Modulation of CrbS-Dependent Activation of the Acetate Switch in Vibrio cholerae
Modulation of CrbS-Dependent Activation of the Acetate Switch in Vibrio cholerae
复制标题
DOI：
10.1128/jb.00380-18
复制
发表时间：
2018-12-01
影响因子：
3.2
通讯作者：
Purdy, Alexandra E.
中科院分区：
文献类型：
--
作者：
Muzhingi, Itai;Prado, Cecilia;Purdy, Alexandra E.
霍乱弧菌通过 CrbS/R 双组分系统的活性控制与节肢动物宿主相互作用的致病性。该信号通路调节乙酸盐的消耗，进而改变与节肢动物（包括果蝇）相互作用的相对毒力。 CrbS 是一种组氨酸激酶，通过假定的 STAC 和 PAS 结构域将转运蛋白样结构域与其信号传导装置连接起来。 CrbS 及其同源反应调节因子是乙酰辅酶 A (乙酰辅酶 A) 合成酶（acs 的产物）表达所必需的，该酶将乙酸盐转化为乙酰辅酶 A。我们证明 CrbS 的 STAC 结构域是培养物中信号传导所必需的；如果没有它，acs 转录在 LB 培养基中会减少，并且霍乱弧菌不能在醋酸盐基本培养基上生长。然而，该菌株对果蝇仍然具有毒力，并且在感染期间表达与野生型相似的 acs。这表明果蝇胃肠道中存在调节 CrbS 的独特信号或环境变量。其次，我们提供了支持 CrbR 的证据，CrbR 是与 CrbS 相互作用的反应调节因子，直接与 acs 启动子结合，并且我们确定了 CrbR 可能靶向的启动子区域。我们进一步证明营养信号与 cAMP 受体蛋白 (CRP)-cAMP 系统一起控制 acs 转录，但调节可能间接发生，因为 CRP-cAMP 激活 crbS 和 crbR 基因的表达。最后，我们定义了 Pta-AckA 系统在霍乱弧菌中的作用，并确定了该病原体中乙酸盐排泄途径中内置的冗余。 重要性 CrbS 是传感器组氨酸激酶的独特家族的成员，因为其结构表明它可能将信号传导与分子的运输联系起来。然而，CrbS 感知和传达外界信息的机制尚不清楚。在弧菌科中，CrbS 的直系同源物调节乙酸代谢，进而影响与宿主生物体的相互作用。在这里，我们将 CrbS 置于更大的监管框架内，证明 crbS 受到营养传感系统的调控。此外，CrbS 结构域可能在感染和培养生长过程中的信号传导中发挥多种作用，表明宿主识别的独特机制。最后，我们定义了其他途径在乙酸盐通量中的作用，作为进一步研究该代谢连接点的基础。
Vibrio cholerae controls the pathogenicity of interactions with arthropod hosts via the activity of the CrbS/R two-component system. This signaling pathway regulates the consumption of acetate, which in turn alters the relative virulence of interactions with arthropods, including Drosophila inelanogaster. CrbS is a histidine kinase that links a transporter-like domain to its signaling apparatus via putative STAC and PAS domains. CrbS and its cognate response regulator are required for the expression of acetyl coenzyme A (acetyl-CoA) synthetase (product of acs), which converts acetate to acetyl-CoA. We demonstrate that the STAC domain of CrbS is required for signaling in culture; without it, acs transcription is reduced in LB medium, and V. cholerae cannot grow on acetate minimal media. However, the strain remains virulent toward Drosophila and expresses acs similarly to the wild type during infection. This suggests that there is a unique signal or environmental variable that modulates CrbS in the gastrointestinal tract of Drosophila. Second, we present evidence in support of CrbR, the response regulator that interacts with CrbS, binding directly to the acs promoter, and we identify a region of the promoter that CrbR may target. We further demonstrate that nutrient signals, together with the cAMP receptor protein (CRP)-cAMP system, control acs transcription, but regulation may occur indirectly, as CRP-cAMP activates the expression of the crbS and crbR genes. Finally, we define the role of the Pta-AckA system in V. cholerae and identify redundancy built into acetate excretion pathways in this pathogen.IMPORTANCE CrbS is a member of a unique family of sensor histidine kinases, as its structure suggests that it may link signaling to the transport of a molecule. However, mechanisms through which CrbS senses and communicates information about the outside world are unknown. In the Vibrionaceae, orthologs of CrbS regulate acetate metabolism, which can, in turn, affect interactions with host organisms. Here, we situate CrbS within a larger regulatory framework, demonstrating that crbS is regulated by nutrient-sensing systems. Furthermore, CrbS domains may play various roles in signaling during infection and growth in culture, suggesting a unique mechanism of host recognition. Finally, we define the roles of additional pathways in acetate flux, as a foundation for further studies of this metabolic nexus point.