IKBKB, also named as IKKB, IKK2, NFKBIKB and IKK-B, belongs to the protein kinase superfamily, Ser/Thr protein kinase family and I-kappa-B kinase subfamily. IKBKB is a Serine kinase that plays an essential role in the NF-kappa-B signaling pathway. It acts as part of the canonical IKK complex in the conventional pathway of NF-kappa-B activation and phosphorylates inhibitors of NF-kappa-B on 2 critical serine residues. In addition to the NF-kappa-B inhibitors, IKBKB phosphorylates several other components of the signaling pathway including NEMO/IKBKG, NF-kappa-B subunits RELA and NFKB1, as well as IKK-related kinases TBK1 and IKBKE. It also phosphorylates other substrates including NCOA3, BCL10 and IRS1. Within the nucleus, IKBKB acts as an adapter protein for NFKBIA degradation in UV-induced NF-kappa-B activation.