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Lamri A, De Paoli M, De Souza R, Werstuck G, Anand S, Pigeyre M. Insight into genetic, biological, and environmental determinants of sexual-dimorphism in type 2 diabetes and glucose-related traits. Front Cardiovasc Med 2022; 9:964743. [PMID: 36505380 PMCID: PMC9729955 DOI: 10.3389/fcvm.2022.964743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/21/2022] [Indexed: 11/25/2022] Open
Abstract
There is growing evidence that sex and gender differences play an important role in risk and pathophysiology of type 2 diabetes (T2D). Men develop T2D earlier than women, even though there is more obesity in young women than men. This difference in T2D prevalence is attenuated after the menopause. However, not all women are equally protected against T2D before the menopause, and gestational diabetes represents an important risk factor for future T2D. Biological mechanisms underlying sex and gender differences on T2D physiopathology are not yet fully understood. Sex hormones affect behavior and biological changes, and can have implications on lifestyle; thus, both sex-specific environmental and biological risk factors interact within a complex network to explain the differences in T2D risk and physiopathology in men and women. In addition, lifetime hormone fluctuations and body changes due to reproductive factors are generally more dramatic in women than men (ovarian cycle, pregnancy, and menopause). Progress in genetic studies and rodent models have significantly advanced our understanding of the biological pathways involved in the physiopathology of T2D. However, evidence of the sex-specific effects on genetic factors involved in T2D is still limited, and this gap of knowledge is even more important when investigating sex-specific differences during the life course. In this narrative review, we will focus on the current state of knowledge on the sex-specific effects of genetic factors associated with T2D over a lifetime, as well as the biological effects of these different hormonal stages on T2D risk. We will also discuss how biological insights from rodent models complement the genetic insights into the sex-dimorphism effects on T2D. Finally, we will suggest future directions to cover the knowledge gaps.
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Affiliation(s)
- Amel Lamri
- Department of Medicine, McMaster University, Hamilton, ON, Canada,Population Health Research Institute (PHRI), Hamilton, ON, Canada
| | - Monica De Paoli
- Department of Medicine, McMaster University, Hamilton, ON, Canada,Thrombosis and Atherosclerosis Research Institute (TaARI), Hamilton, ON, Canada
| | - Russell De Souza
- Population Health Research Institute (PHRI), Hamilton, ON, Canada,Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - Geoff Werstuck
- Department of Medicine, McMaster University, Hamilton, ON, Canada,Thrombosis and Atherosclerosis Research Institute (TaARI), Hamilton, ON, Canada
| | - Sonia Anand
- Department of Medicine, McMaster University, Hamilton, ON, Canada,Population Health Research Institute (PHRI), Hamilton, ON, Canada,Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - Marie Pigeyre
- Department of Medicine, McMaster University, Hamilton, ON, Canada,Population Health Research Institute (PHRI), Hamilton, ON, Canada,*Correspondence: Marie Pigeyre
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2
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Wang S, Zhang C, Chen R. Circ_0006220 promotes non-small cell lung cancer progression via sponging miR-203-3p and regulating RGS17 expression. Hum Exp Toxicol 2022; 41:9603271211062854. [PMID: 35041543 DOI: 10.1177/09603271211062854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Lung cancer is the most common malignancy, and its mortality ranks first among malignancies. Non-small cell lung carcinoma (NSCLC) is the most common pathological subtype of lung cancer. It is reported that circular RNAs (circRNAs) feature prominently in the occurrence and metastasis of NSCLC. PURPOSE This study aims to decipher the biological functions of circ_0006220 in NSCLC and the underlying mechanism. METHODS The microarray data (GSE101586) were downloaded from the Gene Expression Omnibus database, and differentially expressed circRNAs in NSCLC tissues were screened using the GEO2R tool. Quantitative real-time polymerase chain reaction was used for detecting the expression of circ_0006220, miR-203-3p, and regulator of G-protein signaling 17 (RGS17) mRNA in NSCLC tissues and cells. The connection between circ_0006220 expression and clinicopathological indicators was analyzed through the chi-square test. EdU and cell counting kit-8 assays were carried out to detect cell growth. Cell migration and invasion were detected by transwell assays. Bioinformatics was used to predict, and RNA immunoprecipitation assay and dual-luciferase reporter gene assay were conducted for verifying, the targeted relationship among circ_0006220, miR-203-3p, and RGS17. RESULTS The expression of circ_0006220 was elevated in NSCLC cells and tissues, and high circ_0006220 expression was significantly associated with unfavorable clinicopathological indicators. In addition, it was revealed that circ_0006220 overexpression facilitated NSCLC cell growth, migration, and invasion, whereas knocking down circ_0006220 had contrary effects. Furthermore, miR-203-3p was identified as a downstream target of circ_0006220, and circ_0006220 could sponge miR-203-3p; RGS17 was identified as a downstream target of miR-203-3p and was positively modulated by circ_0006220. CONCLUSIONS Circ_0006220 up-regulates RGS17 expression by adsorbing miR-203-3p to promote NSCLC development.
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Affiliation(s)
- Shaochun Wang
- Department of Respiratory and Critical Care Medicine, 159431Shaanxi Provincial People's Hospital, Xi'an, China
| | - Chengcheng Zhang
- Department of Respiratory and Critical Care Medicine, 159431Shaanxi Provincial People's Hospital, Xi'an, China
| | - Ruilin Chen
- Department of Respiratory and Critical Care Medicine, 159431Shaanxi Provincial People's Hospital, Xi'an, China
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3
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Dhukhwa A, Al Aameri RFH, Sheth S, Mukherjea D, Rybak L, Ramkumar V. Regulator of G protein signaling 17 represents a novel target for treating cisplatin induced hearing loss. Sci Rep 2021; 11:8116. [PMID: 33854102 PMCID: PMC8046767 DOI: 10.1038/s41598-021-87387-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/26/2021] [Indexed: 12/28/2022] Open
Abstract
Regulators of G protein signaling (RGS) accelerate the GTPase activity of G proteins to enable rapid termination of the signals triggered by G protein-coupled receptors (GPCRs). Activation of several GPCRs, including cannabinoid receptor 2 (CB2R) and adenosine A1 receptor (A1AR), protects against noise and drug-induced ototoxicity. One such drug, cisplatin, an anticancer agent used to treat various solid tumors, produces permanent hearing loss in experimental animals and in a high percentage of cancer patients who undergo treatments. In this study we show that cisplatin induces the expression of the RGS17 gene and increases the levels of RGS17 protein which contributes to a significant proportion of the hearing loss. Knockdown of RGS17 suppressed cisplatin-induced hearing loss in male Wistar rats, while overexpression of RGS17 alone produced hearing loss in vivo. Furthermore, RGS17 and CB2R negatively regulate the expression of each other. These data suggest that RGS17 mediates cisplatin ototoxicity by uncoupling cytoprotective GPCRs from their normal G protein interactions, thereby mitigating the otoprotective contributions of endogenous ligands of these receptors. Thus, RGS17 represents a novel mediator of cisplatin ototoxicity and a potential therapeutic target for treating hearing loss.
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Affiliation(s)
- Asmita Dhukhwa
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, 62702, USA
| | - Raheem F H Al Aameri
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, 62702, USA
| | - Sandeep Sheth
- Department of Pharmaceutical Sciences, Larkin University College of Pharmacy, Miami, FL, 33169, USA
| | - Debashree Mukherjea
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, 62702, USA
| | - Leonard Rybak
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, 62702, USA
| | - Vickram Ramkumar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, 62702, USA.
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4
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Ma J, Wei H, Li X, Qu X. Hsa-miR-149-5p Suppresses Prostate Carcinoma Malignancy by Suppressing RGS17. Cancer Manag Res 2021; 13:2773-2783. [PMID: 33790651 PMCID: PMC8007479 DOI: 10.2147/cmar.s281968] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/19/2021] [Indexed: 12/16/2022] Open
Abstract
Background MicroRNAs (miRNAs) are key players in the progression of human cancers. While several miRNAs have been reported to regulate the development of tumors, the molecular mechanisms and roles of miR-149-5p in prostate carcinoma (PCa) remain unclear. Our aim was to investigate the interaction and functions of miR-149-5p and RGS17 in PCa. Methods Microarray analysis was performed to identify the key miRNA and gene involved in PCa progression. The expression levels of miRNA and mRNA in PCa tissues and cells were verified by qRT-PCR. MTT assay, BrdU proliferation assay and wound-healing assay were applied to assess the effect of miR-149-5p and RGS17 on PCa cells’ viability, proliferation, and migration ability. The association between RGS17 and miR-149-5p was identify using dual-luciferase reporter assay and Western blot assay. Results Data analysis indicated the reduction of miR-149-5p expression in PCa tissues and cells. Experimental investigations also showed that this miRNA suppressed the viability, proliferation and migration ability of PCa cells. RGS17 was found to be the target of miR-149-5p, and the low expression of miR-149-5p upregulated RGS17 in PCa tissues and cells. The results of the cell-function assays showed that RGS17 acted as an oncogene in PCa even though its promotive effect could be reversed by miR-149-5p. Conclusion This research confirmed that by targeting and inhibiting RGS17, miR-149-5p could suppress PCa development.
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Affiliation(s)
- Jinhua Ma
- Department of Urinary Surgery, The Third People's Hospital of Hubei Province, Wuhan, Hubei, 430030, People's Republic of China
| | - Hongbing Wei
- Department of Urinary Surgery, The Third People's Hospital of Hubei Province, Wuhan, Hubei, 430030, People's Republic of China
| | - Xianlin Li
- Department of Urinary Surgery, The Third People's Hospital of Hubei Province, Wuhan, Hubei, 430030, People's Republic of China
| | - Xi Qu
- Department of Urinary Surgery, The Third People's Hospital of Hubei Province, Wuhan, Hubei, 430030, People's Republic of China
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Berg DJ, Kartheiser K, Leyrer M, Saali A, Berson DM. Transcriptomic Signatures of Postnatal and Adult Intrinsically Photosensitive Ganglion Cells. eNeuro 2019; 6:ENEURO.0022-19.2019. [PMID: 31387875 PMCID: PMC6712207 DOI: 10.1523/eneuro.0022-19.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 11/21/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are rare mammalian photoreceptors essential for non-image-forming vision functions, such as circadian photoentrainment and the pupillary light reflex. They comprise multiple subtypes distinguishable by morphology, physiology, projections, and levels of expression of melanopsin (Opn4), their photopigment. The molecular programs that distinguish ipRGCs from other ganglion cells and ipRGC subtypes from one another remain elusive. Here, we present comprehensive gene expression profiles of early postnatal and adult mouse ipRGCs purified from two lines of reporter mice that mark different sets of ipRGC subtypes. We find dozens of novel genes highly enriched in ipRGCs. We reveal that Rasgrp1 and Tbx20 are selectively expressed in subsets of ipRGCs, though these molecularly defined groups imperfectly match established ipRGC subtypes. We demonstrate that the ipRGCs regulating circadian photoentrainment are diverse at the molecular level. Our findings reveal unexpected complexity in gene expression patterns across mammalian ipRGC subtypes.
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Affiliation(s)
- Daniel J Berg
- Molecular Biology, Cellular Biology, and Biochemistry Program, Brown University, Providence, Rhode Island 02912
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
| | | | - Megan Leyrer
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
| | - Alexandra Saali
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
| | - David M Berson
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
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6
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Sieng M, Hayes MP, O'Brien JB, Andrew Fowler C, Houtman JC, Roman DL, Lyon AM. High-resolution structure of RGS17 suggests a role for Ca 2+ in promoting the GTPase-activating protein activity by RZ subfamily members. J Biol Chem 2019; 294:8148-8160. [PMID: 30940727 DOI: 10.1074/jbc.ra118.006059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/27/2019] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling (RGS) proteins are negative regulators of G protein-coupled receptor (GPCR) signaling through their ability to act as GTPase-activating proteins (GAPs) for activated Gα subunits. Members of the RZ subfamily of RGS proteins bind to activated Gαo, Gαz, and Gαi1-3 proteins in the nervous system and thereby inhibit downstream pathways, including those involved in Ca2+-dependent signaling. In contrast to other RGS proteins, little is known about RZ subfamily structure and regulation. Herein, we present the 1.5-Å crystal structure of RGS17, the most complete and highest-resolution structure of an RZ subfamily member to date. RGS17 cocrystallized with Ca2+ bound to conserved positions on the predicted Gα-binding surface of the protein. Using NMR chemical shift perturbations, we confirmed that Ca2+ binds in solution to the same site. Furthermore, RGS17 had greater than 55-fold higher affinity for Ca2+ than for Mg2+ Finally, we found that Ca2+ promotes interactions between RGS17 and activated Gα and decreases the Km for GTP hydrolysis, potentially by altering the binding mechanism between these proteins. Taken together, these findings suggest that Ca2+ positively regulates RGS17, which may represent a general mechanism by which increased Ca2+ concentration promotes the GAP activity of the RZ subfamily, leading to RZ-mediated inhibition of Ca2+ signaling.
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Affiliation(s)
- Monita Sieng
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Michael P Hayes
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242
| | - Joseph B O'Brien
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242
| | - C Andrew Fowler
- NMR Facility, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jon C Houtman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa 52242
| | - David L Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242
| | - Angeline M Lyon
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907; Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
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7
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Squires KE, Montañez-Miranda C, Pandya RR, Torres MP, Hepler JR. Genetic Analysis of Rare Human Variants of Regulators of G Protein Signaling Proteins and Their Role in Human Physiology and Disease. Pharmacol Rev 2018; 70:446-474. [PMID: 29871944 DOI: 10.1124/pr.117.015354] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate the physiologic actions of many neurotransmitters, hormones, and other signaling molecules. Human RGS proteins comprise a family of 20 canonical proteins that bind directly to G protein-coupled receptors/G protein complexes to limit the lifetime of their signaling events, which regulate all aspects of cell and organ physiology. Genetic variations account for diverse human traits and individual predispositions to disease. RGS proteins contribute to many complex polygenic human traits and pathologies such as hypertension, atherosclerosis, schizophrenia, depression, addiction, cancers, and many others. Recent analysis indicates that most human diseases are due to extremely rare genetic variants. In this study, we summarize physiologic roles for RGS proteins and links to human diseases/traits and report rare variants found within each human RGS protein exome sequence derived from global population studies. Each RGS sequence is analyzed using recently described bioinformatics and proteomic tools for measures of missense tolerance ratio paired with combined annotation-dependent depletion scores, and protein post-translational modification (PTM) alignment cluster analysis. We highlight selected variants within the well-studied RGS domain that likely disrupt RGS protein functions and provide comprehensive variant and PTM data for each RGS protein for future study. We propose that rare variants in functionally sensitive regions of RGS proteins confer profound change-of-function phenotypes that may contribute, in newly appreciated ways, to complex human diseases and/or traits. This information provides investigators with a valuable database to explore variation in RGS protein function, and for targeting RGS proteins as future therapeutic targets.
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Affiliation(s)
- Katherine E Squires
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Carolina Montañez-Miranda
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Rushika R Pandya
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Matthew P Torres
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
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8
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Yu Q, Zhang N, Jiang Y, Huang Y, Lian YY, Liu T, Li N, Guan G. RGS17 inhibits tumorigenesis and improves 5-fluorouracil sensitivity in nasopharyngeal carcinoma. Onco Targets Ther 2018; 11:7591-7600. [PMID: 30464507 PMCID: PMC6223391 DOI: 10.2147/ott.s176002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background Nasopharyngeal carcinoma (NPC) is a poorly differentiated malignant tumor, and 5-fluorouracil (5-FU) is one of the most effective chemotherapeutic drugs used for the treatment of NPC. Abnormal expression of RGS17 had been shown to improve the sensitivity of many cancers to chemotherapy; however, the effects of RGS17 on NPC remain unclear. Methods We cultured NPC cell lines and altered the RGS17 expression with vector. Subsequently colony formation assays and CCK8 cell viability assay was used to test the proliferation of NPC cells, flow cytometry was used to determine the percentage of apoptotic cells, MMP kit and flow cytometry was used to measure the mitochondrial membrane potential, and a xenograft tumour model was attached to investigate the effects of RGS17 on the growth of NPC cells in vivo. Additionally, RT-PCR and western blot was induced to examine the expression of RGS17 and the mechanism. Results Here, we report for the first time that RGS17 is downregulated in NPC cell lines and that RGS17 overexpression significantly reduces cell proliferation, decreases the mitochondrial membrane potential, and induces cell apoptosis in NPC cells. In vivo, RGS17 also inhibits the tumorigenicity of NPC. In addition, RGS17 could significantly improve the sensitivity of NPC cells to 5-FU. Furthermore, investigation into the underlying mechanisms showed that RGS17 upregulated the levels of IRE1α, p53, and active caspase-3 and cleaved PARP. Conclusion These results indicate that RGS17 could play important roles in the proliferation, apoptosis, and chemotherapeutic sensitivity of NPC cells.
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Affiliation(s)
- Qianqian Yu
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Niankai Zhang
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Yan Jiang
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Yichuan Huang
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Yuan-Yuan Lian
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Tingting Liu
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Na Li
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, Qingdao, China,
| | - Ge Guan
- Department of Organ Transplantation, Affiliated Hospital of Qingdao University, Qingdao, China,
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Structural motifs in the RGS RZ subfamily combine to attenuate interactions with Gα subunits. Biochem Biophys Res Commun 2018; 503:2736-2741. [DOI: 10.1016/j.bbrc.2018.08.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/03/2018] [Indexed: 11/20/2022]
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10
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Hayes MP, Bodle CR, Roman DL. Evaluation of the Selectivity and Cysteine Dependence of Inhibitors across the Regulator of G Protein-Signaling Family. Mol Pharmacol 2018; 93:25-35. [PMID: 29051318 PMCID: PMC5708088 DOI: 10.1124/mol.117.109843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/16/2017] [Indexed: 01/03/2023] Open
Abstract
Since their discovery more than 20 years ago, regulators of G protein-signaling (RGS) proteins have received considerable attention as potential drug targets because of their ability to modulate Gα activity. Efforts to identify small molecules capable of inhibiting the protein-protein interactions between activated Gα subunits and RGS proteins have yielded a substantial number of inhibitors, especially toward the well studied RGS4. These efforts also determined that many of these small molecules inhibit the protein-protein interactions through covalent modification of cysteine residues within the RGS domain that are located distal to the Gα-binding interface. As some of these cysteine residues are highly conserved within the RGS family, many of these inhibitors display activity toward multiple RGS family members. In this work, we sought to determine the selectivity of these small-molecule inhibitors against 12 RGS proteins, as well as against the cysteine-null mutants for 10 of these proteins. Using both biochemical and cell-based methods to assess Gα-RGS complex formation and Gα enzymatic activity, we found that several previously identified RGS4 inhibitors were active against other RGS members, such as RGS14, with comparable or greater potency. Additionally, for every compound tested, activity was dependent on the presence of cysteine residues. This work defines the selectivity of commercially available RGS inhibitors and provides insight into the RGS family members for which drug discovery efforts may be most likely to succeed.
