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Knight KM, Krumm BE, Kapolka NJ, Ludlam WG, Cui M, Mani S, Prytkova I, Obarow EG, Lefevre TJ, Wei W, Ma N, Huang XP, Fay JF, Vaidehi N, Smrcka AV, Slesinger PA, Logothetis DE, Martemyanov KA, Roth BL, Dohlman HG. A neurodevelopmental disorder mutation locks G proteins in the transitory pre-activated state. Nat Commun 2024; 15:6643. [PMID: 39103320 DOI: 10.1038/s41467-024-50964-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 07/25/2024] [Indexed: 08/07/2024] Open
Abstract
Many neurotransmitter receptors activate G proteins through exchange of GDP for GTP. The intermediate nucleotide-free state has eluded characterization, due largely to its inherent instability. Here we characterize a G protein variant associated with a rare neurological disorder in humans. GαoK46E has a charge reversal that clashes with the phosphate groups of GDP and GTP. As anticipated, the purified protein binds poorly to guanine nucleotides yet retains wild-type affinity for G protein βγ subunits. In cells with physiological concentrations of nucleotide, GαoK46E forms a stable complex with receptors and Gβγ, impeding effector activation. Further, we demonstrate that the mutant can be easily purified in complex with dopamine-bound D2 receptors, and use cryo-electron microscopy to determine the structure, including both domains of Gαo, without nucleotide or stabilizing nanobodies. These findings reveal the molecular basis for the first committed step of G protein activation, establish a mechanistic basis for a neurological disorder, provide a simplified strategy to determine receptor-G protein structures, and a method to detect high affinity agonist binding in cells.
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Affiliation(s)
- Kevin M Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Brian E Krumm
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nicholas J Kapolka
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - W Grant Ludlam
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences Northeastern University, Boston, MA, USA
| | - Sepehr Mani
- Department of Pharmaceutical Sciences Northeastern University, Boston, MA, USA
| | - Iya Prytkova
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Elizabeth G Obarow
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tyler J Lefevre
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Wenyuan Wei
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jonathan F Fay
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Paul A Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Kirill A Martemyanov
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Sanchez GA, Smrcka AV, Jutkiewicz EM. Biasing G βγ Downstream Signaling with Gallein Inhibits Development of Morphine Tolerance and Potentiates Morphine-Induced Nociception in a Tolerant State. Mol Pharmacol 2024; 106:47-55. [PMID: 38769020 PMCID: PMC11187686 DOI: 10.1124/molpharm.124.000875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/03/2024] [Accepted: 05/09/2024] [Indexed: 05/22/2024] Open
Abstract
Opioid analgesics are widely used as a treatment option for pain management and relief. However, the misuse of opioid analgesics has contributed to the current opioid epidemic in the United States. Prescribed opioids such as morphine, codeine, oxycodone, and fentanyl are mu-opioid receptor (MOR) agonists primarily used in the clinic to treat pain or during medical procedures, but development of tolerance limits their utility for treatment of chronic pain. Here we explored the effects of biasing Gβγ signaling on tolerance development after chronic morphine treatment in vivo. We hypothesized that biasing Gβγ signaling with gallein could prevent activation of regulatory signaling pathways that result in tolerance to antinociceptive effects of MOR agonists. Gallein has been shown to bind to Gβγ and inhibit interactions of Gβγ with phospholipase-Cβ3 (PLCβ3) or G-protein-coupled receptor kinase 2 (GRK2) but not G-protein inwardly rectifying potassium (GIRK) channels. In mice, morphine-induced antinociception was evaluated in the 55°C warm water tail withdrawal assay. We used two paradigms for gallein treatment: administration during and after three times-daily morphine administration. Our results show that gallein cotreatment during repeated administration of morphine decreased opioid tolerance development and that gallein treatment in an opioid-tolerant state enhanced the potency of morphine. Mechanistically, our data suggest that PLCβ3 is necessary for potentiating effects of gallein in an opioid-tolerant state but not in preventing the development of tolerance. These studies demonstrate that small molecules that target Gβγ signaling could reduce the need for large doses of opioid analgesics to treat pain by producing an opioid-sparing effect. SIGNIFICANCE STATEMENT: Biasing Gβγ signaling prevents tolerance to repeated morphine administration in vivo and potentiates the antinociceptive effects of morphine in an opioid-tolerant state. Mechanistically, phospholipase-Cβ is necessary for potentiating effects of gallein in an opioid-tolerant state but not in preventing the development of tolerance. This study identifies a novel treatment strategy to decrease the development of tolerance to the analgesic effects of mu-opioid receptor agonists, which are necessary to improve pain treatment and decrease the incidence of opioid use disorder.
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Affiliation(s)
- Gissell A Sanchez
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
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Chen H, Wang X, Cheng H, Deng Y, Chen J, Wang B. CircRNA circRREB1 promotes tumorigenesis and progression of breast cancer by activating Erk1/2 signaling through interacting with GNB4. Heliyon 2024; 10:e28785. [PMID: 38617926 PMCID: PMC11015410 DOI: 10.1016/j.heliyon.2024.e28785] [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: 06/15/2023] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024] Open
Abstract
Current investigations have illuminated the essential roles played by circular RNAs (circRNAs) in driving breast cancer (BC) tumorigenesis. However, the functional implications and molecular underpinnings of most circRNAs in BC are not well characterized. Here, Circular RNA (circRNA) expression profiles were analyzed in four surgically resected BC cases along with adjacent non-cancerous tissues applying RNA microarray analysis. The levels and prognostic implications of circRREB1 in BC were subjected to quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH). Experimental manipulation of circRREB1 levels in both in vivo and in vitro settings further delineated its role in BC cell growth, invasion, and metastasis. The mechanical verification of circRREB1's interaction with GNB4 was established through RNA pull-down, mass spectrometry, Western blot analysis, RNA immunoprecipitation assays (RIP), fluorescence ISH (FISH), and rescue experiments. We found that circRREB1 exhibited significant upregulation in BC tissues and cells, implicating its association with an unfavorable prognosis in BC patients. CircRREB1 knockdown elicited anti-proliferative, anti-migratory, anti-invasive, and pro-apoptotic effects in BC cells, whereas its upregulation exerted opposing influences. Follow-up mechanistic examinations suggested that circRREB1 might interact with GNB4 directly, inducing the activation of Erk1/2 signaling and driving BC progression. Our findings collectively indicate that the interplay of circRREB1 with GNB4 promotes Erk1/2 signaling, thereby fostering BC progression, and positioning circRREB1 as a candidate therapeutic target for intervention in BC.
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Affiliation(s)
- Hong Chen
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Xiaosong Wang
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Hang Cheng
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Yumei Deng
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Junxia Chen
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Bin Wang
- Department of Oncology, The Seventh People's Hospital of Chongqing (Affiliated Central Hospital of Chongqing University of Technology), Chongqing 400054, China
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Zhu H, Liu X, Wang X, Li Y, Ma F, Tan B, Zhou P, Fu F, Su R. Gβγ subunit inhibitor decreases DOM-induced head twitch response via the PLCβ/IP3/Ca 2+/ERK and cAMP signaling pathways. Eur J Pharmacol 2023; 957:176038. [PMID: 37657742 DOI: 10.1016/j.ejphar.2023.176038] [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: 03/12/2023] [Revised: 08/17/2023] [Accepted: 08/30/2023] [Indexed: 09/03/2023]
Abstract
AIMS (-)-2,5-dimethoxy-4-methylamphetamine (DOM) induces the head-twitch response (HTR) primarily by activating the serotonin 5-hydroxytryptamine 2A receptor (5-HT2A receptor) in mice. However, the mechanisms underlying 5-HT2A receptor activation and the HTR remain elusive. Gβγ subunits are a potential treatment target in numerous diseases. The present study investigated the mechanism whereby Gβγ subunits influence DOM-induced HTR. MAIN METHODS The effects of the Gβγ inhibitor 3',4',5',6'-tetrahydroxyspiro[2-benzofuran-3,9'-xanthene]-1-one (gallein) and antagonistic peptide βARKct (β-adrenergic receptor kinase C-terminal fragment) on DOM-induced HTR were studied via an HTR test. The activation of the phospholipase C β (PLCβ)/inositol triphosphate (IP3)/calcium (Ca2+) signaling pathway and extracellular signal-regulated kinase (ERK) following Gβγ subunit inhibition was detected by western blotting, Homogeneous Time-Resolved Fluorescence (HTRF) inositol phosphate (IP1) assay and Fluorometric Imaging Plate Reader (FLIPR) calcium 6 assay. The Gβγ subunit-mediated regulation of cyclic adenosine monophosphate (cAMP) was assessed via a GloSensor™ cAMP assay. KEY FINDINGS The Gβγ subunit inhibitors gallein and βARKct reduced DOM-induced HTR in C57BL/6J mice. Like the 5-HT2A receptor-selective antagonist (R)-[2,3-di(methoxy)phenyl]-[1-[2-(4-fluorophenyl)ethyl]piperidin-4-yl]methanol (M100907), gallein inhibited PLCβ phosphorylation (pPLCβ), IP1 production, Ca2+ transients, ERK1/2 phosphorylation (pERK1/2) and cAMP accumulation induced by DOM in human embryonic kidney (HEK) 293T cells stably or transiently transfected with the human 5-HT2A receptor. Moreover, PLCβ protein inhibitor 1-[6-[[(8R,9S,13S,14S,17S)-3-methoxy-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta[a]phenanthren-17-yl]amino]hexyl]pyrrole-2,5-dione (U73122) (10 nmol/mouse), intracellular Ca2+ blocker 6-[6-[6-[5-acetamido-4,6-dihydroxy-2-(sulfooxymethyl)oxan-3-yl]oxy-2-carboxy-4-hydroxy-5-sulfooxyoxan-3-yl]oxy-2-(hydroxymethyl)-5-(sulfoamino)-4-sulfooxyoxan-3-yl]oxy-3,4-dihydroxy-5-sulfooxyoxane-2-carboxylic acid (heparin) (5 nmol/mouse), L-type Ca2+ channel blocker 3-O-(2-methoxyethyl) 5-O-propan-2-yl 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (nimodipine) (4 mg/kg), mitogen extracellular regulating kinase 1/2 (MEK1/2) inhibitor (Z)-3-amino-3-(4-aminophenyl)sulfanyl-2-[2-(trifluoromethyl)phenyl]prop-2-enenitrile (SL327) (30 mg/kg), and Gαs protein selective antagonist 4,4',4″,4‴-(Carbonylbis-(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakisbenzene-1,3-disulfonic acid (NF449) (10 nmol/mouse) reduced DOM-induced HTR in C57BL/6J mice. SIGNIFICANCE The Gβγ subunits potentially mediate the HTR after 5-HT2A receptor activation via the PLCβ/IP3/Ca2+/ERK1/2 and cAMP signaling pathways. Inhibitors targeting the Gβγ subunits potentially inhibit the hallucinogenic effects of 5-HT2A receptor agonists.
