Leishmania donovani lipophosphoglycan causes periphagosomal actin accumulation: correlation with impaired translocation of PKCalpha and defective phagosome maturation.
Lipophosphoglycan (LPG) is the major surface glycoconjugate of Leishmania donovani promastigotes. The repeating disaccharide-phosphate units of LPG are crucial for promastigote survival inside macrophages and establishment of infection. LPG has a number of effects on the host cell, including inhibition of PKC activity, inhibition of nitric oxide production and altered expression of cytokines. LPG also inhibits phagosomal maturation, a process requiring depolymerization of periphagosomal F-actin. In the present study, we have characterized the dynamics of F-actin during the phagocytosis of L. donovani promastigotes in J774 macrophages. We observed that F-actin accumulated progressively around phagosomes containing wild-type L. donovani promastigotes during the first hour of phagocytosis. Using LPG-defective mutants and yeast particles coated with purified LPG, we obtained evidence that this effect could be attributed to the repeating units of LPG. LPG also disturbed cortical actin turnover during phagocytosis. The LPG-dependent accumulation of periphagosomal F-actin correlated with an impaired recruitment of the lysosomal marker LAMP1 and PKCalpha to the phagosome. Accumulation of periphagosomal F-actin during phagocytosis of L. donovani promastigotes may contribute to the inhibition of phagosomal maturation by physically preventing vesicular trafficking to and from the phagosome.
Holm A
Division of Medical Microbiology, Department of Health and Environment, Faculty of Health Sciences, Linköping University, S-581 85 Linköping, Sweden. asaholm@hem.passagen.se
Tejle
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Magnusson
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Descoteaux
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Rasmusson
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D000199:Actins / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002478:Cells, Cultured; D006028:Glycosphingolipids / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D007893:Leishmania donovani / Q000502:physiology*; D052118:Lysosomal-Associated Membrane Protein 1; D051907:Lysosomal Membrane Proteins; D008264:Macrophages / Q000469:parasitology; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D009154:Mutation; D010587:Phagocytosis; D010588:Phagosomes / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D021381:Protein Transport; D015003:Yeasts
D000199:Actins; D015703:Antigens, CD; D006028:Glycosphingolipids; D007527:Isoenzymes; D052118:Lysosomal-Associated Membrane Protein 1; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; C008290:lipophosphonoglycan; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha