Flavobacterium Gliding Motility:From protein secretion to cell surface movements

黄杆菌滑动运动：从蛋白质分泌到细胞表面运动

• 批准号: 1516990
• 负责人: Mark McBride
• 金额: $ 62万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1516990&HistoricalAwards=false
• 关键词: Flavobacterium; Gliding; Motility; protein; secretion

Gliding motility is a form of movement by which certain bacteria commonly found both inside and on the surface of the body are able to move themselves over solid surfaces. Gliding motility relies on an apparatus composed of unique proteins and this project will explore two fundamental cellular processes (protein secretion and cell movement) and the interactions between them that underlie gliding motility. Graduate and undergraduate students as well as postdoctoral fellows will be actively engaged in the project, and will gain experience in interdisciplinary research involving genetics, molecular biology, and microscopic and mathematical modeling. They will also receive training in scientific writing and presentation. Results of the project will be reported by students at national meetings and published in the scientific literature, and genetic tools that are developed will be made available to the scientific community. Results of this research will be incorporated into undergraduate laboratory exercises and public lectures will be presented to convey the excitement of scientific discovery. The research will address 3 specific aims related to the functioning of the type IX secretion system (T9SS) responsible for delivering surface adhesin SprB which is responsible for the gliding motility apparatus. The goals are: (1) to characterize using biochemical and genetic approaches the mechanism by which secreted proteins are targeted to the T9SS; (2) to define the moving components of the motility machinery by fusing fluorescent proteins to components of the motility apparatus to identify those that move rapidly over long distances (mathematical analyses of these movements will be used to construct models to explain gliding); and (3) to distinguish between the T9SS and the gliding motility apparatus to determine which proteins function primarily in secretion, in motility, or in both processes. This will help determine if the T9SS and the gliding motility apparatus are two independent machines or different aspects of a single machine. Cells with mutations in T9SS genes will be examined to determine if they retain gliding motor function. Mutations that result in defects in either motility or secretion, but not both, will be isolated and analyzed to determine which proteins function primarily in secretion and which function in motility. Comparative analysis of the F. johnsoniae and Cellulophaga algicola T9SSs and their respective gliding machines will identify conserved features and highlight the roles of individual proteins in secretion or motility. The bacteria studied belong to the understudied phylum, Bacteroidetes. Bacteriodetes is one of the largest bacterial phyla where the proteins that make up the T9SS and the gliding motility apparatus are common. However, these proteins are not found in other groups of bacteria. A more complete understanding of the T9SS and the gliding machinery will expand our understanding of mechanisms of bacterial protein secretion, dynamic protein movements within cells, and cell movements over surfaces.

滑动运动是一种运动形式，通过这种运动，体内和表面上常见的某些细菌能够在固体表面上移动。滑行运动依赖于由独特蛋白质组成的装置，该项目将探索两个基本的细胞过程(蛋白质分泌和细胞运动)以及它们之间的相互作用，它们是滑行运动的基础。研究生和本科生以及博士后研究员将积极参与该项目，并将在涉及遗传学、分子生物学、微观和数学建模的跨学科研究方面获得经验。他们还将接受科学写作和演讲方面的培训。该项目的结果将由学生在全国会议上报告并发表在科学文献上，开发的基因工具将向科学界提供。这项研究的结果将被纳入本科生的实验室练习，并将举行公开讲座，以传达科学发现的兴奋。这项研究将解决与IX型分泌系统(T9SS)的功能相关的3个具体目标，T9SS负责输送表面粘附素SprB，该系统负责滑行运动装置。目标是：(1)利用生化和遗传学方法表征分泌蛋白质靶向T9SS的机制；(2)通过将荧光蛋白与运动装置的部件融合来确定运动机械的运动部件，以确定哪些运动部件在长距离快速移动(这些运动的数学分析将被用来构建解释滑动的模型)；以及(3)区分T9SS和滑动运动部件，以确定哪些蛋白质主要在分泌、运动或这两个过程中发挥作用。这将有助于确定T9SS和滑翔运动装置是两台独立的机器还是一台机器的不同方面。将对T9SS基因突变的细胞进行检查，以确定它们是否保留了滑动运动功能。导致运动性或分泌性缺陷的突变，但不是两者都有，将被分离和分析，以确定哪些蛋白质主要在分泌中发挥功能，哪些在运动性中发挥功能。对强氏华支睾吸虫和藻噬细胞T9SS及其各自的滑翔机的比较分析将确定保守的特征，并突出单个蛋白质在分泌或运动中的作用。所研究的细菌属于未被研究的类杆菌门。类杆菌是最大的细菌门之一，其中组成T9SS和滑行运动装置的蛋白质是常见的。然而，这些蛋白质在其他细菌群体中没有发现。对T9SS和滑动机制的更全面的了解将扩大我们对细菌蛋白质分泌机制、细胞内动态蛋白质运动以及细胞表面运动的理解。