Lipopolysaccharide-mediated interferon regulatory factor activation involves TBK1-IKKepsilon-dependent Lys(63)-linked polyubiquitination and phosphorylation of TANK/I-TRAF.
Type I interferon gene induction relies on IKK-related kinase TBK1 and IKKepsilon-mediated phosphorylations of IRF3/7 through the Toll-like receptor-dependent signaling pathways. The scaffold proteins that assemble these kinase complexes are poorly characterized. We show here that TANK/ITRAF is required for the TBK1- and IKKepsilon-mediated IRF3/7 phosphorylations through some Toll-like receptor-dependent pathways and is part of a TRAF3-containing complex. Moreover, TANK is dispensable for the early phase of double-stranded RNA-mediated IRF3 phosphorylation. Interestingly, TANK is heavily phosphorylated by TBK1-IKKepsilon upon lipopolysaccharide stimulation and is also subject to lipopolysaccharide- and TBK1-IKKepsilon-mediated Lys(63)-linked polyubiquitination, a mechanism that does not require TBK1-IKKepsilon kinase activity. Thus, we have identified TANK as a scaffold protein that assembles some but not all IRF3/7-phosphorylating TBK1-IKKepsilon complexes and demonstrated that these kinases possess two functions, namely the phosphorylation of both IRF3/7 and TANK as well as the recruitment of an E3 ligase for Lys(63)-linked polyubiquitination of their scaffold protein, TANK.
Gatot
Jean-Stéphane
JS
Interdisciplinary Cluster for Applied Genoproteomics, Medical Chemistry, and Virology/Immunology units, University of Liege, Sart-Tilman, 4000 Liège, Belgium.
Gioia
Romain
R
Chau
Tieu-Lan
TL
Patrascu
Félicia
F
Warnier
Michael
M
Close
Pierre
P
Chapelle
Jean-Paul
JP
Muraille
Eric
E
Brown
Keith
K
Siebenlist
Ulrich
U
Piette
Jacques
J
Dejardin
Emmanuel
E
Chariot
Alain
A
D048868:Adaptor Proteins, Signal Transducing / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation / Q000276:immunology; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000276:immunology* / Q000378:metabolism; D050835:Interferon Regulatory Factors / Q000276:immunology / Q000378:metabolism; D007668:Kidney / Q000166:cytology; D008070:Lipopolysaccharides / Q000276:immunology* / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008239:Lysine / Q000737:chemistry / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000276:immunology* / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D020798:Two-Hybrid System Techniques; D054875:Ubiquitination