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Affiliation(s)
- Huili Zhu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China; School of Pharmacy, Yantai University, Yantai, 264005, China
| | - Xiaoqian Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Xiaoxuan Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Yulei Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Fang Ma
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Bo Tan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Peilan Zhou
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
| | - Fenghua Fu
- School of Pharmacy, Yantai University, Yantai, 264005, China
| | - Ruibin Su
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
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Cooke M, Zhang S, Cornejo Maciel F, Kazanietz MG. Gi/o GPCRs drive the formation of actin-rich tunneling nanotubes in cancer cells via a Gβγ/PKCα/FARP1/Cdc42 axis. J Biol Chem 2023; 299:104983. [PMID: 37390986 PMCID: PMC10374973 DOI: 10.1016/j.jbc.2023.104983] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/02/2023] Open
Abstract
The functional association between stimulation of G-protein-coupled receptors (GPCRs) by eicosanoids and actin cytoskeleton reorganization remains largely unexplored. Using a model of human adrenocortical cancer cells, here we established that activation of the GPCR OXER1 by its natural agonist, the eicosanoid 5-oxo-eicosatetraenoic acid, leads to the formation of filopodia-like elongated projections connecting adjacent cells, known as tunneling nanotube (TNT)-like structures. This effect is reduced by pertussis toxin and GUE1654, a biased antagonist for the Gβγ pathway downstream of OXER1 activation. We also observed pertussis toxin-dependent TNT biogenesis in response to lysophosphatidic acid, indicative of a general response driven by Gi/o-coupled GPCRs. TNT generation by either 5-oxo-eicosatetraenoic acid or lysophosphatidic acid is partially dependent on the transactivation of the epidermal growth factor receptor and impaired by phosphoinositide 3-kinase inhibition. Subsequent signaling analysis reveals a strict requirement of phospholipase C β3 and its downstream effector protein kinase Cα. Consistent with the established role of Rho small GTPases in the formation of actin-rich projecting structures, we identified the phosphoinositide 3-kinase-regulated guanine nucleotide exchange factor FARP1 as a GPCR effector essential for TNT formation, acting via Cdc42. Altogether, our study pioneers a link between Gi/o-coupled GPCRs and TNT development and sheds light into the intricate signaling pathways governing the generation of specialized actin-rich elongated structures in response to bioactive signaling lipids.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Suli Zhang
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Fabiana Cornejo Maciel
- Departament of Human Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina; INBIOMED, CONICET, Buenos Aires, Argentina
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Antonino M, Marmo P, Freites CL, Quassollo GE, Sánchez MF, Lorenzo A, Bignante EA. Aβ Assemblies Promote Amyloidogenic Processing of APP and Intracellular Accumulation of Aβ42 Through Go/Gβγ Signaling. Front Cell Dev Biol 2022; 10:852738. [PMID: 35445022 PMCID: PMC9013780 DOI: 10.3389/fcell.2022.852738] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/07/2022] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the deposition of aggregated species of amyloid beta (Aβ) in the brain, which leads to progressive cognitive deficits and dementia. Aβ is generated by the successive cleavage of the amyloid precursor protein (APP), first by β-site APP cleaving enzyme 1 (BACE1) and subsequently by the γ-secretase complex. Those conditions which enhace or reduce its clearance predispose to Aβ aggregation and the development of AD. In vitro studies have demonstrated that Aβ assemblies spark a feed-forward loop heightening Aβ production. However, the underlying mechanism remains unknown. Here, we show that oligomers and fibrils of Aβ enhance colocalization and physical interaction of APP and BACE1 in recycling endosomes of human neurons derived from induced pluripotent stem cells and other cell types, which leads to exacerbated amyloidogenic processing of APP and intracellular accumulation of Aβ42. In cells that are overexpressing the mutant forms of APP which are unable to bind Aβ or to activate Go protein, we have found that treatment with aggregated Aβ fails to increase colocalization of APP with BACE1 indicating that Aβ-APP/Go signaling is involved in this process. Moreover, inhibition of Gβγ subunit signaling with βARKct or gallein prevents Aβ-dependent interaction of APP and BACE1 in endosomes, β-processing of APP, and intracellular accumulation of Aβ42. Collectively, our findings uncover a signaling mechanism leading to a feed-forward loop of amyloidogenesis that might contribute to Aβ pathology in the early stages of AD and suggest that gallein could have therapeutic potential.
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Affiliation(s)
- Magdalena Antonino
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paula Marmo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Carlos Leandro Freites
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | | | - Alfredo Lorenzo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
- *Correspondence: Elena Anahi Bignante, ; Alfredo Lorenzo,
| | - Elena Anahi Bignante
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto Universitario de Ciencias Biomédicas de Córdoba (IUCBC), Córdoba, Argentina
- *Correspondence: Elena Anahi Bignante, ; Alfredo Lorenzo,
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Knight KM, Ghosh S, Campbell SL, Lefevre TJ, Olsen RHJ, Smrcka AV, Valentin NH, Yin G, Vaidehi N, Dohlman HG. A universal allosteric mechanism for G protein activation. Mol Cell 2021; 81:1384-1396.e6. [PMID: 33636126 DOI: 10.1016/j.molcel.2021.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 12/01/2020] [Accepted: 01/29/2021] [Indexed: 12/11/2022]
Abstract
G proteins play a central role in signal transduction and pharmacology. Signaling is initiated by cell-surface receptors, which promote guanosine triphosphate (GTP) binding and dissociation of Gα from the Gβγ subunits. Structural studies have revealed the molecular basis of subunit association with receptors, RGS proteins, and downstream effectors. In contrast, the mechanism of subunit dissociation is poorly understood. We use cell signaling assays, molecular dynamics (MD) simulations, and biochemistry and structural analyses to identify a conserved network of amino acids that dictates subunit release. In the presence of the terminal phosphate of GTP, a glycine forms a polar network with an arginine and glutamate, putting torsional strain on the subunit binding interface. This "G-R-E motif" secures GTP and, through an allosteric link, discharges the Gβγ dimer. Replacement of network residues prevents subunit dissociation regardless of agonist or GTP binding. These findings reveal the molecular basis of the final committed step of G protein activation.
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Affiliation(s)
- Kevin M Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Soumadwip Ghosh
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tyler J Lefevre
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Reid H J Olsen
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Natalie H Valentin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Guowei Yin
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Abstract
G protein-coupled receptors (GPCRs) are the largest class of drug targets, largely owing to their druggability, diversity and physiological efficacy. Many drugs selectively target specific subtypes of GPCRs, but high specificity for individual GPCRs may not be desirable in complex multifactorial disease states in which multiple receptors may be involved. One approach is to target G protein subunits rather than the GPCRs directly. This approach has the potential to achieve broad efficacy by blocking pathways shared by multiple GPCRs. Additionally, because many GPCRs couple to multiple G protein signalling pathways, blocking specific G protein subunits can 'bias' GPCR signals by inhibiting only a subset of these signals. Molecules that target G protein α or βγ-subunits have been developed and show strong efficacy in multiple preclinical disease models and biased inhibition of G protein signalling. In this Review, we discuss the development and characterization of G protein α and βγ-subunit ligands and the preclinical evidence that this exciting new approach has potential for therapeutic efficacy in a number of indications, such as pain, thrombosis, asthma and heart failure.
