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

基本信息

批准号：
7671904
负责人：
Kit J Pogliano
金额：
$ 3.15万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
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/7671904
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 Protein Dynamics 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

项目摘要

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.

来自芽孢杆菌和梭状芽胞杆菌的细菌会产生异常耐用的孢子炭疽和肉毒杆菌的感染剂，并在另一个细胞的细胞质中组装。细胞结构中的这种独特的细胞（内孢子）是由一种被称为吞噬作用的过程称为吞噬。在吞噬期间，较大的母细胞的膜在较小的前孔，直到将其完全封闭在母细胞细胞质中。吞噬提供了戏剧性的细菌细胞动态能力的示例，但其机制尚不清楚。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，并确定了在这些步骤中有缺陷的突变体。融合有缺陷的突变体在吞噬的最后一步中都是有缺陷的和细胞分裂，并影响染色体的最后阶段的保守蛋白隔离。我们建议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害未完全隔离的染色体。我们有还确定了膜在前孔周围移动的两种机制，其中一种取决于在Spolld肽聚糖水解酶上。我们将进行组合的细胞生物学，遗传和生化研究肽聚糖水解的空间调节方法，即蛋白质蛋白相互作用介导吞噬，并了解细菌细胞催化膜的机制融合并动态组织。吞噬提供了一个可分配的系统来研究细胞生物学对于所有细菌所必需的事件，例如蛋白质定位和膜融合。这也需要肽聚糖水解酶，在所有合成肽聚糖的细菌中都发现，它们是潜在的致命，因为它们的活性会导致细胞裂解而无需严格的空间和时间调节。实际上，许多商业抗生素的致死性需要这些水解酶。吞噬提供了解细菌如何控制这些潜在致命酶的理想系统，这些酶很有吸引力新型抗生素的靶标，并且有可能鉴定重塑蛋白质中的新药物靶标细菌膜或介导细菌蛋白的定位。