Microtubule Organization by Kinesin-12 in the Phragmoplast

Phragmoplast 中的 Kinesin-12 微管组织

• 批准号: 0920454
• 负责人: Bo Liu
• 金额: $ 59.73万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0920454&HistoricalAwards=false
• 关键词: Microtubule; Organization; Kinesin; 12; Phragmoplast

Intellectual merits. This project is devoted to understanding cell division mechanisms in plants. Plant cells divide by laying down a physical barrier called the cell plate between two daughter nuclei. In order to achieve this goal, organisms of advanced green algae and land plants have developed a common cytokinetic apparatus named the phragmoplast which is a key evolutionary landmark. The phragmoplast is established by a framework of the cytoskeletal element of microtubules, which are aligned perpendicularly to the future cell plate. Microtubules are dynamic polar filaments with their plus ends exhibiting more rapid growth capability than their minus ends. Phragmoplast microtubules are organized into a bipolar array with their plus ends located at or near the division site. Vesicles generated by the Golgi apparatus are transported toward microtubule plus ends, resulting in the assembly of the cell plate. How microtubules are organized into this highly ordered form is the central question being addressed in this project for the next three years. A number of studies suggest that microtubule-associated proteins and the microtubule-based motor kinesins are critical players for microtubule organization in the phragmoplast. We have been using the cress plant Arabidopsis thaliana as a model for our studies, and have discovered that three Kinesin-12 members of the kinesin superfamily exclusively appear at microtubule plus ends in the developing phragmoplast, and play a critical role in microtubule organization. The planned studies are aimed at testing the hypothesis that the Kinesin-12 motors and their binding proteins form a motor complex to regulate the bipolar organization of phragmoplast microtubules. In order to test this hypothesis, the first objective is to apply genetic approaches to dissect how the three Kinesin-12 motors work together in the phragmoplast. The second objective is to understand functions of two Kinesin-12-binding proteins by using biochemical, cell biological, and genetic tools. The last objective focuses on understanding how the function of Kinesin-12 is linked to that of the microtubule-associated protein MAP65-3. Discoveries to be made are going to provide a protein-protein interactive picture at microtubule plus ends in the phragmoplast.Broader impacts. In this project, the use of the model organism Arabidopsis thaliana will bring insights into molecular mechanisms that are responsible for the invention of the phragmoplast during the evolution toward land plants. Experimental results will be made public by journal publications. They will also be translated into lecture materials to reach 250+ undergraduate students in a Cell Biology class taught each year by the Principal Investigator of this project. In the meantime, the participating graduate student receives interdisciplinary training in areas of biochemistry, cell biology and genetics. In addition, the project engages high school students and undergraduate students by providing them with hands-on research experience in the laboratory. By directly contributing to discoveries, these students share the excitement that could inspire them to pursue a career in science.

智力优点。该项目致力于了解植物中的细胞分裂机制。植物细胞通过在两个子核之间放置一个称为细胞板的物理屏障来分裂。为了实现这一目标，先进的绿藻和陆地植物的生物已经开发出一种名为Phragmoplast的常见的细胞动物仪，这是关键的进化地标。 Phragmoplast是通过微管的细胞骨架元素的框架建立的，该框架垂直于未来的细胞板对齐。微管是动态的极性丝，其加上末端的生长能力比减去末端更快。将短片微管组织成一个躁郁症阵列，其正端位于分裂部位或附近。由高尔基体产生的囊泡转运到微管和末端，从而导致细胞板的组装。在接下来的三年中，该项目将如何将微管组织到这种高度有序的形式中。许多研究表明，与微管相关的蛋白质和基于微管的运动驱动力是Phragmoplast中微管组织的关键参与者。我们一直在使用Cress Plant拟南芥作为我们的研究模型，并发现三个驱动蛋白12个超家族成员独家出现在Microtubule Plus Plus末端，并在发育中的Phragmoplast中终结，并且在微管组织中起着至关重要的作用。计划的研究旨在检验以下假设：驱动蛋白-12电动机及其结合蛋白形成运动复合物，以调节Phragmoplast微管的双极组织。为了检验这一假设，第一个目标是采用遗传方法来剖析三种动力蛋白12电动机在Phragmoplast中如何共同工作。第二个目标是通过使用生化，细胞生物学和遗传工具来了解两种驱动蛋白12结合蛋白的功能。最后一个客观的重点是了解驱动蛋白-12的功能如何与微管相关蛋白MAP65-3的功能联系在一起。要做出的发现将在phragmoplast.boader撞击中提供微管和末端的蛋白质蛋白质互动图片。在这个项目中，使用模型生物拟南芥的使用将带来分子机制的见解，这些机制是负责在向土地植物进化过程中Phragmoplast发明的。实验结果将由期刊出版物公开。他们还将被翻译成讲座材料，以吸引该项目的主要研究人员每年教授的细胞生物学课程中的250多名本科生。同时，参与的研究生接受了生物化学，细胞生物学和遗传学领域的跨学科培训。此外，该项目通过为实验室提供动手研究经验来吸引高中生和本科生。通过直接为发现做出贡献，这些学生分享了激发他们从事科学职业的兴奋。