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Sánchez-Zavaleta R, Cortés H, Avalos-Fuentes JA, García U, Segovia Vila J, Erlij D, Florán B. Presynaptic cannabinoid CB2 receptors modulate [ 3 H]-Glutamate release at subthalamo-nigral terminals of the rat. Synapse 2018; 72:e22061. [PMID: 30022523 DOI: 10.1002/syn.22061] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/08/2022]
Abstract
Recent studies suggested the expression of CB2 receptors in neurons of the CNS, however, most of these studies have only explored one aspect of the receptors, i.e., expression of protein, messenger RNA, or functional response, and more complete studies appear to be needed to establish adequately their role in the neuronal function. Electron microscopy studies showed the presence of CB2r in asymmetric terminals of the substantia nigra pars reticulata (SNr), and its mRNA appeared is expressed in the subthalamic nucleus. Here, we explore the expression, source, and functional effects of such receptors by different experimental approaches. Through PCR and immunochemistry, we showed mRNA and protein for CB2rs in slices and primary neuronal cultures from subthalamus. GW833972A, GW405833, and JHW 133, three CB2r agonists dose-dependent inhibited K+ -induced [3 H]-Glutamate release in slices of SNr, and the two antagonist/inverse agonists, JTE-907 and AM630, but not AM281, a CB1r antagonist, prevented GW833972A effect. Subthalamus lesions with kainic acid prevented GW833972A inhibition on release and decreased CB2r protein in nigral synaptosomes, thus nigral CB2rs originate in subthalamus. Inhibition of [3 H]-Glutamate release was PTX- and gallein-sensitive, suggesting a Giβγ -mediated effect. P/Q Ca2+ -type channel blocker, ω-Agatoxin-TK, also inhibited the [3 H]-Glutamate release, this effect was occluded with GW833972A inhibition, indicating that the βγ subunit effect is exerted on Ca2+ channel activity. Finally, microinjections of GW833972A in SNr induced contralateral turning. Our data showed that presynaptic CB2rs inhibit [3 H]-Glutamate release in subthalamo-nigral terminals by P/Q-channels modulation through the Giβγ subunit and suggested their participation in motor behavior.
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Affiliation(s)
- Rodolfo Sánchez-Zavaleta
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, México
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Ubaldo García
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - José Segovia Vila
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - David Erlij
- Department of Physiology, SUNY Downstate Medical Center, Brooklyn, New York
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
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Lavenus S, Simard É, Besserer-Offroy É, Froehlich U, Leduc R, Grandbois M. Label-free cell signaling pathway deconvolution of angiotensin type 1 receptor reveals time-resolved G-protein activity and distinct AngII and AngIIIIV responses. Pharmacol Res 2018; 136:108-120. [PMID: 29959993 DOI: 10.1016/j.phrs.2018.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/18/2018] [Accepted: 06/26/2018] [Indexed: 01/14/2023]
Abstract
Angiotensin II (AngII) type 1 receptor (AT1R) is a G protein-coupled receptor known for its role in numerous physiological processes and its implication in many vascular diseases. Its functions are mediated through G protein dependent and independent signaling pathways. AT1R has several endogenous peptidic agonists, all derived from angiotensinogen, as well as several synthetic ligands known to elicit biased signaling responses. Here, surface plasmon resonance (SPR) was used as a cell-based and label-free technique to quantify, in real time, the response of HEK293 cells stably expressing the human AT1R. The goal was to take advantage of the integrative nature of this assay to identify specific signaling pathways in the features of the response profiles generated by numerous endogenous and synthetic ligands of AT1R. First, we assessed the contributions of Gq, G12/13, Gi, Gβγ, ERK1/2 and β-arrestins pathways in the cellular responses measured by SPR where Gq, G12/Rho/ROCK together with β-arrestins and ERK1/2 were found to play significant roles. More specifically, we established a major role for G12 in the early events of the AT1R-dependent response, which was followed by a robust ERK1/2 component associated to the later phase of the signal. Interestingly, endogenous AT1R ligands (AngII, AngIII and AngIV) exhibited distinct responses signatures with a significant increase of the ERK1/2-like components for both AngIII and AngIV, which points toward possibly distinct physiological roles for the later. We also tested AT1R biased ligands, all of which affected both the early and later events. Our results support SPR-based integrative cellular assays as a powerful approach to delineate the contribution of specific signaling pathways for a given cell response and reveal response differences associated with ligands with distinct pharmacological properties.
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Affiliation(s)
- Sandrine Lavenus
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Élie Simard
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Élie Besserer-Offroy
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Ulrike Froehlich
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Michel Grandbois
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
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11
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Jijón-Lorenzo R, Caballero-Florán IH, Recillas-Morales S, Cortés H, Avalos-Fuentes JA, Paz-Bermúdez FJ, Erlij D, Florán B. Presynaptic Dopamine D2 Receptors Modulate [ 3H]GABA Release at StriatoPallidal Terminals via Activation of PLC → IP3 → Calcineurin and Inhibition of AC → cAMP → PKA Signaling Cascades. Neuroscience 2017; 372:74-86. [PMID: 29292080 DOI: 10.1016/j.neuroscience.2017.12.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/14/2017] [Accepted: 12/23/2017] [Indexed: 01/11/2023]
Abstract
Striatal dopamine D2 receptors activate the PLC → IP3 → Calcineurin-signaling pathway to modulate the neural excitability of En+ Medium-sized Spiny GABAergic neurons (MSN) through the regulation of L-type Ca2+ channels. Presynaptic dopaminergic D2 receptors modulate GABA release at striatopallidal terminals through L-type Ca2+ channels as well, but their signaling pathway is still undetermined. Since D2 receptors are Gi/o-coupled and negatively modulate adenylyl cyclase (AC), we investigated whether presynaptic D2 receptors modulate GABA release through the same signaling cascade that controls excitability in the striatum or by the inhibition of AC and decreased PKA activity. Activation of D2 receptors stimulated formation of [3H]IP1 and decreased Forskolin-stimulated [3H]cAMP accumulation in synaptosomes from rat Globus Pallidus. D2 receptor activation with Quinpirole in the presence of L 745,870 decreased, in a dose-dependent manner, K+-induced [3H]GABA release in pallidal slices. The effect was prevented by the pharmacological blockade of Gi/o βγ subunit effects with Gallein, PLC with U 73122, IP3 receptor activation with 4-APB, Calcineurin with FK506. In addition, when release was stimulated with Forskolin to activate AC, D2 receptors also decreased K+-induced [3H]GABA release, an effect occluded with the effect of the blockade of PKA with H89 or stimulation of release with the cAMP analog 8-Br-cAMP. These data indicate that D2 receptors modulate [3H]GABA release at striatopallidal terminals by activating the PLC → IP3 → Calcineurin-signaling cascade, the same one that modulates excitability in soma. Additionally, D2 receptors inhibit release when AC is active. Both mechanisms appear to converge to regulate the activity of presynaptic L-type Ca2+ channels.
