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Microfilament Function in Cell Polarity

微丝在细胞极性中的功能

基本信息

批准号：
10399460
负责人：
Anthony P. Bretscher
金额：
$ 82.85万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-05-14 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10399460
关键词：
Address Apical Area Biochemical Biogenesis Cell Adhesion Molecules Cell Polarity Cell division Cell membrane Cell physiology Cells Cellular Morphology Cystic Fibrosis Transmembrane Conductance Regulator Cytoskeleton Daughter Defect Dependence Disease Elements Endocytosis Epithelial Epithelial Cells Exocytosis Functional disorder Growth Growth Factor Receptors Image Individual Knowledge Lipids Malignant Neoplasms Medical Membrane Membrane Protein Traffic Mesenchymal Microfilaments Microtubules Modeling Molecular Motors Morphology Mothers Motor Myosin ATPase Myosin Type V Neoplasm Metastasis Neuromuscular Junction Neurons Organ Organelles Pathway interactions Process Proteins Proteome Regulation Research Secretory Vesicles Signal Pathway Signal Transduction Structure Surface Synapses System Translating Vertebrates Vesicle Work Yeasts base cellular microvillus ezrin insight link protein mutant neurotransmitter release polarized cell segregation temporal measurement transmission process vesicle transport

项目摘要

Project Summary/Abstract Cells generate biochemically and morphologically distinct plasma membrane domains by polarizing their internal structure and biosynthetic pathways. Without this polarity, cells could not perform functions such as transport across epithelia and signal transmission in neurons. Further, improper regulation of cell polarity can initiate cancer metastasis, as in unregulated epithelial the mesenchymal transition (EMT). Multiple processes are interwoven for cell polarization, including assembly of a polarized cytoskeleton, synthesis of lipids and proteins with their transport to the appropriate surface, and exocytosis and endocytosis. While long-range transport often involves microtubules, local transport and morphological features of the plasma membrane generally involves an interplay between signaling pathways, microfilaments and membrane traffic. While much is known about each individual area, our two projects address the critical gap in understanding of how they are coordinated. First, we aim to understand how structural elements and signaling pathways converge to define the morphology of a specific membrane domain, using the microvilli on the apical aspect of epithelial cells as our model. We have defined the major structural components and provided insight into regulation of the critical microfilament- membrane linking protein ezrin. We will elucidate the signaling pathways that impinge on ezrin and other factors to restrict microvilli to the apical surface, to determine how microvilli impact the membrane proteome, and to identify the additional functions and regulators of ezrin. Second, we study how motor-based transport along microfilaments is coordinated with membrane traffic. We utilize yeast where microfilaments serve as tracks for the myosin-V based transport of secretory vesicles for bud growth and in organelle segregation between mother and daughter during cell division. We will define fundamental aspects of organelle transport by investigating how the myosin-V picks up secretory vesicles, transports and delivers them in coordination with vesicle biogenesis and exocytosis. We have established a system with high temporal and spatial precision for imaging the delivery cycle of a molecular motor, as well as steps in exocytosis, and shown that motor release is coordinated with, and dependent on, exocytosis. We will undertake an extensive mechanistic analysis of the timing, dependencies, and coordination of steps in exocytosis and motor release exploiting available and newly generated mutants. As the molecules involved are conserved between yeast and vertebrates, most notably identified from the extensive studies of neurotransmitter release at the synapse, the findings will be of general significance. It is important to note that exocytosis in yeast is orders of magnitude slower that at the neuromuscular junction, permitting far greater temporal resolution, and in a much more experimentally accessible system. Moreover, many diseases are associated with defects in molecular motors, including myosin-Vs, and components involved in exocytosis. The proposed research will provide fundamental and medically relevant insights into two critical aspects of cell polarity, local regulation of cell morphology and organelle delivery.

项目总结/摘要细胞产生生物化学和形态学上不同的质膜结构域通过极化其内部结构和生物合成途径。如果没有这种极性，细胞就不能执行诸如运输等功能，和神经元中的信号传递。此外，细胞极性的不当调节可引发癌症转移，如在不受调节的上皮间质转化（EMT）中。多个进程是交织的细胞极化，包括组装极化的细胞骨架，脂质和蛋白质的合成并将其转运到适当的表面，以及胞吐和胞吞作用。虽然远距离运输通常涉及微管，局部运输和质膜的形态特征通常涉及信号通路、微丝和膜运输之间的相互作用。虽然我们对每一种都有很多了解，在个别领域，我们的两个项目解决了在理解它们如何协调方面的关键差距。一是目的是了解结构元件和信号通路如何会聚，以定义一个细胞的形态。特异性膜结构域，使用上皮细胞顶端的微绒毛作为我们的模型。我们有定义了主要的结构成分，并提供了对关键微丝调节的见解- 膜连接蛋白ezrin。我们将阐明影响ezrin和其他因子的信号通路将微绒毛限制在顶端表面，确定微绒毛如何影响膜蛋白质组，确定埃兹林的其他功能和调节剂。其次，我们研究了以机动车为基础的交通沿着微丝与膜运输相协调。我们利用酵母，其中微丝作为轨道，基于肌球蛋白V的芽生长分泌囊泡的运输和母体间细胞器分离和女儿在细胞分裂过程中我们将通过研究细胞器如何运输来定义细胞器运输的基本方面肌球蛋白-V拾取分泌囊泡，并与囊泡生物合成协调运输和递送它们和胞吐作用。我们已经建立了一个系统，具有高的时间和空间精度的成像交付分子马达的循环以及胞吐的步骤，并表明马达释放与，依赖于胞吐作用。我们将进行广泛的机械分析的时间，依赖关系，以及利用可用的和新产生的突变体的胞吐和马达释放步骤的协调。作为所涉及的分子在酵母和脊椎动物之间是保守的，最值得注意的是从广泛的神经递质在突触释放的研究，该发现将具有普遍意义。重要的是要注意酵母中的胞吐作用比神经肌肉接头处慢几个数量级，更高的时间分辨率，并且在一个更实验性的系统中。此外，许多疾病与分子马达缺陷有关，包括肌球蛋白-Vs和参与胞吐作用的成分。拟议的研究将为细胞的两个关键方面提供基础性和医学相关的见解极性、细胞形态的局部调节和细胞器递送。