副溶血性弧菌
分泌物
周质间隙
三型分泌系统
信号肽
微生物学
毒力
效应器
生物
细菌外膜
毒素
外毒素
细菌
细胞生物学
肽序列
生物化学
基因
大肠杆菌
遗传学
作者
Shigeaki Matsuda,Ryu Okada,Sarunporn Tandhavanant,Hirotaka Hiyoshi,Kazuyoshi Gotoh,Tetsuya Iida,Takao Kodama
出处
期刊:Nature microbiology
日期:2019-02-18
卷期号:4 (5): 781-788
被引量:33
标识
DOI:10.1038/s41564-019-0368-y
摘要
Many Gram-negative pathogens utilize dedicated secretion systems to export virulence factors such as exotoxins and effectors1-4. Several exotoxins are synthesized as precursors containing amino-terminal Sec signal peptides and are exported through the inner-membrane-bound Sec machinery to the periplasm, followed by secretion across the outer membrane to the exterior using a type II secretion system (T2SS)3,5. Here, we report that thermostable direct haemolysin (TDH), an exotoxin of the food-borne pathogen Vibrio parahaemolyticus, can be exported through the type III secretion system (T3SS), which engages in one-step secretion of effectors4, despite possessing a Sec signal peptide and being mainly secreted via the T2SS. Although the precursor of TDH is targeted to the Sec pathway, a fraction of mature TDH was observed to re-enter the bacterial cytoplasm. The N terminus of mature TDH comprises a T3SS signal sequence, allowing it to be loaded into the T3SS. We also show that T3SS-delivered TDH as an effector contributes to intestinal fluid accumulation in a rabbit diarrhoeal model of V. parahaemolyticus infection. Thus, our results show that an unconventional export mechanism for a bacterial toxin via the T3SS in tandem with the Sec machinery facilitates the virulence trait of V. parahaemolyticus.
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