IUBMB Enzyme Nomenclature


Accepted name: IκB kinase

Reaction: ATP + [IκB protein] = ADP + [IκB phosphoprotein]

Other name(s): CHUK; IKBKA; IKBKB; IKK; IKK-1; IKK-2; inhibitor of NFκB kinase; inhibitor of NF-κB kinase; STK12; TANK-binding kinase 1; TBK1

Systematic name: ATP:[IκB protein] phosphotransferase

Comments: The enzyme phosphorylates IκB proteins at specific serine residues, which marks them for destruction via the ubiquitination pathway. Subsequent degradation of the IkB complex (IKK) activates NF-κB, a translation factor that plays an important role in inflammation, immunity, cell proliferation and apoptosis. If the serine residues are replaced by threonine residues, the activity of the enzyme is decreased considerably.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Regnier, C.H., Song, H.Y., Gao, X., Goeddel, D.V., Cao, Z. and Rothe, M. Identification and characterization of an IκB kinase. Cell 90 (1997) 373-383. [PMID: 9244310]

2. Mercurio, F., Zhu, H., Murray, B.W., Shevchenko, A., Bennett, B.L., Li, J., Young, D.B., Barbosa, M., Mann, M., Manning, A. and Rao, A. IKK-1 and IKK-2: cytokine-activated IκB kinases essential for NF-κB activation. Science 278 (1997) 860-866. [PMID: 9346484]

3. Zandi, E., Rothwarf, D.M., Delhase, M., Hayakawa, M. and Karin, M. The IκB kinase complex (IKK) contains two kinase subunits, IKKα and IKKβ, necessary for IκB phosphorylation and NF-κB activation. Cell 91 (1997) 243-252. [PMID: 9346241]

4. Viatour, P., Merville, M.P., Bours, V. and Chariot, A. Phosphorylation of NF-κB and IκB proteins: implications in cancer and inflammation. Trends Biochem. Sci. 30 (2005) 43-52. [PMID: 15653325]

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