Probing the Role of FtsQLB in Regulating Septal Cell Wall Synthesis Activity

项目摘要 细胞壁收缩，即新细胞壁的合成和旧细胞壁的分裂，是细胞壁收缩的附加过程。 细胞分裂过程中的一个步骤。细胞壁的合成和降解， 肽聚糖（PG）必须高度协调，因为错误调节可导致细胞的致命裂解。的 分裂体是一种由30多种蛋白质组成的大分子复合物，负责这一极其协调的过程。 FtsZ是一种微管蛋白同源物，也是一种必需的分裂体蛋白，它通过聚合 在中间细胞处形成环状结构（Z环）。该Z形环充当用于其它构件的支架（称为Z形轨道）。 分裂体蛋白，包括隔PG（sPG）合酶复合物、FtsWI和调节剂FtsN和FtsQLB。 分裂体蛋白质可以离开Z-轨道到第二轨道（sPG-轨道）上，其中发生sPG合成。这 本申请提出研究FtsQLB复合物在高血压患者中调节FtsWI活性的作用。 时空分辨率在E.杆菌Aim 1使用单分子跟踪（SMT）， 三维（3D）超分辨率成像以研究FtsQLB如何耦合到Z轨道。我会 研究FtsQLB如何响应改变的FtsZ动态。目的2关注sPG合成的调节 FtsWI的活动。使用相同的SMT和成像方法，我将确定FtsQLB是否与FtsWI相结合 在sPG赛道上。最后，目标3使用超裂变和显性负突变体来剖析关键的作用， FtsQLB、FtsN和FtsWI的蛋白-蛋白相互作用。利用单分子活细胞成像结合 微扰分析将使我能够确定负责细胞壁的分子决定因素 收缩，提供洞察细菌细胞分裂的空间和时间调节。由于高度 细菌细胞壁的保守性质，从这项研究中学到的机制见解可以适用于 广泛的细菌种类，以促进抗微生物药物的开发。

Project Summary Cell wall constriction, the synthesis of new cell wall and the splitting of the old cell wall, is an additional step during cell division that occurs in walled bacteria. The synthesis and degradation of the cell wall, made of peptidoglycan (PG), must be highly coordinated because mis-regulation can result in fatal lysis of the cell. The divisome, a macromolecular complex of over 30 proteins, is responsible for this extremely coordinated process. FtsZ, a tubulin homolog and GTPase, is an essential divisome protein that begins cell division by polymerizing into a ring-like structure (Z-ring) at the midcell. This Z-ring acts as a scaffold (known as the Z-track) for other divisome proteins including the septal PG (sPG) synthase complex, FtsWI, and regulators FtsN and FtsQLB. Divisome proteins can exit the Z-track onto a second track (sPG-track) where sPG synthesis occurs. This application proposes to study the role of the FtsQLB complex in regulating the activity of FtsWI in with high spatiotemporal resolution during cell wall constriction in E. coli. Aim 1 uses single molecule tracking (SMT) and three-dimensional (3D) superresolution imaging to investigate how FtsQLB is coupled to the Z-track. I will examine how FtsQLB responds to altered FtsZ dynamics. Aim 2 focuses on the modulation of the sPG synthesis activity of FtsWI. Using the same SMT and imaging approaches I will determine if FtsQLB is coupled with FtsWI on the sPG track. Finally, Aim 3 uses superfission and dominant negative mutants to dissect the roles of key protein-protein interactions of FtsQLB, FtsN, and FtsWI. The use of single-molecule live cell imaging combined with perturbational analysis will enable me to identify molecular determinants responsible for cell wall constriction, providing insight into the spatial and temporal regulation of bacterial cell division. Due to the highly conserved nature of the bacterial cell wall, mechanistic insights learned from this study can be applicable to a wide range of bacterial species to facilitate the development of antimicrobial drugs.