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 a nd glycoproteins playing a central role in virulence. Unusually, the majori ty 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-ri ch detergent-resistant membranes, known as lipid rafts. Here we show that G PI-anchored parasite macro-molecules (but not the dual acylated Leishmania surface protein (hydrophilic acylated surface protein) or a subset of the G PI-anchored glycoinositol phospholipid glycolipids) are enriched in a sphin golipid/sterol-rich fraction resistant to cold detergent extraction. This o bservation is consistent with the presence of functional lipid rafts in the se ancient, highly polarised organisms. (C) 2001 Federation of European Bio chemical Societies. Published by Elsevier Science B.V. All rights reserved.