Extracellular signal-related kinase positively regulates ataxia telangiectasia mutated, homologous recombination repair, and the DNA damage response
Extracellular signal-related kinase positively regulates ataxia telangiectasia mutated, homologous recombination repair, and the DNA damage response
复制标题
DOI：
10.1158/0008-5472.can-06-2371
复制
发表时间：
2007-02-01
期刊：
影响因子：
11.2
通讯作者：
Valerie, Kristoffer
中科院分区：
文献类型：
--
作者：
Golding, Sarah E.;Rosenberg, Elizabeth;Valerie, Kristoffer
DNA双链断裂通过同源重组修复(HRR)的准确连接对细胞的长期生存至关重要。细胞外信号调节蛋白(ERR)、p38和c-Jun-NH2-Kinase(JNK)这三个主要的丝裂原活化蛋白激酶(MAPK)信号转导通路调节细胞的生长、存活和凋亡。为了确定MAPK信号在HRR中的作用，我们使用了一个基于人在体I-SCEI的修复系统。首先，我们验证了这个修复平台是药物操纵的，并表明共济失调毛细血管扩张突变(ATM)激酶在HRR中起着关键作用。ATM特异性抑制剂KU-55933在生长停滞细胞中对HRR的影响高达90%，而在周期细胞中这种影响不那么明显。然后，利用表征良好的MAPK小分子抑制剂，我们证明ERK1/2和JNK信号是生长停滞细胞中HRR的重要正向调节因子。另一方面，抑制p38MAPK通路可产生近2倍的HRR刺激。当ERK1/2信号被致癌的RAF-1刺激时，HRR几乎增加了2倍。KU-55933部分阻断辐射诱导的ERK1/2磷酸化，提示ATM调节ERK1/2信号转导。此外，抑制MAP/ERK激酶(MEK)/ERK信号导致磷酸化(S1981)ATM焦点的水平严重降低，而不是伽马-H2AX焦点的水平，并在整个细胞周期中抑制ATM磷酸化水平>；85%。综上所述，这些结果表明，MAPK信号对人类细胞的HRR有正向和负向调节作用。更具体地说，通过RAF/MEK/ERK通路的ATM依赖信号对于有效的HRR和辐射诱导的ATM激活至关重要，这表明ERK和ATM之间存在调节反馈环。
The accurate joining of DNA double-strand breaks by homologous recombination repair (HRR) is critical to the long-term survival of the cell. The three major mitogen-activated protein (MAP) kinase (MAPK) signaling pathways, extracellular signal-regulated kinase (ERR), p38, and c-Jun-NH2-kinase (JNK), regulate cell growth, survival, and apoptosis. To determine the role of MAPK signaling in HRR, we used a human in vivo I-SceI-based repair system. First, we verified that this repair platform is amenable to pharmacologic manipulation and show that the ataxia telangiectasia mutated (ATM) kinase is critical for HRR. The ATM-specific inhibitor KU-55933 compromised HRR up to 90% in growth-arrested cells, whereas this effect was less pronounced in cycling cells. Then, using well-characterized MAPK small-molecule inhibitors, we show that ERK1/2 and JNK signaling are important positive regulators of HRR in growth-arrested cells. On the other hand, inhibition of the p38 MAPK pathway generated an almost 2-fold stimulation of HRR. When ERK1/2 signaling was stimulated by oncogenic RAF-1, an similar to 2-fold increase in HRR was observed. KU-55933 partly blocked radiation-induced ERK1/2 phosphorylation, suggesting that ATM regulates ERK1/2 signaling. Furthermore, inhibition of MAP/ERK kinase (MEK)/ERK signaling resulted in severely reduced levels of phosphorylated (S1981) ATM foci but not gamma-H2AX foci, and suppressed ATM phosphorylation levels > 85% throughout the cell cycle. Collectively, these results show that MAPK signaling positively and negatively regulates HRR in human cells. More specifically, ATM-dependent signaling through the RAF/MEK/ERK pathway is critical for efficient HRR and for radiation-induced ATM activation, suggestive of a regulatory feedback loop between ERK and ATM.