A glycosylphosphatidylinositol protein anchor from procyclic stage Trypanosoma brucei: lipid structure and biosynthesis. Academic Article uri icon

Overview

MeSH

  • Acylation
  • Animals
  • Autoradiography
  • Chromatography, Thin Layer
  • Electrophoresis, Polyacrylamide Gel
  • Fatty Acids
  • Glycosylphosphatidylinositols
  • Inositol
  • Molecular Structure
  • Phosphatidylinositol Diacylglycerol-Lyase
  • Phosphoinositide Phospholipase C
  • Phosphoric Diester Hydrolases

MeSH Major

  • Glycolipids
  • Membrane Glycoproteins
  • Phosphatidylinositols
  • Protozoan Proteins
  • Trypanosoma brucei brucei
  • Variant Surface Glycoproteins, Trypanosoma

abstract

  • Cells of the insect (procyclic) stage of the life cycle of the African trypanosome, Trypanosoma brucei, express an abundant stage-specific glycosylated phosphatidylinositol (GPI) anchored glycoprotein, the procyclic acidic repetitive protein (PARP). The anchor is insensitive to the action of bacterial phosphatidylinositol-specific phospholipase C (PI-PLC), suggesting that it contains an acyl-inositol. We have recently described the structure of a PI-PLC resistant glycosylphosphatidylinositol, PP1, which is specific to the procyclic stage, and have presented preliminary evidence that the phosphatidylinositol portion of the protein-linked GPI on PARP has a similar structure. In this paper we show, by metabolic labelling with [3H]fatty acids, that the PARP anchor contains palmitate esterified to inositol, and stearate at sn-1, in a monoacylglycerol moiety, a structure identical to PP1. Using pulse-chase labelling, we show that both fatty acids are incorporated into the GPI anchor from a large pool of metabolic precursors, rather than directly from acyl-CoA. We also demonstrate that the addition of the GPI anchor moiety to PARP is dependent on de novo protein synthesis, excluding the possibility that incorporation of fatty acids into PARP can occur by a remodelling of pre-existing GPI anchors. Finally we show that the phosphatidylinositol (PI) species that are utilized for GPI biosynthesis are a subpopulation of the cellular PI molecular species. We propose that these observations may be of general validity since several other eukaryotic membrane proteins (e.g. human erythrocyte acetylcholine esterase and decay accelerating factor) have been reported to contain palmitoylated inositol residues.

publication date

  • October 1991

has subject area

  • Acylation
  • Animals
  • Autoradiography
  • Chromatography, Thin Layer
  • Electrophoresis, Polyacrylamide Gel
  • Fatty Acids
  • Glycolipids
  • Glycosylphosphatidylinositols
  • Inositol
  • Membrane Glycoproteins
  • Molecular Structure
  • Phosphatidylinositol Diacylglycerol-Lyase
  • Phosphatidylinositols
  • Phosphoinositide Phospholipase C
  • Phosphoric Diester Hydrolases
  • Protozoan Proteins
  • Trypanosoma brucei brucei
  • Variant Surface Glycoproteins, Trypanosoma

Research

keywords

  • Journal Article

Identity

Language

  • eng

PubMed Central ID

  • PMC452981

PubMed ID

  • 1655402

Additional Document Info

start page

  • 2731

end page

  • 2739

volume

  • 10

number

  • 10