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Affiliation(s)
- Michael P Hayes
- Department of Pharmaceutical Sciences and Experimental Therapeutics University of Iowa (M.P.H., C.R.B., D.L.R.) and Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics (D.L.R.), Iowa City, Iowa
| | - Christopher R Bodle
- Department of Pharmaceutical Sciences and Experimental Therapeutics University of Iowa (M.P.H., C.R.B., D.L.R.) and Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics (D.L.R.), Iowa City, Iowa
| | - David L Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics University of Iowa (M.P.H., C.R.B., D.L.R.) and Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics (D.L.R.), Iowa City, Iowa
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11
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Chi Y, Jin Q, Liu X, Xu L, He X, Shen Y, Zhou Q, Zhang J, Jin M. miR-203 inhibits cell proliferation, invasion, and migration of non-small-cell lung cancer by downregulating RGS17. Cancer Sci 2017; 108:2366-2372. [PMID: 28921827 PMCID: PMC5715240 DOI: 10.1111/cas.13401] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 12/24/2022] Open
Abstract
Involvement of the RGS17 oncogene in the promotion of non‐small‐cell lung cancer (NSCLC) has been reported, but the regulation mechanism in NSCLC remains unclear. MicroRNAs (miRNAs) negatively regulate gene expression, and their dysregulation has been implicated in tumorigenesis. To understand the role of miRNAs in Regulator of G Protein Signaling 17 (RGS17)‐induced NSCLC, we showed that miR‐203 was downregulated during tumorigenesis, and inhibited the proliferation and invasion of lung cancer cells. We then determined whether miR‐203 regulated NSCLC by targeting RGS17. To characterize the regulatory effect of miR‐203 on RGS17, we used lung cancer cell lines, A549 and Calu‐1, and the constructed miR‐203 and RGS17 overexpression vectors. The CCK8 kit was used to determine cell proliferation, and the Transwell® assay was used to measure cell invasion and migration. RT‐PCR, western blots, and immunofluorescence were used to analyze expression of miR‐203 and RGS17, and the luciferase reporter assay was used to examine the interaction between miR‐203 and RGS17. Nude mice were used to characterize in vivo tumor growth regulation. Expression of miR‐203 inhibited proliferation, invasion, and migration of lung cancer cell lines A549 and Calu‐1 by targeting RGS17. The regulatory effect of miR‐203 was inhibited after overexpression of RGS17. The luciferase reporter assay showed that miR‐203 downregulated RGS17 by direct integration into the 3′‐UTR of RGS17 mRNA. In vivo studies showed that expression of miR‐203 significantly inhibited growth of tumors. Taken together, the results suggested that expression of miR‐203 inhibited tumor growth and metastasis by targeting RGS17.
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Affiliation(s)
- Yongbin Chi
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Qinqin Jin
- Department of Emergency Medicine, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Xinghui Liu
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Limin Xu
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Xiaoxue He
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Yan Shen
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Qiang Zhou
- Medical Laboratory, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
| | - Jue Zhang
- Clinical Laboratory, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Mingming Jin
- Department of Emergency Medicine, Shanghai Pudong New Area Gongli Hospital, The Second Military Medical University, Shanghai, China
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12
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Bodle CR, Mackie DI, Hayes MP, Schamp JH, Miller MR, Henry MD, Doorn JA, Houtman JCD, James MA, Roman DL. Natural Products Discovered in a High-Throughput Screen Identified as Inhibitors of RGS17 and as Cytostatic and Cytotoxic Agents for Lung and Prostate Cancer Cell Lines. JOURNAL OF NATURAL PRODUCTS 2017. [PMID: 28621943 PMCID: PMC5567870 DOI: 10.1021/acs.jnatprod.7b00112] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Regulator of G Protein Signaling (RGS) 17 is an overexpressed promoter of cancer survival in lung and prostate tumors, the knockdown of which results in decreased tumor cell proliferation in vitro. Identification of drug-like molecules inhibiting this protein could ameliorate the RGS17's pro-tumorigenic effect. Using high-throughput screening, a chemical library containing natural products was interrogated for inhibition of the RGS17-Gαo interaction. Initial hits were verified in control and counter screens. Leads were characterized via biochemical, mass spectrometric, Western blot, microscopic, and cytotoxicity measures. Four known compounds (1-4) were identified with IC50 values ranging from high nanomolar to low micromolar. Three compounds were extensively characterized biologically, demonstrating cellular activity determined by confocal microscopy, and two compounds were assessed via ITC exhibiting high nanomolar to low micromolar dissociation constants. The compounds were found to have a cysteine-dependent mechanism of binding, verified through site-directed mutagenesis and cysteine reactivity assessment. Two compounds, sanguinarine (1) and celastrol (2), were found to be cytostatic against lung and prostate cancer cell lines and cytotoxic against prostate cancer cell lines in vitro, although the dependence of RGS17 on these phenomena remains elusive, a result that is perhaps not surprising given the multimodal cytostatic and cytotoxic activities of many natural products.
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Affiliation(s)
- Christopher R. Bodle
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Duncan I. Mackie
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
- Holden Comprehensive Cancer Center, UIHC, University of Iowa, Iowa City, Iowa 52242, United States
| | - Michael P. Hayes
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Josephine H Schamp
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Michael R. Miller
- Holden Comprehensive Cancer Center, UIHC, University of Iowa, Iowa City, Iowa 52242, United States
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Michael D. Henry
- Department of Molecular Physiology, Biophysics, and Pathology, Holden Comprehensive Cancer Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Jonathan A. Doorn
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Jon C. D. Houtman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary Graduate Program in Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Michael A. James
- Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
- Pancreatic Cancer Program at the Medical College of Wisconsin, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - David L. Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242, United States
- Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, UIHC, University of Iowa, Iowa City, Iowa 52242, United States
- Corresponding Author. Tel: 319-335-6920. Fax: 319-335-8766.
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13
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Gendron L, Cahill CM, von Zastrow M, Schiller PW, Pineyro G. Molecular Pharmacology of δ-Opioid Receptors. Pharmacol Rev 2017; 68:631-700. [PMID: 27343248 DOI: 10.1124/pr.114.008979] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Opioids are among the most effective analgesics available and are the first choice in the treatment of acute severe pain. However, partial efficacy, a tendency to produce tolerance, and a host of ill-tolerated side effects make clinically available opioids less effective in the management of chronic pain syndromes. Given that most therapeutic opioids produce their actions via µ-opioid receptors (MOPrs), other targets are constantly being explored, among which δ-opioid receptors (DOPrs) are being increasingly considered as promising alternatives. This review addresses DOPrs from the perspective of cellular and molecular determinants of their pharmacological diversity. Thus, DOPr ligands are examined in terms of structural and functional variety, DOPrs' capacity to engage a multiplicity of canonical and noncanonical G protein-dependent responses is surveyed, and evidence supporting ligand-specific signaling and regulation is analyzed. Pharmacological DOPr subtypes are examined in light of the ability of DOPr to organize into multimeric arrays and to adopt multiple active conformations as well as differences in ligand kinetics. Current knowledge on DOPr targeting to the membrane is examined as a means of understanding how these receptors are especially active in chronic pain management. Insight into cellular and molecular mechanisms of pharmacological diversity should guide the rational design of more effective, longer-lasting, and better-tolerated opioid analgesics for chronic pain management.
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Affiliation(s)
- Louis Gendron
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Catherine M Cahill
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Mark von Zastrow
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Peter W Schiller
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Graciela Pineyro
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
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14
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Li L, Luo HS. G-Protein Signaling Protein-17 (RGS17) Is Upregulated and Promotes Tumor Growth and Migration in Human Colorectal Carcinoma. Oncol Res 2017; 26:27-35. [PMID: 28337960 PMCID: PMC7844555 DOI: 10.3727/096504017x14900515946914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Colorectal carcinoma is one of the leading causes of cancer-related deaths and has a high tendency for metastasis, which makes it a priority to find novel methods to diagnose and treat colorectal carcinoma at a very early stage. We studied the role of the regulator of G-protein signaling (RGS) family of proteins RGS17 in colorectal carcinoma growth and metastasis. We found that RGS17 was upregulated in both clinical colorectal carcinoma tissues and cultured colorectal carcinoma cells. Knockdown of RGS17 by specific siRNA decreased the cell proliferation rate, whereas overexpression of RGS17 with expression plasmid increased the rate in cultured cells. Consistently, a mouse model for colorectal carcinoma also showed that depletion of RGS17 significantly inhibited tumor growth in vivo. Moreover, a Transwell assay showed that RGS17 promoted the ability of colorectal carcinoma cells to migrate and invade. These data suggest that RGS17 is overexpressed in colorectal carcinoma and promotes cell proliferation, migration, and invasion.
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Affiliation(s)
- Ling Li
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, P.R. China
| | - He-Sheng Luo
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, P.R. China
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15
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Alcohol and nicotine codependence-associated DNA methylation changes in promoter regions of addiction-related genes. Sci Rep 2017; 7:41816. [PMID: 28165486 PMCID: PMC5292964 DOI: 10.1038/srep41816] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/28/2016] [Indexed: 01/19/2023] Open
Abstract
Altered DNA methylation in addiction-related genes may modify the susceptibility to alcohol or drug dependence (AD or ND). We profiled peripheral blood DNA methylation levels of 384 CpGs in promoter regions of 82 addiction-related genes in 256 African Americans (AAs) (117 cases with AD-ND codependence and 139 controls) and 196 European Americans (103 cases with AD-ND codependence and 93 controls) using Illumina's GoldenGate DNA methylation array assays. AD-ND codependence-associated DNA methylation changes were analyzed using linear mixed-effects models with consideration of batch effects and covariates age, sex, and ancestry proportions. Seventy CpGs (in 41 genes) showed nominally significant associations (P < 0.05) with AD-ND codependence in both AAs and EAs. One CpG (HTR2B cg27531267) was hypomethylated in AA cases (P = 7.2 × 10-5), while 17 CpGs in 16 genes (including HTR2B cg27531267) were hypermethylated in EA cases (5.6 × 10-9 ≤ P ≤ 9.5 × 10-5). Nevertheless, 13 single nucleotide polymorphisms (SNPs) nearby HTR2B cg27531267 and the interaction of these SNPs and cg27531267 did not show significant effects on AD-ND codependence in either AAs or EAs. Our study demonstrated that DNA methylation changes in addiction-related genes could be potential biomarkers for AD-ND co-dependence. Future studies need to explore whether DNA methylation alterations influence the risk of AD-ND codependence or the other way around.
