Rad3-dependent phosphorylation of the checkpoint clamp regulates repair-pathway choice
Rad3-dependent phosphorylation of the checkpoint clamp regulates repair-pathway choice
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DOI：
10.1038/ncb1600
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发表时间：
2007-06-01
影响因子：
21.3
通讯作者：
Wang, Teresa S. F.
中科院分区：
文献类型：
--
作者：
Kai, Mihoko;Furuya, Kanji;Wang, Teresa S. F.
当复制叉崩溃时，Rad3以依赖于Thr 225（PCNA样结构域内的残基）的方式磷酸化检查点钳蛋白Rad9。然而，Thr 225依赖性Rad9磷酸化的生理功能仍然难以捉摸。在这里，我们表明，Thr 225依赖的Rad9磷酸化Rad3调节DNA修复途径。rad9T225C突变体诱导跨损伤合成（TLS）依赖性高自发突变率和超重组表型。与此一致，Rad9与复制后修复蛋白Mms2共沉淀。这种相互作用依赖于Rad9 Thr 225，并通过DNA损伤而增强。遗传分析表明，Thr 225依赖性Rad9磷酸化防止不适当的Rhp51依赖性重组，可能是通过将修复通过Pli1介导的类小泛素化途径重定向到Rhp6修复途径的无错误分支。我们的研究结果揭示了一种新的机制，通过这种机制，Rad9在Thr 225的磷酸化调节修复途径的选择，以维持细胞周期中基因组的完整性。
When replication forks collapse, Rad3 phosphorylates the checkpoint-clamp protein Rad9 in a manner that depends on Thr 225, a residue within the PCNA-like domain. The physiological function of Thr 225-dependent Rad9 phosphorylation, however, remains elusive. Here, we show that Thr 225-dependent Rad9 phosphorylation by Rad3 regulates DNA repair pathways. A rad9T225C mutant induces a translesion synthesis (TLS)-dependent high spontaneous mutation rate and a hyper-recombination phenotype. Consistent with this, Rad9 coprecipitates with the post-replication repair protein Mms2. This interaction is dependent on Rad9 Thr 225 and is enhanced by DNA damage. Genetic analyses indicate that Thr 225-dependent Rad9 phosphorylation prevents inappropriate Rhp51-dependent recombination, potentially by redirecting the repair through a Pli1-mediated sumoylation pathway into the error-free branch of the Rhp6 repair pathway. Our findings reveal a new mechanism by which phosphorylation of Rad9 at Thr 225 regulates the choice of repair pathways for maintaining genomic integrity during the cell cycle.