Role of msps and tacc during axon guidance

描述（由申请人提供）：准确的轴突寻路是神经系统发育过程中必不可少但高度复杂的过程。轴突形成复杂功能神经元网络的机制仍然是一个主要的难题，并且与理解神经元发育异常如何出现以及神经再生治疗有关。我的长期目标是定义的逻辑，指导信息是在轴突寻路过程中的细胞骨架动力学控制的水平集成。作为一个起点，以解决这个问题，我将研究的作用MSPs和TACC，两个微管相关蛋白，最近已被确定为抑制剂的Abl酪氨酸激酶效应蛋白轨道，调节微管动力学的生长锥和介导中线轴突排斥在果蝇神经系统。我将使用遗传学，生物化学，蛋白质组学和细胞生物学检测来研究Msps，TACC和轨道功能在生长锥定义网络的相互作用，协调积极和消极的微管动力学在轴突的指导。具体而言，我将：1）确定Msps、TACC和Abl激酶途径之间相互作用的潜在遗传途径（例如Slit、Robo、Orbit），使用果蝇胚胎神经系统中的轴突寻路表型作为测定，测试Msps和TACC与Orbit相反的功能的假设，并区分可能的遗传模型; 2）使用生物化学和蛋白质组学分析来确定Msps/TACC、Orbit和Abl之间是否存在直接的物理相互作用，以及扩展和定义涉及调节果蝇细胞培养系和神经元中微管动力学的Msps和TACC相互作用网络;和3）确定Msps和TACC的细胞作用机制，使用高分辨率实时成像在非洲爪蟾生长锥。特别是，我将确定是否MSPs和TACC发挥功能拮抗作用的轨道，促进MT延伸向生长锥的前沿，或者他们是否有不同的影响MT动态爪蟾生长锥。轴突引导异常与多种遗传性神经系统疾病有关，因此这项工作可能会揭示这些缺陷是如何产生的以及可能如何预防它们。此外，参与轴突引导的机制被认为会影响轴突在神经损伤后再生的能力，因此我们可能能够利用这些信息来设计治疗方法，以允许将来再生。最后，本文研究的蛋白质在某些癌症中也存在失调。因此，本文提出的研究具有广泛的生物医学意义。

DESCRIPTION (provided by applicant): Accurate axon pathfinding is an essential yet highly complicated process during nervous system development. The mechanisms by which axons form complex functional neuronal networks are still a major puzzle and are relevant to understanding how abnormalities in neuronal development arise and also to nerve regeneration therapeutics. My long-term goal is to define the logic by which guidance information is integrated at the level of cytoskeletal dynamics control during axon pathfinding. As a starting point to address this issue, I will study the role of Msps and TACC, two microtubule-associated proteins which have been recently identified as suppressors of the Abl tyrosine kinase effector protein Orbit which regulates microtubule dynamics in the growth cone and mediates midline axon repulsion in the Drosophila nervous system. I will use genetic, biochemical, proteomic, and cell biological assays to investigate Msps, TACC and Orbit function in the growth cone to define the network of interactions which coordinate positive and negative microtubule dynamics during axon guidance. Specifically, I will: 1) define potential genetic pathways of interaction between Msps, TACC, and the Abl Kinase pathway (e.g. Slit, Robo, Orbit), using axonal pathfinding phenotypes in the Drosophila embryonic nervous system as an assay, testing the hypothesis that Msps and TACC function opposite of Orbit and distinguishing between possible genetic models; 2) use biochemical and proteomic analysis to determine if there are direct physical interactions between Msps/TACC, Orbit, and Abl, as well as to expand and define the Msps and TACC interaction networks involved in regulating microtubule dynamics in a Drosophila cell culture line and in neurons; and 3) define the cellular mechanisms of action of Msps and TACC, using highresolution live imaging in Xenopus growth cones. In particular, I will determine if Msps and TACC play a functionally antagonistic role to Orbit, by promoting MT extension towards the growth cone leading edge, or whether they have a different effect on MT dynamics in Xenopus growth cones. Abnormalities in axon guidance have been associated with multiple hereditary neurological disorders and thus this work may shed light on how these defects arise and possibly how to prevent them. Furthermore, mechanisms involved in axon guidance are thought to influence the ability of axons to regenerate after neural injury and so we may be able to use this information to design treatments to allow regeneration in the future. Finally, the proteins studied here are also misregulated in certain cancers. Thus, the research proposed here is of broad biomedical significance.