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Zhang XH, Shen CL, Wang XY, Xiong WF, Shang X, Tang LY, Zhang HX, Wan YH, Wu YB, Fei J, Yi QZ, Wang ZG. Increased Anxiety-like Behaviors in Adhesion G protein-coupled receptor A1 -/- Male But Not Female Mice are Attributable to Elevated Neuron Dendritic Density, Upregulated Postsynaptic Density Protein 95 Expression, and Abnormal Activation of the Phosphatidylinositol 3 Kinase/Protein Kinase B/Glycogen Synthase Kinase-3 and Methyl Ethyl Ketone/Extracellular Signal Regulated Kinase Pathways. Neuroscience 2022; 503:131-145. [PMID: 36115515 DOI: 10.1016/j.neuroscience.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/19/2022]
Abstract
Adhesion G protein-coupled receptor A1 (ADGRA1) belongs to the G protein-coupled receptor (GPCR) family, and its physiological function remains largely unknown. We found that Adgra1 is highly and exclusively expressed in the brain, suggesting that Adgra1 may be involved in the regulation of neurological behaviors including anxiety, depression, learning and memory. To this end, we comprehensively analyzed the potential role of ADGRA1 in the neurobehaviors of mice by comparing Adgra1-/- and their wild-type (wt) littermates. We found that Adgra1-/- male but not female mice exhibited elevated anxiety levels in the open field, elevated plus maze, and light-dark box tests, with normal depression levels in the tail-suspension and forced-swim tests, and comparable learning and memory abilities in the Morris water maze, Y maze, fear condition, and step-down avoidance tests. Further studies showed that ADGRA1 deficiency resulted in higher dendritic branching complexity and spine density as evidenced by elevated expression levels of SYN and PSD95 in amygdalae-of male mice. Finally, we found that PI3K/AKT/GSK-3β and MEK/ERK in amygdalae of Adgra1-deficient male mice were aberrantly activated when compared to wt male mice. Together, our findings reveal an important suppressive role of ADGRA1 in anxiety control and synaptic function by regulating the PI3K/AKT/GSK-3β and MEK/ERK pathways in amygdalae of male mice, implicating a potential, therapeutic application in novel anti-anxiety drug development.
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Affiliation(s)
- Xiao-Hong Zhang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Chun-Ling Shen
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Xi-Yi Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China; Department of Obstetrics and Gynecology, Tang-Du Hospital Affiliated to the Fourth Military Medical University, Xi'an 710038, China.
| | - Wen-Feng Xiong
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Xuan Shang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Ling-Yun Tang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Hong-Xin Zhang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Ying-Han Wan
- Shanghai Engineering and Technology Research Center for Model Animals, Shanghai Model Organisms Center, Inc., Shanghai 201318, China.
| | - You-Bing Wu
- Shanghai Engineering and Technology Research Center for Model Animals, Shanghai Model Organisms Center, Inc., Shanghai 201318, China.
| | - Jian Fei
- Shanghai Engineering and Technology Research Center for Model Animals, Shanghai Model Organisms Center, Inc., Shanghai 201318, China.
| | - Qi-Zhong Yi
- Psychological Medical Center, The First Hospital affiliated to Xin Jiang Medical University, Urumqi 830054, China; Xin Jiang Clinical Research Center for Mental Health, Urumqi 830054, China.
| | - Zhu-Gang Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200025, China; Shanghai Engineering and Technology Research Center for Model Animals, Shanghai Model Organisms Center, Inc., Shanghai 201318, China.
