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Zou JP, Zhao QF, Yang T, Shang YF, Ahammed GJ, Zhou J. The E3 ubiquitin ligase RING1 interacts with COP9 Signalosome Subunit 4 to positively regulate resistance to root-knot nematodes in Solanum lycopersicum L. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 322:111344. [PMID: 35659944 DOI: 10.1016/j.plantsci.2022.111344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/07/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Globally, root-knot nematodes (RKNs) cause massive production losses in all major crops. E3 ubiquitin ligases are involved in plant growth, development and immune response. But their roles in plant defense against RKNs are largely unclear. Here, we show that tomato E3 ubiquitin ligase RING1 interacts with COP9 Signalosome Subunit 4 (CSN4) which is essential for jasmonic acid (JA)-dependent basal defense against RKNs. Tissue-specific expression analysis showed that RING1 expression was the highest in tomato roots and the expression was significantly increased with RKN (Meloidogyne incognita) infection. Compared with the wild-type plants, the number of egg masses in roots significantly increased in the ring1 mutants, while RING1 overexpression conferred resistance against RKNs. Furthermore, RKN infection increased the accumulation of CSN4 protein in the roots of wild-type plants, which was largely compromised in the ring1 mutants but was enhanced in the RING1 overexpressing plants. The RKN-induced transcripts of JA biosynthetic and signaling genes as well as the accumulation of JA and JA-isoleucine were compromised in ring1 mutants but were increased in RING1 overexpressing plants. These results suggest that RING1 positively regulates JA-dependent basal defense against RKNs by interacting with CSN4 proteins.
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Affiliation(s)
- Jin-Ping Zou
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Qiu-Feng Zhao
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Ting Yang
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Yi-Fen Shang
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Golam Jalal Ahammed
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China
| | - Jie Zhou
- Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China; Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Yuhangtang Road 866, Hangzhou 310058, China; Shandong (Linyi) Institute of Modern Agriculture, Zhejiang University, Linyi 276000, China.
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Kaur A, Lee LH, Chow SC, Fang CM. IRF5-mediated immune responses and its implications in immunological disorders. Int Rev Immunol 2018; 37:229-248. [PMID: 29985675 DOI: 10.1080/08830185.2018.1469629] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Transcription factors are gene regulators that activate or repress target genes. One family of the transcription factors that have been extensively studied for their crucial role in regulating gene network in the immune system is the interferon regulatory factors (IRFs). IRFs possess a novel turn-helix turn motif that recognizes a specific DNA consensus found in the promoters of many genes that are involved in immune responses. IRF5, a member of IRFs has recently gained much attention for its role in regulating inflammatory responses and autoimmune diseases. Here, we discuss the role of IRF5 in regulating immune cells functions and how the dysregulation of IRF5 contributes to the pathogenesis of immune disorders. We also review the latest findings of potential IRF5 inhibitors that modulate IRF5 activity in the effort of developing therapeutic approaches for treating inflammatory disorders.
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Affiliation(s)
- Ashwinder Kaur
- a School of Pharmacy, Faculty of Science , The University of Nottingham Malaysia Campus , Selangor Darul , Ehsan , Malaysia
| | - Learn-Han Lee
- c School of Pharmacy , Monash University Malaysia , Selangor Darul , Ehsan , Malaysia.,e Jeffrey Cheah School of Medicine and Health Sciences , Monash University Malaysia , Selangor Darul , Ehsan , Malaysia
| | - Sek-Chuen Chow
- d School of Science , Monash University Malaysia , Selangor Darul , Ehsan , Malaysia
| | - Chee-Mun Fang