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16
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Budnik I, Shenkman B, Savion N. Role of G protein signaling in the formation of the fibrin(ogen)–integrin αIIbβ3–actin cytoskeleton complex in platelets. Platelets 2016; 27:563-75. [DOI: 10.3109/09537104.2016.1147544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ivan Budnik
- Goldschleger Eye Research Institute and the Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Pathophysiology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Boris Shenkman
- National Hemophilia Center, Sheba Medical Center, Tel-Hashomer, Israel
| | - Naphtali Savion
- Goldschleger Eye Research Institute and the Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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17
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Hayes MP, Roman DL. Regulator of G Protein Signaling 17 as a Negative Modulator of GPCR Signaling in Multiple Human Cancers. AAPS JOURNAL 2016; 18:550-9. [PMID: 26928451 DOI: 10.1208/s12248-016-9894-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/15/2016] [Indexed: 02/08/2023]
Abstract
Regulators of G protein signaling (RGS) proteins modulate G protein-coupled receptor (GPCR) signaling networks by terminating signals produced by active Gα subunits. RGS17, a member of the RZ subfamily of RGS proteins, is typically only expressed in appreciable amounts in the human central nervous system, but previous works have shown that RGS17 expression is selectively upregulated in a number of malignancies, including lung, breast, prostate, and hepatocellular carcinoma. In addition, this upregulation of RGS17 is associated with a more aggressive cancer phenotype, as increased proliferation, migration, and invasion are observed. Conversely, decreased RGS17 expression diminishes the response of ovarian cancer cells to agents commonly used during chemotherapy. These somewhat contradictory roles of RGS17 in cancer highlight the need for selective, high-affinity inhibitors of RGS17 to use as chemical probes to further the understanding of RGS17 biology. Based on current evidence, these compounds could potentially have clinical utility as novel chemotherapeutics in the treatment of lung, prostate, breast, and liver cancers. Recent advances in screening technologies to identify potential inhibitors coupled with increasing knowledge of the structural requirements of RGS-Gα protein-protein interaction inhibitors make the future of drug discovery efforts targeting RGS17 promising. This review highlights recent findings related to RGS17 as both a canonical and atypical RGS protein, its role in various human disease states, and offers insights on small molecule inhibition of RGS17.
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Affiliation(s)
- Michael P Hayes
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa, USA
| | - David L Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa, USA. .,Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA. .,, 115 S. Grand Avenue, S327 PHAR, Iowa City, Iowa, 52242, USA.
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18
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Taylor VG, Bommarito PA, Tesmer JJG. Structure of the Regulator of G Protein Signaling 8 (RGS8)-Gαq Complex: MOLECULAR BASIS FOR Gα SELECTIVITY. J Biol Chem 2016; 291:5138-45. [PMID: 26755720 DOI: 10.1074/jbc.m115.712075] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling (RGS) proteins interact with activated Gα subunits via their RGS domains and accelerate the hydrolysis of GTP. Although the R4 subfamily of RGS proteins generally accepts both Gαi/o and Gαq/11 subunits as substrates, the R7 and R12 subfamilies select against Gαq/11. In contrast, only one RGS protein, RGS2, is known to be selective for Gαq/11. The molecular basis for this selectivity is not clear. Previously, the crystal structure of RGS2 in complex with Gαq revealed a non-canonical interaction that could be due to interfacial differences imposed by RGS2, the Gα subunit, or both. To resolve this ambiguity, the 2.6 Å crystal structure of RGS8, an R4 subfamily member, was determined in complex with Gαq. RGS8 adopts the same pose on Gαq as it does when bound to Gαi3, indicating that the non-canonical interaction of RGS2 with Gαq is due to unique features of RGS2. Based on the RGS8-Gαq structure, residues in RGS8 that contact a unique α-helical domain loop of Gαq were converted to those typically found in R12 subfamily members, and the reverse substitutions were introduced into RGS10, an R12 subfamily member. Although these substitutions perturbed their ability to stimulate GTP hydrolysis, they did not reverse selectivity. Instead, selectivity for Gαq seems more likely determined by whether strong contacts can be maintained between α6 of the RGS domain and Switch III of Gαq, regions of high sequence and conformational diversity in both protein families.
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Affiliation(s)
- Veronica G Taylor
- From the Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, and the Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109
| | - Paige A Bommarito
- From the Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, and
| | - John J G Tesmer
- From the Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, and
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19
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Hu Y, Xing J, Chen L, Zheng Y, Zhou Z. RGS22 inhibits pancreatic adenocarcinoma cell migration through the G12/13 α subunit/F-actin pathway. Oncol Rep 2015; 34:2507-14. [PMID: 26323264 DOI: 10.3892/or.2015.4209] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 07/27/2015] [Indexed: 11/05/2022] Open
Abstract
Pancreatic cancer is characterized by the potential for local invasion, allowing it to spread during the early developmental stages of the disease. Regulator of G protein signaling 22 (RGS22) localizes to the cytoplasm in pancreatic adenocarcinoma tissue. We overexpressed RGS22 in the human pancreatic cancer cell line BXPC-3. Cells that overexpressed RGS22 had much lower wound-healing rates and greatly reduced migration compared to the control cells. Conversely, cells in which RGS22 expression had been downregulated had higher wound-healing rates and migration than the control cells. These results confirmed that RGS22 expression suppresses pancreatic adenocarcinoma cell migration. Pull-down and coimmunoprecipitation assays revealed that RGS22 had specific interactions with the heterotrimeric G protein G12 α subunit (GNA12) and GNA13 in the cells. We also demonstrated that in the presence of higher RGS22 expression, the cell deformation and F-actin formation caused by lysophosphatidic acid treatment, is delayed. Constitutively active Gα subunits did not accelerate GTP hydrolysis to GDP. We did not investigate the function of RGS22 as a negative regulator of heterotrimeric G12/13 protein signaling. Our data demonstrate that RGS22 acts as a tumor suppressor, repressing human pancreatic adenocarcinoma cell migration by coupling to GNA12/13, which in turn leads to inhibition of stress fiber formation.
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Affiliation(s)
- Yanqiu Hu
- Reproductive Medicine Center, Subei People's Hospital, Yangzhou University, Yangzhou, Jiangsu 225001, P.R. China
| | - Jun Xing
- Reproductive Medicine Center, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, P.R. China
| | - Ling Chen
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Ying Zheng
- Department of Histology and Embryology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, P.R. China
| | - Zuomin Zhou
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
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20
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Woodard GE, Jardín I, Berna-Erro A, Salido GM, Rosado JA. Regulators of G-protein-signaling proteins: negative modulators of G-protein-coupled receptor signaling. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:97-183. [PMID: 26008785 DOI: 10.1016/bs.ircmb.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Regulators of G-protein-signaling (RGS) proteins are a category of intracellular proteins that have an inhibitory effect on the intracellular signaling produced by G-protein-coupled receptors (GPCRs). RGS along with RGS-like proteins switch on through direct contact G-alpha subunits providing a variety of intracellular functions through intracellular signaling. RGS proteins have a common RGS domain that binds to G alpha. RGS proteins accelerate GTPase and thus enhance guanosine triphosphate hydrolysis through the alpha subunit of heterotrimeric G proteins. As a result, they inactivate the G protein and quickly turn off GPCR signaling thus terminating the resulting downstream signals. Activity and subcellular localization of RGS proteins can be changed through covalent molecular changes to the enzyme, differential gene splicing, and processing of the protein. Other roles of RGS proteins have shown them to not be solely committed to being inhibitors but behave more as modulators and integrators of signaling. RGS proteins modulate the duration and kinetics of slow calcium oscillations and rapid phototransduction and ion signaling events. In other cases, RGS proteins integrate G proteins with signaling pathways linked to such diverse cellular responses as cell growth and differentiation, cell motility, and intracellular trafficking. Human and animal studies have revealed that RGS proteins play a vital role in physiology and can be ideal targets for diseases such as those related to addiction where receptor signaling seems continuously switched on.
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Affiliation(s)
- Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Isaac Jardín
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - A Berna-Erro
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Gines M Salido
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Caceres, Spain
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21
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Zhao P, Nunn C, Ramineni S, Hepler JR, Chidiac P. The Ras-binding domain region of RGS14 regulates its functional interactions with heterotrimeric G proteins. J Cell Biochem 2014; 114:1414-23. [PMID: 23255434 DOI: 10.1002/jcb.24483] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 12/06/2012] [Indexed: 12/28/2022]
Abstract
RGS14 is a 60 kDa protein that contains a regulator of G protein signaling (RGS) domain near its N-terminus, a central region containing a pair of tandem Ras-binding domains (RBD), and a GPSM (G protein signaling modulator) domain (a.k.a. Gi/o-Loco binding [GoLoco] motif) near its C-terminus. The RGS domain of RGS14 exhibits GTPase accelerating protein (GAP) activity toward Gαi/o proteins, while its GPSM domain acts as a guanine nucleotide dissociation inhibitor (GDI) on Gαi1 and Gαi3. In the current study, we investigate the contribution of different domains of RGS14 to its biochemical functions. Here we show that the full-length protein has a greater GTPase activating activity but a weaker inhibition of nucleotide dissociation relative to its isolated RGS and GPSM regions, respectively. Our data suggest that these differences may be attributable to an inter-domain interaction within RGS14 that promotes the activity of the RGS domain, but simultaneously inhibits the activity of the GPSM domain. The RBD region seems to play an essential role in this regulatory activity. Moreover, this region of RGS14 is also able to bind to members of the B/R4 subfamily of RGS proteins and enhance their effects on GPCR-activated Gi/o proteins. Overall, our results suggest a mechanism wherein the RBD region associates with the RGS domain region, producing an intramolecular interaction within RGS14 that enhances the GTPase activating function of its RGS domain while disfavoring the negative effect of its GPSM domain on nucleotide dissociation.
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Affiliation(s)
- Peishen Zhao
- Department of Physiology, University of Western Ontario, London, Ontario, Canada
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22
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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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23
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Bodle CR, Mackie DI, Roman DL. RGS17: an emerging therapeutic target for lung and prostate cancers. Future Med Chem 2013; 5:995-1007. [PMID: 23734683 PMCID: PMC3865709 DOI: 10.4155/fmc.13.91] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Ligands for G-protein-coupled receptors (GPCRs) represent approximately 50% of currently marketed drugs. RGS proteins modulate heterotrimeric G proteins and, thus, GPCR signaling, by accelerating the intrinsic GTPase activity of the Gα subunit. Given the prevalence of GPCR targeted therapeutics and the role RGS proteins play in G protein signaling, some RGS proteins are emerging as targets in their own right. One such RGS protein is RGS17. Increased RGS17 expression in some prostate and lung cancers has been demonstrated to support cancer progression, while reduced expression of RGS17 can lead to development of chemotherapeutic resistance in ovarian cancer. High-throughput screening is a powerful tool for lead compound identification, and utilization of high-throughput technologies has led to the discovery of several RGS inhibitors, thus far. As screening technologies advance, the identification of novel lead compounds the subsequent development of targeted therapeutics appears promising.
