Prohibitin interacts with RNF2 and regulates E2F1 function via dual pathways
Prohibitin interacts with RNF2 and regulates E2F1 function via dual pathways
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DOI：
10.1038/sj.onc.1210806
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发表时间：
2008-03-13
期刊：
影响因子：
8
通讯作者：
Kang, S.
中科院分区：
文献类型：
--
作者：
Choi, D.;Lee, S-J;Kang, S.
抑制素是一种肿瘤抑制蛋白，在细胞周期调控和增殖相关基因的转录调控中发挥重要作用。最近的研究报道，抑制蛋白的生长抑制特性表现在其与E2 F家族蛋白的物理相互作用及其随后的转录活性抑制。在此，我们报告，抑制素与环指蛋白2（RNF 2），PcG（polycomb组）蛋白质家族的成员，相互作用，这两种蛋白质通过双重途径调节E2 F1的活性：直接，抑制素介导的途径和间接，p16介导的E2 F1转录调控途径。免疫共沉淀实验表明，内源性抑制素与内源性RNF 2相互作用。有趣的是，RNF 2和prohibitin的表达量在翻译后水平受到相互依赖的影响。此外，使用RNA干扰技术去除内源性RNF 2或prohibitin增加了p16蛋白的表达水平，导致E2 F1通过p16-CDK 4-Rb途径的转录活性降低。此外，染色质免疫沉淀分析表明，RNF 2被募集到E2 F1反应启动子沿着抑制蛋白抑制E2 F1的转录活性。细胞增殖也受到拟南芥素-RNF 2相互作用的调节。这些结果表明RNF 2-prohibitin复合物通过双重途径调节E2 F1的活性。
Prohibitin, a tumor suppresser protein, plays an important role in the transcriptional regulation of various genes involved in cell-cycle control and proliferation. Recent studies have reported that the growth-suppressive property of the prohibitin protein is exhibited in its physical interaction with E2F family proteins and its subsequent repression of their transcriptional activity. Herein, we report that prohibitin interacts with RING finger protein 2 (RNF2), a member of the PcG (polycomb-group) family of proteins, and that the two proteins regulate the activity of E2F1 via dual pathways: the direct, prohibitin-mediated pathway and the indirect, p16-mediated pathway of E2F1 transcriptional regulation. Co-immunoprecipitation experiments showed that endogenous prohibitin interacts with endogenous RNF2. Interestingly, the expressed amounts of RNF2 and prohibitin were interdependently affected at the post-translational level. Furthermore, the depletion of either endogenous RNF2 or prohibitin using the RNA interference technique increased the level of p16 protein expression, resulting in a decrease in the transcriptional activity of E2F1 via the p16-CDK4-Rb pathway. In addition, chromatin immunoprecipitation assays showed that RNF2 was recruited to E2F1-response promoters along with prohibitin to inhibit the transcriptional activity of E2F1. Cell proliferation was also regulated by the prohibitin-RNF2 interaction. These results suggest that the RNF2-prohibitin complex regulates the activity of E2F1 via dual pathways.