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Arp2/3-independent assembly of actin by Vibrio type III effector VopL

Amy D B Liverman1, Hui-Chun Cheng, Jennifer E Trosky

  • 1Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA.

Proceedings of the National Academy of Sciences of the United States of America
|October 19, 2007
PubMed

Insights

The bacterial protein VopL from Vibrio parahaemolyticus (V. para) directly induces actin assembly, disrupting host cell structure during infection. This virulence factor is key to understanding bacterial pathogenesis and host-pathogen interactions.

Area of Science:

  • Microbiology
  • Cell Biology
  • Biochemistry

Background:

  • Microbial pathogens frequently target the host actin cytoskeleton for invasion and replication.
  • Vibrio parahaemolyticus (V. para) is a Gram-negative bacterium responsible for gastroenteritis, with emerging pandemic strains.
  • Understanding bacterial virulence factors is crucial for combating infectious diseases.

Purpose of the Study:

  • To investigate the role of the Vibrio parahaemolyticus type III secretion system effector, VopL, in modulating the host actin cytoskeleton.
  • To characterize the mechanism by which VopL induces actin assembly.
  • To identify VopL as a potential bacterial virulence factor.

Main Methods:

  • Genomic analysis of V. para to identify effector proteins.
  • Infection of HeLa cells with V. para and VopL transfection.
  • In vitro actin assembly assays using recombinant VopL.
  • Microscopy to observe actin fiber formation.

Main Results:

  • V. para infection induced VopL-dependent actin fiber formation in HeLa cells.
  • Transfection of VopL alone promoted actin stress fiber assembly.
  • Recombinant VopL potently induced actin filament assembly in vitro, independent of eukaryotic factors.
  • VopL possesses three Wiskott-Aldrich homology 2 domains and proline-rich motifs.

Conclusions:

  • Vibrio VopL is a bacterial virulence factor that directly induces actin polymerization.
  • VopL disrupts host actin homeostasis, contributing to pathogenesis during enteric infections.
  • This effector protein represents a novel target for therapeutic intervention against V. para infections.

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