Acetylation of virulence factor regulatory proteins in V. cholerae

摘要 病原微生物的新陈代谢必须是灵活的，并有效地复制 寄主中的病原菌依赖于主动适应过程。霍乱弧菌暴露于 人类宿主内的各种环境，最终必须适应其可用营养物质 首选感染部位为小肠。小肠是胃肠道的一部分。 大多数食物的消化和吸收都发生了，从而为细菌提供了各种营养。 随着霍乱弧菌开始引起大量腹泻，这是该病的标志，细菌必须 再次适应营养可获得性的变化，以继续感染过程。因此，它可以是 预计霍乱弧菌在感染过程中的代谢状态会发生很大变化， 新陈代谢的变化与毒力基因的表达相协调。尽管新陈代谢之间的联系 状态和毒力因子的表达在几种病原体中都有很好的描述，但还没有 对霍乱弧菌进行了详细的调查。我们的初步结果表明，某些碳的不同有效性 与体内条件相关的来源会影响霍乱弧菌的毒力基因表达。此外， 我们发现，膜呼吸和中枢代谢基因的突变，如酶 参与TCA循环，影响霍乱弧菌毒力因子的表达。根据我们的观察， 在PTA-ACK途径中定义的突变体我们得出结论，乙酰辅酶A(AcCoA)，而不是乙酰磷酸， 在这一信号转导中起着重要作用。我们假设新陈代谢和毒力基因之间的这种联系 霍乱弧菌的调控是通过翻译后蛋白修饰，特别是通过 关键的毒力调节蛋白。重要的是，最近一项对霍乱弧菌全球乙酰组的研究揭示了 几种重要的毒力调节蛋白，包括TCPP、AphB和Phob的赖氨酸乙酰化。通过 将现代质谱分析与遗传和生化分析相结合，我们希望能更好地 了解acCoA影响毒力因子转录的机制。我们还将研究 霍乱弧菌乙酰转移酶基因在毒力因子修饰和确定中的作用 额外的整体蛋白质乙酰化模式(乙酰体)。因此，我们的研究有可能首次 时间，展示了赖氨酸乙酰化在霍乱弧菌毒力因子调节中的作用，并将进一步建立 中枢代谢在这种有机体发病机制中的重要性。总体而言，我们希望获得洞察力 这种有机体本身的代谢途径及其与作为寄主的一个重要方面的毒力的关系- 病原体相互作用。最终，这些信息可能会导致旨在 调节中枢代谢物和毒力因子表达的相互作用，不仅对霍乱弧菌，而且对霍乱弧菌 可能是其他病原体。

Abstract The metabolism of pathogenic microorganisms has to be flexible and the efficient replication of pathogenic bacteria in the host depends on an active adaptation process. Vibrio cholerae is exposed to a variety of environments within the human host and eventually has to adapt to the nutrients available at its preferred infection site, the small intestine. The small intestine is the part of the gastrointestinal tract where the majority of digestion and absorption of food takes place, thus providing a variety of nutrients for the bacteria. As V. cholerae start to cause the profuse diarrhea that is the hallmark of the disease, the bacteria have to once again adapt to the resulting changes in nutrient availability to continue the infection process. It can therefore be expected that the metabolic status in V. cholerae changes substantially during the course of infection and that changes in metabolism are coordinated with virulence gene expression. Although a link between the metabolic status and virulence factor expression has been well described in several pathogens, it has not been investigated in detail in V. cholerae. Our preliminary results suggest that different availability of certain carbon sources that have relevance to in vivo conditions affect virulence gene expression in V. cholerae. Moreover, we found that mutations in membrane respiration as well as central metabolism genes, such as enzymes involved in the TCA cycle, affect virulence factor expression in V. cholerae. Based on our observations with defined mutants in the PTA-ACK pathway we concluded that acetyl-CoA (acCoA), but not acetyl-phosphate, plays a role in this signal transduction. We hypothesize that this link between metabolism and virulence gene regulation in V. cholerae occurs via post-translational protein modification, specifically by lysine acetylation of key virulence regulatory proteins. Importantly, a recent study of the global acetylome of V. cholerae revealed lysine acetylation of several important virulence regulatory proteins, including TcpP, AphB, and PhoB. By combining modern mass spectrometry analyses with genetic and biochemical analyses we expect to better understand the mechanism by which acCoA affects virulence factor transcription. We will also examine the roles of putative V. cholerae acetyltransferase genes in virulence factor modification as well as determine additional overall protein acetylation patters (acetylomes). Thus, our study has the potential to, for the first time, demonstrate a role of lysine acetylation in V. cholerae virulence factor regulation and will further establish the importance of central metabolism in the pathogenesis of this organism. Overall, we expect to gain insights into the metabolic pathways of this organism per se and its relation to virulence as an important aspect of host- pathogen interaction. Ultimately, this information could lead to novel intervention strategies aimed at modulating the interplay of central metabolites and virulence factor expression, not only for V. cholerae but potentially other pathogens.