Fig. 6
From: TriPer, an optical probe tuned to the endoplasmic reticulum tracks changes in luminal H2O2
ER H2O2 increases in glutathione-depleted cells. a Bar diagram of fluorescence lifetime (FLT) of TriPerER expressed in the presence or absence of ER catalase (CAT ER) in RINm5F cells containing a tetracycline inducible pro-insulin gene. Where indicated pro-insulin expression was induced by doxycycline (DOX 20 ng/ml) and the cells were exposed to 0.3 mM BSO (18 h). b As in a, but TriPerER-expressing cells were exposed to 0.15 mM BSO (18 h). c A trace of time-dependent changes in HyPercyto or TriPerER FLT in RINm5F cells after exposure to 0.2 mM BSO. Each data point represents the mean ± SD of fluorescence lifetime measured in ≥20 cells. The ordinate of HyPercyto FLT was inverted to harmonize the trendlines of the two probes. d Bar diagram of FLT of ERroGFPiE, expressed in cells, untreated or exposed to 2 mM DTT, the oxidizing agent 2,2′-dipyridyl disulfide (DPS), or 0.3 mM BSO (18 h). e Bar diagram of FLT of an H2O2-unresponsive TriPer mutant (TriPerR266G) expressed in the ER of untreated or BSO-treated cells (0.3 mM; 18 h). f Bar diagram of FLT of TriPerER expressed in the presence or absence of ER catalase or an ER-localized glutathione-degrading enzyme (WT ChaC1 ER) or its enzymatically inactive E116Q mutant version (Mut ChaC1 ER). Shown are mean values ± SEM; *p < 0.05, **p < 0.01, ***p < 0.005, n ≥ 20)