Dynamics of Arginine Methylation in Cellular Processes

精氨酸是组成蛋白质的二十个氨基酸之一，它表现出有趣的化学特性，即携带正电荷分布在几个原子上，使其能够在细胞中与蛋白质形成独特而重要的相互作用。被称为蛋白质精氨酸N-甲基转移酶(PRMTs)的酶将甲基添加到氨基酸的正电部分的精氨酸上，以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代谢和运输以及信号转导中发挥调节作用。尽管有几个PRMT参与了这些过程，但其他PRMT及其底物的功能作用却没有得到很好的定义。我们在我们的研究提案中有两个目标来解决我们知识中的这一差距。首先，我们已经利用蛋白质组学确定了参与调节细胞程序性死亡的RNA剪接的PRMT2相互作用伙伴，我们计划通过增加或减少其表达并测量剪接RNA及其相互作用的变化来确定PRMT2如何在细胞中对这一过程做出贡献。其次，我们使用蛋白质组学测量了在炎症应激处理的细胞中精氨酸甲基化的全球变化，以努力发现响应性蛋白质网络和重要的PRMT底物。根据这些结果，我们计划确定炎症过程中观察到的核因子-kappaB信号中底物甲基化增加的重要性，以及其他甲基化事件的后果。我们还想利用这种蛋白质组学的方法来研究细胞对遗传毒性和低氧应激的反应，以此来揭示几种不同类型的细胞应激之间精氨酸甲基化网络中独特和共同的特征。总体而言，这项工作将提供对PRMT活动的整合如何有助于细胞编程并最终决定细胞命运的机械性见解，这将在生命科学研究的多个领域产生广泛影响。在NSERC拨款的支持下，学员将学习在研究密集型环境中提供的生物化学和细胞生物学方面的各种尖端技能，这将有助于他们在拟议的工作和未来的科学职业生涯中取得成功。**

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.**