Dynamics of Arginine Methylation in Cellular Processes

精氨酸是构成蛋白质的20种氨基酸中的一种，它表现出一种有趣的化学性质，即在几个原子上携带正电荷，这使得它能够在细胞中形成独特而重要的蛋白质相互作用。一种叫做蛋白质精氨酸n -甲基转移酶（PRMTs）的酶在氨基酸带正电的部分将甲基添加到精氨酸上，从而引起蛋白质功能的变化。这种精氨酸甲基化主要存在于染色质相关蛋白和RNA结合蛋白中，已被证明在基因表达、DNA损伤修复、RNA代谢和转运以及信号转导中发挥调节作用。虽然有几种PRMTs参与这些过程，但其他PRMTs及其底物的功能作用尚不明确。在我们的研究计划中，我们有两个目标来解决这一知识差距。首先，我们利用蛋白质组学方法确定了参与RNA剪接调节程序性细胞死亡的PRMT2相互作用伙伴，我们计划通过增加或减少其表达和测量剪接RNA及其相互作用的变化来确定PRMT2如何在细胞中促进这一过程。其次，我们使用蛋白质组学测量了炎症应激处理细胞中精氨酸甲基化的整体变化，以发现反应性蛋白网络和重要的PRMT底物。根据这些结果，我们计划确定炎症期间NF-kappaB信号中观察到的底物甲基化增加的重要性，以及其他甲基化事件的后果。我们还希望利用这种蛋白质组学方法来发现细胞对基因毒性和缺氧应激的反应，以此来揭示几种不同类型细胞应激之间精氨酸甲基化网络的独特和共同特征。总的来说，这项工作将为PRMT活动的整合如何促进细胞编程并最终决定细胞命运提供机制见解，这将在生命科学研究的多个领域产生广泛影响。受NSERC资助的学员将在一个研究密集型的环境中学习生物化学和细胞生物学的各种尖端技能，这将有助于他们在拟议的工作和未来的科学事业中取得成功。

Arginine, one of the twenty amino acid building blocks that make up proteins, exhibits the interesting chemical property of bearing a positive charge spread over several atoms that allows it to form unique and important interactions for proteins in cells. Enzymes called protein arginine N-methyltransferases (PRMTs) adds methyl groups onto arginines within the positively charged part of the amino acid to elicit changes in protein function. This arginine methylation, found predominantly in chromatin-associated and RNA-binding proteins, has been shown to play regulatory roles in gene expression, DNA damage repair, RNA metabolism and transport, and signal transduction. Whereas several PRMTs participate in these processes, the functional role other PRMTs and their substrates is less well defined. We address this gap in our knowledge with two aims in our research proposal. First, we have identified using proteomics PRMT2 interacting partners involved in RNA splicing that regulates programmed cell death, and we plan to determine how PRMT2 contributes to this process in cells by increasing or decreasing its expression and measuring changes to spliced RNA and its interactions. Second, we have measured using proteomics global changes to arginine methylation in cells treated with inflammatory stress in an effort to discover responsive protein networks and important PRMT substrates. Following up on these results, we plan to determine the importance of increased substrate methylation observed in NF-kappaB signaling during inflammation, as well as the consequences of other methylation events. We would also like to take advantage of this proteomic method for discovery to look at cell responses to genotoxic and hypoxic stresses as a way to reveal unique and common features within arginine methylation networks between several different types of cell stress. Overall, this work will provide mechanistic insight into how the integration of PRMT activities contributes to cellular programming and ultimately determines cell fate, which will have broad impact in multiple fields of life science research. Trainees supported by this NSERC grant will learn a diverse set of cutting-edge skills in biochemistry and cell biology offered in a research-intensive environment that will help them to succeed in the proposed work and their future scientific careers.