Localization of Phosphatidylinositol (3,4,5)-Trisphosphate to Phagosomes in Entamoeba histolytica Achieved Using Glutathione S-Transferase- and Green Fluorescent Protein-Tagged Lipid Biosensors

摘要: Entamoeba histolytica is an intestinal protozoan parasite that causes amoebic dysentery and liver abscess. Phagocytosis by the a critical virulence process, since it prerequisite for tissue invasion establishment of chronic infection. While roles many proteins regulate phagocytosis-related signaling events in E. have been characterized, functions lipids this cellular process remain largely unknown parasite. In other systems, phosphatidylinositol (3,4,5)-trisphosphate (PIP(3)), major product phosphoinositide 3 kinase (PI3-kinase) activity, essential phagocytosis. Pleckstrin homology (PH) domains are protein specifically bind to PIP(3). study, we utilized glutathione S-transferase (GST)- green fluorescent (GFP)-labeled PH as lipid biosensors characterize spatiotemporal aspects PIP(3) distribution during various endocytic processes histolytica. PIP(3)-specific accumulated at extending pseudopodia phagosomal cups trophozoites exposed erythrocytes but did not localize pinocytic compartments uptake fluid-phase marker, dextran. Our results suggest involved early stages phagosome formation addition, demonstrated exists high steady-state levels plasma membrane these levels, unlike those mammalian cells, abolished serum withdrawal. Finally, expression domain inhibited erythrophagocytosis enhanced motility, providing genetic evidence supporting role PI3-kinase