Phosphorylation of p53 on key serines is dispensable for transcriptional activation and apoptosis
Phosphorylation of p53 on key serines is dispensable for transcriptional activation and apoptosis
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DOI：
10.1074/jbc.m410233200
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发表时间：
2004-12-17
影响因子：
4.8
通讯作者：
Vassilev, LT
中科院分区：
文献类型：
--
作者：
Thompson, T;Tovar, C;Vassilev, LT
p53 肿瘤抑制因子是细胞应激反应的关键介质。多种应激激活激酶诱导的磷酸化对于 p53 稳定、与转录共激活因子的相互作用以及 p53 靶基因的激活至关重要。然而，遗传学研究表明应激激活的磷酸化对于 p53 激活可能不是必需的。因此，我们使用最近开发的小分子 MDM2 拮抗剂 nutlin-3 研究了 p53 磷酸化在六个关键丝氨酸残基（Ser(6)、Ser(15)、Ser(20)、Ser(37)、Ser(46) 和 Ser(392)）上对 p53 激活的作用。我们在此表明 nutlin 不会诱导 p53 的磷酸化。比较 HCT116 和 RKO 细胞中基因毒性药物阿霉素和依托泊苷诱导的非磷酸化和磷酸化 p53 的活性，发现它们的序列特异性 DNA 结合以及反式激活 p53 靶基因和诱导 p53 依赖性细胞凋亡的能力没有差异。我们得出的结论是，p53 在六个主要丝氨酸位点上的磷酸化并不是 p53 靶基因激活或体内生物反应所必需的。
The p53 tumor suppressor is a key mediator of the cellular response to stress. Phosphorylation induced by multiple stress-activated kinases has been proposed to be essential for p53 stabilization, interaction with transcriptional co-activators, and activation of p53 target genes. However, genetic studies suggest that stress-activated phosphorylation may not be essential for p53 activation. We therefore investigated the role of p53 phosphorylation on six key serine residues (Ser(6), Ser(15), Ser(20), Ser(37), Ser(46), and Ser(392)) for p53 activation using nutlin-3, a recently developed small molecule MDM2 antagonist. We show here that nutlin does not induce the phosphorylation of p53. Comparison of the activity of unphosphorylated and phosphorylated p53 induced by the genotoxic drugs doxorubicin and etoposide in HCT116 and RKO cells revealed no difference in their sequence-specific DNA binding and ability to transactivate p53 target genes and to induce p53-dependent apoptosis. We conclude that p53 phosphorylation on six major serine sites is not required for activation of p53 target genes or biological responses in vivo.