Role of sumoylation during stress signaling responses

项目摘要 这个MIRA提案的总体目标是了解真核生物应激的机制， 反应途径是由蛋白质的翻译后修饰调节的， 修饰符SUMO。细胞必须响应和适应物理和/或化学应激，这些应激可以不可逆地 致命地破坏重要的大分子。应激反应途径通常调节转录， 翻译、蛋白质活性或相互作用以及根据特定应激及其严重性的代谢。在 在真核细胞中，应激暴露导致特定蛋白质的类小泛素化;然而，类小泛素化的作用 在大多数压力反应仍然是不确定的。我们知识上的这一差距是我们实现这一目标的关键障碍。 了解动态细胞应激调节和适应，及其在人类中的功能重要性 健康，其中压力信号在各种疾病（例如心脏病，癌症， 神经变性、II型糖尿病）。研究蛋白质类小泛素化减轻 压力相关的细胞损伤，我们的研究小组一直使用芽殖酵母作为模式生物， 确定sumoylation在不同的压力下的具体作用。最初，我们专注于高渗应激， 发现酵母朊病毒蛋白Cyc 8和它的结合伴侣Tup 1是快速和短暂的 sumoylated在高渗胁迫。此外，我们发现Cyc 8-Tup 1复合物形成相- 在高渗胁迫的初始阶段，Cyc 8类小泛素化对于细胞核的分离很重要。 在细胞适应压力的过程中及时解决这些病灶。我们假设Cyc 8-Tup 1 在高渗胁迫期间，复合物的瞬时聚结进入液-液相分离（LLPS）改变了 复合物与染色质的相互作用，允许高渗应激反应的最佳表达 基因.在高渗应激研究的同时，我们继续探索类小泛素化在高渗应激中的作用。 其他压力。因此，MIRA机制是我们继续研究的理想选择，因为它具有灵活性 在两个快速发展的领域的关键交叉点及时和突出的调查途径：压力依赖 SUMO化和LLPS形成的动力学。在这里，我们建议使用遗传学，细胞 生物学和体外生物化学，以揭示sumoylation的功能的总体原则， 在不同的压力和特定的作用sumoylation。我们未来五年的目标 本研究旨在探讨以下问题：1）多价类小泛素化在细胞内的功能目的是什么？ 在特定的应激反应中复杂吗？2)类小泛素化的功能有没有一般的原则 跨越不同的压力3)类小泛素化通过什么机制调节胁迫诱导的LLPS 动力学？

PROJECT SUMMARY The overall objective of this MIRA proposal is to understand the mechanisms through which eukaryotic stress response pathways are regulated by post-translational modification of proteins with the small ubiquitin-like modifier SUMO. Cells must respond and adapt to physical and/or chemical stresses that can irreversibly and lethally damage essential macromolecules. Stress-response pathways generally adjust transcription, translation, protein activity or interactions, and metabolism according to the particular stress and its severity. In eukaryotic cells, stress exposure leads to sumoylation of specific proteins; however, the role(s) of sumoylation during most stress responses still remain uncertain. This gap in our knowledge presents a key barrier to our understanding of dynamic cellular stress regulation and adaptation, and its functional importance in human health where stress signaling becomes strained or co-opted in various diseases (e.g. heart disease, cancer, neurodegeneration, type II diabetes). To investigate mechanisms by which protein sumoylation mitigates stress-related cellular damage, our research group has been using budding yeast as a model organism to identify specific roles for sumoylation during distinct stresses. Initially, we focused on hyperosmotic stress and discovered that the yeast prion protein Cyc8 and its binding partner Tup1 are rapidly and transiently sumoylated during hyperosmotic stress. In addition, we found that the Cyc8-Tup1 complex forms phase- separated nuclear foci during the initial stages of hyperosmotic stress, and Cyc8 sumoylation is important for the timely resolution of these foci during cellular adaptation to the stress. We hypothesize that the Cyc8-Tup1 complex's transient coalescence into liquid-liquid phase separations (LLPS) during hyperosmotic stress alters the complex's interactions with chromatin, allowing for the optimal expression of hyperosmotic stress-response genes. In parallel to the studies on hyperosmotic stress, we have continued exploring the role of sumoylation in other stresses. Thus, the MIRA mechanism is ideal for our continuing studies due to its flexibility to pursue timely and salient avenues of inquiry at the key intersection of two rapidly-evolving fields: stress-dependent sumoylation and the kinetics of LLPS formation. Here, we propose to use a combination of genetics, cell biology, and in vitro biochemistry to uncover both overarching principles for the functions of sumoylation across multiple stresses and specific roles for sumoylation during distinct stresses. Our goals over the next five years are to explore the following questions: 1) What are the functional purposes for multivalent sumoylation within a complex during specific stress responses? 2) Are there general principles for the function(s) of sumoylation across divergent stresses? 3) Through what mechanism(s) does sumoylation modulate stress-induced LLPS dynamics?