IκB kinase
| IkappaB kinase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 2.7.11.10 | ||||||||
| CAS number | 159606-08-3 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / EGO | ||||||||
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The IκB kinase (IKK) is an enzyme complex that is involved in propagating the cellular response to inflammation.[1]
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.[2][3][4] Specifically, IKK phosphorylates the inhibitory IκBα protein.[5] 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.
Catalyzed reaction
In enzymology, an IκB kinase (EC 2.7.11.10) is an enzyme that catalyzes the chemical reaction:
- ATP + IκB protein ADP + IκB phosphoprotein
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:[IκB protein] phosphotransferase.
Structure
The IκB kinase complex is composed of three subunits each encoded by a separate gene:
- IKK-α (also known as IKK1) (CHUK)
- IKK-β (also known as IKK2) (IKBKB)
- IKK-γ (also known as NEMO) (IKBKG)
The α- and β-subunits together are catalytically active whereas the γ-subunit serves a regulatory function.
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Clinical significance
This enzyme participates in 15 pathways related to metabolism: MapK signaling, apoptosis, Toll-like receptor signaling, T-cell receptor signaling, B-cell receptor signaling, insulin signaling, adipokine signaling, Type 2 diabetes mellitus, epithelial cell signaling in helicobacter pylori, pancreatic cancer, prostate cancer, chronic myeloid leukemia, acute myeloid leukemia, and small cell lung cancer.
Inhibition of IκB kinase (IKK) and IKK-related kinases, IKBKE (IKKε) and TANK-binding kinase 1 (TBK1), has been investigated as a therapeutic option for the treatment of inflammatory diseases and cancer.[6] The small-molecule inhibitor of IKK-β SAR113945, developed by Sanofi-Aventis, was evaluated in patients with knee osteoarthritis.[6][7]
References
- ↑ Häcker H, Karin M (October 2006). "Regulation and function of IKK and IKK-related kinases". Sci. STKE. 2006 (357): re13. doi:10.1126/stke.3572006re13. PMID 17047224.
- ↑ 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.
- 1 2 Llona-Minguez S, Baiget J, Mackay SP (2013). "Small-molecule inhibitors of IκB kinase (IKK) and IKK-related kinases". Pharm. Pat. Anal. 2 (4): 481–498. doi:10.4155/ppa.13.31. PMID 24237125.
- ↑ "SAR113945 published clinical trials".
Further reading
- Zandi E, Rothwarf DM, Delhase M, Hayakawa M, Karin M (1997). "The IkappaB kinase complex (IKK) contains two kinase subunits, IKKalpha and IKKbeta, necessary for IkappaB phosphorylation and NF-kappaB activation". Cell. 91 (2): 243–52. doi:10.1016/S0092-8674(00)80406-7. PMID 9346241.
- Viatour P, Merville MP, Bours V, Chariot A (2005). "Phosphorylation of NF-kappaB and IkappaB proteins: implications in cancer and inflammation". Trends. Biochem. Sci. 30 (1): 43–52. doi:10.1016/j.tibs.2004.11.009. PMID 15653325.
External links
- I-kappa B Kinase at the US National Library of Medicine Medical Subject Headings (MeSH)