Global regulators converge to orchestrate metabolism, biofilm, and pathogenesis

项目摘要 腹泻病是资源贫乏地区发病率和死亡率的主要原因。为了殖民 肠道和引起疾病，成功的细菌病原体必须感知和响应肠道信号， 改变代谢和毒力因子表达。我们假设，通过理解关键的 肠道信号和它们激活的细菌调节网络，我们可以设计简单的饮食改变， 预防或减轻发病率和死亡率。 我们重点关注霍乱弧菌，严重的霍乱病的代理人。因为新陈代谢 我们研究的途径是高度保守的，这些发现也可以作为其他细菌的范例， 腹泻这项工作的目标是阐明复杂和高度保守的调控网络， 当霍乱弧菌进入肠道环境时被激活。 在这项资助的第一个4年资助期内，我们探索了全球新陈代谢调节器的作用， 称为葡萄糖特异性酶IIA的毒力。我们发现这个调节器是膜相关的 通过N-末端两亲性螺旋，并且膜缔合对于其与 它所调控的膜蛋白伴侣。基于这项工作，我们假设， 细菌细胞的膜可以充当调节蛋白的平台，所述调节蛋白感测并响应于细菌细胞的膜。 肠道环境中的营养信号。 在之前的资助期间，我们发现，全球转录的亚细胞位置 这种因子，即cAMP受体蛋白（CRP），是受环境条件调节的。在当前 在资助期间，我们建议通过研究CRP亚细胞调节来跟踪这些观察结果， 定位，亚细胞定位改变CRP基因转录激活的机制，以及 CRP亚细胞定位对霍乱弧菌毒力的功能意义。我们假设如果 CRP的亚细胞定位可以通过宿主饮食控制， 从而降低了霍乱引起的发病率和死亡率。

Project Summary Diarrheal disease is a leading cause of morbidity and mortality in resource-poor areas. In order to colonize the intestine and cause disease, successful bacterial pathogens must sense and respond to intestinal signals by altering both metabolism and virulence factor expression. We hypothesize that by understanding the critical intestinal signals and the bacterial regulatory networks they activate, we can devise simple dietary alterations that prevent or mitigate morbidity and mortality. We focus on Vibrio cholerae, the agent of the severe diarrheal disease cholera. Because the metabolic pathways we study are highly conserved, these findings also serve as a paradigm for other bacteria that cause diarrhea. The goal of this work is to elucidate the complex and highly conserved regulatory network that is activated when V. cholerae enters the intestinal environment. In the first 4-year funding period of this grant, we explored the role of a global regulator of metabolism and virulence known as glucose-specific Enzyme llA. We showed that this regulator is membrane-associated through an N-terminal amphipathic helix and that membrane association is critical for its interaction with integral membrane protein partners that it regulates. Based on this work, we hypothesize that the inner membrane of the bacterial cell may act as a platform for regulatory proteins that sense and respond to nutritional signals in the intestinal environment. During the previous funding period, we discovered that the subcellular location of the global transcription factor, the cAMP receptor protein (CRP), is regulated in response to environmental conditions. In the current funding period, we propose to follow up on these observations by investigating regulation of CRP subcellular localization, the mechanism by which subcellular localization alters CRP activation of gene transcription, and the functional significance of CRP subcellular localization for V. cholerae virulence. We hypothesize that if the subcellular localization of CRP can be controlled via host diet, it may be possible to reduce pathogen virulence and thereby the morbidity and mortality caused by cholera.