A Novel Phosphodiesterase of the GdpP Family Modulates Cyclic di-AMP Levels in Response to Cell Membrane Stress in Daptomycin-Resistant Enterococci
A Novel Phosphodiesterase of the GdpP Family Modulates Cyclic di-AMP Levels in Response to Cell Membrane Stress in Daptomycin-Resistant Enterococci
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DOI：
10.1128/aac.01422-16
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发表时间：
2017-01
影响因子：
4.9
通讯作者：
Xu Wang;M. Davlieva;Jinnethe Reyes;D. Panesso;C. Arias;Y. Shamoo
中科院分区：
文献类型：
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作者：
Xu Wang;M. Davlieva;Jinnethe Reyes;D. Panesso;C. Arias;Y. Shamoo
摘要 LiaFSR 膜应激途径中的替代通常与粪肠球菌和屎肠球菌中抗菌肽耐药性的出现有关。环二-AMP (c-di-AMP) 是一种重要的信号分子，影响细菌生理学的许多方面，包括应激反应。我们之前已经在粪肠球菌中发现了一个基因（称为 yybT）突变，该突变与达托霉素耐药性的发展相关，导致预测蛋白中 440 位（yybTI440S）发生变化。在这里，我们表明肠球菌中存在细胞内 c-di-AMP 信号传导，并且根据体外理化表征，我们表明 E. faecalisyybT 编码 GdpP 家族的环状二核苷酸磷酸二酯酶，该酶通过将 c-di-AMP 水解为 5'pApA 来表现出对 c-di-AMP 的特异性活性。粪肠球菌 GdpPI440S 取代使 c-di-AMP 磷酸二酯酶活性降低 11 倍以上，导致 c-di-AMP 水平进一步增加。此外，导致粪肠球菌和屎肠球菌对达托霉素过敏的liaR（编码LiaFSR系统的反应调节因子）的缺失也导致c-di-AMP水平升高，这表明LiaFSR应激反应途径的变化与更广泛的生理变化有关。综上所述，我们的数据表明，c-di-AMP 库的调节与抗生素诱导的细胞膜应激反应密切相关，通过 GdpP 活性或通过 LiaFSR 系统的信号传导的变化。
ABSTRACT Substitutions in the LiaFSR membrane stress pathway are frequently associated with the emergence of antimicrobial peptide resistance in both Enterococcus faecalis and Enterococcus faecium. Cyclic di-AMP (c-di-AMP) is an important signal molecule that affects many aspects of bacterial physiology, including stress responses. We have previously identified a mutation in a gene (designated yybT) in E. faecalis that was associated with the development of daptomycin resistance, resulting in a change at position 440 (yybTI440S) in the predicted protein. Here, we show that intracellular c-di-AMP signaling is present in enterococci, and on the basis of in vitro physicochemical characterization, we show that E. faecalisyybT encodes a cyclic dinucleotide phosphodiesterase of the GdpP family that exhibits specific activity toward c-di-AMP by hydrolyzing it to 5′pApA. The E. faecalis GdpPI440S substitution reduces c-di-AMP phosphodiesterase activity more than 11-fold, leading to further increases in c-di-AMP levels. Additionally, deletions of liaR (encoding the response regulator of the LiaFSR system) that lead to daptomycin hypersusceptibility in both E. faecalis and E. faecium also resulted in increased c-di-AMP levels, suggesting that changes in the LiaFSR stress response pathway are linked to broader physiological changes. Taken together, our data show that modulation of c-di-AMP pools is strongly associated with antibiotic-induced cell membrane stress responses via changes in GdpP activity or signaling through the LiaFSR system.