The Mechanics of Actin-mediated Cell Protrusion

肌动蛋白介导的细胞突出的机制

• 批准号: 7797391
• 负责人: Gaudenz Danuser
• 金额: $ 29.37万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-15 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7797391
• 关键词: Abbreviations; Actins; Actomyosin; Adhesions; Binding; Biological; Cell membrane; Cells; Chemicals; Color; Coupled; Data; Development; Dissociation; Epithelial Cells; Equilibrium; F-Actin; Family member; Feedback; Figs - dietary; Filament; G Actin; Generations; Goals; Growth; Growth Factor; Image; In Situ; Joints; Kinetics; Life; Link; Measurement; Measures; Mechanics; Mediating; Methodology; Methods; Microfilaments; Microscopy; Minor; Modeling; Names; Neoplasm Metastasis; Nonlinear Dynamics; Organelles; Pathway interactions; Principal Investigator; Process; Proteins; Quantitative Microscopy; Relative (related person); Research; Resolution; Science; Side; Signal Transduction; System; Testing; Time; Tropomyosin; Work; acronyms; base; cell motility; cofilin; cofilin 2; depolymerization; network models; neuronal cell body; novel; p21 activated kinase; polymerization; programs; protein complex; research study; response; rho GTP-Binding Proteins

DESCRIPTION (provided by applicant): Protrusion of the leading edge is the first step in directed cell migration, a critical process in both cancer metastasis and normal development. It requires polymerization of actin filaments (F-actin) at the leading edge plasma membrane in exquisite balance with both network adhesion and contraction, all under the control of regulatory signals. The long term goal of my research program is to create systems-level models of the integration of these mechanical and chemical pathways as a non-steady state and spatially distributed process. The project proposed here is based on our discovery of two dynamically, molecularly, and functionally distinct but spatially overlapping F-actin networks, named lamella (La) and lamellipodium (Lp) (Ponti et al, Science 2004). The central hypothesis of this proposal suggests that cell protrusion is driven by elongation of actin filaments in the contractile La network which engages with adhesions and spans the region between the cell body and the leading edge. The Lp is a narrow, fast treadmilling F-actin network that assembles off of La-filaments via Arp2/3 and cofilin activity. However, according to our hypothesis the Lp only makes minor contributions to the generation of propulsive forces itself, but rather modulates the dynamics of La filament assembly. Thus, our model defines the Lp as a regulatory organelle of cell protrusion. To test this prediction we will integrate quantitative high-resolution live cell microcopy and image data driven modeling approaches to achieve three Specific Aims: 1.) Test the hypothesis that Lp F-actin assembles off elongating La filaments and transiently dissociates under the competing activities of tropomyosin and cofilin; 2.) Test the hypothesis that La F-actin assembly is coupled to La network contraction via RhoA signals. 3.) Test the hypothesis that Lp dynamics modulate La-mediated cell protrusion in both EGF-stimulated and random cell migration. The cell biological deliverable of this project is the deconvolution of several mechanochemical pathways by systematic in situ analysis of their modes of action and timing during cell protrusion. The technological deliverables will be a unique and robust methodology to probe the dynamic interaction of two protein assemblies and their relationship to intracellular forces in live cell analyses. Second, the non-steady state measurements provided by these methods will initiate novel numerical modelling to recapitulate the non-linear dynamics of cell protrusion.

描述（申请人提供）：前沿的突出是定向细胞迁移的第一步，是癌症转移和正常发育的关键过程。它需要肌动蛋白丝（F-actin）在质膜前缘聚合，在网络粘附和收缩的精细平衡下，所有这些都在调节信号的控制下。我的研究计划的长期目标是创建这些机械和化学途径作为一个非稳态和空间分布过程的集成的系统级模型。这里提出的项目是基于我们发现的两个动态、分子和功能不同但空间重叠的f -肌动蛋白网络，称为片层（La）和片层基（Lp） （Ponti et al, Science 2004）。该提案的中心假设表明，细胞突起是由La网络中肌动蛋白丝的伸长所驱动的，该网络与粘连作用并跨越细胞体和前缘之间的区域。Lp是一种狭窄、快速的f -肌动蛋白网络，通过Arp2/3和cofilin活性从la丝上组装而成。然而，根据我们的假设，Lp对推进力本身的产生贡献很小，而是调节了La灯丝组装的动力学。因此，我们的模型将Lp定义为细胞突出的调节细胞器。为了验证这一预测，我们将整合定量高分辨率活细胞显微复制和图像数据驱动的建模方法，以实现三个具体目标：验证Lp f -肌动蛋白在原肌凝蛋白和辅蛋白的竞争作用下聚集在拉长的La丝上并短暂分离的假设；2.） 验证La F-actin组装通过RhoA信号与La网络收缩耦合的假设。3.） 验证Lp动态调节egf刺激和随机细胞迁移中la介导的细胞突出的假设。该项目的细胞生物学成果是通过对细胞突出过程中其作用模式和时间的系统原位分析，对几种机械化学途径进行反卷积。技术成果将是一种独特而强大的方法，用于探索两种蛋白质组合的动态相互作用及其与活细胞分析中细胞内力的关系。其次，这些方法提供的非稳态测量将启动新的数值模拟，以概括细胞突出的非线性动力学。