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Valle-Mendiola A, Gutiérrez-Hoya A, Soto-Cruz I. JAK/STAT Signaling and Cervical Cancer: From the Cell Surface to the Nucleus. Genes (Basel) 2023; 14:1141. [PMID: 37372319 DOI: 10.3390/genes14061141] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/13/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway constitutes a rapid signaling module from the cell surface to the nucleus, and activates different cellular responses, such as proliferation, survival, migration, invasion, and inflammation. When the JAK/STAT pathway is altered, it contributes to cancer progression and metastasis. STAT proteins play a central role in developing cervical cancer, and inhibiting the JAK/STAT signaling may be necessary to induce tumor cell death. Several cancers show continuous activation of different STATs, including cervical cancer. The constitutive activation of STAT proteins is associated with a poor prognosis and overall survival. The human papillomavirus (HPV) oncoproteins E6 and E7 play an essential role in cervical cancer progression, and they activate the JAK/STAT pathway and other signals that induce proliferation, survival, and migration of cancer cells. Moreover, there is a crosstalk between the JAK/STAT signaling cascade with other signaling pathways, where a plethora of different proteins activate to induce gene transcription and cell responses that contribute to tumor growth. Therefore, inhibition of the JAK/STAT pathway shows promise as a new target in cancer treatment. In this review, we discuss the role of the JAK/STAT pathway components and the role of the HPV oncoproteins associated with cellular malignancy through the JAK/STAT proteins and other signaling pathways to induce tumor growth.
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Affiliation(s)
- Arturo Valle-Mendiola
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
| | - Adriana Gutiérrez-Hoya
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
- Cátedra CONACYT, FES Zaragoza, National University of Mexico, Mexico City 09230, Mexico
| | - Isabel Soto-Cruz
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
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2
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Chin L, Wong CYG, Gill H. Targeting and Monitoring Acute Myeloid Leukaemia with Nucleophosmin-1 ( NPM1) Mutation. Int J Mol Sci 2023; 24:3161. [PMID: 36834572 PMCID: PMC9958584 DOI: 10.3390/ijms24043161] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023] Open
Abstract
Mutations in NPM1, also known as nucleophosmin-1, B23, NO38, or numatrin, are seen in approximately one-third of patients with acute myeloid leukaemia (AML). A plethora of treatment strategies have been studied to determine the best possible approach to curing NPM1-mutated AML. Here, we introduce the structure and function of NPM1 and describe the application of minimal residual disease (MRD) monitoring using molecular methods by means of quantitative polymerase chain reaction (qPCR), droplet digital PCR (ddPCR), next-generation sequencing (NGS), and cytometry by time of flight (CyTOF) to target NPM1-mutated AML. Current drugs, now regarded as the standard of care for AML, as well as potential drugs still under development, will also be explored. This review will focus on the role of targeting aberrant NPM1 pathways such as BCL-2 and SYK; as well as epigenetic regulators (RNA polymerase), DNA intercalators (topoisomerase II), menin inhibitors, and hypomethylating agents. Aside from medication, the effects of stress on AML presentation have been reported, and some possible mechanisms outlined. Moreover, targeted strategies will be briefly discussed, not only for the prevention of abnormal trafficking and localisation of cytoplasmic NPM1 but also for the elimination of mutant NPM1 proteins. Lastly, the advancement of immunotherapy such as targeting CD33, CD123, and PD-1 will be mentioned.
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Affiliation(s)
| | | | - Harinder Gill
- Department of Medicine, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China
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3
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Chen X, Chen J, Chen R, Mou H, Sun G, Yang L, Jia Y, Zhao Q, Wen W, Zhou L, Ding Y, Tang X, Yang J, An Y, Zhao X. Genetic and Functional Identifying of Novel STAT1 Loss-of-Function Mutations in Patients with Diverse Clinical Phenotypes. J Clin Immunol 2022; 42:1778-1794. [PMID: 35976469 DOI: 10.1007/s10875-022-01339-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE Mutations in signal transducer and activator of transcription 1 (STAT1) cause a broad spectrum of disease phenotypes. Heterozygous STAT1 loss-of-function (LOF) mutations cause Mendelian susceptibility to mycobacterial diseases (MSMD) infection, which is attributable to impaired IFN-γ signaling. The identification of novel mutations may extend the phenotypes associated with autosomal dominant (AD) STAT1 deficiency. METHODS Five patients with heterozygous STAT1 variations were recruited and their clinical and immunologic phenotypes were analyzed, with particular reference to JAK-STAT1 signaling pathways. RESULTS Four, heterozygous STAT1 deficiency mutations were identified, three of which were novel mutations. Two of the mutations were previously unreported mRNA splicing mutations in AD STAT1-deficient patients. Patients with heterozygous STAT1 deficiency suffered not only mycobacterial infection, but also intracellular non-mycobacterial bacterial infection and congenital multiple malformations. AD-LOF mutation impaired IFN-γ-mediated STAT1 phosphorylation, gamma-activated sequence (GAS), and IFN-stimulated response element (ISRE) transcription activity and IFN-induced gene expression to different extents, which might account for the diverse clinical manifestations observed in these patients. CONCLUSION The infectious disease susceptibility and phenotypic spectrum of patients with AD STAT1-LOF are broader than simply MSMD. The susceptibility to infections and immunological deficiency phenotypes, observed in AD-LOF patients, confirms the importance of STAT1 in host-pathogen interaction and immunity. However, variability in the nature and extent of these phenotypes suggests that functional analysis is required to identify accurately novel, heterozygous STAT1 mutations, associated with pathogenicity. Aberrant splice of STAT1 RNA could result in AD-LOF for STAT1 signaling which need more cases for confirmation.
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Affiliation(s)
- Xuemei Chen
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Junjie Chen
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Ran Chen
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Huilin Mou
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Gan Sun
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Lu Yang
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Yanjun Jia
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Qin Zhao
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Wen Wen
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Lina Zhou
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Yuan Ding
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Xuemei Tang
- Department of Rheumatology and Immunology, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Jun Yang
- Department of Rheumatology and Immunology, Shenzhen Children's Hospital, Shenzhen, 518000, China
| | - Yunfei An
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China. .,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China. .,Department of Rheumatology and Immunology, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
| | - Xiaodong Zhao
- Department of Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China. .,Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China. .,Department of Rheumatology and Immunology, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
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4
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Yang H, Sinha N, Rand U, Hauser H, Köster M, de Greef TFA, Tel J. A universal microfluidic approach for integrated analysis of temporal homocellular and heterocellular signaling and migration dynamics. Biosens Bioelectron 2022; 211:114353. [PMID: 35594624 DOI: 10.1016/j.bios.2022.114353] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 05/06/2022] [Indexed: 11/24/2022]
Abstract
Microfluidics offers precise and dynamic control of microenvironments for the study of temporal cellular responses. However, recent research focusing solely on either homocellular (single-cell, population) or heterocellular response may yield insufficient output, which possibly leads to partial comprehension about the underlying mechanisms of signaling events and corresponding cellular behaviors. Here, a universal microfluidic approach is developed for integrated analysis of temporal signaling and cell migration dynamics in multiple cellular contexts (single-cell, population and coculture). This approach allows to confine the desired number or mixture of specific cell sample types in a single device. Precise single cell seeding was achieved manually with bidirectional controllability. Coupled with time-lapse imaging, temporal cellular responses can be observed with single-cell resolution. Using NIH3T3 cells stably expressing signal transducer and activator of transcription 1/2 (STAT1/2) activity biosensors, temporal STAT1/2 activation and cell migration dynamics were explored in isolated single cells, populations and cocultures stimulated with temporal inputs, such as single-pulse and continuous signals of interferon γ (IFNγ) or lipopolysaccharide (LPS). We demonstrate distinct dynamic responses of fibroblasts in different cellular contexts. Our presented approach facilitates a multi-dimensional understanding of STAT signaling and corresponding migration behaviors.
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Affiliation(s)
- Haowen Yang
- Laboratory of Immunoengineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5600 MB, the Netherlands
| | - Nidhi Sinha
- Laboratory of Immunoengineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5600 MB, the Netherlands
| | - Ulfert Rand
- Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Hansjörg Hauser
- Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Mario Köster
- Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Tom F A de Greef
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5600 MB, the Netherlands; Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, 5600MB, Eindhoven, the Netherlands
| | - Jurjen Tel
- Laboratory of Immunoengineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5600 MB, the Netherlands.
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5
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Manokaran G, Audsley MD, Funakoda H, David CT, Garnham KA, Rawlinson SM, Deffrasnes C, Ito N, Moseley GW. Deactivation of the antiviral state by rabies virus through targeting and accumulation of persistently phosphorylated STAT1. PLoS Pathog 2022; 18:e1010533. [PMID: 35576230 PMCID: PMC9135343 DOI: 10.1371/journal.ppat.1010533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 05/26/2022] [Accepted: 04/19/2022] [Indexed: 12/25/2022] Open
Abstract
Antagonism of the interferon (IFN)-mediated antiviral state is critical to infection by rabies virus (RABV) and other viruses, and involves interference in the IFN induction and signaling pathways in infected cells, as well as deactivation of the antiviral state in cells previously activated by IFN. The latter is required for viral spread in the host, but the precise mechanisms involved and roles in RABV pathogenesis are poorly defined. Here, we examined the capacity of attenuated and pathogenic strains of RABV that differ only in the IFN-antagonist P protein to overcome an established antiviral state. Importantly, P protein selectively targets IFN-activated phosphorylated STAT1 (pY-STAT1), providing a molecular tool to elucidate specific roles of pY-STAT1. We find that the extended antiviral state is dependent on a low level of pY-STAT1 that appears to persist at a steady state through ongoing phosphorylation/dephosphorylation cycles, following an initial IFN-induced peak. P protein of pathogenic RABV binds and progressively accumulates pY-STAT1 in inactive cytoplasmic complexes, enabling recovery of efficient viral replication over time. Thus, P protein-pY-STAT1 interaction contributes to ‘disarming’ of the antiviral state. P protein of the attenuated RABV is defective in this respect, such that replication remains suppressed over extended periods in cells pre-activated by IFN. These data provide new insights into the nature of the antiviral state, indicating key roles for residual pY-STAT1 signaling. They also elucidate mechanisms of viral deactivation of antiviral responses, including specialized functions of P protein in selective targeting and accumulation of pY-STAT1. Following viral infection, the host activates multiple antiviral defenses. The ability of viruses to overcome these defenses is critical to disease. The earliest antiviral response involves the production of interferon messenger molecules. Interferons act on infected cells to inhibit viral proliferation, as well as on non-infected cells to establish an antiviral state before infection and so limit viral spread through the host organism. Many strategies used by viruses to overcome the former are well understood, but mechanisms important to the latter, and their importance to disease, are less well defined. In this study, we investigated how rabies virus overcomes a pre-established antiviral state in target cells. We found that the capacity to disable the antiviral state correlates with the ability to cause disease, and involves binding of a viral protein to cellular signaling proteins, which our data indicate are responsible for the maintenance of a prolonged antiviral state. This advances our understanding of antiviral responses, and identifies a key step in lethal infection by rabies virus that causes approximately 60,000 human deaths per year. The findings may contribute to new approaches for the development of vaccines or antivirals.
