Quantitative phosphoproteomics reveals mitotic function of the ATR activator ETAA1
Quantitative phosphoproteomics reveals mitotic function of the ATR activator ETAA1
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DOI：
10.1083/jcb.201810058
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发表时间：
2019-04-01
影响因子：
7.8
通讯作者：
Cortez, David
中科院分区：
文献类型：
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作者：
Bass, Thomas E.;Cortez, David
ATR激酶控制细胞周期转换和DNA损伤反应。ATR活性通过两种ATR激活蛋白ETAA1和TOPBP1调节。为了研究每种激活剂如何促进ATR信号传导，我们使用定量质谱法来鉴定ETAA1或TOPBP1缺陷细胞中蛋白磷酸化的变化。我们确定了724，285，和118个磷酸化位点，分别由TOPBP1，ETAA1，或ATR激活剂。TOPBP1和ETAA1依赖性磷蛋白的基因本体分析揭示TOPBP1是复制应激的主要ATR激活剂，而ETAA1调节有丝分裂ATR信号传导。ATR或ETAA1（而非TOPBP1）的失活导致有丝分裂期间极光B激酶活性降低。此外，ATR激活ETAA1需要在中期正确的染色体排列和一个完整的功能纺锤体组装检查点响应。因此，我们得出结论，ETAA1和TOPBP1调节ATR信号的不同方面，ETAA1在有丝分裂细胞中具有主导功能。
The ATR kinase controls cell cycle transitions and the DNA damage response. ATR activity is regulated through two ATR-activating proteins, ETAA1 and TOPBP1. To examine how each activator contributes to ATR signaling, we used quantitative mass spectrometry to identify changes in protein phosphorylation in ETAA1- or TOPBP1-deficient cells. We identified 724, 285, and 118 phosphosites to be regulated by TOPBP1, ETAA1, or both ATR activators, respectively. Gene ontology analysis of TOPBP1- and ETAA1-dependent phosphoproteins revealed TOPBP1 to be a primary ATR activator for replication stress, while ETAA1 regulates mitotic ATR signaling. Inactivation of ATR or ETAA1, but not TOPBP1, results in decreased Aurora B kinase activity during mitosis. Additionally, ATR activation by ETAA1 is required for proper chromosome alignment during metaphase and for a fully functional spindle assembly checkpoint response. Thus, we conclude that ETAA1 and TOPBP1 regulate distinct aspects of ATR signaling with ETAA1 having a dominant function in mitotic cells.