- b Department of Biomedical Sciences, Faculty of Science , The University of Nottingham Malaysia Campus , Selangor Darul , Ehsan , Malaysia
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Mishra R, Upadhyay A, Prajapati VK, Mishra A. Proteasome-mediated proteostasis: Novel medicinal and pharmacological strategies for diseases. Med Res Rev 2018; 38:1916-1973. [DOI: 10.1002/med.21502] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/13/2018] [Accepted: 04/04/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Ribhav Mishra
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
| | - Vijay Kumar Prajapati
- Department of Biochemistry; School of Life Sciences; Central University of Rajasthan; Rajasthan India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
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Zhao SC, Wang C, Xu H, Wu WQ, Chu ZH, Ma LS, Zhang YD, Liu F. Age-related differences in interferon regulatory factor-4 and -5 signaling in ischemic brains of mice. Acta Pharmacol Sin 2017; 38:1425-1434. [PMID: 28905935 DOI: 10.1038/aps.2017.122] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/30/2017] [Indexed: 02/07/2023] Open
Abstract
Stroke is a disease that mainly affects the elderly. Since the age-related differences in stroke have not been well studied, modeling stroke in aged animals is clinically more relevant. The inflammatory responses to stroke are a fundamental pathological procedure, in which microglial activation plays an important role. Interferon regulatory factor-5 (IRF5) and IRF4 regulate M1 and M2 activation of macrophages, respectively, in peripheral inflammation; but it is unknown whether IRF5/IRF4 are also involved in cerebral inflammatory responses to stroke and whether age-related differences of the IRF5/IRF4 signaling exist in ischemic brain. Here, we investigated the influences of aging on IRF5/IRF4 signaling and post-stroke inflammation in mice. Both young (9-12 weeks) and aged (18 months) male mice were subjected to middle cerebral artery occlusion (MCAO). Morphological and biochemical changes in the ischemic brains and behavior deficits were assessed on 1, 3, and 7 d post-stroke. After MCAO, the aged mice showed smaller infarct sizes but higher neurological deficits and corner test scores than young mice. Young mice had higher levels of IRF4 and CD206 microglia in the ischemic brains, whereas the aged mice expressed more IRF5 and MHCII microglia. After MCAO, serum pro-inflammatory cytokines (TNF-α, iNOS, IL-6) were more prominently up-regulated in aged mice, whereas serum anti-inflammatory cytokines (TGF-β, IL-4, IL-10) were more prominently up-regulated in young mice. Our results demonstrate that aging has a significant influence on stroke outcomes in mice, which is probably mediated by age-specific inflammatory responses.
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Gaspar L, Howald C, Popadin K, Maier B, Mauvoisin D, Moriggi E, Gutierrez-Arcelus M, Falconnet E, Borel C, Kunz D, Kramer A, Gachon F, Dermitzakis ET, Antonarakis SE, Brown SA. The genomic landscape of human cellular circadian variation points to a novel role for the signalosome. eLife 2017; 6:e24994. [PMID: 28869038 PMCID: PMC5601996 DOI: 10.7554/elife.24994] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 09/01/2017] [Indexed: 11/18/2022] Open
Abstract
The importance of natural gene expression variation for human behavior is undisputed, but its impact on circadian physiology remains mostly unexplored. Using umbilical cord fibroblasts, we have determined by genome-wide association how common genetic variation impacts upon cellular circadian function. Gene set enrichment points to differences in protein catabolism as one major source of clock variation in humans. The two most significant alleles regulated expression of COPS7B, a subunit of the COP9 signalosome. We further show that the signalosome complex is imported into the nucleus in timed fashion to stabilize the essential circadian protein BMAL1, a novel mechanism to oppose its proteasome-mediated degradation. Thus, circadian clock properties depend in part upon a genetically-encoded competition between stabilizing and destabilizing forces, and genetic alterations in these mechanisms provide one explanation for human chronotype.
