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McNeill SM, Zhao P. The roles of RGS proteins in cardiometabolic disease. Br J Pharmacol 2024; 181:2319-2337. [PMID: 36964984 DOI: 10.1111/bph.16076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/12/2023] [Accepted: 03/20/2023] [Indexed: 03/27/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are the most prominent receptors on the surface of the cell and play a central role in the regulation of cardiac and metabolic functions. GPCRs transmit extracellular stimuli to the interior of the cells by activating one or more heterotrimeric G proteins. The duration and intensity of G protein-mediated signalling are tightly controlled by a large array of intracellular mediators, including the regulator of G protein signalling (RGS) proteins. RGS proteins selectively promote the GTPase activity of a subset of Gα subunits, thus serving as negative regulators in a pathway-dependent manner. In the current review, we summarise the involvement of RGS proteins in cardiometabolic function with a focus on their tissue distribution, mechanisms of action and dysregulation under various disease conditions. We also discuss the potential therapeutic applications for targeting RGS proteins in treating cardiometabolic conditions and current progress in developing RGS modulators. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Samantha M McNeill
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Peishen Zhao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins (CCeMMP), Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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2
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Lin Z, Xie Y, Gongora J, Liu X, Zahn E, Palai BB, Ramirez D, Searfoss RM, Vitorino FN, Dann GP, Zhao C, Han X, MacTaggart B, Lan X, Fu D, Greenberg L, Zhang Y, Lavine KJ, Greenberg MJ, Lv D, Kashina A, Garcia BA. An Unbiased Proteomic Platform for Activity-based Arginylation Profiling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596974. [PMID: 38854050 PMCID: PMC11160793 DOI: 10.1101/2024.06.01.596974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Protein arginylation is an essential posttranslational modification (PTM) catalyzed by arginyl-tRNA-protein transferase 1 (ATE1) in mammalian systems. Arginylation features a post-translational conjugation of an arginyl to a protein, making it extremely challenging to differentiate from translational arginine residues with the same mass in a protein sequence. Here we present a general activity-based arginylation profiling (ABAP) platform for the unbiased discovery of arginylation substrates and their precise modification sites. This method integrates isotopic arginine labeling into an ATE1 assay utilizing biological lysates (ex vivo) rather than live cells, thus eliminating translational bias derived from the ribosomal activity and enabling bona fide arginylation identification using isotopic features. ABAP has been successfully applied to an array of peptide, protein, cell, patient, and animal tissue samples using 20 μg sample input, with 229 unique arginylation sites revealed from human proteomes. Representative sites were validated and followed up for their biological functions. The developed platform is globally applicable to the aforementioned sample types and therefore paves the way for functional studies of this difficult-to-characterize protein modification.
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Affiliation(s)
- Zongtao Lin
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Yixuan Xie
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Joanna Gongora
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Xingyu Liu
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Emily Zahn
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Bibhuti Bhusana Palai
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Daniel Ramirez
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Rick M. Searfoss
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Francisca N. Vitorino
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Geoffrey P. Dann
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
| | - Chenfeng Zhao
- McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63110
| | - Xian Han
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Brittany MacTaggart
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Xin Lan
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Dechen Fu
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Lina Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Yi Zhang
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Kory J. Lavine
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael J. Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
| | - Dongwen Lv
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Anna Kashina
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63110
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Bonnet LV, Palandri A, Flores-Martin JB, Hallak ME. Arginyltransferase 1 modulates p62-driven autophagy via mTORC1/AMPk signaling. Cell Commun Signal 2024; 22:87. [PMID: 38297346 PMCID: PMC10832197 DOI: 10.1186/s12964-024-01499-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/21/2024] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND Arginyltransferase (Ate1) orchestrates posttranslational protein arginylation, a pivotal regulator of cellular proteolytic processes. In eukaryotic cells, two interconnected systems-the ubiquitin proteasome system (UPS) and macroautophagy-mediate proteolysis and cooperate to maintain quality protein control and cellular homeostasis. Previous studies have shown that N-terminal arginylation facilitates protein degradation through the UPS. Dysregulation of this machinery triggers p62-mediated autophagy to ensure proper substrate processing. Nevertheless, how Ate1 operates through this intricate mechanism remains elusive. METHODS We investigated Ate1 subcellular distribution through confocal microscopy and biochemical assays using cells transiently or stably expressing either endogenous Ate1 or a GFP-tagged Ate1 isoform transfected in CHO-K1 or MEFs, respectively. To assess Ate1 and p62-cargo clustering, we analyzed their colocalization and multimerization status by immunofluorescence and nonreducing immunoblotting, respectively. Additionally, we employed Ate1 KO cells to examine the role of Ate1 in autophagy. Ate1 KO MEFs cells stably expressing GFP-tagged Ate1-1 isoform were used as a model for phenotype rescue. Autophagy dynamics were evaluated by analyzing LC3B turnover and p62/SQSTM1 levels under both steady-state and serum-starvation conditions, through immunoblotting and immunofluorescence. We determined mTORC1/AMPk activation by assessing mTOR and AMPk phosphorylation through immunoblotting, while mTORC1 lysosomal localization was monitored by confocal microscopy. RESULTS Here, we report a multifaceted role for Ate1 in the autophagic process, wherein it clusters with p62, facilitates autophagic clearance, and modulates its signaling. Mechanistically, we found that cell-specific inactivation of Ate1 elicits overactivation of the mTORC1/AMPk signaling hub that underlies a failure in autophagic flux and subsequent substrate accumulation, which is partially rescued by ectopic expression of Ate1. Statistical significance was assessed using a two-sided unpaired t test with a significance threshold set at P<0.05. CONCLUSIONS Our findings uncover a critical housekeeping role of Ate1 in mTORC1/AMPk-regulated autophagy, as a potential therapeutic target related to this pathway, that is dysregulated in many neurodegenerative and cancer diseases.
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Affiliation(s)
- Laura V Bonnet
- Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba, Córdoba, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CIQUIBIC, Córdoba, Argentina.
| | - Anabela Palandri
- Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CIQUIBIC, Córdoba, Argentina
| | - Jesica B Flores-Martin
- Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CIQUIBIC, Córdoba, Argentina
| | - Marta E Hallak
- Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba, Córdoba, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CIQUIBIC, Córdoba, Argentina.
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Zubrycka A, Dambire C, Dalle Carbonare L, Sharma G, Boeckx T, Swarup K, Sturrock CJ, Atkinson BS, Swarup R, Corbineau F, Oldham NJ, Holdsworth MJ. ERFVII action and modulation through oxygen-sensing in Arabidopsis thaliana. Nat Commun 2023; 14:4665. [PMID: 37537157 PMCID: PMC10400637 DOI: 10.1038/s41467-023-40366-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 07/25/2023] [Indexed: 08/05/2023] Open
Abstract
Oxygen is a key signalling component of plant biology, and whilst an oxygen-sensing mechanism was previously described in Arabidopsis thaliana, key features of the associated PLANT CYSTEINE OXIDASE (PCO) N-degron pathway and Group VII ETHYLENE RESPONSE FACTOR (ERFVII) transcription factor substrates remain untested or unknown. We demonstrate that ERFVIIs show non-autonomous activation of root hypoxia tolerance and are essential for root development and survival under oxygen limiting conditions in soil. We determine the combined effects of ERFVIIs in controlling gene expression and define genetic and environmental components required for proteasome-dependent oxygen-regulated stability of ERFVIIs through the PCO N-degron pathway. Using a plant extract, unexpected amino-terminal cysteine sulphonic acid oxidation level of ERFVIIs was observed, suggesting a requirement for additional enzymatic activity within the pathway. Our results provide a holistic understanding of the properties, functions and readouts of this oxygen-sensing mechanism defined through its role in modulating ERFVII stability.
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Affiliation(s)
- Agata Zubrycka
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Charlene Dambire
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Laura Dalle Carbonare
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
- Department of Biology, University of Oxford, OX1 3RB, Oxford, UK
| | - Gunjan Sharma
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Tinne Boeckx
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Kamal Swarup
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Craig J Sturrock
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Brian S Atkinson
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Ranjan Swarup
- School of Biosciences, University of Nottingham, LE12 5RD, Loughborough, UK
| | - Françoise Corbineau
- UMR 7622 CNRS-UPMC, Biologie du développement, Institut de Biologie Paris Seine, Sorbonne Université, Paris, France
| | - Neil J Oldham
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Li L, Xu Q, Tang C. RGS proteins and their roles in cancer: friend or foe? Cancer Cell Int 2023; 23:81. [PMID: 37118788 PMCID: PMC10148553 DOI: 10.1186/s12935-023-02932-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 04/30/2023] Open
Abstract
As negative modulators of G-protein-coupled receptors (GPCRs) signaling, regulators of G protein signaling (RGS) proteins facilitate various downstream cellular signalings through regulating kinds of heterotrimeric G proteins by stimulating the guanosine triphosphatase (GTPase) activity of G-protein α (Gα) subunits. The expression of RGS proteins is dynamically and precisely mediated by several different mechanisms including epigenetic regulation, transcriptional regulation -and post-translational regulation. Emerging evidence has shown that RGS proteins act as important mediators in controlling essential cellular processes including cell proliferation, survival -and death via regulating downstream cellular signaling activities, indicating that RGS proteins are fundamentally involved in sustaining normal physiological functions and dysregulation of RGS proteins (such as aberrant expression of RGS proteins) is closely associated with pathologies of many diseases such as cancer. In this review, we summarize the molecular mechanisms governing the expression of RGS proteins, and further discuss the relationship of RGS proteins and cancer.
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Affiliation(s)
- Lin Li
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China
- Department of Urology, Third Affiliated Hospital of the Second Military Medical University, Shanghai, 201805, China
| | - Qiang Xu
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China
| | - Chao Tang
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China.
