Small outer-membrane lipoprotein, SmpA, is regulated by sigmaE and has a role in cell envelope integrity and virulence of Salmonella enterica serovar Typhimurium.
Small outer-membrane lipoprotein, SmpA, is regulated by sigmaE and has a role in cell envelope integrity and virulence of Salmonella enterica serovar Typhimurium.
复制标题
小外膜脂蛋白 (SmpA) 受 sigmaE 调节，在鼠伤寒沙门氏菌的细胞包膜完整性和毒力中发挥作用。
作者：
C. Lewis;Henrieta Skovierová;G. Rowley;B. Řežuchová;D. Homerová;A. Stevenson;Aileen Sherry;J. Kormanec;M. Roberts
SmpA 是一种小型外膜脂蛋白，是必需的 YaeT 外膜蛋白组装复合物的组成部分。在鼠伤寒沙门氏菌 (S. Typhimurium) 中，smpA 基因的表达受两个启动子 smpAp1 和 smpAp2 的指导。更远端的启动子 smpAp1 依赖于胞质外应激反应 sigma 因子 sigma(E)。在鼠伤寒沙门氏菌 SL1344 中构建了 smpA 无效突变体，该突变体比其野生型亲本在高温以及胆酸钠、SDS 加 EDTA 和疏水性抗生素利福平存在下的生长更敏感。鼠伤寒沙门氏菌中缺乏 SmpA 会引发 sigma(E) 依赖性应激反应。这些发现表明 smpA 突变体的外膜完整性发生了改变，这可能是由于外膜蛋白生物发生的缺陷所致。 SmpA 对于小鼠巨噬细胞的进入或存活并不重要；然而，鼠伤寒沙门氏菌 smpA 突变体在小鼠中通过口服和肠胃外感染途径减弱，并且 SmpA 似乎对于鼠伤寒沙门氏菌在全身部位的生长最为重要。
SmpA is a small outer-membrane lipoprotein that is a component of the essential YaeT outer-membrane protein assembly complex. In Salmonella enterica serovar Typhimurium (S. Typhimurium), expression of the smpA gene was shown to be directed by two promoters, smpAp1 and smpAp2. The more distal promoter, smpAp1, is dependent upon the extracytoplasmic stress response sigma factor sigma(E). An smpA null mutant was constructed in S. Typhimurium SL1344 and was shown to be more sensitive than its wild-type parent to growth at high temperature and in the presence of sodium cholate, SDS plus EDTA, and the hydrophobic antibiotic rifampicin. The lack of SmpA in S. Typhimurium elicits a sigma(E)-dependent stress response. These findings are indicative of altered outer-membrane integrity in the smpA mutant, probably due to a defect in outer-membrane protein biogenesis. SmpA was not important for entry or survival within murine macrophages; however, the S. Typhimurium smpA mutant was attenuated in mice by both the oral and parenteral routes of infection, and SmpA appeared to be most important for the growth of S. Typhimurium at systemic sites.