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Affiliation(s)
- Christopher R Bodle
- The Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
- Division of Medicinal & Natural Products Chemistry, University of Iowa, College of Pharmacy, Iowa City, IA, USA
| | - Duncan I Mackie
- The Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
- Division of Medicinal & Natural Products Chemistry, University of Iowa, College of Pharmacy, Iowa City, IA, USA
- Cancer Signaling and Experimental Therapeutics Program, The Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - David L Roman
- The Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa, College of Pharmacy, Iowa City, IA, USA
- Division of Medicinal & Natural Products Chemistry, University of Iowa, College of Pharmacy, Iowa City, IA, USA
- Cancer Signaling and Experimental Therapeutics Program, The Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
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Nitric Oxide and Zinc-Mediated Protein Assemblies Involved in Mu Opioid Receptor Signaling. Mol Neurobiol 2013; 48:769-82. [DOI: 10.1007/s12035-013-8465-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/18/2013] [Indexed: 01/06/2023]
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Monroy CA, Mackie DI, Roman DL. A high throughput screen for RGS proteins using steady state monitoring of free phosphate formation. PLoS One 2013; 8:e62247. [PMID: 23626793 PMCID: PMC3633906 DOI: 10.1371/journal.pone.0062247] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 03/19/2013] [Indexed: 11/30/2022] Open
Abstract
G-protein coupled receptors are a diverse group that are the target of over 50% of marketed drugs. Activation of these receptors results in the exchange of bound GDP for GTP in the Gα subunit of the heterotrimeric G-protein. The Gα subunit dissociates from the β/γ subunits and both proceed to affect downstream signaling targets. The signal terminates by the hydrolysis of GTP to GDP and is temporally regulated by Regulators of G-protein Signaling (RGS) proteins that act as GTPase Activating Proteins (GAPs). This makes RGS proteins potentially desirable targets for “tuning” the effects of current therapies as well as developing novel pharmacotherapies. Current methods for evaluating RGS activity depend on laborious and/or expensive techniques. In this study we developed a simple and inexpensive assay for the steady state analysis of RGS protein GAP activity, using RGS4, RGS8 and RGS17 as models. Additionally, we report the use of RGS4 as a model for high throughput assay development. After initial setup, this assay can be conducted in a highly parallel fashion with a read time of less than 8 minutes for a 1536-well plate. The assay exhibited a robust Z-factor of 0.6 in a 1536-well plate. We conducted a pilot screen for inhibitors using a small, 2320 compound library. From this screen, 13 compounds were identified as compounds for further analysis. The successful development of this assay for high-throughput screening provides a low cost, high speed, simple method for assessing RGS protein activity.
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Affiliation(s)
- C. Aaron Monroy
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, United States of America
| | - Duncan I. Mackie
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, United States of America
| | - David L. Roman
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, United States of America
- Cancer Signaling and Experimental Therapeutics Program, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States of America
- * E-mail:
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Structure based energy calculation to determine the regulation of G protein signalling by RGS and RGS-G protein interaction specificity. Interdiscip Sci 2013; 4:173-82. [DOI: 10.1007/s12539-012-0130-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/19/2012] [Accepted: 04/12/2012] [Indexed: 01/11/2023]
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Zhao P, Cladman W, Van Tol HHM, Chidiac P. Fine-tuning of GPCR signals by intracellular G protein modulators. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:421-53. [PMID: 23415100 DOI: 10.1016/b978-0-12-394587-7.00010-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Heterotrimeric G proteins convey receptor signals to intracellular effectors. Superimposed over the basic GPCR-G protein-effector scheme are three types of auxiliary proteins that also modulate Gα. Regulator of G protein signaling proteins and G protein signaling modifier proteins respectively promote GTPase activity and hinder GTP/GDP exchange to limit Gα activation. There are also diverse proteins that, like GPCRs, can promote nucleotide exchange and thus activation. Here we review the impact of these auxiliary proteins on GPCR signaling. Although their precise physiological functions are not yet clear, all of them can produce significant effects in experimental systems. These signaling changes are generally consistent with established effects on isolated Gα; however, the activation state of Gα is seldom verified and many such changes appear also to reflect the physical disruption of or indirect effects on interactions between Gα and its associated GPCR, Gβγ, and/or effector.
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Affiliation(s)
- Peishen Zhao
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
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Sánchez-Blázquez P, Rodríguez-Muñoz M, Bailón C, Garzón J. GPCRs promote the release of zinc ions mediated by nNOS/NO and the redox transducer RGSZ2 protein. Antioxid Redox Signal 2012; 17:1163-77. [PMID: 22563771 DOI: 10.1089/ars.2012.4517] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIMS Morphine signaling via the μ-opioid receptor (MOR) is coupled to redox-dependent zinc release from endogenous stores. Thus, MOR activation stimulates the complex formed by RGSZ2 (a regulator of G protein signaling) and neural nitric oxide synthase (nNOS) to produce NO, and to recruit PKCγ and Raf-1 in a zinc-dependent manner. Accordingly, we investigated whether redox regulation of zinc metabolism was unique to the MOR, or if it is a signaling mechanism shared by G-protein coupled receptors (GPCRs). RESULTS A physical interaction with the RGSZ2-nNOS complex was detected for the following GPCRs: neuropeptides, MOR and δ-opioid (DOR); biogenic amines, 5HT1A, 5HT2A, α2A, D1 and D2; acetylcholine, muscarinic M2 and M4; excitatory amino acid glutamate, mGlu2 and mGlu5; and derivatives of arachidonic acid (anandamide), CB1. Agonist activation of these receptors induced the release of zinc ions from the RGSZ2 zinc finger via a nNOS/NO-dependent mechanism, recruiting PKCγ and Raf-1 to the C terminus or the third internal loop of the GPCR. INNOVATION A series of GPCRs share an unexpected mechanistic feature, the nNOS/NO-dependent regulation of zinc ion signaling via a redox mechanism. The RGSZ2 protein emerges as a potential redox zinc switch that converts NO signals into zinc signals, thereby able to modulate the function of redox sensor proteins like PKCγ or Raf-1. CONCLUSION Redox mechanisms are crucial for the successful propagation of GPCR signals in neurons. Thus, dysfunctions of GPCR-regulated NO/zinc signaling may contribute to neurodegenerative and mood disorders such as Alzheimer's disease and depression.
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Stewart A, Huang J, Fisher RA. RGS Proteins in Heart: Brakes on the Vagus. Front Physiol 2012; 3:95. [PMID: 22685433 PMCID: PMC3368389 DOI: 10.3389/fphys.2012.00095] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/27/2012] [Indexed: 12/14/2022] Open
Abstract
It has been nearly a century since Otto Loewi discovered that acetylcholine (ACh) release from the vagus produces bradycardia and reduced cardiac contractility. It is now known that parasympathetic control of the heart is mediated by ACh stimulation of G(i/o)-coupled muscarinic M2 receptors, which directly activate G protein-coupled inwardly rectifying potassium (GIRK) channels via Gβγ resulting in membrane hyperpolarization and inhibition of action potential (AP) firing. However, expression of M2R-GIRK signaling components in heterologous systems failed to recapitulate native channel gating kinetics. The missing link was identified with the discovery of regulator of G protein signaling (RGS) proteins, which act as GTPase-activating proteins to accelerate the intrinsic GTPase activity of Gα resulting in termination of Gα- and Gβγ-mediated signaling to downstream effectors. Studies in mice expressing an RGS-insensitive Gα(i2) mutant (G184S) implicated endogenous RGS proteins as key regulators of parasympathetic signaling in heart. Recently, two RGS proteins have been identified as critical regulators of M2R signaling in heart. RGS6 exhibits a uniquely robust expression in heart, especially in sinoatrial (SAN) and atrioventricular nodal regions. Mice lacking RGS6 exhibit increased bradycardia and inhibition of SAN AP firing in response to CCh as well as a loss of rapid activation and deactivation kinetics and current desensitization for ACh-induced GIRK current (I(KACh)). Similar findings were observed in mice lacking RGS4. Thus, dysregulation in RGS protein expression or function may contribute to pathologies involving aberrant electrical activity in cardiac pacemaker cells. Moreover, RGS6 expression was found to be up-regulated in heart under certain pathological conditions, including doxorubicin treatment, which is known to cause life-threatening cardiotoxicity and atrial fibrillation in cancer patients. On the other hand, increased vagal tone may be cardioprotective in heart failure where acetylcholinesterase inhibitors and vagal stimulation have been proposed as potential therapeutics. Together, these studies identify RGS proteins, especially RGS6, as new therapeutic targets for diseases such as sick sinus syndrome or other maladies involving abnormal autonomic control of the heart.
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Affiliation(s)
- Adele Stewart
- Department of Pharmacology, Carver College of Medicine, University of Iowa Iowa City, IA, USA
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Garzón J, Rodríguez-Muñoz M, Vicente-Sánchez A, García-López MÁ, Martínez-Murillo R, Fischer T, Sánchez-Blázquez P. SUMO-SIM interactions regulate the activity of RGSZ2 proteins. PLoS One 2011; 6:e28557. [PMID: 22163035 PMCID: PMC3232247 DOI: 10.1371/journal.pone.0028557] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 11/10/2011] [Indexed: 11/18/2022] Open
Abstract
The RGSZ2 gene, a regulator of G protein signaling, has been implicated in cognition, Alzheimer's disease, panic disorder, schizophrenia and several human cancers. This 210 amino acid protein is a GTPase accelerating protein (GAP) on Gαi/o/z subunits, binds to the N terminal of neural nitric oxide synthase (nNOS) negatively regulating the production of nitric oxide, and binds to the histidine triad nucleotide-binding protein 1 at the C terminus of different G protein-coupled receptors (GPCRs). We now describe a novel regulatory mechanism of RGS GAP function through the covalent incorporation of Small Ubiquitin-like MOdifiers (SUMO) into RGSZ2 RGS box (RH) and the SUMO non covalent binding with SUMO-interacting motifs (SIM): one upstream of the RH and a second within this region. The covalent attachment of SUMO does not affect RGSZ2 binding to GPCR-activated GαGTP subunits but abolishes its GAP activity. By contrast, non-covalent binding of SUMO with RH SIM impedes RGSZ2 from interacting with GαGTP subunits. Binding of SUMO to the RGSZ2 SIM that lies outside the RH does not affect GαGTP binding or GAP activity, but it could lead to regulatory interactions with sumoylated proteins. Thus, sumoylation and SUMO-SIM interactions constitute a new regulatory mechanism of RGS GAP function and therefore of GPCR cell signaling as well.
