Targeting and assembly of E. coli division proteins

描述（由申请人提供）： 在细菌如大肠杆菌中，胞质分裂由两种必需且高度保守的细胞骨架蛋白：微管蛋白样FtsZ和肌动蛋白样FtsA协调。这些蛋白质在细胞分裂位点的内膜上共同组装成一个环形聚合结构，称为Z环。一旦组装好，这个环就会招募一个由其他蛋白质组成的大复合体到膜上，可能分布在单个的亚复合体中。这种蛋白质机器，通常被称为分裂体，诱导合成隔膜肽聚糖，同时在生长的隔膜的前缘收缩，最终将细胞一分为二。机器需要健壮，但对各种输入做出响应，因此过度建造。这项建议的重点是FtsA及其与FtsZ和后来的分裂体蛋白的相互作用，因为最近的研究结果表明，FtsA调节FtsZ的组装，除了其在束缚FtsZ聚合物的膜和招聘后来的分裂体组件的作用。我们假设FtsA介导的FtsZ聚合物的回收增加了分裂子复合物的膜附着位点的数量，从而稳定了机器并最大化其灵活性。我们建议（一）阐明如何结合ATP和ADP刺激FtsA的活动和FtsZ的相互作用;（二）定义FtsA和FtsZ亚基内FtsZ聚合物的分子之间的接触;和（iii）了解FtsZ/FtsA复合物如何与后来的divisome subcomplex相互作用。细菌细胞分裂的研究之所以重要，有两个原因。首先，这是一个需要理解的基本细胞过程。其次，随着目前新型抗生素的缺乏，细菌胞质分裂的普遍和基本过程越来越成为抗菌药物的靶点。 公共卫生相关性： 本项目研究细菌细胞分裂的分子机制。细胞分裂装置中高度保守的蛋白质代表了新疗法的新靶点。

DESCRIPTION (provided by applicant): In bacteria such as Escherichia coli, cytokinesis is orchestrated by two essential and highly conserved cytoskeletal proteins: tubulin-like FtsZ and actin-like FtsA. These proteins coassemble into a circumferential polymeric structure, called the Z ring, on the inner membrane at the site of cell division. Once assembled, the ring then recruits a large complex of other proteins to the membrane, probably distributed in individual subcomplexes. This protein machine, often called the divisome, induces synthesis of septal peptidoglycan while constricting at the leading edge of the growing septum, eventually splitting the cell into two. The machine needs to be robust, yet responsive to a variety of inputs, and is therefore overbuilt. This proposal focuses on FtsA and its interactions with FtsZ and with later divisome proteins, because recent results indicate that FtsA regulates assembly of FtsZ, in addition to its role in tethering FtsZ polymers to the membrane and recruiting later divisome components. We hypothesize that FtsA-mediated recycling of FtsZ polymers increases the number of membrane attachment sites for divisome subcomplexes, which stabilizes the machine and maximizes its flexibility. We propose to (i) elucidate how binding of ATP and ADP stimulates FtsA activity and its interaction with FtsZ; (ii) define the molecular contacts between FtsA and FtsZ subunits within FtsZ polymers; and (iii) understand how the FtsZ/FtsA complex interacts with the later divisome subcomplexes. The study of bacterial cell division is important for two reasons. First, it is a basic cellular process that needs to be understood. Second, with the current scarcity of novel antibiotics, the universal and essential process of bacterial cytokinesis is increasingly relevant as a target of antimicrobial drugs. PUBLIC HEALTH RELEVANCE: This project investigates the molecular mechanism of bacterial cell division. The highly conserved proteins in the cell division apparatus represent novel targets for new therapeutics.