The checkpoint clamp activates Mec1 kinase during initiation of the DNA damage checkpoint
The checkpoint clamp activates Mec1 kinase during initiation of the DNA damage checkpoint
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DOI：
10.1016/j.molcel.2006.11.027
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发表时间：
2006-12-28
期刊：
影响因子：
16
通讯作者：
Burgers, Peter M. J.
中科院分区：
文献类型：
--
作者：
Majka, Jerzy;Niedziela-Majka, Anita;Burgers, Peter M. J.
酵母Mec1/Ddc2蛋白激酶是人类ATR/ATRIP的同源物，在DNA损伤检查点中起核心作用。类似pcna的钳位rad17 /Mec3/Ddc1（人的9-1-1复合体）及其装载器Rad24-RFC也是该信号转导通路的重要组成部分。在这里，我们研究了钳子在调节Mec1中的作用，并描述了DNA损伤产生的信号如何被转导到Rad53效应激酶。检查点钳极大地激活Mec1的激酶活性，但只有当钳适当地装载在部分双工DNA上。活化的Mec1磷酸化了clamp的Ddc1和Mec3亚基、loader的Rad24亚基以及RPA的Rpa1和Rpa2亚基。Rad53和人类pase -1（非特异性靶标）的磷酸化也需要适当负载的钳子。磷酸化和与单个clamp亚基的结合研究表明，Ddc1亚基介导与Mec1的功能相互作用。
Yeast Mec1/Ddc2 protein kinase, the ortholog of human ATR/ATRIP, plays a central role in the DNA damage checkpoint. The PCNA-like clamp Radl7/Mec3/Ddc1 (the 9-1-1 complex in human) and its loader Rad24-RFC are also essential components of this signal transduction pathway. Here we have studied the role of the clamp in regulating Mec1, and we delineate how the signal generated by DNA lesions is transduced to the Rad53 effector kinase. The checkpoint clamp greatly activates the kinase activity of Mec1, but only if the clamp is appropriately loaded upon partial duplex DNA. Activated Mec1 phosphorylates the Ddc1 and Mec3 subunits of the clamp, the Rad24 subunit of the loader, and the Rpa1 and Rpa2 subunits of RPA. Phosphorylation of Rad53, and of human PHAS-1, a nonspecific target, also requires a properly loaded clamp. Phosphorylation and binding studies with individual clamp subunits indicate that the Ddc1 subunit mediates the functional interactions with Mec1.