核因子活化B细胞κ轻链增强子(英語:nuclear factor kappa-light-chain-enhancer of activated B cells,简称为NF-κB)是一种控制DNA转录的蛋白复合体。NF-κB几乎存在于所有类型的动物细胞中并参与细胞对诸多刺激的响应,这些刺激包括应激、细胞因子、自由基、紫外线照射、氧化LDL及细菌或病毒抗原[1][2][3][4][5]。在针对感染的免疫反应中,NF-κB起到了重要的调节作用(κ轻链是免疫球蛋白的重要组成部分)。NF-κB的调控失常与癌症、炎症和自體免疫病、感染性休克、病毒感染以及免疫发育异常有关。NF-κB亦与突触可塑性及记忆过程有着密切关系[6][7][8][9][10]。
核异位编辑
NF-κB易位过程中,IκB蛋白作用不尽相同。IκBα是IκB家族原型蛋白,倾向于结合p65:p50和cRel:p5这两种NF-κB二聚体以抑制NF-κB活化。IκBα磷酸化降解后,释放NF-κB进入细胞核驱动各种基因表达,其中便包括IκBα,重新表达所产生IκBα则结合细胞质NF-κB以抑制通路进一步活化,进行负反馈调节。另一种IκBβ本身以磷酸化形式存在,降解缓慢,虽能结合p65:cRel,复合物IκBβ:p65:cRel可直接结合细胞核内TNF-α启动子等活化B细胞κ轻链增强子(kappa-light-chain-enhancer of activated B cells,κB)位点,促进靶基因转录。一般细胞只磷酸化少量p65,而刺激下p65、p50及cRel水平则显著增加[11][12]。
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^De Dios, Robyn; Nguyen, Leanna; Ghosh, Sankar; McKenna, Sarah; Wright, Clyde J. CpG‐ODN‐mediated TLR9 innate immune signalling and calcium dyshomeostasis converge on the NFκB inhibitory protein IκBβ to drive IL1α and IL1β expression. Immunology. 2020-03-18, 160 (1). ISSN 0019-2805. doi:10.1111/imm.13182.
^Kamata, Hideaki; Tsuchiya, Yoshihiro; Asano, Tomoichiro. IκBβ is a positive and negative regulator of NF-κB activity during inflammation. Cell Research. 2010-10-26, 20 (11). ISSN 1001-0602. doi:10.1038/cr.2010.147.