Essential roles for GPI-anchored proteins in African trypanosomes revealed using mutants deficient in GPI8

Simon Lillico, Mark C Field, Pat Blundell, Graham H Coombs, Jeremy C Mottram

Research output: Contribution to journalArticlepeer-review

Abstract

The survival of Trypanosoma brucei, the causative agent of Sleeping Sickness and Nagana, is facilitated by the expression of a dense surface coat of glycosylphosphatidylinositol (GPI)-anchored proteins in both its mammalian and tsetse fly hosts. We have characterized T. brucei GPI8, the gene encoding the catalytic subunit of the GPI:protein transamidase complex that adds preformed GPI anchors onto nascent polypeptides. Deletion of GPI8 (to give Deltagpi8) resulted in the absence of GPI-anchored proteins from the cell surface of procyclic form trypanosomes and accumulation of a pool of non-protein-linked GPI molecules, some of which are surface located. Procyclic Deltagpi8, while viable in culture, were unable to establish infections in the tsetse midgut, confirming that GPI-anchored proteins are essential for insect-parasite interactions. Applying specific inducible GPI8 RNAi with bloodstream form parasites resulted in accumulation of unanchored variant surface glycoprotein and cell death with a defined multinuclear, multikinetoplast, and multiflagellar phenotype indicative of a block in cytokinesis. These data show that GPI-anchored proteins are essential for the viability of bloodstream form trypanosomes even in the absence of immune challenge and imply that GPI8 is important for proper cell cycle progression.
Original languageEnglish
Pages (from-to)1182-94
Number of pages13
JournalMolecular Biology of the Cell
Volume14
Issue number3
DOIs
Publication statusPublished - Mar 2003

Keywords

  • Amino Acid Sequence
  • Animals
  • Carbohydrate Sequence
  • Cell Adhesion Molecules
  • Cell Cycle
  • Glycosylphosphatidylinositols
  • Humans
  • Mannose
  • Molecular Sequence Data
  • Mutation
  • RNA Interference
  • Sequence Alignment
  • Trypanosoma brucei brucei
  • Trypanosomiasis, African
  • Tsetse Flies

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