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Yang X, Cheng K, Wang LY, Jiang JG. The role of endothelial cell in cardiac hypertrophy: Focusing on angiogenesis and intercellular crosstalk. Biomed Pharmacother 2023; 163:114799. [PMID: 37121147 DOI: 10.1016/j.biopha.2023.114799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/02/2023] Open
Abstract
Cardiac hypertrophy is characterized by cardiac structural remodeling, fibrosis, microvascular rarefaction, and chronic inflammation. The heart is structurally organized by different cell types, including cardiomyocytes, fibroblasts, endothelial cells, and immune cells. These cells highly interact with each other by a number of paracrine or autocrine factors. Cell-cell communication is indispensable for cardiac development, but also plays a vital role in regulating cardiac response to damage. Although cardiomyocytes and fibroblasts are deemed as key regulators of hypertrophic stimulation, other cells, including endothelial cells, also exert important effects on cardiac hypertrophy. More particularly, endothelial cells are the most abundant cells in the heart, which make up the basic structure of blood vessels and are widespread around other cells in the heart, implicating the great and inbuilt advantage of intercellular crosstalk. Cardiac microvascular plexuses are essential for transport of liquids, nutrients, molecules and cells within the heart. Meanwhile, endothelial cell-mediated paracrine signals have multiple positive or negative influences on cardiac hypertrophy. However, a comprehensive discussion of these influences and consequences is required. This review aims to summarize the basic function of endothelial cells in angiogenesis, with an emphasis on angiogenic molecules under hypertrophic conditions. The secondary objective of the research is to fully discuss the key molecules involved in the intercellular crosstalk and the endothelial cell-mediated protective or detrimental effects on other cardiac cells. This review provides a more comprehensive understanding of the overall role of endothelial cells in cardiac hypertrophy and guides the therapeutic approaches and drug development of cardiac hypertrophy.
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Affiliation(s)
- Xing Yang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430000, China
| | - Kun Cheng
- Hepatic Surgery Centre, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430000, China
| | - Lu-Yun Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430000, China.
| | - Jian-Gang Jiang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430000, China.
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7
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Zhang Q, Sjögren B. Palmitoylation of RGS20 affects Gα o-mediated signaling independent of its GAP activity. Cell Signal 2023; 107:110682. [PMID: 37075876 DOI: 10.1016/j.cellsig.2023.110682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 04/07/2023] [Accepted: 04/15/2023] [Indexed: 04/21/2023]
Abstract
Regulator of protein signaling (RGS20) is a member of the RGS protein superfamily, which serve as key negative regulators of G protein-mediated signal transduction. Through their GTPase accelerating protein (GAP) activity, RGS proteins deactivate α-subunits of heterotrimeric G proteins. In addition, the majority of RGS proteins also have the ability to act through other, non-GAP related, functions. RGS20 is one of three members of the RZ subfamily, which all show selective GAP activity towards Gαz, however emerging data suggest that RGS20 can also regulate Gi/o-mediated signaling. While increased RGS20 expression is associated with the progression of multiple cancers, a large gap still exists relating to the mechanisms of RGS20 regulation and function. RGS20 contains a poly-cysteine string motif and a conserved cysteine in RGS domain, which are assumed to be palmitoylated. Palmitoylation, an important post-translational modification, plays an important role in cells by changing cellular functions of proteins. Consequently, the aim of this study was to confirm that RGS20 is palmitoylated and determine how palmitoylation affects its inhibition of Gαo-mediated signaling. We found a significant positive correlation between RGS20 palmitoylation and its association with active Gαo. We also showed that a conserved cysteine residue in the RGS domain is a critical site for its palmitoylation, with large impact on its association with Gαo. Palmitoylation on this site did not affect its GAP activity, however, it increased the inhibition of Gαo-mediated cAMP signaling. Altogether these data suggest that palmitoylation is a regulatory mechanism controlling RGS20 function, and that RGS20 can inhibit Gαo signaling through both GAP activity and non-GAP mechanisms.
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Affiliation(s)
- Qian Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America.
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8
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Smith E, Keeley TP. Monitoring ADO dependent proteolysis in cells using fluorescent reporter proteins. Methods Enzymol 2023. [PMID: 37532403 DOI: 10.1016/bs.mie.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
2-Aminoethanethiol dioxygenase (ADO) is the mammalian orthologue of the plant cysteine oxidases and together these enzymes are responsible for catalysing dioxygenation of N-terminal cysteine residues of certain proteins. This modification creates an N-degron motif that permits arginylation and subsequent proteasomal degradation of such proteins via the Arg-branch of the N-degron pathway. In humans 4 proteins have been identified as substrates of ADO; regulators of G-protein signalling (RGS) 4, 5 and 16, and interleukin-32 (IL-32). Nt-cysteine dioxygenation of these proteins occurs rapidly under normoxic conditions, but ADO activity is very sensitive to O2 availability and as such the stability of substrate proteins is inversely proportional to cellular O2 levels. Much is still to understand about the biochemistry and physiology of this pathway in vitro and in vivo, and Cys N-degron targeted fluorescent proteins can provide a simple and effective tool to study this at both subcellular and high-throughput scales. This chapter describes the design, production and implementation of a fluorescent fusion protein proteolytically regulated by ADO and the N-degron pathway.
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Kashina AS. Assaying ATE1 Activity in Yeast by β-Gal Degradation. Methods Mol Biol 2023; 2620:63-70. [PMID: 37010749 DOI: 10.1007/978-1-0716-2942-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
In the 1980s, it was found that addition of N-terminal Arg to proteins induces their ubiquitination and degradation by the N-end rule pathway. While this mechanism applies only to the proteins which also have other features of the N-degron (including a closely adjacent Lys that is accessible for ubiquitination), several test substrates have been found to follow this mechanism very efficiently after ATE1-dependent arginylation. Such property enabled researchers to test ATE1 activity in cells indirectly by assaying for the degradation of such arginylation-dependent substrates. The most commonly used substrate for this assay is E. coli beta-galactosidase (beta-Gal) because its level can be easily measured using standardized colorimetric assays. Here, we describe this method, which has served as a quick and easy way to characterize ATE1 activity during identification of arginyltransferases in different species.
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Affiliation(s)
- Anna S Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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10
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Kashina AS. Protein Arginylation: Milestones of Discovery. Methods Mol Biol 2023; 2620:1-13. [PMID: 37010742 DOI: 10.1007/978-1-0716-2942-0_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Posttranslational modifications have emerged in recent years as the major biological regulators responsible for the orders of magnitude increase in complexity during gene expression and regulation. These "molecular switches" affect nearly every protein in vivo by modulating their structure, activity, molecular interactions, and homeostasis ultimately regulating their functions. While over 350 posttranslational modifications have been described, only a handful of them have been characterized. Until recently, protein arginylation has belonged to the list of obscure, poorly understood posttranslational modifications, before the recent explosion of studies has put arginylation on the map of intracellular metabolic pathways and biological functions. This chapter contains an overview of all the major milestones in the protein arginylation field, from its original discovery in 1963 to this day.
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Affiliation(s)
- Anna S Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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11
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Moorthy BT, Jiang C, Patel DM, Ban Y, O'Shea CR, Kumar A, Yuan T, Birnbaum MD, Gomes AV, Chen X, Fontanesi F, Lampidis TJ, Barrientos A, Zhang F. The evolutionarily conserved arginyltransferase 1 mediates a pVHL-independent oxygen-sensing pathway in mammalian cells. Dev Cell 2022; 57:654-669.e9. [PMID: 35247316 PMCID: PMC8957288 DOI: 10.1016/j.devcel.2022.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 12/01/2021] [Accepted: 02/07/2022] [Indexed: 12/20/2022]
Abstract
The response to oxygen availability is a fundamental process concerning metabolism and survival/death in all mitochondria-containing eukaryotes. However, the known oxygen-sensing mechanism in mammalian cells depends on pVHL, which is only found among metazoans but not in other species. Here, we present an alternative oxygen-sensing pathway regulated by ATE1, an enzyme ubiquitously conserved in eukaryotes that influences protein degradation by posttranslational arginylation. We report that ATE1 centrally controls the hypoxic response and glycolysis in mammalian cells by preferentially arginylating HIF1α that is hydroxylated by PHD in the presence of oxygen. Furthermore, the degradation of arginylated HIF1α is independent of pVHL E3 ubiquitin ligase but dependent on the UBR family proteins. Bioinformatic analysis of human tumor data reveals that the ATE1/UBR and pVHL pathways jointly regulate oxygen sensing in a transcription-independent manner with different tissue specificities. Phylogenetic analysis suggests that eukaryotic ATE1 likely evolved during mitochondrial domestication, much earlier than pVHL.
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Affiliation(s)
- Balaji T Moorthy
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Chunhua Jiang
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Devang M Patel
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Yuguang Ban
- Department of Public Health Sciences, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Corin R O'Shea
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Akhilesh Kumar
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Tan Yuan
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Michael D Birnbaum
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Xi Chen
- Department of Public Health Sciences, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Flavia Fontanesi
- Department of Biochemistry & Molecular Biology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Theodore J Lampidis
- Department of Cell Biology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry & Molecular Biology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Fangliang Zhang
- Department of Molecular & Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA.
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12
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Fina ME, Wang J, Vedula P, Tang HY, Kashina A, Dong DW. Arginylation Regulates G-protein Signaling in the Retina. Front Cell Dev Biol 2022; 9:807345. [PMID: 35127722 PMCID: PMC8815403 DOI: 10.3389/fcell.2021.807345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/17/2021] [Indexed: 12/03/2022] Open
Abstract
Arginylation is a post-translational modification mediated by the arginyltransferase (Ate1). We recently showed that conditional deletion of Ate1 in the nervous system leads to increased light-evoked response sensitivities of ON-bipolar cells in the retina, indicating that arginylation regulates the G-protein signaling complexes of those neurons and/or photoreceptors. However, none of the key players in the signaling pathway were previously shown to be arginylated. Here we show that Gαt1, Gβ1, RGS6, and RGS7 are arginylated in the retina and RGS6 and RGS7 protein levels are elevated in Ate1 knockout, suggesting that arginylation plays a direct role in regulating their protein level and the G-protein-mediated responses in the retina.
