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The IκB kinase (IKK) 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 keep them sequestered in an inactive state in the cytoplasm.[1][2][3] IKK specifically phosphorylates the inhibitory IκBα protein.[4] This phosphorylation results in the dissociation of IκBα from NF-κB and thereby activates NF-κB.
[edit] Structure
The IκB kinase complex is comprised of three subunits each encoded by a separate gene:
The α- and β-subunits together are catalytically active whereas the γ-subunit serves a regulatory function.
[edit] References
- ^ Jacobs MD, Harrison SC (1998). "Structure of an IkappaBalpha/NF-kappaB complex". Cell 95 (6): 749–58. doi:10.1016/S0092-8674(00)81698-0. PMID 9865693.
- ^ Régnier CH, Song HY, Gao X, Goeddel DV, Cao Z, Rothe M (1997). "Identification and characterization of an IkappaB kinase". Cell 90 (2): 373–83. doi:10.1016/S0092-8674(00)80344-X. PMID 9244310.
- ^ Mercurio F, Zhu H, Murray BW, Shevchenko A, Bennett BL, Li J, Young DB, Barbosa M, Mann M, Manning A, Rao A (1997). "IKK-1 and IKK-2: cytokine-activated IkappaB kinases essential for NF-kappaB activation". Science 278 (5339): 860–6. doi:10.1126/science.278.5339.860. PMID 9346484.
- ^ Karin M (1999). "How NF-kappaB is activated: the role of the IkappaB kinase (IKK) complex". Oncogene 18 (49): 6867–74. doi:10.1038/sj.onc.1203219. PMID 10602462.
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