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Affiliation(s)
- Rafael Jijón-Lorenzo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Isaac Hiram Caballero-Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | | | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, Mexico
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Francisco Javier Paz-Bermúdez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - David Erlij
- Department of Physiology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico.
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12
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Bignante EA, Ponce NE, Heredia F, Musso J, Krawczyk MC, Millán J, Pigino GF, Inestrosa NC, Boccia MM, Lorenzo A. APP/Go protein Gβγ-complex signaling mediates Aβ degeneration and cognitive impairment in Alzheimer's disease models. Neurobiol Aging 2017; 64:44-57. [PMID: 29331876 DOI: 10.1016/j.neurobiolaging.2017.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/05/2017] [Accepted: 12/10/2017] [Indexed: 11/15/2022]
Abstract
Deposition of amyloid-β (Aβ), the proteolytic product of the amyloid precursor protein (APP), might cause neurodegeneration and cognitive decline in Alzheimer's disease (AD). However, the direct involvement of APP in the mechanism of Aβ-induced degeneration in AD remains on debate. Here, we analyzed the interaction of APP with heterotrimeric Go protein in primary hippocampal cultures and found that Aβ deposition dramatically enhanced APP-Go protein interaction in dystrophic neurites. APP overexpression rendered neurons vulnerable to Aβ toxicity by a mechanism that required Go-Gβγ complex signaling and p38-mitogen-activated protein kinase activation. Gallein, a selective pharmacological inhibitor of Gβγ complex, inhibited Aβ-induced dendritic and axonal dystrophy, abnormal tau phosphorylation, synaptic loss, and neuronal cell death in hippocampal neurons expressing endogenous protein levels. In the 3xTg-AD mice, intrahippocampal application of gallein reversed memory impairment associated with early Aβ pathology. Our data provide further evidence for the involvement of APP/Go protein in Aβ-induced degeneration and reveal that Gβγ complex is a signaling target potentially relevant for developing therapies for halting Aβ degeneration in AD.
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Affiliation(s)
- Elena Anahi Bignante
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina; Instituto Universitario de Ciencias Biomédicas de Córdoda (IUCBC), Argentina
| | - Nicolás Eric Ponce
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Florencia Heredia
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juliana Musso
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María C Krawczyk
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Julieta Millán
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gustavo F Pigino
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Punta Arenas, Chile
| | - Mariano M Boccia
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alfredo Lorenzo
- Instituto de Investigación Médica "Mercedes y Martín Ferreyra", INIMEC-CONICET- Universidad Nacional de Córdoba, Córdoba, Argentina; Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
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13
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Intrinsic plasticity induced by group II metabotropic glutamate receptors via enhancement of high-threshold KV currents in sound localizing neurons. Neuroscience 2016; 324:177-90. [PMID: 26964678 DOI: 10.1016/j.neuroscience.2016.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/05/2016] [Accepted: 03/03/2016] [Indexed: 01/18/2023]
Abstract
Intrinsic plasticity has emerged as an important mechanism regulating neuronal excitability and output under physiological and pathological conditions. Here, we report a novel form of intrinsic plasticity. Using perforated patch clamp recordings, we examined the modulatory effects of group II metabotropic glutamate receptors (mGluR II) on voltage-gated potassium (KV) currents and the firing properties of neurons in the chicken nucleus laminaris (NL), the first central auditory station where interaural time cues are analyzed for sound localization. We found that activation of mGluR II by synthetic agonists resulted in a selective increase of the high-threshold KV currents. More importantly, synaptically released glutamate (with reuptake blocked) also enhanced the high-threshold KV currents. The enhancement was frequency-coding region dependent, being more pronounced in low-frequency neurons compared to middle- and high-frequency neurons. The intracellular mechanism involved the Gβγ signaling pathway associated with phospholipase C and protein kinase C. The modulation strengthened membrane outward rectification, sharpened action potentials, and improved the ability of NL neurons to follow high-frequency inputs. These data suggest that mGluR II provides a feedforward modulatory mechanism that may regulate temporal processing under the condition of heightened synaptic inputs.
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14
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Mu HN, Li Q, Pan CS, Liu YY, Yan L, Hu BH, Sun K, Chang X, Zhao XR, Fan JY, Han JY. Caffeic acid attenuates rat liver reperfusion injury through sirtuin 3-dependent regulation of mitochondrial respiratory chain. Free Radic Biol Med 2015; 85:237-49. [PMID: 25960048 DOI: 10.1016/j.freeradbiomed.2015.04.033] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/21/2015] [Accepted: 04/29/2015] [Indexed: 02/07/2023]
Abstract
Sirtuin 3 (Sirt3) plays critical roles in regulating mitochondrial oxidative metabolism. However, whether Sirt3 is involved in liver ischemia and reperfusion (I/R) injury remains elusive. Caffeic acid (CA) is a natural antioxidant derived from Salvia miltiorrhiza. Whether CA protects against liver I/R injury through regulating Sirt3 and the mitochondrial respiratory chain (MRC) is unclear. This study investigated the effect of CA on liver I/R injury, microcirculatory disturbance, and potential mechanisms, particularly focusing on Sirt3-dependent MRC. Liver I/R of male Sprague-Dawley rats was established by occlusion of portal area vessels for 30 min followed by 120 min of reperfusion. CA (15 mg/kg/h) was continuously infused via the femoral vein starting 30 min before ischemia. After I/R, Sirt3 expression, and MRC activity decreased, acetylation of NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 and succinate dehydrogenase complex, subunit A, flavoprotein variant provoked, and the liver microcirculatory disturbance and injury were observed. Treatment with CA attenuated liver injury, inhibited Sirt3 down-expression, and up-regulated MRC activity. CA attenuated rat liver microcirculatory disturbance and oxidative injury through regulation of Sirt3 and the mitochondrial respiratory chain.
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Affiliation(s)
- Hong-Na Mu
- Department of Integration of Chinese and Western Medicine, School of Basic Medical Sciences, Peking University, Beijing, China; Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Quan Li
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Chun-Shui Pan
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Yu-Ying Liu
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Li Yan
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Bai-He Hu
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Kai Sun
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Xin Chang
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Xin-Rong Zhao
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Jing-Yu Fan
- Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China
| | - Jing-Yan Han
- Department of Integration of Chinese and Western Medicine, School of Basic Medical Sciences, Peking University, Beijing, China; Tasly Microcirculation Research Center, Peking University Health Science Center, Beijing, China; Key Laboratory of Stasis and Phlegm of State Administration of Traditional Chinese Medicine, Beijing, China.
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15
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Inhibition of G-Protein βγ Signaling Decreases Levels of Messenger RNAs Encoding Proinflammatory Cytokines in T Cell Receptor-Stimulated CD4(+) T Helper Cells. J Mol Signal 2015; 10:1. [PMID: 27095999 PMCID: PMC4831316 DOI: 10.5334/1750-2187-10-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Inhibition of G-protein βγ (Gβγ) signaling was found previously to enhance T cell receptor (TCR)-stimulated increases in interleukin 2 (IL-2) mRNA in CD4+ T helper cells, suggesting that Gβγ might be a useful drug target for treating autoimmune diseases, as low dose IL-2 therapy can suppress autoimmune responses. Because IL-2 may counteract autoimmunity in part by shifting CD4+ T helper cells away from the Type 1 T helper cell (TH1) and TH17 subtypes towards the TH2 subtype, the purpose of this study was to determine if blocking Gβγ signaling affected the balance of TH1, TH17, and TH2 cytokine mRNAs produced by CD4+ T helper cells. Methods: Gallein, a small molecule inhibitor of Gβγ, and siRNA-mediated silencing of the G-protein β1 subunit (Gβ1) were used to test the effect of blocking Gβγ on mRNA levels of cytokines in primary human TCR-stimulated CD4+ T helper cells. Results: Gallein and Gβ1 siRNA decreased interferon-γ (IFN-γ) and IL-17A mRNA levels in TCR-stimulated CD4+ T cells grown under TH1-promoting conditions. Inhibiting Gβγ also decreased mRNA levels of STAT4, which plays a positive role in TH1 differentiation and IL-17A production. Moreover, mRNA levels of the STAT4-regulated TH1-associated proteins, IL-18 receptor β chain (IL-18Rβ), mitogen-activated protein kinase kinase kinase 8 (MAP3K8), lymphocyte activation gene 3 (LAG-3), natural killer cell group 7 sequence (NKG7), and oncostatin M (OSM) were also decreased upon Gβγ inhibition. Gallein also increased IL-4, IL-5, IL-9, and IL-13 mRNA levels in TCR-stimulated memory CD4+ T cells grown in TH2-promoting conditions. Conclusions: Inhibiting Gβγ to produce these shifts in cytokine mRNA production might be beneficial for patients with autoimmune diseases such as rheumatoid arthritis (RA), Crohn’s disease (CD), psoriasis, multiple sclerosis (MS), and Hashimoto’s thyroiditis (HT), in which both IFN-γ and IL-17A are elevated.
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16
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Aznar N, Midde KK, Dunkel Y, Lopez-Sanchez I, Pavlova Y, Marivin A, Barbazán J, Murray F, Nitsche U, Janssen KP, Willert K, Goel A, Abal M, Garcia-Marcos M, Ghosh P. Daple is a novel non-receptor GEF required for trimeric G protein activation in Wnt signaling. eLife 2015; 4:e07091. [PMID: 26126266 PMCID: PMC4484057 DOI: 10.7554/elife.07091] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/01/2015] [Indexed: 12/17/2022] Open
Abstract
Wnt signaling is essential for tissue homeostasis and its dysregulation causes cancer. Wnt ligands trigger signaling by activating Frizzled receptors (FZDRs), which belong to the G-protein coupled receptor superfamily. However, the mechanisms of G protein activation in Wnt signaling remain controversial. In this study, we demonstrate that FZDRs activate G proteins and trigger non-canonical Wnt signaling via the Dishevelled-binding protein, Daple. Daple contains a Gα-binding and activating (GBA) motif, which activates Gαi proteins and an adjacent domain that directly binds FZDRs, thereby linking Wnt stimulation to G protein activation. This triggers non-canonical Wnt responses, that is, suppresses the β-catenin/TCF/LEF pathway and tumorigenesis, but enhances PI3K-Akt and Rac1 signals and tumor cell invasiveness. In colorectal cancers, Daple is suppressed during adenoma-to-carcinoma transformation and expressed later in metastasized tumor cells. Thus, Daple activates Gαi and enhances non-canonical Wnt signaling by FZDRs, and its dysregulation can impact both tumor initiation and progression to metastasis.
