Control of cargo distributions by microtubule motor physical interactions with cargo, cytoplasm and MAPs

通过微管运动与货物、细胞质和 MAP 的物理相互作用控制货物分布

• 批准号: 9289581
• 负责人: Jun Allard
• 金额: $ 34.76万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9289581
• 关键词: Address; Affinity; Alpha Cell; Alzheimer' s Disease; Axon; Behavior; Biological Assay; Cells; Cereals; Charge; Code; Computer Simulation; Cytoplasm; Data; Dimensions; Disease; Dynein ATPase; Environment; Exhibits; Family; Goals; Heterogeneity; Impairment; Intracellular Transport; Kinesin; Kinetics; Lead; Length; Lipids; MAPT gene; Maps; Measures; Mechanics; Methods; Microtubule-Associated Proteins; Microtubules; Modeling; Molecular; Motor; Motor Pathways; Mutation; Nature; Neurons; Pathologic; Phosphorylation; Property; RNA; RNA Splicing; Regulation; Regulatory Pathway; Research; Rheology; Site; Sorting - Cell Movement; Specificity; Structure; Surface; System; Tauopathies; Testing; Therapeutic; Variant; Viscosity; Work; base; combat; combinatorial; density; dynactin; in vivo; laser tweezer; mechanical properties; molecular scale; mutant; novel; novel strategies; physical property; public health relevance; response; simulation; tau Proteins; tau dysfunction; viscoelasticity

PROJECT SUMMARY The major open question in microtubule motor research is to determine how cargo-scale motor behavior is regulated (at the molecular scale) to orchestrate control of a cell's spatial organization (on the scale of 10-100 microns), simultaneously for all of motor- driven intracellular traffic. This involves the microtubule associated protein Tau, the hallmark of Tauopathy diseases. Challenges arise because of the combinatorial complexity of Tau variants and the multi-scale nature of the question – two challenges for which computational modeling is particularly well suited to confront. In Aim 1, we will develop a model to simulate motor-MAP kinetics and how these lead to cargo transport. We hypothesize that a microtubule adorned with MAPs and other molecules can selectively influence cargo localization depending on the cargo's size and mechanical deformability. This selectivity can be understood in terms of the MAP's size, mechanical properties and abundance, which together provide a traffic coding system that is mis- regulated in disease. We will develop a computational model and simulate motor transport at the cargo-scale to explore specificity and multiplexing by MT-cargo spacing control. A key missing parameter is the motor's attachment rates, which have been so far too technically challenging to measure directly and will therefore require a novel experimental-theoretical assay. We will then simulate motor transport in a 1-dimensional array of microtubules to identify cargo-scale parameters that sensitively lead to cell-scale localization, using known spatial heterogeneity of, e.g., Tau across axons. In Aim 2, we will explore the spacing-based aspect of motor modulators. We hypothesize that many transport-regulating molecules operate in part by tuning the spacing (mean and variance of distance) between the microtubule and cargo. Spacing-based regulation endows the system with control properties not present in other modes of regulation. We will develop an optical tweezer-based assay to quantify the modulation of transport parameters by tuning MT-cargo spacing, and a simulation-based inference method to measure spacing for arbitrary MAPs. We will specifically work to understand the regulatory mechanism of highly-structured molecules such as Dynactin and Rabs, and highly-disordered molecules such as Tau and MAP2. In Aim 3, we will explore the effects of the cargo's and cell's local rheology. We hypothesize that both the internal dynamics of surface- bound molecules on the cargo, and the cell's local rheology influence transport properties. This provides the system with a natural cargo sorting mechanism. Using our simulation, we will quantify the influence of the cargo's internal viscosity (low for vesicular cargo, intermediate for lipid droplets, and high for rigid cargo like RNA) and how this interacts with the viscoelasticity of the cytoplasm.

项目摘要 微管运动研究中的主要问题是确定货物规模如何 运动行为受到调节（在分子尺度上），以协调控制细胞的运动， 空间组织（在10-100微米的尺度上），同时用于所有的运动- 驱动的细胞内交通。这涉及微管相关蛋白Tau， Tauopathy疾病的标志。挑战的出现是因为 Tau变体的复杂性和问题的多尺度性质-两个挑战 计算建模特别适合于面对这些问题。在目标1中，我们 开发一个模型来模拟电机MAP动力学以及这些如何导致货物运输。 我们假设，微管与地图和其他分子装饰， 根据货物的尺寸和机械性能选择性地影响货物定位 变形性这种选择性可以根据MAP的尺寸、机械性能和机械性能来理解。 属性和丰度，它们一起提供了一个交通编码系统，这是错误的， 在疾病中调节。我们将开发一个计算模型并模拟电机 货物规模的运输，以探索MT货物间距的特异性和多路复用 控制一个关键的缺失参数是电机的附着率，这一直是如此 技术上太具有挑战性，无法直接测量，因此需要一种新的 实验-理论分析然后，我们将在一维模型中模拟运动运输。 微管阵列用于识别敏感地导致细胞规模的货物规模参数 定位，使用已知的空间异质性，例如，Tau穿过轴突。在目标2中， 将探索基于空间的运动调节器。我们假设， 转运调节分子部分地通过调节间隔（平均值和方差）来运作 （1）微管与货物之间的距离。基于空间的监管赋予了 具有其他调节模式中不存在的控制特性的系统。我们将开发 一种基于光镊的测定，通过以下方式量化传输参数的调制： 调整MT货物间距，以及基于模拟的推理方法来测量间距 对于任意映射。我们将具体工作，以了解监管机制， 高度结构化的分子，如Dynactin和Rabs，以及高度无序的 Tau和MAP 2等分子。在目标3中，我们将探讨货物的影响， 和细胞局部流变学。我们假设表面的内部动力学- 货物上的结合分子，以及细胞的局部流变学影响运输 特性.这为系统提供了自然的货物分类机制。使用我们 模拟，我们将量化货物的内部粘度的影响（低， 囊泡货物，脂质液滴的中间，和刚性货物如RNA的高）， 这是如何与细胞质的粘弹性相互作用的。