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Affiliation(s)
- Gayathri Manokaran
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Michelle D. Audsley
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Haruka Funakoda
- Laboratory of Zoonotic Diseases, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Cassandra T. David
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Katherine A. Garnham
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Stephen M. Rawlinson
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Celine Deffrasnes
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Naoto Ito
- Laboratory of Zoonotic Diseases, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
- * E-mail: (NI); (GWM)
| | - Gregory W. Moseley
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
- * E-mail: (NI); (GWM)
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6
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Abstract
Understanding autophagy regulation is instrumental in developing therapeutic interventions for autophagy-associated disease. Here, we identified SNAI2 as a regulator of autophagy from a genome-wide screen in HeLa cells. Upon energy stress, SNAI2 is transcriptionally activated by FOXO3 and interacts with FOXO3 to form a feed-forward regulatory loop to reinforce the expression of autophagy genes. Of note, SNAI2-increased FOXO3-DNA binding abrogates CRM1-dependent FOXO3 nuclear export, illuminating a pivotal role of DNA in the nuclear retention of nucleocytoplasmic shuttling proteins. Moreover, a dFoxO-Snail feed-forward loop regulates both autophagy and cell size in Drosophila, suggesting this evolutionarily conserved regulatory loop is engaged in more physiological activities. Autophagy is a highly conserved programmed degradation process that regulates a variety of physiological and pathological activities in health, aging, and disease. To identify additional factors that modulate autophagy, we utilized serum-free starvation or Torin1 to induce autophagy in HeLa cells for unbiased mRNA-sequencing analysis and identified SNAI2, a crucial player in epithelial-to-mesenchymal transition and cancer progression, as a regulator of autophagy. Mechanistically, SNAI2 promotes autophagy by physically interacting with FOXO3 and enhancing FOXO3 binding affinity to its response elements in autophagy-related genes. Intriguingly, binding to the DNA targets appears necessary and sufficient for FOXO3 to antagonize its CRM1-dependent nuclear export, illustrating a critical role of DNA in regulating protein nuclear localization. Moreover, stress-elevated SNAI2 expression is mediated by FOXO3, which activates SNAI2 transcription by directly binding to its promoter. Herein, FOXO3 and SNAI2 form a coherent feed-forward regulatory loop to reinforce autophagy genes induction in response to energy stress. Strikingly, a dFoxO-Snail feed-forward circuit also regulates autophagy in Drosophila, suggesting this mechanism is evolutionarily conserved from fly to human.
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7
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Xue W, Ding C, Qian K, Liao Y. The Interplay Between Coronavirus and Type I IFN Response. Front Microbiol 2022; 12:805472. [PMID: 35317429 PMCID: PMC8934427 DOI: 10.3389/fmicb.2021.805472] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/24/2021] [Indexed: 12/14/2022] Open
Abstract
In the past few decades, newly evolved coronaviruses have posed a global threat to public health and animal breeding. To control and prevent the coronavirus-related diseases, understanding the interaction of the coronavirus and the host immune system is the top priority. Coronaviruses have evolved multiple mechanisms to evade or antagonize the host immune response to ensure their replication. As the first line and main component of innate immune response, type I IFN response is able to restrict virus in the initial infection stage; it is thus not surprising that the primary aim of the virus is to evade or antagonize the IFN response. Gaining a profound understanding of the interaction between coronaviruses and type I IFN response will shed light on vaccine development and therapeutics. In this review, we provide an update on the current knowledge on strategies employed by coronaviruses to evade type I IFN response.
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Affiliation(s)
- Wenxiang Xue
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chan Ding
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Kun Qian
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
- *Correspondence: Ying Liao,
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8
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Topolewski P, Zakrzewska KE, Walczak J, Nienałtowski K, Müller-Newen G, Singh A, Komorowski M. Phenotypic variability, not noise, accounts for most of the cell-to-cell heterogeneity in IFN-γ and oncostatin M signaling responses. Sci Signal 2022; 15:eabd9303. [PMID: 35167339 DOI: 10.1126/scisignal.abd9303] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cellular signaling responses show substantial cell-to-cell heterogeneity, which is often ascribed to the inherent randomness of biochemical reactions, termed molecular noise, wherein high noise implies low signaling fidelity. Alternatively, heterogeneity could arise from differences in molecular content between cells, termed molecular phenotypic variability, which does not necessarily imply imprecise signaling. The contribution of these two processes to signaling heterogeneity is unclear. Here, we fused fibroblasts to produce binuclear syncytia to distinguish noise from phenotypic variability in the analysis of cytokine signaling. We reasoned that the responses of the two nuclei within one syncytium could approximate the signaling outcomes of two cells with the same molecular content, thereby disclosing noise contribution, whereas comparison of different syncytia should reveal contribution of phenotypic variability. We found that ~90% of the variance in the primary response (which was the abundance of phosphorylated, nuclear STAT) to stimulation with the cytokines interferon-γ and oncostatin M resulted from differences in the molecular content of individual cells. Thus, our data reveal that cytokine signaling in the system used here operates in a reproducible, high-fidelity manner.
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Affiliation(s)
- Piotr Topolewski
- Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Karolina E Zakrzewska
- Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Jarosław Walczak
- Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Karol Nienałtowski
- Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, 52074 Aachen, Germany
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716, USA
| | - Michał Komorowski
- Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
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9
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Shen Q, Wang YE, Palazzo AF. Crosstalk between nucleocytoplasmic trafficking and the innate immune response to viral infection. J Biol Chem 2021; 297:100856. [PMID: 34097873 PMCID: PMC8254040 DOI: 10.1016/j.jbc.2021.100856] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
The nuclear pore complex is the sole gateway connecting the nucleoplasm and cytoplasm. In humans, the nuclear pore complex is one of the largest multiprotein assemblies in the cell, with a molecular mass of ∼110 MDa and consisting of 8 to 64 copies of about 34 different nuclear pore proteins, termed nucleoporins, for a total of 1000 subunits per pore. Trafficking events across the nuclear pore are mediated by nuclear transport receptors and are highly regulated. The nuclear pore complex is also used by several RNA viruses and almost all DNA viruses to access the host cell nucleoplasm for replication. Viruses hijack the nuclear pore complex, and nuclear transport receptors, to access the nucleoplasm where they replicate. In addition, the nuclear pore complex is used by the cell innate immune system, a network of signal transduction pathways that coordinates the first response to foreign invaders, including viruses and other pathogens. Several branches of this response depend on dynamic signaling events that involve the nuclear translocation of downstream signal transducers. Mounting evidence has shown that these signaling cascades, especially those steps that involve nucleocytoplasmic trafficking events, are targeted by viruses so that they can evade the innate immune system. This review summarizes how nuclear pore proteins and nuclear transport receptors contribute to the innate immune response and highlights how viruses manipulate this cellular machinery to favor infection. A comprehensive understanding of nuclear pore proteins in antiviral innate immunity will likely contribute to the development of new antiviral therapeutic strategies.
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Affiliation(s)
- Qingtang Shen
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Yifan E Wang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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Kim SJ, Cho NC, Han B, Kim K, Hahn YI, Kim KP, Suh YG, Choi BY, Na HK, Surh YJ. 15-Deoxy-Δ 12,14 -prostaglandin J 2 binds and inactivates STAT3 via covalent modification of cysteine 259 in H-Ras-transformed human breast epithelial cells. FEBS Lett 2021; 595:604-622. [PMID: 33452674 DOI: 10.1002/1873-3468.14040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 01/02/2023]
Abstract
Signal transducer and activator of transcription 3 (STAT3) has been considered as a potential target for development of anticancer therapeutics. Here, we report a novel mechanism by which the cyclopentenone prostaglandin, 15-deoxy-Δ12,14 -prostaglandin J2 (15d-PGJ2 ) functions as an allosteric inhibitor of STAT3. 15d-PGJ2 inhibits phosphorylation, dimerization, nuclear translocation, and transcriptional activity of STAT3 in H-Ras-transformed human mammary epithelial cells (MCF10A-Ras) through the Michael addition reaction at cysteine 259 of STAT3. Comparative studies with 15d-PGJ2 analogues reveal that both C12-C13 and C9-C10 double bonds conjugated to the carbonyl group in the cyclopentenone ring of 15d-PGJ2 are essential for STAT3 binding. Antiproliferative and pro-apoptotic activities of 15d-PGJ2 in MCF10A-Ras cells are attributable to covalent modification of STAT3 on Cys259, and mimic the effects induced by mutation of this amino acid.
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Affiliation(s)
- Su-Jung Kim
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Korea
| | - Nam-Chul Cho
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Korea
| | - Bitnara Han
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University, Yongin, Korea
| | - Kyeojin Kim
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Korea
| | - Young-Il Hahn
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University, Yongin, Korea.,Department of Biomedical Science and Technology, Kyung Hee Medical Science Research Institute, Kyung Hee University, Seoul, Korea
| | - Young Ger Suh
- College of Pharmacy, CHA University, Gyeonggi-do, Korea
| | - Bu Young Choi
- Department of Pharmaceutical Science and Engineering, School of Convergence Bioscience and Technology, Seowon University, Chungbuk, Korea
| | - Hye-Kyung Na
- Department of Food Science and Biotechnology, College of Knowledge Based Services Engineering, Sungshin Women's University, Seoul, Korea
| | - Young-Joon Surh
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Korea.,Cancer Research Institute, Seoul National University, Korea
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11
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Moore R, Vogt K, Acosta-Martin AE, Shire P, Zeidler M, Smythe E. Integration of JAK/STAT receptor-ligand trafficking, signalling and gene expression in Drosophila melanogaster cells. J Cell Sci 2020; 133:jcs246199. [PMID: 32917740 DOI: 10.1242/jcs.246199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 09/02/2020] [Indexed: 12/18/2022] Open
Abstract
The JAK/STAT pathway is an essential signalling cascade required for multiple processes during development and for adult homeostasis. A key question in understanding this pathway is how it is regulated in different cell contexts. Here, we have examined how endocytic processing contributes to signalling by the single cytokine receptor in Drosophila melanogaster cells, Domeless. We identify an evolutionarily conserved di-leucine (di-Leu) motif that is required for Domeless internalisation and show that endocytosis is required for activation of a subset of Domeless targets. Our data indicate that endocytosis both qualitatively and quantitatively regulates Domeless signalling. STAT92E, the single STAT transcription factor in Drosophila, appears to be the target of endocytic regulation, and our studies show that phosphorylation of STAT92E on Tyr704, although necessary, is not always sufficient for target transcription. Finally, we identify a conserved residue, Thr702, which is essential for Tyr704 phosphorylation. Taken together, our findings identify previously unknown aspects of JAK/STAT pathway regulation likely to play key roles in the spatial and temporal regulation of signalling in vivo.
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Affiliation(s)
- Rachel Moore
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Katja Vogt
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Adelina E Acosta-Martin
- biOMICS Facility, Faculty of Science Mass Spectrometry Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Patrick Shire
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Martin Zeidler
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Elizabeth Smythe
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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12
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Ramadurgum P, Hulleman JD. Protocol for Designing Small-Molecule-Regulated Destabilizing Domains for In Vitro Use. STAR Protoc 2020; 1. [PMID: 32995752 PMCID: PMC7521665 DOI: 10.1016/j.xpro.2020.100069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The use of destabilizing domains (DDs) to conditionally control the abundance of a protein of interest (POI) through a small-molecule stabilizer has gained increasing traction both in vitro and in vivo. Yet there are specific considerations for the development and accurate control of user-defined POIs via DDs, as well as the identification of novel (and potentially synergistic) small-molecule stabilizers. Here, we describe a platform for achieving these goals. For complete details on the use and execution of this protocol, please refer to Ramadurgum et al. (2020). Conditional protein of interest (POI) regulation by destabilizing domain (DD) fusion Focus on the utility of the E. coli dihydrofolate reductase (ecDHFR) DD Dynamically define the levels of a POI through diverse ligands Simultaneous DD stabilization and control of synergistic cellular signaling pathways
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Affiliation(s)
- Prerana Ramadurgum
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - John D Hulleman
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Technical Contact.,Lead Contact
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13
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Kagawa Y, Umaru BA, Shima H, Ito R, Zama R, Islam A, Kanno SI, Yasui A, Sato S, Jozaki K, Shil SK, Miyazaki H, Kobayashi S, Yamamoto Y, Kogo H, Shimamoto-Mitsuyama C, Sugawara A, Sugino N, Kanamori M, Tominaga T, Yoshikawa T, Fukunaga K, Igarashi K, Owada Y. FABP7 Regulates Acetyl-CoA Metabolism Through the Interaction with ACLY in the Nucleus of Astrocytes. Mol Neurobiol 2020; 57:4891-4910. [PMID: 32812201 PMCID: PMC7541391 DOI: 10.1007/s12035-020-02057-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/07/2020] [Indexed: 01/17/2023]
Abstract
Fatty acid binding protein 7 (FABP7) is an intracellular fatty acid chaperon that is highly expressed in astrocytes, oligodendrocyte-precursor cells, and malignant glioma. Previously, we reported that FABP7 regulates the response to extracellular stimuli by controlling the expression of caveolin-1, an important component of lipid raft. Here, we explored the detailed mechanisms underlying FABP7 regulation of caveolin-1 expression using primary cultured FABP7-KO astrocytes as a model of loss of function and NIH-3T3 cells as a model of gain of function. We discovered that FABP7 interacts with ATP-citrate lyase (ACLY) and is important for acetyl-CoA metabolism in the nucleus. This interaction leads to epigenetic regulation of several genes, including caveolin-1. Our novel findings suggest that FABP7-ACLY modulation of nuclear acetyl-CoA has more influence on histone acetylation than cytoplasmic acetyl-CoA. The changes to histone structure may modify caveolae-related cell activity in astrocytes and tumors, including malignant glioma.
