A screen for deubiquitinating enzymes involved in the G2/M checkpoint identifies USP50 as a regulator of HSP90-dependent Wee1 stability
A screen for deubiquitinating enzymes involved in the G2/M checkpoint identifies USP50 as a regulator of HSP90-dependent Wee1 stability
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DOI：
10.4161/cc.9.18.13133
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发表时间：
2010-09-15
期刊：
影响因子：
4.3
通讯作者：
Ducommun, Bernard
中科院分区：
文献类型：
--
作者：
Aressy, Bernadette;Jullien, Denis;Ducommun, Bernard
细胞周期进程的严格调控对DNA损伤反应中基因组完整性的维持至关重要。本研究的目的是鉴定参与G(2)/M检查点调节的新的去泛素化酶（DUBs）。通过使用基于sirna的筛选来识别具有增强cdc25b依赖性G(2)/M检查点绕过的固有能力的dub，我们已经确定了11个候选候选，其无效会损害检查点的严格性。我们随后将注意力集中在其中一种，即以前未表征的USP50。利用与质谱相关的tap标签方法，以及酵母-双杂交筛选，我们确定HSP90是USP50的主要相互作用伙伴。我们还证明，USP50耗竭会导致HSP90客户端Wee1的积累损失，而Wee1是G(2)/M细胞周期阻滞的重要组成部分。最后，我们表明，在DNA损伤剂的反应中，USP50在细胞核中积累。我们提出USP50可能通过hsp90依赖机制来抵消CDC25B有丝分裂诱导活性并阻止Wee1降解，从而在DNA损伤检查点激活后抑制进入有丝分裂。
Tight regulation of cell cycle progression is essential for the maintenance of genomic integrity in response to DNA injury. The aim of this study was to identify new deubiquitinating enzymes (DUBs) involved in the regulation of the G(2)/M checkpoint. By using an siRNA-based screen to identify DUBs with an inherent ability to enhance a CDC25B-dependent G(2)/M checkpoint bypass, we have identified 11 candidates whose invalidation compromises checkpoint stringency. We subsequently focused our attention on one of these, the previously uncharacterized USP50. Using a TAP-tag approach associated to mass spectrometry, in addition to a yeast-two-hybrid screen, we identified HSP90 as a major interacting partner for USP50. We also demonstrate USP50 depletion causes a loss in accumulation of the HSP90 client Wee1, which is an essential component of the G(2)/M cell cycle arrest. Finally, we show that in response to DNA damaging agents, USP50 accumulates in the nucleus. We propose that USP50 may act through a HSP90-dependent mechanism to counteract CDC25B mitotic inducing activity and prevent Wee1 degradation, thereby repressing entry into mitosis following activation of the DNA damage checkpoint.