli E. D2R signaling in striatal spiny neurons modulates L-DOPA induced dyskinesia. iScience 2022; 25:105263. [PMID: 36274959 PMCID: PMC9579025 DOI: 10.1016/j.isci.2022.105263] [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: 06/08/2022] [Revised: 07/19/2022] [Accepted: 09/25/2022] [Indexed: 11/07/2022] Open
Abstract
Degeneration of dopaminergic neurons leads to Parkinson's disease (PD), characterized by reduced levels of striatal dopamine (DA) and impaired voluntary movements. DA replacement is achieved by levodopa treatment which in long-term causes involuntary movements or dyskinesia. Dyskinesia is linked to the pulsatile activation of D1 receptors of the striatal medium spiny neurons (MSNs) forming the direct output pathway (dMSNs). The contribution of DA stimulation of D2R in MSNs of the indirect pathway (iMSNs) is less clear. Using the 6-hydroxydopamine model of PD, here we show that loss of DA-mediated inhibition of these neurons intensifies levodopa-induced dyskinesia (LID) leading to reprogramming of striatal gene expression. We propose that the motor impairments characteristic of PD and of its therapy are critically dependent on D2R-mediated iMSNs activity. D2R signaling not only filters inputs to the striatum but also indirectly regulates dMSNs mediated responses.
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Affiliation(s)
- Ermanno Florio
- Department of Microbiology & Molecular Genetics, INSERM U1233, Center for Epigenetics and Metabolism, 308 Sprague Hall, University of California, Irvine, Irvine, CA 92697, USA
| | - Marcello Serra
- Department of Biomedical Sciences, Section of Neuroscience, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy
| | - Robert G. Lewis
- Department of Microbiology & Molecular Genetics, INSERM U1233, Center for Epigenetics and Metabolism, 308 Sprague Hall, University of California, Irvine, Irvine, CA 92697, USA
| | - Enikö Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, 200 Qureshey Research Lab., Irvine, CA 92697, USA
| | - Michael Freidberg
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, CA 92697, USA
| | - Marcello Wood
- Department of Neurobiology and Behavior, University of California, Irvine, 200 Qureshey Research Lab., Irvine, CA 92697, USA
| | - Micaela Morelli
- Department of Biomedical Sciences, Section of Neuroscience, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy
| | - Emiliana Borrelli
- Department of Microbiology & Molecular Genetics, INSERM U1233, Center for Epigenetics and Metabolism, 308 Sprague Hall, University of California, Irvine, Irvine, CA 92697, USA
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7
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Li X, Wang Q, Zhang D, Wu D, Liu N, Chen T. Effects of long-term administration of Q808 on hippocampal transcriptome in healthy rats. Chem Pharm Bull (Tokyo) 2022; 70:642-649. [PMID: 35831127 DOI: 10.1248/cpb.c22-00357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epilepsy treatment with antiepileptic drugs (AEDs) is usually requires for many years. Q808 is an innovative antiepileptic chemical. It exerts effective antiepileptic effect against various epilepsy models. Exploring the gene transcriptomic profile of long-term treatment of Q808 is necessary. In the present study, hippocampus RNA-sequencing was performed to reveal the transcriptome profile of rats before and after treatment of Q808 for 28 days. Results confirmed 51 differentially expressed genes (DEGs) between Q808 and healthy control groups. Gene cluster analysis showed that most upregulated DEGs linked to response to drug and nucleus, most downregulated DEGs linked to locomotory, neuronal cell body, and drug binding. Most of DEGs were enriched in the signaling transduction, substance dependence, nervous system, and neurodegenerative disease pathways. Furthermore, quantitative real-time PCR analysis confirmed that Q808 significantly increased the expression of neuroprotective genes, such as Mdk, and decreased the mRNA levels of Penk, Drd1, and Adora2a, which are highly expressed in epilepsy models. In addition, Q808 decreased the mRNA expression of Pde10A and Drd2, which are known to be closely associated with schizophrenia. Our study may provide a theoretical basis to explore the effect of Q808 on the susceptibility to epilepsy and other neurological diseases.
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Affiliation(s)
- Xiang Li
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University
| | - Qing Wang
- Jilin Provincial Academy of Traditional Chinese Medicine
| | - Dianwen Zhang
- Jilin Provincial Academy of Traditional Chinese Medicine
| | - Di Wu
- Jilin Provincial Academy of Traditional Chinese Medicine
| | - Ning Liu
- Jilin Provincial Academy of Traditional Chinese Medicine
| | - Tianli Chen
- School of Pharmacy, Changchun University of Chinese Medicine
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8
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Merighi S, Nigro M, Travagli A, Pasquini S, Borea PA, Varani K, Vincenzi F, Gessi S. A 2A Adenosine Receptor: A Possible Therapeutic Target for Alzheimer's Disease by Regulating NLRP3 Inflammasome Activity? Int J Mol Sci 2022; 23:ijms23095056. [PMID: 35563447 PMCID: PMC9101264 DOI: 10.3390/ijms23095056] [Citation(s) in RCA: 4] [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: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 02/06/2023] Open
Abstract
The A2A adenosine receptor, a member of the P1 purinergic receptor family, plays a crucial role in the pathophysiology of different neurodegenerative illnesses, including Alzheimer’s disease (AD). It regulates both neurons and glial cells, thus modulating synaptic transmission and neuroinflammation. AD is a complex, progressive neurological condition that is the leading cause of dementia in the world’s old population (>65 years of age). Amyloid peptide-β extracellular accumulation and neurofibrillary tangles constitute the principal etiologic tracts, resulting in apoptosis, brain shrinkage, and neuroinflammation. Interestingly, a growing body of evidence suggests a role of NLRP3 inflammasome as a target to treat neurodegenerative diseases. It represents a tripartite multiprotein complex including NLRP3, ASC, and procaspase-1. Its activation requires two steps that lead with IL-1β and IL-18 release through caspase-1 activation. NLRP3 inhibition provides neuroprotection, and in recent years adenosine, through the A2A receptor, has been reported to modulate NLRP3 functions to reduce organ damage. In this review, we describe the role of NLRP3 in AD pathogenesis, both alone and in connection to A2A receptor regulation, in order to highlight a novel approach to address treatment of AD.
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Affiliation(s)
- Stefania Merighi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
| | - Manuela Nigro
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
| | - Alessia Travagli
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
| | - Silvia Pasquini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy;
| | | | - Katia Varani
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
| | - Fabrizio Vincenzi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
| | - Stefania Gessi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy; (S.M.); (M.N.); (A.T.); (K.V.); (F.V.)
- Correspondence:
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9
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Pathophysiological Role and Medicinal Chemistry of A 2A Adenosine Receptor Antagonists in Alzheimer's Disease. Molecules 2022; 27:molecules27092680. [PMID: 35566035 PMCID: PMC9102440 DOI: 10.3390/molecules27092680] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 12/20/2022] Open
Abstract
The A2A adenosine receptor is a protein belonging to a family of four GPCR adenosine receptors. It is involved in the regulation of several pathophysiological conditions in both the central nervous system and periphery. In the brain, its localization at pre- and postsynaptic level in striatum, cortex, hippocampus and its effects on glutamate release, microglia and astrocyte activation account for a crucial role in neurodegenerative diseases, including Alzheimer’s disease (AD). This ailment is considered the main form of dementia and is expected to exponentially increase in coming years. The pathological tracts of AD include amyloid peptide-β extracellular accumulation and tau hyperphosphorylation, causing neuronal cell death, cognitive deficit, and memory loss. Interestingly, in vitro and in vivo studies have demonstrated that A2A adenosine receptor antagonists may counteract each of these clinical signs, representing an important new strategy to fight a disease for which unfortunately only symptomatic drugs are available. This review offers a brief overview of the biological effects mediated by A2A adenosine receptors in AD animal and human studies and reports the state of the art of A2A adenosine receptor antagonists currently in clinical trials. As an original approach, it focuses on the crucial role of pharmacokinetics and ability to pass the blood–brain barrier in the discovery of new agents for treating CNS disorders. Considering that A2A receptor antagonist istradefylline is already commercially available for Parkinson’s disease treatment, if the proof of concept of these ligands in AD is confirmed and reinforced, it will be easier to offer a new hope for AD patients.
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Ferré S, Ciruela F, Dessauer CW, González-Maeso J, Hébert TE, Jockers R, Logothetis DE, Pardo L. G protein-coupled receptor-effector macromolecular membrane assemblies (GEMMAs). Pharmacol Ther 2022; 231:107977. [PMID: 34480967 PMCID: PMC9375844 DOI: 10.1016/j.pharmthera.2021.107977] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 12/12/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest group of receptors involved in cellular signaling across the plasma membrane and a major class of drug targets. The canonical model for GPCR signaling involves three components - the GPCR, a heterotrimeric G protein and a proximal plasma membrane effector - that have been generally thought to be freely mobile molecules able to interact by 'collision coupling'. Here, we synthesize evidence that supports the existence of GPCR-effector macromolecular membrane assemblies (GEMMAs) comprised of specific GPCRs, G proteins, plasma membrane effector molecules and other associated transmembrane proteins that are pre-assembled prior to receptor activation by agonists, which then leads to subsequent rearrangement of the GEMMA components. The GEMMA concept offers an alternative and complementary model to the canonical collision-coupling model, allowing more efficient interactions between specific signaling components, as well as the integration of the concept of GPCR oligomerization as well as GPCR interactions with orphan receptors, truncated GPCRs and other membrane-localized GPCR-associated proteins. Collision-coupling and pre-assembled mechanisms are not exclusive and likely both operate in the cell, providing a spectrum of signaling modalities which explains the differential properties of a multitude of GPCRs in their different cellular environments. Here, we explore the unique pharmacological characteristics of individual GEMMAs, which could provide new opportunities to therapeutically modulate GPCR signaling.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Addiction, Intramural Research Program, NIH, DHHS, Baltimore, MD, USA.
