Mapping the mitochondria across life's family tree reveals new drug targets and evolutionary secrets

Scientists at the Broad Institute, Harvard Medical School, and partner institutions have produced the most sweeping catalog of mitochondrial proteins ever assembled, spanning a model plant and five single-celled parasites that collectively sicken millions of people each year. Published across nine papers in Cell and related journals, the MitoCarta Tree of Life project used cutting-edge mass spectrometry to map which proteins end up inside the mitochondria of each organism — and the results are full of surprises.

Among the standout findings: Giardia (which causes diarrheal disease) has a stripped-down mitochondrion with just 59 proteins and no energy-producing capability, while Leishmania and Trypanosoma have mitochondrial proteomes 50% larger than humans'. The team also identified many mitochondrial proteins in pathogens that are absent from human mitochondria — making them promising targets for new drugs against neglected tropical diseases.

Key Takeaways:

• Many pathogen-specific mitochondrial proteins could serve as novel drug targets for diseases like leishmaniasis, trypanosomiasis, and babesiosis
• Machine-learning tools retrained on the new data helped reconstruct the evolutionary timeline, supporting the idea that mitochondria appeared late in eukaryotic evolution
• Methods developed for Babesia (a tick-borne, malaria-like pathogen spreading in New England) may also apply to malaria and toxoplasmosis research

Why it matters: Understanding how mitochondria differ across species doesn't just answer deep evolutionary questions — it opens the door to precision therapies that target parasites without harming human cells, a critical need for diseases that disproportionately affect low-income populations worldwide.