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Affiliation(s)
- Yoshiteru Kagawa
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
| | - Banlanjo Abdulaziz Umaru
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ryo Ito
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ryo Zama
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ariful Islam
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Shin-Ichiro Kanno
- Division of Dynamic Proteome in Aging and Cancer, Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, 980-8575, Japan
| | - Akira Yasui
- Division of Dynamic Proteome in Aging and Cancer, Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, 980-8575, Japan
| | - Shun Sato
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube, 755-0046, Japan
| | - Kosuke Jozaki
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube, 755-0046, Japan
| | - Subrata Kumar Shil
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Hirofumi Miyazaki
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Shuhei Kobayashi
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Yui Yamamoto
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Hiroshi Kogo
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan
| | | | - Akira Sugawara
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Norihiro Sugino
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube, 755-0046, Japan
| | - Masayuki Kanamori
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, Wako, 351-0198, Japan
| | - Kohji Fukunaga
- Department of Pharmacology, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, 980-8578, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Yuji Owada
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
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14
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Yang J, Kunimoto H, Katayama B, Zhao H, Shiromizu T, Wang L, Ozawa T, Tomonaga T, Tsuruta D, Nakajima K. Phospho-Ser727 triggers a multistep inactivation of STAT3 by rapid dissociation of pY705-SH2 through C-terminal tail modulation. Int Immunol 2020; 32:73-88. [PMID: 31555812 PMCID: PMC10689346 DOI: 10.1093/intimm/dxz061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 09/18/2019] [Indexed: 12/21/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) is involved in many biological processes, including immunity and cancer. STAT3 becomes phosphorylated at Tyr705 and Ser727 on IL-6 stimulation. Phospho-Tyr705 (pY705) stabilizes the STAT3 dimer with reciprocal interactions between pY705 and the SH2 of the other molecule and phospho-Ser727 (pS727) accelerates pY705 dephosphorylation. We study how pS727 regulates STAT3 in both structural and biological perspectives. Using STAT3 reconstituted in HepG2-stat3-knockout cells, we show that pS727, together with a handshake N-terminal domain (NTD) interaction, causes rapid inactivation of STAT3 for pY705 dephosphorylation and a chromosome region maintenance 1 (CRM1)-independent nuclear export, which is critical for faithful STAT3 response to the cellular signals. The various N-terminal tags, GFP-related Ruby and FLAG, rendered the export CRM1-dependent and especially FLAG-tag caused nuclear accumulation of STAT3, indicating the presence of conformational changes in inactivation. Impaired reactivation of STAT3 by S727A or FLAG-tag delayed or inhibited the IL-6-induced saa1 mRNA expression, respectively. The detailed analysis of the pY705-SH2 structure identified the C-terminal tail (CTT) from L706 to P715 as a key regulator of the CTT-CTT intermolecular and the CTT-SH2 intramolecular interactions that support pY705-SH2 association. The functional studies using multiple STAT3 mutants indicated that the degree of the two interactions determines the stability of pY705-SH2 interaction. Importantly, Pro715 was critical for the pS727's destabilizing activity and the known phosphorylation and acetylation at the CTT structurally inhibited the pY705-SH2 interaction. Thus, pS727 triggers pY705-SH2 dissociation by weakening the supportive interactions likely through CTT modulation, inducing rapid cycles of STAT3 activation-inactivation for proper function of STAT3.
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Affiliation(s)
- Junhao Yang
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Hiroyuki Kunimoto
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Bumpei Katayama
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Hong Zhao
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Takashi Shiromizu
- Laboratory of Proteome Research, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka, Japan
| | - Lingyu Wang
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Toshiyuki Ozawa
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Takeshi Tomonaga
- Laboratory of Proteome Research, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka, Japan
| | - Daisuke Tsuruta
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Koichi Nakajima
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
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15
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Ernst S, Müller-Newen G. Nucleocytoplasmic Shuttling of STATs. A Target for Intervention? Cancers (Basel) 2019; 11:cancers11111815. [PMID: 31752278 PMCID: PMC6895884 DOI: 10.3390/cancers11111815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 12/12/2022] Open
Abstract
Signal transducer and activator of transcription (STAT) proteins are transcription factors that in the latent state are located predominantly in the cytoplasm. Activation of STATs through phosphorylation of a single tyrosine residue results in nuclear translocation. The requirement of tyrosine phosphorylation for nuclear accumulation is shared by all STAT family members but mechanisms of nuclear translocation vary between different STATs. These differences offer opportunities for specific intervention. To achieve this, the molecular mechanisms of nucleocytoplasmic shuttling of STATs need to be understood in more detail. In this review we will give an overview on the various aspects of nucleocytoplasmic shuttling of latent and activated STATs with a special focus on STAT3 and STAT5. Potential targets for cancer treatment will be identified and discussed.
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Affiliation(s)
- Sabrina Ernst
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, 52074 Aachen, Germany;
- Confocal Microscopy Facility, Interdisciplinary Center for Clinical Research IZKF, RWTH Aachen University, 52074 Aachen, Germany
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, 52074 Aachen, Germany;
- Correspondence:
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16
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Ramakrishnan M, Zhou MB, Pan CF, Hänninen H, Tang DQ, Vinod KK. Nuclear export signal (NES) of transposases affects the transposition activity of mariner-like elements Ppmar1 and Ppmar2 of moso bamboo. Mob DNA 2019; 10:35. [PMID: 31452694 PMCID: PMC6699137 DOI: 10.1186/s13100-019-0179-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 08/14/2019] [Indexed: 11/10/2022] Open
Abstract
Ppmar1 and Ppmar2 are two active mariner-like elements (MLEs) cloned from moso bamboo (Phyllostachys edulis (Carrière) J. Houz) genome possessing transposases that harbour nuclear export signal (NES) domain, but not any nuclear localization signal (NLS) domain. To understand the functions of NES in transposon activity, we have conducted two experiments, fluorescence and excision frequency assays in the yeast system. For this, by site-directed mutagenesis, three NES mutants were developed from each of the MLE. In the fluorescence assay, the mutants, NES-1, 2 and 3 along with the wild types (NES-0) were fused with fluorescent proteins, enhanced yellow fluorescent protein (EYFP) and enhanced cyan fluorescent protein (ECFP) were co-transformed into yeast system. To differentiate protein localisation under the NES influence, ECFP alone was fused to wild and mutant NES domains either on N- or C-terminal and not to EYFP. Fluorescence assay revealed that blue fluorescence of ECFP was more intense than the red fluorescence of the EYFP in the yeast cell matrix. Further, ECFP had a wider localisation in the cellular matrix, but EYFP was largely located in the nucleus. The NES-1 domain was related to the comparatively high spread of ECFP, while NES-2 and NES-3 indicated a low spread, implying that NES activity on nuclear export increased when the NES is made leucine-rich, while the signalling activity was reduced when the leucine content was lowered in the NES domain. In the transposon excision assay, the mutant and wild type NES of both the Ppmar elements were integrated into an Ade2 vector, and within the Ade2 gene. Co-transformation of the vector together with non-autonomous Ppmar transposons and NES-lacking transposases was used to assess the differential excision frequencies of the mutants NES domains. In both the MLEs, NES-1 had the highest excision suppression, which was less than half of the excision frequency of the wild type. NES-2 and NES-3 elements showed, up to three times increase in transposon excision than the wild types. The results suggested that NES is an important regulator of nuclear export of transposase in Ppmar elements and the mutation of the NES domains can either increase or decrease the export signalling. We speculate that in moso bamboo, NESs regulates the transposition activity of MLEs to maintain the genome integrity.
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Affiliation(s)
- Muthusamy Ramakrishnan
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
| | - Ming-Bing Zhou
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
- Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-efficiency Utilization, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
| | - Chun-Fang Pan
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
| | - Heikki Hänninen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
| | - Ding-Qin Tang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, Hangzhou, 311300 Zhejiang Province People’s Republic of China
| | - Kunnummal Kurungara Vinod
- Division of Genetics, Rice Breeding and Genetics Research Centre, ICAR-Indian Agricultural Research Institute, Aduthurai, Tamil Nadu 612101 India
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17
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Abstract
Healthy tissues of the body express relatively low basal levels of interferons. However, following detection of microbial invasion by sentinel receptors, a cascade of events initiates leading to the transcriptional induction of interferon genes. Interferons are secreted and act primarily as paracrine cytokines to bind neighboring cell surface receptors. Binding to interferon receptors activates a signal pathway to the nucleus inducing a set of interferon-stimulated genes. The biological activity of these genes confers the unique antiviral and innate immune response of interferons. The rapid induction of interferons is critical to survival, and equally critical is the recovery from this defensive state. Either an aberrant response to infection or an inherited genetic disorder that leads to sustained or increased interferon levels can tip the balance towards pathogenesis.
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Affiliation(s)
- Nancy C Reich
- Stony Brook University, Dept Molecular Genetics & Microbiology, 11796 Stony Brook, NY, USA.
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18
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Chiang HS, Liu HM. The Molecular Basis of Viral Inhibition of IRF- and STAT-Dependent Immune Responses. Front Immunol 2019; 9:3086. [PMID: 30671058 PMCID: PMC6332930 DOI: 10.3389/fimmu.2018.03086] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/13/2018] [Indexed: 01/07/2023] Open
Abstract
The antiviral innate immunity is the first line of host defense against virus infections. In mammalian cells, viral infections initiate the expression of interferons (IFNs) in the host that in turn activate an antiviral defense program to restrict viral replications by induction of IFN stimulated genes (ISGs), which are largely regulated by the IFN-regulatory factor (IRF) family and signal transducer and activator of transcription (STAT) family transcription factors. The mechanisms of action of IRFs and STATs involve several post-translational modifications, complex formation, and nuclear translocation of these transcription factors. However, many viruses, including human immunodeficiency virus (HIV), Zika virus (ZIKV), and herpes simplex virus (HSV), have evolved strategies to evade host defense, including alteration in IRF and STAT post-translational modifications, disturbing the formation and nuclear translocation of the transcription complexes as well as proteolysis/degradation of IRFs and STATs. In this review, we discuss and summarize the molecular mechanisms by which how viral components may target IRFs and STATs to antagonize the establishment of antiviral host defense. The underlying host-viral interactions determine the outcome of viral infection. Gaining mechanistic insight into these processes will be crucial in understanding how viral replication can be more effectively controlled and in developing approaches to improve virus infection outcomes.
