Inactivation of Rho GTPases by Burkholderia cenocepacia Induces a WASH-Mediated Actin Polymerization that Delays Phagosome Maturation

Cell Rep. 2020 Jun 2;31(9):107721. doi: 10.1016/j.celrep.2020.107721.

Abstract

Burkholderia cenocepacia is an opportunistic bacterial pathogen that causes severe pulmonary infections in cystic fibrosis and chronic granulomatous disease patients. B. cenocepacia can survive inside infected macrophages within the B. cenocepacia-containing vacuole (BcCV) and to elicit a severe inflammatory response. By inactivating the host macrophage Rho GTPases, the bacterial effector TecA causes depolymerization of the cortical actin cytoskeleton. In this study, we find that B. cenocepacia induces the formation of large cytosolic F-actin clusters in infected macrophages. Cluster formation requires the nucleation-promoting factor WASH, the Arp2/3 complex, and TecA. Inactivation of Rho GTPases by bacterial toxins is necessary and sufficient to induce the formation of the cytosolic actin clusters. By hijacking WASH and Arp2/3 activity, B. cenocepacia disrupts interactions with the endolysosomal system, thereby delaying the maturation of the BcCV.

Keywords: Arp2/3; Burkholderia cenocepacia; Clostridioides difficile; Rho GTPase; WASH; host-pathogen; macrophage; phagocytosis; phagosome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin-Related Protein 2-3 Complex / metabolism
  • Animals
  • Bacterial Toxins / metabolism
  • Bone Marrow Cells / cytology
  • Burkholderia cenocepacia / physiology*
  • Female
  • Lysosomes / metabolism
  • Macrophages / cytology
  • Macrophages / immunology
  • Macrophages / metabolism
  • Macrophages / microbiology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microfilament Proteins / deficiency
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Phagosomes / metabolism*
  • RAW 264.7 Cells
  • Vesicular Transport Proteins / deficiency
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • rho GTP-Binding Proteins / antagonists & inhibitors
  • rho GTP-Binding Proteins / metabolism*

Substances

  • Actin-Related Protein 2-3 Complex
  • Bacterial Toxins
  • Microfilament Proteins
  • Vesicular Transport Proteins
  • WASH protein, mouse
  • rho GTP-Binding Proteins