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Solís KH, Romero-Ávila MT, Guzmán-Silva A, García-Sáinz JA. The LPA 3 Receptor: Regulation and Activation of Signaling Pathways. Int J Mol Sci 2021; 22:ijms22136704. [PMID: 34201414 PMCID: PMC8269014 DOI: 10.3390/ijms22136704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/08/2021] [Accepted: 06/12/2021] [Indexed: 12/17/2022] Open
Abstract
The lysophosphatidic acid 3 receptor (LPA3) participates in different physiological actions and in the pathogenesis of many diseases through the activation of different signal pathways. Knowledge of the regulation of the function of the LPA3 receptor is a crucial element for defining its roles in health and disease. This review describes what is known about the signaling pathways activated in terms of its various actions. Next, we review knowledge on the structure of the LPA3 receptor, the domains found, and the roles that the latter might play in ligand recognition, signaling, and cellular localization. Currently, there is some information on the action of LPA3 in different cells and whole organisms, but very little is known about the regulation of its function. Areas in which there is a gap in our knowledge are indicated in order to further stimulate experimental work on this receptor and on other members of the LPA receptor family. We are convinced that knowledge on how this receptor is activated, the signaling pathways employed and how the receptor internalization and desensitization are controlled will help design new therapeutic interventions for treating diseases in which the LPA3 receptor is implicated.
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Mori F, Tanji K, Miki Y, Toyoshima Y, Yoshida M, Kakita A, Takahashi H, Utsumi J, Sasaki H, Wakabayashi K. G protein-coupled receptor 26 immunoreactivity in intranuclear inclusions associated with polyglutamine and intranuclear inclusion body diseases. Neuropathology 2015; 36:50-5. [DOI: 10.1111/neup.12237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/16/2015] [Accepted: 07/16/2015] [Indexed: 01/04/2023]
Affiliation(s)
- Fumiaki Mori
- Department of Neuropathology; Institute of Brain Science, Hirosaki University Graduate School of Medicine; Hirosaki
| | - Kunikazu Tanji
- Department of Neuropathology; Institute of Brain Science, Hirosaki University Graduate School of Medicine; Hirosaki
| | - Yasuo Miki
- Department of Neuropathology; Institute of Brain Science, Hirosaki University Graduate School of Medicine; Hirosaki
| | - Yasuko Toyoshima
- Department of Pathology; Brain Research Institute, University of Niigata; Niigata
| | - Mari Yoshida
- Department of Neuropathology; Aichi Medical University; Nagakute
| | - Akiyoshi Kakita
- Department of Pathological Neuroscience, Center for Bioresource-based Researches; Brain Research Institute, University of Niigata; Niigata
| | - Hitoshi Takahashi
- Department of Pathology; Brain Research Institute, University of Niigata; Niigata
| | - Jun Utsumi
- Department of Neurology; Hokkaido University Graduate School of Medicine; Sapporo Japan
| | - Hidenao Sasaki
- Department of Neurology; Hokkaido University Graduate School of Medicine; Sapporo Japan
| | - Koichi Wakabayashi
- Department of Neuropathology; Institute of Brain Science, Hirosaki University Graduate School of Medicine; Hirosaki
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Croft W, Hill C, McCann E, Bond M, Esparza-Franco M, Bennett J, Rand D, Davey J, Ladds G. A physiologically required G protein-coupled receptor (GPCR)-regulator of G protein signaling (RGS) interaction that compartmentalizes RGS activity. J Biol Chem 2013; 288:27327-27342. [PMID: 23900842 DOI: 10.1074/jbc.m113.497826] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors (GPCRs) can interact with regulator of G protein signaling (RGS) proteins. However, the effects of such interactions on signal transduction and their physiological relevance have been largely undetermined. Ligand-bound GPCRs initiate by promoting exchange of GDP for GTP on the Gα subunit of heterotrimeric G proteins. Signaling is terminated by hydrolysis of GTP to GDP through intrinsic GTPase activity of the Gα subunit, a reaction catalyzed by RGS proteins. Using yeast as a tool to study GPCR signaling in isolation, we define an interaction between the cognate GPCR (Mam2) and RGS (Rgs1), mapping the interaction domains. This reaction tethers Rgs1 at the plasma membrane and is essential for physiological signaling response. In vivo quantitative data inform the development of a kinetic model of the GTPase cycle, which extends previous attempts by including GPCR-RGS interactions. In vivo and in silico data confirm that GPCR-RGS interactions can impose an additional layer of regulation through mediating RGS subcellular localization to compartmentalize RGS activity within a cell, thus highlighting their importance as potential targets to modulate GPCR signaling pathways.
