Mechanistic analysis of microtubule catastrophe

该项目旨在发现，在一个模型系统中，活细胞部分的集体动态行为是如何由单个组成部分的结构和生化特性决定的。微管将被用作本研究的模型系统。微管是由一种叫做“微管”的蛋白质制成的聚合物。-微管蛋白，它们在细胞分裂过程中对细胞内部的组织和遗传物质的分配起着至关重要的作用。通过整合多种方法，本研究将破译和量化个体潜在结构和生化特性之间的联系。微管蛋白和复杂的聚合动力学从它们的集体相互作用中出现。除了促进对细胞生物学基本重要性过程的理解外，该项目还强调教育影响。参与该项目的研究生将接受跨学科培训。与当地一所小学的外展伙伴关系将使代表性不足和经济条件不利的学生接触到科学研究的乐趣，同时为他们和他们的老师提供高科技但相对便宜的数字显微镜，以促进基于探究的学习和发现。这些外展活动也将为研究生、博士后和UT西南社区的其他成员提供参与科学教育的新机会。要研究的具体问题是微管突变，即微管生长到微管收缩的偶发切换。目标是为灾难的实验测量提供一个令人信服和可测试的分子解释，特别是灾难发生的频率作为聚合物浓度的函数。微管蛋白亚基。该研究将结合多种方法，包括预测计算模拟，使用机制特定的位点导向突变体&amp；#945;&#946；-微管蛋白，以及体外生化和重建。使用这套工具，我们将(i)将三种不同的生化机制纳入微管动力学的计算模型，并确定每种机制如何影响灾难预测；（ii）对微管晶格中的相邻耦合进行实验测试，这种耦合是假设会发生的，但以前无法测试；（iii）测量突变是如何改变在&amp；#945；- and &#946；-微管蛋白影响微管聚合动力学和微管的构象。微管内外的微管蛋白。总之，这些方法将解决有关微管动力学基本机制的突出问题。该项目由分子和细胞生物科学部的分子生物物理学和细胞动力学以及功能集群共同资助。

This project seeks to discover, in one model system, how collective dynamic behaviors of parts of living cells are determined by the structural and biochemical properties of the individual components. Microtubules will be used as the model system for this research. Microtubules are polymers made from a protein called αβ-tubulin, and they play essential roles in organizing the inside of the cell and in partitioning the genetic material during cell division. By integrating diverse approaches this research will decipher and quantify the connections between the underlying structural and biochemical properties of individual αβ-tubulin proteins and the complex polymerization dynamics that emerges from their collective interactions. In addition to advancing the understanding of a process of fundamental importance to cell biology, the project emphasizes educational impact. Graduate students working on the project will receive interdisciplinary training. An outreach partnership with a local elementary school will expose underrepresented and economically disadvantaged students to the fun of doing science while providing them and their teachers with access to high-tech but relatively inexpensive digital microscopes to facilitate inquiry-based learning and discovery. These outreach activities will also provide new opportunities for graduate students, postdoctoral fellows, and other members of the UT Southwestern community to become involved in science education.The specific problem to be studied is microtubule catastrophe, the sporadic switch from microtubule growing to microtubule shrinking. The goal is to provide a convincing and testable molecular explanation for experimental measurements of catastrophe, specifically how frequently catastrophe occurs as a function of the concentration of the polymerizing αβ-tubulin subunits. The research will combine a variety of approaches including predictive computational simulations, use of mechanism-specific site-directed mutants of αβ-tubulin, and in vitro biochemistry and reconstitution. Using this set of tools, we will (i) incorporate three different biochemical mechanisms into a computational model for microtubule dynamics and determine how each mechanism affects prediction of catastrophe; (ii) perform experimental tests for neighbor coupling in the microtubule lattice, something that has been hypothesized to occur but that has not been previously testable; and (iii) measure how mutations to an interacting triad of residues that is conserved in α- and β-tubulin affect microtubule polymerization dynamics and the conformation(s) of αβ-tubulin inside and outside the microtubule. Together, these approaches will address outstanding questions about the fundamental mechanisms of microtubule dynamics.This project is jointly funded by the Molecular Biophysics and Cellular Dynamics and Function clusters in the Division of Molecular and Cellular Biosciences.