Phosphorylation of flotillin-1 by mitochondrial c-Src is required to prevent the production of reactive oxygen species

We have shown that mitochondrial c-Src regulates reactive oxygen species (ROS) production by phosphorylating the succinate dehydrogenase A of respiratory complex II (CxII). To elucidate the molecular mechanisms underlying ROS production regulated by c-Src in the CxII, we investigated the CxII protein complex derived from cells treated with Src family kinase inhibitor PP2. We identified flotillin-1 as a c-Src target that prevents ROS production from CxII. Phosphorylation-site analysis suggests Tyr56 and Tyr149 on flotillin-1 as sites for phosphorylation by c-Src. A comparison of cells expressing flotillin-1 and its phosphorylation defective mutants confirms the requirement for flotillin-1 phosphorylation for its interaction with CxII and subsequent reduction in ROS production. Our findings suggest a critical role of flotillin-1 in ROS production mediated by c-Src. Structured summary of protein interactions: SDHA, SDHB, SDHC, SDHD, flotillin-2 and flotillin-1, EMI5, TUFM, ANT2, ATP5A1, PHB, ATP5B, GRP75 and HSP60 physically interact by anti bait coip (View interaction) flotillin-1, cytochrome c and flotillin-2 colocalize by cosedimentation through density gradient (View interaction) (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.