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A bacterial pore-forming toxin forms aggregates in cells that resemble those associated with neurodegenerative

Julie P M Viala1, Sofia N Mochegova, Nicole Meyer-Morse

  • 1Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.

Cellular Microbiology
|December 11, 2007
PubMed

Insights

Listeria monocytogenes secretes listeriolysin O (LLO), a toxin that helps bacteria invade cells. This study found LLO can form aggregates similar to those seen in neurodegenerative diseases.

Area of Science:

  • Microbiology
  • Cell Biology
  • Neuroscience

Background:

  • Listeria monocytogenes is a facultative intracellular bacterium.
  • Listeriolysin O (LLO) is a pore-forming toxin secreted by L. monocytogenes.
  • LLO facilitates bacterial escape into the host cell cytoplasm by disrupting the phagosomal membrane.

Purpose of the Study:

  • To investigate the intracellular localization of secreted LLO in infected host cells.
  • To characterize the nature and formation of LLO-containing structures within host cells.

Main Methods:

  • Immunofluorescence microscopy to visualize LLO localization.
  • Analysis of LLO aggregation and its dependence on LLO activity.
  • Biochemical characterization of protein aggregates containing LLO.

Main Results:

  • Secreted LLO was found to localize in distinct cellular compartments.
  • LLO forms perinuclear aggregates and accumulates in autophagosome-like structures.
  • Active LLO sequesters into large protein aggregates, also containing polyubiquitinated proteins and p62.

Conclusions:

  • Bacterial protein LLO can form aggregates within host cells.
  • These aggregates share characteristics with protein aggregates associated with neurodegenerative diseases.
  • This suggests a potential link between bacterial infection and host cellular protein aggregation pathways.

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