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Affiliation(s)
- Wayne Croft
- Division of Biomedical Cell Biology, Warwick Medical School
| | | | - Eilish McCann
- Division of Biomedical Cell Biology, Warwick Medical School
| | - Michael Bond
- Division of Biomedical Cell Biology, Warwick Medical School
| | | | | | - David Rand
- Systems Biology Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - John Davey
- Division of Biomedical Cell Biology, Warwick Medical School
| | - Graham Ladds
- Division of Biomedical Cell Biology, Warwick Medical School.
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5
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Design and Application of Synthetic Biology Devices for Therapy. Synth Biol (Oxf) 2013. [DOI: 10.1016/b978-0-12-394430-6.00009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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6
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Zhang LL, Wang JJ, Liu Y, Lu XB, Kuang Y, Wan YH, Chen Y, Yan HM, Fei J, Wang ZG. GPR26-deficient mice display increased anxiety- and depression-like behaviors accompanied by reduced phosphorylated cyclic AMP responsive element-binding protein level in central amygdala. Neuroscience 2011; 196:203-14. [DOI: 10.1016/j.neuroscience.2011.08.069] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 08/21/2011] [Accepted: 08/31/2011] [Indexed: 01/27/2023]
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7
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War SA, Somvanshi RK, Kumar U. Somatostatin receptor-3 mediated intracellular signaling and apoptosis is regulated by its cytoplasmic terminal. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:390-402. [PMID: 21194548 DOI: 10.1016/j.bbamcr.2010.12.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 11/25/2010] [Accepted: 12/13/2010] [Indexed: 12/25/2022]
Abstract
In the present study, we describe the role of cytoplasmic terminal (C-tail) domain in regulating coupling to adenylyl cyclase, signaling, and apoptosis in human embryonic kidney (HEK-293) cells transfected with wild type (wt)-hSSTR3 and C-tail deleted mutants. Cells transfected with wt-hSSTR3 and C-tail mutants show comparable membrane expression; however, display decreased expression in presence of agonist. wt-hSSTR3 exists as preformed homodimer at cell surface in basal conditions and decreases in response to agonist. Cells expressing C-tail mutants also show evidence of homodimerization with the same intensity as wt-hSSTR3. The agonist-dependent inhibition of cyclic adenosine monophosphate (cAMP) was lost in cells expressing C-tail mutants. Agonist treatment in cells expressing wt-hSSTR3 resulted in inhibition of cell proliferation, increased expression of PARP-1, and TUNEL positivity in proliferating cell nuclear antigen (PCNA)-positive cells. The agonist mediated increase in membrane expression of protein tyrosine phosphatase (PTP) seen with wt-hSSTR3 was diminished in C-tail mutants, which was accompanied with the loss of receptor's ability to induce apoptosis. Taken together, our data provide new insights into C-tail-dependent regulation of cell signaling and apoptosis by hSSTR3.
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Affiliation(s)
- Sajad A War
- Faculty of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, The University of British Columbia, Vancouver, BC V6T1Z3, Canada
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8
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Smith B, Hill C, Godfrey EL, Rand D, van den Berg H, Thornton S, Hodgkin M, Davey J, Ladds G. Dual positive and negative regulation of GPCR signaling by GTP hydrolysis. Cell Signal 2009; 21:1151-60. [PMID: 19285552 DOI: 10.1016/j.cellsig.2009.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 03/04/2009] [Indexed: 10/21/2022]
Abstract
G protein-coupled receptors (GPCRs) regulate a variety of intracellular pathways through their ability to promote the binding of GTP to heterotrimeric G proteins. Regulator of G protein signaling (RGS) proteins increases the intrinsic GTPase activity of Galpha-subunits and are widely regarded as negative regulators of G protein signaling. Using yeast we demonstrate that GTP hydrolysis is not only required for desensitization, but is essential for achieving a high maximal (saturated level) response. Thus RGS-mediated GTP hydrolysis acts as both a negative (low stimulation) and positive (high stimulation) regulator of signaling. To account for this we generated a new kinetic model of the G protein cycle where Galpha(GTP) enters an inactive GTP-bound state following effector activation. Furthermore, in vivo and in silico experimentation demonstrates that maximum signaling output first increases and then decreases with RGS concentration. This unimodal, non-monotone dependence on RGS concentration is novel. Analysis of the kinetic model has revealed a dynamic network motif that shows precisely how inclusion of the inactive GTP-bound state for the Galpha produces this unimodal relationship.
