Cholesterol-rich membrane rafts and Lyn are involved in phagocytosis during Pseudomonas aeruginosa infection.
The mechanism of phagocytosis of pathogens remains to be fully characterized. We report a novel phagocytosis pathway for Pseudomonas aeruginosa, which is initiated by cholesterol-rich membrane rafts and is dependent on Lyn, primarily an immune regulator with both positive and negative roles. Blocking of Lyn or blocking of cholesterol synthesis significantly inhibited phagocytosis by alveolar macrophages. We found that Lyn, via Src homology 2 and 3 domains, bound to and then activated PI3K and Akt to regulate intracellular routing of the engulfed P. aeruginosa. Further analysis indicates that Lyn and raft components entered in phagosomes and late lysosomes. Finally, respiratory burst was dependent on Lyn and membrane rafts, as confirmed by small interfering RNA and dominant-negative strategies. Our investigations demonstrate that Lyn along with membrane rafts plays a fundamental role in phagocytosis by alveolar macrophages during infection.
Kannan
Shibichakravarthy
S
Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
Audet
Aaron
A
Huang
Huang
H
Chen
Li-juan
LJ
Wu
Min
M
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D002478:Cells, Cultured; D002784:Cholesterol / Q000502:physiology*; D016676:Macrophages, Alveolar / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology; D021962:Membrane Microdomains / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology; D010588:Phagosomes / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D011552:Pseudomonas Infections / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016897:Respiratory Burst / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D019061:src-Family Kinases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
D002784:Cholesterol; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases