Cis and trans factors involved in apicoplast targeting in Toxoplasma gondii

J Parasitol. 2003 Aug;89(4):767-76. doi: 10.1645/GE-88R.

Abstract

Ribosomal subunit protein 9 (rps9) is a nuclearly encoded protein that resides in the apicoplast organelle of Toxoplasma gondii. Two cis-acting regions within the rps9 transit domain (amino acids 38-49 and 79-86), when combined with the rps9 signal sequence, were necessary and sufficient for apicoplast targeting. To investigate proteins interacting with the rps9 leader sequence, parasites expressing rps9 leader constructs fused to a glutathione S-transferase (GST) reporter were prepared, and proteins associated with the leader constructs were purified from extracts by affinity chromatography. In addition to GST-containing peptides, proteins with apparent masses of 92, 90, 86, and 160 kDa were purified. Mass spectrometry data suggested that the 92- and 90-kDa polypeptides appear to be subtilisin-like proteins, whereas the 86-kDa polypeptide was identified as the molecular chaperone BiP of T. gondii.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Carrier Proteins / analysis
  • Carrier Proteins / chemistry
  • Cells, Cultured
  • Chlorocebus aethiops
  • Chromatography, Affinity
  • Fibroblasts / parasitology
  • Fungal Proteins*
  • Glutathione Transferase / genetics
  • Glutathione Transferase / physiology
  • Green Fluorescent Proteins
  • Heat-Shock Proteins*
  • Humans
  • Indicators and Reagents / chemistry
  • Luminescent Proteins / chemistry
  • Mass Spectrometry
  • Molecular Chaperones / analysis
  • Molecular Chaperones / chemistry
  • Molecular Sequence Data
  • Organelles / chemistry*
  • Peptide Mapping
  • Protein Sorting Signals / physiology
  • Ribosomal Proteins / chemistry*
  • Ribosomal Proteins / genetics
  • Toxoplasma / genetics
  • Toxoplasma / physiology*
  • Toxoplasma / ultrastructure
  • Transfection
  • Vero Cells / parasitology

Substances

  • Carrier Proteins
  • Fungal Proteins
  • Heat-Shock Proteins
  • Indicators and Reagents
  • Luminescent Proteins
  • Molecular Chaperones
  • Protein Sorting Signals
  • Ribosomal Proteins
  • Su12 protein, Podospora anserina
  • Green Fluorescent Proteins
  • Glutathione Transferase
  • molecular chaperone GRP78