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Affiliation(s)
- Ludmila Gaspar
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
| | - Cedric Howald
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Konstantin Popadin
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
| | - Bert Maier
- Charité–UniversitätsmedizinLaboratory of ChronobiologyBerlinGermany
| | - Daniel Mauvoisin
- Department of Pharmacology and ToxicologyUniversity of LausanneLausanneSwitzerland
| | - Ermanno Moriggi
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
| | - Maria Gutierrez-Arcelus
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Emilie Falconnet
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Christelle Borel
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Dieter Kunz
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Working Group Sleep Research & Clinical ChronobiologyBerlinGermany
| | - Achim Kramer
- Charité–UniversitätsmedizinLaboratory of ChronobiologyBerlinGermany
| | - Frederic Gachon
- Department of Pharmacology and ToxicologyUniversity of LausanneLausanneSwitzerland
| | - Emmanouil T Dermitzakis
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Steven A Brown
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
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Fu B, Zhao M, Wang L, Patil G, Smith JA, Juncadella IJ, Zuvela-Jelaska L, Dorf ME, Li S. RNAi Screen and Proteomics Reveal NXF1 as a Novel Regulator of IRF5 Signaling. Sci Rep 2017; 7:2683. [PMID: 28578407 PMCID: PMC5457443 DOI: 10.1038/s41598-017-02857-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 04/20/2017] [Indexed: 01/25/2023] Open
Abstract
Interferon regulatory factor 5 (IRF5) is a key transcription factor of innate immunity, which plays an important role in host restriction to viral infection and inflammation. Genome-wide association studies have implied the association of IRF5 with several autoimmune diseases, including systemic lupus erythematosus (SLE), Sjogren's syndrome, inflammatory bowel disease and multiple sclerosis. However, the regulation of IRF5-mediated immunity is not well understood. To uncover new regulators in IRF5 pathway, we used two "omics" approaches: affinity purification coupled with mass spectrometry and a high throughput RNAi screen. Proteomics identified 16 new IRF5 interactors while RNAi-mediated knockdown found 43 regulators of the TLR7-dependent IRF5 signaling pathway. NXF1 was identified in both screens. Stimulation with TLR7 ligand enhances formation of IRF5-NXF1 protein complexes. Gain or loss-of-function experiments revealed NXF1 selectively regulates TLR7-driven IRF5 transcriptional activity, suggesting a new role for NXF1 in the IRF5 signaling pathway.
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Affiliation(s)
- Bishi Fu
- Department of Microbiology & Immunobiology, Harvard Medical School, Boston, Massachusetts, 02115, USA.,College of Life Science, Yangtze University, Jingzhou, Hubei, 434025, People's Republic of China
| | - Mengmeng Zhao
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, 74078, USA
| | - Lingyan Wang
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, 74078, USA
| | - Girish Patil
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, 74078, USA
| | - Jennifer A Smith
- Department of Microbiology & Immunobiology, Harvard Medical School, Boston, Massachusetts, 02115, USA.,ICCB-Longwood Screening Facility, Harvard Medical School, Boston, Massachusetts, 02115, USA
| | - Ignacio J Juncadella
- Department of Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, Connecticut, 06877, USA
| | - Ljiljana Zuvela-Jelaska
- Department of Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, Connecticut, 06877, USA
| | - Martin E Dorf
- Department of Microbiology & Immunobiology, Harvard Medical School, Boston, Massachusetts, 02115, USA.
| | - Shitao Li
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, 74078, USA.
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Zhao SC, Ma LS, Chu ZH, Xu H, Wu WQ, Liu F. Regulation of microglial activation in stroke. Acta Pharmacol Sin 2017; 38:445-458. [PMID: 28260801 DOI: 10.1038/aps.2016.162] [Citation(s) in RCA: 253] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/06/2016] [Indexed: 12/16/2022] Open
Abstract
When ischemic stroke occurs, oxygen and energy depletion triggers a cascade of events, including inflammatory responses, glutamate excitotoxicity, oxidative stress, and apoptosis that result in a profound brain injury. The inflammatory response contributes to secondary neuronal damage, which exerts a substantial impact on both acute ischemic injury and the chronic recovery of the brain function. Microglia are the resident immune cells in the brain that constantly monitor brain microenvironment under normal conditions. Once ischemia occurs, microglia are activated to produce both detrimental and neuroprotective mediators, and the balance of the two counteracting mediators determines the fate of injured neurons. The activation of microglia is defined as either classic (M1) or alternative (M2): M1 microglia secrete pro-inflammatory cytokines (TNFα, IL-23, IL-1β, IL-12, etc) and exacerbate neuronal injury, whereas the M2 phenotype promotes anti-inflammatory responses that are reparative. It has important translational value to regulate M1/M2 microglial activation to minimize the detrimental effects and/or maximize the protective role. Here, we discuss various regulators of microglia/macrophage activation and the interaction between microglia and neurons in the context of ischemic stroke.