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Affiliation(s)
- Marie E. Fina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Junling Wang
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Pavan Vedula
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA, United States
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
- *Correspondence: Anna Kashina, ; Dawei W. Dong,
| | - Dawei W. Dong
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
- Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- *Correspondence: Anna Kashina, ; Dawei W. Dong,
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13
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Kishimoto N, Okano R, Akita A, Miura S, Irie A, Takamune N, Misumi S. Arginyl-tRNA-protein transferase 1 contributes to governing optimal stability of the human immunodeficiency virus type 1 core. Retrovirology 2021; 18:30. [PMID: 34565409 PMCID: PMC8474785 DOI: 10.1186/s12977-021-00574-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 09/12/2021] [Indexed: 11/15/2022] Open
Abstract
Background The genome of human immunodeficiency virus type 1 (HIV-1) is encapsulated in a core consisting of viral capsid proteins (CA). After viral entry, the HIV-1 core dissociates and releases the viral genome into the target cell, this process is called uncoating. Uncoating of HIV-1 core is one of the critical events in viral replication and several studies show that host proteins positively or negatively regulate this process by interacting directly with the HIV-1 CA. Results Here, we show that arginyl-tRNA-protein transferase 1 (ATE1) plays an important role in the uncoating process by governing the optimal core stability. Yeast two-hybrid screening of a human cDNA library identified ATE1 as an HIV-1-CA-interacting protein and direct interaction of ATE1 with Pr55gag and p160gag − pol via HIV-1 CA was observed by cell-based pull-down assay. ATE1 knockdown in HIV-1 producer cells resulted in the production of less infectious viruses, which have normal amounts of the early products of the reverse transcription reaction but reduced amounts of the late products of the reverse transcription. Interestingly, ATE1 overexpression in HIV-1 producer cells also resulted in the production of poor infectious viruses. Cell-based fate-of-capsid assay, a commonly used method for evaluating uncoating by measuring core stability, showed that the amounts of pelletable cores in cells infected with the virus produced from ATE1-knockdown cells increased compared with those detected in the cells infected with the control virus. In contrast, the amounts of pelletable cores in cells infected with the virus produced from ATE1-overexpressing cells decreased compared with those detected in the cells infected with the control virus. Conclusions These results indicate that ATE1 expression levels in HIV-1 producer cells contribute to the adequate formation of a stable HIV-1 core. These findings provide insights into a novel mechanism of HIV-1 uncoating and revealed ATE1 as a new host factor regulating HIV-1 replication. Graphic abstract ![]()
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Affiliation(s)
- Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Ryosuke Okano
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Ayano Akita
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Satoshi Miura
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Ayaka Irie
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Nobutoki Takamune
- Kumamoto Innovative Development Organization, Kumamoto University, Kumamoto, 860- 8555, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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14
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Xu C, Li YM, Sun B, Zhong FJ, Yang LY. ATE1 Inhibits Liver Cancer Progression through RGS5-Mediated Suppression of Wnt/β-Catenin Signaling. Mol Cancer Res 2021; 19:1441-1453. [PMID: 34158395 PMCID: PMC9398136 DOI: 10.1158/1541-7786.mcr-21-0027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 05/04/2021] [Accepted: 06/15/2021] [Indexed: 01/07/2023]
Abstract
Arginyltransferase (ATE1) plays critical roles in many biological functions including cardiovascular development, angiogenesis, adipogenesis, muscle contraction, and metastasis of cancer. However, the role of ATE1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we find that ATE1 plays an essential role in growth and malignancy of liver cancer. ATE1 expression is significantly reduced in human HCC samples compared with normal liver tissue. In addition, low ATE1 expression is correlated with aggressive clinicopathologic features and is an independent poor prognostic factor for overall survival and disease-free survival of patients with HCC. Lentivirus-mediated ATE1 knockdown significantly promoted liver cancer growth, migration, and disease progression in vitro and in vivo. Opposing results were observed when ATE1 was upregulated. Mechanistically, ATE1 accelerated the degradation of β-catenin and inhibited Wnt signaling by regulating turnover of Regulator of G Protein Signaling 5 (RGS5). Loss- and gain-of-function assays confirmed that RGS5 was a key effector of ATE1-mediated regulation of Wnt signaling. Further studies indicated that RGS5 might be involved in regulating the activity of GSK3-β, a crucial component of the cytoplasmic destruction complex. Treatment with a GSK inhibitor (CHIR99021) cooperated with ablation of ATE1 or RGS5 overexpression to promote Wnt/β-catenin signaling, but overexpression of ATE1 or RGS5 knockdown did not reverse the effect of GSK inhibitor. IMPLICATIONS: ATE1 inhibits liver cancer progression by suppressing Wnt/β-catenin signaling and can serve as a potentially valuable prognostic biomarker for HCC.
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Affiliation(s)
- Cong Xu
- Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yi-Ming Li
- Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bo Sun
- Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fang-Jing Zhong
- Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lian-Yue Yang
- Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Corresponding Author: Lian-Yue Yang, Department of Surgery, Xiangya Hospital, Central South University, Xiangya Road 87, Changsha, Hunan 410008, China. Phone: 731-8432-7365; Fax: 731-8432-7618; E-mail:
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15
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Signaling Pathways Regulated by UBR Box-Containing E3 Ligases. Int J Mol Sci 2021; 22:ijms22158323. [PMID: 34361089 PMCID: PMC8346999 DOI: 10.3390/ijms22158323] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/31/2022] Open
Abstract
UBR box E3 ligases, also called N-recognins, are integral components of the N-degron pathway. Representative N-recognins include UBR1, UBR2, UBR4, and UBR5, and they bind destabilizing N-terminal residues, termed N-degrons. Understanding the molecular bases of their substrate recognition and the biological impact of the clearance of their substrates on cellular signaling pathways can provide valuable insights into the regulation of these pathways. This review provides an overview of the current knowledge of the binding mechanism of UBR box N-recognin/N-degron interactions and their roles in signaling pathways linked to G-protein-coupled receptors, apoptosis, mitochondrial quality control, inflammation, and DNA damage. The targeting of these UBR box N-recognins can provide potential therapies to treat diseases such as cancer and neurodegenerative diseases.
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16
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Jeon JH, Oh TR, Park S, Huh S, Kim JH, Mai BK, Lee JH, Kim SH, Lee MJ. The Antipsychotic Drug Clozapine Suppresses the RGS4 Polyubiquitylation and Proteasomal Degradation Mediated by the Arg/N-Degron Pathway. Neurotherapeutics 2021; 18:1768-1782. [PMID: 33884581 PMCID: PMC8608952 DOI: 10.1007/s13311-021-01039-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2021] [Indexed: 02/04/2023] Open
Abstract
Although diverse antipsychotic drugs have been developed for the treatment of schizophrenia, most of their mechanisms of action remain elusive. Regulator of G-protein signaling 4 (RGS4) has been reported to be linked, both genetically and functionally, with schizophrenia and is a physiological substrate of the arginylation branch of the N-degron pathway (Arg/N-degron pathway). Here, we show that the atypical antipsychotic drug clozapine significantly inhibits proteasomal degradation of RGS4 proteins without affecting their transcriptional expression. In addition, the levels of Arg- and Phe-GFP (artificial substrates of the Arg/N-degron pathway) were significantly elevated by clozapine treatment. In silico computational model suggested that clozapine may interact with active sites of N-recognin E3 ubiquitin ligases. Accordingly, treatment with clozapine resulted in reduced polyubiquitylation of RGS4 and Arg-GFP in the test tube and in cultured cells. Clozapine attenuated the activation of downstream effectors of G protein-coupled receptor signaling, such as MEK1 and ERK1, in HEK293 and SH-SY5Y cells. Furthermore, intraperitoneal injection of clozapine into rats significantly stabilized the endogenous RGS4 protein in the prefrontal cortex. Overall, these results reveal an additional therapeutic mechanism of action of clozapine: this drug posttranslationally inhibits the degradation of Arg/N-degron substrates, including RGS4. These findings imply that modulation of protein post-translational modifications, in particular the Arg/N-degron pathway, may be a novel molecular therapeutic strategy against schizophrenia.
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Affiliation(s)
- Jun Hyoung Jeon
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Tae Rim Oh
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Seoyoung Park
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Sunghoo Huh
- Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea
| | - Ji Hyeon Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Se Hyun Kim
- Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea.
- Department of Psychiatry, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, 03080, Korea.
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea.
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea.
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17
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Fina ME, Wang J, Nikonov SS, Sterling S, Vardi N, Kashina A, Dong DW. Arginyltransferase (Ate1) regulates the RGS7 protein level and the sensitivity of light-evoked ON-bipolar responses. Sci Rep 2021; 11:9376. [PMID: 33931669 PMCID: PMC8087773 DOI: 10.1038/s41598-021-88628-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/14/2021] [Indexed: 12/16/2022] Open
Abstract
Regulator of G-protein signaling 7 (RGS7) is predominately present in the nervous system and is essential for neuronal signaling involving G-proteins. Prior studies in cultured cells showed that RGS7 is regulated via proteasomal degradation, however no protein is known to facilitate proteasomal degradation of RGS7 and it has not been shown whether this regulation affects G-protein signaling in neurons. Here we used a knockout mouse model with conditional deletion of arginyltransferase (Ate1) in the nervous system and found that in retinal ON bipolar cells, where RGS7 modulates a G-protein to signal light increments, deletion of Ate1 raised the level of RGS7. Electroretinographs revealed that lack of Ate1 leads to increased light-evoked response sensitivities of ON-bipolar cells, as well as their downstream neurons. In cultured mouse embryonic fibroblasts (MEF), RGS7 was rapidly degraded via proteasome pathway and this degradation was abolished in Ate1 knockout MEF. Our results indicate that Ate1 regulates RGS7 protein level by facilitating proteasomal degradation of RGS7 and thus affects G-protein signaling in neurons.
