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Binding of anthrax toxin to its receptor is similar to alpha integrin-ligand interactions

Kenneth A Bradley1, Jeremy Mogridge, G Jonah

  • 1McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. kbradley@microbio.ucla.edu

The Journal of Biological Chemistry
|September 26, 2003
PubMed

Insights

Bacillus anthracis toxin entry into cells requires a specific metal ion-dependent adhesion site (MIDAS) on the anthrax toxin receptor (ATR) and divalent cations. The protective antigen

Area of Science:

  • Molecular biology
  • Pathogen-host interactions
  • Structural biology

Background:

  • Bacillus anthracis toxin is a key virulence factor causing anthrax symptoms.
  • Protective antigen (PA) mediates toxin entry by binding the anthrax toxin receptor (ATR).
  • The interaction involves the integrin-like inserted (I) domain of ATR.

Purpose of the Study:

  • To elucidate the molecular requirements for protective antigen binding to the anthrax toxin receptor.
  • To understand the role of metal ions and specific amino acid residues in this interaction.

Main Methods:

  • Investigated the role of the metal ion-dependent adhesion site (MIDAS) in ATR.
  • Assessed the necessity of divalent cations for toxin-receptor binding.
  • Analyzed the contribution of the Asp-683 carboxylate group of protective antigen.

Main Results:

  • Protective antigen binding to ATR requires an intact MIDAS and specific divalent cations.
  • The Asp-683 carboxylate group of protective antigen is critical for this interaction.
  • This interaction mimics known integrin-ligand binding mechanisms.

Conclusions:

  • The binding of Bacillus anthracis protective antigen to its receptor is a metal-dependent process.
  • Specific structural features of both the toxin and receptor are essential for cell entry.
  • Findings provide insights into pathogen-host interactions and potential therapeutic targets.

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