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Key Molecular Mechanisms of c-di-GMP Signaling in Bacterial Biofilm Formation

细菌生物膜形成中 c-di-GMP 信号传导的关键分子机制

基本信息

批准号：
269737138
负责人：
Professorin Dr. Regine Hengge
金额：
--
依托单位：
Arbeitsgruppe Mikrobiologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/269737138?language=en
关键词：
Key Molecular Mechanisms di GMP

项目摘要

Bacterial biofilms colonize diverse surfaces and are highly resistant against antibiotics or the immune system. In these biofilms, cells are embedded in a self-produced matrix consisting of secreted proteins, amyloid fibres (e.g. curli), exopolysaccharides (e.g. cellulose) and even DNA. These matrix components determine the complex microarchitecture and morphology of these biofilms. In E. coli, synthesis of curli fibres and cellulose is under control of the stationary phase sigma factor RpoS and the second messenger c-di-GMP. The latter is produced by diguanylate cyclases (DGC, with GGDEF domains) and is degraded by specific phosphodiesterases (PDE, with EAL domains). Many of these differentially expressed DGCs and PDEs are membrane-associated and activity-controlled via N-terminal sensory domains. Many bacteria possess multiple GGDEF/EAL domain proteins (29 in E. coli K-12), which has led to the concept of locally acting c-di-GMP control modules based on direct and highly specific protein-protein interactions. Our recent analysis of YciR, the first and paradigmatic trigger enzyme in bacterial second messenger signaling and a key switching device for the production of curli and cellulose, has demonstrated how this can work: YciR is at the same time (i) a regulator that inhibits two target proteins by direct interaction, (ii) a PDE, and (iii) a c-di-GMP effector component, because its binding and degradation of c-di-GMP releases its direct interaction with the target proteins (a DGC and a transcription factor required to produce curli and cellulose).The project proposed here will focus on the molecular mechanisms that underly two key aspects of c-di-GMP signaling:1. Local c-di-GMP signaling that involves specific protein-protein interactions of c-di-GMP-related trigger enzymes: here, the potential role of YciR acting also in conjunction with three additional DGCs, as well as the molecular functions of two additional PDEs and putative trigger enzymes that are involved in cellulose biosynthesis and direct regulation of gene expression, respectively, will be characterized.2. Sensory input into c-di-GMP signaling: here, the goal will be to identify novel environmental input signals into biofilm formation and to assign specific signal perception to distinct DGCs and PDEs. The molecular mechanisms of signal processing by specific N-terminal sensory domains of DGCs and PDEs will be characterized with a particular focus on redox-responsive PDEs and multiple signal integration by multi-domain DGCs and PDEs.Finally, the integration of these molecular mechanisms within the large regulatory networks that generate functionality of a biofilm will be elucidated. Since c-di-GMP signaling is almost ubiquitously used by bacteria to control biofilm formation, insights generated by this project will open new perspectives on anti-biofilm strategies and drugs.

细菌生物膜定植于不同的表面，并且对抗生素或免疫系统具有高度抗性。在这些生物膜中，细胞嵌入由分泌蛋白质、淀粉样纤维（例如卷曲）、胞外多糖（例如纤维素）甚至DNA组成的自产基质中。这些基质成分决定了这些生物膜的复杂微结构和形态。在大肠在大肠杆菌中，卷曲纤维和纤维素的合成受固定相σ因子RpoS和第二信使c-di-GMP的控制。后者由二鸟苷酸环化酶（DGC，具有GGDEF结构域）产生，并由特异性磷酸二酯酶（PDE，具有EAL结构域）降解。这些差异表达的DGC和PDE中的许多是膜相关的，并且通过N-末端感觉结构域进行活性控制。许多细菌具有多个GGDEF/EAL结构域蛋白（E. coli K-12），这导致了基于直接且高度特异性的蛋白质-蛋白质相互作用的局部作用c-di-GMP控制模块的概念。我们最近对YciR的分析，细菌第二信使信号传导中的第一个和范例触发酶，以及产生卷曲和纤维素的关键开关装置，已经证明了这是如何工作的：YciR同时是（i）通过直接相互作用抑制两种靶蛋白的调节剂，（ii）PDE，和（iii）c-di-GMP效应物组分，因为c-di-GMP的结合和降解释放了其与靶蛋白（产生卷曲和纤维素所需的DGC和转录因子）的直接相互作用。涉及c-di-GMP相关触发酶的特异性蛋白质-蛋白质相互作用的局部c-di-GMP信号传导：在此，将表征还与三种另外的DGC结合起作用的YciR的潜在作用，以及分别涉及纤维素生物合成和基因表达的直接调节的两种另外的PDE和推定的触发酶的分子功能。c-di-GMP信号传导的感觉输入：在这里，目标是识别生物膜形成的新环境输入信号，并将特定的信号感知分配给不同的DGC和PDE。通过特定的N-末端感觉域的DGCs和PDEs的信号处理的分子机制将其特征在于与氧化还原响应PDEs和多域DGCs和PDEs的多个信号整合的特别关注。最后，这些分子机制的整合内的大型监管网络，产生生物膜的功能将得到阐明。由于c-di-GMP信号几乎被细菌普遍用于控制生物膜形成，因此该项目产生的见解将为抗生物膜策略和药物开辟新的视角。