Cytoplasmic organization by phase separation

项目摘要/摘要(Pi GladFelter，AS) 细胞必须在时间和空间上划分生物化学。一种新的受欢迎的组织机制 是生物分子的缩合。在许多情况下，凝析油通过弱的、多价的相互作用形成 无序的蛋白质和核酸。这些相互作用决定了凝析油的物质状态，如 如粘度、表面张力和孔隙率，进而影响浓度、反应和传输速率 关键组份的凝析油进、出、出。在理解细胞如何控制方面有很大的差距 凝析油在哪里形成，哪些分子共同组装，以及凝析油物质状态如何影响 功能。我们发现了凝结物在控制核分裂和细胞方面的生理功能。 丝状真菌Ashbya Cotsypii的极性。这些凝析油可以控制平移并形成 通过一种名为Whi3的RNA结合蛋白与对核分裂(细胞周期蛋白)和细胞重要的靶RNA结合 极性(福尔明)。这个细胞系统的强大之处在于，我们可以将物理属性和位置联系起来 浓缩为蛋白质翻译、细胞形状和核分裂的功能输出。世界银行的目标是 建议的工作是确定蛋白质、RNA和细胞膜中的结构元素如何控制 冷凝液在电解槽中的物质状态、位置和功能。我们将确定纳米尺度如何 蛋白质和RNA序列的特征促使凝析油的中尺度物理状态在空间上形成格局 蛋白质翻译。我们使用了一套先进的成像、遗传学、生物物理学和建模的跨学科套件 解决这些尚未为任何阶段分离所理解的基本开放问题的方法 系统。具体地说，我们将：目标1：确定蛋白质隐藏结构域的作用。我们 假设瞬时有序状态促进特定的蛋白质-蛋白质相互作用和凝聚 材料特性。目的2.建立基于RNA的支架的结构和功能。我们假设 该信使核糖核酸通过碱基配对形成了一个高阶网络，决定了凝析油的性质。目标3： 描述膜平台如何控制凝析油组件。我们假设子宫内膜 提供装配地点，以指定冷凝液的位置。这项拟议的工作将定义蛋白质如何 利用结构、RNA支架和细胞膜来控制属性、功能和位置 细胞中冷凝物的数量。大量的发现强调了康德斯塔的重要性，这些发现与 凝结物形成多种人类疾病，包括癌症和神经退行性疾病。 虽然凝析油无疑会影响生物化学，但我们还不了解凝析油是如何影响生物化学的。 实际上有助于正常的细胞功能，这对于理解它们的故障是如何导致人类 病理学。

Project Summary/Abstract (PI Gladfelter, AS) Cells must compartmentalize biochemistry in time and space. A newly appreciated mechanism of organization is biomolecular condensation. In many cases, condensates form via weak, multivalent interactions among disordered proteins and nucleic acids. These interactions determine the material states of condensates such as viscosity, surface tension and porosity, which in turn impact the concentrations, reaction and transport rates in, out and within condensates of key constituents. There are major gaps in understanding how cells control where condensates form, which molecules coassemble, and how condensate material state contributes to function. We discovered a physiological function for condensates in controlling nuclear division and cell polarity in the filamentous fungus, Ashbya gossypii. These condensates can control translation and are formed by an RNA-binding protein called Whi3 binding to target RNAs important for nuclear division (cyclins) and cell polarity (formins). The power of this cell system is that we can link physical properties and locations of condensates to functional outputs of protein translation, cell shape and nuclear division. The goals of the proposed work are to determine how structured elements in proteins, RNAs and cell membranes control the material state, location and function of condensates in the cell. We will determine how nanometer scale features of protein and RNA sequences promote mesoscale physical states of condensates to spatially pattern protein translation. We use an interdisciplinary suite of advanced imaging, genetic, biophysical and modeling approaches to tackle these fundamental open problems that not yet understood for any phase-separating system. Specifically, we will: Aim 1: Determine roles of hidden structured domains of proteins. We hypothesize that transiently ordered states promote specific protein-protein interactions and condensate material properties. Aim 2. Establish the architecture and function of RNA-based scaffolds. We hypothesize that mRNA forms a higher-order network using base-pairing that determines condensate properties. Aim 3: Delineate how membrane platforms control condensate assemblies. We hypothesize that endomembranes provide sites of assembly to specify the location of condensates. The proposed work will define how protein structure, RNA scaffolds and cell membranes are harnessed to control the properties, functions and locations of condensates in cells. The importance of condesates is underscored by numerous findings that link aberrant formation of condensates to multiple human diseases, including cancer and neurodegenerative diseases. While it is clear condensates undoubtably impact biochemistry, we do not yet understand how condensates actually contribute to normal cell function which is critical to understand how their malfunction leads to human pathologies.