Identifying the mechanisms of mechanosensing by the bacterial flagellar motor

项目总结/摘要 以生物膜或菌群形式的表面定殖是自由游动细菌的第一步， 许多细菌感染，但细菌如何感觉表面仍然未知。细菌鞭毛马达 成为表面传感领域的关键人物。传统上被认为只参与运动，通过旋转螺旋 新的证据表明，马达作为机械传感器来感知细菌表面 交互.然而，运动介导的机械感知途径的组分在很大程度上仍然存在， 身份不明为了开发有效的策略来预防和处理有害生物膜，迫切需要 了解马达如何感知力并将信息传递给下游过程。客观 该提议的目的是表征运动介导的机械感测及其相关电路的功能。 拟议的工作将利用新的生物物理方法来精确控制作用在 发动机，并测量发动机的响应。先前的结果和初步数据表明， 通过扭矩产生定子单元的动态自组装改变其扭矩输出来加载， 一种可能的机械感受机制在信号转导方面，目前还不清楚 机械感测信息从马达传递到生物膜形成途径， 由细菌第二信使环二鸟苷酸（c-di-GMP）。核心假设是， 运动的刺激激活触发c-di-GMP信号传导的局部和整体反应。中央 将通过实验表征运动机械感受和使用高通量的 遗传学来描绘机械转导途径。这些目标将利用生物物理， 成像、分子和基因组工具。这项工作的预期成果是更好地了解如何 细菌的鞭毛马达参与表面传感。长期目标是研究细菌如何产生 复杂的行为。本次职业发展奖的培训阶段 概述了获取技术和专业技能的全面计划， 转变为独立研究岗位。该项目的成功完成将提供一个平台 未来的研究旨在揭示分子相互作用和潜在的物理生物学， 复杂的细菌行为，如生物膜形成。

PROJECT SUMMARY/ABSTRACT Surface colonization in the form of biofilms or swarms by otherwise free-swimming bacteria is the first step in many bacterial infections, but how bacteria sense surfaces remains unknown. The bacterial flagellar motor has emerged as a key player in surface sensing. Seen traditionally as involved only in motility by rotating helical filaments, new evidence suggests that the motor acts as a mechanosensor to sense bacterial surface interactions. However, the components of the motor-mediated mechanosensing pathway largely remain unidentified. To develop effective strategies for preventing and treating harmful biofilms, there is a critical need to understand how the motor senses forces and transmits information to downstream processes. The objective of this proposal is to characterize the function of motor-mediated mechanosensing and its associated circuitry. The proposed work will utilize novel biophysical methods to precisely control the mechanical load acting on the motor and to measure the motor’s response. Previous results and preliminary data show that the motor adapts to load by changing its torque output via the dynamic self-assembly of torque-generating stator units, providing a possible mechanism for mechanoreception. On the signal transduction side, it is unclear how the mechanosensing information is transmitted from the motor to the biofilm formation pathways, which are regulated by the bacterial second messenger cyclic diguanylate (c-di-GMP). The central hypothesis is that mechanical stimulation of the motor activates local and global responses that trigger c-di-GMP signaling. The central hypothesis will be tested by experimentally characterizing motor mechanoreception and using high-throughput genetics to delineate the mechano-transduction pathways. These goals will utilize a combination of biophysical, imaging, molecular, and genomic tools. The expected outcome of this work is an improved understanding of how the flagellar motor of bacteria is involved in surface sensing. The long-term goal is to study how bacteria generate complex behaviors using simple molecular machinery. The training phase of this career development award outlines a comprehensive plan for the acquisition of technical and professional skills that will enable the PI’s transition into an independent research position. The successful completion of this project will provide a platform for future research aimed at revealing the molecular interactions and the underlying physical biology that enable complex bacterial behavior such as biofilm formation.