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Affiliation(s)
- Nicolas Aznar
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Krishna K Midde
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Ying Dunkel
- Department of Medicine, University of California, San Diego, San Diego, United States
| | | | - Yelena Pavlova
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Jorge Barbazán
- Translational Medical Oncology Laboratory, Health Research Institute of Santiago, Servizo Galego de Saúde, Santiago de Compostela, Spain
| | - Fiona Murray
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Ulrich Nitsche
- Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Klaus-Peter Janssen
- Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Karl Willert
- Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, California, United States
| | - Ajay Goel
- Division of Gastroenterology, Department of Internal Medicine and Charles A Sammons Cancer Center and Baylor Research Institute, Baylor University Medical Center, Dallas, Texas, United States
| | - Miguel Abal
- Translational Medical Oncology Laboratory, Health Research Institute of Santiago, Servizo Galego de Saúde, Santiago de Compostela, Spain
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego, San Diego, United States
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17
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Yost EA, Hynes TR, Hartle CM, Ott BJ, Berlot CH. Inhibition of G-protein βγ signaling enhances T cell receptor-stimulated interleukin 2 transcription in CD4+ T helper cells. PLoS One 2015; 10:e0116575. [PMID: 25629163 PMCID: PMC4309538 DOI: 10.1371/journal.pone.0116575] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/10/2014] [Indexed: 01/23/2023] Open
Abstract
G-protein-coupled receptor (GPCR) signaling modulates the expression of cytokines that are drug targets for immune disorders. However, although GPCRs are common targets for other diseases, there are few GPCR-based pharmaceuticals for inflammation. The purpose of this study was to determine whether targeting G-protein βγ (Gβγ) complexes could provide a useful new approach for modulating interleukin 2 (IL-2) levels in CD4+ T helper cells. Gallein, a small molecule inhibitor of Gβγ, increased levels of T cell receptor (TCR)-stimulated IL-2 mRNA in primary human naïve and memory CD4+ T helper cells and in Jurkat human CD4+ leukemia T cells. Gβ1 and Gβ2 mRNA accounted for >99% of Gβ mRNA, and small interfering RNA (siRNA)-mediated silencing of Gβ1 but not Gβ2 enhanced TCR-stimulated IL-2 mRNA increases. Blocking Gβγ enhanced TCR-stimulated increases in IL-2 transcription without affecting IL-2 mRNA stability. Blocking Gβγ also enhanced TCR-stimulated increases in nuclear localization of nuclear factor of activated T cells 1 (NFAT1), NFAT transcriptional activity, and levels of intracellular Ca2+. Potentiation of IL-2 transcription required continuous Gβγ inhibition during at least two days of TCR stimulation, suggesting that induction or repression of additional signaling proteins during T cell activation and differentiation might be involved. The potentiation of TCR-stimulated IL-2 transcription that results from blocking Gβγ in CD4+ T helper cells could have applications for autoimmune diseases.
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Affiliation(s)
- Evan A. Yost
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, 17822-2623, United States of America
| | - Thomas R. Hynes
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, 17822-2623, United States of America
| | - Cassandra M. Hartle
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, 17822-2623, United States of America
| | - Braden J. Ott
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, 17822-2623, United States of America
| | - Catherine H. Berlot
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, 17822-2623, United States of America
- * E-mail:
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18
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Surve CR, Lehmann D, Smrcka AV. A chemical biology approach demonstrates G protein βγ subunits are sufficient to mediate directional neutrophil chemotaxis. J Biol Chem 2014; 289:17791-801. [PMID: 24808183 DOI: 10.1074/jbc.m114.576827] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Our laboratory has identified a number of small molecules that bind to G protein βγ subunits (Gβγ) by competing for peptide binding to the Gβγ "hot spot." M119/Gallein were identified as inhibitors of Gβγ subunit signaling. Here we examine the activity of another molecule identified in this screen, 12155, which we show that in contrast to M119/Gallein had no effect on Gβγ-mediated phospholipase C or phosphoinositide 3-kinase (PI3K) γ activation in vitro. Also in direct contrast to M119/Gallein, 12155 caused receptor-independent Ca(2+) release, and activated other downstream targets of Gβγ including extracellular signal regulated kinase (ERK), protein kinase B (Akt) in HL60 cells differentiated to neutrophils. We show that 12155 releases Gβγ in vitro from Gαi1β1γ2 heterotrimers by causing its dissociation from GαGDP without inducing nucleotide exchange in the Gα subunit. We used this novel probe to examine the hypothesis that Gβγ release is sufficient to direct chemotaxis of neutrophils in the absence of receptor or G protein α subunit activation. 12155 directed chemotaxis of HL60 cells and primary neutrophils in a transwell migration assay with responses similar to those seen for the natural chemotactic peptide n-formyl-Met-Leu-Phe. These data indicate that release of free Gβγ is sufficient to drive directional chemotaxis in a G protein-coupled receptor signaling-independent manner.
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Affiliation(s)
| | - David Lehmann
- Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Alan V Smrcka
- From the Departments of Biochemistry and Biophysics and Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
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19
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Inhibition of Gβγ-subunit signaling potentiates morphine-induced antinociception but not respiratory depression, constipation, locomotion, and reward. Behav Pharmacol 2013; 24:144-52. [PMID: 23412114 DOI: 10.1097/fbp.0b013e32835f3d2f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Inhibition of Gβγ-subunit signaling to phospholipase C β3 has been shown to potentiate morphine-mediated antinociception while attenuating the development of tolerance and dependence in mice. The objective of this study was to determine the effect of Gβγ-subunit inhibition on antinociception and other pharmacological effects, such as respiratory depression, constipation, and hyperlocomotion, mediated by the μ-opioid receptor. The Gβγ-subunit inhibitor, gallein, was administered to C57BL/6J mice by intraperitoneal injection before morphine, and data were compared with mice treated with vehicle, morphine, or gallein alone. Morphine-induced antinociception was measured using the 55°C warm-water tail-withdrawal test. Pretreatment with gallein produced a dose-dependent potentiation of morphine-mediated antinociception, producing up to a 10-fold leftward shift in the morphine dose-response curve and extending the duration of antinociception induced by a single dose of morphine. Gallein pretreatment also prevented acute antinociceptive tolerance induced by morphine. In contrast, the dose-dependent respiratory depression and hyperlocomotion induced by morphine were not potentiated by gallein pretreatment. Similarly, gallein pretreatment did not potentiate morphine-conditioned place preference responses or morphine-induced constipation, as measured as a reduction in excreta. These results suggest that selectively inhibiting Gβγ-mediated signaling may selectively increase μ-opioid receptor-mediated antinociception without matching increases in adverse physiological effects.
