SCFβTrCP-mediated degradation of claspin regulates recovery from the DNA replication checkpoint response
SCFβTrCP-mediated degradation of claspin regulates recovery from the DNA replication checkpoint response
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DOI：
10.1016/j.molcel.2006.06.013
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发表时间：
2006-08-04
期刊：
影响因子：
16
通讯作者：
Pagano, Michele
中科院分区：
文献类型：
--
作者：
Peschiaroli, Angelo;Dorrello, N. Valerio;Pagano, Michele
在复制应激过程中，Claspin介导ATR对Chk1的磷酸化和随后的激活。我们发现，在从DNA复制检查点响应恢复期间，Claspin以β TrCP依赖性方式降解。在体内，Claspin在典型的DSGxxS降解决定子序列中被磷酸化，这是β TrCP底物的典型序列。Claspin的磷酸化由PIK1介导，并且对于与β TrCP结合是必需的。Claspin的体外泛素化需要β TrCP、PIK1和完整的DSGxxS降解决定子。值得注意的是，不能结合β TrCP的稳定Claspin突变体的表达抑制了Chk1的激活，从而减弱了从DNA复制应激反应中的恢复，并显著延迟了进入有丝分裂。因此，Claspin的SCF β TrCP依赖性降解对于DNA复制检查点的有效和及时终止是必要的。重要的是，响应于G2中的DNA损伤，Claspin蛋白水解被抑制以允许检查点的迅速重建。
During replicative stress, Claspin mediates the phosphorylation and consequent activation of Chk1 by ATR. We found that during recovery from the DNA replication checkpoint response, Claspin is degraded in a beta TrCP-dependent manner. In vivo, Claspin is phosphorylated in a canonical DSGxxS degron sequence, which is typical of beta TrCP substrates. Phosphorylation of Claspin is mediated by PIk1 and is essential for binding to beta TrCP. In vitro ubiquitylation of Claspin requires beta TrCP, PIk1, and an intact DSGxxS degron. Significantly, expression of a stable Claspin mutant unable to bind beta TrCP prolongs the activation of Chk1, thereby attenuating the recovery from the DNA replication stress response and significantly delaying entry into mitosis. Thus, the SCF beta TrCP-dependent degradation of Claspin is necessary for the efficient and timely termination of the DNA replication checkpoint. Importantly, in response to DNA damage in G2, Claspin proteolysis is inhibited to allow the prompt reestablishment of the checkpoint.