Protein arginine methylation in nuclear organization, function, and stress response

翻译后修饰扩大了给定基因组的表型范围，从而增加了细胞和生物体的适应性。蛋白质精氨酸甲基转移酶（PRMT）修饰精氨酸残基以调节转录、剪接、翻译和基因组完整性;细胞中超过4000种精氨酸甲基化蛋白质赋予多种功能。最近的进展使识别PRMT底物，然而，我们的知识的效应，下游识别，和功能的甲基精氨酸仍然有限。大多数甲基精氨酸修饰蛋白定位于细胞核、细胞质中，并且一些在毒性刺激后的应激颗粒中发现。PRMT酶本身存在于几乎所有的细胞区室中。虽然大量的文献存在精氨酸甲基化在细胞质和应激颗粒中的作用，但对甲基精氨酸在细胞核中的分布和动力学知之甚少，大多数精氨酸甲基化的蛋白质驻留在细胞核中。我们将使用共聚焦和超分辨率显微镜研究精氨酸甲基化的核结构及其在应激反应中的动力学。我们的初步数据表明，在依赖于蛋白质-蛋白质和蛋白质-RNA相互作用的离散核结构中，甲基精氨酸的丰度很高。精氨酸残基在蛋白质-蛋白质和蛋白质-RNA相互作用中起关键作用;因此，精氨酸的甲基化可以显著影响建立在这些相互作用上的细胞结构。我们将使用选择性抑制剂来调节PRMT酶活性，以确定精氨酸甲基化如何影响这种模型中的分子相互作用力，应激反应核结构如paraspeckles。为了实现这一目标，我们将采用现代方法来评估蛋白质-蛋白质和蛋白质-RNA相互作用的选择性隔间，以及确定新的甲基精氨酸识别模块。我们的研究将提供深入了解精氨酸甲基化的分子机制，其动力学的调节，以及其在应激反应的核生物学中的作用。最后，在我们的研究计划中，学员将在多学科环境中获得显微镜，生物化学，分子和细胞生物学学习的各种技能，使他们能够在未来的职业生涯中取得成功，并为加拿大的知识经济做出贡献。

Post-translational modifications expand the phenotype range of a given genome, thus increasing cellular and organismal adaptability. Protein arginine methyltransferases (PRMT) modify arginine residues to regulate transcription, splicing, translation, and genome integrity; diverse functions conferred by over 4000 arginine methylated proteins in cells. Recent progress enabled the identification of PRMT substrates; however, our knowledge of the effectors, downstream recognition, and function of methyl-arginine remains limited. Most methyl-arginine modified proteins localize in the nucleus, cytoplasm, and some are found in stress granules upon toxic stimuli. PRMT enzymes themselves are found in almost all cellular compartments. While a large body of literature exists on the role of arginine methylation in the cytoplasm and stress granules, little is known about the distribution and dynamics of methyl-arginine in the nucleus, where most arginine methylated proteins reside. We will investigate the nuclear architecture of arginine methylation and its dynamics in stress response using confocal and super-resolution microscopy. Our preliminary data indicates a high abundance of methyl-arginine in discrete nuclear structures that rely on protein-protein and protein-RNA interactions. Arginine residues play critical roles in the protein-protein and protein-RNA interactions; thus, methylation of arginines can dramatically affect the cellular structures built on these interactions. We will modulate the PRMT enzyme activity using selective inhibitors to determine how arginine methylation influences the molecular interaction forces in such model, stress-responsive nuclear structures as paraspeckles. To achieve this, we will employ modern methods to assess protein-protein and protein-RNA interactions in selective compartments as well as identify novel methyl-arginine recognition modules. Our research will provide insights into the molecular mechanism of arginine methylation, the regulation of its dynamics, and its role in the nuclear biology of the stress response. Finally, in our research program, trainees will acquire a diverse set of skills in microscopy, biochemistry, molecular, and cell biology learning in a multidisciplinary environment that will enable them to succeed in their future careers and contribute to Canada's knowledge-based economy.