What it is
Acanthamoeba castellanii, an amoeba that causes infectious blindness, sits in a key evolutionary outgroup to humans and fungi, and its divergent mitochondria are predicted to carry out both aerobic and anaerobic functions. The authors combined mitochondrial immunoprecipitation, density gradient purification, mass spectrometry, protein correlation profiling and microscopy to build a high-confidence inventory of its mitochondrial proteome. The resulting AcMitoCarta contains 1,122 proteins, 381 of which lack readily identifiable homologs in human and yeast mitochondria, and a complexome analysis highlights 20 macromolecular assemblies.
Why it matters
A detailed account of this organelle's energy machinery, its activities and their regulation had been lacking. Complementary proteomic and transcriptomic profiling shows that oxygen extensively rewires that machinery, including the induction, when oxygen is absent, of an anaerobic pathway running from pyruvate:ferredoxin oxidoreductase to a hydrogenase. The authors show experimentally that the amoeba can produce hydrogen gas under anoxic conditions through an oxygen-sensitive hydrogenase located in its mitochondria, and they present AcMitoCarta as a framework for dissecting how aerobic and anaerobic energy metabolism interact.
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Filed underLegionella and Acanthamoeba research, Erythrocyte Function and Pathophysiology, Hemoglobin structure and function
