Signal transduction by the essential signalling molecule cyclic di-AMP in Bacillus subtilis

枯草芽孢杆菌中必需信号分子环二腺苷的信号转导

• 批准号: 314789836
• 负责人: Professor Dr. Jörg Stülke
• 金额: --
• 依托单位: Abteilung für Allgemeine Mikrobiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/314789836?language=en
• 关键词: Signal; transduction; essential; signalling; molecule

Bacteria use second messengers for signal transduction in order to achieve rapid adaptation to changing environmental conditions. Cyclic nucleotides and dinucleotides are among the most common second messengers. The Gram-positive soil bacterium Bacillus subtilis forms c-di-GMP and c-di-AMP. For both second messengers, multiple synthesizing enzymes are present in B. subtilis. While c-di-GMP is involved in the control of motility, c-di-AMP seems to play a role in several signal transduction processes. So far, functions in the control of cell wall homeostasis and cell division as well as in the regulation of potassium uptake have been described. We have studied the activities of the diadenylate cyclases CdaA and CdaS, that have not been studied before. We observed that c-di-AMP is essential for the growth of B. subtilis, but that accumulation of the second messenger does also compromise the growth of the cells. In order to get molecular insights into the signal transduction processes we have identified the PII-like signal transduction protein DarA as a c-di-AMP binding protein. With this proposal we want to study the control of c-di-AMP synthesis in B. subtilis, in particular by the diadenylate cyclase CdaA, which seems to be causative for the essential function of c-di-AMP. In this context, we will study the molecular details of the interaction between CdaA, its modulator protein CdaR, and the essential phosphoglucosamine mutase GlmM. These three proteins are all encoded in a conserved operon in Gram-positive bacteria with low GC content. In the second step, we wish to unravel the function of DarA. For this purpose, we will co-purify DarA with its interaction partners, and identify them by mass spectrometry. It is well established that PII proteins can interact with a variety of other proteins to control their activity, and we think this may also be the case for DarA. Finally, the major question of this project will be the elucidation of the reason for the essentiality of c-di-AMP. Based on our previous results, we think that c-di-AMP is required for the activity of an essential protein of cell wall biosynthesis. We have developed experimental strategies to identify this protein. We are confident that this experimental program at the interface of molecular genetics and proteomics will provide major novel insights into the function of this unique essential second messenger.

细菌利用第二信使进行信号转导，以实现对不断变化的环境条件的快速适应。环核苷酸和二核苷酸是最常见的第二信使。革兰氏阳性土壤细菌枯草芽孢杆菌形成c-di-GMP和c-diAMP。对于这两个第二信使，枯草杆菌中都存在多种合成酶。虽然c-di-GMP参与运动控制，但c-di-AMP似乎在几个信号转导过程中发挥作用。到目前为止，已经描述了在控制细胞壁动态平衡和细胞分裂以及调节钾吸收方面的功能。我们研究了双腺苷环化酶CDAA和CDA的活性，这是以前没有研究过的。我们观察到c-di-AMP对于枯草杆菌的生长是必不可少的，但第二信使的积累也损害了细胞的生长。为了从分子水平深入了解信号转导过程，我们将类PII信号转导蛋白DARA鉴定为c-di-AMP结合蛋白。根据这一建议，我们想要研究c-diAMP在枯草杆菌中合成的控制，特别是通过二腺苷环化酶CDAA，它似乎是c-diAMP的基本功能的起因。在此背景下，我们将研究CDAA、其调节蛋白CdaR和必需的磷酸氨基葡萄糖变位酶GlmM之间相互作用的分子细节。在低GC含量的革兰氏阳性细菌中，这三种蛋白质都编码在一个保守的操纵子中。在第二步中，我们希望解开Dara的功能。为此，我们将与DARA的相互作用伙伴共同纯化DARA，并通过质谱学对其进行鉴定。众所周知，PII蛋白可以与各种其他蛋白相互作用来控制其活性，我们认为DARA也可能是这样。最后，本项目的主要问题将是阐明c-di-AMP的重要性的原因。根据我们以前的研究结果，我们认为c-di-AMP是细胞壁生物合成所必需的蛋白质活性所必需的。我们已经开发了实验策略来识别这种蛋白质。我们相信，这一分子遗传学和蛋白质组学交界处的实验计划将为这一独特的重要第二信使的功能提供重大的新见解。