COLLABORATIVE RESEARCH: Establishing the microtubule-actin crosstalk in the preprophase band by the rice kinesin OsKCH2

该项目研究调节水稻植物细胞分裂和生长的基本机制，预计将产生广泛的社会影响。首先，该项目的发现将影响未来的水稻育种，而水稻养活了世界一半的人口。第二，俄勒冈州州立大学和位于戴维斯的加州大学的年轻科学家将通过参与以发现为导向的研究，在多学科领域接受培训。第三，该项目包含基于光学显微镜的短期课程和为服务不足的学生提供的实践培训机会，这将激发他们对STEM学科的兴趣。此外，为了提高公众对前沿研究项目的认识，将在面向高中和社区大学科学教师的高级光学显微镜讲习班中，以植物运动蛋白为实例，研究水稻中的植物特异性驱动蛋白OsKCH 2，使微管（MT）和丝状肌动蛋白（F-肌动蛋白）之间的串扰在皮层分裂网站和它如何调节细胞分裂。驱动蛋白是利用ATP水解产生的能量为许多基本细胞过程提供动力的马达蛋白，例如沿着MT运输货物和组织/重塑生理上重要的基于MT的阵列。OsKCH 2属于高等植物中具有钙调蛋白同源结构域（KCH）的驱动蛋白。已知KCH在体外交联MT和F-肌动蛋白，但它们在植物生长和发育中的功能仍然知之甚少。该项目基于几个关键的初步发现，包括：（1）OsKCH 2的突变导致侏儒表型，（2）OsKCH 2在有丝分裂早期与PPB特异性相关，（3）OsKCH 2在体外直接结合并转运微管上的F-肌动蛋白，以及（4）OsKCH 2是第一个以单一二聚体形式表现出进行性运动的负末端定向驱动蛋白-14。 本项目将采用多学科的方法来解决两个目标：（1）使用体外单分子成像来剖析OsKCH 2进行运动的调控机制，以及（2）通过检查与无效kch 2突变相关的表型来询问OsKCH 2在细胞分裂和植物生长中的体内功能。

This project studies the fundamental mechanisms that regulate cell division and growth of the rice plant and is expected to have a broad spectrum of societal impacts. First, findings from this project will impact future breeding of rice, which feeds half of the world's population. Second, young scientists at both Oregon State University and University of California in Davis will be trained in multi-disciplinary areas by participating in the discovery-oriented research. Third, this project contains light microscopy-based short courses and hands-on training opportunities for underserved students, which will stimulate their interests in STEM disciplines. In addition, to increase public awareness of cutting-edge research programs, plant motor proteins will be included as living examples in advanced light microscopy workshops for high school and community college science teachers.Specifically, this project is aimed at investigating how OsKCH2, a plant-specific kinesin in the rice plant Oryza sativa, enables the crosstalk between microtubules (MTs) and filamentous actins (F-actins) at the cortical division site and how it regulates cell division. Kinesins are motor proteins that use the energy from ATP hydrolysis to power numerous essential cellular processes such as transporting cargos along MTs and organizing/remodeling physiologically important MT-based arrays. OsKCH2 belongs to the group of Kinesins with a Calponin Homology domain (KCHs) in high plants. KCHs are known to crosslink MTs and F-actin in vitro, but their functions in plant growth and development remain poorly understood. The project is based on several critical preliminary findings including: (1) mutations in OsKCH2 caused a dwarfism phenotype, (2) OsKCH2 is specifically associated with the PPB during early stages of mitosis, (3) OsKCH2 directly binds to and transports F-actin on microtubules in vitro, and (4) OsKCH2 is the first minus end-directed Kinesin-14 to demonstrate processive motility as a single dimer. This project will use a multi-disciplinary approach to address two objectives: (1) dissecting the regulatory mechanism underlying the processive motility of OsKCH2 using in vitro single-molecule imaging, and (2) interrogating the in vivo functions of OsKCH2 in cell division and plant growth by examining phenotypes linked to a null kch2 mutation.