Severe acute respiratory syndrome coronavirus M protein inhibits type I interferon production by impeding the formation of TRAF3.TANK.TBK1/IKKepsilon complex.
Severe acute respiratory syndrome (SARS) coronavirus is highly pathogenic in humans and evades innate immunity at multiple levels. It has evolved various strategies to counteract the production and action of type I interferons, which mobilize the front-line defense against viral infection. In this study we demonstrate that SARS coronavirus M protein inhibits gene transcription of type I interferons. M protein potently antagonizes the activation of interferon-stimulated response element-dependent transcription by double-stranded RNA, RIG-I, MDA5, TBK1, IKKepsilon, and virus-induced signaling adaptor (VISA) but has no influence on the transcriptional activity of this element when IRF3 or IRF7 is overexpressed. M protein physically associates with RIG-I, TBK1, IKKepsilon, and TRAF3 and likely sequesters some of them in membrane-associated cytoplasmic compartments. Consequently, the expression of M protein prevents the formation of TRAF3.TANK.TBK1/IKKepsilon complex and thereby inhibits TBK1/IKKepsilon-dependent activation of IRF3/IRF7 transcription factors. Taken together, our findings reveal a new mechanism by which SARS coronavirus circumvents the production of type I interferons.
Siu
Kam-Leung
KL
From the Departments of Biochemistry, 21 Sassoon Road, Pokfulam, Hong Kong.
Kok
Kin-Hang
KH
From the Departments of Biochemistry, 21 Sassoon Road, Pokfulam, Hong Kong.
Ng
Ming-Him James
MJ
From the Departments of Biochemistry, 21 Sassoon Road, Pokfulam, Hong Kong.
Poon
Vincent K M
VKM
Microbiology, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Yuen
Kwok-Yung
KY
Microbiology, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Zheng
Bo-Jian
BJ
Microbiology, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Jin
Dong-Yan
DY
From the Departments of Biochemistry, 21 Sassoon Road, Pokfulam, Hong Kong. Electronic address: dyjin@hkucc.hku.hk.
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000086862:Coronavirus M Proteins; D005786:Gene Expression Regulation / Q000276:immunology; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism; D007370:Interferon Type I / Q000235:genetics* / Q000276:immunology*; D007668:Kidney / Q000166:cytology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology / Q000821:virology*; D015398:Signal Transduction / Q000276:immunology; D048008:TNF Receptor-Associated Factor 3 / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000276:immunology* / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D000086862:Coronavirus M Proteins; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; D007370:Interferon Type I; C000706237:M protein, SARS-CoV; C484406:TANK protein, human; D048008:TNF Receptor-Associated Factor 3; C090656:TRAF3 protein, human; D014763:Viral Matrix Proteins; D017346:Protein Serine-Threonine Kinases; C403191:TBK1 protein, human; D051550:I-kappa B Kinase