Involvement of vesicle-associated membrane protein 7 in human gastric epithelial cell vacuolation induced by Helicobacter pylori-produced VacA

Infect Immun. 2008 Jun;76(6):2296-303. doi: 10.1128/IAI.01573-07. Epub 2008 Mar 24.

Abstract

Helicobacter pylori-produced cytotoxin VacA induces intracellular vacuolation. The VacA-induced vacuole is assumed to represent the pathological status of intracellular trafficking. The fusion mechanism of the endosomes requires the formation of a tight complex between the Q-SNAREs and the R-SNAREs. We recently reported that syntaxin 7, a family member of the Q-SNARE protein, is involved in VacA-induced vacuole formation. In order to further elucidate the molecular mechanism, we identified the participation of vesicle-associated membrane protein 7 (VAMP7) as a partner of syntaxin 7. Immunocytochemistry revealed endogenous VAMP7 to be localized to the vacuoles induced by VacA. A Northern blotting study demonstrated that VacA intoxication increased VAMP7 mRNA in a time-dependent manner. VAMP7 was coimmunoprecipitated with syntaxin 7, and the amounts of endogenous VAMP7 and syntaxin 7 bound to syntaxin 7 and VAMP7, respectively, increased in response to VacA. The down-regulation of VAMP7 using small interfering RNA inhibited VacA-induced vacuolation, and the transient transfection of dominant-negative mutant VAMP7, the N-terminal domain of VAMP7, also inhibited the vacuolation. We therefore conclude that R-SNARE VAMP7 plays an important role in VacA-induced vacuolation as a partner of Q-SNARE syntaxin 7.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Line, Tumor
  • Down-Regulation
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology*
  • Gene Expression Regulation
  • Humans
  • Qa-SNARE Proteins / genetics
  • Qa-SNARE Proteins / metabolism
  • R-SNARE Proteins / genetics
  • R-SNARE Proteins / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Stomach / cytology*
  • Vacuoles / metabolism*
  • Vacuoles / microbiology

Substances

  • Bacterial Proteins
  • Qa-SNARE Proteins
  • R-SNARE Proteins
  • RNA, Messenger
  • VAMP7 protein, human
  • VacA protein, Helicobacter pylori