Polo-like kinase 1 (Plk1) inhibits p53 function by physical interaction and phosphorylation
Polo-like kinase 1 (Plk1) inhibits p53 function by physical interaction and phosphorylation
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DOI：
10.1074/jbc.m314182200
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发表时间：
2004-06-11
影响因子：
4.8
通讯作者：
Nakagawara, A
中科院分区：
文献类型：
--
作者：
Ando, K;Ozaki, T;Nakagawara, A
Polo样激酶1（Plk 1）在细胞周期的M期调控中具有重要作用。除了其细胞周期调节功能外，Plk 1在肿瘤发生中具有潜在作用。在此，我们首次发现Plk 1与哺乳动物培养细胞中的肿瘤抑制因子p53物理结合，并抑制其反式激活活性以及促凋亡功能。在顺铂诱导的人神经母细胞瘤SH-SY 5 Y细胞凋亡过程中，Plk 1的表达水平在mRNA和蛋白水平上均显著降低，而顺铂处理引起p53的显著稳定。使用一系列p53缺失突变体的系统免疫沉淀分析表明，p53的序列特异性DNA结合区是必需的，并且足以与Plk 1进行物理相互作用。激光共聚焦显微镜显示，异位过表达的Plk 1与内源性p53共定位于哺乳动物细胞核中。外源Plk 1和p53在p53缺陷型肺癌H1299细胞中的表达大大降低了p53介导的来自p53响应性p21（WAF 1）、MDM 2和BAX启动子的转录，而Plk 1的激酶缺陷型突变体形式未能降低p53的转录活性。与荧光素酶报告基因分析一致，Plk 1能够阻断内源性p21（WAF 1）的p53依赖性诱导。此外，Plk 1抑制H1299细胞中p53的促凋亡功能。有趣的是，ATM减弱了Plk 1介导的p53抑制。因此，我们目前的研究结果强烈表明，p53是Plk 1的关键目标，其功能通过与Plk 1的物理相互作用而被废除。
Polo-like kinase 1 (Plk1) has an important role in the regulation of M phase of the cell cycle. In addition to its cell cycle-regulatory function, Plk1 has a potential role in tumorigenesis. Here we found for the first time that Plk1 physically binds to the tumor suppressor p53 in mammalian cultured cells, and inhibits its transactivation activity as well as its pro-apoptotic function. During the cisplatin-induced apoptosis in human neuroblastoma SH-SY5Y cells, the expression level of Plk1 was significantly decreased both at mRNA and protein levels, whereas cisplatin treatment caused a remarkable stabilization of p53. Systematic immunoprecipitation analyses using a series of deletion mutants of p53 revealed that a sequence-specific DNA-binding region of p53 is required and sufficient for the physical interaction with Plk1. The ectopically overexpressed Plk1 was co-localized with the endogenous p53 in mammalian cell nucleus, as shown by confocal laser microscopy. Expression of exogenous Plk1 and p53 in p53-deficient lung carcinoma H1299 cells greatly decreased the p53-mediated transcription from the p53-responsive p21(WAF1), MDM2, and BAX promoters, whereas the kinase-deficient mutant form of Plk1 failed to reduce the transcriptional activity of p53. Consistent with the luciferase reporter analysis, Plk1 had an ability to block the p53-dependent induction of the endogenous p21(WAF1). In addition, Plk1 inhibited the pro-apoptotic function of p53 in H1299 cells. Intriguingly, Plk1-mediated repression of p53 was attenuated with ATM. Thus, our present findings strongly suggest that p53 is a critical target of Plk1, and its function is abrogated through the physical interaction with Plk1.