Molecular mechanisms of physical interactions between bacteria and their surroundings

项目摘要 为了在不同的环境中生存，细菌必须动态地与他们的物理环境相互作用才能感知 并将刺激融入生理反应中。细菌经常在细胞外实现这种相互作用 通过使用表面暴露的纳米机器将细胞内空间连接到 细胞表面。分布最广的表面暴露的纳米机器是称为IV型附件的 菌毛(T4P)和进化上相关的结构，据信是从古代纳米机器分化而来的 发现于最后一个宇宙共同祖先。T4P是高度动态的，采用多个分子马达来 伸展和收缩的动力循环对许多行为都是必不可少的，使它们成为 了解细胞与其物理环境之间的动态交换。尽管他们的范围广泛 在许多生物过程中的分布和重要性，人们对背后的基本生物学知之甚少 T4P的动力、调节和结构。我们将结合遗传学、细胞生物学、生物物理学和 生化技术，解剖T4P的基础生物学。我们将采用多种模式生物 包括新月形杆菌、霍乱弧菌和不动杆菌，它们都能产生T4P用于 跨不同T4P的比较生物学方法。我们以前在这些系统中工作的经验和专业知识 将使我们能够询问T4P调节机制如何演变以响应环境刺激和 这些监管差异是如何影响行为产出的。我们的五年目标包括了解 驱动T4P动态的基本机制，如何调节动态，以及不同 细菌行为和生理的调节机制。这项工作将解决几个关键问题， 包括：1)影响动力学的主要因素是什么？2)控制亚细胞定位的机制是什么 花纹呢？T4P的结构亚基是如何决定其功能和力学性能的 来影响不同的行为产出？这项工作将提供对T4P监管和动态的重要洞察 这将导致更好地理解细胞与其环境之间的物理相互作用，并 使开发的工具能够在它们引发的广泛细菌行为中阻碍或控制T4P的功能。这个 通过我们对T4P的研究所取得的基本发现也将揭示生物学的一般方面，包括 深入了解分子马达的基本机制，即控制细胞内空间的机制 组织，以及蛋白质结构和功能之间的关系。

Project Summary To survive in diverse environments, bacteria must dynamically interact with their physical surroundings to sense and incorporate stimuli into physiological responses. Bacteria often achieve this interplay between extracellular cues and intracellular signaling by using surface-exposed nanomachines that connect the intracellular space to the cell surface. The most broadly distributed surface-exposed nanomachines are appendages called type IV pili (T4P) and evolutionarily related structures that are believed to have diverged from an ancient nanomachine found in the last universal common ancestor. T4P are highly dynamic, employing multiple molecular motors to power cycles of extension and retraction that are essential for many behaviors, making them an ideal system for understanding the dynamic exchange between cells and their physical environments. Despite their broad distribution and importance in many biological processes, little is known about the fundamental biology behind T4P dynamics, regulation, and structure. We will use a combination of genetics, cell biology, biophysics, and biochemical techniques to dissect the fundamental biology of T4P. We will employ multiple model organisms including Caulobacter crescentus, Vibrio cholerae, and Acinetobacter species that all produce T4P for a comparative biology approach across different T4P. Our prior experience and expertise working in these systems will enable us to interrogate how T4P regulatory mechanisms evolve to respond to environmental stimuli and how these regulatory differences influence behavioral outputs. Our five-year goals include understanding the basic mechanisms driving T4P dynamics, how dynamics are regulated, and the consequences of different regulatory mechanisms on bacterial behavior and physiology. This work will address several key questions, including: 1) what are the main factors influencing dynamics? 2) what mechanisms control subcellular localization and patterning? And 3) how do structural subunits of T4P determine their functional and mechanical properties to influence diverse behavioral outputs? This work will provide critical insight into T4P regulation and dynamics that will result in better understanding of the physical interactions between cells and their environments and enable the development of tools to hinder or control T4P function in the broad bacterial behaviors they elicit. The fundamental discoveries made through our study of T4P will also reveal general aspects of biology including insight into the underlying mechanics of molecular motors, the mechanisms controlling intracellular spatial organization, and the relationship between protein structure and function.