A fluorescence resonance energy transfer (FRET)-based redox sensor reveals physiological role of thioredoxin in the yeast Saccharomyces cerevisiae

► Redoxfluor indicated reduced state in vitro by thioredoxin application. ► Starvation and mild-heat stresses caused oxidized cytoplasmic state of trx2 mutants. ► The oxidized state in the stress condition preceded viability loss of trx2 mutants.