| | - Francisco Ciruela
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, IDIBELL, University of Barcelona, L’Hospitalet de Llobregat, Spain
| | - Carmen W. Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Terence E. Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec
| | - Ralf Jockers
- University of Paris, Institute Cochin, INSERM, CNRS, Paris, France
| | - Diomedes E. Logothetis
- Laboratory of Electrophysiology, Departments of Pharmaceutical Sciences, Chemistry and Chemical Biology and Center for Drug Discovery, School of Pharmacy at the Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, Massachusetts, USA
| | - Leonardo Pardo
- Laboratory of Computational Medicine, Biostatistics Unit, Faculty of Medicine, Autonomous University of Barcelona, Bellaterra, Spain
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11
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Geertsma HM, Suk TR, Ricke KM, Horsthuis K, Parmasad JLA, Fisk ZA, Callaghan SM, Rousseaux MWC. Constitutive nuclear accumulation of endogenous alpha-synuclein in mice causes motor impairment and cortical dysfunction, independent of protein aggregation. Hum Mol Genet 2022; 31:3613-3628. [PMID: 35179202 PMCID: PMC9616578 DOI: 10.1093/hmg/ddac035] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/20/2022] [Accepted: 01/31/2022] [Indexed: 11/14/2022] Open
Abstract
A growing body of evidence suggests that nuclear alpha-synuclein (αSyn) plays a role in the pathogenesis of Parkinson’s disease (PD). However, this question has been difficult to address as controlling the localization of αSyn in experimental systems often requires protein overexpression, which affects its aggregation propensity. To overcome this, we engineered SncaNLS mice, which localize endogenous αSyn to the nucleus. We characterized these mice on a behavioral, histological and biochemical level to determine whether the increase of nuclear αSyn is sufficient to elicit PD-like phenotypes. SncaNLS mice exhibit age-dependent motor deficits and altered gastrointestinal function. We found that these phenotypes were not linked to αSyn aggregation or phosphorylation. Through histological analyses, we observed motor cortex atrophy in the absence of midbrain dopaminergic neurodegeneration. We sampled cortical proteomes of SncaNLS mice and controls to determine the molecular underpinnings of these pathologies. Interestingly, we found several dysregulated proteins involved in dopaminergic signaling, including Darpp32, Pde10a and Gng7, which we further confirmed was decreased in cortical samples of the SncaNLS mice compared with controls. These results suggest that chronic endogenous nuclear αSyn can elicit toxic phenotypes in mice, independent of its aggregation. This model raises key questions related to the mechanism of αSyn toxicity in PD and provides a new model to study an underappreciated aspect of PD pathogenesis.
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Affiliation(s)
- Haley M Geertsma
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
| | - Terry R Suk
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
| | - Konrad M Ricke
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Kyra Horsthuis
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
| | - Jean-Louis A Parmasad
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
| | - Zoe A Fisk
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Steve M Callaghan
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H8M5, Canada
| | - Maxime W C Rousseaux
- To whom correspondence should be addressed at: University of Ottawa, 451 Smyth Road, Ottawa, K1H8M5, Canada. Tel: +1 6138625800 ext. 8611;
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12
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Jones-Tabah J, Mohammad H, Paulus EG, Clarke PBS, Hébert TE. The Signaling and Pharmacology of the Dopamine D1 Receptor. Front Cell Neurosci 2022; 15:806618. [PMID: 35110997 PMCID: PMC8801442 DOI: 10.3389/fncel.2021.806618] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/23/2021] [Indexed: 12/30/2022] Open
Abstract
The dopamine D1 receptor (D1R) is a Gαs/olf-coupled GPCR that is expressed in the midbrain and forebrain, regulating motor behavior, reward, motivational states, and cognitive processes. Although the D1R was initially identified as a promising drug target almost 40 years ago, the development of clinically useful ligands has until recently been hampered by a lack of suitable candidate molecules. The emergence of new non-catechol D1R agonists, biased agonists, and allosteric modulators has renewed clinical interest in drugs targeting this receptor, specifically for the treatment of motor impairment in Parkinson's Disease, and cognitive impairment in neuropsychiatric disorders. To develop better therapeutics, advances in ligand chemistry must be matched by an expanded understanding of D1R signaling across cell populations in the brain, and in disease states. Depending on the brain region, the D1R couples primarily to either Gαs or Gαolf through which it activates a cAMP/PKA-dependent signaling cascade that can regulate neuronal excitability, stimulate gene expression, and facilitate synaptic plasticity. However, like many GPCRs, the D1R can signal through multiple downstream pathways, and specific signaling signatures may differ between cell types or be altered in disease. To guide development of improved D1R ligands, it is important to understand how signaling unfolds in specific target cells, and how this signaling affects circuit function and behavior. In this review, we provide a summary of D1R-directed signaling in various neuronal populations and describe how specific pathways have been linked to physiological and behavioral outcomes. In addition, we address the current state of D1R drug development, including the pharmacology of newly developed non-catecholamine ligands, and discuss the potential utility of D1R-agonists in Parkinson's Disease and cognitive impairment.
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13
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Merighi S, Borea PA, Varani K, Vincenzi F, Jacobson KA, Gessi S. A 2A Adenosine Receptor Antagonists in Neurodegenerative Diseases. Curr Med Chem 2022; 29:4138-4151. [PMID: 34844537 PMCID: PMC9148371 DOI: 10.2174/0929867328666211129122550] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/07/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common form of dementia worldwide, with approximately 6 million cases reported in America in 2020. The clinical signs of AD include cognitive dysfunction, apathy, anxiety and neuropsychiatric signs, and pathogenetic mechanisms that involve amyloid peptide-β extracellular accumulation and tau hyperphosphorylation. Unfortunately, current drugs to treat AD can provide only symptomatic relief but are not disease-modifying molecules able to revert AD progression. The endogenous modulator adenosine, through A2A receptor activation, plays a role in synaptic loss and neuroinflammation, which are crucial for cognitive impairment and memory damage. OBJECTIVE In this review, recent advances covering A2A adenosine receptor antagonists will be extensively reviewed, providing a basis for the rational design of future A2A inhibitors. METHODS Herein, the literature on A2A adenosine receptors and their role in synaptic plasticity and neuroinflammation, as well as the effects of A2A antagonism in animal models of AD and in humans, are reviewed. Furthermore, current chemical and structure-based strategies are presented. RESULTS Caffeine, the most widely consumed natural product stimulant and an A2A antagonist, improves human memory. Similarly, synthetic A2A receptor antagonists, as described in this review, may provide a means to fight AD. CONCLUSION This review highlights the clinical potential of A2A adenosine receptor antagonists as a novel approach to treat patients with AD.
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Affiliation(s)
- Stefania Merighi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy;,Address correspondence to these authors at the Department Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy; ; ; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States;
| | | | - Katia Varani
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy
| | - Fabrizio Vincenzi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States,Address correspondence to these authors at the Department Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy; ; ; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States;
| | - Stefania Gessi
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy;,Address correspondence to these authors at the Department Translational Medicine and for Romagna, University of Ferrara, 44121, Ferrara, Italy; ; ; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States;
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14
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Yim YY, McDonald WH, Betke KM, Kaya A, Hyde K, Erreger K, Gilsbach R, Hein L, Hamm HE. Specificities of Gβγ subunits for the SNARE complex before and after stimulation of α 2a-adrenergic receptors. Sci Signal 2021; 14:eabc4970. [PMID: 34932372 DOI: 10.1126/scisignal.abc4970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Ligand binding to G protein–coupled receptors (GPCRs), such as the α2a-adrenergic receptor (α2aAR), results in the activation of heterotrimeric G proteins, which consist of functionally distinct Gα subunits and Gβγ dimers. α2aAR-dependent inhibition of synaptic transmission regulates functions such as spontaneous locomotor activity, anesthetic sparing, and working memory enhancement and requires the soluble NSF attachment protein receptor (SNARE) complex, a Gβγ effector. To understand how the Gβγ-SNARE complex underlies the α2aAR-dependent inhibition of synaptic transmission, we examined the specificity of Gβγ subunits for the SNARE complex in adrenergic neurons, in which auto-α2aARs respond to epinephrine released from these neurons, and nonadrenergic neurons, in which hetero-α2aARs respond to epinephrine released from other neurons. We performed a quantitative, targeted multiple reaction monitoring proteomic analysis of Gβ and Gγ subunits bound to the SNARE complex in synaptosomes from mouse brains. In the absence of stimulation of auto-α2aARs, Gβ1 and Gγ3 interacted with the SNARE complex. However, Gβ1, Gβ2, and Gγ3 were found in the complex when auto-α2aARs were activated by epinephrine. Further understanding of the specific usage of distinct Gβγ subunits in vivo may provide insights into the homeostatic regulation of synaptic transmission and the mechanisms of dysfunction that occur in neurological diseases.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - W Hayes McDonald
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Katherine M Betke
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Ali Kaya
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Karren Hyde
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kevin Erreger
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Ralf Gilsbach
- Fachbereich Medizin, Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Lutz Hein
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Heidi E Hamm
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
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15
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Selective Manipulation of G-Protein γ 7 Subunit in Mice Provides New Insights into Striatal Control of Motor Behavior. J Neurosci 2021; 41:9065-9081. [PMID: 34544837 DOI: 10.1523/jneurosci.1211-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/26/2021] [Accepted: 09/11/2021] [Indexed: 01/15/2023] Open
Abstract
Stimulatory coupling of dopamine D1 (D1R) and adenosine A2A receptors (A2AR) to adenylyl cyclase within the striatum is mediated through a specific Gαolfβ2γ7 heterotrimer to ultimately modulate motor behaviors. To dissect the individual roles of the Gαolfβ2γ7 heterotrimer in different populations of medium spiny neurons (MSNs), we produced and characterized conditional mouse models, in which the Gng7 gene was deleted in either the D1R- or A2AR/D2R-expressing MSNs. We show that conditional loss of γ7 disrupts the cell type-specific assembly of the Gαolfβ2γ7 heterotrimer, thereby identifying its circumscribed roles acting downstream of either the D1Rs or A2ARs in coordinating motor behaviors, including in vivo responses to psychostimulants. We reveal that Gαolfβ2γ7/cAMP signal in D1R-MSNs does not impact spontaneous and amphetamine-induced locomotor behaviors in male and female mice, while its loss in A2AR/D2R-MSNs results in a hyperlocomotor phenotype and enhanced locomotor response to amphetamine. Additionally, Gαolfβ2γ7/cAMP signal in either D1R- or A2AR/D2R-expressing MSNs is not required for the activation of PKA signaling by amphetamine. Finally, we show that Gαolfβ2γ7 signaling acting downstream of D1Rs is selectively implicated in the acute locomotor-enhancing effects of morphine. Collectively, these results support the general notion that receptors use specific Gαβγ proteins to direct the fidelity of downstream signaling pathways and to elicit a diverse repertoire of cellular functions. Specifically, these findings highlight the critical role for the γ7 protein in determining the cellular level, and hence, the function of the Gαolfβ2γ7 heterotrimer in several disease states associated with dysfunctional striatal signaling.SIGNIFICANCE STATEMENT Dysfunction or imbalance of cAMP signaling in the striatum has been linked to several neurologic and neuropsychiatric disorders, including Parkinson's disease, dystonia, schizophrenia, and drug addiction. By genetically targeting the γ7 subunit in distinct striatal neuronal subpopulations in mice, we demonstrate that the formation and function of the Gαolfβ2γ7 heterotrimer, which represents the rate-limiting step for cAMP production in the striatum, is selectively disrupted. Furthermore, we reveal cell type-specific roles for Gαolfβ2γ7-mediated cAMP production in the control of spontaneous locomotion as well as behavioral and molecular responses to psychostimulants. Our findings identify the γ7 protein as a novel therapeutic target for disease states associated with dysfunctional striatal cAMP signaling.
