Studies on Microtubule Binding Proteins

描述（由申请人提供）：运动蛋白沿着微管移动或从末端解聚。在过去的12年里，我们使用冷冻电子显微镜和图像分析来研究这些运动和解聚活性。基于我们的发现，以及许多其他实验室的工作，我们概述了设计原则，这些原则统一了我们对运动蛋白和肌凝蛋白的思考，并为这两个分子马达超家族的机制理解提供了一个总体框架。我们现在对核苷酸介导的构象变化有了一个很好的总体理解，这些构象变化是由传统的激酶蛋白的进程性、正端定向运动、激酶蛋白14的非进程性、负端定向运动以及激酶蛋白13介导的解聚的许多方面引起的。对微管相关蛋白的进一步研究为这些蛋白选择性稳定微管的机制提供了新的见解。我们过去的结果为现在的提议奠定了基础。这里描述的实验分为两大主题领域。首先，我们描述了一些实验，这些实验将回答我们所看到的一些关于运动蛋白介导的运动和解聚的悬而未决的一般问题。其次，我们在MAPs研究的基础上，扩展了这方面的研究计划，并结合对微管加末端跟踪蛋白和着丝点复合物的研究，以研究微管动力学和染色体-微管附着调节的结构基础。在我们所有的工作中，我们寻求回答基本的生物学问题，我们的发现对健康和患病状态都有相关性。

DESCRIPTION (provided by applicant): Kinesins move along microtubules or depolymerize them from the ends. Over the last 12 years, we have used cryo-electron microscopy and image analysis to investigate these motility and depolymerization activities. Based on our findings, as well as work from many other laboratories, we have outlined design principles that unify our thinking about kinesins and myosins and provide a general framework for a mechanistic understanding of these two superfamilies of molecular motors. We now have a good general understanding of the nucleotide-mediated conformational changes underlying processive, plus-end-directed motion by conventional kinesin, non-processive, minus-end-directed motion by kinesin 14s, and many aspects of kinesin 13-mediated depolymerization. Additional work on microtubule associated proteins has provided insights into the mechanisms of selective microtubule stabilization by these proteins. Our past results set the stage for the current proposal. The experiments described here fall into two broad subject areas. First, we describe experiments that will answer what we see as some of the remaining outstanding general questions about kinesin-mediated motility and depolymerization. Second, we build upon our investigations on MAPs, expanding this aspect of our research program and incorporating studies on microtubule plus-end-tracking proteins and kinetochore complexes to investigate the structural basis for modulation of microtubule dynamics and chromosome-microtubule attachments. In all our work, we seek to answer fundamental biological questions and our findings have relevance for both the healthy and diseased states.