The mammalian NF-κB family of transcription factors functions as a major regulator of innate and adaptive immunity and inflammatory responses, plays critical roles in controlling cell proliferation, differentiation and apoptosis by regulating a wide range of genes that govern these various processes 1. The prototypical NF-κB (p50 and RelA heterodimer) is sequestered and inactivated in the cytoplasm by a family of inhibitors, called IκBs, in unstimulated cells. NF-κB is activated in response to a variety of stimuli, including inflammatory cytokines and viral and bacterial infections, which lead to the activation of the IκB kinase complex (IKK), phosphorylation and degradation of IκBs, and the nuclear translocation of the NF-κB heterodimer.