Legionella pneumophila contains a type II general secretion pathway required for growth in amoebae as well as for secretion of the Msp protease

Infect Immun. 1999 Jul;67(7):3662-6. doi: 10.1128/IAI.67.7.3662-3666.1999.


We report the identification of a set of Legionella pneumophila genes that encode products with homology to proteins of the type II general secretion pathway of gram-negative bacteria. A strain containing a deletion-substitution mutation of two of these genes was unable to secrete the Msp protease. This strain was unable to multiply within the free-living amoeba Acanthamoeba castellanii yet was able to kill HL-60-derived macrophages. Because Msp is not required for growth in amoebae, other proteins which are important for growth in amoebae are likely secreted by this pathway.

MeSH terms

  • Acanthamoeba / microbiology*
  • Animals
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial*
  • Legionella pneumophila / physiology*
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism
  • Signal Transduction / genetics


  • Serine Endopeptidases

Associated data

  • GENBANK/AF111940