GPI-anchored Proteins and Free GPI Glycolipids of Procyclic FormTrypanosoma bruceiAre Nonessential for Growth, Are Required for Colonization of the Tsetse Fly, and Are Not the Only Components of the Surface Coat
- 1 December 2006
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 17 (12), 5265-5274
- https://doi.org/10.1091/mbc.e06-08-0702
Abstract
The procyclic form of Trypanosoma brucei exists in the midgut of the tsetse fly. The current model of its surface glycocalyx is an array of rod-like procyclin glycoproteins with glycosylphosphatidylinositol (GPI) anchors carrying sialylated poly-N-acetyllactosamine side chains interspersed with smaller sialylated poly-N-acetyllactosamine–containing free GPI glycolipids. Mutants for TbGPI12, deficient in the second step of GPI biosynthesis, were devoid of cell surface procyclins and poly-N-acetyllactosamine–containing free GPI glycolipids. This major disruption to their surface architecture severely impaired their ability to colonize tsetse fly midguts but, surprisingly, had no effect on their morphology and growth characteristics in vitro. Transmission electron microscopy showed that the mutants retained a cell surface glycocalyx. This structure, and the viability of the mutants in vitro, prompted us to look for non-GPI–anchored parasite molecules and/or the adsorption of serum components. Neither were apparent from cell surface biotinylation experiments but [3H]glucosamine biosynthetic labeling revealed a group of previously unidentified high apparent molecular weight glycoconjugates that might contribute to the surface coat. While characterizing GlcNAc-PI that accumulates in the TbGPI12 mutant, we observed inositolphosphoceramides for the first time in this organism.Keywords
This publication has 53 references indexed in Scilit:
- The Protozoan Inositol Phosphorylceramide SynthaseJournal of Biological Chemistry, 2006
- Role of the N-terminal domains of EP and GPEET procyclins in membrane targeting and the establishment of midgut infections by Trypanosoma bruceiMolecular and Biochemical Parasitology, 2004
- Ether Phospholipids and Glycosylinositolphospholipids Are Not Required for Amastigote Virulence or for Inhibition of Macrophage Activation by Leishmania majorJournal of Biological Chemistry, 2003
- Procyclin Null Mutants ofTrypanosoma bruceiExpress Free Glycosylphosphatidylinositols on Their SurfaceMolecular Biology of the Cell, 2003
- Secretory Pathway of Trypanosomatid ParasitesMicrobiology and Molecular Biology Reviews, 2002
- Multiple procyclin isoforms are expressed differentially during the development of insect forms of Trypanosoma bruceiJournal of Molecular Biology, 2001
- Identification of plasmenylethanolamine as a major component of the phospholipids of strain DM 28c of Trypanosoma cruziMolecular and Biochemical Parasitology, 1999
- Structural characterisation of two forms of procyclic acidic repetitive protein expressed by procyclic forms of Trypanosoma bruceiJournal of Molecular Biology, 1997
- Procyclin: an unusual immunodominant glycoprotein surface antigen from the procyclic stage of African trypanosomesMolecular and Biochemical Parasitology, 1988
- Ruthenium red and violet. III. Fine structure of the plasma membrane and extraneous coats in amoebae (A. proteus and chaos chaos)The Anatomical Record, 1971