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件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蛋白的蛋白质制成的聚合物，它们在组织细胞内部和在细胞分裂期间分配遗传物质方面发挥着重要作用。 通过整合不同的方法，这项研究将破译和量化的基础结构和生物化学特性之间的连接个别#945;#946;-微管蛋白和复杂的聚合动力学，从他们的集体相互作用。除了促进对细胞生物学具有根本重要性的过程的理解外，该项目还强调教育影响。从事该项目的研究生将接受跨学科培训。与当地一所小学的外联伙伴关系将使代表性不足和经济上处于不利地位的学生接触到做科学的乐趣，同时为他们和他们的教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，博士后研究员和UT西南社区的其他成员提供新的机会，参与科学教育。要研究的具体问题是微管灾难，从微管生长到微管收缩的零星切换。我们的目标是提供一个令人信服的和可测试的分子解释的实验测量的灾难，特别是如何频繁的灾难发生作为一个函数的浓度的聚合#945;#946;微管蛋白亚基。这项研究将结合联合收割机的各种方法，包括预测计算模拟，使用机制特异性位点定向突变的#945;#946;-微管蛋白，并在体外生物化学和重建。使用这套工具，我们将（i）将三种不同的生物化学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的预测;（ii）对微管晶格中的邻居耦合进行实验测试，这是假设发生的，但以前无法测试;和（iii）测量在#945;-和#946;-微管蛋白中保守的残基相互作用三联体的突变如何&&影响微管聚合动力学和微管内外的αβ-微管蛋白的构象。总之，这些方法将解决悬而未决的问题微管dynamics.This项目的基本机制是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和功能集群共同资助。

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.