Reversible oxidation of the RRM1 subunit of RNR in response to UVA-induced ROS.
MRC5Vi cells were untreated or exposed to UVA radiation in the absence (A) or presence (B) of 10 mM NaN3. (C) MRC5Vi cells were transiently transfected with siCtr, siTrx1, or siGrx1 and 48 h post transfection exposed or not to 80 kJ/m2 of UVA. (D) Cells depleted (+ BSO) or not (- BSO) in intracellular GSH were exposed to 80 kJ/m2 of UVA and lysed either immediately or 5 and 10 min post UVA radiation. The expressions of RRM1, RRM2, p53R2, Trx1, Grx1, and proteins S-glutathionylated (prot-SSG) were detected by Western blotting in non reducing (- ß-mercaptoethanol, - BME) or reducing (+ ß-mercaptoethanol, +BME) conditions. Actin was used as a loading control. RRM1ox and RRM1red stand for the oxidized and reduced form of the RRM1 subunit of the RNR, respectively. Each blot is representative of 2 independent experiments. The vertical lines in panels A and C denote non-adjacent bands from the same blot. Numbers in brackets (panel A) indicate the apparent molecular weight of each subunit.