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Updated: Jul 12, 2026

Analysis of the c-KIT Ligand Promoter Using Chromatin Immunoprecipitation
Published on: June 27, 2017
Positive and negative regulation of IkappaB kinase activity through IKKbeta subunit phosphorylation
M Delhase1, M Hayakawa, Y Chen
1Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA.
Abstract:
IkappaB [inhibitor of nuclear factor kappaB (NF-kappaB)] kinase (IKK) phosphorylates IkappaB inhibitory proteins, causing their degradation and activation of transcription factor NF-kappaB, a master activator of inflammatory responses. IKK is composed of three subunits-IKKalpha and IKKbeta, which are highly similar protein kinases, and IKKgamma, a regulatory subunit. In mammalian cells, phosphorylation of two sites at the activation loop of IKKbeta was essential for activation of IKK by tumor necrosis factor and interleukin-1. Elimination of equivalent sites in IKKalpha, however, did not interfere with IKK activation. Thus, IKKbeta, not IKKalpha, is the target for proinflammatory stimuli. Once activated, IKKbeta autophosphorylated at a carboxyl-terminal serine cluster. Such phosphorylation decreased IKK activity and may prevent prolonged activation of the inflammatory response.
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