Fig. 5.

Signal transduction pathways of Toll-like receptors. The binding of the ligand (LPS/LBP/CD14; MD-2) to TLR leads to the association of adapter molecules such as MyD88, Toll-interacting Protein (TOLLIP), the protein kinase IRAK, and TRAF6 (TNF-receptor associated factor 6). TRAF6 activates IκB kinases 1 and 2 (IKK-1/2) via the kinase TAK1 (TGF-β activated kinase). These kinases phosphorylate IκB, which leads to the degradation of the inhibitory protein and releases NF-κB as a dimer. NF-κB migrates into the cell nucleus and induces a transcriptional activation of proinflammatory and immunomodulatory genes ([76] with kind permission)