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.
Denny
P W
PW
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
Field
M C
MC
Smith
D F
DF
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