Bacterial cell envelope in polar positioning of autotransporter proteins

描述（由申请人提供）：自体转运蛋白是革兰氏阴性菌中最丰富的分泌蛋白家族。许多已被鉴定的是毒力蛋白。我们之前已经证明，自转运蛋白在细菌极点分泌，并且这些蛋白在穿过细胞质膜分泌之前，以细菌细胞质中的极点为目标。我们的初步数据表明，细胞分裂蛋白FtsQ参与建立由自转运体识别的极性位置信息，并且FtsQ的质周结构域足以产生这些信息。我们建议探索性研究细胞包膜重塑在细胞质中由自转运蛋白识别的极性位置信息的建立中的作用。我们的具体目标是：1。表征志贺氏菌自转运体IcsA极性建立缺陷的FtsQ突变体。2. 用一种无偏的方法鉴定并表征FtsQ下游通路中自转运体极性的蛋白质。3. 使用候选方法确定并表征在自转运体极性途径中与FtsQ相互作用的蛋白质。我们在此应用中提出的探索性研究将对原核生物极性建立的机制以及细胞包膜的动态发育和重塑产生深入的见解。

DESCRIPTION (provided by applicant): Autotransporters are the most abundant family of secreted proteins in gram-negative bacteria. Many of those that have been characterized are virulence proteins. We have previously shown that autotransporter proteins are secreted at the bacterial pole and that these proteins are targeted to the pole in the bacterial cytoplasm, prior t secretion across the cytoplasmic membrane. Our preliminary data indicate that the cell division protein FtsQ is involved in establishing polar positional information recognized by autotransporters and that the periplasmic domain of FtsQ is sufficient for the generation of this information. We propose exploratory investigations into the role of cell envelope remodeling in the establishment of polar positional information that is recognized in the cytoplasm by autotransporter proteins. Our specific aims are: 1. Characterize mutants of FtsQ defective in establishing polarity of the Shigella spp. autotransporter IcsA. 2. Identify using an unbiased approach, and characterize, proteins in the pathway downstream of FtsQ in autotransporter polarity. 3. Identify using a candidate approach, and characterize, proteins that interact with FtsQ in the autotransporter polarity pathway. The exploratory investigations we propose in this application will generate insights into the mechanisms involved in the establishment of polarity and into the dynamic development and remodeling of the cell envelope in prokaryotes.