Dynamic formation/disassembly of membraneless organelle model systems by post-translational modification: Mechanisms and consequences

通过翻译后修饰动态形成/分解无膜细胞器模型系统：机制和后果

基本信息

批准号：
1715984
负责人：
Christine Keating
金额：
$ 90万
依托单位：
Pennsylvania State Univ University Park
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-15 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1715984&HistoricalAwards=false
关键词：
Dynamic formation disassembly membraneless organelle

项目摘要

Living cells contain different subcellular compartments that perform a range of functions necessary for survival. Some of these compartments, such as the nucleus and mitochondria, are separated from the rest of the cell by membranes. Others, termed membraneless organelles, lack any obvious physical boundary from the rest of the cell. It was recently discovered that many membraneless organelles are actually liquid droplets formed by intracellular phase separation. This project will investigate the consequences of droplet formation on biochemical reactions and how cells could take advantage of droplet-forming phase transitions to regulate biochemical pathways. The findings will uncover new paradigms for intracellular organization and enable new classes of artificial microscale bioreactors that incorporate such organization. The project will directly impact students at the graduate and undergraduate levels, who will perform this research at the intersection of chemistry, biology, physics and materials science. By involving K-12 teachers it will also reach high school and middle school students. Small teams of teachers will work in the Principal Investigator's laboratory each summer developing grade-level appropriate hands-on content in emulsion science. Back in their classrooms, implementation of this new content will engage middle and high school students with current scientific progress and its connection to their everyday lives. Emulsions where droplets of one phase are suspended in another liquid phase are common in consumer products such as salad dressings or sunscreens, and can be used to illustrate fundamental principles in multiple disciplines including chemistry, mathematics, physics, biology, and food science. The Principal Investigator and graduate students will also aid in development of chemistry content for a K-12 education approach being developed by colleagues in the Education department to facilitate high-level science comprehension.Liquid-liquid phase coexistence, which causes biomolecule-rich aqueous droplets termed coacervates to form in the cytoplasm or nucleoplasm of eukaryotic cells, has only recently been realized as a pervasive organizational motif for membraneless organelles, and is not yet well understood. This project will provide new insight into physicochemical driving forces underlying intracellular organization by liquid-liquid phase coexistence, as well as potential consequences of coexisting peptide-rich phases for biochemical reactions. Non-uniform solute distribution between coexisting phase compartments (coacervate droplets) will impact the rates of biochemical reactions, providing a mechanism to control reaction rates via droplet formation and dissolution. Post-translational modifications, specifically phosphorylation and methylation events in intrinsically disordered regions of key proteins, are thought to be a major mechanism for regulating the formation and dissolution of membraneless organelles. This project will use serine phosphorylation and arginine methylation to control phase separation in peptide-based model systems, as a means of regulating the rates of enzymatic reactions. This project has three research objectives: (1) Evaluate mechanisms for reaction control by droplet formation/dissolution. (2) Develop biomimetic peptide coacervate system that responds to arginine methylation. (3) Evaluate the hypothesis that spatial and temporal occurrence of distinct droplet phases can be controlled by different post-translational modifications, and provides a means of selectively modulating enzymatic reactions.

活细胞包含不同的亚细胞隔室，这些隔室执行了生存所需的一系列功能。这些区室中的一些，例如细胞核和线粒体，通过膜与细胞的其余部分分离。其他称为膜细胞器的人则缺乏细胞其余部分的任何明显的物理边界。最近发现，许多无膜细胞器实际上是由细胞内相分离形成的液滴。该项目将研究液滴形成对生化反应的后果，以及细胞如何利用液滴形成的相跃迁来调节生化途径。这些发现将揭示针对细胞内组织的新范式，并启用结合这种组织的新型人工显微镜生物反应器。该项目将直接影响研究生和本科级别的学生，他们将在化学，生物学，物理和材料科学的交集上进行这项研究。通过参与K-12老师，它也将吸引高中和中学生。小型教师团队将在每年夏天在首席研究人员的实验室工作，以开发乳液科学中适当的级别动手内容。回到他们的课堂上，实施这些新内容将使中学和高中生具有当前的科学进步及其与日常生活的联系。悬浮在另一个液相的一阶段液滴的乳液在消费产品（例如沙拉敷料或防晒霜）中很常见，可用于说明包括化学，数学，物理学，生物学和食品科学在内的多个学科中的基本原理。 The Principal Investigator and graduate students will also aid in development of chemistry content for a K-12 education approach being developed by colleagues in the Education department to facilitate high-level science comprehension.Liquid-liquid phase coexistence, which causes biomolecule-rich aqueous droplets termed coacervates to form in the cytoplasm or nucleoplasm of eukaryotic cells, has only recently been realized as a pervasive organizational无膜细胞器的主题，尚未得到充分理解。该项目将通过液 - 液相共存，为细胞内组织的物理化学驱动力提供新的见解，以及在生化反应中共存富含肽的相位的潜在后果。共存相室（凝聚液）之间的不均匀溶质分布将影响生化反应的速率，从而通过液滴形成和溶解来控制反应速率的机制。翻译后修饰，特别是关键蛋白质本质上无序区域中的磷酸化和甲基化事件，被认为是调节膜无细胞器形成和溶解的主要机制。该项目将使用丝氨酸磷酸化和精氨酸甲基化来控制基于肽的模型系统中的相位，以调节酶促反应速率。该项目具有三个研究目标：（1）评估通过液滴形成/溶解的反应控制机制。（2）发展对精氨酸甲基化反应的仿生肽凝聚系统。（3）评估以下假设：可以通过不同的翻译后修饰来控制不同的液滴相位的空间和时间出现，并提供了一种选择性调节酶促反应的方法。