The molecular control of bacterial programmed cell death

对金黄色葡萄球菌cid和lrg操纵子的研究为 深入了解细菌胞壁蛋白水解酶活性和自溶的调节控制， 导致了一个模型，其中该系统在功能上类似于 程序性细胞死亡（PCD）在更复杂的真核生物中。虽然希德和勒格 蛋白质已经显示分别与噬菌体holins和antiholins相似， 其对于在细胞裂解阶段期间控制细胞死亡和裂解是基本的。 噬菌体感染，其所利用的精确分子/生化机制， 在细胞死亡和裂解过程中的细菌对应物仍有待确定。在当前 建议，我们已经建立在我们实验室最近的研究表明，细胞质 酸化和丙酮酸代谢是细菌细胞死亡的关键方面， Cid和Lrg蛋白的特殊功能。在第一个具体目标中，我们将利用分子 用遗传学方法研究CidA/B蛋白与丙酮酸的关系 控制细菌细胞死亡的代谢酶。第二个目标是利用生物物理学 方法来测试模型，Cid和Lrg介导的运输是一个基本方面的 控制细菌细胞死亡。第三个也是最后一个目标将探索CidR介导的调节 该系统的重点是鉴定诱导其表达的效应分子。 活动总的来说，这些目标中描述的实验产生的结果将说明 细菌PCD的分子机制，并揭示代谢控制 其调节所需的元素，最终导致改善治疗策略，以对抗 细菌感染

Studies of the Staphylococcus aureus cid and lrg operons have provided important insight into the regulatory control of bacterial murein hydrolase activity and autolysis and have led to a model in which this system is functionally analogous to the control elements of programmed cell death (PCD) in more complex eukaryotic organisms. Although the Cid and Lrg proteins have been shown to be similar to bacteriophage holins and antiholins, respectively, which are fundamental to the control of cell death and lysis during the lytic stage of a bacteriophage infection, the precise molecular/biochemical mechanisms utilized by their bacterial counterparts during cell death and lysis remain to be determined. In the current proposal, we have built on recent studies in our laboratory demonstrating that cytoplasmic acidification and pyruvate metabolism are critical aspects of bacterial cell death to probe the specific functions of the Cid and Lrg proteins. In the first specific aim we will utilize a molecular genetic approach to examine the relationship between the CidA/B proteins and pyruvate metabolic enzymes in the control of bacterial cell death. The second aim will utilize a biophysical approach to test the model that Cid- and Lrg-mediated transport is a fundamental aspect of the control of bacterial cell death. The third and final aim will explore the CidR-mediated regulation of this system with a focus on the identification of the effector molecule(s) that induces its activity. Overall, the results generated by the experiments described in these aims will illuminate the molecular mechanisms underlying bacterial PCD and uncover the metabolic control elements required for its regulation, ultimately leading to improved therapeutic strategies to fight bacterial infections.