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Affiliation(s)
- Javier Garzón
- Cajal Institute, CSIC, Madrid, Spain
- CIBER of Mental Health, ISCIII, Madrid, Spain
| | | | - Ana Vicente-Sánchez
- Cajal Institute, CSIC, Madrid, Spain
- CIBER of Mental Health, ISCIII, Madrid, Spain
| | | | | | - Thierry Fischer
- Department of Immunology and Oncology, National Centre of Biotechnology, CSIC, Madrid, Spain
| | - Pilar Sánchez-Blázquez
- Cajal Institute, CSIC, Madrid, Spain
- CIBER of Mental Health, ISCIII, Madrid, Spain
- * E-mail:
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Abstract
Signal transduction through G-protein-coupled receptors (GPCRs) is central for the regulation of virtually all cellular functions and has been widely implicated in human disease. Regulators of G-protein signaling (RGS proteins) belong to a diverse protein family that was originally discovered for their ability to accelerate signal termination in response to GPCR stimulation, thereby reducing the amplitude and duration of GPCR effects. All RGS proteins share a common RGS domain that interacts with G protein α subunits and mediates their biological regulation of GPCR signaling. However, RGS proteins differ widely in size and the organization of their sequences flanking the RGS domain, which contain several additional functional domains that facilitate protein-protein (or protein-lipid) interactions. RGS proteins are subject to posttranslational modifications, and, in addition, their expression, activity, and subcellular localization can be dynamically regulated. Thus, there exists a wide array of mechanisms that facilitate their proper function as modulators and integrators of G-protein signaling. Several RGS proteins have been implicated in the cardiac remodeling response and heart rate regulation, and changes in RGS protein expression and/or function are believed to participate in the pathophysiology of cardiac hypertrophy, failure and arrhythmias as well as hypertension. This review is based on recent advances in our understanding of the expression pattern, regulation, and functional role of canonical RGS proteins, with a special focus on the healthy heart and the diseased heart. In addition, we discuss their potential and promise as therapeutic targets as well as strategies to modulate their expression and function.
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Affiliation(s)
- Peng Zhang
- Cardiovascular Research Center, Rhode Island Hospital and Alpert Medical School of Brown University, 1 Hoppin St, Providence, RI 02903, USA
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Xie K, Martemyanov KA. Control of striatal signaling by g protein regulators. Front Neuroanat 2011; 5:49. [PMID: 21852966 PMCID: PMC3151604 DOI: 10.3389/fnana.2011.00049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 07/23/2011] [Indexed: 12/03/2022] Open
Abstract
Signaling via heterotrimeric G proteins plays a crucial role in modulating the responses of striatal neurons that ultimately shape core behaviors mediated by the basal ganglia circuitry, such as reward valuation, habit formation, and movement coordination. Activation of G protein-coupled receptors (GPCRs) by extracellular signals activates heterotrimeric G proteins by promoting the binding of GTP to their α subunits. G proteins exert their effects by influencing the activity of key effector proteins in this region, including ion channels, second messenger enzymes, and protein kinases. Striatal neurons express a staggering number of GPCRs whose activation results in the engagement of downstream signaling pathways and cellular responses with unique profiles but common molecular mechanisms. Studies over the last decade have revealed that the extent and duration of GPCR signaling are controlled by a conserved protein family named regulator of G protein signaling (RGS). RGS proteins accelerate GTP hydrolysis by the α subunits of G proteins, thus promoting deactivation of GPCR signaling. In this review, we discuss the progress made in understanding the roles of RGS proteins in controlling striatal G protein signaling and providing integration and selectivity of signal transmission. We review evidence on the formation of a macromolecular complex between RGS proteins and other components of striatal signaling pathways, their molecular regulatory mechanisms and impacts on GPCR signaling in the striatum obtained from biochemical studies and experiments involving genetic mouse models. Special emphasis is placed on RGS9-2, a member of the RGS family that is highly enriched in the striatum and plays critical roles in drug addiction and motor control.
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Affiliation(s)
- Keqiang Xie
- The Scripps Research Institute Jupiter, FL, USA
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Mackie DI, Roman DL. Development of a novel high-throughput screen and identification of small-molecule inhibitors of the Gα-RGS17 protein-protein interaction using AlphaScreen. ACTA ACUST UNITED AC 2011; 16:869-77. [PMID: 21680864 DOI: 10.1177/1087057111410427] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In this study, the authors used AlphaScreen technology to develop a high-throughput screening method for interrogating small-molecule libraries for inhibitors of the Gα(o)-RGS17 interaction. RGS17 is implicated in the growth, proliferation, metastasis, and the migration of prostate and lung cancers. RGS17 is upregulated in lung and prostate tumors up to a 13-fold increase over patient-matched normal tissues. Studies show RGS17 knockdown inhibits colony formation and decreases tumorigenesis in nude mice. The screen in this study uses a measurement of the Gα(o)-RGS17 protein-protein interaction, with an excellent Z score exceeding 0.73, a signal-to-noise ratio >70, and a screening time of 1100 compounds per hour. The authors screened the NCI Diversity Set II and determined 35 initial hits, of which 16 were confirmed after screening against controls. The 16 compounds exhibited IC(50) <10 µM in dose-response experiments. Four exhibited IC(50) values <6 µM while inhibiting the Gα(o)-RGS17 interaction >50% when compared to a biotinylated glutathione-S-transferase control. This report describes the first high-throughput screen for RGS17 inhibitors, as well as a novel paradigm adaptable to many other RGS proteins, which are emerging as attractive drug targets for modulating G-protein-coupled receptor signaling.
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Affiliation(s)
- Duncan I Mackie
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, 115 South Grand Avenue, Iowa City, IA 52242, USA
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Liu AM, Lo RK, Guo EX, Ho MK, Ye RD, Wong YH. Gα16 interacts with tetratricopeptide repeat 1 (TPR1) through its β3 region to activate Ras independently of phospholipase Cβ signaling. BMC STRUCTURAL BIOLOGY 2011; 11:17. [PMID: 21486497 PMCID: PMC3098143 DOI: 10.1186/1472-6807-11-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 04/13/2011] [Indexed: 12/02/2022]
Abstract
Background G protein-coupled receptors constitute the largest family of cell surface receptors in the mammalian genome. As the core of the G protein signal transduction machinery, the Gα subunits are required to interact with multiple partners. The GTP-bound active state of many Gα subunits can bind a multitude of effectors and regulatory proteins. Yet it remains unclear if the different proteins utilize distinct or common structural motifs on the Gα subunit for binding. Using Gα16 as a model, we asked if its recently discovered adaptor protein tetratricopeptide repeat 1 (TPR1) binds to the same region as its canonical effector, phospholipase Cβ (PLCβ). Results We have examined the specificity of Gα16/TPR1 association by testing a series of chimeras between Gα16 and Gαz. TPR1 co-immunoprecipitated with Gα16 and more tightly with its constitutively active Gα16QL, but not Gαz. Progressive replacement of Gα16 sequence with the corresponding residues of Gαz eventually identified a stretch of six amino acids in the β3 region of Gα16 which are responsible for TPR1 interaction and the subsequent Ras activation. Insertion of these six residues into Gαz allowed productive TPR1-interaction. Since the β3 region only minimally contributes to interact with PLCβ, several chimeras exhibited differential abilities to stimulate PLCβ and Ras. The ability of the chimeras to activate downstream transcription factors such as signal transducer and activator of transcription 3 and nuclear factor κB appeared to be associated with PLCβ signaling. Conclusions Our results suggest that Gα16 can signal through TPR1/Ras and PLCβ simultaneously and independently. The β3 region of Gα16 is essential for interaction with TPR1 and the subsequent activation of Ras, but has relatively minor influence on the PLCβ interaction. Gα16 may utilize different structural domains to bind TPR1 and PLCβ.
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Affiliation(s)
- Andrew Mf Liu
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Hadjighassem MR, Galaraga K, Albert PR. Freud-2/CC2D1B mediates dual repression of the serotonin-1A receptor gene. Eur J Neurosci 2010; 33:214-23. [PMID: 21155902 DOI: 10.1111/j.1460-9568.2010.07498.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The serotonin-1A (5-HT1A) receptor functions as a pre-synaptic autoreceptor in serotonin neurons that regulates their activity, and is also widely expressed on non-serotonergic neurons as a post-synaptic heteroreceptor to mediate serotonin action. The 5-HT1A receptor gene is strongly repressed by a dual repressor element (DRE), which is recognized by two proteins: Freud-1/CC2D1A and another unknown protein. Here we identify mouse Freud-2/CC2D1B as the second repressor of the 5-HT1A-DRE. Freud-2 shares 50% amino acid identity with Freud-1, and contains conserved structural domains. Mouse Freud-2 bound specifically to the rat 5-HT1A-DRE adjacent to, and partially overlapping, the Freud-1 binding site. By supershift assay using nuclear extracts from L6 myoblasts, Freud-2-DRE complexes were distinguished from Freud-1-DRE complexes. Freud-2 mRNA and protein were detected throughout mouse brain and peripheral tissues. Freud-2 repressed 5-HT1A promoter-reporter constructs in a DRE-dependent manner in non-neuronal (L6) or 5-HT1A-expressing neuronal (NG108-15, RN46A) cell models. In NG108-15 cells, knockdown of Freud-2 using a specific short-interfering RNA reduced endogenous Freud-2 protein levels and decreased Freud-2 bound to the 5-HT1A-DRE as detected by chromatin immunoprecipitation assay, but increased 5-HT1A promoter activity and 5-HT1A protein levels. Taken together, these data show that Freud-2 is the second component that, with Freud-1, mediates dual repression of the 5-HT1A receptor gene at the DRE.