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16
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Tennakoon M, Senarath K, Kankanamge D, Ratnayake K, Wijayaratna D, Olupothage K, Ubeysinghe S, Martins-Cannavino K, Hébert TE, Karunarathne A. Subtype-dependent regulation of Gβγ signalling. Cell Signal 2021; 82:109947. [PMID: 33582184 PMCID: PMC8026654 DOI: 10.1016/j.cellsig.2021.109947] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/04/2023]
Abstract
G protein-coupled receptors (GPCRs) transmit information to the cell interior by transducing external signals to heterotrimeric G protein subunits, Gα and Gβγ subunits, localized on the inner leaflet of the plasma membrane. Though the initial focus was mainly on Gα-mediated events, Gβγ subunits were later identified as major contributors to GPCR-G protein signalling. A broad functional array of Gβγ signalling has recently been attributed to Gβ and Gγ subtype diversity, comprising 5 Gβ and 12 Gγ subtypes, respectively. In addition to displaying selectivity towards each other to form the Gβγ dimer, numerous studies have identified preferences of distinct Gβγ combinations for specific GPCRs, Gα subtypes and effector molecules. Importantly, Gβ and Gγ subtype-dependent regulation of downstream effectors, representing a diverse range of signalling pathways and physiological functions have been found. Here, we review the literature on the repercussions of Gβ and Gγ subtype diversity on direct and indirect regulation of GPCR/G protein signalling events and their physiological outcomes. Our discussion additionally provides perspective in understanding the intricacies underlying molecular regulation of subtype-specific roles of Gβγ signalling and associated diseases.
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Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kanishka Senarath
- Genetics and Molecular Biology Unit, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dhanushan Wijayaratna
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Koshala Olupothage
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | | | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada.
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
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17
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Diversity of the Gβγ complexes defines spatial and temporal bias of GPCR signaling. Cell Syst 2021; 12:324-337.e5. [PMID: 33667409 DOI: 10.1016/j.cels.2021.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 12/09/2020] [Accepted: 02/04/2021] [Indexed: 01/04/2023]
Abstract
The signal transduction by G-protein-coupled receptors (GPCRs) is mediated by heterotrimeric G proteins composed from one of the 16 Gα subunits and the inseparable Gβγ complex assembled from a repertoire of 5 Gβ and 12 Gγ subunits. However, the functional role of compositional diversity in Gβγ complexes has been elusive. Using optical biosensors, we examined the function of all Gβγ combinations in living cells and uncovered two major roles of Gβγ diversity. First, we demonstrate that the identity of Gβγ subunits greatly influences the kinetics and efficacy of GPCR responses at the plasma membrane. Second, we show that different Gβγ combinations are selectively dispatched from the plasma membrane to various cellular organelles on a timescale from milliseconds to minutes. We describe the mechanisms regulating these processes and document their implications for GPCR signaling via various Gα subunits, thereby illustrating a role for the compositional diversity of G protein heterotrimers.
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18
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Yu-Taeger L, Ott T, Bonsi P, Tomczak C, Wassouf Z, Martella G, Sciamanna G, Imbriani P, Ponterio G, Tassone A, Schulze-Hentrich JM, Goodchild R, Riess O, Pisani A, Grundmann-Hauser K, Nguyen HP. Impaired dopamine- and adenosine-mediated signaling and plasticity in a novel rodent model for DYT25 dystonia. Neurobiol Dis 2019; 134:104634. [PMID: 31678405 DOI: 10.1016/j.nbd.2019.104634] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/19/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Dystonia is a neurological movement disorder characterized by sustained or intermittent involuntary muscle contractions. Loss-of-function mutations in the GNAL gene have been identified to be the cause of "isolated" dystonia DYT25. The GNAL gene encodes for the guanine nucleotide-binding protein G(olf) subunit alpha (Gαolf), which is mainly expressed in the olfactory bulb and the striatum and functions as a modulator during neurotransmission coupling with D1R and A2AR. Previously, heterozygous Gαolf -deficient mice (Gnal+/-) have been generated and showed a mild phenotype at basal condition. In contrast, homozygous deletion of Gnal in mice (Gnal-/-) resulted in a significantly reduced survival rate. In this study, using the CRISPR-Cas9 system we generated and characterized heterozygous Gnal knockout rats (Gnal+/-) with a 13 base pair deletion in the first exon of the rat Gnal splicing variant 2, a major isoform in both human and rat striatum. Gnal+/- rats showed early-onset phenotypes associated with impaired dopamine transmission, including reduction in locomotor activity, deficits in rotarod performance and an abnormal motor skill learning ability. At cellular and molecular level, we found down-regulated Arc expression, increased cell surface distribution of AMPA receptors, and the loss of D2R-dependent corticostriatal long-term depression (LTD) in Gnal+/- rats. Based on the evidence that D2R activity is normally inhibited by adenosine A2ARs, co-localized on the same population of striatal neurons, we show that blockade of A2ARs restores physiological LTD. This animal model may be a valuable tool for investigating Gαolf function and finding a suitable treatment for dystonia associated with deficient dopamine transmission.
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Affiliation(s)
- Libo Yu-Taeger
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Thomas Ott
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Core Facility Transgenic Animals, University Clinics Tuebingen, Tuebingen, Germany
| | - Paola Bonsi
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Celina Tomczak
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Zinah Wassouf
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Giuseppina Martella
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Giuseppe Sciamanna
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Paola Imbriani
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Giulia Ponterio
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Annalisa Tassone
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Julia M Schulze-Hentrich
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Rose Goodchild
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; KU Leuven, Dept. Neurosciences, Leuven, Belgium
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Antonio Pisani
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata,Rome, Italy
| | - Kathrin Grundmann-Hauser
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Centre for Rare Diseases (ZSE), University of Tuebingen, Tuebingen, Germany
| | - Huu Phuc Nguyen
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany; Department of Human Genetics, Faculty of Medicine, Ruhr University Bochum, Bochum, Germany.
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19
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The in vivo specificity of synaptic Gβ and Gγ subunits to the α 2a adrenergic receptor at CNS synapses. Sci Rep 2019; 9:1718. [PMID: 30737458 PMCID: PMC6368627 DOI: 10.1038/s41598-018-37222-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/26/2018] [Indexed: 11/21/2022] Open
Abstract
G proteins are major transducers of signals from G-protein coupled receptors (GPCRs). They are made up of α, β, and γ subunits, with 16 Gα, 5 Gβ and 12 Gγ subunits. Though much is known about the specificity of Gα subunits, the specificity of Gβγs activated by a given GPCR and that activate each effector in vivo is not known. Here, we examined the in vivo Gβγ specificity of presynaptic α2a-adrenergic receptors (α2aARs) in both adrenergic (auto-α2aARs) and non-adrenergic neurons (hetero-α2aARs) for the first time. With a quantitative MRM proteomic analysis of neuronal Gβ and Gγ subunits, and co-immunoprecipitation of tagged α2aARs from mouse models including transgenic FLAG-α2aARs and knock-in HA-α2aARs, we investigated the in vivo specificity of Gβ and Gγ subunits to auto-α2aARs and hetero-α2aARs activated with epinephrine to understand the role of Gβγ specificity in diverse physiological functions such as anesthetic sparing, and working memory enhancement. We detected Gβ2, Gγ2, Gγ3, and Gγ4 with activated auto α2aARs, whereas we found Gβ4 and Gγ12 preferentially interacted with activated hetero-α2aARs. Further understanding of in vivo Gβγ specificity to various GPCRs offers new insights into the multiplicity of genes for Gβ and Gγ, and the mechanisms underlying GPCR signaling through Gβγ subunits.
