Transitions to Excellence: Structural Cell Biology of Kinesin Motor Proteins

我们体内几乎所有的细胞都含有微型的细胞高速公路，被称为微管细胞骨架，它被用作细胞内物质运输的轨道。这些结构也有助于驱动细胞运动，并形成在细胞分裂过程中分离遗传物质所必需的机制。与道路的刚性水泥基础不同，蜂窝高速公路的独特之处在于，它们的刚性足以支撑比其大小大一百倍的材料的移动，但它们是动态的，可以在几秒钟内重新组织。该项目研究了细胞马达如何在细胞高速公路上移动并控制它们的重组，这将为细胞中的细胞骨架调节提供基本的新见解。该项目还将通过培训和指导本科生和高中生，包括来自IU赞助的多个项目的URM学生，产生更广泛的影响。分子运动蛋白的研究为学生提供了一个理想的学习工具，除了学习数据收集，分析和展示的科学过程外，还可以在分子尺度上真正“看到”科学的作用。此外，该项目将在两个IU赞助的研究项目中为本科生开发一个新的职业指导计划，以帮助学生在大学早期阶段进行职业选择，并扩大他们对STEM职业的参与。沿着微管行走的分子动力蛋白是酶家族的一部分，称为运动蛋白，它们共享一个保守的催化结构域，用于沿着微管行走，以及一个非催化尾结构域，决定它们在细胞中的作用的特异性。本项目旨在阐明控制尾部结合特异性调节的机制。虽然细胞生物学方法可以揭示马达在哪里起作用，生化方法可以表明它与哪些蛋白质结合以及紧密程度，但通过结构研究可以最好地实现详细的分子理解，这将阐明不同的马达和尾部结构域是如何沿着微管晶格组织的。对微管结构的理解已经被低温电子显微镜领域的最新进展所改变。该项目将利用低温电子显微镜来解决单个马达马达的马达和非马达尾域如何与微管相互作用，并将测试一个保守调节器如何调节多个马达尾域的结合。此外，该项目将为高级细胞生物学家提供低温电子显微镜的合作培训，以通过实施这项强大的技术来扩展他们的研究计划。这些研究将为理解微管结构如何影响分子马达的动力学和运输特性提供新的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nearly all cells in our bodies contain miniaturized cellular highways, known as the microtubule cytoskeleton, that are used as tracks for transport of material inside cells. These structures also help drive cell movement and form the machinery necessary to segregate the genetic material during cell division. Unlike the rigid cement foundation of a roadway, cellular highways are unique in that they are rigid enough to support movement of material that is a hundred times its size, and yet they are dynamic and can be reorganized in a matter of seconds. This project addresses how cellular motors both move on the cellular highways and control their reorganization, which will provide fundamental new insights into cytoskeletal regulation in cells. This project will also have broader impacts through training and mentoring of both undergraduate students and high-school students, including URM students from multiple IU sponsored programs. The study of molecular motor proteins provides an ideal learning tool for students to literally “see” science in action at the molecular scale in addition to learning about the scientific process of data collection, analysis and presentation. In addition, this project will develop a new career mentoring program for undergraduate students in two IU sponsored research programs to help students navigate career choices at an earlier stage of college and broaden their participation in STEM careers.Molecular motor proteins that walk along the microtubules are part of families of enzymes, called kinesins, that share a conserved catalytic domain used to walk along the microtubule and a non-catalytic tail domain that determines specificity of their action in cells. This project seeks to elucidate the mechanisms that control the regulation of tail binding specificity. While cell biological approaches can uncover where a motor acts, and biochemical approaches can indicate which proteins it binds to and how tightly, a detailed molecular understanding can best be achieved through structural studies that will elucidate how different motor and tail domains are organized along the microtubule lattice. Structural understanding of the microtubule has been transformed by recent advances in the field of cryo-electron microscopy. The project will utilize cryo-electron microscopy to address how motor and non-motor tail domains of a single kinesin motor interact with the microtubule and will test how a conserved regulator modulates binding of multiple motor tail domains. In addition, this project will provide collaborative training in cryo-electron microscopy for a senior level cell biologist to expand their research program through the implementation of this powerful technology. These studies will provide new insights into understanding how microtubule structure impacts both dynamics and transport properties of molecular motors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.