GPI-anchored proteins and glycoconjugates segregate into lipid rafts in Kinetoplastida.
The plasma membranes of the divergent eukaryotic parasites, Leishmania and Trypanosoma, are highly specialised, with a thick coat of glycoconjugates and glycoproteins playing a central role in virulence. Unusually, the majority of these surface macro-molecules are attached to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. In mammalian cells and yeast, many GPI-anchored molecules associate with sphingolipid and cholesterol-rich detergent-resistant membranes, known as lipid rafts. Here we show that GPI-anchored parasite macro-molecules (but not the dual acylated Leishmania surface protein (hydrophilic acylated surface protein) or a subset of the GPI-anchored glycoinositol phospholipid glycolipids) are enriched in a sphingolipid/sterol-rich fraction resistant to cold detergent extraction. This observation is consistent with the presence of functional lipid rafts in these ancient, highly polarised organisms.
Wellcome Trust Laboratories for Molecular Parasitology, Department of Biochemistry, Imperial College of Science, Technology and Medicine, SW7 1AZ, London, UK. p.w.denny@ic.ac.uk
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Denny
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Field
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Smith
D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D003080:Cold Temperature; D003902:Detergents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006001:Glycoconjugates / Q000737:chemistry / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism*; D018320:Leishmania major / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D017830:Octoxynol / Q000494:pharmacology; D013107:Sphingolipids / Q000737:chemistry / Q000378:metabolism*; D013261:Sterols / Q000737:chemistry / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000737:chemistry / Q000378:metabolism*
D003902:Detergents; D006001:Glycoconjugates; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D013107:Sphingolipids; D013261:Sterols; D017830:Octoxynol; D002784:Cholesterol