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20
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Zurawski Z, Yim YY, Alford S, Hamm HE. The expanding roles and mechanisms of G protein-mediated presynaptic inhibition. J Biol Chem 2019; 294:1661-1670. [PMID: 30710014 PMCID: PMC6364771 DOI: 10.1074/jbc.tm118.004163] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Throughout the past five decades, tremendous advancements have been made in our understanding of G protein signaling and presynaptic inhibition, many of which were published in the Journal of Biological Chemistry under the tenure of Herb Tabor as Editor-in-Chief. Here, we identify these critical advances, including the formulation of the ternary complex model of G protein-coupled receptor signaling and the discovery of Gβγ as a critical signaling component of the heterotrimeric G protein, along with the nature of presynaptic inhibition and its physiological role. We provide an overview for the discovery and physiological relevance of the two known Gβγ-mediated mechanisms for presynaptic inhibition: first, the action of Gβγ on voltage-gated calcium channels to inhibit calcium influx to the presynaptic active zone and, second, the direct binding of Gβγ to the SNARE complex to displace synaptotagmin downstream of calcium entry, which has been demonstrated to be important in neurons and secretory cells. These two mechanisms act in tandem with each other in a synergistic manner to provide more complete spatiotemporal control over neurotransmitter release.
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Affiliation(s)
- Zack Zurawski
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600; Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois 60612-7308
| | - Yun Young Yim
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600
| | - Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois 60612-7308
| | - Heidi E Hamm
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600.
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21
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Abstract
Modulation of neurotransmitter exocytosis by activated Gi/o coupled G-protein coupled receptors (GPCRs) is a universal regulatory mechanism used both to avoid overstimulation and to influence circuitry. One of the known modulation mechanisms is the interaction between Gβγ and the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNAREs). There are 5 Gβ and 12 Gγ subunits, but specific Gβγs activated by a given GPCR and the specificity to effectors, such as SNARE, in vivo are not known. Although less studied, Gβγ binding to the exocytic fusion machinery (i.e. SNARE) provides a more direct regulatory mechanism for neurotransmitter release. Here, we review some recent insights in the architecture of the synaptic terminal, modulation of synaptic transmission, and implications of G protein modulation of synaptic transmission in diseases. Numerous presynaptic proteins are involved in the architecture of synaptic terminals, particularly the active zone, and their importance in the regulation of exocytosis is still not completely understood. Further understanding of the Gβγ-SNARE interaction and the architecture and mechanisms of exocytosis may lead to the discovery of novel therapeutic targets to help patients with various disorders such as hypertension, attention-deficit/hyperactivity disorder, post-traumatic stress disorder, and acute/chronic pain.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States.
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Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors. eNeuro 2018; 5:eN-NWR-0144-18. [PMID: 29911170 PMCID: PMC6001135 DOI: 10.1523/eneuro.0144-18.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 11/21/2022] Open
Abstract
The heterotrimeric G-protein transducin mediates visual signaling in vertebrate photoreceptor cells. Many aspects of the function of transducin were learned from knock-out mice lacking its individual subunits. Of particular interest is the knockout of its rod-specific γ-subunit (Gγ1). Two studies using independently generated mice documented that this knockout results in a considerable >60-fold reduction in the light sensitivity of affected rods, but provided different interpretations of how the remaining α-subunit (Gαt) mediates phototransduction without its cognate Gβ1γ1-subunit partner. One study found that the light sensitivity reduction matched a corresponding reduction in Gαt content in the light-sensing rod outer segments and proposed that Gαt activation is supported by remaining Gβ1 associating with other Gγ subunits naturally expressed in photoreceptors. In contrast, the second study reported the same light sensitivity loss but a much lower, only approximately sixfold, reduction of Gαt and proposed that the light responses of these rods do not require Gβγ at all. To resolve this controversy and elucidate the mechanism driving visual signaling in Gγ1 knock-out rods, we analyzed both mouse lines side by side. We first determined that the outer segments of both mice have identical Gαt content, which is reduced ∼65-fold from the wild-type (WT) level. We further demonstrated that the remaining Gβ1 is present in a complex with endogenous Gγ2 and Gγ3 subunits and that these complexes exist in wild-type rods as well. Together, these results argue against the idea that Gαt alone supports light responses of Gγ1 knock-out rods and suggest that Gβ1γ1 is not unique in its ability to mediate vertebrate phototransduction.
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23
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Senarath K, Payton JL, Kankanamge D, Siripurapu P, Tennakoon M, Karunarathne A. Gγ identity dictates efficacy of Gβγ signaling and macrophage migration. J Biol Chem 2018; 293:2974-2989. [PMID: 29317505 DOI: 10.1074/jbc.ra117.000872] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/04/2018] [Indexed: 11/06/2022] Open
Abstract
G protein βγ subunit (Gβγ) is a major signal transducer and controls processes ranging from cell migration to gene transcription. Despite having significant subtype heterogeneity and exhibiting diverse cell- and tissue-specific expression levels, Gβγ is often considered a unified signaling entity with a defined functionality. However, the molecular and mechanistic basis of Gβγ's signaling specificity is unknown. Here, we demonstrate that Gγ subunits, bearing the sole plasma membrane (PM)-anchoring motif, control the PM affinity of Gβγ and thereby differentially modulate Gβγ effector signaling in a Gγ-specific manner. Both Gβγ signaling activity and the migration rate of macrophages are strongly dependent on the PM affinity of Gγ. We also found that the type of C-terminal prenylation and five to six pre-CaaX motif residues at the PM-interacting region of Gγ control the PM affinity of Gβγ. We further show that the overall PM affinity of the Gβγ pool of a cell type is a strong predictor of its Gβγ signaling-activation efficacy. A kinetic model encompassing multiple Gγ types and parameterized for empirical Gβγ behaviors not only recapitulated experimentally observed signaling of Gβγ, but also suggested a Gγ-dependent, active-inactive conformational switch for the PM-bound Gβγ, regulating effector signaling. Overall, our results unveil crucial aspects of signaling and cell migration regulation by Gγ type-specific PM affinities of Gβγ.
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Affiliation(s)
- Kanishka Senarath
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - John L Payton
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Praneeth Siripurapu
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606.
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24
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Yano H, Provasi D, Cai NS, Filizola M, Ferré S, Javitch JA. Development of novel biosensors to study receptor-mediated activation of the G-protein α subunits G s and G olf. J Biol Chem 2017; 292:19989-19998. [PMID: 29042444 PMCID: PMC5723988 DOI: 10.1074/jbc.m117.800698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/02/2017] [Indexed: 11/06/2022] Open
Abstract
Gαs (Gs) and Gαolf (Golf) are highly homologous G-protein α subunits that activate adenylate cyclase, thereby serving as crucial mediators of intracellular signaling. Because of their dramatically different brain expression patterns, we studied similarities and differences between their activation processes with the aim of comparing their receptor coupling mechanisms. We engineered novel luciferase- and Venus-fused Gα constructs that can be used in bioluminescence resonance energy transfer assays. In conjunction with molecular simulations, these novel biosensors were used to determine receptor activation-induced changes in conformation. Relative movements in Gs were consistent with the crystal structure of β2 adrenergic receptor in complex with Gs Conformational changes in Golf activation are shown to be similar to those in Gs Overall the current study reveals general similarities between Gs and Golf activation at the molecular level and provides a novel set of tools to search for Gs- and Golf-specific receptor pharmacology. In view of the wide functional and pharmacological roles of Gs- and Golf-coupled dopamine D1 receptor and adenosine A2A receptor in the brain and other organs, elucidating their differential structure-function relationships with Gs and Golf might provide new approaches for the treatment of a variety of neuropsychiatric disorders. In particular, these novel biosensors can be used to reveal potentially therapeutic dopamine D1 receptor and adenosine A2A receptor ligands with functionally selective properties between Gs and Golf signaling.
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Affiliation(s)
- Hideaki Yano
- National Institute on Drug Abuse, Baltimore, Maryland 21224.
| | - Davide Provasi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Ning Sheng Cai
- National Institute on Drug Abuse, Baltimore, Maryland 21224
| | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Sergi Ferré
- National Institute on Drug Abuse, Baltimore, Maryland 21224
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians & Surgeons, Columbia University, New York, New York 10032; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032.
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25
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Yim YY, McDonald WH, Hyde K, Cruz-Rodríguez O, Tesmer JJG, Hamm HE. Quantitative Multiple-Reaction Monitoring Proteomic Analysis of Gβ and Gγ Subunits in C57Bl6/J Brain Synaptosomes. Biochemistry 2017; 56:5405-5416. [PMID: 28880079 DOI: 10.1021/acs.biochem.7b00433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Gβγ dimers are one of the essential signaling units of activated G protein-coupled receptors (GPCRs). There are five Gβ and 12 Gγ subunits in humans; numerous studies have demonstrated that different Gβ and Gγ subunits selectively interact to form unique Gβγ dimers, which in turn may target specific receptors and effectors. Perturbation of Gβγ signaling can lead to impaired physiological responses. Moreover, previous targeted multiple-reaction monitoring (MRM) studies of Gβ and Gγ subunits have shown distinct regional and subcellular localization patterns in four brain regions. Nevertheless, no studies have quantified or compared their individual protein levels. In this study, we have developed a quantitative MRM method not only to quantify but also to compare the protein abundance of neuronal Gβ and Gγ subunits. In whole and fractionated crude synaptosomes, we were able to identify the most abundant neuronal Gβ and Gγ subunits and their subcellular localizations. For example, Gβ1 was mostly localized at the membrane while Gβ2 was evenly distributed throughout synaptosomal fractions. The protein expression levels and subcellular localizations of Gβ and Gγ subunits may affect the Gβγ dimerization and Gβγ-effector interactions. This study offers not only a new tool for quantifying and comparing Gβ and Gγ subunits but also new insights into the in vivo distribution of Gβ and Gγ subunits, and Gβγ dimer assembly in normal brain function.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University , Nashville, Tennessee 37232-6600, United States
| | - W Hayes McDonald
- Department of Biochemistry, Vanderbilt University , Nashville, Tennessee 37232-6600, United States
| | - Karren Hyde
- Department of Pharmacology, Vanderbilt University , Nashville, Tennessee 37232-6600, United States
| | | | | | - Heidi E Hamm
- Department of Pharmacology, Vanderbilt University , Nashville, Tennessee 37232-6600, United States
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26
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Kurtenbach S, Gießl A, Strömberg S, Kremers J, Atorf J, Rasche S, Neuhaus EM, Hervé D, Brandstätter JH, Asan E, Hatt H, Kilimann MW. The BEACH Protein LRBA Promotes the Localization of the Heterotrimeric G-protein G olf to Olfactory Cilia. Sci Rep 2017; 7:8409. [PMID: 28814779 PMCID: PMC5559528 DOI: 10.1038/s41598-017-08543-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
BEACH domain proteins are involved in membrane protein traffic and human diseases, but their molecular mechanisms are not understood. The BEACH protein LRBA has been implicated in immune response and cell proliferation, and human LRBA mutations cause severe immune deficiency. Here, we report a first functional and molecular phenotype outside the immune system of LRBA-knockout mice: compromised olfaction, manifesting in reduced electro-olfactogram response amplitude, impaired food-finding efficiency, and smaller olfactory bulbs. LRBA is prominently expressed in olfactory and vomeronasal chemosensory neurons of wild-type mice. Olfactory impairment in the LRBA-KO is explained by markedly reduced concentrations (20–40% of wild-type levels) of all three subunits αolf, β1 and γ13 of the olfactory heterotrimeric G-protein, Golf, in the sensory cilia of olfactory neurons. In contrast, cilia morphology and the concentrations of many other proteins of olfactory cilia are not or only slightly affected. LRBA is also highly expressed in photoreceptor cells, another cell type with a specialized sensory cilium and heterotrimeric G-protein-based signalling; however, visual function appeared unimpaired by the LRBA-KO. To our knowledge, this is the first observation that a BEACH protein is required for the efficient subcellular localization of a lipid-anchored protein, and of a ciliary protein.
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Affiliation(s)
- Stefan Kurtenbach
- Department of Cell Physiology, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Andreas Gießl
- Department of Biology, Animal Physiology, University of Erlangen-Nürnberg, D-91058, Erlangen, Germany
| | - Siv Strömberg
- Department of Neuroscience, Uppsala University, S-75124, Uppsala, Sweden
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, D-91054, Erlangen, Germany.,Department of Anatomy II, Friedrich-Alexander University Erlangen-Nürnberg, D-91054, Erlangen, Germany
| | - Jenny Atorf
- Department of Ophthalmology, University Hospital Erlangen, D-91054, Erlangen, Germany
| | - Sebastian Rasche
- Department of Cell Physiology, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Eva M Neuhaus
- Department of Pharmacology and Toxikology, University Hospital Jena, D-07747, Jena, Germany
| | - Denis Hervé
- Inserm UMR-S839, Institut du Fer a Moulin, Universite Pierre et Marie Curie, F-75005, Paris, France
| | | | - Esther Asan
- Institute of Anatomy and Cell Biology, University of Würzburg, D-97070, Würzburg, Germany
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Manfred W Kilimann
- Department of Neuroscience, Uppsala University, S-75124, Uppsala, Sweden. .,Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, D-37075, Göttingen, Germany.
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27
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Heterozygous Gnal Mice Are a Novel Animal Model with Which to Study Dystonia Pathophysiology. J Neurosci 2017; 37:6253-6267. [PMID: 28546310 DOI: 10.1523/jneurosci.1529-16.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 04/15/2017] [Accepted: 05/10/2017] [Indexed: 12/26/2022] Open
Abstract
Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions and its pathophysiological mechanisms are still poorly understood. Dominant mutations of the GNAL gene are a cause of isolated dystonia (DYT25) in patients. Some mutations result in a complete loss of function of the encoded protein, Gαolf, an adenylyl-cyclase-stimulatory G-protein highly enriched in striatal projection neurons, where it mediates the actions of dopamine and adenosine. We used male and female heterozygous Gnal knock-out mice (Gnal+/-) to study how GNAL haplodeficiency is implicated in dystonia. In basal conditions, no overt dystonic movements or postures or change in locomotor activity were observed. However, Gnal haploinsufficiency altered self-grooming, motor coordination, and apparent motivation in operant conditioning, as well as spine morphology and phospho-CaMKIIβ in the striatum. After systemic administration of oxotremorine, an unselective cholinergic agonist, Gnal+/- mice developed more abnormal postures and movements than WT mice. These effects were not caused by seizures as indicated by EEG recordings. They were prevented by the M1-preferring muscarinic antagonists, telenzepine, pirenzepine, and trihexyphenidyl, which alleviate dystonic symptoms in patients. The motor defects were worsened by mecamylamine, a selective nicotinic antagonist. These oxotremorine-induced abnormalities in Gnal+/- mice were replicated by oxotremorine infusion into the striatum, but not into the cerebellum, indicating that defects in striatal neurons favor the appearance of dystonia-like movement alterations after oxotremorine. Untreated and oxotremorine-treated Gnal+/- mice provide a model of presymptomic and symptomatic stages of DYT25-associated dystonia, respectively, and clues about the mechanisms underlying dystonia pathogenesis.SIGNIFICANCE STATEMENT Adult-onset dystonia DYT25 is caused by dominant loss-of-function mutations of GNAL, a gene encoding the stimulatory G-protein Gαolf, which is critical for activation of the cAMP pathway in the striatal projection neurons. Here, we demonstrate that Gnal-haplodeficient mice have a mild neurological phenotype and display vulnerability to developing dystonic movements after systemic or intrastriatal injection of the cholinergic agonist oxotremorine. Therefore, impairment of the cAMP pathway in association with an increased cholinergic tone creates alterations in striatal neuron functions that can promote the onset of dystonia. Our results also provide evidence that untreated and oxotremorine-treated Gnal-haplodeficient mice are powerful models with which to study presymptomic and symptomatic stages of DYT25-associated dystonia, respectively.
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28
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Lohmann K, Masuho I, Patil DN, Baumann H, Hebert E, Steinrücke S, Trujillano D, Skamangas NK, Dobricic V, Hüning I, Gillessen-Kaesbach G, Westenberger A, Savic-Pavicevic D, Münchau A, Oprea G, Klein C, Rolfs A, Martemyanov KA. Novel GNB1 mutations disrupt assembly and function of G protein heterotrimers and cause global developmental delay in humans. Hum Mol Genet 2017; 26:1078-1086. [PMID: 28087732 PMCID: PMC6075543 DOI: 10.1093/hmg/ddx018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/22/2016] [Accepted: 12/30/2016] [Indexed: 12/31/2022] Open
Abstract
Global developmental delay (GDD), often accompanied by intellectual disability, seizures and other features is a severe, clinically and genetically highly heterogeneous childhood-onset disorder. In cases where genetic causes have been identified, de novo mutations in neuronally expressed genes are a common scenario. These mutations can be best identified by exome sequencing of parent-offspring trios. De novo mutations in the guanine nucleotide-binding protein, beta 1 (GNB1) gene, encoding the Gβ1 subunit of heterotrimeric G proteins, have recently been identified as a novel genetic cause of GDD. Using exome sequencing, we identified 14 different novel variants (2 splice site, 2 frameshift and 10 missense changes) in GNB1 in 16 pediatric patients. One mutation (R96L) was recurrently found in three ethnically diverse families with an autosomal dominant mode of inheritance. Ten variants occurred de novo in the patients. Missense changes were functionally tested for their pathogenicity by assaying the impact on complex formation with Gγ and resultant mutant Gβγ with Gα. Signaling properties of G protein complexes carrying mutant Gβ1 subunits were further analyzed by their ability to couple to dopamine D1R receptors by real-time bioluminescence resonance energy transfer (BRET) assays. These studies revealed altered functionality of the missense mutations R52G, G64V, A92T, P94S, P96L, A106T and D118G but not for L30F, H91R and K337Q. In conclusion, we demonstrate a pathogenic role of de novo and autosomal dominant mutations in GNB1 as a cause of GDD and provide insights how perturbation in heterotrimeric G protein function contributes to the disease.
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Affiliation(s)
- Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Dipak N. Patil
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hauke Baumann
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | - Eva Hebert
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | - Sofia Steinrücke
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | | | | | | | - Irina Hüning
- Institut fur Humangenetik, Universität zu Lübeck, 23538 Lübeck, Germany
| | | | - Ana Westenberger
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | | | - Alexander Münchau
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | | | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | - Arndt Rolfs
- Centogene AG, 18057 Rostock, Germany
- Centre for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
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29
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Vastagh C, Rodolosse A, Solymosi N, Liposits Z. Altered Expression of Genes Encoding Neurotransmitter Receptors in GnRH Neurons of Proestrous Mice. Front Cell Neurosci 2016; 10:230. [PMID: 27774052 PMCID: PMC5054603 DOI: 10.3389/fncel.2016.00230] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/22/2016] [Indexed: 11/13/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) neurons play a key role in the central regulation of reproduction. In proestrous female mice, estradiol triggers the pre-ovulatory GnRH surge, however, its impact on the expression of neurotransmitter receptor genes in GnRH neurons has not been explored yet. We hypothesized that proestrus is accompanied by substantial changes in the expression profile of genes coding for neurotransmitter receptors in GnRH neurons. We compared the transcriptome of GnRH neurons obtained from intact, proestrous, and metestrous female GnRH-GFP transgenic mice, respectively. About 1500 individual GnRH neurons were sampled from both groups and their transcriptome was analyzed using microarray hybridization and real-time PCR. In this study, changes in mRNA expression of genes involved in neurotransmitter signaling were investigated. Differential gene expression was most apparent in GABA-ergic (Gabbr1, Gabra3, Gabrb3, Gabrb2, Gabrg2), glutamatergic (Gria1, Gria2, Grin1, Grin3a, Grm1, Slc17a6), cholinergic (Chrnb2, Chrm4) and dopaminergic (Drd3, Drd4), adrenergic (Adra1b, Adra2a, Adra2c), adenosinergic (Adora2a, Adora2b), glycinergic (Glra), purinergic (P2rx7), and serotonergic (Htr1b) receptors. In concert with these events, expression of genes in the signaling pathways downstream to the receptors, i.e., G-proteins (Gnai1, Gnai2, Gnas), adenylate-cyclases (Adcy3, Adcy5), protein kinase A (Prkaca, Prkacb) protein kinase C (Prkca) and certain transporters (Slc1a4, Slc17a6, Slc6a17) were also changed. The marked differences found in the expression of genes involved in neurotransmitter signaling of GnRH neurons at pro- and metestrous stages of the ovarian cycle indicate the differential contribution of these neurotransmitter systems to the induction of the pre-ovulatory GnRH surge, the known prerequisite of the subsequent hormonal cascade inducing ovulation.
