Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes.

TitlePentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes.
Publication TypeJournal Article
Year of Publication2007
AuthorsPusnik, M, Small, I, Read, LK, Fabbro, T, Schneider, A
JournalMol Cell Biol
Date Published2007 Oct
KeywordsAnimals, Humans, Mitochondria, Mitochondrial Proteins, Molecular Sequence Data, Oxidative Phosphorylation, Protozoan Proteins, Repetitive Sequences, Amino Acid, Ribosomes, RNA Interference, RNA, Ribosomal, Trypanosoma brucei brucei

The pentatricopeptide repeat (PPR), a degenerate 35-amino-acid motif, defines a novel eukaryotic protein family. Plants have 400 to 500 distinct PPR proteins, whereas other eukaryotes generally have fewer than 5. The few PPR proteins that have been studied have roles in organellar gene expression, probably via direct interaction with RNA. Here we show that the parasitic protozoan Trypanosoma brucei encodes 28 distinct PPR proteins, an extraordinarily high number for a nonplant organism. A comparative analysis shows that seven out of eight selected PPR proteins are mitochondrially localized and essential for oxidative phosphorylation. Six of these are required for the stabilization of mitochondrial rRNAs and, like ribosomes, are associated with the mitochondrial membranes. Furthermore, one of the PPR proteins copurifies with the large subunit rRNA. Finally, ablation of all of the PPR proteins that were tested induces degradation of the other PPR proteins, indicating that they function in concert. Our results show that a significant number of trypanosomal PPR proteins are individually essential for the maintenance and/or biogenesis of mitochondrial rRNAs.

Alternate JournalMol. Cell. Biol.
Citation Key10.1128/MCB.00708-07
PubMed ID17646387
PubMed Central IDPMC2099244
Grant ListR03 AI063237 / AI / NIAID NIH HHS / United States