DNA-dependent protein kinase and checkpoint kinase 2 synergistically activate a latent population of p53 upon DNA damage
DNA-dependent protein kinase and checkpoint kinase 2 synergistically activate a latent population of p53 upon DNA damage
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DOI：
10.1074/jbc.m309917200
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发表时间：
2004-04-09
影响因子：
4.8
通讯作者：
Lee, PWK
中科院分区：
文献类型：
--
作者：
Jack, MT;Woo, RA;Lee, PWK
检查点激酶2（Chk 2）作为DNA损伤后p53上游激活剂的作用一直存在争议。我们最近发现Chk 2和DNA依赖性蛋白激酶（DNA-PK）都参与了小鼠胚胎成纤维细胞DNA损伤诱导的凋亡，但不参与G（1）阻滞。在这里，我们证明，Chk 2是需要在体外激活p53的能力，其结合的共识DNA靶序列的DNA损伤后，实际上是以前未确定的因素协同作用与DNA-PK激活p53。共济失调毛细血管扩张症中突变的基因不参与这种p53激活。使用渥曼青霉素，p53的丝氨酸15突变体，DNA-PK空细胞和Chk 2空细胞，我们证明，DNA-PK和Chk 2作用于p53独立和顺序。此外，这两种激酶的p53靶标代表了潜在的（预先存在的）p53群体。总之，这些研究的结果与DNA损伤导致DNA-PK和Chk 2对潜伏性p53的立即和连续修饰的模型一致，这在适当条件下可导致细胞凋亡。
The role of the checkpoint kinase 2 (Chk2) as an upstream activator of p53 following DNA damage has been controversial. We have recently shown that Chk2 and the DNA-dependent protein kinase (DNA-PK) are both involved in DNA damage-induced apoptosis but not G(1) arrest in mouse embryo fibroblasts. Here we demonstrate that Chk2 is required to activate p53 in vitro as measured by its ability to bind its consensus DNA target sequence following DNA damage and is in fact the previously unidentified factor working synergistically with DNA-PK to activate p53. The gene mutated in ataxia telangiectasia is not involved in this p53 activation. Using wortmannin, serine 15 mutants of p53, DNA-PK null cells and Chk2 null cells, we demonstrate that DNA-PK and Chk2 act independently and sequentially on p53. Furthermore, the p53 target of these two kinases represents a latent (preexisting) population of p53. Taken together, the results from these studies are consistent with a model in which DNA damage causes an immediate and sequential modification of latent p53 by DNA-PK and Chk2, which under appropriate conditions can lead to apoptosis.