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Affiliation(s)
- Marie E Fina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Junling Wang
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sergei S Nikonov
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Stephanie Sterling
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Noga Vardi
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Dawei W Dong
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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18
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McNabb HJ, Gonzalez S, Muli CS, Sjögren B. N-Terminal Targeting of Regulator of G Protein Signaling Protein 2 for F-Box Only Protein 44-Mediated Proteasomal Degradation. Mol Pharmacol 2020; 98:677-685. [PMID: 33008920 DOI: 10.1124/molpharm.120.000061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/17/2020] [Indexed: 12/28/2022] Open
Abstract
Regulator of G protein signaling (RGS) proteins are negative modulators of G protein signaling that have emerged as promising drug targets to improve specificity and reduce side effects of G protein-coupled receptor-related therapies. Several small molecule RGS protein inhibitors have been identified; however, enhancing RGS protein function is often more clinically desirable but presents a challenge. Low protein levels of RGS2 are associated with various pathologies, including hypertension and heart failure. For this reason, RGS2 is a prominent example wherein enhancing its function would be beneficial. RGS2 is rapidly ubiquitinated and proteasomally degraded, providing a point of intervention for small molecule RGS2-stabilizing compounds. We previously identified a novel cullin-RING E3 ligase utilizing F-box only protein 44 (FBXO44) as the substrate recognition component. Here, we demonstrate that RGS2 associates with FBXO44 through a stretch of residues in its N terminus. RGS2 contains four methionine residues close to the N terminus that can act as alternative translation initiation sites. The shorter translation initiation variants display reduced ubiquitination and proteasomal degradation as a result of lost association with FBXO44. In addition, we show that phosphorylation of Ser3 may be an additional mechanism to protect RGS2 from FBXO44-mediated proteasomal degradation. These findings contribute to elucidating mechanisms regulating steady state levels of RGS2 protein and will inform future studies to develop small molecule RGS2 stabilizers. These would serve as novel leads in pathologies associated with low RGS2 protein levels, such as hypertension, heart failure, and anxiety. SIGNIFICANCE STATEMENT: E3 ligases provide a novel point of intervention for therapeutic development, but progress is hindered by the lack of available information about specific E3-substrate pairs. Here, we provide molecular detail on the recognition of regulator of G protein signaling protein 2 (RGS2) by its E3 ligase, increasing the potential for rational design of small molecule RGS2 protein stabilizers. These would be clinically useful in pathologies associated with low RGS2 protein levels, such as hypertension, heart failure, and anxiety.
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Affiliation(s)
- Harrison J McNabb
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Stephanie Gonzalez
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Christine S Muli
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
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19
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Heat stress induced arginylation of HuR promotes alternative polyadenylation of Hsp70.3 by regulating HuR stability and RNA binding. Cell Death Differ 2020; 28:730-747. [PMID: 32929216 DOI: 10.1038/s41418-020-00619-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 11/08/2022] Open
Abstract
Arginylation was previously found to promote stabilization of heat shock protein 70.3 (Hsp70.3) mRNA and cell survival in mouse embryonic fibroblasts (MEFs) on exposure to heat stress (HS). In search of a factor responsible for these phenomena, the current study identified human antigen R (HuR) as a direct target of arginylation. HS induced arginylation of HuR affected its stability and RNA binding activity. Arginylated HuR failed to bind Hsp70.3 3' UTR, allowing the recruitment of cleavage stimulating factor 64 (CstF64) in the proximal poly-A-site (PAS), generating transcripts with short 3'UTR. However, HuR from Ate1 knock out (KO) MEFs bound to proximal PAS region with higher affinity, thus excluded CstF64 recruitment. This inhibited the alternative polyadenylation (APA) of Hsp70.3 mRNA and generated the unstable transcripts with long 3'UTR. The inhibition of RNA binding activity of HuR was traced to arginylation-coupled phosphorylation of HuR, by check point kinase 2 (Chk2). Arginylation of HuR occurred at the residue D15 and the arginylation was needed for the phosphorylation. Accumulation of HuR also decreased cell viability upon HS. In conclusion, arginylation dependent modifications of HuR maintained its cellular homeostasis, and promoted APA of Hsp70.3 pre-mRNA, during early HS response.
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20
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Ehses J, Fernández-Moya SM, Schröger L, Kiebler MA. Synergistic regulation of Rgs4 mRNA by HuR and miR-26/RISC in neurons. RNA Biol 2020; 18:988-998. [PMID: 32779957 PMCID: PMC8216180 DOI: 10.1080/15476286.2020.1795409] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The negative regulator of G-protein signalling 4 (Rgs4) is linked to several neurologic diseases, e.g. schizophrenia, addiction, seizure and pain perception. Consequently, Rgs4 expression is tightly regulated, resulting in high mRNA and protein turnover. The post-transcriptional control of gene expression is mediated via RNA-binding proteins (RBPs) that interact with mRNAs in a combinatorial fashion. Here, we show that in neurons the RBP HuR reduces endogenous Rgs4 expression by destabilizing Rgs4 mRNA. Interestingly, in smooth muscle cells, Rgs4 is stabilized by HuR, indicating tissue-dependent differences in HuR function. Using in vitro RNA-based pulldown experiments, we identify the functional AU-rich element (ARE) within the Rgs4 3ʹ-UTR that is recognized and bound by HuR. Bioinformatic analysis uncovered that this ARE lies within a highly conserved area next to a miR-26 binding site. We find that the neuronal-enriched miR-26 negatively influences Rgs4 expression in neurons. Further, HuR and miR-26 act synergistically in fluorescent reporter assays. Together, our data suggest a regulatory mechanism, in which an RBP selectively destabilizes a target mRNA in cooperation with a miRNA and the RISC machinery.
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Affiliation(s)
- Janina Ehses
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Sandra M Fernández-Moya
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Luise Schröger
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Michael A Kiebler
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
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21
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Elfiky AA, Ibrahim IM. Zika virus envelope - heat shock protein A5 (GRP78) binding site prediction. J Biomol Struct Dyn 2020; 39:5248-5260. [PMID: 32579073 DOI: 10.1080/07391102.2020.1784794] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Recent studies reported the association of the Zika virus (ZIKV) with a stress response receptor on the host cell membrane that facilitates viral entry. This host receptor was the heat shock protein A5 (HSPA5), also termed glucose-regulating protein 78 (GRP78). In this study, structural bioinformatics and molecular dynamics simulations were utilized to suggest the binding site of ZIKV envelope protein during the interaction with cell-surface GRP78. The Pep42 cyclic peptide was used as a profiler, as it was reported earlier, to target GRP78 on the cancer cell membrane selectively. Sequence and structural alignments show that part of the ZIKV envelope protein (C308-C339 region), in addition to its cyclic nature, has somehow sequence and structural similarities to the cyclic Pep42. Three amino acids in the ZIKV envelope were identical to those in the Pep42 peptide. Cyclic peptides dynamics are studied, and its binding to GRP78 is predicted. Protein-protein docking is further performed to explore the binding characteristics of the ZIKV envelope to GRP78. Results revealed that the binding was favorable between ZIKV envelope protein and GRP78. The docking pose revealed the involvement of the substrate-binding domain ß of GRP78 and the domain III of the ZIKV envelope protein in viral recognition for the host-cell.
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Affiliation(s)
- Abdo A Elfiky
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Egypt
| | - Ibrahim M Ibrahim
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Egypt
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22
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Rassier DE, Kashina A. Protein arginylation of cytoskeletal proteins in the muscle: modifications modifying function. Am J Physiol Cell Physiol 2019; 316:C668-C677. [PMID: 30789755 PMCID: PMC6580163 DOI: 10.1152/ajpcell.00500.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/30/2022]
Abstract
The cytoskeleton drives many essential processes in normal physiology, and its impairments underlie many diseases, including skeletal myopathies, cancer, and heart failure, that broadly affect developed countries worldwide. Cytoskeleton regulation is a field of investigation of rapidly emerging global importance and a new venue for the development of potential therapies. This review overviews our present understanding of the posttranslational regulation of the muscle cytoskeleton through arginylation, a tRNA-dependent addition of arginine to proteins mediated by arginyltransferase 1. We focus largely on arginylation-dependent regulation of striated muscles, shown to play critical roles in facilitating muscle integrity, contractility, regulation, and strength.
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Affiliation(s)
- Dilson E Rassier
- Department of Kinesiology and Physical Education, McGill University , Montreal, Quebec , Canada
| | - Anna Kashina
- Department of Biomedical Sciences, University of Pennsylvania , Philadelphia, Pennsylvania
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23
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Dissmeyer N. Conditional Protein Function via N-Degron Pathway-Mediated Proteostasis in Stress Physiology. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:83-117. [PMID: 30892918 DOI: 10.1146/annurev-arplant-050718-095937] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The N-degron pathway, formerly the N-end rule pathway, regulates functions of regulatory proteins. It impacts protein half-life and therefore directs the actual presence of target proteins in the cell. The current concept holds that the N-degron pathway depends on the identity of the amino (N)-terminal amino acid and many other factors, such as the follow-up sequence at the N terminus, conformation, flexibility, and protein localization. It is evolutionarily conserved throughout the kingdoms. One possible entry point for substrates of the N-degron pathway is oxidation of N-terminal Cys residues. Oxidation of N-terminal Cys is decisive for further enzymatic modification of various neo-N termini by arginylation that generates potentially neofunctionalized or instable proteoforms. Here, I focus on the posttranslational modifications that are encompassed by protein degradation via the Cys/Arg branch of the N-degron pathway-part of the PROTEOLYSIS 6 (PRT6)/N-degron pathway-as well as the underlying physiological principles of this branch and its biological significance in stress response.
