Swarming motility and the regulation of flagellar biosynthesis in Bacillus subtilis

摘要 许多细菌通过合成螺旋状的鞭毛来运动，当旋转时， 通过环境。每一种细菌合成一种特定数量的鞭毛， 鞭毛在细胞表面的物种特异性模式。鞭毛是复杂的纳米机器 几十种不同的蛋白质，以及每种细菌如何控制鞭毛的数量和模式是很差的- 明白此外，当细胞接触固体表面时，每个细胞的鞭毛数量增加， 启动一种叫做群集的表面运动。卡恩斯实验室使用经典的正向遗传学，超级- 分辨率显微镜和生物化学研究鞭毛生物合成和群集运动的革兰氏 阳性菌枯草芽孢杆菌。该项目的目标是了解鞭毛的生物合成在 不断增长的细胞结构的背景下。首先，我们将确定鞭毛数量是如何控制的差- 了解鞭毛生物合成的主调节因子SwrA和响应调节因子DegU。二是 探索表面接触反应如何被转导以抑制衔接子介导的调节性蛋白水解 并增加鞭毛数量。第三，我们将学习如何鞭毛杆插入通过 肽聚糖的发生，以及如何控制杆长度以匹配肽聚糖的厚度。四、鞭毛 在一个网格状的模式合成，我们将研究如何鞭毛图案的解释和更新， 细胞生长期间的时间，并与肽聚糖插入协调。最终，我们希望实现一个全面的 了解细胞如何在特定位置动态控制鞭毛生物合成的起始， 把机器插进牢房我们的基础研究是细胞如何自我组织和 适用于时空控制的组装transenvelope纳米机器参与 致病机制包括鞭毛、皮利和分泌系统如注射体。

ABSTRACT Many bacteria are motile by synthesizing corkscrew-like flagella which when rotated propel bacteria through the environment. Each bacterium synthesizes a species-specific number of flagella and inserts the flagella in a species-specific pattern on the cell surface. Flagella are complex nanomachines assembled from dozens of different proteins and how each bacterial species controls flagellar number and patterning is poorly- understood. Moreover, the number of flagella per cell increases when cells come into contact a solid surface to initiate a form of surface motility called swarming. The Kearns lab uses classical forward genetics, super- resolution microscopy, and biochemistry to study flagellar biosynthesis and swarming motility of the Gram positive bacterium Bacillus subtilis. The goals of the project are to understand flagellar biosynthesis in the context of growing cell architecture. First, we will determine how flagellar number is controlled by the poorly- understood master regulator of flagellar biosynthesis SwrA and a response regulator DegU. Second, we will explore how the surface contact response is transduced to inhibit the adaptor-mediated regulatory proteolysis of SwrA and increase flagellar number. Third, we will learn how the flagellar rod insertion through peptidoglycan occurs, and how rod length is controlled to match the thickness of peptidoglycan. Fourth, flagella are synthesized in a grid-like pattern and we will study how flagellar patterning is interpreted and updated in time during cell growth, and coordinated with peptidoglycan insertion. Ultimately, we want to achieve a holistic understanding of how a cell dynamically governs the initiation of flagellar biosynthesis at specific locations to insert the machine through the cell envelope. Our basic research is fundamental to how cells self-organize and is applicable to the spatiotemporal control of the assembly of transenvelope nanomachines involved in pathogenesis including flagella, pili and secretion systems like the injectisome.