Activated IKK Complex IKK complex Activated TAK1 mediates phosphorylation of the IKK Complex Authored: Luo, F, 2005-11-10 11:23:18 EC Number: 2.7.11 Edited: Shamovsky, V, 2009-12-16 In humans, the IKKs - IkB kinase (IKK) complex serves as the master regulator for the activation of NF-kB by various stimuli. The IKK complex contains two catalytic subunits, IKK alpha and IKK beta associated with a regulatory subunit, NEMO (IKKgamma). The activation of the IKK complex and the NFkB mediated antiviral response are dependent on the phosphorylation of IKK alpha/beta at its activation loop and the ubiquitination of NEMO [Solt et al 2009; Li et al 2002]. NEMO ubiquitination by TRAF6 is required for optimal activation of IKKalpha/beta; it is unclear if NEMO subunit undergoes K63-linked or linear ubiquitination.<p>This basic trimolecular complex is referred to as the IKK complex. Each catalytic IKK subunit has an N-terminal kinase domain and leucine zipper (LZ) motifs, a helix-loop-helix (HLH) and a C-terminal NEMO binding domain (NBD). IKK catalytic subunits are dimerized through their LZ motifs.<p>IKK beta is the major IKK catalytic subunit for NF-kB activation. Phosphorylation in the activation loop of IKK beta requires Ser177 and Ser181 and thus activates the IKK kinase activity, leading to the IkB alpha phosphorylation and NF-kB activation. Pubmed11460167 Pubmed12221085 Pubmed17496917 Pubmed19666475 Pubmed9744859 Reactome Database ID Release 43168184 Reactome, http://www.reactome.org ReactomeREACT_6935 Reviewed: Fitzgerald, Katherine A, 2012-11-13 Reviewed: Kufer, TA, 2011-04-28 Reviewed: Napetschnig, Johanna, 2012-11-16 Reviewed: Rittinger, K, 2011-06-06 Reviewed: Wong, Edmond, 2011-06-06 has a Stoichiometric coefficient of 4