Profilin is required for sustaining efficient intra- and intercellular spreading of Shigella flexneri

J Biol Chem. 2000 Sep 15;275(37):28893-901. doi: 10.1074/jbc.M003882200.

Abstract

The ability of Shigella to mediate actin-based motility within the host cell is a prominent pathogenic feature of bacillary dysentery. The ability is dependent on the interaction of VirG with neural Wiskott-Aldrich syndrome protein (N-WASP), which in turn mediates recruitment of Arp2/3 complex and several actin-related proteins. In the present study, we show that profilin I is essential to the rapid movement of Shigella in epithelial cells, for which the capacity of profilin to interact with G-actin and N-WASP is critical. In COS-7 cells overexpressing either mutated profilin H119E, which failed to bind G-actin, or H133S, which is unable to interact with poly-l-proline, Shigella motility was significantly inhibited. Similarly, depletion of profilin from Xenopus egg extracts resulted in a decrease in bacterial motility that was completely rescued by adding back profilin I but not H119E or H133S. In COS-7 cells overexpressing a N-WASP mutant lacking the proline-rich domain (Deltap) unable to interact with profilin, the actin tail formation of intracellular Shigella was inhibited. In N-WASP-depleted extracts, addition of Deltap but not full-length N-WASP was unable to restore the bacterial motility. Furthermore, in a plaque formation assay with Madin-Darby canine kidney cell monolayers infected by Shigella, Madin-Darby canine kidney cells stably expressing H119E, H133S, or Deltap reduced the bacterial cell-to-cell spreading. These results indicate that profilin I associated with N-WASP is an essential host factor for sustaining efficient intra- and intercellular spreading of Shigella.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Bacterial Proteins
  • COS Cells
  • Contractile Proteins*
  • DNA-Binding Proteins / physiology
  • Dogs
  • Microfilament Proteins / physiology*
  • Movement
  • Nerve Tissue Proteins / physiology
  • Profilins
  • Rabbits
  • Shigella flexneri / physiology*
  • Transcription Factors / physiology
  • Wiskott-Aldrich Syndrome Protein, Neuronal
  • Xenopus

Substances

  • Actins
  • Bacterial Proteins
  • Contractile Proteins
  • DNA-Binding Proteins
  • Microfilament Proteins
  • Nerve Tissue Proteins
  • Profilins
  • Transcription Factors
  • Wiskott-Aldrich Syndrome Protein, Neuronal
  • virG protein, Shigella flexneri