Spatial control of actin assembly by phosphoinositides

磷酸肌醇对肌动蛋白组装的空间控制

• 批准号: 9331719
• 负责人: Paul A Janmey
• 金额: $ 44.35万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9331719
• 关键词: Actin-Binding Protein; Actins; Affect; Alpha Cell; Atomic Force Microscopy; Binding; Binding Proteins; Binding Sites; Biochemical; Biochemistry; Biological; Biophysics; Brain; Cell membrane; Cell physiology; Cells; Cellular biology; Cereals; Cholesterol; Collaborations; Computer Analysis; Cytoskeleton; Data; Defect; Disease; Electron Microscopy; Electrostatics; Elements; Employee Strikes; Enzymes; Event; Fluorescence Microscopy; Gelsolin; Goals; In Vitro; Isomerism; Lateral; Lead; Ligands; Link; Lipids; Liquid substance; Malignant Neoplasms; Mechanics; Mediating; Membrane; Membrane Lipids; Metabolism; Methods; Microfilaments; Modeling; Mole the mammal; Molecular Conformation; Mutation; Nerve Degeneration; Neurons; Neuropathy; PI3 gene; Phase; Phase Transition; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipids; Physiological; Production; Property; Proteins; Regulation; Resolution; SERPINA4 gene; Signal Transduction; Specificity; Structure; Surface; System; Temperature; Testing; Vesicle; Work; aqueous; base; biophysical analysis; cell motility; cell type; computer studies; design; experience; high resolution imaging; human disease; in vivo; membrane model; molecular dynamics; monolayer; multidisciplinary; nanoscale; novel strategies; polymerization; pressure; protein activation; public health relevance; quantum; spectroscopic imaging; spectroscopic survey

 DESCRIPTION (provided by applicant): Phosphoinositides are membrane phospholipids that control many cellular events and bind with variable levels of specificity to dozens of intracellula proteins. Defects in production or metabolism of these anionic phospholipids are associated with cancer, neuronal defects, and other diseases. The most abundant phosphoinositide in most cells types, PI4,5P2, is particularly important for regulation of cytoskeletal assembly during cell motility, differentiation and proliferation largely through its effects on numerous actin binding proteins including gelsolin, N-WASP, and formins, which are the focus of this project. Other isomers of PI4,5P2, such as PI3,5P2, are associated with neurodegeneration in several genetically distinct diseases. How specific phosphoinositides affect their ligands is much less understood than are the mutations that produce abnormal phosphoinositide production. Defining how these lipids exert their biological control at the membrane-cytoskeletal interface could lead to new approaches to limiting or reversing the abnormal function of these lipids in disease. Previous work and preliminary data show that PI4,5P2 at low mole fraction in membranes forms nanoscale clusters in the presence of physiologically relevant levels of Ca2+ and partitions into the liquid disordered phase when membranes undergo fluid phase transitions due to changes in cholesterol content or temperature. Redistribution of PI4,5P2 into these nanodomains alters its ability to nucleate actin assembly from brain extracts and to inhibit gelsolin, the actin filament severing protein. The goal of this project is to quantitatively define the conditions under which PI4,5P2 reorganizes into nanoscale membrane domains using a combination of high resolution imaging, spectroscopy, and molecular dynamics computations and to relate changes in PI4,5P2 membrane distribution to its ability to inhibit actin assembly. Biochemical analyses will test which elements of the actin regulatory system are affected when PI4,5P2 redistributes in membranes. This project involves collaboration among three groups with complementary experience in membrane biophysics, gelsolin biochemistry and the mechanics of actin polymerization; computational studies of membrane structure and mechanics; and electron microscopy with emphasis on high resolution studies of actin assembly at membranes. The multi-disciplinary study will lead to an atomic level understanding of phosphoinositide-protein interactions that will help direct strategies designed to alter phosphoinositide production, distribution, and signaling in the numerous contexts where their altered expression or distribution is linked to disease.

 描述（由适用提供）：磷酸肌醇是控制许多细胞事件并与数十个细胞内蛋白的特异性水平变化的膜磷脂。这些阴离子磷脂的生产或代谢缺陷与癌症，神经元缺陷和其他疾病有关。大多数细胞类型中最丰富的磷酸肌醇PI4,5P2对于调节细胞期间细胞骨架组件尤为重要 运动，分化和增殖在很大程度上是通过对包括凝胶蛋白，N-WASP和formins在内的众多肌动蛋白结合蛋白的影响，这是该项目的重点。 PI4,5P2的其他异构体，例如PI3,5P2，与几种遗传疾病的神经变性有关。比产生异常的磷酸肌醇产生的突变，特定的磷酸肌醇如何影响其配体的理解要少得多。定义这些脂质如何在膜 - 骨骼骨骼界面上施加其生物学控制可能会导致限制或逆转这些脂质在疾病中的异常功能的新方法。先前的工作和初步数据表明，在存在物理相关水平的Ca2+水平和分区中，膜中低分子级分的PI4,5P2在膜含量或温度变化导致的液体相变到液体失调相中。将PI4,5P2重新分布到这些纳米域中，改变了其从脑提取物中核肌动蛋白组装的能力，并抑制凝胶蛋白，肌动蛋白（肌动蛋白）几种蛋白质。该项目的目的是定量定义PI4,5P2使用高分辨率成像，光谱和分子动力学计算的组合，将PI4,5P2重组为纳米级膜结构域，并将PI4,5P2膜分布的变化与抑制ATCIN组件的能力相关联。生化分析将测试当PI4,5P2重新分布在膜中时，肌动蛋白调节系统的哪些要素会受到影响。该项目涉及在膜生物物理学，凝胶素生物化学和肌动蛋白聚合的机制方面具有完整经验的三个小组之间的合作。膜结构和力学的计算研究；和电子显微镜，重点是膜组件在膜上的高分辨率研究。多学科研究将导致对磷酸肌醇 - 蛋白质相互作用的原子水平的理解，这些相互作用将有助于指导旨在改变其表达或分布与疾病有关的众多情况下，旨在改变磷酸肌醇的产生，分布和信号传导。