Publication Date:
1998-08-28
Description:
A large protein complex mediates the phosphorylation of the inhibitor of kappaB (IkappaB), which results in the activation of nuclear factor kappaB (NF-kappaB). Two subunits of this complex, IkappaB kinase alpha (IKKalpha) and IkappaB kinase beta (IKKbeta), are required for NF-kappaB activation. Purified recombinant IKKalpha and IKKbeta expressed in insect cells were used to demonstrate that each protein can directly phosphorylate IkappaB proteins. IKKalpha and IKKbeta were found to form both homodimers and heterodimers. Both IKKalpha and IKKbeta phosphorylated IkappaB bound to NF-kappaB more efficiently than they phosphorylated free IkappaB. This result explains how free IkappaB can accumulate in cells in which IKK is still active and thus can contribute to the termination of NF-kappaB activation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zandi, E -- Chen, Y -- Karin, M -- AI 43477/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1998 Aug 28;281(5381):1360-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9721103" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Cell Line
;
Dimerization
;
Enzyme Activation
;
HeLa Cells
;
Helix-Loop-Helix Motifs
;
Humans
;
I-kappa B Kinase
;
Leucine Zippers
;
Mutation
;
NF-kappa B/antagonists & inhibitors/*metabolism
;
Phosphorylation
;
Protein-Serine-Threonine Kinases/chemistry/genetics/*metabolism
;
Proto-Oncogene Proteins/*metabolism
;
Recombinant Fusion Proteins/metabolism
;
Recombinant Proteins/metabolism
;
Spodoptera
;
Transcription Factor RelB
;
*Transcription Factors
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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