title: Tom70 mediates activation of interferon regulatory factor 3 on mitochondria.
abstract: Intracellular RNA viruses are sensed by receptors retinoic acid-inducible gene 1 (RIG-I)/melanoma differentiation-associated gene 5 (MDA5) that trigger the formation of MAVS signal complex on mitochondria. Consequently, this leads to the activation of TANK-binding kinase 1 (TBK1) and phosphorylation of interferon regulatory factor 3 (IRF3), both of which constitutively associate with cytosolic chaperone Hsp90. It remains largely unknown how MAVS activates TBK1/IRF3. In this study, we identified translocases of outer membrane 70 (Tom70), a mitochondrial import receptor, to interact with MAVS upon RNA virus infection. Ectopic expression or knockdown of Tom70 could enhance or impair IRF3-mediated gene expression, respectively. Mechanistically, the clamp domain (R192) of Tom70 interacts with the C-terminal motif (EEVD) of Hsp90, thus recruiting TBK1/IRF3 to mitochondria. Disruption of this interaction or mislocation of Tom70 sharply impairs activation of TBK1 and IRF3. Furthermore, host antiviral responses are significantly boosted or crippled in the presence or absence of Tom70. Collectively, our study characterizes Tom70 as a critical adaptor linking MAVS to TBK1/IRF3, revealing that mitochondrion is evolutionarily integrated with innate immunity.
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Xin-Yi
authors.initials: XY
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Wei
authors.forename: He-Xin
authors.initials: HX
authors.lastname: Shi
authors.forename: Yu-Fei
authors.initials: YF
authors.lastname: Shan
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D002460:Cell Line; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007113:Immunity, Innate; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism*; D000072640:Interferon-Induced Helicase, IFIH1; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011971:Receptors, Immunologic; D029082:Sendai virus / Q000276:immunology; D015398:Signal Transduction
chemical_list: D018841:HSP90 Heat-Shock Proteins; D050838:Interferon Regulatory Factor-3; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D034741:RNA, Small Interfering; D011971:Receptors, Immunologic; C402118:TOMM70 protein, human; D017346:Protein Serine-Threonine Kinases; C403191:TBK1 protein, human; C452820:RIGI protein, human; C452815:IFIH1 protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1