Forespore Engulfment During B subtilis Sporulation

枯草芽孢杆菌孢子形成过程中前孢子的吞噬

• 批准号: 7486444
• 负责人: Kit J Pogliano
• 金额: $ 2.32万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7486444
• 关键词: Affect; Anthrax disease; Antibiotics; Bacillus (bacterium); Bacillus subtilis; Bacteria; Bacterial Proteins; Biochemical Genetics; Biological; Biological Process; Botulism; Cell Separation; Cell Wall; Cell division; Cells; Cellular Structures; Chimeric Proteins; Chromosome Segregation; Chromosomes; Clostridium; Complex; Cytolysis; Cytoplasm; Diffusion; Drug Delivery Systems; Endospore-Forming Bacteria; Ensure; Enzymes; Event; Genetic; Goals; Green Fluorescent Proteins; Helix (Snails); Hydrolysis; Immobilization; In Vitro; Infectious Agent; Investigation; Life; Lipid Bilayers; Localized; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Methods; Modeling; Mothers; N-Acetylmuramoyl-L-alanine Amidase; Object Attachment; Pathway interactions; Peptidoglycan; Phagocytosis; Photobleaching; Process; Proteins; Regulation; Reproduction spores; Research; Research Personnel; Site-Directed Mutagenesis; Specificity; Staging; System; Testing; ear helix; in vivo; intracellular protein transport; macromolecule; migration; mutant; novel; programs; protein localization location; protein protein interaction; tool

Bacteria from the genera Bacillus and Clostridium produce unusually durable and long lived spores that are the infectious agent of Anthrax and Botulism, and which are assembled in the cytoplasm of another cell. This unique cell within a cell structure (the endospore) is produced by a phagocytosis-like process known as engulfment. During engulfment, the membrane of the larger mother cell migrates around the smaller forespore, until it is completely enclosed within the mother cell cytoplasm. Engulfment provides a dramatic example of the dynamic capabilities of the bacterial cell, but its mechanism remains unclear. We have developed new tools for the study of engulfment, membrane fusion and protein localization and identified mutants defective in these steps. The fusion defective mutant is defective in both the final step of engulfment and cell division, and affects a conserved protein also involved in the final stages of chromosome segregation. We suggest that these proteins coordinate chromosome segregation with the completion of cell division, to ensure that cell separation does not damage an incompletely segregated chromosome. We have also identified two mechanisms by which the membranes move around the forespore, one of which depends on the SpollD peptidoglycan hydrolase. We will take a combined cell biological, genetic and biochemical approach to study the spatial regulation of peptidoglycan hydrolysis, the protein-protein interactions that mediate engulfment, as well as to understand the mechanisms by which bacterial cells catalyze membrane fusion and are dynamically organized. Engulfment provides a dispensable system to study cell biological events that are essential for all bacteria, such as protein localization and membrane fusion. It also requires peptidoglycan hydrolases, which are found in all bacteria that synthesize peptidoglycan, and which are potentially lethal because their activity can result in cell lysis without strict spatial and temporal regulation. Indeed, the lethality of many commercial antibiotics requires these hydrolytic enzymes. Engulfment provides an ideal system for understanding how bacteria control these potentially lethal enzymes, which are attractive targets for novel antibiotics, and has the potential to identify new drug targets in proteins that remodel bacterial membranes or mediate localization of bacterial proteins.

芽孢杆菌属和梭菌属的细菌产生异常耐用且寿命长的孢子， 炭疽和肉毒中毒的传染剂，并在另一个细胞的细胞质中组装。 细胞结构内的这种独特细胞（内生孢子）是通过类似吞噬作用的过程产生的，称为 吞没。在吞噬过程中，较大母细胞的膜迁移到较小的母细胞周围 前孢子，直到它完全封闭在母细胞的细胞质内。吞噬提供了戏剧性的 细菌细胞动态能力的例子，但其机制仍不清楚。我们有 开发了用于研究吞噬、膜融合和蛋白质定位的新工具并鉴定 这些步骤中存在缺陷的突变体。融合缺陷突变体在吞噬的最后一步都有缺陷 和细胞分裂，并影响也参与染色体最后阶段的保守蛋白 隔离。我们认为这些蛋白质协调染色体分离与细胞的完成 分裂，以确保细胞分离不会损坏不完全分离的染色体。我们有 还确定了膜在前孢子周围移动的两种机制，其中之一取决于 SpollD 肽聚糖水解酶。我们将结合细胞生物学、遗传和生化 研究肽聚糖水解空间调控的方法，蛋白质-蛋白质相互作用 介导吞噬，以及了解细菌细胞催化膜的机制 融合并动态组织。吞噬为研究细胞生物学提供了一个可有可无的系统 对所有细菌都至关重要的事件，例如蛋白质定位和膜融合。它还需要 肽聚糖水解酶，存在于所有合成肽聚糖的细菌中， 可能致命，因为它们的活性可能导致细胞裂解，而无需严格的空间和时间调节。 事实上，许多商业抗生素的致死性需要这些水解酶。吞没提供 这是一个了解细菌如何控制这些潜在致命酶的理想系统，这很有吸引力 新型抗生素的靶点，并有潜力识别重塑蛋白质的新药物靶点 细菌膜或介导细菌蛋白质的定位。