Mechanism and Control of Brain Microtubule Dynamics

描述（由申请人提供）：微管是动态聚合物，对细胞形状、极性和许多类型的细胞运动的确定和维持至关重要。它们表现出两种独特的动态行为，即动态不稳定和跑步，这是它们在细胞中功能的重要决定因素。这两种动态行为都是微管蛋白骨架的固有特性，而作用于微管表面或末端的微管相关蛋白控制着动力学。调节微管行为的微管相关蛋白的表达在神经元发育过程中显著改变，其失调导致包括癌症和神经变性在内的人类疾病。这一建议是基于相当多的知识体系，表明1)微管在其表面和末端具有大量的结合位点，作为细胞调节分子的靶标；2)少量此类调节分子与其特定位点的结合对微管的动态行为产生强大影响，从而影响微管的功能。通过结合体外机制方法和细胞分析，重点将放在确定和控制微管动态不稳定性和跑步行为的机制上。它将涉及确定tau蛋白如何在神经退行性tau病中稳定微管并可能错误调节动力学，例如与17号染色体相关的帕金森病额颞叶痴呆（FTDP-17）和稳定蛋白/SCG10微管不稳定蛋白家族，如何机制地调节动力学。目标是：1)在体外机制/生化水平和活细胞行为上阐明tau蛋白如何调节动态不稳定性和踩踏，FTDP-17突变形式的tau蛋白如何错误调节动力学，以及微管靶向药物如何纠正这种错误调节；2)在体外机制/生化水平和活细胞行为上确定；statesmin和SCG10家族微管不稳定蛋白如何调节动态不稳定性、跑步和负端动力学；3)确定微管末端稳定帽的大小和化学性质，并使用调节动力学的微管相关蛋白作为确定帽机制如何调节的工具。

DESCRIPTION (provided by applicant): Microtubules are dynamic polymers that are critical in the determination and maintenance of cell shape, polarity, and in many types of cellular movement. They exhibit two unique dynamic behaviors, dynamic instability and treadmilling, which are important determinants of their functions in cells. Both dynamic behaviors are intrinsic properties of the tubulin backbone, while microtubule-associated proteins acting at the surface or ends of microtubules control the dynamics. The expression of microtubule- associated proteins that regulate microtubule behavior is significantly altered during neuronal development, and their mis-regulation contributes to human diseases including cancer and neurodegeneration. This proposal is based upon a considerable body of knowledge indicating that 1) microtubules have a large number of binding sites along their surfaces and at their ends that serve as the targets for cellular regulatory molecules and 2) that the binding of small numbers of such regulatory molecules to their specific sites exerts powerful effects on the dynamic behaviors and, thus, the functions of the microtubules. By using a combination of in vitro mechanistic approaches together with analysis in cells, the focus will be on the mechanisms that determine and control the dynamic instability and treadmilling behaviors of microtubules. It will involve determination how the tau proteins, which stabilize microtubules and may mis-regulate dynamics in neurodegenerative tauopathies such as Frontotemporal Dementia with Parkinsonism linked to chromosome 17 (FTDP-17) and the stathmin/SCG10 family of microtubule destabilizing proteins, act mechanistically to modulate dynamics. The goals are 1) to elucidate at a mechanistic/biochemical level in vitro, and behaviorally in living cells, how the tau proteins regulate dynamic instability and treadmilling, how FTDP-17 mutated forms of tau mis-regulate the dynamics, and how microtubule-targeted drugs can correct the mis-regulation, 2) to determine at a mechanistic/biochemical level in vitro, and behaviorally in living cells, how the stathmin and SCG10 family of microtubule destabilizing proteins regulates dynamic instability, treadmilling, and minus end dynamics, and 3) to determine the size and chemical nature of the stabilizing cap at microtubule ends, and to use microtubule-associated proteins that modulate dynamics as tools to determine how the cap mechanism is regulated.