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Specific detection of interferon regulatory factor 5 (IRF5): A case of antibody inequality. Sci Rep 2016; 6:31002. [PMID: 27481535 PMCID: PMC4969615 DOI: 10.1038/srep31002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/11/2016] [Indexed: 12/22/2022] Open
Abstract
Interferon regulatory factor 5 (IRF5) is a member of the IRF family of transcription factors. IRF5 was first identified and characterized as a transcriptional regulator of type I interferon expression after virus infection. In addition to its critical role(s) in the regulation and development of host immunity, subsequent studies revealed important roles for IRF5 in autoimmunity, cancer, obesity, pain, cardiovascular disease, and metabolism. Based on these important disease-related findings, a large number of commercial antibodies have become available to study the expression and function of IRF5. Here we validate a number of these antibodies for the detection of IRF5 by immunoblot, flow cytometry, and immunofluorescence or immunohistochemistry using well-established positive and negative controls. Somewhat surprising, the majority of commercial antibodies tested were unable to specifically recognize human or mouse IRF5. We present data on antibodies that do specifically recognize human or mouse IRF5 in a particular application. These findings reiterate the importance of proper controls and molecular weight standards for the analysis of protein expression. Given that dysregulated IRF5 expression has been implicated in the pathogenesis of numerous diseases, including autoimmune and cancer, results indicate that caution should be used in the evaluation and interpretation of IRF5 expression analysis.
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9
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Yuan R, Geng S, Chen K, Diao N, Chu HW, Li L. Low-grade inflammatory polarization of monocytes impairs wound healing. J Pathol 2016; 238:571-83. [PMID: 26690561 DOI: 10.1002/path.4680] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/06/2015] [Accepted: 12/02/2015] [Indexed: 01/05/2023]
Abstract
Impaired wound healing often accompanies low-grade inflammatory conditions, during which circulating levels of subclinical super-low-dose endotoxin may persist. Low-grade inflammatory monocyte polarization may occur during chronic inflammation and deter effective wound repair. However, little is understood about the potential mechanisms of monocyte polarization by sustained insult of subclinical super-low-dose endotoxin. We observed that super-low-dose endotoxin preferentially programmes a low-grade inflammatory monocyte state in vitro and in vivo, as represented by the elevated population of CD11b(+) Ly6C(high) monocytes and sustained expression of CCR5. Mechanistically, super-low-dose endotoxin caused cellular stress, altered lysosome function and increased the transcription factor IRF5. TUDCA, a potent inhibitor of cellular stress, effectively blocked monocyte polarization and improved wound healing in mice injected with super-low-dose endotoxin. Our data revealed the polarization of low-grade inflammatory monocytes by sustained endotoxin challenge, its underlying mechanisms and a potential intervention strategy. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Ruoxi Yuan
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Shuo Geng
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Keqiang Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Na Diao
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Hong Wei Chu
- Department of Medicine, National Jewish Health, Denver, CO, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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Pimenta EM, Barnes BJ. A conserved region within interferon regulatory factor 5 controls breast cancer cell migration through a cytoplasmic and transcription-independent mechanism. Mol Cancer 2015; 14:32. [PMID: 25649192 PMCID: PMC4326371 DOI: 10.1186/s12943-015-0305-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 01/27/2015] [Indexed: 01/07/2023] Open
Abstract
Background Migration of breast cancer cells out of a duct or lobule is a prerequisite for invasion and metastasis. However, the factors controlling breast cancer cell migration are not fully elucidated. We previously found that expression of the transcription factor interferon regulatory factor 5 (IRF5) is significantly decreased as a breast lesion progresses from a non-malignant stage to ductal carcinoma in situ and is eventually lost in ~80% of invasive ductal carcinomas examined. Human in vitro and murine in vivo models of invasive breast cancer confirmed an important role for IRF5 in regulating cell motility, invasion and/or metastasis; yet, the mechanism(s) by which this occurs is not known. Since IRF5 is primarily expressed in the cytoplasm of human mammary epithelial cells, we hypothesized that IRF5 may function in a transcription-independent manner to control intrinsic cell migration. Results A series of IRF5 deletion mutants were tested in cell motility, invasion and migration assays. A novel, conserved 10 amino acid domain was identified that regulates mammary epithelial cell migration. This region (∆115-125) is downstream of IRF5′s DNA binding domain and therefore when absent, retains IRF5 transcription activity but loses cell migration control. An IRF5 construct with a mutated nuclear localization signal further confirmed that IRF5 controls migration in a cytoplasmic and transcription-independent manner. Candidate cytoskeletal molecules were identified in MDA-MB-231 cells to interact with IRF5 by immunoprecipitation and mass spectrometry analysis. α6-tubulin was independently confirmed to interact with endogenous IRF5 in MCF-10A cells. Alterations in F-actin bundling after staining EV- and IRF5-231 cells with phalloidin suggests that IRF5 may control cell migration/motility through its interaction with cytoskeletal molecules that contribute to the formation of F-actin networks. Last and most notably, we found that IRF5′s control of cell migration is not restricted to mammary epithelial cells but functions in other epithelial cell types suggesting a more global role for this newly identified cell migratory function of IRF5. Conclusions These findings are significant as they identify a new regulator of epithelial cell migration and provide specific insight into the mechanism(s) by which loss of IRF5 expression in mammary epithelial cells contributes to breast cancer metastasis.
