Cell-free fusion of bacteria-containing phagosomes with endocytic compartments.
Uptake of microorganisms by professional phagocytic cells leads to formation of a new subcellular compartment, the phagosome, which matures by sequential fusion with early and late endocytic compartments, resulting in oxidative and nonoxidative killing of the enclosed microbe. Few tools are available to study membrane fusion between phagocytic and late endocytic compartments in general and with pathogen-containing phagosomes in particular. We have developed and applied a fluorescence microscopy assay to study fusion of microbe-containing phagosomes with different-aged endocytic compartments in vitro. This revealed that fusion of phagosomes containing nonpathogenic Escherichia coli with lysosomes requires Rab7 and SNARE proteins but not organelle acidification. In vitro fusion experiments with phagosomes containing pathogenic Salmonella enterica serovar Typhimurium indicated that reduced fusion of these phagosomes with early and late endocytic compartments was independent of endosome and cytosol sources and, hence, a consequence of altered phagosome quality.
Cell Biology Institute, University of Bonn, Ulrich-Haberland-Strasse 61a, 53121 Bonn, Germany.
Ulrike
U
Becken
Andreas
A
Jeschke
Katharina
K
Veltman
Albert
A
Haas
D001419:Bacteria / Q000378:metabolism*; D001681:Biological Assay; D002451:Cell Compartmentation; D002474:Cell-Free System / Q000382:microbiology*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D006358:Hot Temperature; D007840:Latex; D008247:Lysosomes / Q000378:metabolism / Q000382:microbiology; D008561:Membrane Fusion; D050296:Microbial Viability; D008863:Microspheres; D010588:Phagosomes / Q000378:metabolism / Q000382:microbiology*; D050600:SNARE Proteins / Q000378:metabolism; D019779:Salmonella enterica / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
D007840:Latex; D050600:SNARE Proteins; D000090802:rab7 GTP-Binding Proteins; D020691:rab GTP-Binding Proteins