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Affiliation(s)
- Csaba Vastagh
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary
| | - Annie Rodolosse
- Functional Genomics Core, Institute for Research in Biomedicine (IRB Barcelona)Barcelona, Spain
| | - Norbert Solymosi
- Department of Animal Hygiene, Herd-Health and Veterinary Ethology, University of Veterinary MedicineBudapest, Hungary
| | - Zsolt Liposits
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary
- Department of Neuroscience, Faculty of Information Technology and Bionics, Pázmány Péter Catholic UniversityBudapest, Hungary
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30
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Mahmoud S, Farrag M, Ruiz-Velasco V. Gγ7 proteins contribute to coupling of nociceptin/orphanin FQ peptide (NOP) opioid receptors and voltage-gated Ca(2+) channels in rat stellate ganglion neurons. Neurosci Lett 2016; 627:77-83. [PMID: 27238748 PMCID: PMC4939115 DOI: 10.1016/j.neulet.2016.05.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/20/2016] [Accepted: 05/25/2016] [Indexed: 01/11/2023]
Abstract
The nociceptin/orphanin FQ peptide (NOP) opioid receptors regulate neurotransmitter release via inhibition of voltage-gated Ca(2+) channels (CaV2.2) in sympathetic and sensory neurons. Stimulation of NOP receptors by its endogenous agonist, nociception (Noc), leads to membrane-delimited, voltage-dependent (VD) block of CaV2.2 channel currents mediated by Gβγ protein subunits. Previously we reported that the pertussis toxin-sensitive Gαi1 and Gβ2/β4 isoforms mediate the functional coupling of NOP opioid receptors with CaV channels in rat stellate ganglion (SG) sympathetic neurons. In the present report we extended our studies by identifying the Gγ subunit that forms the heterotrimer within this signaling pathway. Small interference RNA (or siRNA) was employed to silence the expression of the natively expressed Gγ subunits. Initial PCR assays indicated that SG neurons expressed seven Gγ subunits. Silencing Gγ3 subunits did not alter signaling between NOP receptors and Ca(2+) channels. However, after Gγ7 isoforms were silenced, the Noc-mediated inhibition of CaV channels was significantly decreased when compared to SG neurons transfected with scrambled siRNA. We observed that Gγ10 and Gγ11 mRNA levels increased 2.5- and 2.7-fold, respectively, after Gγ7 subunits were silenced. However, this compensatory increase in mRNA expression did not appear to fully rescue the NOP receptor coupling efficiency. Additionally, both Gγ2 and Gγ5 levels increased 50 and 75%, respectively, while Gγ3 and Gγ4 expression levels remained relatively unchanged. Taken together, our findings suggest that the Gαi1/Gβ2(β4)/Gγ7 heterotrimeric G protein complex determines the NOP receptor-mediated modulation of CaV channels in SG neurons.
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Affiliation(s)
- Saifeldin Mahmoud
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Mohamed Farrag
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Victor Ruiz-Velasco
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, 17033, USA.
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31
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Liu J, Ji X, Li Z, Yang X, Wang W, Zhang X. G protein γ subunit 7 induces autophagy and inhibits cell division. Oncotarget 2016; 7:24832-47. [PMID: 27056891 PMCID: PMC5029746 DOI: 10.18632/oncotarget.8559] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/28/2016] [Indexed: 11/25/2022] Open
Abstract
GNG7 (G protein γ subunit 7), a subunit of heterotrimeric G protein, is ubiquitously expressed in multiple tissues but is down-regulated in various cancers. Its expression could reduce tumor volume in mice but the mechanism was not clear. Here we show that GNG7 overexpression inhibits cell proliferation and increases cell death. GNG7 level is cell cycle-dependent and it regulates actin cytoskeleton and cell division. In addition, GNG7 is an autophagy inducer, which is the first reported Gγ protein involved in autophagy. GNG7 knockdown reduces Rapamycin and starvation-induced autophagy. Further analysis reveals that GNG7 inhibits MTOR in cells, a central regulator for autophagy and cell proliferation. In conclusion, GNG7 inhibits MTOR pathway to induce autophagy and cell death, inhibits cell division by regulating actin cytoskeleton. These combined effects lead to the antitumor capacity of GNG7.
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Affiliation(s)
- Juanjuan Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- University of Science and Technology of China, Hefei, Anhui, 230036, P. R. China
| | - Xinmiao Ji
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Zhiyuan Li
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Xingxing Yang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Wenchao Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Xin Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
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32
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Xie K, Masuho I, Shih CC, Cao Y, Sasaki K, Lai CWJ, Han PL, Ueda H, Dessauer CW, Ehrlich ME, Xu B, Willardson BM, Martemyanov KA. Stable G protein-effector complexes in striatal neurons: mechanism of assembly and role in neurotransmitter signaling. eLife 2015; 4. [PMID: 26613416 PMCID: PMC4728126 DOI: 10.7554/elife.10451] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/26/2015] [Indexed: 12/23/2022] Open
Abstract
In the striatum, signaling via G protein-coupled neurotransmitter receptors is essential for motor control. Critical to this process is the effector enzyme adenylyl cyclase type 5 (AC5) that produces second messenger cAMP upon receptor-mediated activation by G protein Golf. However, the molecular organization of the Golf-AC5 signaling axis is not well understood. In this study, we report that in the striatum AC5 exists in a stable pre-coupled complex with subunits of Golf heterotrimer. We use genetic mouse models with disruption in individual components of the complex to reveal hierarchical order of interactions required for AC5-Golf stability. We further identify that the assembly of AC5-Golf complex is mediated by PhLP1 chaperone that plays central role in neurotransmitter receptor coupling to cAMP production motor learning. These findings provide evidence for the existence of stable G protein-effector signaling complexes and identify a new component essential for their assembly.
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Affiliation(s)
- Keqiang Xie
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Chien-Cheng Shih
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, United States
| | - Yan Cao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Keita Sasaki
- Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Chun Wan J Lai
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
| | - Pyung-Lim Han
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Hiroshi Ueda
- Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, United States
| | - Michelle E Ehrlich
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Baoji Xu
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Barry M Willardson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
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33
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Preti D, Baraldi PG, Moorman AR, Borea PA, Varani K. History and perspectives of A2A adenosine receptor antagonists as potential therapeutic agents. Med Res Rev 2015; 35:790-848. [PMID: 25821194 DOI: 10.1002/med.21344] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Growing evidence emphasizes that the purine nucleoside adenosine plays an active role as a local regulator in different pathologies. Adenosine is a ubiquitous nucleoside involved in various physiological and pathological functions by stimulating A1 , A2A , A2B , and A3 adenosine receptors (ARs). At the present time, the role of A2A ARs is well known in physiological conditions and in a variety of pathologies, including inflammatory tissue damage and neurodegenerative disorders. In particular, the use of selective A2A antagonists has been reported to be potentially useful in the treatment of Parkinson's disease (PD). In this review, A2A AR signal transduction pathways, together with an analysis of the structure-activity relationships of A2A antagonists, and their corresponding pharmacological roles and therapeutic potential have been presented. The initial results from an emerging polypharmacological approach are also analyzed. This approach is based on the optimization of the affinity and/or functional activity of the examined compounds toward multiple targets, such as A1 /A2A ARs and monoamine oxidase-B (MAO-B), both closely implicated in the pathogenesis of PD.
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Affiliation(s)
- Delia Preti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | | | - Pier Andrea Borea
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
| | - Katia Varani
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
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Betke KM, Rose KL, Friedman DB, Baucum AJ, Hyde K, Schey KL, Hamm HE. Differential localization of G protein βγ subunits. Biochemistry 2014; 53:2329-43. [PMID: 24568373 PMCID: PMC4004276 DOI: 10.1021/bi500091p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
G protein βγ subunits play essential roles in regulating cellular signaling cascades, yet little is known about their distribution in tissues or their subcellular localization. While previous studies have suggested specific isoforms may exhibit a wide range of distributions throughout the central nervous system, a thorough investigation of the expression patterns of both Gβ and Gγ isoforms within subcellular fractions has not been conducted. To address this, we applied a targeted proteomics approach known as multiple-reaction monitoring to analyze localization patterns of Gβ and Gγ isoforms in pre- and postsynaptic fractions isolated from cortex, cerebellum, hippocampus, and striatum. Particular Gβ and Gγ subunits were found to exhibit distinct regional and subcellular localization patterns throughout the brain. Significant differences in subcellular localization between pre- and postsynaptic fractions were observed within the striatum for most Gβ and Gγ isoforms, while others exhibited completely unique expression patterns in all four brain regions examined. Such differences are a prerequisite for understanding roles of individual subunits in regulating specific signaling pathways throughout the central nervous system.
