BamE directly interacts with BamA and BamD coordinating their functions.
BamE directly interacts with BamA and BamD coordinating their functions.
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BamE 直接与 BamA 和 BamD 交互，协调其功能。
DOI：
10.1111/mmi.15127
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发表时间：
2023
影响因子：
3.6
通讯作者：
Konovalova,Anna
中科院分区：
文献类型：
--
作者：
Kumar,Santosh;Konovalova,Anna
β-桶组装机（BAM）复合物促进革兰氏阴性菌外膜蛋白（OMP）的组装。Bam复合物是保守的，对细菌的生存力至关重要，由五个亚基组成，BamA-E。BamA是跨膜组分，其β-桶结构域横向打开以允许进入的OMP折叠和插入。其余的组成部分是调节性的，其中只有BamD是必不可少的。以往的研究表明BamB直接调节BamA，而BamE和BamC作为BamD的调节剂。然而，其功能的具体分子细节仍然未知。我们以前的研究表明，BamE在组装脂蛋白RcsF及其OMP伴侣之间的复合物中起着特殊的作用，这是胶囊合成调节剂（Rcs）应激反应所必需的。在这里，我们使用RcsF/OmpA作为模型底物来研究BamE功能。我们的研究结果挑战了目前认为BamE仅作为BamD调节剂的观点。我们发现BamE也直接与BamA相互作用。BamE与BamA和BamD的相互作用对于功能是重要的。我们的遗传和生化分析表明，BamE稳定BAM复合物，促进BamA和BamD之间的双向信号相互作用。当直接BamA/BamD通信受阻时，BamE功能变得至关重要。
The β‐barrel assembly machinery (Bam) complex facilitates the assembly of outer membrane proteins (OMPs) in gram‐negative bacteria. The Bam complex is conserved and essential for bacterial viability and consists of five subunits, BamA‐E. BamA is the transmembrane component, and its β‐barrel domain opens laterally to allow folding and insertion of incoming OMPs. The remaining components are regulatory, among which only BamD is essential. Previous studies suggested that BamB regulates BamA directly, while BamE and BamC serve as BamD regulators. However, specific molecular details of their functions remain unknown. Our previous research demonstrated that BamE plays a specialized role in assembling the complex between the lipoprotein RcsF and its OMP partners, required for the Regulator of Capsule Synthesis (Rcs) stress response. Here, we used RcsF/OmpA as a model substrate to investigate BamE function. Our results challenge the current view that BamE only serves as a BamD regulator. We show that BamE also directly interacts with BamA. BamE interaction with both BamA and BamD is important for function. Our genetic and biochemical analysis shows that BamE stabilizes the Bam complex and promotes bidirectional signaling interaction between BamA and BamD. This BamE function becomes essential when direct BamA/BamD communication is impeded.