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Affiliation(s)
- Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB) and ScienceCampus Halle-Plant-Based Bioeconomy, D-06120 Halle (Saale), Germany; ; Twitter: @NDissmeyer
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24
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Singh A, Borah AK, Deka K, Gogoi AP, Verma K, Barah P, Saha S. Arginylation regulates adipogenesis by regulating expression of PPARγ at transcript and protein level. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:596-607. [DOI: 10.1016/j.bbalip.2018.12.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 11/28/2022]
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25
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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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26
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Wang Z, Xia X, Yang X, Zhang X, Liu Y, Wu D, Fang Y, Liu Y, Xu J, Qiu Y, Zhou X. A picorna-like virus suppresses the N-end rule pathway to inhibit apoptosis. eLife 2017; 6:30590. [PMID: 29231806 PMCID: PMC5739542 DOI: 10.7554/elife.30590] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/11/2017] [Indexed: 12/21/2022] Open
Abstract
The N-end rule pathway is an evolutionarily conserved proteolytic system that degrades proteins containing N-terminal degradation signals called N-degrons, and has emerged as a key regulator of various processes. Viruses manipulate diverse host pathways to facilitate viral replication and evade antiviral defenses. However, it remains unclear if viral infection has any impact on the N-end rule pathway. Here, using a picorna-like virus as a model, we found that viral infection promoted the accumulation of caspase-cleaved Drosophila inhibitor of apoptosis 1 (DIAP1) by inducing the degradation of N-terminal amidohydrolase 1 (NTAN1), a key N-end rule component that identifies N-degron to initiate the process. The virus-induced NTAN1 degradation is independent of polyubiquitylation but dependent on proteasome. Furthermore, the virus-induced N-end rule pathway suppression inhibits apoptosis and benefits viral replication. Thus, our findings demonstrate that a virus can suppress the N-end rule pathway, and uncover a new mechanism for virus to evade apoptosis.
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Affiliation(s)
- Zhaowei Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoling Xia
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology & School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xueli Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xueyi Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yongxiang Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Di Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yuan Fang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yujie Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jiuyue Xu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yang Qiu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Xi Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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27
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Alqinyah M, Hooks SB. Regulating the regulators: Epigenetic, transcriptional, and post-translational regulation of RGS proteins. Cell Signal 2017; 42:77-87. [PMID: 29042285 DOI: 10.1016/j.cellsig.2017.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022]
Abstract
Regulators of G protein signaling (RGS) are a family of proteins classically known to accelerate the intrinsic GTPase activity of G proteins, which results in accelerated inactivation of heterotrimeric G proteins and inhibition of G protein coupled receptor signaling. RGS proteins play major roles in essential cellular processes, and dysregulation of RGS protein expression is implicated in multiple diseases, including cancer, cardiovascular and neurodegenerative diseases. The expression of RGS proteins is highly dynamic and is regulated by epigenetic, transcriptional and post-translational mechanisms. This review summarizes studies that report dysregulation of RGS protein expression in disease states, and presents examples of drugs that regulate RGS protein expression. Additionally, this review discusses, in detail, the transcriptional and post-transcriptional mechanisms regulating RGS protein expression, and further assesses the therapeutic potential of targeting these mechanisms. Understanding the molecular mechanisms controlling the expression of RGS proteins is essential for the development of therapeutics that indirectly modulate G protein signaling by regulating expression of RGS proteins.
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Affiliation(s)
- Mohammed Alqinyah
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA.
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28
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Park HJ, Kim SH, Moon DO. Growth inhibition of human breast carcinoma cells by overexpression of regulator of G-protein signaling 4. Oncol Lett 2017; 13:4357-4363. [PMID: 28588709 DOI: 10.3892/ol.2017.6009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/15/2016] [Indexed: 01/05/2023] Open
Abstract
Breast cancer remains the second largest cause of mortality in women with cancer and does not respond well to conventional therapies. Regulator of G-protein signaling 4 (RGS4) is a GTPase-activating protein of the heterotrimeric Gq and Gi proteins. Altered levels of RGS4 are reportedly linked with several human diseases, including cancer. The present study investigated whether overexpression of RGS4 inhibited the growth of human breast cancer cells. Protein expression was investigated by western blot analysis. Cell viability and apoptosis were analyzed by MTT assay and flow cytometric analysis, respectively. Cell cycle analysis was performed using propidium iodide staining in order to examine the anti-proliferative function of increased RGS4 levels. Next, changes in the expression levels of G2/M cell cycle-related proteins were examined. Overexpression of RGS4 led to the upregulation of phosphorylayed (p)-Ser216 cell division cycle (Cdc)25C and p-Tyr15 Cdc2. Importantly, MG132-induced proteasome blockade prevented degradation of RGS4. Suppression of proliferation was associated with G2/M-phase cell cycle arrest. Furthermore, enhanced endogenous RGS4 protein levels significantly inhibited breast cancer cell growth, which was reversed by a pharmacological inhibitor of RGS4. Taken together, these results suggest that overexpression of RGS4 in human breast cancer cells by molecular means may offer a potential therapeutic approach.
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Affiliation(s)
- Hyun-Jung Park
- Department of Biology Education, Daegu University, Gyeongsan, Gyeongsangbuk-do 38453, Republic of Korea
| | - Seung-Hyun Kim
- Department of Biology Education, Daegu University, Gyeongsan, Gyeongsangbuk-do 38453, Republic of Korea
| | - Dong-Oh Moon
- Department of Biology Education, Daegu University, Gyeongsan, Gyeongsangbuk-do 38453, Republic of Korea
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29
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Plant cysteine oxidases are dioxygenases that directly enable arginyl transferase-catalysed arginylation of N-end rule targets. Nat Commun 2017; 8:14690. [PMID: 28332493 PMCID: PMC5376641 DOI: 10.1038/ncomms14690] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/20/2017] [Indexed: 02/06/2023] Open
Abstract
Crop yield loss due to flooding is a threat to food security. Submergence-induced hypoxia in plants results in stabilization of group VII ETHYLENE RESPONSE FACTORs (ERF-VIIs), which aid survival under these adverse conditions. ERF-VII stability is controlled by the N-end rule pathway, which proposes that ERF-VII N-terminal cysteine oxidation in normoxia enables arginylation followed by proteasomal degradation. The PLANT CYSTEINE OXIDASEs (PCOs) have been identified as catalysts of this oxidation. ERF-VII stabilization in hypoxia presumably arises from reduced PCO activity. We directly demonstrate that PCO dioxygenase activity produces Cys-sulfinic acid at the N terminus of an ERF-VII peptide, which then undergoes efficient arginylation by an arginyl transferase (ATE1). This provides molecular evidence of N-terminal Cys-sulfinic acid formation and arginylation by N-end rule pathway components, and a substrate of ATE1 in plants. The PCOs and ATE1 may be viable intervention targets to stabilize N-end rule substrates, including ERF-VIIs, to enhance submergence tolerance in agriculture. The N-end rule pathway targets substrate proteins for proteasomal degradation. Here, White et al. show that Arabidopsis PLANT CYSTEINE OXIDASEs show dioxygenase activity producing Cys-sulfinic acid at the N-terminus of target proteins, which then act as direct substrates for arginyl transferase.
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30
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Sjögren B. The evolution of regulators of G protein signalling proteins as drug targets - 20 years in the making: IUPHAR Review 21. Br J Pharmacol 2017; 174:427-437. [PMID: 28098342 DOI: 10.1111/bph.13716] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/11/2016] [Accepted: 01/08/2017] [Indexed: 12/11/2022] Open
Abstract
Regulators of G protein signalling (RGS) proteins are celebrating the 20th anniversary of their discovery. The unveiling of this new family of negative regulators of G protein signalling in the mid-1990s solved a persistent conundrum in the G protein signalling field, in which the rate of deactivation of signalling cascades in vivo could not be replicated in exogenous systems. Since then, there has been tremendous advancement in the knowledge of RGS protein structure, function, regulation and their role as novel drug targets. RGS proteins play an important modulatory role through their GTPase-activating protein (GAP) activity at active, GTP-bound Gα subunits of heterotrimeric G proteins. They also possess many non-canonical functions not related to G protein signalling. Here, an update on the status of RGS proteins as drug targets is provided, highlighting advances that have led to the inclusion of RGS proteins in the IUPHAR/BPS Guide to PHARMACOLOGY database of drug targets.
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Affiliation(s)
- B Sjögren
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
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31
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Abstract
Determination of the general capacity of proteolytic activity of a certain cell or tissue type can be crucial for an assessment of various features of an organism's growth and development and also for the optimization of biotechnological applications. Here, we describe the use of chimeric protein stability reporters that can be detected by standard laboratory techniques such as histological staining, selection using selective media or fluorescence microscopy. Dependent on the expression of the reporters due to the promoters applied, cell- and tissue-specific questions can be addressed. Here, we concentrate on methods which can be used for large-scale screening for protein stability changes rather than for detailed protein stability studies.
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Affiliation(s)
- Pavel Reichman
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB) and Science Campus Halle - Plant-Based Bioeconomy, Halle (Saale), Germany
| | - Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB) and Science Campus Halle - Plant-Based Bioeconomy, Halle (Saale), Germany.
