Distinct roles for DNA-PK, ATM and ATR in RPA phosphorylation and checkpoint activation in response to replication stress.
Distinct roles for DNA-PK, ATM and ATR in RPA phosphorylation and checkpoint activation in response to replication stress.
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DOI：
10.1093/nar/gks849
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发表时间：
2012-11
影响因子：
14.9
通讯作者：
Oakley GG
中科院分区：
文献类型：
--
作者：
Liu S;Opiyo SO;Manthey K;Glanzer JG;Ashley AK;Amerin C;Troksa K;Shrivastav M;Nickoloff JA;Oakley GG
DNA 复制叉遇到的 DNA 损伤会带来基因组不稳定的风险，这是致癌的前兆。当损伤严重时，损伤检查点系统会导致细胞周期停滞，促进修复并诱导程序性细胞死亡。检查点是 DNA 损伤反应网络的关键部分，可抑制癌症。 DNA 损伤和复制机制的扰动会导致复制应激，其特征是复制蛋白 A (RPA) 结合的单链 DNA 积累，从而触发共济失调性毛细血管扩张和 Rad3 相关 (ATR) 的激活以及 RPA32（RPA 亚基）的磷酸化，从而导致 Chk1 激活和停滞。 DNA 依赖性蛋白激酶催化亚基 (DNA-PKcs) [一种与共济失调毛细血管扩张突变 (ATM) 和 ATR 相关的激酶] 在 DNA 双链断裂修复中具有明确的作用，但在复制应激诱导的 RPA 磷酸化中的作用却知之甚少。我们发现，DNA-PKcs 突变细胞在应激后无法阻止复制，并且 DNA-PKcs 靶向的 RPA32 磷酸化位点的突变增加了细胞有丝分裂的比例，损害了 Chk1 的 ATR 信号传导并导致 G2/M 停滞缺陷。 ATR 和 DNA-PK（但不是 ATM）的抑制，模拟在表达突变 RPA32 的细胞中观察到的缺陷。表达突变 RPA32 或 DNA-PKcs 的细胞表现出持续的 H2AX 磷酸化，以响应进入有丝分裂的细胞中持续存在的复制应激，表明不适当的有丝分裂进入和未修复的损伤。
DNA damage encountered by DNA replication forks poses risks of genome destabilization, a precursor to carcinogenesis. Damage checkpoint systems cause cell cycle arrest, promote repair and induce programed cell death when damage is severe. Checkpoints are critical parts of the DNA damage response network that act to suppress cancer. DNA damage and perturbation of replication machinery causes replication stress, characterized by accumulation of single-stranded DNA bound by replication protein A (RPA), which triggers activation of ataxia telangiectasia and Rad3 related (ATR) and phosphorylation of the RPA32, subunit of RPA, leading to Chk1 activation and arrest. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) [a kinase related to ataxia telangiectasia mutated (ATM) and ATR] has well characterized roles in DNA double-strand break repair, but poorly understood roles in replication stress-induced RPA phosphorylation. We show that DNA-PKcs mutant cells fail to arrest replication following stress, and mutations in RPA32 phosphorylation sites targeted by DNA-PKcs increase the proportion of cells in mitosis, impair ATR signaling to Chk1 and confer a G2/M arrest defect. Inhibition of ATR and DNA-PK (but not ATM), mimic the defects observed in cells expressing mutant RPA32. Cells expressing mutant RPA32 or DNA-PKcs show sustained H2AX phosphorylation in response to replication stress that persists in cells entering mitosis, indicating inappropriate mitotic entry with unrepaired damage.
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影响因子：
4.3
作者：
Anantha, Rachel William;Borowiec, James A.
通讯作者：
Borowiec, James A.
DOI：
10.1073/pnas.052545899
发表时间：
2002-03-19
影响因子：
11.1
作者：
Allen, C;Kurimasa, A;Nickoloff, JA
通讯作者：
Nickoloff, JA
影响因子：
3.3
作者：
Gately, DP;Hittle, JC;Yen, TJ
通讯作者：
Yen, TJ
DOI：
10.1073/pnas.95.2.525
发表时间：
1998-01-20
影响因子：
11.1
作者：
Hammarsten, O;Chu, G
通讯作者：
Chu, G
影响因子：
3.4
作者：
Cromheecke, M;Piers, BA;Hoekstra, HJ
通讯作者：
Hoekstra, HJ