Rad17 plays a central role in establishment of the interaction between TopBP1 and the Rad9-Hus1-Rad1 complex at stalled replication forks.
Rad17 plays a central role in establishment of the interaction between TopBP1 and the Rad9-Hus1-Rad1 complex at stalled replication forks.
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DOI：
10.1091/mbc.e09-11-0958
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发表时间：
2010-03-15
影响因子：
3.3
通讯作者：
Dunphy WG
中科院分区：
文献类型：
--
作者：
Lee J;Dunphy WG
这项工作为TopBP1和Rad9-Hus1-Rad1(9-1-1)复合体如何在停滞的复制叉子上彼此对接提供了新的机械见解。在检查点响应期间，这一步骤对于依赖ATR的Chk1的激活是必要的。在检查点反应过程中，RAD17对依赖ATR的Chk1的激活至关重要。已知Rad17将Rad9-Hus1-Rad1(9-1-1)复合体装载到DNA上。我们发现RAD17还介导了9-1-1与非洲爪哇卵提取物中ATR激活蛋白TopBP1的相互作用。对Rad17突变体的研究表明，ATP与Rad17的结合对于9-1-1和TopBP1的结合是必不可少的。此外，Rad17对ATP的水解是将9-1-1加载到DNA上以及TopBP1在染色质上依赖检查点积累所必需的。值得注意的是，不能与TopBP1结合的突变9-1-1复合体有正常的能力促进TopBP1在染色质上的积累。综上所述，我们提出了以下机制。首先，RAD17将9-1-1加载到DNA上。第二，TopBP1在染色质上的积累依赖于Rad17和9-1-1。最后，在Chk1激活之前，9-1-1和TopBP1以Rad17依赖的方式对接。
This work provides novel mechanistic insights into how TopBP1 and the Rad9-Hus1-Rad1 (9-1-1) complex dock with one another at stalled replication forks. This step is necessary for the ATR-dependent activation of Chk1 during checkpoint responses. Rad17 is critical for the ATR-dependent activation of Chk1 during checkpoint responses. It is known that Rad17 loads the Rad9-Hus1-Rad1 (9-1-1) complex onto DNA. We show that Rad17 also mediates the interaction of 9-1-1 with the ATR-activating protein TopBP1 in Xenopus egg extracts. Studies with Rad17 mutants indicate that binding of ATP to Rad17 is essential for the association of 9-1-1 and TopBP1. Furthermore, hydrolysis of ATP by Rad17 is necessary for the loading of 9-1-1 onto DNA and the elevated, checkpoint-dependent accumulation of TopBP1 on chromatin. Significantly, a mutant 9-1-1 complex that cannot bind TopBP1 has a normal capacity to promote elevated accumulation of TopBP1 on chromatin. Taken together, we propose the following mechanism. First, Rad17 loads 9-1-1 onto DNA. Second, TopBP1 accumulates on chromatin in a manner that depends on both Rad17 and 9-1-1. Finally, 9-1-1 and TopBP1 dock in a Rad17-dependent manner before activation of Chk1.
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影响因子：
3.3
作者：
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通讯作者：
Lindsay, HD
影响因子：
10.5
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作者：
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通讯作者：
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