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Membrane depolarization prevents cell invasion by Bordetella pertussis adenylate cyclase toxin

A S Otero1, X B Yi, M C Gray

  • 1Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.

The Journal of Biological Chemistry
|April 28, 1995
PubMed

Insights

Adenylate cyclase toxin from Bordetella pertussis enters cardiac cells by utilizing the cell membrane's electrical potential. This voltage-dependent process facilitates toxin translocation across the membrane, impacting cellular function.

Area of Science:

  • Microbiology
  • Cell Biology
  • Biochemistry

Background:

  • Adenylate cyclase toxin (ACT) from Bordetella pertussis is a potent calmodulin-activated enzyme.
  • ACT enters eukaryotic cells and disrupts cellular signaling by converting ATP to cAMP.
  • The precise mechanism of ACT cell entry remains largely uncharacterized.

Purpose of the Study:

  • To elucidate the mechanism by which adenylate cyclase toxin enters cardiac myocytes.
  • To investigate the role of the plasma membrane's electrical potential in ACT intoxication.

Main Methods:

  • Cardiac myocytes were utilized to study toxin entry.
  • Electrophysiological techniques were employed to assess voltage dependence.
  • Toxin binding and translocation were analyzed in relation to membrane potential.

Main Results:

  • Adenylate cyclase toxin intoxication of cardiac myocytes is driven and controlled by the plasma membrane's electrical potential.
  • The voltage dependence of intoxication is similar to that of ion channels in excitable membranes.
  • This voltage-sensitive step occurs after toxin binding and involves catalytic domain translocation.

Conclusions:

  • The electrical potential across the plasma membrane is a critical factor in adenylate cyclase toxin entry into cardiac myocytes.
  • Understanding this voltage-sensitive translocation mechanism is key to comprehending Bordetella pertussis pathogenesis.
  • Further research into toxin-membrane interactions can inform therapeutic strategies.

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