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Affiliation(s)
- Hao-Sen Chiang
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University, Taipei, Taiwan
| | - Helene Minyi Liu
- Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
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19
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The Methyltransferase-Like Domain of Chikungunya Virus nsP2 Inhibits the Interferon Response by Promoting the Nuclear Export of STAT1. J Virol 2018; 92:JVI.01008-18. [PMID: 29925658 DOI: 10.1128/jvi.01008-18] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 06/14/2018] [Indexed: 12/15/2022] Open
Abstract
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that has evolved effective mechanisms to counteract the type I interferon (IFN) response. Upon recognition of the virus, cells secrete IFNs, which signal through transmembrane receptors (IFNAR) to phosphorylate STAT proteins (pSTAT). pSTAT dimers are transported into the nucleus by importin-α5 and activate the transcription of IFN-stimulated genes (ISGs), increasing cellular resistance to infection. Subsequently, STAT proteins are shuttled back into the cytoplasm by the exportin CRM1. CHIKV nonstructural protein 2 (nsP2) reduces ISG expression by inhibiting general host cell transcription and by specifically reducing the levels of nuclear pSTAT1 via an unknown mechanism. To systematically examine where nsP2 acts within the JAK/STAT signaling cascade, we used two well-characterized mutants of nsP2, P718S and KR649AA. Both mutations abrogate nsP2's ability to shut off host transcription, but only the KR649AA mutant localizes exclusively to the cytoplasm and no longer specifically inhibits JAK/STAT signaling. These mutant nsP2 proteins did not differentially affect IFNAR expression levels or STAT1 phosphorylation in response to IFNs. Coimmunoprecipitation experiments showed that in the presence of nsP2, STAT1 still effectively bound importin-α5. Chemically blocking CRM1-mediated nuclear export in the presence of nsP2 additionally showed that nuclear translocation of STAT1 is not affected by nsP2. nsP2 putatively has five domains. Redirecting the nsP2 KR649AA mutant or just nsP2's C-terminal methyltransferase-like domain into the nucleus strongly reduced nuclear pSTAT in response to IFN stimulation. This demonstrates that the C-terminal domain of nuclear nsP2 specifically inhibits the IFN response by promoting the nuclear export of STAT1.IMPORTANCE Chikungunya virus is an emerging pathogen associated with large outbreaks on the African, Asian, European, and both American continents. In most patients, infection results in high fever, rash, and incapacitating (chronic) arthralgia. CHIKV effectively inhibits the first line of defense, the innate immune response. As a result, stimulation of the innate immune response with interferons (IFNs) is ineffective as a treatment for CHIKV disease. The IFN response requires an intact downstream signaling cascade called the JAK/STAT signaling pathway, which is effectively inhibited by CHIKV nonstructural protein 2 (nsP2) via an unknown mechanism. The research described here specifies where in the JAK/STAT signaling cascade the IFN response is inhibited and which protein domain of nsP2 is responsible for IFN inhibition. The results illuminate new aspects of antiviral defense and CHIKV counterdefense strategies and will direct the search for novel antiviral compounds.
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20
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Korwek Z, Tudelska K, Nałęcz-Jawecki P, Czerkies M, Prus W, Markiewicz J, Kochańczyk M, Lipniacki T. Importins promote high-frequency NF-κB oscillations increasing information channel capacity. Biol Direct 2016; 11:61. [PMID: 27835978 PMCID: PMC5106790 DOI: 10.1186/s13062-016-0164-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/29/2016] [Indexed: 12/18/2022] Open
Abstract
Background Importins and exportins influence gene expression by enabling nucleocytoplasmic shuttling of transcription factors. A key transcription factor of innate immunity, NF-κB, is sequestered in the cytoplasm by its inhibitor, IκBα, which masks nuclear localization sequence of NF-κB. In response to TNFα or LPS, IκBα is degraded, which allows importins to bind NF-κB and shepherd it across nuclear pores. NF-κB nuclear activity is terminated when newly synthesized IκBα enters the nucleus, binds NF-κB and exportin which directs the complex to the cytoplasm. Although importins/exportins are known to regulate spatiotemporal kinetics of NF-κB and other transcription factors governing innate immunity, the mechanistic details of these interactions have not been elucidated and mathematically modelled. Results Based on our quantitative experimental data, we pursue NF-κB system modelling by explicitly including NF-κB–importin and IκBα–exportin binding to show that the competition between importins and IκBα enables NF-κB nuclear translocation despite high levels of IκBα. These interactions reduce the effective relaxation time and allow the NF-κB regulatory pathway to respond to recurrent TNFα pulses of 45-min period, which is about twice shorter than the characteristic period of NF-κB oscillations. By stochastic simulations of model dynamics we demonstrate that randomly appearing, short TNFα pulses can be converted to essentially digital pulses of NF-κB activity, provided that intervals between input pulses are not shorter than 1 h. Conclusions By including interactions involving importin-α and exportin we bring the modelling of spatiotemporal kinetics of transcription factors to a more mechanistic level. Basing on the analysis of the pursued model we estimated the information transmission rate of the NF-κB pathway as 1 bit per hour. Reviewers This article was reviewed by Marek Kimmel, James Faeder and William Hlavacek. Electronic supplementary material The online version of this article (doi:10.1186/s13062-016-0164-z) contains supplementary material.
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Affiliation(s)
- Zbigniew Korwek
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Karolina Tudelska
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Paweł Nałęcz-Jawecki
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Maciej Czerkies
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Wiktor Prus
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna Markiewicz
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Marek Kochańczyk
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz Lipniacki
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland.
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21
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Abstract
Autophagy is an evolutionarily conserved process in eukaryotes that eliminates harmful components and maintains cellular homeostasis in response to a series of extracellular insults. However, these insults may trigger the downstream signaling of another prominent stress responsive pathway, the STAT3 signaling pathway, which has been implicated in multiple aspects of the autophagic process. Recent reports further indicate that different subcellular localization patterns of STAT3 affect autophagy in various ways. For example, nuclear STAT3 fine-tunes autophagy via the transcriptional regulation of several autophagy-related genes such as BCL2 family members, BECN1, PIK3C3, CTSB, CTSL, PIK3R1, HIF1A, BNIP3, and microRNAs with targets of autophagy modulators. Cytoplasmic STAT3 constitutively inhibits autophagy by sequestering EIF2AK2 as well as by interacting with other autophagy-related signaling molecules such as FOXO1 and FOXO3. Additionally, the mitochondrial translocation of STAT3 suppresses autophagy induced by oxidative stress and may effectively preserve mitochondria from being degraded by mitophagy. Understanding the role of STAT3 signaling in the regulation of autophagy may provide insight into the classic autophagy model and also into cancer therapy, especially for the emerging targeted therapy, because a series of targeted agents execute antitumor activities via blocking STAT3 signaling, which inevitably affects the autophagy pathway. Here, we review several of the representative studies and the current understanding in this particular field.
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Key Words
- ALK, anaplastic lymphoma receptor tyrosine kinase
- ATF4, activating transcription factor 4
- BNIP3, BCL2/adenovirus E1B 19kDa interacting protein 3
- CNTF, ciliary neurotrophic factor
- COX8, cytochrome c oxidase subunit VIII
- CTSB, cathepsin B
- CTSL, cathepsin L
- CYCS, cytochrome c, somatic
- ConA, concanavalin A
- CuB, cucurbitacin B
- EGF, epidermal growth factor
- EIF2A, eukaryotic initiation factor 2A, 65kDa
- EIF2AK2, eukaryotic translation initiation factor 2-α kinase 2
- ER, endoplasmic reticulum
- ETC, electron transport chain
- FOXO1/3, forkhead box O1/3
- HDAC3, histone deacetylase 3
- HIF1A, hypoxia inducible factor 1, α subunit (basic helix-loop-helix transcription factor)
- IL6, interleukin 6
- IMM, inner mitochondrial membrane
- KDR, kinase insert domain receptor
- LMP, lysosomal membrane permeabilization
- MAP1LC3A, microtubule-associated protein 1 light chain 3 α
- MAPK1, mitogen-activated protein kinase 1
- MLS, mitochondrial localization sequence
- MMP14, matrix metallopeptidase 14 (membrane-inserted)
- NDUFA13, NADH dehydrogenase (ubiquinone) 1 α subcomplex, 13
- NES, nuclear export signal
- NFKB1, nuclear factor of kappa light polypeptide gene enhancer in B-cells 1
- NLS, nuclear localization signal
- PDGFRB, platelet-derived growth factor receptor, β polypeptide
- PRKAA2, protein kinase, AMP-activated, α 2 catalytic subunit
- PTPN11, protein tyrosine phosphatase, non-receptor type 11
- PTPN2, protein tyrosine phosphatase, non-receptor type 2
- PTPN6, protein tyrosine phosphatase, non-receptor type 6
- ROS, reactive oxygen species
- RTK, receptor tyrosine kinases
- SH2, src homology 2
- STAT3
- STAT3, signal transducer and activator of transcription 3 (acute-phase response factor)
- VHL, von Hippel-Lindau tumor suppressor, E3 ubiquitin protein ligase
- XPO1, exportin 1
- autophagy
- cancer
- miRNA, microRNA
- mitoSTAT3, mitochondrial STAT3
- mitophagy
- receptor tyrosine kinases
- targeted therapy
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Affiliation(s)
- Liangkun You
- a Department of Medical Oncology; Zhejiang University ; Hangzhou , Zhejiang , China
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22
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Majoros A, Platanitis E, Szappanos D, Cheon H, Vogl C, Shukla P, Stark GR, Sexl V, Schreiber R, Schindler C, Müller M, Decker T. Response to interferons and antibacterial innate immunity in the absence of tyrosine-phosphorylated STAT1. EMBO Rep 2016; 17:367-82. [PMID: 26882544 PMCID: PMC4772975 DOI: 10.15252/embr.201540726] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 01/13/2016] [Indexed: 01/12/2023] Open
Abstract
Signal transducer and activator of transcription 1 (STAT1) plays a pivotal role in the innate immune system by directing the transcriptional response to interferons (IFNs). STAT1 is activated by Janus kinase (JAK)‐mediated phosphorylation of Y701. To determine whether STAT1 contributes to cellular responses without this phosphorylation event, we generated mice with Y701 mutated to a phenylalanine (Stat1Y701F). We show that heterozygous mice do not exhibit a dominant‐negative phenotype. Homozygous Stat1Y701F mice show a profound reduction in Stat1 expression, highlighting an important role for basal IFN‐dependent signaling. The rapid transcriptional response to type I IFN (IFN‐I) and type II IFN (IFNγ) was absent in Stat1Y701F cells. Intriguingly, STAT1Y701F suppresses the delayed expression of IFN‐I‐stimulated genes (ISG) observed in Stat1−/− cells, mediated by the STAT2/IRF9 complex. Thus, Stat1Y701F macrophages are more susceptible to Legionella pneumophila infection than Stat1−/− macrophages. Listeria monocytogenes grew less robustly in Stat1Y701F macrophages and mice compared to Stat1−/− counterparts, but STAT1Y701F is not sufficient to rescue the animals. Our studies are consistent with a potential contribution of Y701‐unphosphorylated STAT1 to innate antibacterial immunity.
