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 D., 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://dx.doi.org/10.1128/EC.00304-12

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In yeast (Saccharomyces cerevisiae) 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 (TbERV1), 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 that 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 RNA interference (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. © 2013, American Society for Microbiology. All Rights Reserved.

Additional Information:Published ahead of print 21 December 2012
Keywords:cytochrome c, mitochondrial protein, oxidizing agent, oxidoreductase, oxygen, protozoal protein, thiol oxidase, amino acid substitution, article, chemistry, cytology, enzymology, gene silencing, genetics, kinetics, mitochondrion, mitochondrion swelling, molecular evolution, oxidation reduction reaction, phylogeny, protein folding, protein transport, RNA interference, site directed mutagenesis, Trypanosoma brucei, ultrastructure
Subjects:B Subjects allied to Medicine > B100 Anatomy, Physiology and Pathology
Divisions:College of Science > School of Life Sciences
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ID Code:11527
Deposited On:19 Sep 2013 10:10

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