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Affiliation(s)
- Benjamin Smith
- Molecular Organization and Assembly of Cells Centre, University of Warwick, Coventry, UK
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9
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Poirier L, Seroude L. Genetic approaches to study aging in Drosophila melanogaster. AGE (DORDRECHT, NETHERLANDS) 2005; 27:165-82. [PMID: 23598651 PMCID: PMC3458491 DOI: 10.1007/s11357-005-2919-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 03/03/2005] [Accepted: 05/15/2005] [Indexed: 06/02/2023]
Abstract
The process of aging can be described as a progressive decline in an organism's function that invariably results in death. This decline results from the activities of intrinsic genetic factors within an organism. The relative contributions of the biological and environmental components to senescence are hard to measure, however different strategies have been devised in Drosophila melanogaster to isolate and identify genetic influences on aging. These strategies include selective breeding, quantitative trait loci (QTL) mapping and single gene mutant analysis. Selective breeding effectively demonstrated a genetic, heritable component to aging while QTL mapping located regions within the Drosophila genome carrying loci that influence the aging process. Within the past decade, single gene mutant analysis has facilitated the identification of specific genes whose activities play a determinative role in Drosophila aging. This review will focus on the application of selective breeding, QTL mapping and single gene mutant analysis used in Drosophila to study aging as well as the results obtained through these strategies to date.
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Affiliation(s)
- Luc Poirier
- Department of Biology, BioSciences Complex, Queen's University, Kingston, ON K7L 3N6 Canada
| | - Laurent Seroude
- Department of Biology, BioSciences Complex, Queen's University, Kingston, ON K7L 3N6 Canada
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10
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Schwartz NB. Perspective: reproductive endocrinology and human health in the 20th century--a personal retrospective. Endocrinology 2001; 142:2163-6. [PMID: 11356657 DOI: 10.1210/endo.142.6.8222] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- N B Schwartz
- Department of Neurobiology and Physiology Northwestern University Evanston, Illinois 60208, USA.
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11
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Coulter LJ, Wright H, Reid HW. Molecular genomic characterization of the viruses of malignant catarrhal fever. J Comp Pathol 2001; 124:2-19. [PMID: 11428184 DOI: 10.1053/jcpa.2000.0524] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- L J Coulter
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK
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12
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Rauly I, Ailhaud M, Wurch T, Pauwels PJ. alpha(2A)-adrenoceptor: G(alphai1) protein-mediated pertussis toxin-resistant attenuation of G(s) coupling to the cyclic AMP pathway. Biochem Pharmacol 2000; 59:1531-8. [PMID: 10799649 DOI: 10.1016/s0006-2952(00)00276-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Fusion proteins were constructed between a recombinant human alpha(2A)-adrenoceptor and either a rat wild-type G(alphai1) or putative pertussis toxin-resistant form of the G(alphai1) protein (G(alphai1)Cys(351)Gly). [(3)H]2-[2-(2-Methoxy-1, 4-benzodioxanyl)]imidazoline hydrochloride (RX 821002) saturation binding experiments demonstrated that both fusion proteins were expressed at a similar level as the alpha(2A)-adrenoceptor co-expressed with either a wild-type G(alphai1) or mutant G(alphai1)Cys(351)Gly protein in COS-7 cells, and displayed a ligand binding profile similar to that for the alpha(2A)-adrenoceptor protein. In alpha(2A)-adrenoceptor-transfected COS-7 cells, 5-bromo-6-(2-imidazolin-2-yl-amino) quinoxaline tartrate (brimonidine, 10 microM) induced stimulation (151 +/- 28%) of adenosine 3',5'-cyclic monophosphate (cAMP) formation which was prevented by cholera toxin treatment, demonstrating a direct coupling of the alpha(2A)-adrenoceptor to an endogenous G(alphas) protein in COS-7 cells. Expression of either the wild-type G(alphai1) or mutant G(alphai1)Cys(351)Gly protein in co-expression or fusion with the alpha(2A)-adrenoceptor in COS-7 cells suppressed the brimonidine-induced stimulation of cAMP formation, both in the presence and absence of pertussis toxin pretreatment. Hence, the G(alphai1) protein apparently blocks the G(s)-coupled alpha(2A)-adrenoceptor-mediated pathway in a pertussis toxin-non-sensitive way.
