ヤマザキ　ソウ   Yamazaki Soh   山﨑　創    所属   東邦大学  医学部 医学科    職種   准教授
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	The nuclear protein IkappaBzeta forms a transcriptionally active complex with nuclear factor-kappaB (NF-kappaB) p50 and Lcn2 promoter via the N- and C-terminal ankyrin repeat motifs
掲載誌名	正式名：J Biol Chem
巻・号・頁	291(39),pp.20739-20752
著者・共著者	Kohda A., Yamazaki S., Sumimoto H.
担当区分	2nd著者
発行年月	2016/09
概要	The nuclear protein IκBζ, comprising the N-terminal trans-activation domain and the C-terminal ankyrin repeat (ANK) domain composed of seven ANK motifs, activates transcription of a subset of nuclear factor-κB (NF-κB)-dependent innate immune genes such as Lcn2 encoding the antibacterial protein lipocalin-2. Lcn2 activation requires formation of a complex containing IκBζ and NF-κB p50, a transcription factor that harbors the DNA-binding Rel homology region but lacks a trans-activation domain, on the promoter with the canonical NF-κB-binding site (κB site) and its downstream cytosine-rich element. Here we show that IκBζ productively interacts with p50 via Asp-451 in the N terminus of ANK1, a residue that is evolutionarily conserved among IκBζ and the related nuclear IκB proteins Bcl-3 and IκBNS Threonine substitution for Asp-451 abrogates direct association with the κB-site-binding protein p50, complex formation with the Lcn2 promoter DNA, and activation of Lcn2 transcription. The basic residues Lys-717 and Lys-719 in the C-terminal region of ANK7 contribute to IκBζ binding to the Lcn2 promoter, probably via interaction with the cytosine-rich element required for Lcn2 activation; glutamate substitution for both lysines results in a loss of transcriptionally active complex formation without affecting direct contact of IκBζ with p50. Both termini of the ANK domain in Bcl-3 and IκBNS function in a manner similar to that of IκBζ to interact with promoter DNA, indicating a common mechanism in which the nuclear IκBs form a regulatory complex with NF-κB and promoter DNA via the invariant aspartate in ANK1 and the conserved basic residues in ANK7.
DOI	10.1074/jbc.M116.719302