Fig. 1.

Activation of TLR4 by LPS. LBP facilitates transfer of LPS monomers to CD14 with the help of LBP and CD14 subsequently shifts the endotoxin to TLR4/MD-2 complex. Dimerization of the receptor complex induces the assembly of TIRAP, MyD88, and IRAK kinases in a myddosome at the TIR domain of TLR4 inducing a signaling pathway leading to production of pro-inflammatory cytokines. After endocytosis, TRAM and TRIF associate with TLR4 triggering a signaling pathway which controls production of type I interferons and some other cytokines. The presence of leucine-rich repeats in CD14 and TLR4 is marked by ellipses. The molecules are drawn not to scale