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Affiliation(s)
- I Rauly
- Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 81106, Castres, France.
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13
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Giannetti N, Enjalbert A, Krantic S. Somatostatin analog SMS 201995 inhibits proliferation in human leukemia T-cell line: relevance of the adenylyl cyclase stimulation. J Cell Biochem 2000; 78:666-73. [PMID: 10861863 DOI: 10.1002/1097-4644(20000915)78:4<666::aid-jcb15>3.0.co;2-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Octreotide SMS 201995 is a stable somatostatin (SRIF) analog with potent antiproliferative actions in numerous cell types including normal T lymphocytes. It is currently used in the clinical treatment of different malignancies. However, the possible beneficial actions of octreotide in T-cell leukemia have not been addressed before, although these cells express SRIF receptors. For instance, human leukemia Jurkat T cells have been shown to express a single SRIF receptor isotype: sst3 that can be pharmacologically targeted by octreotide. In this study, we therefore studied SMS 201995 effects on in vitro [(3)H-CH3]thymidine incorporation in Jurkat T cells. Our data show that octreotide inhibits the proliferation of Jurkat cells both in the absence and in the presence of mitogens. By contrast, SRIF28, an endogenous SRIF analog sharing with SMS 201995 an almost identical affinity for somatostatin sst3 receptors, increases [(3)H-CH3]thymidine uptake in both mitogen-activated and nonactivated cells. To assess the mechanisms of the opposite actions of these two analogs on leukemia T-cell proliferation, we next studied their effects on adenylyl cyclase activity in whole Jurkat cells. At least in the presence of mitogens, SMS 201995 significantly enhances the adenylyl cyclase activity whereas SRIF28 inhibits it. Taken together these data are in accordance with the current hypothesis according to which increase and decrease in cAMP production are required to allow the inhibition and stimulation of T-cell proliferation, respectively. They also point to a potential therapeutic benefit of SMS 201995 in the management of human T-cell leukemia.
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Affiliation(s)
- N Giannetti
- Laboratoire de Biologie Moléculaire et Cellulaire, UMR 49, Ecole Normale Supérieure, Lyon, Cédex 07, France
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14
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Bazan A, Van de Velde E, de Paepe B, Fraeyman N. Properties of the ventricular adrenergic signal transduction system during ontogeny of spontaneous hypertension in rats. J Cardiovasc Pharmacol 2000; 35:653-63. [PMID: 10774798 DOI: 10.1097/00005344-200004000-00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to characterize adrenergic receptors and associated G proteins in ventricles of spontaneously hypertensive rats (SHRs) at different stages of development. The beta- and alpha1-adrenoceptor densities and subtype distribution, and beta-adrenoceptor-G protein coupling were studied by radioligand binding, and levels of G(Salpha), G(ialpha), and G(q/11alpha) protein species were determined by Western blotting in SHRs and Wistar-Kyoto (WKY) control rats aged 3.5 weeks, 3 months, and 8 months. In 3.5-week-old SHRs, both the beta-adrenoceptor density and the percentage of agonist high-affinity binding sites were higher than in age-matched WKY rats. The beta1/beta2-subtype distribution, the alpha1-adrenoceptor density, and the alpha1B/alpha1A-subtype distribution were similar in rats of both strains at all ages. Although essentially no differences in G(salpha) levels between SHRs and WKY rats were detected, higher G(ialpha) and lower Gq/1alpha concentrations were found in 3.5-week-old SHRs. In 3-month-old SHRs, increased levels of Gq/11alpha proteins were observed. In 8-month-old SHRs, none of the parameters was different from those of controls. We conclude that the differences in properties of the adrenergic signal transduction system between SHRs and WKY rats are exclusively observable before and at the onset of the overt hypertension. Moreover, the hypertensive genotype apparently affects G proteins more readily than adrenoceptors.
