Differential regulation of actin-activated nucleotidyl cyclase virulence factors by filamentous and globular actin

PLoS One. 2018 Nov 12;13(11):e0206133. doi: 10.1371/journal.pone.0206133. eCollection 2018.


Several bacterial pathogens produce nucleotidyl cyclase toxins to manipulate eukaryotic host cells. Inside host cells they are activated by endogenous cofactors to produce high levels of cyclic nucleotides (cNMPs). The ExoY toxin from Pseudomonas aeruginosa (PaExoY) and the ExoY-like module (VnExoY) found in the MARTX (Multifunctional-Autoprocessing Repeats-in-ToXin) toxin of Vibrio nigripulchritudo share modest sequence similarity (~38%) but were both recently shown to be activated by actin after their delivery to the eukaryotic host cell. Here, we further characterized the ExoY-like cyclase of V. nigripulchritudo. We show that, in contrast to PaExoY that requires polymerized actin (F-actin) for maximum activation, VnExoY is selectively activated by monomeric actin (G-actin). These two enzymes also display different nucleotide substrate and divalent cation specificities. In vitro in presence of the cation Mg2+, the F-actin activated PaExoY exhibits a promiscuous nucleotidyl cyclase activity with the substrate preference GTP>ATP≥UTP>CTP, while the G-actin activated VnExoY shows a strong preference for ATP as substrate, as it is the case for the well-known calmodulin-activated adenylate cyclase toxins from Bordetella pertussis or Bacillus anthracis. These results suggest that the actin-activated nucleotidyl cyclase virulence factors despite sharing a common activator may actually display a greater variability of biological effects in infected cells than initially anticipated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / chemistry
  • Actin Cytoskeleton / genetics*
  • Adenosine Triphosphate / chemistry
  • Adenylate Cyclase Toxin / chemistry*
  • Adenylate Cyclase Toxin / genetics
  • Bacillus anthracis / drug effects
  • Bacillus anthracis / pathogenicity
  • Bacterial Proteins / genetics
  • Bordetella pertussis / drug effects
  • Bordetella pertussis / pathogenicity
  • Eukaryotic Cells / drug effects*
  • Glucosyltransferases / genetics
  • Host-Pathogen Interactions / genetics
  • Humans
  • Pseudomonas aeruginosa / chemistry*
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / pathogenicity
  • Substrate Specificity
  • Toxins, Biological / chemistry
  • Toxins, Biological / genetics
  • Vibrio / drug effects
  • Vibrio / genetics
  • Vibrio / pathogenicity
  • Virulence Factors / chemistry
  • Virulence Factors / genetics


  • Adenylate Cyclase Toxin
  • Bacterial Proteins
  • Toxins, Biological
  • Virulence Factors
  • Adenosine Triphosphate
  • ExoY protein, bacteria
  • Glucosyltransferases

Grants and funding

This project was funded by the Institut Pasteur under PTR425 and PTR 43-16, by the ANR under ANR18-CE44-0004 and by CNRS UMR 3528. AB was supported by a stipend from the Pasteur - Paris University (PPU) International PhD Program. This work was supported by the French Infrastructure for Integrated Structural Biology (FRISBI) ANR-10-INBS-05. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.