IκB kinase

The IκB kinase (IKK) is an enzyme complex that is involved in propagating the cellular response to inflammation. The IκB kinase (IKK) is an enzyme complex that is involved in propagating the cellular response to inflammation. The IκB kinase enzyme complex is part of the upstream NF-κB signal transduction cascade. The IκBα (inhibitor of kappa B) protein inactivates the NF-κB transcription factor by masking the nuclear localization signals (NLS) of NF-κB proteins and keeping them sequestered in an inactive state in the cytoplasm. Specifically, IKK phosphorylates the inhibitory IκBα protein. This phosphorylation results in the dissociation of IκBα from NF-κB. NF-κB, which is now free, migrates into the nucleus and activates the expression of at least 150 genes; some of which are anti-apoptotic. In enzymology, an IκB kinase (EC 2.7.11.10) is an enzyme that catalyzes the chemical reaction: Thus, the two substrates of this enzyme are ATP and IκB protein, whereas its two products are ADP and IκB phosphoprotein. This enzyme belongs to the family of transferases, specifically those transferring a phosphate group to the sidechain oxygen atom of serine or threonine residues in proteins (protein-serine/threonine kinases). The systematic name of this enzyme class is ATP: phosphotransferase.