Divergence of Erv1-associated mitochondrial import and export pathways in trypanosomes and anaerobic protists

Basu, Somsuvro, Leonard, Joanne C., Desai, Nishal , Mavridou, Despoina A. I., Tang, Kong Ho, Goddard, Alan, Ginger, Michael L., Lukes, Julius and Allen, James W. A. (2013) Divergence of Erv1-associated mitochondrial import and export pathways in trypanosomes and anaerobic protists. Eukaryotic Cell, 12 (2). pp. 343-355. ISSN 1535-9778

Full content URL: http://ec.asm.org/content/12/2/343

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Item Type:Article
Item Status:Live Archive

Abstract

In yeast and animals, the sulfhydryl oxidase Erv1 functions with Mia40 in the import and oxidative folding of numerous cysteine-rich proteins in the mitochondrial intermembrane space (IMS). Erv1 is also required for Fe-S cluster assembly in the cytosol which uses at least one mitochondrially derived precursor. Here, we characterize an essential Erv1 orthologue from the protist Trypanosoma brucei, which naturally lacks a Mia40 homolog. We report kinetic parameters for physiologically relevant oxidants cytochrome c and O2, unexpectedly find O2 and cytochrome c are reduced simultaneously, and demonstrate efficient reduction of O2 by TbERV1 is not dependent upon a simple O2 channel defined by conserved histidine and tyrosine residues. Massive mitochondrial swelling following TbERV1 RNAi provides evidence that trypanosome Erv1 functions in IMS protein import despite the natural absence of the key player in the yeast and animal import pathways, Mia40. This suggests significant evolutionary divergence from a recently established paradigm in mitochondrial cell biology. Phylogenomic profiling of genes also points to a conserved role for TbERV1 in cytosolic Fe-S cluster assembly. Conversely, loss of genes implicated in precursor delivery for cytosolic Fe-S assembly in Entamoeba, Trichomonas, and Giardia suggests fundamental differences in intracellular trafficking pathways for activated iron or sulfur species in anaerobic versus aerobic eukaryotes.

Keywords:Erv1
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
Divisions:College of Science > School of Life Sciences
ID Code:7176
Deposited On:04 Jan 2013 14:47

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