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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
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Oligomerization is essential for apoptotic activity of Vibrio vulnificus hemolysin

Takashige Kashimoto1, Shunji Ueno, Hayato Ehara

  • 1Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan.

The Journal of Veterinary Medical Science
|November 6, 2009
PubMed

Insights

Oligomerization of Vibrio vulnificus hemolysin (VVH) is crucial for its ability to cause cell lysis and apoptosis. A non-oligomerized mutant showed significantly reduced apoptotic activity, confirming this essential role.

Area of Science:

  • Microbiology
  • Cell Biology
  • Toxicology

Background:

  • Vibrio vulnificus hemolysin (VVH) is a pore-forming toxin implicated in bacterial virulence.
  • VVH is known to induce both apoptosis and cell lysis in target cells.
  • The necessity of pore formation for VVH-induced apoptosis remains unclear.

Purpose of the Study:

  • To investigate whether pore formation is essential for VVH-induced apoptosis.
  • To compare the apoptotic and lytic activities of wild-type VVH and a non-oligomerized mutant.

Main Methods:

  • Chinese hamster ovary (CHO) cells were utilized as the target cell model.
  • A non-oligomerized mutant (F334I) of VVH was created by replacing phenylalanine 334 with isoleucine.
  • Apoptosis rates were measured and compared between cells treated with wild-type VVH and the F334I mutant.

Main Results:

  • Wild-type VVH induced apoptosis in 41.5 +/- 6.4% of CHO cells.
  • The F334I mutant exhibited significantly reduced apoptotic activity, causing only 0.4 +/- 0.8% apoptosis at the same concentration.
  • These findings indicate that oligomerization is critical for both lytic and apoptotic functions of VVH.

Conclusions:

  • Oligomerization is an essential step for the cell lytic activity of VVH.
  • Oligomerization is also essential for the apoptotic activity of VVH.
  • These results clarify the mechanism of VVH-induced cell death and its role in virulence.

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