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Ghanemi A. Targeting G protein coupled receptor-related pathways as emerging molecular therapies. Saudi Pharm J 2013; 23:115-29. [PMID: 25972730 PMCID: PMC4420995 DOI: 10.1016/j.jsps.2013.07.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/29/2013] [Indexed: 12/20/2022] Open
Abstract
G protein coupled receptors (GPCRs) represent the most important targets in modern pharmacology because of the different functions they mediate, especially within brain and peripheral nervous system, and also because of their functional and stereochemical properties. In this paper, we illustrate, via a variety of examples, novel advances about the GPCR-related molecules that have been shown to play diverse roles in GPCR pathways and in pathophysiological phenomena. We have exemplified how those GPCRs’ pathways are, or might constitute, potential targets for different drugs either to stimulate, modify, regulate or inhibit the cellular mechanisms that are hypothesized to govern some pathologic, physiologic, biologic and cellular or molecular aspects both in vivo and in vitro. Therefore, influencing such pathways will, undoubtedly, lead to different therapeutical applications based on the related pharmacological implications. Furthermore, such new properties can be applied in different fields. In addition to offering fruitful directions for future researches, we hope the reviewed data, together with the elements found within the cited references, will inspire clinicians and researchers devoted to the studies on GPCR’s properties.
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Affiliation(s)
- Abdelaziz Ghanemi
- Department of Pharmacology, China Pharmaceutical University, Nanjing 210009, China
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Differential regulation of chemotaxis: Role of Gβγ in chemokine receptor-induced cell migration. Cell Signal 2013; 25:729-35. [DOI: 10.1016/j.cellsig.2012.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 01/17/2023]
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Shi J, Ju M, Large WA, Albert AP. Pharmacological profile of phosphatidylinositol 3-kinases and related phosphatidylinositols mediating endothelin(A) receptor-operated native TRPC channels in rabbit coronary artery myocytes. Br J Pharmacol 2012; 166:2161-75. [PMID: 22404177 PMCID: PMC3402779 DOI: 10.1111/j.1476-5381.2012.01937.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/27/2012] [Accepted: 02/20/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Endothelin(A) (ET(A) ) receptor-operated canonical transient receptor potential (TRPC) channels mediate Ca²⁺ influx pathways, which are important in coronary artery function. Biochemical pathways linking ET(A) receptor stimulation to TRPC channel opening are unknown. We investigated the involvement of phosphatidylinositol 3-kinases (PI3K) in ET(A) receptor activation of native heteromeric TRPC1/C5/C6 and TRPC3/C7 channels in rabbit coronary artery vascular smooth muscle cells (VSMCs). EXPERIMENTAL APPROACH A pharmacological profile of PI3K was created by studying the effect of pan-PI3K, pan-Class I PI3K and Class I PI3K isoform-selective inhibitors on ET(A) receptor-evoked single TRPC1/C5/C6 and TRPC3/C7 channel activities in cell-attached patches from rabbit freshly isolated coronary artery VSMCs. The action of phosphatidylinositol 3-phosphate- [PI(3)P], 4-phosphate- [PI(4)P] and 5-phosphate- [PI(5)P] containing molecules involved in PI3K-mediated reactions were studied in inside-out patches. Expression of PI3K family members in coronary artery tissue lysates were analysed using quantitative PCR. KEY RESULTS ET(A) receptor-operated TRPC1/C5/C6 and TRPC3/C7 channel activities were inhibited by wortmannin. However, ZSTK474 and AS252424 reduced ET(A) receptor-evoked TRPC1/C5/C6 channel activity but potentiated TRPC3/C7 channel activity. All the PI(3)P-, PI(4)P- and PI(5)P-containing molecules tested induced TRPC1/C5/C6 channel activation, whereas only PI(3)P stimulated TRPC3/C7 channels. CONCLUSIONS AND IMPLICATIONS ET(A) receptor-operated native TRPC1/C5/C6 and TRPC3/C7 channel activities are likely to be mediated by Class I PI3Kγ and Class II/III PI3K isoforms, respectively. ET(A) receptor-evoked and constitutively active PI3Kγ-mediated pathways inhibit TRPC3/C7 channel activation. PI3K-mediated pathways are novel regulators of native TRPC channels in VSMCs, and these signalling cascades are potential pharmacological targets for coronary artery disease.
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Affiliation(s)
- J Shi
- Pharmacology & Cell Physiology, Division of Biomedical Sciences, St. George's, University of London, London, UK
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Lin Y, Smrcka AV. Understanding molecular recognition by G protein βγ subunits on the path to pharmacological targeting. Mol Pharmacol 2011; 80:551-7. [PMID: 21737569 DOI: 10.1124/mol.111.073072] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterotrimeric G proteins, composed of Gα and Gβγ subunits, transduce extracellular signals via G-protein-coupled receptors to modulate many important intracellular responses. The Gβγ subunits hold a central position in this signaling system and have been implicated in multiple aspects of physiology and the pathophysiology of disease. The Gβ subunit belongs to a large family of WD40 repeat proteins with a circular β-bladed propeller structure. This structure allows Gβγ to interact with a broad range of proteins to play diverse roles. How Gβγ interacts with and regulates such a wide variety of partners yet maintains specificity is an interesting problem in protein-protein molecular recognition in signal transduction, where signal transfer by proteins is often driven by modular conserved recognition motifs. Evidence has accumulated that one mechanism for Gβγ multitarget recognition is through an intrinsically flexible protein surface or "hot spot" that accommodates multiple modes of binding. Because each target has a unique recognition mode for Gβγ subunits, it suggests that these interactions could be selectively manipulated with small molecules, which could have significant therapeutic potential.
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Affiliation(s)
- Yuan Lin
- Department of Pharmacology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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