Daefler S, Russel M
The Rockefeller University, New York, NY 10021, USA.
Mol Microbiol. 1998 Jun;28(6):1367-80. doi: 10.1046/j.1365-2958.1998.00908.x.
The secretion of pathogenicity factors by Salmonella typhimurium is mediated by a type III secretion system that includes an outer membrane protein of the secretin family. Related secretins are also required for f1 phage assembly and type II secretion. When the C-terminal 43 amino acids of the S. typhimurium secretin InvG are added to f1 pIV, the chimeric f1 pIV-'InvG43 protein becomes dependent on the co-expression of another gene, invH, for function in phage assembly. [3H]-palmitic acid labelling, globomycin sensitivity and density gradient flotation were used to demonstrate that InvH is an outer membrane lipoprotein that is processed by signal peptidase II. A complex between chimeric f1 pIV-'InvG43 and InvH was demonstrated in vivo. InvH was shown to be required for the proper localization of InvG in the outer membrane and for the secretion of the virulence factor SipC. These results suggest that InvH and InvG are part of the functional outer membrane translocation complex in type III secretion systems.
鼠伤寒沙门氏菌致病因子的分泌由III型分泌系统介导，该系统包含分泌素家族的一种外膜蛋白。f1噬菌体组装和II型分泌也需要相关的分泌素。当将鼠伤寒沙门氏菌分泌素InvG的C末端43个氨基酸添加到f1 pIV时，嵌合的f1 pIV-“InvG43蛋白在噬菌体组装中的功能变得依赖于另一个基因invH的共表达。使用[3H]-棕榈酸标记、对球霉素的敏感性和密度梯度浮选来证明InvH是一种经信号肽酶II加工的外膜脂蛋白。在体内证明了嵌合的f1 pIV-“InvG43与InvH之间形成复合物。结果表明，InvH对于InvG在外膜中的正确定位以及毒力因子SipC的分泌是必需的。这些结果表明，InvH和InvG是III型分泌系统中功能性外膜转运复合物的一部分。
