IκB-ζ (D4I7C) Rabbit mAb #76041

The NF-κB/Rel transcription factors are present in the cytosol in an inactive state complexed with the inhibitory IκB proteins (1-3). Activation occurs via phosphorylation of IκBα at Ser32 and Ser36 followed by proteasome-mediated degradation that results in the release and nuclear translocation of active NF-κB (3-7). IκBα phosphorylation and resulting Rel-dependent transcription are activated by a highly diverse group of extracellular signals including inflammatory cytokines, growth factors, and chemokines. Kinases that phosphorylate IκB at these activating sites have been identified (8).
IκB-ζ (MAIL, INAP) is a unique IκB family member homologous to Bcl-3 and induced by IL-1 and Toll-like receptor (TLR) ligands (9-11). Like other family members, it contains carboxyl terminal ankyrin-repeats responsible for interaction with NF-κB, particularly p50. Unlike classical IκB family members (α, β, ε) which inhibit NF-κB translocation and are rapidly degraded upon cytokine treatment, IκB-ζ is cytokine-inducible and localized to the nucleus where it regulates NF-κB DNA binding and transactivation (12-14). Induction of IκB-ζ is required for TLR/IL-1 induction of a subset of NF-κB target genes, including IL-6 (15). However, the IκB-ζ can also inhibit transactivation of other targets, such as TNF-α (14,15).