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Affiliation(s)
- A Bazan
- Ghent University, Medical School, Heymans Institute of Pharmacology, Belgium
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15
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O'Dowd BF, Lee DK, Huang W, Nguyen T, Cheng R, Liu Y, Wang B, Gershengorn MC, George SR. TRH-R2 exhibits similar binding and acute signaling but distinct regulation and anatomic distribution compared with TRH-R1. Mol Endocrinol 2000; 14:183-93. [PMID: 10628757 DOI: 10.1210/mend.14.1.0407] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
TRH (thyroliberin) is a tripeptide (pGlu-His-ProNH2) that signals via G protein-coupled receptors. Until recently, only a single receptor for TRH was known (TRH-R1), but two groups identified a second receptor, TRH-R2. We independently discovered TRH-R2. Using an extensive set of TRH analogs, we found no differences in TRH-R1 and TRH-R2 binding or in acute stimulation of signaling. TRH-R2 was more rapidly internalized upon binding TRH and exhibited a greater level of TRH-induced down-regulation than TRH-R1. During prolonged exposure to TRH, cells expressing TRH-R2 exhibited a lower level of gene induction than cells expressing TRH-R1. TRH-R2 receptor mRNA was present in very discrete nuclei and regions of rat brain. A major mRNA transcript for TRH-R2 was seen in the cerebral cortex, pons, thalamus, hypothalamus, and midbrain with faint bands found in the striatum and pituitary. The extensive distribution of TRH-R2 in the brain suggests that it mediates many of the known functions of TRH that are not transduced by TRH-R1. The variations in agonist-induced internalization and down-regulation/desensitization, and anatomic distribution of TRH-R2 compared with TRH-R1, suggest important functional differences between the two receptors.
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Affiliation(s)
- B F O'Dowd
- Department of Pharmacology, University of Toronto, Ontario, Canada
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16
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Loisel TP, Ansanay H, Adam L, Marullo S, Seifert R, Lagacé M, Bouvier M. Activation of the beta(2)-adrenergic receptor-Galpha(s) complex leads to rapid depalmitoylation and inhibition of repalmitoylation of both the receptor and Galpha(s). J Biol Chem 1999; 274:31014-9. [PMID: 10521499 DOI: 10.1074/jbc.274.43.31014] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Palmitoylation is unique among lipid modifications in that it is reversible. In recent years, dynamic palmitoylation of G protein alpha subunits and of their cognate receptors has attracted considerable attention. However, very little is known concerning the acylation/deacylation cycle of the proteins in relation to their activity status. In particular, the relative contribution of the activation and desensitization of the signaling unit to the regulation of the receptors and G proteins palmitoylation state is unknown. To address this issue, we took advantage of the fact that a fusion protein composed of the stimulatory alpha subunit of trimeric G protein (Galpha(s)) covalently attached to the beta(2)-adrenergic receptor (beta(2)AR) as a carboxyl-terminal extension (beta(2)AR-Galpha(s)) can be stimulated by agonists but does not undergo rapid inactivation, desensitization, or internalization. When expressed in Sf9 cells, both the receptor and the Galpha(s) moieties of the fusion protein were found to be palmitoylated via thioester linkage. Stimulation with the beta-adrenergic agonist isoproterenol led to a rapid depalmitoylation of both the beta(2)AR and Galpha(s) and inhibited repalmitoylation. The extent of depalmitoylation induced by a series of agonists was correlated (0.99) with their intrinsic efficacy to stimulate the adenylyl cyclase activity. However, forskolin-stimulated cAMP production did not affect the palmitoylation state of beta(2)AR-Galpha(s), indicating that the agonist-promoted depalmitoylation is linked to conformational changes and not to second messenger generation. Given that, upon activation, the fusion protein mimics the activated receptor-G protein complex but cannot undergo desensitization, the data demonstrate that early steps in the activation process lead to the depalmitoylation of both receptor and G protein and that repalmitoylation requires later events that cannot be accommodated by the activated fusion protein.
