RNF168-mediated H2A neddylation antagonizes ubiquitylation of H2A and regulates DNA damage repair
RNF168-mediated H2A neddylation antagonizes ubiquitylation of H2A and regulates DNA damage repair
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DOI：
10.1242/jcs.138891
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发表时间：
2014-05-15
影响因子：
4
通讯作者：
Zheng, Xiaofeng
中科院分区：
文献类型：
--
作者：
Li, Tingting;Guan, Junhong;Zheng, Xiaofeng
NEDD8在许多生物过程中是一个重要的调控因子。然而，泛素化的底物以及泛素和NEDD8途径之间的关系在很大程度上仍然未知。在这里，我们发现NEDD8与组蛋白2A （H2A）共价结合，并且H2A的类甲化可以拮抗其泛素化。NEDD8抑制H2A的泛素化，降低游离NEDD8水平促进H2A泛素化。此外，我们发现E3连接酶RNF168促进H2A泛素化和类化修饰。有趣的是，RNF168本身是NEDD8的底物，而RNF168的类化修饰对于其E3泛素活性是必要的。抑制RNF168类泛素化会损害RNF168与其E2酶Ubc13（也称为UBE2N）之间的相互作用。此外，在DNA损伤的反应中，H2A泛素化水平降低，H2A泛素化水平升高，有利于DNA损伤的修复。在损伤修复的后期阶段，H2A类泛素化逐渐增加，而泛素化则降至基础水平。从机制上来说，NEDD8通过抑制H2A和γ H2AX的泛素化来负性调节DNA损伤修复过程，从而进一步阻断损伤反应蛋白BRCA1的募集。我们的研究结果阐明了H2A泛素化与类化修饰的关系，并提出了一种通过类化修饰途径介导DNA损伤修复的新途径。
NEDD8 is an important regulatory factor in many biological processes. However, the substrates for neddylation, and the relationship between the ubiquitin and NEDD8 pathways remain largely unknown. Here, we show that NEDD8 is covalently conjugated to histone 2A (H2A), and that neddylation of H2A antagonizes its ubiquitylation. NEDD8 suppresses ubiquitylation of H2A, and a decreased level of free NEDD8 promotes H2A ubiquitylation. Furthermore, we found that the E3 ligase RNF168 promotes both H2A ubiquitylation and neddylation. Interestingly, RNF168 is itself a substrate for NEDD8, and neddylation of RNF168 is necessary for its E3 ubiquitin activity. Inhibition of RNF168 neddylation impairs the interaction between RNF168 and its E2 enzyme Ubc13 (also known as UBE2N). Moreover, in response to DNA damage, the level of H2A neddylation decreased with an increase in the ubiquitylation of H2A, which facilitates DNA damage repair. During the later stages of damage repair, H2A neddylation increased gradually, whereas ubiquitylation decreased to basal levels. Mechanistically, NEDD8 negatively regulates the DNA damage repair process through suppression of the ubiquitylation of H2A and gamma H2AX, which further blocks the recruitment of the damage response protein BRCA1. Our findings elucidate the relationship of H2A ubiquitylation and neddylation, and suggest a novel modulatory approach to DNA damage repair through the neddylation pathway.