title: Functional characterization of EpsC, a component of the type II secretion system, in the pathogenicity of Vibrio vulnificus.
abstract: EpsC, one of the components comprising the type II secretion system (T2SS), was isolated from a human-pathogenic bacterium, Vibrio vulnificus, to evaluate its role in eliciting virulence. An espC-deleted mutant of V. vulnificus displayed a reduced cytotoxicity to the human cell line HEp-2 and an attenuated virulence in a mouse model. This mutant exhibited dramatic defects in the secretion of diverse extracellular proteins, such as outer membrane proteins, transporters, and the known secreted factors, notably, a hemolysin (VvhA) and an elastase (VvpE). A defect in its secretion of proteins was restored by in trans complementation of the intact epsC gene. Analyses of cellular fractions revealed that VvhA and VvpE of the ΔepsC mutant were not excreted outside the cell but were present mainly in the periplasmic space. Examination of a V. vulnificus mutant deficient in TolC, a component of the T1SS, showed that it is not involved in the secretion of VvhA and VvpE but that it is necessary for the secretion of another major toxin of V. vulnificus, RtxA. Therefore, the T2SS is required for V. vulnificus pathogenicity, which is mediated by at least two secreted factors, VvhA and VvpE, via facilitating the secretion and exposure of these factors to host cells.
authors.affiliation: Department of Environmental Medical Biology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Hwang
authors.forename: Na Yeon
authors.initials: NY
authors.lastname: Lee
authors.forename: Juri
authors.initials: J
authors.lastname: Kim
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Lee
authors.forename: Kun-Soo
authors.initials: KS
authors.lastname: Kim
authors.forename: Kyu-Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Soon-Jung
authors.initials: SJ
authors.lastname: Park
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D058947:Bacterial Secretion Systems / Q000502:physiology*; D002460:Cell Line; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008099:Liver / Q000166:cytology / Q000382:microbiology; D051379:Mice; D010196:Pancreatic Elastase / Q000235:genetics / Q000378:metabolism*; D014735:Vibrio Infections / Q000382:microbiology*; D041261:Vibrio vulnificus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; C470630:VvhA protein, Vibrio vulnificus; D010196:Pancreatic Elastase