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Affiliation(s)
- Mahmoud R Hadjighassem
- Ottawa Hospital Research Institute (Neuroscience) and Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada K1H 8M5
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Hooks SB, Callihan P, Altman MK, Hurst JH, Ali MW, Murph MM. Regulators of G-Protein signaling RGS10 and RGS17 regulate chemoresistance in ovarian cancer cells. Mol Cancer 2010; 9:289. [PMID: 21044322 PMCID: PMC2988731 DOI: 10.1186/1476-4598-9-289] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 11/02/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A critical therapeutic challenge in epithelial ovarian carcinoma is the development of chemoresistance among tumor cells following exposure to first line chemotherapeutics. The molecular and genetic changes that drive the development of chemoresistance are unknown, and this lack of mechanistic insight is a major obstacle in preventing and predicting the occurrence of refractory disease. We have recently shown that Regulators of G-protein Signaling (RGS) proteins negatively regulate signaling by lysophosphatidic acid (LPA), a growth factor elevated in malignant ascites fluid that triggers oncogenic growth and survival signaling in ovarian cancer cells. The goal of this study was to determine the role of RGS protein expression in ovarian cancer chemoresistance. RESULTS In this study, we find that RGS2, RGS5, RGS10 and RGS17 transcripts are expressed at significantly lower levels in cells resistant to chemotherapy compared with parental, chemo-sensitive cells in gene expression datasets of multiple models of chemoresistance. Further, exposure of SKOV-3 cells to cytotoxic chemotherapy causes acute, persistent downregulation of RGS10 and RGS17 transcript expression. Direct inhibition of RGS10 or RGS17 expression using siRNA knock-down significantly reduces chemotherapy-induced cell toxicity. The effects of cisplatin, vincristine, and docetaxel are inhibited following RGS10 and RGS17 knock-down in cell viability assays and phosphatidyl serine externalization assays in SKOV-3 cells and MDR-HeyA8 cells. We further show that AKT activation is higher following RGS10 knock-down and RGS 10 and RGS17 overexpression blocked LPA mediated activation of AKT, suggesting that RGS proteins may blunt AKT survival pathways. CONCLUSIONS Taken together, our data suggest that chemotherapy exposure triggers loss of RGS10 and RGS17 expression in ovarian cancer cells, and that loss of expression contributes to the development of chemoresistance, possibly through amplification of endogenous AKT signals. Our results establish RGS10 and RGS17 as novel regulators of cell survival and chemoresistance in ovarian cancer cells and suggest that their reduced expression may be diagnostic of chemoresistance.
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Affiliation(s)
- Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA, USA.
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Laliberté B, Wilson AM, Nafisi H, Mao H, Zhou YY, Daigle M, Albert PR. TNFAIP8: a new effector for Galpha(i) coupling to reduce cell death and induce cell transformation. J Cell Physiol 2010; 225:865-74. [PMID: 20607800 DOI: 10.1002/jcp.22297] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Galpha(i)-coupled receptors comprise a diverse family of receptors that induce transformation by largely unknown mechanisms. We previously found that the Galpha(i)-coupled dopamine-D2short (D2S) receptor transforms Balb-D2S cells via Gαi3. To identify new Gαi effectors, a yeast two-hybrid screen was done using constitutively active Gαi3-Q204L as bait, and tumor necrosis factor-alpha (TNFα)-induced protein 8 (TNFAIP8, SCC-S2/NDED/GG2-1) was identified. In contrast, TNFAIP8-related TIPE1 and TIPE2 showed a very weak interaction with Gαi3. In yeast mating, in vitro pull-down, co-immunoprecipitation and bioluminescence resonance energy transfer (BRET) assays, TNFAIP8 preferentially interacted with activated Gαi proteins, consistent with direct Gαi-TNFAIP8 coupling. Over-expression or depletion of TNFAIP8 using antisense constructs in Balb-D2S cells did not affect D2S-induced signaling to Gαi-dependent inhibition of cAMP. In contrast, antisense depletion of TNFAIP8 completely inhibited spontaneous and D2S-induced foci formation, consistent with a role for TNFAIP8 in Gαi-dependent transformation. To address possible mechanisms, the effect of D2S signaling via TNFAIP8 on TNFα action was examined. D2S receptor activation inhibited TNFα-induced cell death in Balb-D2S cells, but not in cells depleted of TNFAIP8. However, depletion of TNFAIP8 did not prevent D2S-induced inhibition of TNFα-mediated caspase activation, suggesting that D2S/TNFAIP8-induced protection from TNFα-induced cell death is caspase-independent. The data suggest that Gαi-TNFAIP8-mediated rescue of pre-oncogenic cells enhances progression to oncogenic transformation, providing a selective target to inhibit cellular transformation.
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Affiliation(s)
- Benoit Laliberté
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, ON, Canada
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Wilkinson KA, Nakamura Y, Henley JM. Targets and consequences of protein SUMOylation in neurons. BRAIN RESEARCH REVIEWS 2010; 64:195-212. [PMID: 20382182 PMCID: PMC3310160 DOI: 10.1016/j.brainresrev.2010.04.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 03/24/2010] [Accepted: 04/01/2010] [Indexed: 11/26/2022]
Abstract
The post-translational modification of proteins is critical for the spatial and temporal regulation of signalling cascades. This is especially important in the CNS where the processes affecting differentiation, growth, targeting and communication between neurones are highly complex and very tightly regulated. In recent years it has emerged that modification of proteins by members of the SUMO (small ubiquitin-related modifier) family of proteins play key roles in neuronal function. SUMOylation involves the covalent conjugation of a member of the SUMO family to lysine residues in target proteins. Multiple nuclear and perinuclear SUMOylation targets have been reported to be involved in nuclear organisation and transcriptional regulation. In addition, a growing number of extranuclear SUMO substrates have been identified that can have important acute effects on neuronal function. The SUMOylation of both intra- and extranuclear proteins have been implicated in a diverse array of processes that have far-reaching implications for neuronal function and pathophysiology. Here we review the current understanding of the targets and consequences of protein SUMOylation in the brain and examine its established and potential involvement in a wide range of neurological and neurodegenerative diseases.
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Affiliation(s)
- Kevin A. Wilkinson
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Yasuko Nakamura
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Jeremy M. Henley
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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Hsa-mir-182 suppresses lung tumorigenesis through down regulation of RGS17 expression in vitro. Biochem Biophys Res Commun 2010; 396:501-7. [DOI: 10.1016/j.bbrc.2010.04.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 04/22/2010] [Indexed: 11/22/2022]
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Zhao P, Nguyen CH, Chidiac P. The proline-rich N-terminal domain of G18 exhibits a novel G protein regulatory function. J Biol Chem 2010; 285:9008-17. [PMID: 20097748 DOI: 10.1074/jbc.m109.057174] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The protein G18 (also known as AGS4 or GPSM3) contains three conserved GoLoco/GPR domains in its central and C-terminal regions that bind to inactive Galpha(i), whereas the N-terminal region has not been previously characterized. We investigated whether this domain might itself regulate G protein activity by assessing the abilities of G18 and mutants thereof to modulate the nucleotide binding and hydrolytic properties of Galpha(i1) and Galpha(o). Surprisingly, in the presence of fluoroaluminate (AlF(4)(-)) both G proteins bound strongly to full-length G18 (G18wt) and to its isolated N-terminal domain (G18DeltaC) but not to its GoLoco region (DeltaNG18). Thus, it appears that its N-terminal domain promotes G18 binding to fluoroaluminate-activated Galpha(i/o). Neither G18wt nor any G18 mutant affected the GTPase activity of Galpha(i1) or Galpha(o). In contrast, complex effects were noted with respect to nucleotide binding. As inferred by the binding of [(35)S]GTPgammaS (guanosine 5'-O-[gamma-thio]triphosphate) to Galpha(i1), the isolated GoLoco region as expected acted as a guanine nucleotide dissociation inhibitor, whereas the N-terminal region exhibited a previously unknown guanine nucleotide exchange factor effect on this G protein. On the other hand, the N terminus inhibited [(35)S]GTPgammaS binding to Galpha(o), albeit to a lesser extent than the effect of the GoLoco region on Galpha(i1). Taken together, our results identify the N-terminal region of G18 as a novel G protein-interacting domain that may have distinct regulatory effects within the G(i/o) subfamily, and thus, it could potentially play a role in differentiating signals between these related G proteins.
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Affiliation(s)
- Peishen Zhao
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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Regulators of G Protein Signaling Proteins as Targets for Drug Discovery. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 91:81-119. [DOI: 10.1016/s1877-1173(10)91004-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Terzi D, Stergiou E, King SL, Zachariou V. Regulators of G protein signaling in neuropsychiatric disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 86:299-333. [PMID: 20374720 DOI: 10.1016/s1877-1173(09)86010-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Regulators of G protein signaling (RGS) comprise a diverse group of about 40 proteins which determine signaling amplitude and duration via modulation of receptor/G protein or receptor/effector coupling. Several members of the RGS family are expressed in the brain, where they have precise roles in regulation of important physiological processes. The unique functions of each RGS can be attributed to its structure, distinct pattern of expression, and regulation, and its preferential interactions with receptors, Galpha subunits and other signaling proteins. Evidence suggests dysfunction of RGS proteins is related to several neuropathological conditions. Moreover, clinical and preclinical work reveals that the efficacy and/or side effects of treatments are highly influenced by RGS activity. This article summarizes findings on RGS proteins in vulnerability to several neuropsychiatric disorders, the mechanism via which RGS proteins control neuronal responses and their potential use as drug targets.
