The biochemistry of NF-κB activation. NF-κB is sequestered in the cytoplasm by the inhibitory IκB proteins. Stimulation by a diverse array of pathogens and other inducers including viruses, cytokines, and stress-inducing agents leads to the activation of signaling cascades that culminate with the activation of the IKK complex and phosphorylation of the IκB inhibitor. NF-κB DNA binding subunits are released and translocate to the nucleus where they transactivate NF-κB responsive genes containing the decameric sequence (5′-GGGRNNYYCC-3′). Target genes are selectively regulated by the distinct transcriptional activation potential of different NF-κB subunit combinations. TBP, TATA binding protein.