Oxidation of <i>Arabidopsis thaliana</i> COX19 Using the Combined Action of ERV1 and Glutathione

• Main Authors: Flavien Zannini (Author), Johannes M. Herrmann (Author), Jérémy Couturier (Author), Nicolas Rouhier (Author)
• Format: Book
• Published: MDPI AG, 2023-11-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antiox12111949; 2076-3921
• Keywords: MIA40; ERV1; glutathione; oxidative folding; mitochondrial intermembrane space; Therapeutics. Pharmacology; RM1-950
• Source: Antioxidants, Vol 12, Iss 11, p 1949 (2023)

Protein import and oxidative folding within the intermembrane space (IMS) of mitochondria relies on the MIA40-ERV1 couple. The MIA40 oxidoreductase usually performs substrate recognition and oxidation and is then regenerated by the FAD-dependent oxidase ERV1. In most eukaryotes, both proteins are essential; however, MIA40 is dispensable in <i>Arabidopsis thaliana</i>. Previous complementation experiments have studied yeast <i>mia40</i> mutants expressing a redox inactive, but import-competent versions of yeast Mia40 using <i>A. thaliana</i> ERV1 (AtERV1) suggest that AtERV1 catalyzes the oxidation of MIA40 substrates. We assessed the ability of both yeast and <i>Arabidopsis</i> MIA40 and ERV1 recombinant proteins to oxidize the apo-cytochrome reductase CCMH and the cytochrome <i>c</i> oxidase assembly protein COX19, a typical MIA40 substrate, in the presence or absence of glutathione, using in vitro cysteine alkylation and cytochrome <i>c</i> reduction assays. The presence of glutathione used at a physiological concentration and redox potential was sufficient to support the oxidation of COX19 by AtERV1, providing a likely explanation for why MIA40 is not essential for the import and oxidative folding of IMS-located proteins in <i>Arabidopsis</i>. The results point to fundamental biochemical differences between <i>Arabidopsis</i> and yeast ERV1 in catalyzing protein oxidation.