CsgE is a curli secretion specificity factor that prevents amyloid fibre aggregation.
CsgE is a curli secretion specificity factor that prevents amyloid fibre aggregation.
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DOI：
10.1111/j.1365-2958.2011.07706.x
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发表时间：
2011-07
影响因子：
3.6
通讯作者：
Chapman MR
中科院分区：
文献类型：
--
作者：
Nenninger AA;Robinson LS;Hammer ND;Epstein EA;Badtke MP;Hultgren SJ;Chapman MR
卷曲是由大肠杆菌产生的细胞外淀粉样纤维，其对于生物膜形成和粘附到生物和非生物表面至关重要。CsgA和CsgB分别是主要的和次要的卷曲亚基，而CsgE、CsgF和CsgG指导卷曲亚基的细胞外定位和组装成纤维。CsgA和CsgB的分泌和稳定性依赖于外膜脂蛋白CsgG。在这里，我们确定了CsgG和CsgE之间的功能相互作用curli分泌。我们发现，CsgG过表达恢复curli生产curli诱导条件下的csgE菌株。在抗生素敏感性和蛋白分泌测定中，CsgG表达单独允许红霉素和小周质蛋白跨外膜易位。CsgE与CsgG的共表达阻断了非特异性蛋白和抗生素穿过外膜。然而，CsgE不阻断含有CsgA（A22）的22个氨基酸推定外膜分泌信号的蛋白质的分泌。最后，使用纯化的蛋白质，我们发现CsgE抑制CsgA自组装成淀粉样纤维。总的来说，这些数据表明CsgE为卷曲分泌孔CsgG提供底物特异性，并直接作用于分泌底物CsgA以防止过早的亚基组装。
Curli are extracellular amyloid fibers produced by Escherichia coli that are critical for biofilm formation and adhesion to biotic and abiotic surfaces. CsgA and CsgB are the major and minor curli subunits, respectively, while CsgE, CsgF, and CsgG direct the extracellular localization and assembly of curli subunits into fibers. The secretion and stability of CsgA and CsgB are dependent on the outer membrane lipoprotein CsgG. Here, we identified functional interactions between CsgG and CsgE during curli secretion. We discovered that CsgG overexpression restored curli production to a csgE strain under curli-inducing conditions. In antibiotic sensitivity and protein secretion assays, CsgG expression alone allowed translocation of erythromycin and small periplasmic proteins across the outer membrane. Co-expression of CsgE with CsgG blocked non-specific protein and antibiotic passage across the outer membrane. However, CsgE did not block secretion of proteins containing a 22 amino acid putative outer membrane secretion signal of CsgA (A22). Finally, using purified proteins, we found that CsgE prohibited the self-assembly of CsgA into amyloid fibers. Collectively, these data indicate that CsgE provides substrate specificity to the curli secretion pore CsgG, and acts directly on the secretion substrate CsgA to prevent premature subunit assembly.
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影响因子：
5.6
作者：
Collinson, SK;Parker, JMR;Kay, WW
通讯作者：
Kay, WW
影响因子：
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作者：
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Koronakis, V
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Frieden, C
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