Efficient Uptake of Yersinia Pseudotuberculosis via Integrin Receptors Involves a Rac1-Arp 2/3 Pathway That Bypasses N-WASP Function

Mol Microbiol. 2001 Nov;42(3):689-703. doi: 10.1046/j.1365-2958.2001.02676.x.


Efficient uptake of Yersinia pseudotuberculosis into cultured mammalian cells is the result of high-affinity binding of invasin to beta1 chain integrins. We demonstrate here that uptake requires Rac1 and Arp 2/3 function. Bacterial uptake was stimulated by GTPgammaS, but was inhibited in mammalian cells transfected with the interfering Rac1-N17 derivative. Rac1 was found to be activated in response to integrin engagement by invasin, whereas Rac1 and Arp 2/3 were found to be intensely localized around phagosomes bearing bacteria, indicating a specific role for Rac1 signalling from the nascent phagosome to downstream effectors. To determine whether the Arp 2/3 complex was a component of this proposed pathway, cells overproducing various derivatives of Scar1/WAVE1, an Arp 2/3-binding protein, were analysed. Sequestration of Arp 2/3 away from the phagocytic cup as a result of Scar1/WAVE1 overproduction dramatically inhibited uptake. To determine whether signalling from Rac1 to Arp 2/3 occurred via N-WASP, uptake was analysed in a cell line lacking expression of WASP and N-WASP. Uptake was unaffected by the absence of these proteins, indicating that beta1 integrin signalling from Rac1 to Arp 2/3 can occur in the absence of N-WASP function.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actins / metabolism
  • Adhesins, Bacterial*
  • Animals
  • Bacterial Proteins / metabolism
  • COS Cells
  • Cell Line
  • Cell Membrane Permeability
  • Chlorocebus aethiops
  • Cytoskeletal Proteins*
  • Drug Combinations
  • Humans
  • Integrin beta1 / metabolism*
  • Mice
  • Nerve Tissue Proteins / metabolism*
  • Oils
  • Phagosomes / microbiology
  • Phenols
  • Receptors, Cell Surface / metabolism*
  • Wiskott-Aldrich Syndrome Protein, Neuronal
  • Yersinia pseudotuberculosis / pathogenicity*
  • Yersinia pseudotuberculosis Infections / microbiology
  • rac1 GTP-Binding Protein / metabolism*


  • ACTR2 protein, human
  • ACTR3 protein, human
  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actins
  • Actr2 protein, mouse
  • Actr3 protein, mouse
  • Adhesins, Bacterial
  • Bacterial Proteins
  • Cytoskeletal Proteins
  • Drug Combinations
  • Integrin beta1
  • Nerve Tissue Proteins
  • Oils
  • P & S Liquid
  • Phenols
  • Receptors, Cell Surface
  • WASL protein, human
  • Wasl protein, mouse
  • Wiskott-Aldrich Syndrome Protein, Neuronal
  • invasin, Yersinia
  • rac1 GTP-Binding Protein