MAVS activates TBK1 and IKKε through TRAFs in NEMO dependent and independent manner
| Autor: | Chenguang Wang, Ji-Ming Feng, Jianzhong Xi, Qifei Jiang, Jianli Tao, Xiang Zhou, Run Fang, Zhengfan Jiang, Yukun Guan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Cultured tumor cells Artificial Gene Amplification and Extension environment and public health Sendai virus Biochemistry Polymerase Chain Reaction Ligases 0302 clinical medicine Ubiquitin TANK-binding kinase 1 Chemical Precipitation Biology (General) Phosphorylation Post-Translational Modification Enzyme-Linked Immunoassays skin and connective tissue diseases biology Chemical Reactions Signal transducing adaptor protein Ubiquitin ligase I-kappa B Kinase Precipitation Techniques Enzymes Chemistry 030220 oncology & carcinogenesis Physical Sciences 293T cells Cell lines biological phenomena cell phenomena and immunity Biological cultures Signal Transduction Research Article Immunoprecipitation QH301-705.5 Immunology Protein Serine-Threonine Kinases Microbiology Precipitates 03 medical and health sciences Virology Genetics Humans HeLa cells Immunoassays Molecular Biology Techniques Transcription factor Molecular Biology Adaptor Proteins Signal Transducing HEK 293 cells Ubiquitination Biology and Life Sciences Proteins Reverse Transcriptase-Polymerase Chain Reaction RC581-607 Cell cultures Molecular biology Immunity Innate Research and analysis methods enzymes and coenzymes (carbohydrates) 030104 developmental biology HEK293 Cells biology.protein Enzymology Immunologic Techniques Parasitology Immunologic diseases. Allergy |
| Zdroj: | PLoS Pathogens PLoS Pathogens, Vol 13, Iss 11, p e1006720 (2017) |
| ISSN: | 1553-7374 |
| Popis: | Mitochondrial antiviral-signaling protein (MAVS) transmits signals from RIG-I-like receptors after RNA virus infections. However, the mechanism by which MAVS activates downstream components, such as TBK1 and IKKα/β, is unclear, although previous work suggests the involvement of NEMO or TBK1-binding proteins TANK, NAP1, and SINTBAD. Here, we report that MAVS-mediated innate immune activation is dependent on TRAFs, partially on NEMO, but not on TBK1-binding proteins. MAVS recruited TBK1/IKKε by TRAFs that were pre-associated with TBK1/IKKε via direct interaction between the coiled-coil domain of TRAFs and the SDD domain of TBK1/IKKε. TRAF2−/−3−/−5−/−6−/− cells completely lost RNA virus responses. TRAFs’ E3 ligase activity was required for NEMO activation by synthesizing ubiquitin chains that bound to NEMO for NF-κB and TBK1/IKKε activation. NEMO-activated IKKα/β were important for TBK1/IKKε activation through IKKα/β-mediated TBK1/IKKε phosphorylation. Moreover, individual TRAFs differently mediated TBK1/IKKε activation and thus fine-tuned antiviral immunity under physiological conditions. Author summary Innate immunity is the first line of defense against virus infection. RIG-I-like receptors (RLRs) recognize various viral RNA from RNA viruses and initiate host antiviral responses to produce type I interferons (IFNs) and other cytokines. RLRs sense distinct types of viruses by sharing a common adaptor protein called mitochondrial antiviral-signaling protein (MAVS). Although it has been well studied how RLRs recruit and activate MAVS upon virus infection, it remains to be elucidated how MAVS activates its downstream components, including kinases TBK1/IKKε and the IKK complex. Here, by using TANK−/−NAP1−/−SINTBAD−/−, TRAF2−/−3−/−5−/−6−/− and TRAF2−/−3−/−5−/−6−/−NEMO−/− 293T cells combined with reconstitution experiments, we discovered that MAVS recruited TBK1/IKKε via TRAFs through pre-associated TRAFs-TBK1/IKKε complex. TBK1/IKKε activation required both TRAFs-mediated TBK1 autophosphorylation and TRAFs-NEMO-IKKβ-mediated TBK1 phosphorylation. We demonstrated that TRAFs’ E3 ligase activity was solely required for NEMO and IKKα/β activation. IKKα/β were crucial for both TBK1 and NF-κB activation. Our results thus demonstrated that MAVS activates TBK1/IKKε through TRAFs in both NEMO-dependent and independent manner. Importantly, a minimal amount of IFNs was produced independent of NF-κB activation during virus infection and that individual TRAFs differently mediated TBK1/IKKε activation, thus fine-tuned antiviral immunity under physiological conditions. |
| Databáze: | OpenAIRE |
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