Fig. 1.

Signalling pathways leading to NF-κB activation. The canonical pathways include TLR/IL-1 receptors, leading to IRAK activation and IKK-β phosphorylation, intracellular viral receptors including the RNA helicases and PKR which activate IKK-β, the TCR activation pathway, leading to IKK-α IKK-β activation, TNFR activation which signals via TRADD to activate IKK-β, and the alternative pathway induced by CD40–CD40L activation, lymphotoxin-β or RANKL leading to activation of NIK and IKK-α.