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MESH Headings
- Animals
- Cell Line
- Cloning, Molecular
- Cyanogen Bromide
- GTP-Binding Protein alpha Subunits, Gs/chemistry
- GTP-Binding Protein alpha Subunits, Gs/isolation & purification
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Humans
- Hydroxylamine/pharmacology
- Isoproterenol/pharmacology
- Kinetics
- Macromolecular Substances
- Palmitic Acid/metabolism
- Peptide Fragments/chemistry
- Peptide Fragments/isolation & purification
- Protein Processing, Post-Translational
- Receptors, Adrenergic, beta-2/chemistry
- Receptors, Adrenergic, beta-2/isolation & purification
- Receptors, Adrenergic, beta-2/metabolism
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Fusion Proteins/metabolism
- Spodoptera
- Transfection
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Affiliation(s)
- T P Loisel
- Département de Biochimie and Groupe de Recherche sur le Système Nerveux Autonome, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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17
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Milligan G. Exploring the dynamics of regulation of G protein-coupled receptors using green fluorescent protein. Br J Pharmacol 1999; 128:501-10. [PMID: 10516625 PMCID: PMC1571667 DOI: 10.1038/sj.bjp.0702824] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/1999] [Accepted: 07/02/1999] [Indexed: 11/09/2022] Open
Affiliation(s)
- G Milligan
- Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow.
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18
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Groarke DA, Wilson S, Krasel C, Milligan G. Visualization of agonist-induced association and trafficking of green fluorescent protein-tagged forms of both beta-arrestin-1 and the thyrotropin-releasing hormone receptor-1. J Biol Chem 1999; 274:23263-9. [PMID: 10438501 DOI: 10.1074/jbc.274.33.23263] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A fusion protein (beta-arrestin-1-green fluorescent protein (GFP)) was constructed between beta-arrestin-1 and a modified form of the green fluorescent protein from Aequorea victoria. Expression in HEK293 cells allowed immunological detection of an 82-kDa cytosolic polypeptide with antisera to both beta-arrestin-1 and GFP. Transient expression of this construct in HEK293 cells stably transfected to express the rat thyrotropin-releasing hormone receptor-1 (TRHR-1) followed by confocal microscopy allowed its visualization evenly distributed throughout the cytoplasm. Addition of thyrotropin-releasing hormone (TRH) caused a profound and rapid redistribution of beta-arrestin-1-GFP to the plasma membrane followed by internalization of beta-arrestin-1-GFP into distinct, punctate, intracellular vesicles. TRH did not alter the cellular distribution of GFP transiently transfected into these cells nor the distribution of beta-arrestin-1-GFP following expression in HEK293 cells lacking the receptor. To detect potential co-localization of the receptor and beta-arrestin-1 in response to agonist treatment, beta-arrestin-1-GFP was expressed stably in HEK293 cells. A vesicular stomatitis virus (VSV)-tagged TRHR-1 was then introduced transiently. Initially, the two proteins were fully resolved. Short term exposure to TRH resulted in their plasma membrane co-localization, and sustained exposure to TRH resulted in their co-localization in punctate, intracellular vesicles. In contrast, beta-arrestin-1-GFP did not relocate or adopt a punctate appearance in cells that did not express VSV-TRHR-1. Reciprocal experiments were performed, with equivalent results, following transient expression of beta-arrestin-1 into cells stably expressing VSVTRHR-1-GFP. These results demonstrate the capacity of beta-arrestin-1-GFP to interact with the rat TRHR-1 and directly visualizes their recruitment from cytoplasm and plasma membrane respectively into overlapping, intracellular vesicles in an agonist-dependent manner.
