核糖核苷酸还原酶（RR）是参与DNA复制和DNA损伤修复的关键酶，敲除其受p53转录调控的小亚基p53R2的小鼠呈现短寿表型。然而RR是否调控衰老，如何调控衰老尚待探讨。我们前期研究发现，RR两类小亚基都与其DNA损伤修复功能相关，其大亚基相互作用蛋白hTrx1（人硫氧还蛋白）对RR酶活性至关重要，且RR复合物中还存在数个氧化还原蛋白。我们推测，RR相互作用蛋白通过调节RR酶活性而调控DNA复制与修复，进而影响细胞衰老进程。本课题将进一步鉴定RR三个亚基的关键相互作用蛋白，解析这些蛋白对RR在DNA损伤修复过程中酶活性的影响，探讨RR及其相互作用蛋白对细胞衰老的调控作用。本课题将通过蛋白组学、酶学、结构学和细胞生物学等层面技术，研究RR相互作用蛋白对RR酶功能及其参与DNA损伤修复进而对细胞衰老进程的影响，为阐明DNA损伤诱导细胞衰老的分子机制提供新的科学依据。

Ribonucleotide reductase (RR) is one of the key enzymes for DNA replication and repair. p53R2, which is regulated by tumor suppressor p53, is a small subunit of RR. p53R2-/- mice showed growth retardation and early mortality. However, whether or how RR regulates cell senescence still remains unknown. Our previous study found that both R2 and p53R2 (two small subunits of RR) were involved in DNA repair, the direct protein-protein interaction between R1 (RR large subunit) and human thioredoxin1 (hTrx1) regulates RR enzymatic activity, and in addition, other redox proteins were identified in RR complexes. Therefore, we hypothesized that RR interacting proteins regulate DNA replication and repair by regulating the enzymatic activity of RR, thereby affecting the process of cell senescence. In this proposed study, we will further identify RR interacting proteins, study the effects and structural and functional mechanisms of these proteins on RR enzymatic activity, DNA repair and cell senescence. Based on the strategy and technology of proteomics, enzymology, structural and cellular biology, this study will contribute to further understand the role and mechanisms of RR subunits and their key regulatory proteins in DNA damage-induced cell senescence.