Complexome profiling of mitochondria in the myzozoan parasite of oysters, Perkinsus marinus.

Mitochondrial complexes, such as the mitochondrial electron transport chain (mETC), the F1Fo-ATP synthase, the mitochondrial ribosome and the Translocase of the Outer Membrane (TOM) complex are centrally important for mitochondrial function and cell survival. Recently, an unexpected diversity in the composition of these complexes across unicellular eukaryotic lineages, with the apicomplexan parasites featuring prominently, has been revealed. However, whether the observed enlarged and divergent mitochondrial complexes are conserved across the wider lineages has not been investigated. Here, using a complexome profiling proteomic approach, we have characterised the composition of the mitochondrial complexes of the myzozoan parasite of oysters, Perkinsus marinus. We show that it shares new components of ATP synthase and the mETC complexes that in the deadly apicomplexan Plasmodium and Toxoplasma were shown to be important for growth. Moreover, the Perkinsus mitoribosome possesses many of the divergent features recently discovered in apicomplexans, including members of the ApiAP2 family that until recently were all considered to be transcription factors. Our study reveals that the divergent subunit composition of mitochondrial complexes is an ancestral and highly conserved feature of Myzozoa.