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Affiliation(s)
- Dimitra Terzi
- Department of Pharmacology, Faculty of Medicine, University of Crete, Heraklion 71003, Crete, Greece
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Tesmer JJG. Structure and function of regulator of G protein signaling homology domains. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 86:75-113. [PMID: 20374714 DOI: 10.1016/s1877-1173(09)86004-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
All regulator of G protein signaling (RGS) proteins contain a conserved domain of approximately 130 amino acids that binds to activated heterotrimeric G protein α subunits (Gα) and accelerates their rate of GTP hydrolysis. Homologous domains are found in at least six other protein families, including a family of Rho guanine nucleotide exchange factors (RhoGEFs) and the G protein-coupled receptor kinases (GRKs). Although some of the RhoGEF and GRK RGS-like domains can also bind to activated Gα subunits, they do so in distinct ways and with much lower levels of GTPase activation. In other protein families, the domains have as of yet no obvious relationship to heterotrimeric G protein signaling. These RGS homology (RH) domains are now recognized as mediators of extraordinarily diverse protein-protein interactions. Through these interactions, they play roles that range from enzyme to molecular scaffold to signal transducing module. In this review, the atomic structures of RH domains from RGS proteins, Axins, RhoGEFs, and GRKs are compared in light of what is currently known about their functional roles.
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Affiliation(s)
- John J G Tesmer
- Department of Pharmacology, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109‐2216, USA
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You M, Wang D, Liu P, Vikis H, James M, Lu Y, Wang Y, Wang M, Chen Q, Jia D, Liu Y, Wen W, Yang P, Sun Z, Pinney SM, Zheng W, Shu XO, Long J, Gao YT, Xiang YB, Chow WH, Rothman N, Petersen GM, de Andrade M, Wu Y, Cunningham JM, Wiest JS, Fain PR, Schwartz AG, Girard L, Gazdar A, Gaba C, Rothschild H, Mandal D, Coons T, Lee J, Kupert E, Seminara D, Minna J, Bailey-Wilson JE, Amos CI, Anderson MW. Fine mapping of chromosome 6q23-25 region in familial lung cancer families reveals RGS17 as a likely candidate gene. Clin Cancer Res 2009; 15:2666-74. [PMID: 19351763 PMCID: PMC2746091 DOI: 10.1158/1078-0432.ccr-08-2335] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we further refined this locus to identify a single candidate gene, by fine mapping using microsatellite markers and association studies using high-density single nucleotide polymorphisms (SNP). EXPERIMENTAL DESIGN Six multigenerational families with five or more affected members were chosen for fine-mapping the 6q linkage region using microsatellite markers. For association mapping, we genotyped 24 6q-linked cases and 72 unrelated noncancer controls from the Genetic Epidemiology of Lung Cancer Consortium resources using the Affymetrix 500K chipset. Significant associations were validated in two independent familial lung cancer populations: 226 familial lung cases and 313 controls from the Genetic Epidemiology of Lung Cancer Consortium, and 154 familial cases and 325 controls from Mayo Clinic. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. RESULTS A region-wide scan across 6q23-25 found significant association between lung cancer susceptibility and three single nucleotide polymorphisms in the first intron of the RGS17 gene. This association was further confirmed in two independent familial lung cancer populations. By quantitative real-time PCR analysis of matched tumor and normal human tissues, we found that RGS17 transcript accumulation is highly and consistently increased in sporadic lung cancers. Human lung tumor cell proliferation and tumorigenesis in nude mice are inhibited upon knockdown of RGS17 levels. CONCLUSION RGS17 is a major candidate for the familial lung cancer susceptibility locus on chromosome 6q23-25.
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Affiliation(s)
- Ming You
- Washington University, St. Louis, Missouri 63110, USA.
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RNAi methodologies for the functional study of signaling molecules. PLoS One 2009; 4:e4559. [PMID: 19238203 PMCID: PMC2641016 DOI: 10.1371/journal.pone.0004559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 01/13/2009] [Indexed: 12/25/2022] Open
Abstract
RNA interference (RNAi) was investigated with the aim of achieving gene silencing with diverse RNAi platforms that include small interfering RNA (siRNA), short hairpin RNA (shRNA) and antisense oligonucleotides (ASO). Different versions of each system were used to silence the expression of specific subunits of the heterotrimeric signal transducing G-proteins, G alpha i2 and G beta 2, in the RAW 264.7 murine macrophage cell line. The specificity of the different RNA interference (RNAi) platforms was assessed by DNA microarray analysis. Reliable RNAi methodologies against the genes of interest were then developed and applied to functional studies of signaling networks. This study demonstrates a successful knockdown of target genes and shows the potential of RNAi for use in functional studies of signaling molecules.
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James MA, Lu Y, Liu Y, Vikis HG, You M. RGS17, an overexpressed gene in human lung and prostate cancer, induces tumor cell proliferation through the cyclic AMP-PKA-CREB pathway. Cancer Res 2009; 69:2108-16. [PMID: 19244110 DOI: 10.1158/0008-5472.can-08-3495] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have identified RGS17 as a commonly induced gene in lung and prostate tumors. Through microarray and gene expression analysis, we show that expression of RGS17 is up-regulated in 80% of lung tumors, and also up-regulated in prostate tumors. Through knockdown and overexpression of RGS17 in tumor cells, we show that RGS17 confers a proliferative phenotype and is required for the maintenance of the proliferative potential of tumor cells. We show through exon microarray, transcript analysis, and functional assays that RGS17 promotes cyclic AMP (cAMP)-responsive element binding protein (CREB)-responsive gene expression, increases cAMP levels, and enhances forskolin-mediated cAMP production. Furthermore, inhibition of cAMP-dependent kinase prevents tumor cell proliferation, and proliferation is partially rescued by RGS17 overexpression. In the present study, we show a role for RGS17 in the maintenance of tumor cell proliferation through induction of cAMP signaling and CREB phosphorylation. The prevalence of the induction of RGS17 in tumor tissues of various types further implicates its importance in the maintenance of tumor growth.
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Affiliation(s)
- Michael A James
- Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Hu Y, Xing J, Chen L, Guo X, Du Y, Zhao C, Zhu Y, Lin M, Zhou Z, Sha J. RGS22, A Novel Testis-Specific Regulator of G-protein Signaling Involved in Human and Mouse Spermiogenesis along with GNA12/13 Subunits1. Biol Reprod 2008; 79:1021-9. [DOI: 10.1095/biolreprod.107.067504] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Bromberg KD, Iyengar R, He JC. Regulation of neurite outgrowth by G(i/o) signaling pathways. FRONT BIOSCI-LANDMRK 2008; 13:4544-57. [PMID: 18508528 DOI: 10.2741/3022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Neurogenesis is a long and winding journey. A neural progenitor cell migrates long distances, differentiates by forming a single axon and multiple dendrites, undergoes maturation, and ultimately survives. The initial formation of neurites during neuronal differentiation, commonly referred to as "neurite outgrowth," can be induced by a large repertoire of signals that stimulate an array of receptors and downstream signaling pathways. The G(i/o) family of heterotrimeric G-proteins are abundantly expressed in the brain and enriched at neuronal growth cones. Recent evidence has uncovered several G(i/o)-coupled receptors that induce neurite outgrowth and has begun to elucidate the underlying molecular mechanisms. Emerging data suggests that signals from several G(i/o)-coupled receptors converge at the transcription factor STAT3 to regulate neurite outgrowth and at Rac1 and Cdc42 to regulate cytoskeletal reorganization. Physiologically, signaling through G(i/o)-coupled cannabinoid receptors is critical for pro percentral nervous system development. As the mechanisms by which G(i/o)-coupled receptors regulate neurite outgrowth are clarified, it is becoming evident that modulating signals from G(i/o) and their receptors has great potential for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Kenneth D Bromberg
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Charles AL, Chang CK, Wu ML, Huang TC. Studies on the expression of liver detoxifying enzymes in rats fed seaweed (Monostroma nitidum). Food Chem Toxicol 2007; 45:2390-6. [PMID: 17673347 DOI: 10.1016/j.fct.2007.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2006] [Revised: 05/02/2007] [Accepted: 06/10/2007] [Indexed: 11/23/2022]
Abstract
The expression level of phase I (CYP1A1 and CYP1A2) and phase II (GST, and UGT) enzyme-coded genes were measured in liver microsomes of 30 Sprague-Dawley rats fed sea weed (Monostroma nitidum). Quantitative and qualitative analysis of the detoxifying enzymes were investigated using reverse transcription polymerase reaction (RT-PCR) and real time polymerase reaction (Real-time PCR) techniques. The antioxidative properties of seaweed were screened and investigated for its hepatoprotective activity in rat. There was no significant induction of GSTYa1, GSTYa2, and CYP1A2. However, an M. nitidum diet was found to significantly increase UGT1A1 and UGT1A6 mRNA levels and to decrease CYP1A1 mRNA levels in rat liver. Structural studies confirmed the presence of sulfated polysaccharides in the seaweed samples. The results demonstrate the potential of seaweed as a natural source of sulfated polysaccharide substances with potential use in chemoprevention medicine.
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Affiliation(s)
- Albert Linton Charles
- Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology (NPUST), Pingtung 91201, Taiwan, ROC
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Martin S, Wilkinson KA, Nishimune A, Henley JM. Emerging extranuclear roles of protein SUMOylation in neuronal function and dysfunction. Nat Rev Neurosci 2007; 8:948-59. [PMID: 17987030 PMCID: PMC3314512 DOI: 10.1038/nrn2276] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Post-translational protein modifications are integral components of signalling cascades that enable cells to efficiently, rapidly and reversibly respond to extracellular stimuli. These modifications have crucial roles in the CNS, where the communication between neurons is particularly complex. SUMOylation is a post-translational modification in which a member of the small ubiquitin-like modifier (SUMO) family of proteins is conjugated to lysine residues in target proteins. It is well established that SUMOylation controls many aspects of nuclear function, but it is now clear that it is also a key determinant in many extranuclear neuronal processes, and it has also been implicated in a wide range of neuropathological conditions.
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Affiliation(s)
- Stéphane Martin
- MRC Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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