Galectin-3, a marker for vacuole lysis by invasive pathogens

Cell Microbiol. 2010 Apr 1;12(4):530-44. doi: 10.1111/j.1462-5822.2009.01415.x. Epub 2009 Nov 27.


Shigella bacteria invade macrophages and epithelial cells and following internalization lyse the phagosome and escape to the cytoplasm. Galectin-3, an abundant protein in macrophages and epithelial cells, belongs to a family of beta-galactoside-binding proteins, the galectins, with many proposed functions in immune response, development, differentiation, cancer and infection. Galectins are synthesized as cytosolic proteins and following non-classical secretion bind extracellular beta-galactosides. Here we analysed the localization of galectin-3 following entry of Shigella into the cytosol and detected a striking phenomenon. Very shortly after bacterial invasion, intracellular galectin-3 accumulated in structures in vicinity to internalized bacteria. By using immuno-electron microscopy analysis we identified galectin-3 in membranes localized in the phagosome and in tubules and vesicles that derive from the endocytic pathway. We also demonstrated that the binding of galectin-3 to host N-acetyllactosamine-containing glycans, was required for forming the structures. Accumulation of the structures was a type three secretion system-dependent process. More specifically, existence of structures was strictly dependent upon lysis of the phagocytic vacuole and could be shown also by Gram-positive Listeria and Salmonella sifA mutant. We suggest that galectin-3-containing structures may serve as a potential novel tool to spot vacuole lysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Sugars / metabolism
  • Animals
  • Biomarkers / analysis
  • Cell Line
  • Cricetinae
  • Cricetulus
  • Dogs
  • Galectin 3 / analysis*
  • Humans
  • Intracellular Membranes / chemistry
  • Listeria / pathogenicity
  • Mice
  • Microscopy, Immunoelectron
  • Phagosomes / chemistry*
  • Phagosomes / microbiology*
  • Polysaccharides / metabolism
  • Protein Binding
  • Salmonella / pathogenicity
  • Shigella / pathogenicity*


  • Amino Sugars
  • Biomarkers
  • Galectin 3
  • Polysaccharides
  • N-acetyllactosamine