Cytosolic PRDX1 acts as an extramitochondrial sink to set mitochondrial H2O2 levels and enable resilience to chronic mitochondrial oxidative stress

accumulation. PRDX1 deficiency sensitized cells to chronic mitochondrial oxidative stress. A targeted CRISPR screen identified the Rab7 GAP TBC1D5, linking mitophagy to cellular survival under these conditions. Consistently, PRDX1/2-deficient cells exhibited elevated mitophagic flux, indicating mitochondrial quality control as a compensatory response. Our study reveals that cytosolic PRDXs critically impact mitochondrial redox homeostasis and provides a systems-level framework for understanding compartmental redox control and stress adaptation.