Mechanism and Control of Brain Microtubule Dynamics

描述（由申请人提供）：微管是动态聚合物，在确定和维持细胞形状、极性和许多类型的细胞运动中至关重要。它们表现出两种独特的动力学行为，动力学不稳定性和铣削，这是它们在细胞中功能的重要决定因素。这两种动力学行为都是微管蛋白骨架的内在特性，而微管相关蛋白在微管表面或末端起作用，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期间显著改变，并且它们的错误调节导致人类疾病，包括癌症和神经变性。该建议基于大量的知识，表明1）微管沿其表面沿着和在其末端具有大量的结合位点，其用作细胞调节分子的靶，和2）少量的这种调节分子与其特定位点的结合对微管的动态行为和功能产生强大的影响。通过使用体外机制方法与细胞分析相结合，重点将放在确定和控制微管的动态不稳定性和微铣削行为的机制上。它将涉及确定tau蛋白如何稳定微管，并可能在神经退行性tau蛋白病中错误调节动力学，如与染色体17（FTDP-17）相关的额颞叶痴呆伴帕金森病和微管不稳定蛋白的stathmin/SCG 10家族，机械地调节动力学。目标是1）在体外和活细胞中的行为学上在机制/生物化学水平上阐明tau蛋白如何调节动态不稳定性和微铣削，FTDP-17突变形式的tau如何错误调节动态，以及微管靶向药物如何纠正错误调节，2）在体外和活细胞中的行为学上在机制/生物化学水平上确定，微管去稳定蛋白的stathmin和SCG 10家族如何调节动态不稳定性、微铣削和负末端动力学，以及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工具来确定帽机制如何被调节。

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.