Kapoor Prabodh, Bao Yunhe, Xiao Jing, Espejo Alexsandra, Yang Lin, Bedford Mark T, Peng Guang, Shen Xuetong
Department of Epigenetics and Molecular Carcinogenesis, Science Park Research Division, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Mol Cell. 2015 Jun 4;58(5):863-9. doi: 10.1016/j.molcel.2015.03.032. Epub 2015 May 7.
ATP-dependent chromatin remodeling complexes such as INO80 have been implicated in checkpoint regulation in response to DNA damage. However, how chromatin remodeling complexes regulate DNA damage checkpoints remain unclear. Here, we identified a mechanism of regulating checkpoint effector kinase Rad53 through a direct interaction with the INO80 chromatin remodeling complex. Rad53 is a key checkpoint kinase downstream of Mec1. Mec1/Tel1 phosphorylates the Ies4 subunit of the INO80 complex in response to DNA damage. We find that the phosphorylated Ies4 binds to the N-terminal FHA domain of Rad53. In vitro, INO80 can activate Rad53 kinase activity in an Ies4-phosphorylation-dependent manner in the absence of known activators such as Rad9. In vivo, Ies4 and Rad9 function synergistically to activate Rad53. These findings establish a direct connection between ATP-dependent chromatin remodeling complexes and checkpoint regulation.
诸如INO80之类的ATP依赖性染色质重塑复合物已被证明参与了对DNA损伤的检查点调控。然而，染色质重塑复合物如何调控DNA损伤检查点仍不清楚。在此，我们确定了一种通过与INO80染色质重塑复合物直接相互作用来调控检查点效应激酶Rad53的机制。Rad53是Mec1下游的关键检查点激酶。Mec1/Tel1在DNA损伤时磷酸化INO80复合物的Ies4亚基。我们发现磷酸化的Ies4与Rad53的N端FHA结构域结合。在体外，在没有已知激活剂如Rad9的情况下，INO80可以以Ies4磷酸化依赖的方式激活Rad53激酶活性。在体内，Ies4和Rad9协同作用激活Rad53。这些发现建立了ATP依赖性染色质重塑复合物与检查点调控之间的直接联系。
