Stable Identifier
Homo sapiens
Activated IKK Complex
Locations in the PathwayBrowser

Co-immunoprecipitation studies and size exclusion chromatography analysis indicate that the high molecular weight (around 700 to 900 kDa) IKK complex is composed of two kinase subunits (IKK1/CHUK/IKBKA and/or IKK2/IKBKB/IKKB) bound to a regulatory gamma subunit (IKBKG/NEMO) (Rothwarf DMet al. 1998; Krappmann D et al. 2000; Miller BS & Zandi E 2001). Variants of the IKK complex containing IKBKA or IKBKB homodimers associated with NEMO may also exist. Crystallographic and quantitative analyses of the binding interactions between N-terminal NEMO and C-terminal IKBKB fragments showed that IKBKB dimers would interact with NEMO dimers resulting in 2:2 stoichiometry (Rushe M et al. 2008). Chemical cross-linking and equilibrium sedimentation analyses of IKBKG (NEMO) suggest a tetrameric oligomerization (dimers of dimers) (Tegethoff S et al. 2003). The tetrameric NEMO could sequester four kinase molecules, yielding an 2xIKBKA:2xIKBKB:4xNEMO stoichiometry (Tegethoff S et al. 2003). The above data suggest that the core IKK complex consists of an IKBKA:IKBKB heterodimer associated with an IKBKG dimer or higher oligomeric assemblies. However, the exact stoichiometry of the IKK complex remains unclear.

Literature References
PubMed ID Title Journal Year
9751060 IKK-gamma is an essential regulatory subunit of the IkappaB kinase complex

Rothwarf, DM, Zandi, E, Natoli, G, Karin, M

Nature 1998
10893415 The I kappa B kinase (IKK) complex is tripartite and contains IKK gamma but not IKAP as a regular component

Krappmann, D, Hatada, EN, Tegethoff, S, Li, J, Klippel, A, Giese, K, Baeuerle, PA, Scheidereit, C

J. Biol. Chem. 2000
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