Reversible oxidation of the RRM1 subunit of RNR in response to UVA-induced ROS.

<p>MRC5Vi cells were untreated or exposed to UVA radiation in the absence (<b>A</b>) or presence (<b>B</b>) of 10 mM NaN₃. (<b>C</b>) MRC5Vi cells were transiently transfected with siCtr, siTrx1, or siGrx1 and 48 h post transfection exposed or not to 80 kJ/m² of UVA. (<b>D</b>) 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. RRM1^ox and RRM1^red 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.