• The team flagged mitochondrial proteins present in parasites but missing in people—candidate drug targets for neglected tropical diseases.
• A retrained machine-learning model now predicts mitoproteomes for hundreds of species, supporting the case that mitochondria appeared relatively late in eukaryotic evolution, after the ancestral cell had already built other complex machinery.
• More than half of the cataloged proteins carry no assigned function, opening a long research agenda.

What did each organism reveal?

Giardia's mitochondrion contains just 59 proteins and cannot make energy—a "remnant" organelle, the team argues, that challenges the textbook view of mitochondria as cell powerhouses.

Babesia, a tick-borne parasite spreading into New England with warming winters, yielded new methods the team expects will also work on malaria and toxoplasmosis pathogens.

Acanthamoeba, which causes blindness in contact lens wearers, runs the most complex respiratory machinery observed in any organism. Team member Jon Stefely's experiments showed its mitochondria switch between oxygen-using and oxygen-free respiration, possibly an ancient adaptation to fluctuating primordial seas.

Arabidopsis contributed the most complete plant mitoproteome on record.

Leishmania and Trypanosoma carry mitoproteomes about 50% larger than humans and packed with parasite-specific proteins—another set of candidate drug targets.

What does the work mean for drug discovery?

Senior computational scientist Sarah Calvo at the Broad framed the larger aim: "This project is one step in the larger scientific effort to use the existing diversity on Earth as a stepping stone toward answering one of the deepest questions: How did complex life evolve on our planet?"

For practitioners, the immediate value sits at mitocarta.org, where the consortium posted every dataset. Tropical-disease researchers gain a shortlist of parasite-only mitochondrial proteins to screen. Cell biologists gain a reference spanning 2 billion years of organelle evolution. The Broad's Proteomics Platform, directed by Namrata Udeshi, ran the mass spectrometry. "The speed and scale of this project would not have been possible without the platform's expertise in state-of-the-art, next-generation proteomic technology," she said.

The study, published in August 2026 in Cell (DOI: 10.1016/j.cell.2026.08.029), marks a baseline—Mootha and his co-leaders now treat comparative mitochondrial biology as its own field, not a side question.