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Affiliation(s)
- Andrea Majoros
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | | | - Daniel Szappanos
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - HyeonJoo Cheon
- Department of Molecular Genetics and Proteomics Core, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Claus Vogl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Priyank Shukla
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - George R Stark
- Department of Molecular Genetics and Proteomics Core, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Veronika Sexl
- Department for Biomedical Sciences, Institute of Pharmacology and Toxicology University of Veterinary Medicine Vienna, Vienna, Austria
| | - Robert Schreiber
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Christian Schindler
- Departments of Microbiology & Immunology and Medicine, Columbia University, New York, NY, USA
| | - Mathias Müller
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Thomas Decker
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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Conway AE, Haldeman JM, Wechsler DS, Lavau CP. A critical role for CRM1 in regulating HOXA gene transcription in CALM-AF10 leukemias. Leukemia 2015; 29:423-32. [PMID: 25027513 PMCID: PMC4297268 DOI: 10.1038/leu.2014.221] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 06/15/2014] [Accepted: 07/08/2014] [Indexed: 01/01/2023]
Abstract
The leukemogenic CALM-AF10 fusion protein is found in patients with immature acute myeloid and T-lymphoid malignancies. CALM-AF10 leukemias display abnormal H3K79 methylation and increased HOXA cluster gene transcription. Elevated expression of HOXA genes is critical for leukemia maintenance and progression; however, the precise mechanism by which CALM-AF10 alters HOXA gene expression is unclear. We previously determined that CALM contains a CRM1-dependent nuclear export signal (NES), which is both necessary and sufficient for CALM-AF10-mediated leukemogenesis. Here, we find that interaction of CALM-AF10 with the nuclear export receptor CRM1 is necessary for activating HOXA gene expression. We show that CRM1 localizes to HOXA loci where it recruits CALM-AF10, leading to transcriptional and epigenetic activation of HOXA genes. Genetic and pharmacological inhibition of the CALM-CRM1 interaction prevents CALM-AF10 enrichment at HOXA chromatin, resulting in immediate loss of transcription. These results provide a comprehensive mechanism by which the CALM-AF10 translocation activates the critical HOXA cluster genes. Furthermore, this report identifies a novel function of CRM1: the ability to bind chromatin and recruit the NES-containing CALM-AF10 transcription factor.
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Affiliation(s)
- Amanda E. Conway
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Jonathan M. Haldeman
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Daniel S. Wechsler
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Catherine P. Lavau
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Duke University Medical Center, Durham, NC 27710, USA
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24
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Sobhkhez M, Skjesol A, Thomassen E, Tollersrud LG, Iliev DB, Sun B, Robertsen B, Jørgensen JB. Structural and functional characterization of salmon STAT1, STAT2 and IRF9 homologs sheds light on interferon signaling in teleosts. FEBS Open Bio 2014; 4:858-71. [PMID: 25379383 PMCID: PMC4215117 DOI: 10.1016/j.fob.2014.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/24/2014] [Accepted: 09/26/2014] [Indexed: 01/10/2023] Open
Abstract
Mammalian IRF9 and STAT2, together with STAT1, form the ISGF3 transcription factor complex, which is critical for type I interferon (IFN)-induced signaling, while IFNγ stimulation is mediated by homodimeric STAT1 protein. Teleost fish are known to possess most JAK and STAT family members, however, description of their functional activity in lower vertebrates is still scarce. In the present study we have identified two different STAT2 homologs and one IRF9 homolog from Atlantic salmon (Salmo salar). Both proteins have domain-like structures with functional motifs that are similar to higher vertebrates, suggesting that they are orthologs to mammalian STAT2 and IRF9. The two identified salmon STAT2s, named STAT2a and STAT2b, showed high sequence identity but were divergent in their transactivation domain (TAD). Like STAT1, ectopically expressed STAT2a and b were shown to be tyrosine phosphorylated by type I IFNs and, interestingly, also by IFNγ. Microscopy analyses demonstrated that STAT2 co-localized with STAT1a in the cytoplasm of unstimulated cells, while IFNa1 and IFNγ stimulation seemed to favor their nuclear localization. Overexpression of STAT2a or STAT2b together with STAT1a activated a GAS-containing reporter gene construct in IFNγ-stimulated cells. The highest induction of GAS promoter activation was found in IFNγ-stimulated cells transfected with IRF9 alone. Taken together, these data suggest that salmon STAT2 and IRF9 may have a role in IFNγ-induced signaling and promote the expression of GAS-driven genes in bony fish. Since mammalian STAT2 is primarily an ISGF3 component and not involved in IFNγ signaling, our finding features a novel role for STAT2 in fish.
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Affiliation(s)
- Mehrdad Sobhkhez
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Astrid Skjesol
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Ernst Thomassen
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Linn Greiner Tollersrud
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Dimitar B Iliev
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Baojian Sun
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Børre Robertsen
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Jorunn B Jørgensen
- The Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
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25
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Holloway G, Dang VT, Jans DA, Coulson BS. Rotavirus inhibits IFN-induced STAT nuclear translocation by a mechanism that acts after STAT binding to importin-α. J Gen Virol 2014; 95:1723-1733. [DOI: 10.1099/vir.0.064063-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The importance of innate immunity to rotaviruses is exemplified by the range of strategies evolved by rotaviruses to interfere with the IFN response. We showed previously that rotaviruses block gene expression induced by type I and II IFNs, through a mechanism allowing activation of signal transducer and activator of transcription (STAT) 1 and STAT2 but preventing their nuclear accumulation. This normally occurs through activated STAT1/2 dimerization, enabling an interaction with importin α5 that mediates transport into the nucleus. In rotavirus-infected cells, STAT1/2 inhibition may limit the antiviral actions of IFN produced early in infection. Here we further analysed the block to STAT1/2 nuclear accumulation, showing that activated STAT1 accumulates in the cytoplasm in rotavirus-infected cells. STAT1/2 nuclear accumulation was inhibited by rotavirus even in the presence of the nuclear export inhibitor Leptomycin B, demonstrating that enhanced nuclear export is not involved in STAT1/2 cytoplasmic retention. The ability to inhibit STAT nuclear translocation was completely conserved amongst the group A rotaviruses tested, including a divergent avian strain. Analysis of mutant rotaviruses indicated that residues after amino acid 47 of NSP1 are dispensable for STAT inhibition. Furthermore, expression of any of the 12 Rhesus monkey rotavirus proteins did not inhibit IFN-stimulated STAT1 nuclear translocation. Finally, co-immunoprecipitation experiments from transfected epithelial cells showed that STAT1/2 binds importin α5 normally following rotavirus infection. These findings demonstrate that rotavirus probably employs a novel strategy to inhibit IFN-induced STAT signalling, which acts after STAT activation and binding to the nuclear import machinery.
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Affiliation(s)
- Gavan Holloway
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
| | - Vi T. Dang
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
| | - David A. Jans
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Barbara S. Coulson
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
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26
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Takeda A, Yaseen NR. Nucleoporins and nucleocytoplasmic transport in hematologic malignancies. Semin Cancer Biol 2014; 27:3-10. [PMID: 24657637 DOI: 10.1016/j.semcancer.2014.02.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/19/2022]
Abstract
Hematologic malignancies are often associated with chromosomal rearrangements that lead to the expression of chimeric fusion proteins. Rearrangements of the genes encoding two nucleoporins, NUP98 and NUP214, have been implicated in the pathogenesis of several types of hematologic malignancies, particularly acute myeloid leukemia. NUP98 rearrangements result in fusion of an N-terminal portion of NUP98 to one of numerous proteins. These rearrangements often follow treatment with topoisomerase II inhibitors and tend to occur in younger patients. They have been shown to induce leukemia in mice and to enhance proliferation and disrupt differentiation in primary human hematopoietic precursors. NUP214 has only a few fusion partners. DEK-NUP214 is the most common NUP214 fusion in AML; it tends to occur in younger patients and is usually associated with FLT3 internal tandem duplications. The leukemogenic activity of NUP214 fusions is less well characterized. Normal nucleoporins, including NUP98 and NUP214, have important functions in nucleocytoplasmic transport, transcription, and mitosis. These functions and their disruptions by oncogenic nucleoporin fusions are discussed.
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Affiliation(s)
- Akiko Takeda
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
| | - Nabeel R Yaseen
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
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27
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Reich NC. STATs get their move on. JAKSTAT 2013; 2:e27080. [PMID: 24470978 PMCID: PMC3891633 DOI: 10.4161/jkst.27080] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/01/2013] [Accepted: 11/04/2013] [Indexed: 12/18/2022] Open
Abstract
Understanding the mechanisms that regulate dynamic localization of a protein within a cell can provide critical insight to its functional molecular interactions. Signal transducers and activators of transcription (STATs) play essential roles in development, proliferation, and immune defense. However the consequences of STAT hyperactivity can predispose to diseases including autoimmunity and cancer. To function as transcription factors STATs must gain access to the nucleus, and knowledge of the mechanisms that regulate STAT nuclear trafficking can provide a means to control STAT action. This review presents a synopsis of some of the studies that address the nuclear dynamics of the STAT proteins. Evidence suggests that not all STATs are the same. Nuclear import of STAT1 and STAT4 appears linked to their tyrosine phosphorylation and the formation of parallel dimers via reciprocal phosphotyrosine and Src homology 2 domain interactions. This dimer arrangement generates a conformational nuclear localization signal. STAT2 is imported continually to the nucleus in an unphosphorylated state due to its association with IRF9, but the dominant nuclear export signal of STAT2 shuttles the complex back to the cytoplasm. Following STAT2 tyrosine phosphorylation, it can form dimers with STAT1 to affect nuclear import as the trimeric complex (ISGF3). Distinctly, STAT3, STAT5, and STAT6 are continually imported to the nucleus independent of tyrosine phosphorylation. Mutational studies indicate the nuclear localization signals in these STATs require the conformational structure of their coiled-coil domains. Increases in STAT nuclear accumulation following cytokine stimulation appear coordinate with their ability to bind DNA.
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Affiliation(s)
- Nancy C Reich
- Department of Molecular Genetics and Microbiology; Stony Brook University; Stony Brook, NY USA
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28
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Tanaka S, Nakao K, Sekimoto T, Oka M, Yoneda Y. Cell density-dependent nuclear accumulation of ELK3 is involved in suppression of PAI-1 expression. Cell Struct Funct 2013; 38:145-54. [PMID: 23708702 DOI: 10.1247/csf.13007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cell-cell contact regulates the proliferation and differentiation of non-transformed cells, e.g., NIH/3T3 cells show growth arrest at high cell density. However, only a few reports described the dynamic behavior of transcription factors involved in this process. In this study, we showed that the mRNA levels of plasminogen activator inhibitor type 1 (PAI-1) decreased drastically at high cell density, and that ELK3, a member of the Ets transcription factor family, repressed PAI-1 expression. We also demonstrated that while ELK3 was distributed evenly throughout the cell at low cell density, it accumulated in the nucleus at high cell density, and that binding of DNA by ELK3 at the A domain facilitated its nuclear accumulation. Furthermore, we found that ETS1, a PAI-1 activator, occupied the ELK3-binding site within the PAI-1 promoter at low cell density, while it was released at high cell density. These results suggest that at high cell density, the switching of binding of transcription factors from ETS1 to ELK3 occurs at a specific binding site of the PAI-1 promoter, leading to the cell-density dependent suppression of PAI-1 expression.
