Research School of Biology, Australian National University, Canberra, Australia
Esther Rajendran
Research School of Biology, Australian National University, Canberra, Australia
Edwin T Tjhin
Research School of Biology, Australian National University, Canberra, Australia
Laura F Dagley
The Walter and Eliza Hall Institute of Medical Research, Victoria, Australia; Department of Medical Biology, University of Melbourne, Victoria, Australia
Vincent YT Aw
Research School of Biology, Australian National University, Canberra, Australia
Pierre Faou
Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia
Andrew I Webb
The Walter and Eliza Hall Institute of Medical Research, Victoria, Australia; Department of Medical Biology, University of Melbourne, Victoria, Australia
Christopher J Tonkin
The Walter and Eliza Hall Institute of Medical Research, Victoria, Australia; Department of Medical Biology, University of Melbourne, Victoria, Australia
The mitochondrion of apicomplexan parasites is critical for parasite survival, although the full complement of proteins that localize to this organelle has not been defined. Here we undertake two independent approaches to elucidate the mitochondrial proteome of the apicomplexan Toxoplasma gondii. We identify approximately 400 mitochondrial proteins, many of which lack homologs in the animals that these parasites infect, and most of which are important for parasite growth. We demonstrate that one such protein, termed TgApiCox25, is an important component of the parasite cytochrome c oxidase (COX) complex. We identify numerous other apicomplexan-specific components of COX, and conclude that apicomplexan COX, and apicomplexan mitochondria more generally, differ substantially in their protein composition from the hosts they infect. Our study highlights the diversity that exists in mitochondrial proteomes across the eukaryotic domain of life, and provides a foundation for defining unique aspects of mitochondrial biology in an important phylum of parasites.