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Affiliation(s)
- Erica Maria Pimenta
- Department of Microbiology, Biochemistry & Molecular Genetics, Rutgers Biomedical and Health Sciences, Newark, NJ, 07103, USA. .,Rutgers Biomedical and Health Sciences, New Jersey Medical School-Cancer Center Rm. G1224, 205 South Orange Ave, Newark, NJ, 07103, USA.
| | - Betsy J Barnes
- Department of Microbiology, Biochemistry & Molecular Genetics, Rutgers Biomedical and Health Sciences, Newark, NJ, 07103, USA. .,Rutgers Biomedical and Health Sciences, New Jersey Medical School-Cancer Center Rm. G1224, 205 South Orange Ave, Newark, NJ, 07103, USA.
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Ryzhakov G, Eames HL, Udalova IA. Activation and Function of Interferon Regulatory Factor 5. J Interferon Cytokine Res 2015; 35:71-8. [DOI: 10.1089/jir.2014.0023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Grigory Ryzhakov
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Hayley L. Eames
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Irina A. Udalova
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
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TRIpartite motif 21 (TRIM21) differentially regulates the stability of interferon regulatory factor 5 (IRF5) isoforms. PLoS One 2014; 9:e103609. [PMID: 25084355 PMCID: PMC4118895 DOI: 10.1371/journal.pone.0103609] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 11/19/2022] Open
Abstract
IRF5 is a member of the Interferon Regulatory Factor (IRF) family of transcription factors activated downstream of the Toll-Like receptors (TLRs). Polymorphisms in IRF5 have been shown to be associated with the autoimmune disease Systemic Lupus Erythematosus (SLE) and other autoimmune conditions, suggesting a central role for IRF5 in the regulation of the immune response. Four different IRF5 isoforms originate due to alternative splicing and to the presence or absence of a 30 nucleotide insertion in IRF5 exon 6. Since the polymorphic region disturbs a PEST domain, a region associated with protein degradation, we hypothesized that the isoforms bearing the insertion might have increased stability, thus explaining the association of individual IRF5 isoforms with SLE. As the E3 ubiquitin ligase TRIpartite Motif 21 (TRIM21) has been shown to regulate the stability and hence activity of members of the IRF family, we investigated whether IRF5 is subjected to regulation by TRIM21 and whether dysregulation of this mechanism could explain the association of IRF5 with SLE. Our results show that IRF5 is degraded following TLR7 activation and that TRIM21 is involved in this process. Comparison of the individual IRF5 variants demonstrates that isoforms generated by alternative splicing are resistant to TRIM21-mediated degradation following TLR7 stimulation, thus providing a functional link between isoforms expression and stability/activity which contributes to explain the association of IRF5 with SLE.
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13
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Cheng X, Ratner L. HIV-2 Vpx protein interacts with interferon regulatory factor 5 (IRF5) and inhibits its function. J Biol Chem 2014; 289:9146-57. [PMID: 24532789 DOI: 10.1074/jbc.m113.534321] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interferon regulatory factor (IRF) family members have been implicated as critical transcription factors that function in immune responses, hematopoietic differentiation, and cell growth regulation. Activation of IRF5 results in the production of pro-inflammatory cytokines such as TNFα, IL6, and IL12, as well as type I interferons. In this study, we demonstrate that HIV-2 Vpx interacts with IRF5, and Vpx inhibits IRF5-mediated transactivation. Expression of Vpx in THP-1 cells reduced mRNA levels and protein production of Toll-like receptor-dependent IL6, IL12p40, and TNFα induced by lipopolysaccharide, R848, and ODN2216. Chromatin immunoprecipitation assays show that Vpx expression results in decreased promoter binding activity of IRF5. This study provides new insights into mechanisms employed by HIV-2 to counteract innate immune defenses against viral infection.
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Affiliation(s)
- Xiaogang Cheng
- From the Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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