Table 1.

Redox potentials in resting cells at the beginning of experiments.

Cytosol	CF15-lacZ	CF15-CFTR	Hela
initial redox (mV)	−322	−320	−329
± SD	7	7	9
% oxidized	17.8	18.9	9.9
% reduced	82.2	81.1	90.1
Mitochondria	CF15-lacZ	CF15-CFTR	Hela
initial redox (mV)	−344	−345	−372
± SD	9	9	6
% oxidized	34.0	33.2	6.7
% reduced	66.0	66.8	93.3
Cell Surface	CF15-lacZ	CF15-CFTR	CF15
initial redox (mV)	−250	−250	−207 (a)
± SD	16	15	8
% oxidized	95.1	95.4
% reduced	4.9	4.6
ER	CF15-lacZ	CF15-CFTR	CF15
initial redox (mV)	−255	−256	−217 (a)
± SD	10	14	1
% oxidized	94.9	93.7
% reduced	5.1	6.3

(a) extrapolated potentials according to Fig. 5 roGFP1 fluorescence ratios were background-subtracted and normalized to minimal and maximal oxidation of the sensor. Ratios were converted to redox potentials using the in situ calibration described in Fig. 2B and values were then corrected for organelle pH.