TRIM63 and sarcopenia: As compared with young mice (3 months old), aged mice (24 months old) showed thinner and bleaker hair (Fig. 1E), much heavier body weight (Fig. 1F), reduced fiber size of TA muscle (Fig. 1G), and increased atrophic gene (Atrogin1 and MuRF1) expression in TA muscle (Fig. 1, H and I), indicating the presence of sarcopenia in aged mice.