Ca2+-activated transbilayer movement of plasma membrane phospholipids in Leishmania donovani during ionomycin or thapsigargin stimulation

• Published in: Molecular and biochemical parasitology 2011-10, Vol.179 (2), p.59-68
• Main Authors: Weingärtner, Adrien, dos Santos, Marcos Gonzaga, Drobot, Björn, Pomorski, Thomas Günther
• Format: Article
• Language: English
• Subjects: adenosine triphosphate; Annexin A5 - metabolism; Calcium; Calcium - metabolism; Cell Membrane - metabolism; Flow Cytometry; Fluorescent Dyes - metabolism; humans; Ionomycin - pharmacology; Ionophore; Leishmania donovani; Leishmania donovani - drug effects; Leishmania donovani - metabolism; Leishmania donovani - pathogenicity; Lipid asymmetry; Lipid Bilayers - metabolism; Lipid Metabolism; macrophages; Microscopy, Confocal; parasites; parasitology; Phlebotominae; phosphatidylethanolamines; Phosphatidylethanolamines - metabolism; Phospholipid Transfer Proteins - metabolism; Plasma membrane; promastigotes; temperature; Thapsigargin - pharmacology
• ISSN: 0166-6851; 1872-9428
• DOI: 10.1016/j.molbiopara.2011.05.006

[Display omitted] ► Ionomycin and thapsigargin elevate intracellular Ca2+ in Leishmania donovani. ► Increase in cytosolic Ca2+ triggers loss of plasma membrane lipid asymmetry. ► Increase in cytosolic Ca2+ induces transbilayer redistribution of fluorescent lipids. ► Ca2+ release from intracellular compartments alone can trigger lipid redistribution. The protozoan parasite Leishmania causes serious infections in humans all over the world. After being inoculated into the skin through the bite of an infected sandfly, Leishmania promastigotes must gain entry into macrophages to initiate a successful infection. Specific, surface exposed phospholipids have been implicated in Leishmania–macrophage interaction but the mechanisms controlling and regulating the plasma membrane lipid distribution remains to be elucidated. Here, we provide evidence for Ca2+-induced phospholipid scrambling in the plasma membrane of Leishmania donovani. Stimulation of parasites with ionomycin increases intracellular Ca2+ levels and triggers exposure of phosphatidylethanolamine at the cell surface. We found that increasing intracellular Ca2+ levels with ionomycin or thapsigargin induces rapid transbilayer movement of NBD-labelled phospholipids in the parasite plasma membrane that is bidirectional, independent of cellular ATP and not specific to the polar lipid head group. The findings suggest the presence of a Ca2+-dependent lipid scramblase activity in Leishmania parasites. Our studies further show that lipid scrambling is not activated by rapid exposure of promastigotes to higher physiological temperature that increases intracellular Ca2+ levels.