Self-Coordination of Dyneins during Ciliary Beating

本研究的目的是阐明纤毛运动自协调振荡的分子机制。 运动纤毛是鞭子一样的结构，像刚毛一样从细胞表面突出，并产生周期性的跳动波形。 纤毛的跳动为精子和许多小生物的游动提供动力。纤毛跳动还在肠和肺中产生流体流动，并介导细胞信号传导。 纤毛的核心结构成分是轴丝，它有一个由九个外部微管组成的环，围绕着两个中心微管。 详细调查的机制，权力自我协调纤毛跳动将显着有助于我们了解如何睫状体功能障碍与一组缺陷，称为ciliopathies。 该项目的更广泛影响还将有助于为加州奥克兰代表性不足群体的高中生建立教育推广计划。 为了吸引新一代的科学，夏季研究机会，研讨会和科学博览会将在当地公立学校组织。本科生将通过积极参与研究为项目做出贡献。这项研究的结果将被整合到一个新的课程中，该课程将为希望从事生命科学研究生职业的物理学本科生开发。纤毛跳动的基本原理依赖于微管和两种不同类型的动力蛋白马达蛋白（内臂和外臂动力蛋白）之间的滑动运动。 为了使纤毛中的微管局部弯曲，轴丝一侧的动力蛋白必须是活性的，而另一侧的动力蛋白则是非活性的。 这些状态必须周期性地切换，以使弯曲沿着轴丝的长度传播。 负反馈机制，协调跨轴丝动力蛋白马达的活动仍有待确定。 为了阐明调节纤毛跳动的机制，本项目将测试四膜虫内臂和外臂动力蛋白在体外的机械性能的几个预测。 利用单分子荧光和操纵方法，该项目将完成三个目标。 它将确定动力蛋白单体在马达滑动微管细丝时相对于彼此步进的机制。 它将研究动力蛋白马达在大型团队中运作时的涌现特性。 该项目还将重建纤毛振荡的最小系统，并可视化单个微管的运动。 该项目的成功完成将揭示内臂和外臂动力蛋白协调的新分子机制，并确定运动纤毛自我协调振荡的最低要求。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

The goal of this project is to elucidate the molecular mechanism of self-coordinated oscillations of motile cilia. Motile cilia are whip-like structures that protrude like bristles from the cell surface and generate a periodic beating waveform. Ciliary beating powers the swimming of sperm and many small organisms. Ciliary beating also generates fluid flow in the intestines and lungs, and mediates cell signaling. The core structural component of a cilium is the axoneme, which has a ring of nine outer microtubule doublets surrounding two central microtubules. A detailed investigation of the mechanism that powers self-coordinated ciliary beating will significantly contribute to our understanding of how ciliary malfunction is linked to a group of defects known as ciliopathies. The Broader Impacts of this Project will also help establish educational outreach programs for high school students from underrepresented groups in Oakland, CA. To attract a new generation to science, summer research opportunities, seminars and science fairs will be organized in local public schools. Undergraduate students will contribute to the Project by actively participating in the research. The results of the proposed research will be integrated into a new curriculum that will be developed for Physics undergraduates wishing to pursue a graduate career in the life sciences.The basic principle of ciliary beating relies on a sliding motion between microtubules and two different types of dynein motor proteins, the inner arm and the outer arm dyneins. To bend microtubules locally in cilia, dyneins on one side of an axoneme must be active while those on the opposite side are inactive. These states must switch periodically to propagate bending along the length of the axoneme. The negative feedback mechanisms that coordinate the activities of dynein motors across an axoneme remain to be determined. To elucidate the mechanisms that regulate ciliary beating, this project will test several predictions for the mechanical properties of Tetrahymena inner- and outer-arm dyneins in vitro. Using single-molecule fluorescence and manipulation methods, the project will complete three goals. It will determine the mechanism by which dynein monomers step relative to each other as the motor slides microtubule filaments. It will investigate the emergent properties of dynein motors when functioning in large teams. The project will also reconstitute a minimal system for ciliary oscillations and visualize the movement of individual microtubules. The successful completion of this project will reveal new molecular mechanisms of inner-arm and outer-arm dynein coordination and determine minimum requirements for self-coordinated oscillations of motile cilia.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.