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32
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Deka K, Singh A, Chakraborty S, Mukhopadhyay R, Saha S. Protein arginylation regulates cellular stress response by stabilizing HSP70 and HSP40 transcripts. Cell Death Discov 2016; 2:16074. [PMID: 27752365 PMCID: PMC5045964 DOI: 10.1038/cddiscovery.2016.74] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/23/2016] [Indexed: 01/29/2023] Open
Abstract
ATE1-mediated post-translational addition of arginine to a protein has been shown to regulate activity, interaction, and stability of the protein substrates. Arginylation has been linked to many different stress conditions, namely ER stress, cytosolic misfolded protein stress, and nitrosative stress. However, clear understanding about the effect of arginylation in cellular stress responses is yet to emerge. In this study, we investigated the role of arginylation in heat-stress response. Our findings suggest that Ate1 knock out (KO) cells are more susceptible to heat stress compared with its wild-type counterparts due to the induction of apoptosis in KO cells. Gene expression analysis of inducible heat-shock proteins (HSP70.1, HSP70.3, and HSP40) showed induction of these genes in KO cells early in the heat shock, but were drastically diminished at the later period of heat shock. Further analysis revealed that loss of ATE1 drastically reduced the stability of all three HSP mRNAs. These phenotypes were greatly restored by overexpression of Ate1 in KO cells. Our findings show that arginylation plays a protective role during heat stress by regulating HSP gene expression and mRNA stability.
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Affiliation(s)
- Kamalakshi Deka
- Department of Molecular Biology and Biotechnology, Tezpur University , Napaam, Assam, India
| | - Archana Singh
- Department of Molecular Biology and Biotechnology, Tezpur University , Napaam, Assam, India
| | - Surajit Chakraborty
- Department of Molecular Biology and Biotechnology, Tezpur University , Napaam, Assam, India
| | - Rupak Mukhopadhyay
- Department of Molecular Biology and Biotechnology, Tezpur University , Napaam, Assam, India
| | - Sougata Saha
- Department of Molecular Biology and Biotechnology, Tezpur University , Napaam, Assam, India
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33
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Wadas B, Piatkov KI, Brower CS, Varshavsky A. Analyzing N-terminal Arginylation through the Use of Peptide Arrays and Degradation Assays. J Biol Chem 2016; 291:20976-20992. [PMID: 27510035 DOI: 10.1074/jbc.m116.747956] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Indexed: 01/29/2023] Open
Abstract
Nα-terminal arginylation (Nt-arginylation) of proteins is mediated by the Ate1 arginyltransferase (R-transferase), a component of the Arg/N-end rule pathway. This proteolytic system recognizes proteins containing N-terminal degradation signals called N-degrons, polyubiquitylates these proteins, and thereby causes their degradation by the proteasome. The definitively identified ("canonical") residues that are Nt-arginylated by R-transferase are N-terminal Asp, Glu, and (oxidized) Cys. Over the last decade, several publications have suggested (i) that Ate1 can also arginylate non-canonical N-terminal residues; (ii) that Ate1 is capable of arginylating not only α-amino groups of N-terminal residues but also γ-carboxyl groups of internal (non-N-terminal) Asp and Glu; and (iii) that some isoforms of Ate1 are specific for substrates bearing N-terminal Cys residues. In the present study, we employed arrays of immobilized 11-residue peptides and pulse-chase assays to examine the substrate specificity of mouse R-transferase. We show that amino acid sequences immediately downstream of a substrate's canonical (Nt-arginylatable) N-terminal residue, particularly a residue at position 2, can affect the rate of Nt-arginylation by R-transferase and thereby the rate of degradation of a substrate protein. We also show that the four major isoforms of mouse R-transferase have similar Nt-arginylation specificities in vitro, contrary to the claim about the specificity of some Ate1 isoforms for N-terminal Cys. In addition, we found no evidence for a significant activity of the Ate1 R-transferase toward previously invoked non-canonical N-terminal or internal amino acid residues. Together, our results raise technical concerns about earlier studies that invoked non-canonical arginylation specificities of Ate1.
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Affiliation(s)
- Brandon Wadas
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Konstantin I Piatkov
- the Center for Biotechnology and Biomedicine, Skolkovo Institute of Science and Technology, Moscow 143026, Russia, and
| | | | - Alexander Varshavsky
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125,
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34
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Galiano MR, Goitea VE, Hallak ME. Post-translational protein arginylation in the normal nervous system and in neurodegeneration. J Neurochem 2016; 138:506-17. [PMID: 27318192 DOI: 10.1111/jnc.13708] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/24/2016] [Accepted: 06/13/2016] [Indexed: 02/07/2023]
Abstract
Post-translational arginylation of proteins is an important regulator of many physiological pathways in cells. This modification was originally noted in protein degradation during neurodegenerative processes, with an apparently different physiological relevance between central and peripheral nervous system. Subsequent studies have identified a steadily increasing number of proteins and proteolysis-derived polypeptides as arginyltransferase (ATE1) substrates, including β-amyloid, α-synuclein, and TDP43 proteolytic fragments. Arginylation is involved in signaling processes of proteins and polypeptides that are further ubiquitinated and degraded by the proteasome. In addition, it is also implicated in autophagy/lysosomal degradation pathway. Recent studies using mutant mouse strains deficient in ATE1 indicate additional roles of this modification in neuronal physiology. As ATE1 is capable of modifying proteins either at the N-terminus or middle-chain acidic residues, determining which proteins function are modulated by arginylation represents a big challenge. Here, we review studies addressing various roles of ATE1 activity in nervous system function, and suggest future research directions that will clarify the role of post-translational protein arginylation in brain development and various neurological disorders. Arginyltransferase (ATE1), the enzyme responsible for post-translational arginylation, modulates the functions of a wide variety of proteins and polypeptides, and is also involved in the main degradation pathways of intracellular proteins. Regulatory roles of ATE1 have been well defined for certain organs. However, its roles in nervous system development and neurodegenerative processes remain largely unknown, and present exciting opportunities for future research, as discussed in this review.
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Affiliation(s)
- Mauricio R Galiano
- Centro de Investigaciones de Química Biológica de Córdoba, CIQUIBIC, Departamento de Química Biológica, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Victor E Goitea
- Centro de Investigaciones de Química Biológica de Córdoba, CIQUIBIC, Departamento de Química Biológica, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Marta E Hallak
- Centro de Investigaciones de Química Biológica de Córdoba, CIQUIBIC, Departamento de Química Biológica, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
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35
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Bilodeau J, Schwendt M. Post-cocaine changes in regulator of G-protein signaling (RGS) proteins in the dorsal striatum: Relevance for cocaine-seeking and protein kinase C-mediated phosphorylation. Synapse 2016; 70:432-40. [PMID: 27261631 DOI: 10.1002/syn.21917] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/19/2016] [Accepted: 06/01/2016] [Indexed: 12/27/2022]
Abstract
Persistent cocaine-induced neuroadaptations within the cortico-striatal circuitry might be related to elevated risk of relapse observed in human addicts even after months or years of drug-free abstinence. Identification of these neuroadaptations may lead development of novel, neurobiologically-based treatments of relapse. In the current study, 12 adult male Sprague-Dawley rats self-administered cocaine (or received yoked-saline) for two weeks followed by three weeks of home-cage abstinence. At this point, we analyzed expression of proteins involved in regulation of Gαi- and Gαq-protein signaling in the dorsal striatum (dSTR). Animals abstinent from chronic cocaine showed decreased expression of regulator of G-protein signaling 2 (RGS2) and RGS4, as well as upregulation of RGS9. These data, together with the increased ratio of Gαq-to-Gαi proteins indicated, "sensitized" Gαq signaling in the dSTR of abstinent cocaine animals. To evaluate activation of Gαq signaling during relapse, another group of abstinent cocaine animals (and yoked saline controls, 22 rats together) was reintroduced to the cocaine context and PKC-mediated phosphorylation in the dSTR was analyzed. Re-exposure to the cocaine context triggered cocaine seeking and increase in phosphorylation of cellular PKC substrates, including phospho-ERK and phospho-CREB. In conclusion, this study demonstrates persistent dysregulation of RGS proteins in the dSTR of abstinent cocaine animals that may produce an imbalance in local Gαq-to-Gαi signaling. This imbalance might be related to augmented PKC-mediated phosphorylation during relapse to cocaine-seeking. Future studies will address whether selective targeting of RGS proteins in the dSTR can be utilized to suppress PKC-mediated phosphorylation and relapse to cocaine-seeking.
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Affiliation(s)
- Jenna Bilodeau
- Psychology Department, University of Florida, Gainesville, Florida 32611-2250
| | - Marek Schwendt
- Psychology Department, University of Florida, Gainesville, Florida 32611-2250
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36
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Gerber KJ, Squires KE, Hepler JR. Roles for Regulator of G Protein Signaling Proteins in Synaptic Signaling and Plasticity. Mol Pharmacol 2015; 89:273-86. [PMID: 26655302 DOI: 10.1124/mol.115.102210] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/10/2015] [Indexed: 11/22/2022] Open
Abstract
The regulator of G protein signaling (RGS) family of proteins serves critical roles in G protein-coupled receptor (GPCR) and heterotrimeric G protein signal transduction. RGS proteins are best understood as negative regulators of GPCR/G protein signaling. They achieve this by acting as GTPase activating proteins (GAPs) for Gα subunits and accelerating the turnoff of G protein signaling. Many RGS proteins also bind additional signaling partners that either regulate their functions or enable them to regulate other important signaling events. At neuronal synapses, GPCRs, G proteins, and RGS proteins work in coordination to regulate key aspects of neurotransmitter release, synaptic transmission, and synaptic plasticity, which are necessary for central nervous system physiology and behavior. Accumulating evidence has revealed key roles for specific RGS proteins in multiple signaling pathways at neuronal synapses, regulating both pre- and postsynaptic signaling events and synaptic plasticity. Here, we review and highlight the current knowledge of specific RGS proteins (RGS2, RGS4, RGS7, RGS9-2, and RGS14) that have been clearly demonstrated to serve critical roles in modulating synaptic signaling and plasticity throughout the brain, and we consider their potential as future therapeutic targets.
