PTEN and skin atrophy: Heterozygous deficiency of PTEN in the Sod2-deficient fibroblasts as achieved by crossing PTEN floxed mice with Col(I)α2-CreERT transgenic and Sod2 floxed mice (Col(I)α2CreERT+;Sod2f/f) followed by activation of CreERT with tamoxifen treatment (Supplementary Fig S8A and B) rescued skin atrophy/ageing in the double mutant mice (Col(I)α2-CreERT+;Sod2f/f;PTENf/+) compared with Sod2 mutant mice (Col(I)α2CreERT+;Sod2f/f;PTEN+/+) (Fig8A and B).