Toll/IL-1 receptor domain-containing adaptor inducing IFN-beta (TRIF) associates with TNF receptor-associated factor 6 and TANK-binding kinase 1, and activates two distinct transcription factors, NF-kappa B and IFN-regulatory factor-3, in the Toll-like receptor signaling.
We previously reported a new Toll/IL-1R (TIR)-containing molecule, named TIR domain-containing adaptor inducing IFN-beta (TRIF). Although initial study indicated that TRIF possesses the ability to activate not only the NF-kappaB-dependent but also the IFN-beta promoters, the molecular mechanisms of TRIF-induced signaling are poorly understood. In this study, we investigated the signaling cascades through TRIF. TNF receptor-associated factor (TRAF)6 interacted with TRIF through the TRAF domain of TRAF6 and TRAF6-binding motifs found in the N-terminal portion of TRIF. Disruption of TRAF6-binding motifs of TRIF disabled it from associating with TRAF6, and resulted in a reduction in the TRIF-induced activation of the NF-kappaB-dependent but not IFN-beta promoter. TANK-binding kinase (TBK)-1, which was recently reported to be a kinase of IFN regulatory factor-3, which is an essential transcription factor for IFN-beta expression, also associated with the N-terminal region of TRIF. Moreover, the association between TRIF and TBK1 appeared to require the kinase activity of TBK1, as well as phosphorylation of TRIF. Because TRAF6 and TBK1 bind close the region of TRIF, it seems that TRAF6 physically prevents the association between TRIF and TBK1. Taken together, these results demonstrate that TRIF associates with TRAF6 and TBK1 independently, and activates two distinct transcription factors, NF-kappaB and IFN regulatory factor-3, respectively.
Sato
Shintaro
S
Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Suita, Japan.
Sugiyama
Masanaka
M
Yamamoto
Masahiro
M
Watanabe
Yasuyuki
Y
Kawai
Taro
T
Takeda
Kiyoshi
K
Akira
Shizuo
S
D033942:Adaptor Proteins, Vesicular Transport / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D020816:Amino Acid Motifs / Q000276:immunology; D000818:Animals; D001667:Binding, Competitive / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D051550:I-kappa B Kinase; D050838:Interferon Regulatory Factor-3; D016899:Interferon-beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011956:Receptors, Cell Surface / Q000378:metabolism / Q000502:physiology*; D017472:Receptors, Interleukin-1 / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology*; D048029:TNF Receptor-Associated Factor 6; D051193:Toll-Like Receptors; D014157:Transcription Factors / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D033942:Adaptor Proteins, Vesicular Transport; D004268:DNA-Binding Proteins; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; C494233:Irf3 protein, mouse; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D010446:Peptide Fragments; D011506:Proteins; D011956:Receptors, Cell Surface; D017472:Receptors, Interleukin-1; C470409:TICAM1 protein, human; D048029:TNF Receptor-Associated Factor 6; D051193:Toll-Like Receptors; D014157:Transcription Factors; D016899:Interferon-beta; C498588:Tbk1 protein, mouse; D017346:Protein Serine-Threonine Kinases; C403191:TBK1 protein, human; C496559:CHUK protein, human; C496564:Chuk protein, mouse; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse