Ndufaf2, a protein in mitochondrial complex I, interacts in vivo with methionine sulfoxide reductases

• Published in: Redox report : communications in free radical research 2023-12, Vol.28 (1), p.2168635-2168635
• Main Authors: Park, Sujin, Trujillo-Hernandez, José A., Levine, Rodney L.
• Format: Article
• Language: English
• Subjects: HEK293 Cells; Humans; mass spectrometry; Methionine - metabolism; methionine oxidation; Methionine sulfoxide reductase; Methionine Sulfoxide Reductases - metabolism; mimitin; mitochondrial complex I; Mitochondrial Proteins - metabolism; Molecular Chaperones - metabolism; Ndufaf2; Oxidative Stress; Proteomics; TurboID proximity labeling
• ISSN: 1351-0002; 1743-2928
• DOI: 10.1080/13510002.2023.2168635

Methionine sulfoxide reductases are found in all aerobic organisms. They function in antioxidant defense, cellular regulation by reversible oxidation of methionine in proteins, and in protein structure. However, very few in vivo binding partners or substrates of the reductases have been identified. We implemented a proximity labeling method, TurboID, to covalently link mitochondrial methionine sulfoxide reductase A (MSRA) to its binding partners in HEK293 cells. Proteomic analyses were performed to identify putative binding partners. We show that human Ndufaf2, also called mimitin, is a binding partner of MSRA as well as all 3 MSRBs. We found that both methionine residues in Ndufaf2 were susceptible to oxidation by hydrogen peroxide and that the methionine sulfoxide reductases can reduce these methionine sulfoxide residues back to methionine. Methionine sulfoxide reductases can reduce methionine sulfoxide back to methionine in Ndufaf2. In addition to a repair function, it also creates a mechanism that could regulate cellular processes by modulation of methionine oxidation in Ndufaf2.