Identification of YsaP, the Pilotin of the Yersinia enterocolitica Ysa Type III Secretion System.
Identification of YsaP, the Pilotin of the Yersinia enterocolitica Ysa Type III Secretion System.
复制标题
YsaP 的鉴定，小肠结肠炎耶尔森氏菌 Ysa III 型分泌系统的 Pilotin。
DOI：
10.1128/jb.00238-15
复制
发表时间：
2015
影响因子：
3.2
通讯作者：
Darwin,AndrewJ
中科院分区：
文献类型：
--
作者：
Rau,Reina;Darwin,AndrewJ
分泌素是在革兰氏阴性菌的复杂输出系统中发现的多聚体外膜孔形成蛋白。所有III型分泌系统（T3 SS）都有一种分泌素，其中之一是小肠结肠炎耶尔森氏菌染色体编码的Ysa T3 SS的YsaC分泌素。在某些情况下，作为外膜脂蛋白的毛素蛋白是其同源分泌素多聚化和/或定位于外膜所必需的。然而，如果分泌素多聚体错误定位到内膜，这可以触发保护性噬菌体休克蛋白（Psp）应激反应。在筛选抑制YsaC对apspnull菌株的毒性的突变期间，我们分离了几个预测增加Ysa致病性岛内YE 3559基因表达的独立突变。YE 3559，我们命名为ysaP，被预测为编码一个小的外膜脂蛋白，这个位置被膜分离证实。升高dysaP表达增加了YsaC的稳态水平，但使其对apspnull菌株的毒性降低，并且还降低了YsaC依赖的psp基因表达诱导。随后的实验表明，YsaP是不需要的YsaC多聚化，但需要多聚体定位到外膜。与此一致，aysaPnull突变损害了Ysa T3 SS的蛋白质输出。所有这些观察结果表明，YsaP是YsaC分泌素的先导素。这是第二个被鉴定为耶尔森氏菌的先导素，也是少数被描述为所有细菌的先导素之一。重要信息分泌素对许多细菌病原体的毒力是必不可少的，也在表面附着，运动和能力中发挥作用。这引起了人们对了解分泌素功能的极大兴趣。然而，它们与典型的外膜蛋白的根本差异引起了关于分泌素的各种问题，包括它们如何组装成外膜多聚体。Pilotin蛋白促进一些分泌素的组装，但只有少数Pilotin已被确定，减缓了理解分泌素组装的共同和独特特征的努力。这项研究提供了一个重要的进展，确定了一个新的成员的pilotin家族，也展示了一种方法，pilotin发现，可以广泛应用。
Secretins are multimeric outer membrane pore-forming proteins found in complex export systems in Gram-negative bacteria. All type III secretion systems (T3SSs) have a secretin, and one of these is the YsaC secretin of the chromosomally encoded Ysa T3SS of Yersinia enterocolitica. In some cases, pilotin proteins, which are outer membrane lipoproteins, are required for their cognate secretins to multimerize and/or localize to the outer membrane. However, if secretin multimers mislocalize to the inner membrane, this can trigger the protective phage shock protein (Psp) stress response. During a screen for mutations that suppress YsaC toxicity to apspnull strain, we isolated several independent mutations predicted to increase expression of the YE3559 gene within the Ysa pathogenicity island. YE3559, which we have namedysaP, is predicted to encode a small outer membrane lipoprotein, and this location was confirmed by membrane fractionation. ElevatedysaPexpression increased the steady-state level of YsaC but made it less toxic to apspnull strain, and it also decreased YsaC-dependent induction ofpspgene expression. Subsequent experiments showed that YsaP was not required for YsaC multimerization but was required for the multimers to localize to the outer membrane. Consistent with this, aysaPnull mutation compromised protein export by the Ysa T3SS. All these observations suggest that YsaP is the pilotin for the YsaC secretin. This is only the second pilotin to be characterized for Yersinia and one of only a small number of pilotins described for all bacteria.IMPORTANCESecretins are essential for the virulence of many bacterial pathogens and also play roles in surface attachment, motility, and competence. This has generated considerable interest in understanding how secretins function. However, their fundamental differences from typical outer membrane proteins have raised various questions about secretins, including how they are assembled into outer membrane multimers. Pilotin proteins facilitate the assembly of some secretins, but only a small number of pilotins have been identified, slowing efforts to understand common and distinct features of secretin assembly. This study provides an important advance by identifying a novel member of the pilotin family and also demonstrating a method of pilotin discovery that could be broadly applied.