Thermal Proteome Profiling reveals rapid proteomic responses to redox changes in specific cellular compartments

Hydrogen peroxide (H ₂ O ₂ ) functions as a secondary messenger in cellular redox signaling, acting mainly via oxidation of protein thiols. Its spatially and temporally regulated activity within cells is essential for maintaining proper redox balance, and disruptions in these patterns can lead to oxidative stress and various related pathologies. Redox proteomics, which examines the impact of H ₂ O ₂ at the proteome level, typically focuses only on thiol oxidation, overlooking broader proteomic alterations and the significance of subcellular localization in these redox processes. In this study, we address these open questions by combining chemogenetics with Thermal Proteome Profiling (TPP) to map global proteome response to compartmentalized H ₂ O ₂ production. We identified hundreds of proteins with altered thermostability and/or abundance upon localized H ₂ O ₂ generation in the cytosol, nucleus, and the ER lumen, highlighting their roles in cellular responses to localized H ₂ O ₂ . We identified proteins such as MAP2K1, PARK7, TRAP1, and UBA2 to be highly sensitive to localized H ₂ O ₂ production. Furthermore, we validated their altered thermostability and found that these changes are controlled via dysregulated protein-protein interactions. This study provides a valuable resource for researchers exploring redox-mediated signal transduction and offers novel insights that could be harnessed in treating oxidative stress-induced pathologies.