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Affiliation(s)
- Katherine M Betke
- Department of Pharmacology, ‡Mass Spectrometry Research Center, §Department of Molecular Physiology and Biophysics, and ∥Department of Biochemistry, Vanderbilt University Medical Center , Nashville, Tennessee 37232-6600, United States
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Disruption of G-protein γ5 subtype causes embryonic lethality in mice. PLoS One 2014; 9:e90970. [PMID: 24599258 PMCID: PMC3944967 DOI: 10.1371/journal.pone.0090970] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 02/06/2014] [Indexed: 12/01/2022] Open
Abstract
Heterotrimeric G-proteins modulate many processes essential for embryonic development including cellular proliferation, migration, differentiation, and survival. Although most research has focused on identifying the roles of the various αsubtypes, there is growing recognition that similarly divergent βγ dimers also regulate these processes. In this paper, we show that targeted disruption of the mouse Gng5 gene encoding the γ5 subtype produces embryonic lethality associated with severe head and heart defects. Collectively, these results add to a growing body of data that identify critical roles for the γ subunits in directing the assembly of functionally distinct G-αβγ trimers that are responsible for regulating diverse biological processes. Specifically, the finding that loss of the G-γ5 subtype is associated with a reduced number of cardiac precursor cells not only provides a causal basis for the mouse phenotype but also raises the possibility that G-βγ5 dependent signaling contributes to the pathogenesis of human congenital heart problems.
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Gutierrez-Arenas O, Eriksson O, Hellgren Kotaleski J. Segregation and crosstalk of D1 receptor-mediated activation of ERK in striatal medium spiny neurons upon acute administration of psychostimulants. PLoS Comput Biol 2014; 10:e1003445. [PMID: 24499932 PMCID: PMC3907292 DOI: 10.1371/journal.pcbi.1003445] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 12/06/2013] [Indexed: 12/29/2022] Open
Abstract
The convergence of corticostriatal glutamate and dopamine from the midbrain in the striatal medium spiny neurons (MSN) triggers synaptic plasticity that underlies reinforcement learning and pathological conditions such as psychostimulant addiction. The increase in striatal dopamine produced by the acute administration of psychostimulants has been found to activate not only effectors of the AC5/cAMP/PKA signaling cascade such as GluR1, but also effectors of the NMDAR/Ca(2+)/RAS cascade such as ERK. The dopamine-triggered effects on both these cascades are mediated by D1R coupled to Golf but while the phosphorylation of GluR1 is affected by reductions in the available amount of Golf but not of D1R, the activation of ERK follows the opposite pattern. This segregation is puzzling considering that D1R-induced Golf activation monotonically increases with DA and that there is crosstalk from the AC5/cAMP/PKA cascade to the NMDAR/Ca(2+)/RAS cascade via a STEP (a tyrosine phosphatase). In this work, we developed a signaling model which accounts for this segregation based on the assumption that a common pool of D1R and Golf is distributed in two D1R/Golf signaling compartments. This model integrates a relatively large amount of experimental data for neurons in vivo and in vitro. We used it to explore the crosstalk topologies under which the sensitivities of the AC5/cAMP/PKA signaling cascade to reductions in D1R or Golf are transferred or not to the activation of ERK. We found that the sequestration of STEP by its substrate ERK together with the insensitivity of STEP activity on targets upstream of ERK (i.e. Fyn and NR2B) to PKA phosphorylation are able to explain the experimentally observed segregation. This model provides a quantitative framework for simulation based experiments to study signaling required for long term potentiation in MSNs.
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Affiliation(s)
- Omar Gutierrez-Arenas
- School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Olivia Eriksson
- Department of Numerical Analysis and Computer Science, Stockholm University, Stockholm, Sweden
| | - Jeanette Hellgren Kotaleski
- School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden
- Department of Numerical Analysis and Computer Science, Stockholm University, Stockholm, Sweden
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
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Cekic C, Sag D, Day YJ, Linden J. Extracellular adenosine regulates naive T cell development and peripheral maintenance. ACTA ACUST UNITED AC 2013; 210:2693-706. [PMID: 24145516 PMCID: PMC3832923 DOI: 10.1084/jem.20130249] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Adenosine receptor signaling inhibits TCR-induced activation of PI3K–Akt to reduce IL-7Rα expression on T cells, thereby regulating development and maintenance of naive T cells in the periphery. Adenosine produced as a byproduct of metabolic activity is present in all tissues and produces dose-dependent suppression of TCR signaling. Naive T cell maintenance depends on inhibition of TCR signals by environmental sensors, which are yet to be fully defined. We produced mice with a floxed adenosine A2A receptor (A2AR) gene, Adora2a, and show that either global A2AR deletion or cre-mediated T cell deletion elicits a decline in the number of naive but not memory T cells. A2AR signaling maintains naive T cells in a quiescent state by inhibiting TCR-induced activation of the phosphatidylinositide 3-kinase (PI3K)–AKT pathway, thereby reducing IL-7Rα down-regulation and naive T cell apoptosis. Patterns of IL-7Rα expression on T cells in chimeric mice reconstituted with Adora2a+/+ and Adora2a−/− bone marrow cells suggest that decreased IL-7Rα in naive T cells is a cell-intrinsic consequence of Adora2a deletion. In addition, A2AR expression increases in early thymic T cell development and contributes to progression of double-negative thymic precursors to single-positive thymocytes with increased IL-7Rα expression. Therefore, A2AR signaling regulates T cell development and maintenance to sustain normal numbers of naive T cells in the periphery.
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Affiliation(s)
- Caglar Cekic
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037
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Khan SM, Sleno R, Gora S, Zylbergold P, Laverdure JP, Labbé JC, Miller GJ, Hébert TE. The expanding roles of Gβγ subunits in G protein-coupled receptor signaling and drug action. Pharmacol Rev 2013; 65:545-77. [PMID: 23406670 DOI: 10.1124/pr.111.005603] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gβγ subunits from heterotrimeric G proteins perform a vast array of functions in cells with respect to signaling, often independently as well as in concert with Gα subunits. However, the eponymous term "Gβγ" does not do justice to the fact that 5 Gβ and 12 Gγ isoforms have evolved in mammals to serve much broader roles beyond their canonical roles in cellular signaling. We explore the phylogenetic diversity of Gβγ subunits with a view toward understanding these expanded roles in different cellular organelles. We suggest that the particular content of distinct Gβγ subunits regulates cellular activity, and that the granularity of individual Gβ and Gγ action is only beginning to be understood. Given the therapeutic potential of targeting Gβγ action, this larger view serves as a prelude to more specific development of drugs aimed at individual isoforms.
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Affiliation(s)
- Shahriar M Khan
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Room 1303, Montréal, Québec H3G 1Y6, Canada
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Gα(olf) mutation allows parsing the role of cAMP-dependent and extracellular signal-regulated kinase-dependent signaling in L-3,4-dihydroxyphenylalanine-induced dyskinesia. J Neurosci 2012; 32:5900-10. [PMID: 22539851 DOI: 10.1523/jneurosci.0837-12.2012] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Although L-3,4-dihydroxyphenylalanine (L-DOPA) remains the reference treatment of Parkinson's disease, its long-term beneficial effects are hindered by L-DOPA-induced dyskinesia (LID). In the dopamine (DA)-denervated striatum, L-DOPA activates DA D₁ receptor(D₁R) signaling, including cAMP-dependent protein kinase A (PKA) and extracellular signal-regulated kinase (ERK), two responses associated with LID. However, the cause of PKA and ERK activation, their respective contribution to LID, and their relationship are not known. In striatal neurons, D₁R activates adenylyl-cyclase through Gα(olf), a protein upregulated after lesion of DA neurons in rats and inpatients. We report here that increased Gα(olf) levels in hemiparkinsonian mice are correlated with LID after chronic L-DOPA treatment. To determine the role of this upregulation, we performed unilateral lesion in mice lacking one allele of the Gnal gene coding for Gα(olf) (Gnal⁺/⁻). Despite an increase in the lesioned striatum,Gα(olf) levels remained below those of unlesioned wild-type mice. In Gnal⁺/⁻ mice, the lesion-induced L-DOPA stimulation of cAMP/PKA-mediated phosphorylation of GluA1 Ser845 and DARPP-32 (32 kDa DA- and cAMP-regulated phosphoprotein) Thr34 was dramatically reduced, whereas ERK activation was preserved. LID occurrence was similar in Gnal⁺/⁺ and Gnal⁺/⁻ mice after a 10-d L-DOPA (20 mg/kg) treatment. Thus, in lesioned animals, Gα(olf) upregulation is critical for the activation by L-DOPA of D₁R-stimulated cAMP/PKA but not ERK signaling. Although the cAMP/PKA pathway appears to be required for LID development, our results indicate that its activation is unlikely to be the main source of LID. In contrast, the persistence of L-DOPA-induced ERK activation in Gnal⁺/⁻ mice supports its causal role in LID development.
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Girault JA. Integrating neurotransmission in striatal medium spiny neurons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:407-29. [PMID: 22351066 DOI: 10.1007/978-3-7091-0932-8_18] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The striatum is a major entry structure of the basal ganglia. Its role in information processing in close interaction with the cerebral cortex and thalamus has various behavioral consequences depending on the regions concerned, including control of body movements and motivation. A general feature of striatal information processing is the control by reward-related dopamine signals of glutamatergic striatal inputs and of their plasticity. This relies on specific sets of receptors and signaling proteins in medium-sized spiny neurons which belong to two groups, striatonigral and striatopallidal neurons. Some signaling pathways are activated only by dopamine or glutamate, but many provide multiple levels of interactions. For example, the cAMP pathway is mostly regulated by dopamine D1 receptors in striatonigral neurons, whereas the ERK pathway detects a combination of glutamate and dopamine signals and is essential for long-lasting modifications. These adaptations require changes in gene expression, and the signaling pathways linking synaptic activity to nuclear function and epigenetic changes are beginning to be deciphered. Their alteration underlies many aspects of striatal dysfunction in pathological conditions which include a decrease or an increase in dopamine transmission, as encountered in Parkinson's disease or exposure to addictive drugs, respectively.
