Genetic analysis of p53 nuclear importation
Genetic analysis of p53 nuclear importation
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DOI：
10.1038/sj.onc.1210597
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发表时间：
2007-12-13
期刊：
影响因子：
8
通讯作者：
Martinez, J. D.
中科院分区：
文献类型：
--
作者：
Li, Q.;Falsey, R. R.;Martinez, J. D.
p53肿瘤抑制因子激活的关键步骤是其转运到细胞核中;然而，尽管对p53进行了深入的研究，但对其亚细胞定位的调节仍然知之甚少。在这里，我们研究了p53核输入使用一系列的突变细胞系，耐温度敏感的小鼠p53（tsp 53）的生长抑制作用。在这些细胞系中的p53亚细胞定位的检查表明，在大多数细胞中的蛋白质。使用毛地黄皂苷透化的细胞在体外核输入系统，我们表明，从这些细胞系的胞质溶胶不支持核转位的p53核定位信号（NLS）含有底物蛋白，但促进核定位的SV 40 TAgNLS含有基板。互补试验和突变体细胞本身在体外试验中的使用表明，可溶性和不溶性蛋白组分都参与p53核输入。总的来说，我们的研究结果表明，有一个p53 NLS选择性核输入途径，可溶性和不溶性蛋白质参与其功能。
A key step in activation of the p53 tumor suppressor is its transport into the nucleus; however, despite intensive study of p53, the regulation of its subcellular localization is still poorly understood. Here we examined the p53 nuclear importation using a series of mutant cell lines that were resistant to the growth inhibitory effects of temperature-sensitive murine p53 (tsp53). Examination of the p53 subcellular localization in these cell lines showed that the protein was cytoplasmic in most of them. Using a digitonin-permeabilized cell in vitro nuclear import system, we show that cytosols from these cell lines do not support nuclear translocation of a p53 nuclear localization signal (NLS)-containing substrate protein, but promote nuclear localization of a SV40TAgNLS-containing substrate. Complementation assays and use of the mutant cells themselves in the in vitro assays demonstrate that both soluble and insoluble protein components are involved in p53 nuclear import. Collectively, our results suggest that there is a p53 NLS-selective nuclear import pathway and that both soluble and insoluble proteins are involved in its function.