Catalytic domain of the Serine/Threonine kinase, Inhibitor of Nuclear Factor-KappaB Kinase (IKK) alpha
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. IKKalpha is involved in the non-canonical or alternative pathway of regulating Nuclear Factor-KappaB (NF-kB) proteins, a family of transcription factors which are critical in many cellular functions including inflammatory responses, immune development, cell survival, and cell proliferation, among others. The non-canonical pathway functions in cells lacking NEMO (NF-kB Essential MOdulator) and IKKbeta. It is induced by a subset of TNFR family members including CD40, RANK, and B cell-activating factor receptor. IKKalpha processes the Inhibitor of NF-kB (IkB)-like C-terminus of NF-kB2/p100 to produce p52, allowing the p52/RelB dimer to migrate to the nucleus. This pathway is dependent on NIK (NF-kB Inducing Kinase) which phosphorylates and activates IKKalpha. The IKKalpha subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
Jiyao W et al.(2023). "The conserved domain database in 2023.",