Department of Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, Michigan, USA.
J Bacteriol. 2019 Jun 21;201(14). doi: 10.1128/JB.00761-18. Print 2019 Jul 15.
The phage shock protein (Psp) system is a stress response pathway that senses and responds to inner membrane damage. The genetic components of the Psp system are present in several clinically relevant Gram-negative bacteria, including However, most of the current knowledge about the Psp response stems from studies in and In fact, the Psp response in has remained completely uncharacterized. In this study, we demonstrate that does have a functional Psp response system. We found that overexpression of GspD (EpsD), the type II secretion system secretin, induces the Psp response, whereas other secretins do not. In addition, we have identified several environmental conditions that induce this stress response. Our studies on the genetic regulation and induction of the Psp system in suggest that the key regulatory elements are conserved with those of other Gram-negative bacteria. While a null strain is fully capable of colonizing the infant mouse intestine, it exhibits a colonization defect in a zebrafish model, indicating that this response may be important for disease transmission in the environment. Overall, these studies provide an initial understanding of a stress response pathway that has not been previously investigated in leads a dual life cycle, as it can exist in the aquatic environment and colonize the human small intestine. In both life cycles, encounters a variety of stressful conditions, including fluctuating pH and temperature and exposure to other agents that may negatively affect cell envelope homeostasis. The phage shock protein (Psp) response is required to sense and respond to such insults in other bacteria but has remained unstudied in Interestingly, the Psp system has protein homologs, principally, PspA, in a number of bacterial clades as well as in archaea and plants. Therefore, our findings not only fill a gap in knowledge about an unstudied extracytoplasmic stress response in , but also may have far-reaching implications.
噬菌体休克蛋白 (Psp) 系统是一种感应和响应内膜损伤的应激反应途径。该系统的遗传成分存在于几种临床相关的革兰氏阴性菌中，包括 然而，目前关于 Psp 反应的大部分知识都源于 在 和 的研究。事实上， 中的 Psp 反应仍然完全没有被描述过。在这项研究中，我们证明 确实具有功能性的 Psp 反应系统。我们发现，GspD (EpsD) 的过表达，即 II 型分泌系统的分泌素，会诱导 Psp 反应，而其他 分泌素则不会。此外，我们还确定了几种诱导这种应激反应的环境条件。我们对 中 Psp 系统的遗传调控和诱导的研究表明，关键调控元件与其他革兰氏阴性菌的调控元件保守。虽然 缺失株完全能够定植幼鼠肠道，但在斑马鱼模型中表现出定植缺陷，表明该反应可能对环境中的疾病传播很重要。总的来说，这些研究为以前未在 中研究过的应激反应途径提供了初步的理解。 过着双重的生活周期，因为它可以存在于水生环境中并定植于人类小肠。在这两种生命周期中， 都会遇到各种应激条件，包括 pH 值和温度的波动以及暴露于其他可能对细胞包膜内稳态产生负面影响的物质。噬菌体休克蛋白 (Psp) 反应是感应和响应其他细菌中这些攻击所必需的，但在 中尚未进行研究。有趣的是，Psp 系统在许多细菌类群以及古菌和植物中都有蛋白质同源物，主要是 PspA。因此，我们的发现不仅填补了对一个未被研究的细胞外应激反应的知识空白，而且可能具有深远的意义。
