Nuclear factor-kappaB: activation and regulation during toll-like receptor signaling.

Toll-like receptors (TLRs) recognize distinct microbial components to initiate the innate and adaptive immune responses. TLR activation culminates in the expression of appropriate pro-inflammatory and immunomodulatory factors to meet pathogenic challenges. The transcription factor NF-kappaB is the master regulator of all TLR-induced responses and its activation is the pivotal event in TLR-mediated activation of the innate immune response. Many of the key molecular events required for TLR-induced NF-kappaB activation have been elucidated. However, much remains to be learned about the ability of TLRs to generate pathogen-specific responses using a limited number of transcription factors. This review will focus on our current understanding of NF-kappaB activation by TLRs and potential mechanisms for achieving a signal-specific response through NF-kappaB.