Specificity in Toll-like receptor signalling through distinct effector functions of TRAF3 and TRAF6

Nature. 2006 Jan 12;439(7073):204-7. doi: 10.1038/nature04369. Epub 2005 Nov 23.


Toll-like receptors (TLRs) are activated by pathogen-associated molecular patterns to induce innate immune responses and production of pro-inflammatory cytokines, interferons and anti-inflammatory cytokines. TLRs activate downstream effectors through adaptors that contain Toll/interleukin-1 receptor (TIR) domains, but the mechanisms accounting for diversification of TLR effector functions are unclear. To dissect biochemically TLR signalling, we established a system for isolating signalling complexes assembled by dimerized adaptors. Using MyD88 as a prototypical adaptor, we identified TNF receptor-associated factor 3 (TRAF3) as a new component of TIR signalling complexes that is recruited along with TRAF6. Using myeloid cells from TRAF3- and TRAF6-deficient mice, we show that TRAF3 is essential for the induction of type I interferons (IFN) and the anti-inflammatory cytokine interleukin-10 (IL-10), but is dispensable for expression of pro-inflammatory cytokines. In fact, TRAF3-deficient cells overproduce pro-inflammatory cytokines owing to defective IL-10 production. Despite their structural similarity, the functions of TRAF3 and TRAF6 are largely distinct. TRAF3 is also recruited to the adaptor TRIF (Toll/IL-1 receptor domain-containing adaptor-inducing IFN-beta) and is required for marshalling the protein kinase TBK1 (also called NAK) into TIR signalling complexes, thereby explaining its unique role in activation of the IFN response.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Adaptor Proteins, Vesicular Transport / metabolism
  • Animals
  • Antigens, Differentiation / chemistry
  • Antigens, Differentiation / genetics
  • Antigens, Differentiation / metabolism
  • Cell Line
  • Dimerization
  • Gene Expression Regulation
  • Immunity, Innate
  • Interferons / biosynthesis
  • Interleukin-10 / biosynthesis
  • Mice
  • Myeloid Cells / metabolism
  • Myeloid Differentiation Factor 88
  • Protein Serine-Threonine Kinases / metabolism
  • Receptors, Immunologic / chemistry
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism
  • Signal Transduction*
  • Substrate Specificity
  • TNF Receptor-Associated Factor 3 / metabolism*
  • TNF Receptor-Associated Factor 6 / deficiency
  • TNF Receptor-Associated Factor 6 / genetics
  • TNF Receptor-Associated Factor 6 / metabolism*
  • Toll-Like Receptors / metabolism*


  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport
  • Antigens, Differentiation
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • Receptors, Immunologic
  • TICAM-1 protein, mouse
  • TNF Receptor-Associated Factor 3
  • TNF Receptor-Associated Factor 6
  • Toll-Like Receptors
  • Interleukin-10
  • Interferons
  • Tbk1 protein, mouse
  • Protein Serine-Threonine Kinases