Supervillin-mediated Suppression of p53 Protein Enhances Cell Survival
Supervillin-mediated Suppression of p53 Protein Enhances Cell Survival
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DOI：
10.1074/jbc.m112.416842
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发表时间：
2013-03-15
影响因子：
4.8
通讯作者：
Luna, Elizabeth J.
中科院分区：
文献类型：
--
作者：
Fang, Zhiyou;Luna, Elizabeth J.
基于整合素的黏附促进细胞存活、细胞运动和侵袭。我们在这里表明，粘附调节蛋白超绒毛蛋白通过降低肿瘤抑制蛋白p53和下游靶基因的水平来提高细胞存活率。rnai介导的超级绒毛蛋白新剪接形式（亚型4）或亚型1和亚型4的敲低会增加p53的数量和细胞死亡，而过度表达任何一种超级绒毛蛋白亚型后，p53水平会降低。依托泊苷或阿霉素诱导的DNA损伤的细胞反应包括内源性超级绒毛蛋白的下调，与p53的增加一致。在dna受损的超级绒毛蛋白敲低细胞中，p53敲低或抑制部分地挽救了细胞代谢活性的丧失，这是细胞增殖的一种衡量标准。p53去泛素化酶USP7/HAUSP的敲低也逆转了超级绒毛蛋白的表型，阻断了超级绒毛蛋白敲低后p53水平的增加，并加剧了超级绒毛蛋白过表达引发的p53水平的下降。相反，超绒毛蛋白的过表达降低了USP7和p53的关联，并减弱了USP7介导的p53去泛素化。USP7直接结合到超级绒毛蛋白N端，可以去泛素化和稳定超级绒毛蛋白。超级绒毛蛋白也通过泛素样蛋白SUMO1衍生化而稳定。这些结果表明，超级绒毛蛋白通过控制p53水平来调节细胞存活，并表明超级绒毛蛋白及其在细胞-底物粘附位点的相互作用伙伴构成了存活信号和细胞运动途径之间的串扰位点。
Integrin-based adhesions promote cell survival as well as cell motility and invasion. We show here that the adhesion regulatory protein supervillin increases cell survival by decreasing levels of the tumor suppressor protein p53 and downstream target genes. RNAi-mediated knockdown of a new splice form of supervillin (isoform 4) or both isoforms 1 and 4 increases the amount of p53 and cell death, whereas p53 levels decrease after overexpression of either supervillin isoform. Cellular responses to DNA damage induced by etoposide or doxorubicin include down-regulation of endogenous supervillin coincident with increases in p53. In DNA-damaged supervillin knockdown cells, p53 knockdown or inhibition partially rescues the loss of cell metabolic activity, a measure of cell proliferation. Knockdown of the p53 deubiquitinating enzyme USP7/HAUSP also reverses the supervillin phenotype, blocking the increase in p53 levels seen after supervillin knockdown and accentuating the decrease in p53 levels triggered by supervillin overexpression. Conversely, supervillin overexpression decreases the association of USP7 and p53 and attenuates USP7-mediated p53 deubiquitination. USP7 binds directly to the supervillin N terminus and can deubiquitinate and stabilize supervillin. Supervillin also is stabilized by derivatization with the ubiquitin-like protein SUMO1. These results show that supervillin regulates cell survival through control of p53 levels and suggest that supervillin and its interaction partners at sites of cell-substrate adhesion constitute a locus for cross-talk between survival signaling and cell motility pathways.