TopBP1 activates ATR through ATRIP and a PIKK regulatory domain
TopBP1 activates ATR through ATRIP and a PIKK regulatory domain
复制标题
DOI：
10.1101/gad.1666208
复制
发表时间：
2008-06-01
影响因子：
10.5
通讯作者：
Cortez, David
中科院分区：
文献类型：
--
作者：
Mordes, Daniel A.;Glick, Gloria G.;Cortez, David
ATR(ATM和RAD3相关)激酶及其调节伙伴ARIP(ATR相互作用蛋白)协调对DNA损伤和复制应激的检查点反应。TopBP1是ATR的通用激活剂。然而，TopBP1激活ATR的机制尚不清楚。在这里，我们发现ATIP包含一个TopBP1相互作用区，对于TopBP1和ATR的结合，对于TopBP1介导的ATR的激活，以及细胞在复制应激后存活和恢复DNA合成是必要的。我们证明了该区域在酿酒酵母Ddc2中功能保守，暗示了一种保守的调控机制。此外，我们还确定了ATR的一个结构域，它对TopBP1的激活至关重要。ATR-PRD(Pikk[磷酸肌醇3-激酶相关激酶]调节域)突变不会影响ATR的基础激酶活性，但会阻止其激活。细胞互补实验表明，TopBP1介导的ATR激活是检查点信号和细胞存活所必需的。ATM和mTOR(哺乳动物雷帕霉素靶标)的PRD对这些激酶的活性有调节作用，我们的研究结果表明DNA-PKcs(DNA依赖蛋白激酶催化亚单位)PRD对DNA-PKcs的调节很重要。因此，PRD内不同的氨基酸序列和一个独特的蛋白质伙伴允许这些PIK激酶中的每一个对不同的细胞事件做出反应。
The ATR (ATM and Rad3-related) kinase and its regulatory partner ATRIP (ATR-interacting protein) coordinate checkpoint responses to DNA damage and replication stress. TopBP1 functions as a general activator of ATR. However, the mechanism by which TopBP1 activates ATR is unknown. Here, we show that ATRIP contains a TopBP1-interacting region that is necessary for the association of TopBP1 and ATR, for TopBP1-mediated activation of ATR, and for cells to survive and recover DNA synthesis following replication stress. We demonstrate that this region is functionally conserved in the Saccharomyces cerevisiae ATRIP ortholog Ddc2, suggesting a conserved mechanism of regulation. In addition, we identify a domain of ATR that is critical for its activation by TopBP1. Mutations of the ATR PRD (PIKK [phosphoinositide 3-kinase related kinase] Regulatory Domain) do not affect the basal kinase activity of ATR but prevent its activation. Cellular complementation experiments demonstrate that TopBP1-mediated ATR activation is required for checkpoint signaling and cellular viability. The PRDs of ATM and mTOR (mammalian target of rapamycin) were shown previously to regulate the activities of these kinases, and our data indicate that the DNA-PKcs (DNA-dependent protein kinase catalytic subunit) PRD is important for DNA-PKcs regulation. Therefore, divergent amino acid sequences within the PRD and a unique protein partner allow each of these PIK kinases to respond to distinct cellular events.