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Affiliation(s)
- Shu Tanaka
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, Yamada-oka, Suita, Osaka, Japan
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29
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Qi YF, Huang YX, Wang HY, Zhang Y, Bao YL, Sun LG, Wu Y, Yu CL, Song ZB, Zheng LH, Sun Y, Wang GN, Li YX. Elucidating the crosstalk mechanism between IFN-gamma and IL-6 via mathematical modelling. BMC Bioinformatics 2013; 14:41. [PMID: 23384097 PMCID: PMC3599299 DOI: 10.1186/1471-2105-14-41] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 02/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background Interferon-gamma (IFN-gamma) and interleukin-6 (IL-6) are multifunctional cytokines that regulate immune responses, cell proliferation, and tumour development and progression, which frequently have functionally opposing roles. The cellular responses to both cytokines are activated via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. During the past 10 years, the crosstalk mechanism between the IFN-gamma and IL-6 pathways has been studied widely and several biological hypotheses have been proposed, but the kinetics and detailed crosstalk mechanism remain unclear. Results Using established mathematical models and new experimental observations of the crosstalk between the IFN-gamma and IL-6 pathways, we constructed a new crosstalk model that considers three possible crosstalk levels: (1) the competition between STAT1 and STAT3 for common receptor docking sites; (2) the mutual negative regulation between SOCS1 and SOCS3; and (3) the negative regulatory effects of the formation of STAT1/3 heterodimers. A number of simulations were tested to explore the consequences of cross-regulation between the two pathways. The simulation results agreed well with the experimental data, thereby demonstrating the effectiveness and correctness of the model. Conclusion In this study, we developed a crosstalk model of the IFN-gamma and IL-6 pathways to theoretically investigate their cross-regulation mechanism. The simulation experiments showed the importance of the three crosstalk levels between the two pathways. In particular, the unbalanced competition between STAT1 and STAT3 for IFNR and gp130 led to preferential activation of IFN-gamma and IL-6, while at the same time the formation of STAT1/3 heterodimers enhanced preferential signal transduction by sequestering a fraction of the activated STATs. The model provided a good explanation of the experimental observations and provided insights that may inform further research to facilitate a better understanding of the cross-regulation mechanism between the two pathways.
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Affiliation(s)
- Yun-feng Qi
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun 130024, China
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30
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Cimica V, Reich NC. Nuclear trafficking of STAT proteins visualized by live cell imaging. Methods Mol Biol 2013; 967:189-202. [PMID: 23296731 DOI: 10.1007/978-1-62703-242-1_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The ability to observe the dynamic localization of a protein in living cells can provide critical insight to its mode of action and functional molecular interactions. To this purpose, green fluorescent protein (GFP) has served as a powerful tool to tag STAT proteins for microscopic visualization. Live cell imaging with STAT-GFP proteins has contributed to our understanding of signal transduction and the complexities of nuclear transport of STAT proteins. In this report we summarize recent approaches that use GFP-based techniques with live cell imaging to study the mechanisms of STAT nuclear import and export: photoactivation, fluorescence recovery after photobleaching (FRAP), and fluorescence loss in photobleaching (FLIP).
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Affiliation(s)
- Velasco Cimica
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
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31
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Marwarha G, Ghribi O. Leptin signaling and Alzheimer's disease. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2012; 1:245-265. [PMID: 23383396 PMCID: PMC3560472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/09/2012] [Indexed: 06/01/2023]
Abstract
Leptin, an adipocytokine produced in the peripheral system as well as in the brain, is implicated in obesity, food intake, glucose homeostasis, and energy expenditure. Leptin expression levels and signaling pathways may also be linked to the pathophysiology of neurodegenerative diseases including Alzheimer's disease. Epidemiological studies have demonstrated that higher circulating leptin levels are associated with lower risk of dementia including Alzheimer's disease, and lower circulating levels of leptin have been reported in patients with Alzheimer's disease. Leptin receptors are highly expressed in the hippocampus, a brain area involved in learning and memory and severely affected during the course of Alzheimer's disease. In laboratory studies, several in vivo and in vitro studies have shown that leptin supplementation decreases amyloid-β (Aβ) production and tau phosphorylation, two major biochemical events that play a key role in the pathogenesis of Alzheimer's disease. In this review, we will review the structure of leptin, the type of receptors of leptin in the brain, the various biological functions attributed to this adipocytokine, the signaling pathways that govern leptin actions, and the potential role of leptin in the pathophysiology of Alzheimer's disease. Leptin exerts its functions by binding to the leptin receptor (ObR). This binding can involve several signaling pathways including JAK/STAT pathway, ERK pathway and the PI3K/Akt/mTOR Pathway. Modulation of these pathways leads to the regulation of a multitude of functions that define the intricate involvement of leptin in various physiological tasks. In this review, we will specifically relate the potential involvement of leptin signaling in Alzheimer's disease based on work published by several laboratories including ours. All this work points to leptin as a possible target for developing supplementation therapies for reducing the progression of Alzheimer's disease.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences Grand Forks, North Dakota, 58202
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32
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Izumi Y, Li J, Villers C, Hashimoto K, Burg MB, Ferraris JD. Mutations that reduce its specific DNA binding inhibit high NaCl-induced nuclear localization of the osmoprotective transcription factor NFAT5. Am J Physiol Cell Physiol 2012; 303:C1061-9. [PMID: 22992674 PMCID: PMC3492838 DOI: 10.1152/ajpcell.00265.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/10/2012] [Indexed: 11/22/2022]
Abstract
The transcription factor nuclear factor of activated T cell 5 (NFAT5) is activated by the stress of hypertonicity (e.g., high NaCl). Increased expression of NFAT5 target genes causes accumulation of protective organic osmolytes and heat shock proteins. Under normotonic conditions (∼300 mosmol/kgH(2)O), NFAT5 is distributed between the nucleus and cytoplasm, hypertonicity causes it to translocate into the nucleus, and hypotonicity causes it to translocate into the cytoplasm. The mechanism of translocation is complex and not completely understood. NFAT5-T298 is a known contact site of NFAT5 with its specific DNA element [osmotic response element (ORE)]. In the present study, we find that mutation of NFAT5-T298 to alanine or aspartic acid not only reduces binding of NFAT5 to OREs (EMSA) but also proportionately reduces high NaCl-induced nuclear translocation of NFAT5. Combined mutation of other NFAT5 DNA contact sites (R293A/E299A/R302A) also greatly reduces both specific DNA binding and nuclear localization of NFAT5. NFAT5-T298 is a potential phosphorylation site, but, using protein mass spectrometry, we do not find phosphorylation at NFAT5-T298. Further, decreased high NaCl-induced nuclear localization of NFAT5 mutated at T298 does not involve previously known regulatory mechanisms, including hypotonicity-induced export of NFAT5, regulated by phosphorylation of NFAT5-S155, XPO1 (CRM1/exportin1)-mediated export of NFAT5 from the nucleus, or hypertonicity-induced elevation of NUP88, which enhances nuclear localization of NFAT5. We conclude that specific DNA binding of NFAT5 contributes to its nuclear localization, by mechanisms, as yet undetermined, but independent of ones previously described to regulate NFAT5 distribution.
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Affiliation(s)
- Yuichiro Izumi
- Systems Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
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Boisson-Dupuis S, Kong XF, Okada S, Cypowyj S, Puel A, Abel L, Casanova JL. Inborn errors of human STAT1: allelic heterogeneity governs the diversity of immunological and infectious phenotypes. Curr Opin Immunol 2012; 24:364-78. [PMID: 22651901 PMCID: PMC3477860 DOI: 10.1016/j.coi.2012.04.011] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Accepted: 04/30/2012] [Indexed: 01/04/2023]
Abstract
The genetic dissection of various human infectious diseases has led to the definition of inborn errors of human STAT1 immunity of four types, including (i) autosomal recessive (AR) complete STAT1 deficiency, (ii) AR partial STAT1 deficiency, (iii) autosomal dominant (AD) STAT1 deficiency, and (iv) AD gain of STAT1 activity. The two types of AR STAT1 defect give rise to a broad infectious phenotype with susceptibility to intramacrophagic bacteria (mostly mycobacteria) and viruses (herpes viruses at least), due principally to the impairment of IFN-γ-mediated and IFN-α/β-mediated immunity, respectively. Clinical outcome depends on the extent to which the STAT1 defect decreases responsiveness to these cytokines. AD STAT1 deficiency selectively predisposes individuals to mycobacterial disease, owing to the impairment of IFN-γ-mediated immunity, as IFN-α/β-mediated immunity is maintained. Finally, AD gain of STAT1 activity is associated with autoimmunity, probably owing to an enhancement of IFN-α/β-mediated immunity. More surprisingly, it is also associated with chronic mucocutaneous candidiasis, through as yet undetermined mechanisms involving an inhibition of the development of IL-17-producing T cells. Thus, germline mutations in human STAT1 define four distinct clinical disorders. Various combinations of viral, mycobacterial and fungal infections are therefore allelic at the human STAT1 locus. These experiments of Nature neatly highlight the clinical and immunological impact of the human genetic dissection of infectious phenotypes.
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Affiliation(s)
- Stephanie Boisson-Dupuis
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA.
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Takezaki S, Yamada M, Kato M, Park MJ, Maruyama K, Yamazaki Y, Chida N, Ohara O, Kobayashi I, Ariga T. Chronic mucocutaneous candidiasis caused by a gain-of-function mutation in the STAT1 DNA-binding domain. THE JOURNAL OF IMMUNOLOGY 2012; 189:1521-6. [PMID: 22730530 DOI: 10.4049/jimmunol.1200926] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Chronic mucocutaneous candidiasis (CMC) is a heterogeneous group of primary immunodeficiency diseases characterized by chronic and recurrent Candida infections of the skin, nails, and oropharynx. Gain-of-function mutations in STAT1 were very recently shown to be responsible for autosomal-dominant or sporadic cases of CMC. The reported mutations have been exclusively localized in the coiled-coil domain, resulting in impaired dephosphorylation of STAT1. However, recent crystallographic analysis and direct mutagenesis experiments indicate that mutations affecting the DNA-binding domain of STAT1 could also lead to persistent phosphorylation of STAT1. To our knowledge, this study shows for the first time that a DNA-binding domain mutation of c.1153C>T in exon 14 (p.T385M) is the genetic cause of sporadic CMC in two unrelated Japanese patients. The underlying mechanisms involve a gain of STAT1 function due to impaired dephosphorylation as observed in the coiled-coil domain mutations.
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Affiliation(s)
- Shunichiro Takezaki
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
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35
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Steroid-like signalling by interferons: making sense of specific gene activation by cytokines. Biochem J 2012; 443:329-38. [PMID: 22452815 DOI: 10.1042/bj20112187] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Many cytokines, hormones and growth factors use the JAK (Janus kinase)/STAT (signal transducer and activator of transcription) pathway for cell signalling and specific gene activation. In the classical model, ligand is said to interact solely with the receptor extracellular domain, which triggers JAK activation of STATs at the receptor cytoplasmic domain. Activated STATs are then said to carry out nuclear events of specific gene activation. Given the limited number of STATs (seven) and the activation of the same STATs by cytokines with different functions, the mechanism of the specificity of their signalling is not obvious. Focusing on IFNγ (interferon γ), we have shown that ligand, receptor and activated JAKs are involved in nuclear events that are associated with specific gene activation, where the receptor subunit IFNGR1 (IFNγ receptor 1) functions as a transcription/co-transcription factor and the JAKs are involved in key epigenetic events. RTKs (receptor tyrosine kinases) such as EGFR [EGF (epidermal growth factor) receptor] and FGFR [FGF (fibroblast growth factor) receptor] also undergo nuclear translocation in association with their respective ligands. EGFR and FGFR, like IFNGR1, have been shown to function as transcription/co-transcription factors. The RTKs also regulate other kinases that have epigenetic effects. Our IFNγ model, as well as the RTKs EGFR and FGFR, have similarities to that of steroid receptor signalling. These systems consist of ligand-receptor-co-activator complexes at the genes that they activate. The co-activators consist of transcription factors and kinases, of which the latter play an important role in the associated epigenetics. It is our view that signalling by cytokines such as IFNγ is but a variation of specific gene activation by steroid hormones.
