Shigella interactions with the actin cytoskeleton in the absence of Ena/VASP family proteins

Cell Microbiol. 2004 Apr;6(4):355-66. doi: 10.1046/j.1462-5822.2003.00359.x.

Abstract

Shigella move through the cytosol of infected cells by assembly of a propulsive actin tail at one end of the bacterium. Vasodilator-stimulated phosphoprotein (VASP), a member of the Ena/VASP family of proteins, is important in cellular actin dynamics and is present on intracellular Shigella. VASP binds both profilin, an actin monomer-binding protein, and vinculin, a component of intercellular contacts that also binds the Shigella actin assembly protein IcsA. It has been postulated that VASP might serve as a linker between vinculin and profilin on intracellular Shigella, thereby delivering profilin to the Shigella actin assembly machinery. We show that Shigella actin-based motility is unaltered in cells that are deficient for the Ena/VASP family of proteins. In these cells, Shigella form normal-appearing actin tails and move at rates that are comparable to the rates of bacterial movement in Ena/VASP-deficient cells complemented with the Ena/VASP family member Mena. Finally, whereas vinculin can bind the Arp2/3 complex, we show that Arp2/3 recruitment to Shigella is not correlated with vinculin recruitment, indicating that the role of vinculin in Shigella motility is not recruitment of Arp2/3. Thus, although VASP is recruited to the surface of intracellular Shigella, it is not essential for Shigella actin-based motility.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / physiology*
  • Animals
  • Bacterial Proteins / physiology*
  • Carrier Proteins / metabolism
  • Cell Adhesion Molecules / physiology
  • Cells, Cultured
  • Contractile Proteins / metabolism
  • Cytoplasm / microbiology
  • Cytoskeletal Proteins / physiology*
  • Fibroblasts
  • Humans
  • Microfilament Proteins / metabolism
  • Movement
  • Phosphoproteins / analysis
  • Phosphoproteins / physiology
  • Profilins
  • Shigella flexneri / cytology
  • Shigella flexneri / physiology*
  • Vinculin / metabolism

Substances

  • Actins
  • Bacterial Proteins
  • Carrier Proteins
  • Cell Adhesion Molecules
  • Contractile Proteins
  • Cytoskeletal Proteins
  • Enah protein, mouse
  • Microfilament Proteins
  • PFN1 protein, human
  • Phosphoproteins
  • Profilins
  • vasodilator-stimulated phosphoprotein
  • Vinculin