Understanding microtubule regulation during the making and maintenance of axons

了解轴突形成和维护过程中的微管调节

• 批准号: BB/L000717/1
• 负责人: Andreas Prokop
• 金额: $ 51.56万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FL000717%2F1
• 关键词: Understanding; microtubule; regulation; during; making

Axons are slender processes of neurons extending up to meters across the body, serving as information highways that wire the nervous system. Failure to grow axons during development is either fatal or causes developmental brain disorders. Failure to re-grow axons after injury or stroke is an essential cause for lifelong disabilities. Failure to maintain axons in the ageing brain is considered an important cause of neurodegeneration. Pharmacological studies have demonstrated that axon growth and maintenance are essentially mediated by the highly dynamic microtubule (MT) cytoskeleton. However, how MTs are genetically regulated to promote axon growth and maintenance is not understood. The overarching aim of this project is to deliver such understanding, thus bridging an important gap in our knowledge about brain development, regeneration and ageing in both health and disease. MTs are filamentous, highly dynamic tubulin polymers that form the backbone of axons. MTs provide structural support to axons as well as highways of intracellular transport from and to the cell body. The directed extension of MTs drives axon growth, whereas their destabilisation correlates with axon retraction or degeneration. MT dynamics continue throughout an axon's life (i.e. up to decades) suggesting that axonal maintenance involves steady-state turn-over of MTs. MTs extend/retract through polymerisation/depolymerisation at their plus ends, and their plus ends interact with the intracellular environment to determine the direction and extend of MT elongation. Various proteins have been reported to regulate MT plus end dynamics, and these include EBs (end binding proteins), +TIPs (proteins binding to EBs), XMAP215 (polymerising MTs), DOUBLECORTIN (stabilising MT plus ends), STATHMIN (sequestering free tubulin), and proteins of cell cortex and organelles that can interact with MT plus ends. The principal molecular functions of most of these MT plus end regulators are known in vitro, and various have been linked to brain disorders clearly illustrating their importance in the nervous system. However, functional studies of these proteins in different neuron systems have produced only mild axon phenotypes (if any), falling short of demonstrating the essential roles that MT plus end dynamics are expected to play during axon growth and maintenance. I hypothesise that the different MT plus end regulators contribute to one common MT plus end machinery and that their functions overlap within this machinery. Deciphering this machinery and identifying the key set of components that drive axon growth and maintenance is therefore an important challenge and the overarching objective of this project. This challenge requires novel approaches. We use a simple genetic model organism, the fruit fly Drosophila. Research in Drosophila is fast, cheap and capitalises on efficient genetic strategies. It has been a powerhouse for the discovery of mechanisms and concepts underpinning brain development and function, many of which are evolutionary well conserved and have laid important foundations for research in higher animals. We have 8 years of experience with work on cytoskeletal regulation during axon growth in Drosophila and have provided substantial proof of principle that novel understanding can be generated and applied to higher animals. Our pilot studies of MT plus end regulators reveal characteristic axon aberrations and allow us to formulate detailed working models. On this basis, we will study cellular mechanisms of MT plus end regulators and functional links between them. Our work will prove the importance of MT plus end machinery during axon growth and maintenance and deliver a step change in understanding of how this machinery works. This will have important implications for research on developmental brain disorders, neuroregeneration, neurodegenerative diseases and ageing.

轴突是神经元的细长过程，该神经元延伸到整个体内，充当神经系统电线的信息高速公路。发育过程中未能生长轴突是致命的，要么引起发育性脑部疾病。受伤或中风后不重新生长轴突是终身残疾的重要原因。无法在衰老大脑中维持轴突被认为是神经退行性的重要原因。药理学研究表明，轴突生长和维持基本上是由高度动态的微管（MT）细胞骨架介导的。但是，尚不清楚如何在基因调节MT遗传调节以促进轴突的生长和维持。该项目的总体目的是提供这种理解，从而弥合我们对健康和疾病中大脑发育，再生和衰老的重要差距。 MT是形成轴突骨架的丝状，高度动态的微管蛋白聚合物。 MT为轴突以及细胞内转运的高速公路提供结构支撑。 MTS的定向延伸驱动轴突的生长，而它们的不稳定与轴突回缩或变性有关。 MT动力学在整个轴突的生命（即数十年）中继续，这表明轴突维持涉及MT的稳态转换。 MT通过聚合/解聚末端扩展/缩回，其加末端与细胞内环境相互作用，以确定MT伸长的方向和延伸。 Various proteins have been reported to regulate MT plus end dynamics, and these include EBs (end binding proteins), +TIPs (proteins binding to EBs), XMAP215 (polymerising MTs), DOUBLECORTIN (stabilising MT plus ends), STATHMIN (sequestering free tubulin), and proteins of cell cortex and organelles that can interact with MT plus ends.大多数这些MT Plus最终调节剂的主要分子功能在体外都是已知的，并且各种与脑疾病有关，清楚地说明了它们在神经系统中的重要性。然而，这些蛋白质在不同神经元系统中的功能研究仅产生了轻度的轴突表型（如果有的话），没有证明MT Plus End Dynamics在轴突生长和维持过程中发挥作用的基本作用。我假设不同的MT Plus End调节器有助于一种常见的MT Plus End机械，并且它们的功能在此机械中重叠。因此，破译这种机械并确定驱动轴突增长和维护的组件集集是该项目的重要挑战和总体目标。 这个挑战需要新颖的方法。我们使用简单的遗传模型生物，即果蝇果蝇。果蝇的研究快速，便宜，并利用有效的遗传策略。它一直是发现脑发育和功能的机制和概念的强大力量，其中许多是进化良好的保守性，并为高等动物的研究奠定了重要的基础。我们在果蝇轴突生长期间在轴突生长过程中有8年的研究经验，并提供了实质性的原则证明，可以产生新的理解并应用于高等动物。我们对MT Plus最终调节器的试点研究揭示了特征性的轴突畸变，并使我们能够制定详细的工作模型。在此基础上，我们将研究MT Plus最终调节剂的细胞机制以及它们之间的功能联系。我们的工作将证明MT Plus End机械在轴突增长和维护过程中的重要性，并在理解该机械工作方式方面做出了变化。这将对有关发育性脑疾病，神经病变，神经退行性疾病和衰老的研究具有重要意义。

项目成果

Automated approaches for the qualitative and quantitative analysis of microtubule networks

微管网络定性和定量分析的自动化方法

• 发表时间: 2017
• 作者: Costa-Gomes B

Drosophila CLIP-190 and mammalian CLIP-170 display reduced microtubule plus end association in the nervous system.

• DOI: 10.1091/mbc.e14-06-1083
• 发表时间: 2015-04-15
• 期刊: Molecular biology of the cell
• 影响因子: 3.3
• 作者: Beaven R;Dzhindzhev NS;Qu Y;Hahn I;Dajas-Bailador F;Ohkura H;Prokop A
• 通讯作者: Prokop A

A novel electronic assessment strategy to support applied Drosophila genetics training in university courses.

• DOI: 10.1534/g3.115.017509
• 发表时间: 2015-02-25
• 期刊: G3 (Bethesda, Md.)
• 作者: Fostier M;Patel S;Clarke S;Prokop A
• 通讯作者: Prokop A

ALFRED: automated image analysis application to inform mathematical modelling of microtubule networks in nerve cells

ALFRED：自动图像分析应用程序，为神经细胞中微管网络的数学建模提供信息

• 发表时间: 2018
• 作者: Costa-Gomes, B.

Functional and Genetic Analysis of Spectraplakins in Drosophila.

• DOI: 10.1016/bs.mie.2015.06.022
• 发表时间: 2015-08
• 期刊: Methods in enzymology
• 作者: Ines Hahn;M. Ronshaugen;N. Sánchez-Soriano;A. Prokop