RRC ID 56362
Author Matsuda S, Okada R, Tandhavanant S, Hiyoshi H, Gotoh K, Iida T, Kodama T.
Title Export of a Vibrio parahaemolyticus toxin by the Sec and type III secretion machineries in tandem.
Journal Nat Microbiol
Abstract 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.
Volume 4(5)
Pages 781-788
Published 2019-5-1
DOI 10.1038/s41564-019-0368-y
PII 10.1038/s41564-019-0368-y
PMID 30778145
MeSH Animals Bacterial Proteins / genetics Bacterial Proteins / metabolism* Bacterial Toxins / metabolism Biological Transport Female Hemolysin Proteins / metabolism* Humans Mice, Inbred C3H Rabbits Type III Secretion Systems / genetics Type III Secretion Systems / metabolism* Vibrio Infections / microbiology* Vibrio parahaemolyticus / genetics Vibrio parahaemolyticus / metabolism*
IF 14.633
Times Cited 7
Pathogenic bacteria