Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli
Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli
复制标题
尾锚定内膜蛋白 ElaB 提高应激抵抗力，同时减少大肠杆菌的持久性
DOI：
10.1128/jb.00057-17
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发表时间：
2017-05-01
影响因子：
3.2
通讯作者：
Wang, Xiaoxue
中科院分区：
文献类型：
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作者：
Guo, Yunxue;Liu, Xiaoxiao;Wang, Xiaoxue
摘要 宿主相关细菌，例如大肠杆菌，经常遇到各种与宿主相关的应激，例如营养缺乏、氧化应激和温度变化。人们对寻找介导应激反应的小内源蛋白越来越感兴趣。在这里，我们对大肠杆菌中的小 C 尾锚定内膜蛋白 ElaB 进行了表征。 ElaB 属于一类尾部锚定的内膜蛋白，具有 C 端跨膜结构域，但缺乏用于膜靶向的 N 端信号序列。该家族的蛋白质已被证明发挥着至关重要的作用，例如在真核生物中的膜运输和细胞凋亡中；然而，它们在原核生物中的作用很大程度上尚未被探索。在这里，我们发现 elaB 的转录在大肠杆菌的稳定期被诱导，稳定期 sigma 因子 RpoS 通过与 elaB 的启动子结合来调节 elaB 的转录。此外，ElaB 还可以保护细胞免受氧化应激和热休克应激的影响。然而，与膜肽毒素 TisB 和 GhoT 不同，ElaB 不会导致细胞死亡，并且 elaB 的缺失大大增加了持久细胞的形成。因此，我们证明破坏 C 尾锚定的内膜蛋白可以降低应激抵抗力；它还可能导致有害影响，例如大肠杆菌的持久性增加。重要性 大肠杆菌合成了数十种人们知之甚少的小膜蛋白，其中含有预测的跨膜结构域。在本研究中，我们表征了大肠杆菌中 C 尾锚定内膜蛋白 ElaB 的功能。 ElaB 增强对氧化应激和热应激的抵抗力，而 ElaB 失活则导致高持久细胞形成。我们还证明了 elaB 的转录受到稳定期 sigma 因子 RpoS 的直接调节。因此，我们的研究表明，小的内膜蛋白可能在应激反应过程中发挥重要的细胞作用。
ABSTRACT Host-associated bacteria, such as Escherichia coli, often encounter various host-related stresses, such as nutritional deprivation, oxidative stress, and temperature shifts. There is growing interest in searching for small endogenous proteins that mediate stress responses. Here, we characterized the small C-tail-anchored inner membrane protein ElaB in E. coli. ElaB belongs to a class of tail-anchored inner membrane proteins with a C-terminal transmembrane domain but lacking an N-terminal signal sequence for membrane targeting. Proteins from this family have been shown to play vital roles, such as in membrane trafficking and apoptosis, in eukaryotes; however, their role in prokaryotes is largely unexplored. Here, we found that the transcription of elaB is induced in the stationary phase in E. coli and stationary-phase sigma factor RpoS regulates elaB transcription by binding to the promoter of elaB. Moreover, ElaB protects cells against oxidative stress and heat shock stress. However, unlike membrane peptide toxins TisB and GhoT, ElaB does not lead to cell death, and the deletion of elaB greatly increases persister cell formation. Therefore, we demonstrate that disruption of C-tail-anchored inner membrane proteins can reduce stress resistance; it can also lead to deleterious effects, such as increased persistence, in E. coli. IMPORTANCE Escherichia coli synthesizes dozens of poorly understood small membrane proteins containing a predicted transmembrane domain. In this study, we characterized the function of the C-tail-anchored inner membrane protein ElaB in E. coli. ElaB increases resistance to oxidative stress and heat stress, while inactivation of ElaB leads to high persister cell formation. We also demonstrated that the transcription of elaB is under the direct regulation of stationary-phase sigma factor RpoS. Thus, our study reveals that small inner membrane proteins may have important cellular roles during the stress response.