Discussion

The Trypanosoma brucei mitochondrion undergoes extensive structural and metabolic remodeling during the parasite´s life cycle since the insect stage fully relies on oxidative phosphorylation (OXPHOS) to produce ATP while the mammalian bloodstream stage generates ATP by aerobic glycolysis. This complex developmental differentiation is exemplified during the flagellated protist’s migration from the tsetse fly midgut to the salivary glands, a process that can now be mimicked in vitro by overexpressing a single RNA binding protein. Here we demonstrate that the mitochondrial membrane potential and reactive oxygen species are increased at the early transition stages. Meanwhile, respiratory complexes III and IV become reduced and the electron flow is redirected from the OXPHOS pathway to an alternative oxidase. This coincides with the increased abundance of respiratory complex II and proline degradation enzymes that may act to provide ATP by substrate phosphorylation. Molecular triggers for this metabolic rewiring are being explored.