Probing the molecular interactions and architecture of bacterial cell division proteins

在过去的几年里，细胞微生物学在一定程度上受到成像技术进步的推动，出现了复兴。我们深入细胞内观察基本过程中所涉及的大分子复合体的定位和组织的能力，促进了我们对细菌如何运动、结合和分裂的理解。在革兰氏阴性细菌中，一组被称为分裂体的蛋白质驱动内膜和外膜同步内陷，并在新形成的隔膜合成肽聚糖。分裂体蛋白形成多组分的Z-环结构，主要由微管蛋白同源物FtsZ组成。FtsZ细丝的形成动力学被认为是正确组装Z环的关键。在大肠杆菌中，约有10种必需蛋白和20多种非必需蛋白参与分裂体组装。相互作用以一种分层的方式发生，所提出的细胞分裂机制可以分为三个不同的阶段-早期、中期和晚期。尽管细菌细胞分裂已经在细胞和分子水平上进行了数十年的深入研究，许多关键的蛋白质参与者已经确定，但关于控制分裂体形成和动力学的分子机制和蛋白质相互作用仍然存在关键问题。本研究计划旨在阐明涉及Z-环稳定性和动力学的蛋白质相互作用和大分子结构。具体地说，我们将识别和表征FtsZ和Zap蛋白家族的相互作用和大分子结构。这些相互作用对早期细胞分裂至关重要，ZAP蛋白的重叠功能被认为与Z-环介导的隔膜有关。我们还将确定中期细胞分裂中的蛋白质相互作用，该相互作用决定了FtsK是如何将细胞质分裂与隔膜和细胞壁凹陷联系起来的。FtsK是一种重要的细胞分裂“检查点”蛋白质。我们将使用生化、分子和尖端成像工具的原创组合来解决这些问题，这将导致细胞分裂方面的突破性进展。这项研究计划的长期愿景是在细菌细胞分裂的所有不同阶段建立一个完整的生化和结构图，从而阐明驱动这一基本过程的机制。我们的发现和我们开发的方法将超越原核细胞生物学，并将适用于不同的生物系统。

Cellular microbiology has seen a renaissance in the past several years, spurred in part by advances in imaging techniques. Our ability to peer into cells to see the localization and organization of macromolecular complexes involved in fundamental processes has advanced our understanding of how bacteria move, associate and divide. In gram-negative bacteria, a group of proteins known as the divisome drives the synchronized invagination of the inner and outer membranes and peptidoglycan synthesis at the newly formed septum. Divisome proteins form the multicomponent Z-ring structure, which is primarily composed of the tubulin homologue FtsZ. The dynamics of FtsZ filament formation are considered essential for proper Z-ring assembly. In Escherichia coli, ~10 essential and over 20 nonessential proteins are involved in divisome assembly. Interactions occur in a hierarchical manner, and the proposed mechanisms of cell division can be divided into three distinct stages - early, intermediate and late. Although bacterial cell division has been intensively studied at the cellular and molecular levels for decades, with many of the key protein players identified, critical questions remain about the molecular mechanisms and protein interactions that govern the formation and dynamics of the divisome. ***This research program aims to elucidate the protein interactions and macromolecular structures involved in Z-ring stability and dynamics. Specifically, we will identify and characterize the interactions and macromolecular architecture of FtsZ and the Zap family of proteins. These interactions are critical for early-stage cell division, and the overlapping functions of the Zap proteins have been implicated in Z-ring-mediated septation. We will also determine the protein interactions in intermediate-stage cell division that govern how FtsK, an essential cell division `checkpoint' protein, links division of the cytoplasm with septation and cell wall invagination. We will address these questions using an original combination of biochemical, molecular and cutting-edge imaging tools, which will lead to groundbreaking advances in cell division. The long-term vision for this research program is to develop a complete biochemical and structural picture of bacterial cell division during all of its distinct stages, thereby elucidating the mechanisms that drive this essential process. Our findings and the approaches we develop will transcend prokaryotic cell biology and will be applicable to diverse biological systems.**