Stability and sub-cellular localization of DNA polymerase β is regulated by interactions with NQO1 and XRCC1 in response to oxidative stress
Stability and sub-cellular localization of DNA polymerase β is regulated by interactions with NQO1 and XRCC1 in response to oxidative stress
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DOI：
10.1093/nar/gkz293
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发表时间：
2019-07-09
影响因子：
14.9
通讯作者：
Sobol, Robert W.
中科院分区：
文献类型：
--
作者：
Fang, Qingming;Andrews, Joel;Sobol, Robert W.
蛋白质之间的相互作用调节细胞中许多基本的酶促过程。因此，酶活性位点外的体细胞突变可以通过破坏关键的蛋白质-蛋白质相互作用来影响细胞功能。在我们对DNA聚合酶β (Pol β) T304I癌症突变的细胞影响的研究中，我们发现这种表面苏氨酸残基的突变影响了关键的Pol β蛋白-蛋白质相互作用。我们发现蛋白酶体介导的Pol β降解通过独特的蛋白质-蛋白质相互作用受到泛素依赖性和泛素非依赖性过程的调节。泛素非依赖性蛋白酶体途径通过Pol β与NAD(P)H醌脱氢酶1 （NQO1）相互作用，以nadh依赖的方式调节胞浆中Pol β的稳定性。相反，Pol β与支架蛋白x射线修复交叉互补1 （XRCC1）的相互作用在Pol β定位到核室中发挥作用，并通过泛素依赖途径调节Pol β的稳定性。此外，我们发现氧化应激促进了Pol β /NQO1复合物的解离，增强了Pol β与XRCC1的相互作用。我们的研究结果表明，体细胞突变（如Pol β中的T304I）会影响关键的蛋白质-蛋白质相互作用，改变Pol β的稳定性和亚细胞定位，并为关键蛋白质-蛋白质相互作用如何调节细胞对应激的反应提供机制见解。
Protein-protein interactions regulate many essential enzymatic processes in the cell. Somatic mutations outside of an enzyme active site can therefore impact cellular function by disruption of critical protein-protein interactions. In our investigation of the cellular impact of the T304I cancer mutation of DNA Polymerase beta (Pol beta), we find that mutation of this surface threonine residue impacts critical Pol beta protein-protein interactions. We show that proteasome-mediated degradation of Pol beta is regulated by both ubiquitin-dependent and ubiquitin-independent processes via unique protein-protein interactions. The ubiquitin-independent proteasome pathway regulates the stability of Pol beta in the cytosol via interaction between Pol beta and NAD(P)H quinone dehydrogenase 1 (NQO1) in an NADH-dependent manner. Conversely, the interaction of Pol beta with the scaffold protein X-ray repair cross complementing 1 (XRCC1) plays a role in the localization of Pol beta to the nuclear compartment and regulates the stability of Pol beta via a ubiquitin-dependent pathway. Further, we find that oxidative stress promotes the dissociation of the Pol beta/NQO1 complex, enhancing the interaction of Pol beta with XRCC1. Our results reveal that somatic mutations such as T304I in Pol beta impact critical protein-protein interactions, altering the stability and sub-cellular localization of Pol beta and providing mechanistic insight into how key protein-protein interactions regulate cellular responses to stress.