IKK complex IKK complex with phosphorylated IKK beta Activation of IKK complex Authored: Rudd, C.E., de Bono, B, Garapati, P V, 2008-01-24 15:53:10 EC Number: 2.7.11 Pubmed17047224 Reactome Database ID Release 43202500 Reactome, http://www.reactome.org ReactomeREACT_12581 Reviewed: Trowsdale, J, 2008-02-26 12:02:59 The IkB kinase (IKK) complex serves as the master regulator for the activation of NF-kB by various stimuli. It contains two catalytic subunits, IKK alpha and IKK beta, and a regulatory subunit, IKKgamma/NEMO. The activation of IKK complex is dependent on the phosphorylation of IKK alpha/beta at its activation loop and the K63-linked ubiquitination of NEMO. This basic trimolecular complex is referred to as the IKK complex. <br>IKK subunits have a N-term kinase domain a leucine zipper (LZ) motifs, a helix-loop-helix (HLH) and a C-ter NEMO binding domain (NBD). IKK catalytic subunits are dimerized through their LZ motifs. IKK beta is the major IKK catalytic subunit for NF-kB activation. Activated TAK1 phosphorylate IKK beta on serine residues (S177 and S181) in the activation loop and thus activate the IKK kinase activity, leading to the IkB alpha phosphorylation and NF-kB activation. has a Stoichiometric coefficient of 2