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Affiliation(s)
- Kyle J Gerber
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - Katherine E Squires
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - John R Hepler
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
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37
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Lyu JH, Park DW, Huang B, Kang SH, Lee SJ, Lee C, Bae YS, Lee JG, Baek SH. RGS2 suppresses breast cancer cell growth via a MCPIP1-dependent pathway. J Cell Biochem 2015; 116:260-7. [PMID: 25187114 DOI: 10.1002/jcb.24964] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/29/2014] [Indexed: 01/22/2023]
Abstract
Regulator of G protein signaling 2 (RGS2) is a member of a family of proteins that functions as a GTPase-activating protein (GAP) for Gα subunits. RGS2 mRNA expression is lower in breast cancerous tissues than in normal tissues. In addition, expression of RGS2 is also lower in MCF7 (cancerous breast cells) than in MCF10A (normal breast cells). Here we investigated whether RGS2 inhibits growth of breast cancer cells. RGS2 overexpression in MCF7 cells inhibited epidermal growth factor- or serum-induced proliferation. In HEK293T cells expressing RGS2, cell growth was also significantly suppressed (In addition, exogenous expression of RGS2 in HEK293T cells resulted in the significant suppression of cell growth). These results suggest that RGS2 may have a tumor suppressor function. MG-132 treatment of MCF7 cells increased endogenous or exogenous RGS2 levels, suggesting a post-transcriptional regulatory mechanism that controls RGS2 protein levels. RGS2 protein was degraded polyubiquitinated the K71 residue, but stabilized by deubiquitinase monocyte chemotactic protein-induced protein 1 (MCPIP1), and not affected by dominant negative mutant (C157A) of MCPIP1. Gene expression profiling study showed that overexpression of RGS2 decreased levels of testis specific Y encoded like protein 5 (TSPYL5), which plays a causal role in breast oncogenesis. TSPYL5 protein expression was low in MCF10A and high in MCF7 cells, showing the opposite aspect to RGS2 expression. Additionally, RGS2 or MCPIP1 overexpression in MCF7 cells decreased TSPYL5 protein level, indicating that RGS2 stabilized by MCPIP1 have diminished TSPYL5 protein levels, thereby exerting an inhibitory effect of breast cancer cell growth.
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Affiliation(s)
- Ji Hyo Lyu
- Department of Biochemistry and Molecular Biology, Aging-Associated Vascular Disease Research Center, Daegu, 705-802, South Korea
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Opel A, Nobles M, Montaigne D, Finlay M, Anderson N, Breckenridge R, Tinker A. Absence of the Regulator of G-protein Signaling, RGS4, Predisposes to Atrial Fibrillation and Is Associated with Abnormal Calcium Handling. J Biol Chem 2015; 290:19233-44. [PMID: 26088132 PMCID: PMC4521044 DOI: 10.1074/jbc.m115.666719] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/15/2015] [Indexed: 01/11/2023] Open
Abstract
The description of potential molecular substrates for predisposition to atrial fibrillation (AF) is incomplete, and it is unknown what role regulators of G-protein signaling might play. We address whether the attenuation of RGS4 function may promote AF and the mechanism through which this occurs. For this purpose, we studied a mouse with global genetic deletion of RGS4 (RGS4(-/-)) and the normal littermate controls (RGS4(+/+)). In vivo electrophysiology using atrial burst pacing revealed that mice with global RGS4 deletion developed AF more frequently than control littermates. Isolated atrial cells from RGS4(-/-) mice show an increase in Ca(2+) spark frequency under basal conditions and after the addition of endothelin-1 and abnormal spontaneous Ca(2+) release events after field stimulation. Isolated left atria studied on a multielectrode array revealed modest changes in path length for re-entry but abnormal electrical events after a pacing train in RGS4(-/-) mice. RGS4 deletion results in a predisposition to atrial fibrillation from enhanced activity in the Gαq/11-IP3 pathway, resulting in abnormal Ca(2+) release and corresponding electrical events.
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Affiliation(s)
- Aaisha Opel
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Muriel Nobles
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - David Montaigne
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Malcolm Finlay
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Naomi Anderson
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Ross Breckenridge
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and
| | - Andrew Tinker
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
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Sjögren B, Swaney S, Neubig RR. FBXO44-Mediated Degradation of RGS2 Protein Uniquely Depends on a Cullin 4B/DDB1 Complex. PLoS One 2015; 10:e0123581. [PMID: 25970626 PMCID: PMC4430315 DOI: 10.1371/journal.pone.0123581] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/05/2015] [Indexed: 12/30/2022] Open
Abstract
The ubiquitin-proteasome system for protein degradation plays a major role in regulating cell function and many signaling proteins are tightly controlled by this mechanism. Among these, Regulator of G Protein Signaling 2 (RGS2) is a target for rapid proteasomal degradation, however, the specific enzymes involved are not known. Using a genomic siRNA screening approach, we identified a novel E3 ligase complex containing cullin 4B (CUL4B), DNA damage binding protein 1 (DDB1) and F-box protein 44 (FBXO44) that mediates RGS2 protein degradation. While the more typical F-box partners CUL1 and Skp1 can bind FBXO44, that E3 ligase complex does not bind RGS2 and is not involved in RGS2 degradation. These observations define an unexpected DDB1/CUL4B-containing FBXO44 E3 ligase complex. Pharmacological targeting of this mechanism provides a novel therapeutic approach to hypertension, anxiety, and other diseases associated with RGS2 dysregulation.
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Affiliation(s)
- Benita Sjögren
- Department of Pharmacology & Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, United States of America
| | - Steven Swaney
- Center for Chemical Genomics, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, United States of America
| | - Richard R Neubig
- Department of Pharmacology & Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, United States of America
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Kashina A. Protein arginylation, a global biological regulator that targets actin cytoskeleton and the muscle. Anat Rec (Hoboken) 2015; 297:1630-6. [PMID: 25125176 DOI: 10.1002/ar.22969] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 03/14/2014] [Indexed: 12/20/2022]
Abstract
Posttranslational addition of Arg to proteins, mediated by arginyltransferase ATE1 has been first observed in 1963 and remained poorly understood for decades since its original discovery. Recent work demonstrated the global nature of arginylation and its essential role in multiple physiological pathways during embryogenesis and adulthood and identified over a hundred of proteins arginylated in vivo. Among these proteins, the prominent role belongs to the actin cytoskeleton and the muscle, and follow up studies strongly suggests that arginylation constitutes a novel biological regulator of contractility. This review presents an overview of the studies of protein arginylation that led to the discovery of its major role in the muscle.
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Affiliation(s)
- Anna Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Stewart A, Maity B, Fisher RA. Two for the Price of One: G Protein-Dependent and -Independent Functions of RGS6 In Vivo. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:123-51. [PMID: 26123305 DOI: 10.1016/bs.pmbts.2015.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Regulator of G protein signaling 6 (RGS6) is unique among the members of the RGS protein family as it remains the only protein with the demonstrated capacity to control G protein-dependent and -independent signaling cascades in vivo. RGS6 inhibits signaling mediated by γ-aminobutyric acid B receptors, serotonin 1A receptors, μ opioid receptors, and muscarinic acetylcholine 2 receptors. RGS6 deletion triggers distinct behavioral phenotypes resulting from potentiated signaling by these G protein-coupled receptors namely ataxia, a reduction in anxiety and depression, enhanced analgesia, and increased parasympathetic tone, respectively. In addition, RGS6 possesses potent proapoptotic and growth suppressive actions. In heart, RGS6-dependent reactive oxygen species (ROS) production promotes doxorubicin (Dox)-induced cardiomyopathy, while in cancer cells RGS6/ROS signaling is necessary for activation of the ataxia telangiectasia mutated/p53/apoptosis pathway required for the chemotherapeutic efficacy of Dox. Further, by facilitating Tip60 (trans-acting regulator protein of HIV type 1-interacting protein 60 kDa)-dependent DNA methyltransferase 1 degradation, RGS6 suppresses cellular transformation in response to oncogenic Ras. The culmination of these G protein-independent actions results in potent tumor suppressor actions of RGS6 in the murine mammary epithelium. This work summarizes evidence from human genetic studies and model animals implicating RGS6 in normal physiology, disease, and the pharmacological actions of multiple drugs. Though efforts by multiple laboratories have contributed to the ever-growing RGS6 oeuvre, the pleiotropic nature of this gene will likely lead to additional work detailing the importance of RGS6 in neuropsychiatric disorders, cardiovascular disease, and cancer.
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Affiliation(s)
- Adele Stewart
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Biswanath Maity
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Rory A Fisher
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
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Abstract
Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway.
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Affiliation(s)
- Joost T van Dongen
- Institute of Biology I, Aachen Biology and Biotechnology, RWTH Aachen University, 52074 Aachen, Germany;
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Abstract
In 1980s it was found that addition of N-terminal Arg to proteins induces their ubiquitination and degradation by the N-end rule pathway. While this mechanism applies only to the proteins which also have other features of the N-degron (including a closely adjacent Lys that is accessible for ubiquitination), several test substrates have been found to follow this mechanism very efficiently after ATE1-dependent arginylation. Such property enabled researchers to test ATE1 activity in cells indirectly by assaying for the degradation of such arginylation-dependent substrates. The most commonly used substrate for this assay is E. coli beta galactosidase (beta-Gal) because its activity can be easily measured using standardized colorimetric assays. Here we describe this method, which has served as a quick and easy way to characterize ATE1 activity during identification of arginyltransferases in different species.
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Affiliation(s)
- Anna S Kashina
- Department of Animal Biology School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA, 19104, USA,
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Abstract
Posttranslational modifications have emerged in recent years as the major biological regulators responsible for the orders of magnitude increase in complexity of protein functions. These "molecular switches" affect nearly every protein in vivo by modulating their protein structure, activity, molecular interactions, and homeostasis. While over 350 protein modifications have been described, only a handful of them have been characterized. Until recently, protein arginylation has belonged to the list of obscure, poorly understood posttranslational modifications, before the recent explosion of studies has put arginylation on the map of intracellular metabolic pathways and biological processes. This chapter contains an overview of all the major milestones in the protein arginylation field, from its original discovery in 1963 to this day.
