NEK11 regulates CDC25A degradation and the IR-induced G2/M checkpoint
NEK11 regulates CDC25A degradation and the IR-induced G2/M checkpoint
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DOI：
10.1038/ncb1969
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发表时间：
2009-10-01
影响因子：
21.3
通讯作者：
Helin, Kristian
中科院分区：
文献类型：
--
作者：
Melixetian, Marina;Klein, Ditte Kjaersgaard;Helin, Kristian
DNA损伤诱导的细胞周期检查点在维持基因组稳定性方面具有关键作用（1，2）。检查点的一个关键靶标是CDC 25 A（细胞分裂周期25同源物A）磷酸酶，其对于细胞周期蛋白依赖性激酶的激活和细胞周期进程至关重要（3-5）。为了鉴定参与G2/M检查点的新基因，我们进行了大规模短发夹RNA（shRNA）文库筛选。我们发现，NIMA（从未在有丝分裂基因A）相关激酶11（NEK 11）是DNA损伤诱导的G2/M期阻滞所必需的。NEK 11的消耗防止蛋白酶体依赖性的CDC 25 A降解，无论是在未受干扰的细胞和DNA损伤的细胞。我们发现NEK 11直接磷酸化CDC 25 A上的残基，其磷酸化是β-TrCP（β-transducin repeat-containing protein）介导的多泛素化和CDC 25 A降解所必需的。此外，我们证明了CHK 1（检查点激酶1）通过磷酸化丝氨酸273直接激活NEK 11，表明CHK 1和NEK 11在控制CDC 25 A蛋白水解的单一途径中运作。总之，这些结果表明，NEK 11是执行G2/M检查点的途径的重要组成部分，表明NEK 11中的基因突变可能有助于人类癌症的发展。
DNA damage-induced cell-cycle checkpoints have a critical role in maintaining genomic stability(1,2). A key target of the checkpoints is the CDC25A (cell division cycle 25 homologue A) phosphatase, which is essential for the activation of cyclin-dependent kinases and cell-cycle progression(3-5). To identify new genes involved in the G2/M checkpoint we performed a large-scale short hairpin RNA (shRNA) library screen. We show that NIMA (never in mitosis gene A)-related kinase 11 (NEK11) is required for DNA damage-induced G2/M arrest. Depletion of NEK11 prevents proteasome-dependent degradation of CDC25A, both in unperturbed and DNA-damaged cells. We show that NEK11 directly phosphorylates CDC25A on residues whose phosphorylation is required for beta-TrCP (beta-transducin repeat-containing protein)-mediated polyubiquitylation and degradation of CDC25A. Furthermore, we demonstrate that CHK1 (checkpoint kinase 1) directly activates NEK11 by phosphorylating it on Ser 273, indicating that CHK1 and NEK11 operate in a single pathway that controls proteolysis of CDC25A. Taken together, these results demonstrate that NEK11 is an important component of the pathway enforcing the G2/M checkpoint, suggesting that genetic mutations in NEK11 may contribute to the development of human cancer.