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Abstract
Since its discovery two decades ago, the activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway by numerous cytokines and growth factors has resulted in it becoming one of the most well-studied intracellular signalling networks. The field has progressed from the identification of the individual components to high-resolution crystal structures of both JAK and STAT, and an understanding of the complexities of the molecular activation and deactivation cycle which results in a diverse, yet highly specific and regulated pattern of transcriptional responses. While there is still more to learn, we now appreciate how disruption and deregulation of this pathway can result in clinical disease and look forward to adoption of the next generation of JAK inhibitors in routine clinical treatment.
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Affiliation(s)
- Hiu Kiu
- Walter & Eliza Hall Institute, 1G Royal Parade, Parkville 3052, Australia
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37
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Moore DL, Goldberg JL. Multiple transcription factor families regulate axon growth and regeneration. Dev Neurobiol 2012; 71:1186-211. [PMID: 21674813 DOI: 10.1002/dneu.20934] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding axon regenerative failure remains a major goal in neuroscience, and reversing this failure remains a major goal for clinical neurology. Although an inhibitory central nervous system environment clearly plays a role, focus on molecular pathways within neurons has begun to yield fruitful insights. Initial steps forward investigated the receptors and signaling pathways immediately downstream of environmental cues, but recent work has also shed light on transcriptional control mechanisms that regulate intrinsic axon growth ability, presumably through whole cassettes of gene target regulation. Here we will discuss transcription factors that regulate neurite growth in vitro and in vivo, including p53, SnoN, E47, cAMP-responsive element binding protein (CREB), signal transducer and activator of transcription 3 (STAT3), nuclear factor of activated T cell (NFAT), c-Jun activating transcription factor 3 (ATF3), sex determining region Ybox containing gene 11 (Sox11), nuclear factor κ-light chain enhancer of activated B cells (NFκB), and Krüppel-like factors (KLFs). Revealing the similarities and differences among the functions of these transcription factors may further our understanding of the mechanisms of transcriptional regulation in axon growth and regeneration.
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Affiliation(s)
- Darcie L Moore
- Bascom Palmer Eye Institute and the Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Florida, USA
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Brzostek-Racine S, Gordon C, Van Scoy S, Reich NC. The DNA damage response induces IFN. THE JOURNAL OF IMMUNOLOGY 2011; 187:5336-45. [PMID: 22013119 DOI: 10.4049/jimmunol.1100040] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This study reveals a new complexity in the cellular response to DNA damage: activation of IFN signaling. The DNA damage response involves the rapid recruitment of repair enzymes and the activation of signal transducers that regulate cell-cycle checkpoints and cell survival. To understand the link between DNA damage and the innate cellular defense that occurs in response to many viral infections, we evaluated the effects of agents such as etoposide that promote dsDNA breaks. Treatment of human cells with etoposide led to the induction of IFN-stimulated genes and the IFN-α and IFN-λ genes. NF-κB, known to be activated in response to DNA damage, was shown to be a key regulator of this IFN gene induction. Expression of an NF-κB subunit, p65/RelA, was sufficient for induction of the human IFN-λ1 gene. In addition, NF-κB was required for the induction of IFN regulatory factor-1 and -7 that are able to stimulate expression of the IFN-α and IFN-λ genes. Cells that lack the NF-κB essential modulator lack the ability to induce the IFN genes following DNA damage. Breaks in DNA are generated during normal physiological processes of replication, transcription, and recombination, as well as by external genotoxic agents or infectious agents. The significant finding of IFN production as a stress response to DNA damage provides a new perspective on the role of IFN signaling.
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Affiliation(s)
- Sabrina Brzostek-Racine
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5200, USA
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Sun J, Kumar PA, Thimmarayappa J, Saini N, Goel P, Maures T, Lu C, Menon RK. Esterase 1 is a novel transcriptional repressor of growth hormone receptor gene expression: a unique noncatalytic role for a carboxyesterase protein. Mol Endocrinol 2011; 25:1351-63. [PMID: 21659478 PMCID: PMC3146247 DOI: 10.1210/me.2011-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/12/2011] [Indexed: 11/19/2022] Open
Abstract
The pleiotropic actions of GH result from its engagement with the GH receptor (GHR). GHR expression is regulated by free fatty acids (FFA). A cDNA phage expression library was screened to identify a phage clone expressing esterase 1 (ES1) binding to the FFA-response element (FARE), L2-D1, in the murine GHR promoter. Ectopically expressed ES1 inhibited GHR promoter activity via effects at two FARE, L2-D1 and L2-A2. Chromatin immunoprecipitation experiments demonstrated specific association of ES1 with the FARE. Catalytically inactive ES1 retained inhibitory activity on the GHR promoter and excluded the possibility that the effect on the GHR promoter was an indirect effect secondary to ES1's actions on the intracellular metabolism of FFA. Ectopically expressed ES1 inhibited the endogenous GHR mRNA and protein expression in 3T3-F442A preadipocytes. Subcellular fractionation and confocal microscopy established that ES1 localizes both to the cytoplasm and the nucleus. Experiments demonstrated chromosome region maintenance 1-dependent nuclear export and the presence of a functional nuclear export signal in ES1. The domain of ES1 responsible for the effect on the GHR promoter was localized to the C-terminal portion of the protein. The in vivo significance of ES1's effect on GHR expression was suggested by decreased liver GHR mRNA expression in mice on a high-fat diet correlating with increased steady-state abundance of liver ES1 mRNA. Our results identify and characterize ES1 as a novel transcriptional regulator of GHR gene expression, thereby establishing a unique nonenzymatic role for a carboxyesterase and expanding the potential biological roles of this protein superfamily.
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Affiliation(s)
- Jinhong Sun
- Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48109-5718, USA
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Noon-Song EN, Ahmed CM, Dabelic R, Canton J, Johnson HM. Controlling nuclear JAKs and STATs for specific gene activation by IFNγ. Biochem Biophys Res Commun 2011; 410:648-53. [PMID: 21689637 DOI: 10.1016/j.bbrc.2011.06.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 06/05/2011] [Indexed: 11/17/2022]
Abstract
We previously showed that gamma interferon (IFNγ) and its receptor subunit, IFNGR1, interacted with the promoter region of IFNγ-activated genes along with transcription factor STAT1α. Recent studies have suggested that activated Janus kinases pJAK2 and pJAK1 also played a role in gene activation by phosphorylation of histone H3 on tyrosine 41. This study addresses the question of the role of activated JAKs in specific gene activation by IFNγ. We carried out chromatin immunoprecipitation (ChIP) followed by PCR in IFNγ treated WISH cells and showed association of pJAK1, pJAK2, IFNGR1, and STAT1 on the same DNA sequence of the IRF-1 gene promoter. The β-actin gene, which is not activated by IFNγ, did not show this association. The movement of activated JAK to the nucleus and the IRF-1 promoter was confirmed by the combination of nuclear fractionation, confocal microscopy and DNA precipitation analysis using the biotinylated GAS promoter. Activated JAKs in the nucleus was associated with phosphorylated tyrosine 41 on histone H3 in the region of the GAS promoter. Unphosphorylated JAK2 was found to be constitutively present in the nucleus and was capable of undergoing activation in IFNγ treated cells, most likely via nuclear IFNGR1. Association of pJAK2 and IFNGR1 with histone H3 in IFNγ treated cells was demonstrated by histone H3 immunoprecipitation. Unphosphorylated STAT1 protein was associated with histone H3 of untreated cells. IFNγ treatment resulted in its disassociation and then re-association as pSTAT1. The results suggest a novel role for activated JAKs in epigenetic events for specific gene activation.
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Affiliation(s)
- Ezra N Noon-Song
- Department of Microbiology and Cell Science, University of Florida, P.O. Box 110700, Gainesville, FL 32611-0700, USA
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41
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Adenovirus sequesters phosphorylated STAT1 at viral replication centers and inhibits STAT dephosphorylation. J Virol 2011; 85:7555-62. [PMID: 21593149 DOI: 10.1128/jvi.00513-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Tyrosine phosphorylation and nuclear translocation of STAT1 indicate activation of interferon (IFN) signal transduction pathways. Here, we demonstrate that tyrosine-phosphorylated STAT1 is targeted by a unique mechanism in adenovirus (Ad)-infected cells. Ad is known to suppress IFN-inducible gene expression; however, we observed that Ad infection prolongs the tyrosine phosphorylation of STAT1 induced by alpha IFN in infected cells. To understand this paradoxical effect, we examined the subcellular localization of STAT1 following Ad infection and found that nuclear, tyrosine-phosphorylated STAT1 accumulates at viral replication centers. This form of STAT1 colocalized with newly synthesized viral DNA. Viral DNA replication, but not viral late gene expression, is required for the regulation of STAT1 phosphorylation. Our results indicate that Ad infection regulates STAT1 dephosphorylation rather than STAT1 phosphorylation. Consistent with this idea, we show that Ad infection disrupts the interaction between STAT1 and its cognate protein tyrosine phosphatase, TC45. Our findings indicate that Ad sequesters phosphorylated STAT1 at viral replication centers and inhibits STAT dephosphorylation. This report suggests a strategy employed by Ad to counteract an active form of STAT1 in the nucleus of infected cells.
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42
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Chen Z, Ma X, Zhang H, Sun X, Shen S, Li Y, Gu Y, Wang Y, Yan S, Yu Q. Negative regulation of interferon-γ/STAT1 signaling through cell adhesion and cell density-dependent STAT1 dephosphorylation. Cell Signal 2011; 23:1404-12. [PMID: 21511030 DOI: 10.1016/j.cellsig.2011.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/29/2011] [Accepted: 04/04/2011] [Indexed: 01/08/2023]
Abstract
Signal transducer and activator of transcription 1 (STAT1) is an important mediator for cytokine signal transduction, particularly IFN-γ. Following IFN-γ stimulation, STAT1 is activated through tyrosine phosphorylation. Little is known about the function and regulation of STAT1 dephosphorylation after activation. We studied the regulation and function of STAT1 dephosphorylation in different types of cells and found that the phosphorylated STAT1 was quickly dephosphorylated in most of epithelial cells. Further studies revealed that the dephosphorylation of STAT1 was regulated by cell shape/adhesion. Actin cytoskeleton and extracellular matrix (ECM) proteins mediated the STAT1 dephosphorylation through the T-cell protein tyrosine phosphatase TCPTP. Inactivation of the dephosphorylation system by cell detachment rendered the cells more sensitive to IFN-γ-induced cell death. Our results revealed a novel mechanism in regulating IFN-γ/STAT1 signaling. This cell adhesion and cell cytoskeleton-dependent STAT1 dephosphorylation system may have a role in IFN-γ-mediated immunosurveillance for cancer cells by inducing anoikis of detached metastatic cancer cells.
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Affiliation(s)
- Zhimin Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
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43
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Santos CI, Costa-Pereira AP. Signal transducers and activators of transcription-from cytokine signalling to cancer biology. Biochim Biophys Acta Rev Cancer 2011; 1816:38-49. [PMID: 21447371 DOI: 10.1016/j.bbcan.2011.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 03/17/2011] [Accepted: 03/22/2011] [Indexed: 10/18/2022]
Abstract
Signal transducers and activators of transcription (STATs) are, as the name indicates, both signal transducers and transcription factors. STATs are activated by cytokines and some growth factors and thus control important biological processes. These include cell growth, cell differentiation, apoptosis and immune responses. Dysregulation of STATs, either due to constitutive activation or function impairment, can have, therefore, deleterious biological consequences. This review places particular emphasis on their structural organization, biological activities and regulatory mechanisms most commonly utilized by cells to control STAT-mediated signalling. STATs also play important roles in cancer and immune deficiencies and are thus being exploited as therapeutic targets.