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Wydeven N, Posokhova E, Xia Z, Martemyanov KA, Wickman K. RGS6, but not RGS4, is the dominant regulator of G protein signaling (RGS) modulator of the parasympathetic regulation of mouse heart rate. J Biol Chem 2013; 289:2440-9. [PMID: 24318880 DOI: 10.1074/jbc.m113.520742] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Parasympathetic activity decreases heart rate (HR) by inhibiting pacemaker cells in the sinoatrial node (SAN). Dysregulation of parasympathetic influence has been linked to sinus node dysfunction and arrhythmia. RGS (regulator of G protein signaling) proteins are negative modulators of the parasympathetic regulation of HR and the prototypical M2 muscarinic receptor (M2R)-dependent signaling pathway in the SAN that involves the muscarinic-gated atrial K(+) channel IKACh. Both RGS4 and RGS6-Gβ5 have been implicated in these processes. Here, we used Rgs4(-/-), Rgs6(-/-), and Rgs4(-/-):Rgs6(-/-) mice to compare the relative influence of RGS4 and RGS6 on parasympathetic regulation of HR and M2R-IKACh-dependent signaling in the SAN. In retrogradely perfused hearts, ablation of RGS6, but not RGS4, correlated with decreased resting HR, increased heart rate variability, and enhanced sensitivity to the negative chronotropic effects of the muscarinic agonist carbachol. Similarly, loss of RGS6, but not RGS4, correlated with enhanced sensitivity of the M2R-IKACh signaling pathway in SAN cells to carbachol and a significant slowing of M2R-IKACh deactivation rate. Surprisingly, concurrent genetic ablation of RGS4 partially rescued some deficits observed in Rgs6(-/-) mice. These findings, together with those from an acute pharmacologic approach in SAN cells from Rgs6(-/-) and Gβ5(-/-) mice, suggest that the partial rescue of phenotypes in Rgs4(-/-):Rgs6(-/-) mice is attributable to another R7 RGS protein whose influence on M2R-IKACh signaling is masked by RGS4. Thus, RGS6-Gβ5, but not RGS4, is the primary RGS modulator of parasympathetic HR regulation and SAN M2R-IKACh signaling in mice.
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Affiliation(s)
- Nicole Wydeven
- From the Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455 and
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Monroy CA, Doorn JA, Roman DL. Modification and functional inhibition of regulator of G-protein signaling 4 (RGS4) by 4-hydroxy-2-nonenal. Chem Res Toxicol 2013; 26:1832-9. [PMID: 24229325 DOI: 10.1021/tx400212q] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidative stress has been implicated as a component of various pathologies including ischemia/reperfusion injury (IRI) and neurodegenerative diseases such as Parkinson's disease (PD) and schizophrenia. Similarly, regulator of G-protein signaling 4 (RGS4) has been implicated as an important player in each of these pathologies. RGS4, like other RGS proteins, is responsible for temporally regulating G-protein coupled receptor signaling by increasing the intrinsic GTPase activity of Gα subunit of the heterotrimeric signaling complex. In this study we evaluated whether modification by 4-hydroxy-2-nonenal (4HNE), a common lipid peroxidation product, inhibits RGS4. Using immunoprecipitation, we first determined RGS4 modification was occurring in cells at concentrations of 4HNE within reported physiological conditions. Following this determination, we evaluated modification of RGS4 by 4HNE by both Western blot and mass spectrometry (MS). Once it was established that covalent modification occurred only on cysteine containing constructs, tryptic digest followed by mass spectrometry analysis revealed modification occurs at cysteine residues 71, 148, and 183. In order to determine the effect 4HNE had on RGS4 activity, a steady-state colorimetric assay was used to analyze the GAP activity of Δ51-RGS4 as well as the cysteine null mutant. From the data, we determined that RGS4 activity can be modulated by 4HNE through modification at cysteine residues similar to previously reported small molecule inhibition of RGS4.
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Affiliation(s)
- C Aaron Monroy
- Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, University of Iowa College of Pharmacy , 115 South Grand Avenue, Iowa City, Iowa 52242, United States
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Li SJ, Li Y, Cui SC, Qi Y, Zhao JJ, Liu XY, Xu P, Chen XH. Splicing factor transformer-2β (Tra2β) regulates the expression of regulator of G protein signaling 4 (RGS4) gene and is induced by morphine. PLoS One 2013; 8:e72220. [PMID: 23977258 PMCID: PMC3747076 DOI: 10.1371/journal.pone.0072220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 07/08/2013] [Indexed: 12/19/2022] Open
Abstract
Regulator of G protein signaling 4 (RGS4) is a critical modulator of G protein-coupled receptor (GPCR)-mediated signaling and plays important roles in many neural process and diseases. Particularly, drug-induced alteration in RGS4 protein levels is associated with acute and chronic effects of drugs of abuse. However, the precise mechanism underlying the regulation of RGS4 expression is largely unknown. Here, we demonstrated that the expression of RGS4 gene was subject to regulation by alternative splicing of the exon 6. Transformer-2β (Tra2β), an important splicing factor, bound to RGS4 mRNA and increased the relative level of RGS4-1 mRNA isoform by enhancing the inclusion of exon 6. Meanwhile, Tra2β increased the expression of full-length RGS4 protein. In rat brain, Tra2β was co-localized with RGS4 in multiple opioid action-related brain regions. In addition, the acute and chronic morphine treatment induced alteration in the expression level of Tra2β in rat locus coerulus (LC) in parallel to that of RGS4 proteins. It suggests that induction of this splicing factor may contribute to the change of RGS4 level elicited by morphine. Taken together, the results provide the evidence demonstrating the function of Tra2β as a new mediator in opioid-induced signaling pathway via regulating RGS4 expression.
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Affiliation(s)
- Shu-Jing Li
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Laboratory of Genomic Physiology and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ya Li
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Shi-chao Cui
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yao Qi
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Jing-Jing Zhao
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xiao-Yan Liu
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ping Xu
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xian-Hua Chen
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Laboratory of Genomic Physiology and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
- * E-mail:
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Bastin G, Heximer SP. Rab family proteins regulate the endosomal trafficking and function of RGS4. J Biol Chem 2013; 288:21836-49. [PMID: 23733193 DOI: 10.1074/jbc.m113.466888] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RGS4, a heterotrimeric G-protein inhibitor, localizes to plasma membrane (PM) and endosomal compartments. Here, we examined Rab-mediated control of RGS4 internalization and recycling. Wild type and constitutively active Rab5 decreased RGS4 PM levels while increasing its endosomal targeting. Rab5, however, did not appreciably affect the PM localization or function of the M1 muscarinic receptor (M1R)/Gq signaling cascade. RGS4-containing endosomes co-localized with subsets of Rab5-, transferrin receptor-, and Lamp1/Lysotracker-marked compartments suggesting RGS4 traffics through PM recycling or acidified endosome pathways. Rab7 activity promoted TGN association, whereas Rab7(dominant negative) trapped RGS4 in late endosomes. Furthermore, RGS4 was found to co-localize with an endosomal pool marked by Rab11, the protein that mediates recycling/sorting of proteins to the PM. The Cys-12 residue in RGS4 appeared important for its Rab11-mediated trafficking to the PM. Rab11(dominant negative) decreased RGS4 PM levels and increased the number of RGS4-containing endosomes. Inhibition of Rab11 activity decreased RGS4 function as an inhibitor of M1R activity without affecting localization and function of the M1R/Gq signaling complex. Thus, both Rab5 activation and Rab11 inhibition decreased RGS4 function in a manner that is independent from their effects on the localization and function of the M1R/Gq signaling complex. This is the first study to implicate Rab GTPases in the intracellular trafficking of an RGS protein. Thus, Rab GTPases may be novel molecular targets for the selective regulation of M1R-mediated signaling via their specific effects on RGS4 trafficking and function.
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Affiliation(s)
- Guillaume Bastin
- Department of Physiology, Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Jaba IM, Zhuang ZW, Li N, Jiang Y, Martin KA, Sinusas AJ, Papademetris X, Simons M, Sessa WC, Young LH, Tirziu D. NO triggers RGS4 degradation to coordinate angiogenesis and cardiomyocyte growth. J Clin Invest 2013; 123:1718-31. [PMID: 23454748 DOI: 10.1172/jci65112] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 01/10/2013] [Indexed: 12/11/2022] Open
Abstract
Myocardial hypertrophy is an adaptation to increased hemodynamic demands. An increase in heart tissue must be matched by a corresponding expansion of the coronary vasculature to maintain and adequate supply of oxygen and nutrients for the heart. The physiological mechanisms that underlie the coordination of angiogenesis and cardiomyocyte growth are unknown. We report that induction of myocardial angiogenesis promotes cardiomyocyte growth and cardiac hypertrophy through a novel NO-dependent mechanism. We used transgenic, conditional overexpression of placental growth factor (PlGF) in murine cardiac tissues to stimulate myocardial angiogenesis and increase endothelial-derived NO release. NO production, in turn, induced myocardial hypertrophy by promoting proteasomal degradation of regulator of G protein signaling type 4 (RGS4), thus relieving the repression of the Gβγ/PI3Kγ/AKT/mTORC1 pathway that stimulates cardiomyocyte growth. This hypertrophic response was prevented by concomitant transgenic expression of RGS4 in cardiomyocytes. NOS inhibitor L-NAME also significantly attenuated RGS4 degradation, and reduced activation of AKT/mTORC1 signaling and induction of myocardial hypertrophy in PlGF transgenic mice, while conditional cardiac-specific PlGF expression in eNOS knockout mice did not induce myocardial hypertrophy. These findings describe a novel NO/RGS4/Gβγ/PI3Kγ/AKT mechanism that couples cardiac vessel growth with myocyte growth and heart size.
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Affiliation(s)
- Irina M Jaba
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut 06510, USA
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