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Affiliation(s)
- Jean-Antoine Girault
- Institut du Fer à Moulin, UMR-S 839, Inserm and Université Pierre et Marie Curie, 17 rue du Fer à Moulin, 75005 Paris, France.
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Abstract
Assembly of the G-αβγ heterotrimer is required for receptor signaling. Although much has been learned about the assembly process itself, the identities of the G-αβγ combinations that actually exist in physiological setting are largely unknown. Moreover, there is uncertainty regarding whether the individual subunits associate by a random process, or combine by a regulated process to form quasi-stable G-αβγ complexes. In this chapter, we will focus on emerging genetic -evidence that supports the latter model. Specifically, we will discuss how use of gene targeted mice has revealed preferential assembly of the striatal-specific Gα(olf)β(2)γ(7) complex occurs by a sequential process that is directed by the γ(7) subunit. The existence of specific G-αβγ complexes responsible for transducing the signals from different receptors may have profound implications by providing a possible explanation for biased agonism.
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Affiliation(s)
- Janet D Robishaw
- Weis Center for Research, Geisinger Clinic, 100 N. Academy Ave, Danville, PA, USA,
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Girault JA. Signaling in striatal neurons: the phosphoproteins of reward, addiction, and dyskinesia. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:33-62. [PMID: 22340713 DOI: 10.1016/b978-0-12-396456-4.00006-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The striatum is a deep region of the forebrain involved in action selection, control of movement, and motivation. It receives a convergent excitatory glutamate input from the cerebral cortex and the thalamus, controlled by dopamine (DA) released in response to unexpected rewards and other salient stimuli. Striatal function and its dysfunction in drug addiction or Parkinson's disease depend on the interplay between these neurotransmitters. Signaling cascades in striatal medium-sized spiny neurons (MSNs) involve multiple kinases, phosphatases, and phosphoproteins, some of which are highly enriched in these neurons. They control the properties of ion channels and the plasticity of MSNs, in part through their effects on gene transcription. This chapter summarizes signaling in MSNs and focuses on the regulation of multiple protein phosphatases through DA and glutamate receptors and the role of ERK. It is hypothesized that these pathways are particularly adapted to the specific computing properties of MSNs and the function of the basal ganglia circuits in which they participate.
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Schwindinger WF, Mirshahi UL, Baylor KA, Sheridan KM, Stauffer AM, Usefof S, Stecker MM, Mirshahi T, Robishaw JD. Synergistic roles for G-protein γ3 and γ7 subtypes in seizure susceptibility as revealed in double knock-out mice. J Biol Chem 2011; 287:7121-33. [PMID: 22207761 DOI: 10.1074/jbc.m111.308395] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The functions of different G-protein αβγ subunit combinations are traditionally ascribed to their various α components. However, the discovery of similarly diverse γ subtypes raises the possibility that they may also contribute to specificity. To test this possibility, we used a gene targeting approach to determine whether the closely related γ(3) and γ(7) subunits can perform functionally interchangeable roles in mice. In contrast to single knock-out mice that show normal survival, Gng3(-/-)Gng7(-/-) double knock-out mice display a progressive seizure disorder that dramatically reduces their median life span to only 75 days. Biochemical analyses reveal that the severe phenotype is not due to redundant roles for the two γ subunits in the same signaling pathway but rather is attributed to their unique actions in different signaling pathways. The results suggest that the γ(3) subunit is a component of a G(i/o) protein that is required for γ-aminobutyric acid, type B, receptor-regulated neuronal excitability, whereas the γ(7) subunit is a component of a G(olf) protein that is responsible for A(2A) adenosine or D(1) dopamine receptor-induced neuro-protective response. The development of this mouse model offers a novel experimental framework for exploring how signaling pathways integrate to produce normal brain function and how their combined dysfunction leads to spontaneous seizures and premature death. The results underscore the critical role of the γ subunit in this process.
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Hervé D. Identification of a specific assembly of the g protein golf as a critical and regulated module of dopamine and adenosine-activated cAMP pathways in the striatum. Front Neuroanat 2011; 5:48. [PMID: 21886607 PMCID: PMC3155884 DOI: 10.3389/fnana.2011.00048] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 07/20/2011] [Indexed: 11/16/2022] Open
Abstract
In the principal neurons of striatum (medium spiny neurons, MSNs), cAMP pathway is primarily activated through the stimulation of dopamine D1 and adenosine A2A receptors, these receptors being mainly expressed in striatonigral and striatopallidal MSNs, respectively. Since cAMP signaling pathway could be altered in various physiological and pathological circumstances, including drug addiction and Parkinson’s disease, it is of crucial importance to identify the molecular components involved in the activation of this pathway. In MSNs, cAMP pathway activation is not dependent on the classical Gs GTP-binding protein but requires a specific G protein subunit heterotrimer containing Gαolf/β2/γ7 in particular association with adenylyl cyclase type 5. This assembly forms an authentic functional signaling unit since loss of one of its members leads to defects of cAMP pathway activation in response to D1 or A2A receptor stimulation, inducing dramatic impairments of behavioral responses dependent on these receptors. Interestingly, D1 receptor (D1R)-dependent cAMP signaling is modulated by the neuronal levels of Gαolf, indicating that Gαolf represents the rate-limiting step in this signaling cascade and could constitute a critical element for regulation of D1R responses. In both Parkinsonian patients and several animal models of Parkinson’s disease, the lesion of dopamine neurons produces a prolonged elevation of Gαolf levels. This observation gives an explanation for the cAMP pathway hypersensitivity to D1R stimulation, occurring despite an unaltered D1R density. In conclusion, alterations in the highly specialized assembly of Gαolf/β2/γ7 subunits can happen in pathological conditions, such as Parkinson’s disease, and it could have important functional consequences in relation to changes in D1R signaling in the striatum.
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Wei CJ, Li W, Chen JF. Normal and abnormal functions of adenosine receptors in the central nervous system revealed by genetic knockout studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1358-79. [PMID: 21185258 DOI: 10.1016/j.bbamem.2010.12.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 12/17/2022]
Abstract
Endogenous adenosine is a widely distributed upstream regulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways that converge to contribute to the expression of an array of important brain functions. Over the past decade, the generation and characterization of genetic knockout models for all four G-protein coupled adenosine receptors, the A1 and A2A receptors in particular, has confirmed and extended the neuromodulatory and integrated role of adenosine receptors in the control of a broad spectrum of normal and abnormal brain functions. After a brief introduction of the available adenosine receptor knockout models, this review focuses on findings from the genetic knockout approach, placing particular emphasis on the most recent findings. This review is organized into two sections to separately address (i) the role of adenosine receptors in normal brain processes including neuroplasticity, sleep-wake cycle, motor function, cognition, and emotion-related behaviors; and (ii) their role in the response to various pathologic insults to brain such as ischemic stroke, neurodegeneration, or brain dysfunction/disorders. We largely limit our overview to the prominent adenosine receptor subtypes in brain-the A1 and A2A receptors-for which numerous genetic knockout studies on brain function are available. A1 and A2A receptor knockouts have provided significant new insights into adenosine's control of complex physiologic (e.g., cognition) and pathologic (e.g., neuroinflammation) phenomena. These findings extend and strengthen the support for A1 and A2A receptors in brain as therapeutic targets in several neurologic and psychiatric diseases. However, they also emphasize the importance of considering the disease context-dependent effect when developing adenosine receptor-based therapeutic strategies.
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Affiliation(s)
- Catherine J Wei
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
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Bigler Wang D, Sherman NE, Shannon JD, Leonhardt SA, Mayeenuddin LH, Yeager M, McIntire WE. Binding of β4γ5 by adenosine A1 and A2A receptors determined by stable isotope labeling with amino acids in cell culture and mass spectrometry. Biochemistry 2010; 50:207-20. [PMID: 21128647 DOI: 10.1021/bi101227y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Characterization of G protein βγ dimer isoform expression in different cellular contexts has been impeded by low levels of protein expression, broad isoform heterogeneity, and antibodies of limited specificity, sensitivity, or availability. As a new approach, we used quantitative mass spectrometry to characterize native βγ dimers associated with adenosine A(1):α(i1) and adenosine A(2A):α(S) receptor fusion proteins expressed in HEK-293 cells. Cells expressing A(1):α(i1) were cultured in media containing [(13)C(6)]Arg and [(13)C(6)]Lys and βγ labeled with heavy isotopes purified. Heavy βγ was combined with either recombinant βγ purified from Sf9 cells, βγ purified from the A(2A):α(S) expressed in HEK-293 cells cultured in standard media, or an enriched βγ fraction from HEK-293 cells. Samples were separated by SDS-PAGE, protein bands containing β and γ were excised, digested with trypsin, and separated by HPLC, and isotope ratios were analyzed by mass spectrometry. Three β isoforms, β(1), β(2), and β(4), and seven γ isoforms, γ(2), γ(4), γ(5), γ(7), γ(10), γ(11), and γ(12), were identified in the analysis. β(1) and γ(5) were most abundant in the enriched βγ fraction, and this βγ profile was generally mirrored in the fusion proteins. However, both A(2A):α(S) and A(1):α(i1) bound more β(4) and γ(5) compared to the enriched βγ fraction; also, more β(4) was associated with A(2A):α(S) than A(1):α(i1). Both fusion proteins also contained less γ(2), γ(10), and γ(12) than the enriched βγ fraction. These results suggest that preferences for particular βγ isoforms may be driven in part by structural motifs common to adenosine receptor family members.
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Affiliation(s)
- Dora Bigler Wang
- Department of Pharmacology, University of Virginia Health System, Charlottesville, 22908, United States
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