GPX4 and kidney failure: In line with these results, a low residual GPX4 activity in Gpx4flox/cys;Rosa26_CreERT2 mice (exchange of the catalytic selenocysteine to cysteine on the residual allele) was sufficient to prevent spontaneous renal failure after tamoxifen application, whereas Gpx4flox/ser;Rosa26_CreERT2 mice (lacking residual activity) failed to prevent spontaneous tubular necrosis [72].