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Scientific article
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English

Role of magnesium and a phagosomal P-type ATPase in intracellular bacterial killing

Published inCellular microbiology, vol. 13, no. 2, p. 246-258
Publication date2011
Abstract

Bacterial ingestion and killing by phagocytic cells are essential processes to protect the human body from infectious microorganisms. However, only few proteins implicated in intracellular bacterial killing have been identified to date. We used Dictyostelium discoideum, a phagocytic bacterial predator, to study intracellular killing. In a random genetic screen we identified Kil2, a type V P-ATPase as an essential element for efficient intracellular killing of Klebsiella pneumoniae bacteria. Interestingly, kil2 knockout cells still killed efficiently several other species of bacteria, and did not show enhanced susceptibility to Mycobacterium marinum intracellular replication. Kil2 is present in the phagosomal membrane, and its structure suggests that it pumps cations into the phagosomal lumen. The killing defect of kil2 knockout cells was rescued by the addition of magnesium ions, suggesting that Kil2 may function as a magnesium pump. In agreement with this, kil2 mutant cells exhibited a specific defect for growth at high concentrations of magnesium. Phagosomal protease activity was lower in kil2 mutant cells than in wild-type cells, a phenotype reversed by the addition of magnesium to the medium. Kil2 may act as a magnesium pump maintaining magnesium concentration in phagosomes, thus ensuring optimal activity of phagosomal proteases and efficient killing of bacteria.

Keywords
  • Adenosine Triphosphatases/metabolism
  • Dictyostelium/metabolism/microbiology
  • Klebsiella pneumoniae/drug effects/growth & development
  • Magnesium/metabolism
  • Membrane Transport Proteins/genetics/metabolism
  • Microbial Viability/drug effects
  • Mycobacterium marinum/drug effects/growth & development
  • Phagosomes/metabolism/microbiology
  • Protozoan Proteins/genetics/metabolism
Research group
Citation (ISO format)
LELONG-FAVRE ALBORINI, Emmanuelle et al. Role of magnesium and a phagosomal P-type ATPase in intracellular bacterial killing. In: Cellular microbiology, 2011, vol. 13, n° 2, p. 246–258. doi: 10.1111/j.1462-5822.2010.01532.x
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Article (Published version)
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ISSN of the journal1462-5814
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