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Affiliation(s)
- D A Groarke
- Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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19
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Dupuis DS, Tardif S, Wurch T, Colpaert FC, Pauwels PJ. Modulation of 5-HT1A receptor signalling by point-mutation of cysteine351 in the rat Galpha(o) protein. Neuropharmacology 1999; 38:1035-41. [PMID: 10428422 DOI: 10.1016/s0028-3908(99)00033-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The activity state of G proteins is involved in the ligands' maximal responses that can be produced by activating the 5-HT1A receptor (Pauwels et al., 1997). The present study investigated the ligand responses at the recombinant h 5-HT1A receptor (RC: 2.1.5HT.01A) as mediated by the Galpha(o) protein. Therefore, a fusion protein was constructed between the 5-HT1A receptor and a pertussis toxin resistant rat Galpha(o)Cys351Gly mutant protein to define its pharmacological properties at a receptor: Galpha(o) protein density ratio of 1. Pertussis toxin treatment (100 ng/ml) affected neither the expression of the 5-HT1A receptor fusion protein as measured by [3H] MPPF (3.0+/-0.7 pmol/mg protein) nor the 5-HT-mediated [35S]GTPgammaS binding response (146+/-34 fmol/mg protein) in Cos-7 cells. 8-OH-DPAT (Emax: 55+/-7%) and buspirone (Emax: 22+/-4%) yielded partial agonist activity as compared to 5-HT, whereas WAY 100635 acted as a competitive antagonist (pK(B): 9.75+/-0.17). The magnitude of the 8-OH-DPAT response (Emax, %) was highly dependent on the nature of the amino acid 351 in the C-terminus of the Galpha(o) protein: Ile351 (93+/-4) > Cys351 (79+/-3) > Gly351 (55+/-7). The Emax values (%) of buspirone displayed the following gradient: 69+/-5 approximately/= 62+/-8 > 22+/-4. For comparison, maximal responses of 8-OH-DPAT and buspirone were enhanced versus 5-HT upon co-expression of the 5-HT1A receptor with the respective Galpha(o) proteins, probably due to an altered receptor: Galpha(o) protein density ratio. In conclusion, residue 351 of the rat Galpha(o) protein is involved in determining the magnitude of 5-HT1A receptor activation that ligands can produce at these receptors. Moreover, the fusion protein approach allows quantitative comparisons of the intrinsic activities of ligands between one single receptor subtype with different Galpha protein subtypes.
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Affiliation(s)
- D S Dupuis
- Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, CASTRES, France
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20
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Drmota T, Gould GW, Milligan G. Real time visualization of agonist-mediated redistribution and internalization of a green fluorescent protein-tagged form of the thyrotropin-releasing hormone receptor. J Biol Chem 1998; 273:24000-8. [PMID: 9727016 DOI: 10.1074/jbc.273.37.24000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The long isoform of the rat thyrotropin-releasing hormone receptor (TRHR) was modified by the addition of a vesicular stomatitis virus (VSV) epitope tag and green fluorescent protein (GFP). VSV-TRHR-GFP bound TRH with affinity similar to that of the unmodified receptor and stimulated [3H]inositol phosphate production. A clone stably expressing VSV-TRHR-GFP at some 120,000 copies/cell was selected to visualize this receptor during cellular exposure to TRH. Internalization was detected within 3-5 min after treatment with 1 x 10(-7) M TRH, with dramatic reductions in plasma membrane localization achieved within 10-15 min. The TRHR antagonist/inverse agonist chlordiazepoxide competitively inhibited internalization. Hyperosmotic sucrose inhibited internalization of VSV-TRHR-GFP, measured both by intact cell [3H]TRH binding studies and by confocal microscopy. Now TRH caused a redistribution of VSV-TRHR-GFP to highly punctate but plasma membrane-delineated foci. Pretreatment with the microtubule-disrupting agent nocodazole allowed internalization of the VSV-TRHR-GFP construct but only into vesicles that remained in close apposition to the plasma membrane. Covisualization of VSV-TRHR-GFP and Texas Red transferrin initially indicated entirely separate localizations. After exposure to TRH substantial amounts of VSV-TRHR-GFP were present in vesicles overlapping those containing Texas Red transferrin. Such results demonstrate the G protein-coupling capacity and provide real time visualization of the processes of internalization of a TRH-receptor-GFP construct in response to agonist.
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Affiliation(s)
- T Drmota
- Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ Scotland, United Kingdom
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