Final Activity Report Summary - MIPCHIP (Mitochondrial protein characterisation and interaction prediction)
The canonical function of mitochondria in most textbooks is oxidative phosphorylation. However, many parasitic eukaryotes live in low oxygen environments where this cannot occur, yet they still keep their mitochondria, although they are often called mitosomes or hydrogenosomes. To understand why we carried out an exhaustive computational analysis of the genomes of a sample of eukaryotes that live under different conditions.
The results, organised into a relational database, have provided the clearest picture yet of how mitochondria evolve under contrasting host lifestyles. From the results it is clear that reductive evolution, whereby organelles have lost biochemical pathways or structural proteins, has occurred repeatedly and independently for different eukaryotes. As predicted, the genes for oxidative phosphorylation are commonly lost. What was surprising, however, is just how few proteins are strongly conserved. For example, the only metabolic pathway that appears to be conserved on all genomes, is one for the biosynthesis of iron-sulphur clusters. This is already known to be an essential feature of yeast mitochondria but our work shows that it may be a fundamental metabolic reason for why all eukaryotic cells have kept mitochondria. Experimental work is underway to test this hypothesis.
The results, organised into a relational database, have provided the clearest picture yet of how mitochondria evolve under contrasting host lifestyles. From the results it is clear that reductive evolution, whereby organelles have lost biochemical pathways or structural proteins, has occurred repeatedly and independently for different eukaryotes. As predicted, the genes for oxidative phosphorylation are commonly lost. What was surprising, however, is just how few proteins are strongly conserved. For example, the only metabolic pathway that appears to be conserved on all genomes, is one for the biosynthesis of iron-sulphur clusters. This is already known to be an essential feature of yeast mitochondria but our work shows that it may be a fundamental metabolic reason for why all eukaryotic cells have kept mitochondria. Experimental work is underway to test this hypothesis.