权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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区室，它们执行生存所必需的一系列功能。其中一些区室，如细胞核和线粒体，被细胞膜与细胞的其余部分隔开。其他的被称为无膜细胞器，与细胞的其余部分没有明显的物理边界。近年来人们发现，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影响，以及细胞如何利用液滴形成的相变来调节生化途径。这些发现将揭示细胞内组织的新范式，并使新型的人工微尺度生物反应器纳入这种组织。该项目将直接影响研究生和本科生，他们将在化学、生物学、物理学和材料科学的交叉领域进行这项研究。通过让K-12教师参与进来，它也将惠及高中生和中学生。每年夏天，教师小组将在首席研究员的实验室工作，开发适合年级水平的乳液科学实践内容。回到教室，这些新内容的实施将使初高中学生了解当前的科学进展及其与日常生活的联系。一种相的液滴悬浮在另一种液相中的乳液在沙拉酱或防晒霜等消费品中很常见，可以用来说明包括化学、数学、物理、生物和食品科学在内的多个学科的基本原理。首席研究员和研究生也将协助开发由教育部同事开发的K-12教育方法的化学内容，以促进高水平的科学理解。液-液共存导致真核细胞的细胞质或核质中形成被称为凝聚体的富含生物分子的水滴，直到最近才被认识到是无膜细胞器普遍存在的组织基序，但尚未得到很好的理解。该项目将为细胞内组织的液-液共存的物理化学驱动力提供新的见解，以及共存的多肽相对生化反应的潜在影响。共存相室（凝聚液滴）间溶质分布不均匀将影响生化反应速率，为通过液滴形成和溶解控制反应速率提供了一种机制。翻译后修饰，特别是关键蛋白内在无序区域的磷酸化和甲基化事件，被认为是调节无膜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肽模型系统中的相分离，作为调节酶促反应速率的一种手段。本项目主要有三个研究目标：(1)评价液滴形成/溶解控制反应的机理。(2)建立响应精氨酸甲基化的仿生肽凝聚体系统。(3)评价了不同的翻译后修饰可以控制不同液滴相的时空发生的假设，并为选择性调节酶促反应提供了一种手段。