- Yan, Tianyang;
- Julio, Ashley R;
- Villanueva, Miranda;
- Jones, Anthony E;
- Ball, Andréa B;
- Boatner, Lisa M;
- Turmon, Alexandra C;
- Nguyễn, Kaitlyn B;
- Yen, Stephanie L;
- Desai, Heta S;
- Divakaruni, Ajit S;
- Backus, Keriann M
Proteinaceous cysteines function as essential sensors of cellular redox state. Consequently, defining the cysteine redoxome is a key challenge for functional proteomic studies. While proteome-wide inventories of cysteine oxidation state are readily achieved using established, widely adopted proteomic methods such as OxICAT, Biotin Switch, and SP3-Rox, these methods typically assay bulk proteomes and therefore fail to capture protein localization-dependent oxidative modifications. Here we establish the local cysteine capture (Cys-LoC) and local cysteine oxidation (Cys-LOx) methods, which together yield compartment-specific cysteine capture and quantitation of cysteine oxidation state. Benchmarking of the Cys-LoC method across a panel of subcellular compartments revealed more than 3,500 cysteines not previously captured by whole-cell proteomic analysis. Application of the Cys-LOx method to LPS-stimulated immortalized murine bone marrow-derived macrophages (iBMDM), revealed previously unidentified, mitochondrially localized cysteine oxidative modifications upon pro-inflammatory activation, including those associated with oxidative mitochondrial metabolism.