Proteome-wide analysis of cysteine oxidation reveals metabolic sensitivity to redox stress, PART 1

Reactive oxygen species (ROS) are increasingly recognised as important regulators of cellular biology through the oxidative modification of protein cysteine residues. Comprehensive identification of redox-regulated proteins and cellular pathways are crucial to understand ROS-mediated events. Here, we present a new Stable Isotope Cysteine Labelling with IodoAcetamide (SICyLIA) MS-based proteomic workflow to assess protein cysteine oxidation in diverse cellular models and primary tissues. This approach informs on all possible cysteine oxidative modifications and achieves proteome-wide sensitivity with unprecedented depth without using enrichment steps. Our results suggest that acute and chronic oxidative stress cause metabolic adaptation through direct oxidation of metabolic and mitochondrial proteins. Analysis of chronically stressed fumarate hydratase-deficient mouse kidneys identified oxidation of proteins circulating in bio fluids, through which redox stress may affect whole-body physiology. Obtaining accurate peptide oxidation profiles from a complex organ using SICyLIA holds promise for future application to patient-derived samples in studies of human disease.