Glycolipid precursors for the membrane anchor of Trypanosoma brucei variant surface glycoproteins. II. Lipid structures of phosphatidylinositol-specific phospholipase C sensitive and resistant glycolipids

Journal Article · Sun Apr 15 00:00:00 EDT 1990 · Journal of Biological Chemistry; (USA)

OSTI ID:7118065

Mayor, S; Menon, A K; Cross, G A ^[1]

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1. Rockefeller Univ., New York, NY (USA)

A common diagnostic feature of glycosylinositol phospholipid (GPI)-anchored proteins is their release from the membrane by a phosphatidylinositol-specific phospholipase C (PI-PLC). However, some GPI-anchored proteins are resistant to this enzyme. The best characterized example of this subclass is the human erythrocyte acetylcholinesterase, where the structural basis of PI-PLC resistance has been shown to be the acylation of an inositol hydroxyl group(s). Both PI-PLC-sensitive and resistant GPI-anchor precursors (P2 and P3, respectively) have been found in Trypanosoma brucei, where the major surface glycoprotein is anchored by a PI-PLC-sensitive glycolipid anchor. The accompanying paper shows that P2 and P3 have identical glycans, indistinguishable from the common core glycan found on all the characterized GPI protein anchors. This paper shows that the single difference between P2 and P3, and the basis for the PI-PLC insusceptibility of P3, is a fatty acid, ester-linked to the inositol residue in P3. The inositol-linked fatty acid can be removed by treatment with mild base to restore PI-PLC sensitivity. Biosynthetic labeling experiments with (3H)palmitic acid and (3H)myristic acid show that (3H)palmitic acid specifically labels the inositol residue in P3 while (3H)myristic acid labels the diacylglycerol portion. Possible models to account for the simultaneous presence of PI-PLC-resistant and sensitive glycolipids are discussed in the context of available information on the biosynthesis of GPI-anchors.

• OSTI ID: 7118065
• Journal Information: Journal of Biological Chemistry; (USA), Vol. 265:11; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLYCOPROTEINS
MOLECULAR STRUCTURE
CELL MEMBRANES
GLUCOSAMINE
HEXADECANOIC ACID
LIPASES
TETRADECANOIC ACID
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TRYPANOSOMA
AMINES
ANIMALS
CARBOHYDRATES
CARBOXYLESTERASES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHROMATOGRAPHY
ENZYMES
ESTERASES
HEXOSAMINES
HEXOSES
HYDROGEN COMPOUNDS
HYDROLASES
INVERTEBRATES
ISOTOPE APPLICATIONS
MASTIGOPHORA
MEMBRANES
MICROORGANISMS
MONOCARBOXYLIC ACIDS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARASITES
PROTEINS
PROTOZOA
SACCHARIDES
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques