NEMO differentially regulates TCR and TNF-伪 induced NF-魏B pathways and has an inhibitory role in TCR-induced NF-魏B activation

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• 作者：Kai Wang¹ ; Liang-Hui Diao¹ ; Yu Gong ; Xin Liu ; Yingqiu Li ; ^{lsslyq@mail.sysu.edu.cn}
• 关键词：NEMO ; NF-魏B essential modulator ; siRNA ; small interfering RNA ; TCR ; T cell receptor ; CBM ; CARMA1-Bcl10-MALT1 complex ; IS ; Immunological synapse ; shRNA ; short hairpin RNA ; SM ; Soluble membrane ; DI ; Detergent Insoluble cytoskeleton fraction ; AICD ; activati
• 刊名：Cellular Signalling
• 出版年：2012
• 期刊代码：42_08986568
• 类别：bio
• 出版时间：August, 2012
• 卷：24
• 期：8
• 页码：1556-1564
• 文件大小：1315 K

摘要

NF-魏B essential modulator (NEMO), the regulatory subunit of the I魏B kinase (IKK) complex, is an essential adaptor both for inflammation stimuli and TCR-induced NF-魏B activation. However, the exact mechanism of its function has not been fully understood. Here, we report that knockdown of NEMO by RNA interference in Jurkat E6.1 cells enhanced TCR-induced NF-魏B report gene activity and IL-2 production by promotion of I魏B伪 degradation and p65 nuclear translocation, whereas inhibited TNF-伪 and LPS-induced I魏B伪 degradation without influencing the phosphorylation of MAPKs. In human primary T and Jurkat E6.1 cells, both CD3/CD28 and PMA/Ionomycin induced NF-魏B activation showed a para-curve correlation with the dosage of small interfering RNA targeting NEMO (siNEMO): the NF-魏B report gene activity was increased along with ascending doses of transfected siNEMO and reached the highest activity when knockdown about 70%of NEMO, then turned to decline and gradually be blocked once almost thoroughly knockdown of NEMO. Meanwhile, TNF-伪 induced NF-魏B was always inhibited no matter how much NEMO was knockdown. Subcellular fractionation results suggested that upon CD3/CD28 costimulation, NEMO and IKK尾 may not cotranslocate to cytoskeleton fraction as a conventional NEMO/IKK complex with a static stoichiometric ratio, instead the ratio of NEMO: IKK尾 continuously shift from high to low. Depletion of NEMO accelerated TCR-induced cytoskeleton translocation of IKK尾. Altogether, this study suggests that NEMO may function as a rheostat exerting a negative action on TCR-induced NF-魏B activation and differentially regulates TNF-伪 and TCR-induced NF-魏B pathways.