TDP1 serine 81 promotes interaction with DNA ligase IIIα and facilitates cell survival following DNA damage
TDP1 serine 81 promotes interaction with DNA ligase IIIα and facilitates cell survival following DNA damage
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DOI：
10.4161/cc.9.3.10598
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发表时间：
2010-02-01
期刊：
影响因子：
4.3
通讯作者：
El-Khamisy, Sherif F.
中科院分区：
文献类型：
--
作者：
Chiang, Shih-Chieh;Carroll, Jean;El-Khamisy, Sherif F.
酪氨酰 DNA 磷酸二酯酶 (TDP1) 是一种 DNA 3' 端加工酶，优先水解 DNA 3' 端与停滞的 DNA 拓扑异构酶 1 之间的键。TDP1 的重要性因其与人类遗传病脊髓小脑共济失调伴轴突神经病的关联而凸显。 TDP1 由高度保守的 C 端磷酸二酯酶结构域和不太保守的 N 端尾部组成。 N 末端结构域与 Lig3 α 的相互作用表明了其重要性。在这里，我们表明这种相互作用是由位于 TDP1 N 末端结构域的推定 S/TQ 位点内的丝氨酸 81 促进的。尽管丝氨酸81突变为丙氨酸对体外TDP1活性没有影响，并且对体内TDP1介导CPT或IR诱导的DNA断裂快速修复的能力影响不大，但它导致蛋白质稳定性显着降低。此外，它还降低了 TDP1 在基因毒性应激后促进细胞存活的能力。总之，我们的研究结果强调了哺乳动物细胞中调节 TDP1 功能的新机制，该机制与其酶活性不直接相关。
Tyrosyl DNA phosphodiesterase (TDP1) is a DNA 3'-end processing enzyme that preferentially hydrolyses the bond between the 3'-end of DNA and stalled DNA topoisomerase 1. The importance of TDP1 is highlighted by its association with the human genetic disease spinocerebellar ataxia with axonal neuropathy. TDP1 comprises of a highly conserved C-terminus phosphodiesterase domain and a less conserved N-terminus tail. The importance of the N-terminus domain was suggested by its interaction with Lig3 alpha. Here we show that this interaction is promoted by serine 81 that is located within a putative S/TQ site in the N-terminus domain of TDP1. Although mutation of serine 81 to alanine had no impact on TDP1 activity in vitro and had little impact on the ability of TDP1 to mediate the rapid repair of CPT- or IR-induced DNA breaks in vivo, it led to marked reduction of protein stability. Moreover, it reduced the ability of TDP1 to promote cell survival following genotoxic stress. Together, our findings highlight a novel mechanism for regulating TDP1 function in mammalian cells that is not directly related to its enzymatic activity.