Mechanisms of Translation Regulation During Stress

摘要 蛋白质组的动态调节对细胞的生存和功能至关重要。传统上，研究人员已经 侧重于阐明蛋白质合成、质量控制和降解的离散步骤，以了解 蛋白质组是如何形成和维持的。然而，越来越多的研究表明，交流 翻译、质量控制和蛋白质降解途径之间的关系使细胞能够维持蛋白质 动态平衡(蛋白质平衡)。蛋白质平衡崩溃是衰老和衰老相关的标志 神经退行性疾病和蛋白平衡基因的等位基因与广泛的人类 遗传病。因此，了解蛋白质平衡背后的机制有望为 确定新的诊断和治疗干预策略，以改善整个生命周期的健康。 我的研究计划将解决蛋白质质量控制因素如何相互作用和反馈调节 翻译。我们的首要目标是确定蛋白质降解因子 与翻译机器合作合成蛋白质。我们假设动态监管 需要蛋白质质量控制和降解活动来防止灾难性的 蛋白抑制剂崩溃。这一假说得到了以下观察的支持：抑制泛素- 蛋白酶体系统的反馈作用是(I)抑制全球翻译活性，(Ii)损害RNA的动力学-- 蛋白质(RNP)颗粒，隔离翻译抑制的mRNAs。在接下来的五年里，我的研究 小组将评估蛋白质质量控制和降解因素在调节蛋白质合成中的作用 翻译的起始、延伸以及促进RNP的动态组装和拆卸的水平 颗粒。为了解决这个问题，我们将回答以下问题：(1)是翻译延伸吗 蛋白质恒定应激过程中的差异调节？(2)蛋白质质量控制机制在 翻译的启动和延伸？(3)翻译与RNP的关系是什么 颗粒？(4)蛋白质质量控制和降解因子的分子机制是什么？ 推动RNP颗粒解体？我们将利用先进的基因组工程、光遗传学和活细胞 成像策略，以确定调节人类细胞中的mRNA翻译的机制 蛋白抑制应激源。这项研究的结果将是一张空间和时间上定义的地图 蛋白应激过程中控制信使核糖核酸翻译的分子机制。这项工作的影响将是 有助于我们了解蛋白质平衡是如何在真核生物中维持的，并识别新的 治疗因蛋白平衡丧失而引起的多种人类疾病的方法。

ABSTRACT The dynamic regulation of the proteome is critical for cell survival and function. Traditionally, researchers have focused on elucidating the discrete steps of protein synthesis, quality control, and degradation to understand how the proteome is formed and maintained. Yet, a growing body of research suggests communication between translation, quality control, and protein degradation pathways enables the cell to maintain protein homeostasis (proteostasis). Proteostasis collapse is a hallmark of aging and aging-associated neurodegenerative diseases, and alleles of proteostasis genes are associated with a wide range of human genetic diseases. Therefore, understanding the mechanisms that underlie proteostasis holds promise for the identification of novel diagnostic and therapeutic intervention strategies to improve health across the lifespan. My research program will address how protein quality control factors interact and feedback to regulate translation. Our overarching goal is to determine the mechanisms by which protein degradation factors collaborate with the translational machinery to synthesize proteins. We hypothesize that the dynamic regulation of mRNA translation requires protein quality control and degradation activities to prevent catastrophic proteostatic collapse. This hypothesis is supported by the observations that inhibition of the ubiquitin- proteasome system feeds back to (i) inhibit global translation activity, and (ii) impairs the dynamics of RNA- protein (RNP) granules that sequester translationally repressed mRNAs. In the next five years, my research group will evaluate the role of protein quality control and degradation factors in mediating protein synthesis at the levels of translation initiation, elongation, and by facilitating the dynamic assembly and disassembly of RNP granules. To begin to address this problem, we will answer the following questions: (1) Is translation elongation differentially regulated during proteostatic stress? (2) What is the role of the protein quality control machinery in mediating translation initiation and elongation? (3) What is the relationship between translation and RNP granules? (4) What are the molecular mechanisms by which protein quality control and degradation factors drive RNP granule disassembly? We will leverage advanced genome engineering, optogenetics, and live cell imaging strategies to define the mechanisms that regulate mRNA translation in human cells in response to proteostatic stressors. The outcome of this research will be a spatially and temporally defined map of the molecular mechanisms governing mRNA translation during proteostatic stress. The impact of this work will be in contributing to our knowledge of how proteostasis is maintained in eukaryotes and identifying novel treatment approaches for a wide range of human diseases that arise due to loss of proteostasis.