FIG. 1.

Short overview of a TLR signaling cascade. TLR signaling relies on the function of the adaptor protein MyD88, which presumably acts in conjunction with other TLR-specific adaptor proteins, such as Tollip and Mal. These adaptor proteins are necessary for the recruitment and activation of different IL-1 receptor-associated kinase family proteins, which further transmit the signal. This leads to activation of the IκB kinase complex and mitogen-activated protein kinases (c-Jun N-terminal kinase/p38), which induce NF-κB and AP-1-dependent gene transcription, respectively. IKK, IκB kinase complex; IRAK, IL-1 receptor-associated kinase; JNK, c-Jun N-terminal kinase; MKK, mitogen-activated protein kinase kinase; P, phosphate; Ub, ubiquitin.