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Affiliation(s)
- Cristina Isabel Santos
- Imperial College London, Faculty of Medecine, Department of Surgery and Cancer, Hammersmith Hospital Campus, Du Cane Road, London W12 ONN, UK
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44
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Johnson HM, Noon-Song E, Ahmed CM. Controlling Nuclear Jaks and Stats for Specific Gene Activation by Ifn γ and Other Cytokines: A Possible Steroid-like Connection. ACTA ACUST UNITED AC 2011; 2. [PMID: 22924155 DOI: 10.4172/2155-9899.1000112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mechanism of specific gene activation by cytokines that use JAK/STAT signalling pathway is unknown. There are four different types of JAKs and seven different types of STATs. In the classical model of signaling, ligand interacts solely with the receptor extracellular domain, which triggers JAK activation at the receptor cytoplasmic domain. Activated STATs are then said to carry out nuclear events of specific gene activation, including associated epigenetic changes that cause heterochromatin destabilization. Ligand, receptor, and JAKs play no further role in the classical model. Given the limited number of STATs and the activation of the same STATs by cytokines with different functions, the mechanism of the specificity of their signalling is not obvious. Focusing on gamma interferon (IFNγ), we have shown that ligand, receptor, and activated JAKs are involved in nuclear events that are associated with specific gene activation. In this model, receptor subunit IFNGR1 functions as a transcription/cotranscription factor and the JAKs are involved in key epigenetic events that are required for specific gene activation. The model has implications for gene activation in cancer as well as stem cell differentiation.
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Affiliation(s)
- Howard M Johnson
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
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45
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Fei E, Ma X, Zhu C, Xue T, Yan J, Xu Y, Zhou J, Wang G. Nucleocytoplasmic shuttling of dysbindin-1, a schizophrenia-related protein, regulates synapsin I expression. J Biol Chem 2010; 285:38630-40. [PMID: 20921223 PMCID: PMC2992295 DOI: 10.1074/jbc.m110.107912] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 09/23/2010] [Indexed: 01/29/2023] Open
Abstract
Dysbindin-1 is a 50-kDa coiled-coil-containing protein encoded by the gene DTNBP1 (dystrobrevin-binding protein 1), a candidate genetic factor for schizophrenia. Genetic variations in this gene confer a susceptibility to schizophrenia through a decreased expression of dysbindin-1. It was reported that dysbindin-1 regulates the expression of presynaptic proteins and the release of neurotransmitters. However, the precise functions of dysbindin-1 are largely unknown. Here, we show that dysbindin-1 is a novel nucleocytoplasmic shuttling protein and translocated to the nucleus upon treatment with leptomycin B, an inhibitor of exportin-1/CRM1-mediated nuclear export. Dysbindin-1 harbors a functional nuclear export signal necessary for its nuclear export, and the nucleocytoplasmic shuttling of dysbindin-1 affects its regulation of synapsin I expression. In brains of sandy mice, a dysbindin-1-null strain that displays abnormal behaviors related to schizophrenia, the protein and mRNA levels of synapsin I are decreased. These findings demonstrate that the nucleocytoplasmic shuttling of dysbindin-1 regulates synapsin I expression and thus may be involved in the pathogenesis of schizophrenia.
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MESH Headings
- Active Transport, Cell Nucleus/drug effects
- Active Transport, Cell Nucleus/genetics
- Animals
- Antibiotics, Antineoplastic/pharmacology
- Brain/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cytoplasm/genetics
- Cytoplasm/metabolism
- Dysbindin
- Dystrophin-Associated Proteins
- Fatty Acids, Unsaturated/pharmacology
- Gene Expression Regulation
- HEK293 Cells
- Humans
- Karyopherins/antagonists & inhibitors
- Karyopherins/genetics
- Karyopherins/metabolism
- Mice
- Mice, Mutant Strains
- Presynaptic Terminals/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Schizophrenia/genetics
- Schizophrenia/metabolism
- Synapsins/biosynthesis
- Synapsins/genetics
- Exportin 1 Protein
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Affiliation(s)
- Erkang Fei
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Xiaochuan Ma
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Cuiqing Zhu
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ting Xue
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Jie Yan
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yuxia Xu
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jiangning Zhou
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Guanghui Wang
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
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46
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Chen HC, Reich NC. Live cell imaging reveals continuous STAT6 nuclear trafficking. THE JOURNAL OF IMMUNOLOGY 2010; 185:64-70. [PMID: 20498360 DOI: 10.4049/jimmunol.0903323] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The STAT6 transcription factor is essential for the development of protective immunity; however, the consequences of its activity can also contribute to the pathogenesis of autoimmune disease. Tyrosine phosphorylation is known to activate STAT6 in response to cytokine stimulation, but there is a gap in our understanding of the mechanisms by which it enters the nucleus. In this study, live cell imaging was used in conjunction with photobleaching techniques to demonstrate the continual nuclear import of STAT6, independent of tyrosine phosphorylation. The protein domain required for nuclear entry includes the coiled coil region of STAT6 and functions similarly before or after cytokine stimulation. The dynamic nuclear shuttling of STAT6 seems to be mediated by the classical importin-alpha-importin-beta1 system. Although STAT6 is imported to the nucleus continually, it accumulates in the nucleus following tyrosine phosphorylation as a result of its ability to bind DNA. These findings will impact diagnostic approaches and strategies to block the deleterious effects of STAT6 in autoimmunity.
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Affiliation(s)
- Hui-Chen Chen
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA
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47
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Two domains of the V protein of virulent canine distemper virus selectively inhibit STAT1 and STAT2 nuclear import. J Virol 2010; 84:6328-43. [PMID: 20427537 DOI: 10.1128/jvi.01878-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Canine distemper virus (CDV) causes in dogs a severe systemic infection, with a high frequency of demyelinating encephalitis. Among the six genes transcribed by CDV, the P gene encodes the polymerase cofactor protein (P) as well as two additional nonstructural proteins, C and V; of these V was shown to act as a virulence factor. We investigated the molecular mechanisms by which the P gene products of the neurovirulent CDV A75/17 strain disrupt type I interferon (IFN-alpha/beta)-induced signaling that results in the establishment of the antiviral state. Using recombinant knockout A75/17 viruses, the V protein was identified as the main antagonist of IFN-alpha/beta-mediated signaling. Importantly, immunofluorescence analysis illustrated that the inhibition of IFN-alpha/beta-mediated signaling correlated with impaired STAT1/STAT2 nuclear import, whereas the phosphorylation state of these proteins was not affected. Coimmunoprecipitation assays identified the N-terminal region of V (VNT) responsible for STAT1 targeting, which correlated with its ability to inhibit the activity of the IFN-alpha/beta-mediated antiviral state. Conversely, while the C-terminal domain of V (VCT) could not function autonomously, when fused to VNT it optimally interacted with STAT2 and subsequently efficiently suppressed the IFN-alpha/beta-mediated signaling pathway. The latter result was further supported by a single mutation at position 110 within the VNT domain of CDV V protein, resulting in a mutant that lost STAT1 binding while retaining a partial STAT2 association. Taken together, our results identified the CDV VNT and VCT as two essential modules that complement each other to interfere with the antiviral state induced by IFN-alpha/beta-mediated signaling. Hence, our experiments reveal a novel mechanism of IFN-alpha/beta evasion among the morbilliviruses.
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48
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Skjesol A, Hansen T, Shi CY, Thim HL, Jørgensen JB. Structural and functional studies of STAT1 from Atlantic salmon (Salmo salar). BMC Immunol 2010; 11:17. [PMID: 20353564 PMCID: PMC2855521 DOI: 10.1186/1471-2172-11-17] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 03/30/2010] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Type I and type II interferons (IFNs) exert their effects mainly through the JAK/STAT pathway, which is presently best described in mammals. STAT1 is involved in signaling pathways induced by both types of IFNs. It has a domain-like structure including an amino-terminus that stabilizes interaction between STAT dimers in a promoter-binding situation, a coiled coil domain facilitating interactions to other proteins, a central DNA-binding domain, a SH2 domain responsible for dimerization of phosphorylated STATs and conserved phosphorylation sites within the carboxy terminus. The latter is also the transcriptional activation domain. RESULTS A salmon (Salmo salar) STAT1 homologue, named ssSTAT1a, has been identified and was shown to be ubiquitously expressed in various cells and tissues. The ssSTAT1a had a domain-like structure with functional motifs that are similar to higher vertebrates. Endogenous STAT1 was shown to be phosphorylated at tyrosine residues both in salmon leukocytes and in TO cells treated with recombinant type I and type II IFNs. Also ectopically expressed ssSTAT1 was phosphorylated in salmon cells upon in vitro stimulation by the IFNs, confirming that the cloned gene was recognized by upstream tyrosine kinases. Treatment with IFNs led to nuclear translocation of STAT1 within one hour. The ability of salmon STAT1 to dimerize was also shown. CONCLUSIONS The structural and functional properties of salmon STAT1 resemble the properties of mammalian STAT1.
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Affiliation(s)
- Astrid Skjesol
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø N- 9037 Tromsø, Norway
| | - Tom Hansen
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø N- 9037 Tromsø, Norway
| | - Cheng-Yin Shi
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø N- 9037 Tromsø, Norway
- Current address: Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China
| | - Hanna L Thim
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø N- 9037 Tromsø, Norway
| | - Jorunn B Jørgensen
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø N- 9037 Tromsø, Norway
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49
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Najjar I, Fagard R. STAT1 and pathogens, not a friendly relationship. Biochimie 2010; 92:425-44. [PMID: 20159032 PMCID: PMC7117016 DOI: 10.1016/j.biochi.2010.02.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/09/2010] [Indexed: 12/21/2022]
Abstract
STAT1 belongs to the STAT family of transcription factors, which comprises seven factors: STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B and STAT6. STAT1 is a 91 kDa protein originally identified as the mediator of the cellular response to interferon (IFN) α, and thereafter found to be a major component of the cellular response to IFNγ. STAT1 is, in fact, involved in the response to several cytokines and to growth factors. It is activated by cytokine receptors via kinases of the JAK family. STAT1 becomes phosphorylated and forms a dimer which enters the nucleus and triggers the transcription of its targets. Although not lethal at birth, selective gene deletion of STAT1 in mice leads to rapid death from severe infections, demonstrating its major role in the response to pathogens. Similarly, in humans who do not express STAT1, there is a lack of resistance to pathogens leading to premature death. This indicates a key, non-redundant function of STAT1 in the defence against pathogens. Thus, to successfully infect organisms, bacterial, viral or parasitic pathogens must overcome the activity of STAT1, and almost all the steps of this pathway can be blocked or inhibited by proteins produced in infected cells. Interestingly, some pathogens, like the oncogenic Epstein–Barr virus, have evolved a strategy which uses STAT1 activation.
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Affiliation(s)
- Imen Najjar
- INSERM Unité 978, SMBH, 74 rue Marcel Cachin, Bobigny-cedex 93017, France.
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Katsoulidis E, Kaur S, Platanias LC. Deregulation of Interferon Signaling in Malignant Cells. Pharmaceuticals (Basel) 2010; 3:406-418. [PMID: 27713259 PMCID: PMC4033917 DOI: 10.3390/ph3020406] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 12/24/2022] Open
Abstract
Interferons (IFNs) are a family of cytokines with potent antiproliferative, antiviral, and immunomodulatory properties. Much has been learned about IFNs and IFN-activated signaling cascades over the last 50 years. Due to their potent antitumor effects in vitro and in vivo, recombinant IFNs have been used extensively over the years, alone or in combination with other drugs, for the treatment of various malignancies. This review summarizes the current knowledge on IFN signaling components and pathways that are deregulated in human malignancies. The relevance of deregulation of IFN signaling pathways in defective innate immune surveillance and tumorigenesis are discussed.
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Affiliation(s)
- Efstratios Katsoulidis
- Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60611, USA
| | - Surinder Kaur
- Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60611, USA
| | - Leonidas C Platanias
- Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School and Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60611, USA.
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