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

Basu, Somsurvo and Leonard, Joanne C. and Desai, Nishal and Mavridou, Despoina A. I. and Tang, Kong Ho and Goddard, Alan D. and Ginger, Michael and 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

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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 O(2), unexpectedly find O(2) and cytochrome c are reduced simultaneously, and demonstrate efficient reduction of O(2) by TbERV1 is not dependent upon a simple O(2) 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.

Item Type:
Journal Article
Journal or Publication Title:
Eukaryotic Cell
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2400/2404
Subjects:
ID Code:
61494
Deposited By:
Deposited On:
02 Jan 2013 11:15
Refereed?:
Yes
Published?:
Published
Last Modified:
29 Mar 2020 03:01