Nek1 kinase functions in DNA damage response and checkpoint control through a pathway independent of ATM and ATR
Nek1 kinase functions in DNA damage response and checkpoint control through a pathway independent of ATM and ATR
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DOI：
10.4161/cc.10.4.14814
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发表时间：
2011-02-15
期刊：
影响因子：
4.3
通讯作者：
Chen, Phang-Lang
中科院分区：
文献类型：
--
作者：
Chen, Yumay;Chen, Chi-Fen;Chen, Phang-Lang
永不进入有丝分裂相关蛋白激酶1（Nek1）在DNA损伤感知/修复通路的早期发挥作用。我们先前已表明，缺乏功能性Nek1的细胞无法激活更下游的激酶Chk1和Chk2，并且在应对DNA损伤时无法在G₁/S或M期检查点正确停滞。结果，Nek1缺失细胞中受损DNA的聚集在引发损伤后很长时间仍然存在，并且Nek1缺失细胞产生不稳定染色体的比率远高于相同培养条件下的野生型细胞。在此我们表明，Nek1的功能独立于需要磷脂酰肌醇3激酶样蛋白ATM和ATR的经典DNA损伤应答。ATM/ATR的化学抑制剂或编码它们的基因突变无法改变Nek1的激酶活性或其在DNA损伤核聚集中的定位。此外，在Nek1（-/-）小鼠细胞以及通过小干扰RNA沉默Nek1表达的人类细胞中，ATM和ATR的活性，包括蛋白质在DNA损伤位点的定位以及早期DNA损伤应答底物的磷酸化，都是完整的。我们的结果证明Nek1对于适当的检查点控制很重要，并首次描述了一种不直接涉及已知上游介导激酶ATM或ATR的DNA损伤应答。
Never-in-mitosis A related protein kinase 1 (Nek1) is involved early in a DNA damage sensing/repair pathway. We have previously shown that cells without functional Nek1 fail to activate the more distal kinases Chk1 and Chk2 and fail to arrest properly at G(1)/S or M-phase checkpoints in response to DNA damage. As a consequence, foci of damaged DNA in Nek1 null cells persist long after the instigating insult, and Nek1 null cells develop unstable chromosomes at a rate much higher than identically cultured wild-type cells. Here we show that Nek1 functions independently of canonical DNA damage responses requiring the PI3 kinase-like proteins ATM and ATR. Chemical inhibitors of ATM/ATR or mutation of the genes that encode them fail to alter the kinase activity of Nek1 or its localization to nuclear foci of DNA damage. Moreover ATM and ATR activities, including the localization of the proteins to DNA damage sites and phosphorylation of early DNA damage response substrates, are intact in Nek1(-/-) murine cells and in human cells with Nek1 expression silenced by siRNA. Our results demonstrate that Nek1 is important for proper checkpoint control and characterize for the first time a DNA damage response that does not directly involve one of the known upstream mediator kinases, ATM or ATR.