NEDD4 and Atrophy: Muscle atrophy was confirmed as evidenced by the decrease in gastrocnemius weight, gastrocnemius weight/body weight ratio, grip strength, myotube diameter (HE staining), mitochondria and glycogen content (periodic acid-schiff (PAS) and succinate dehydrogenase (SDH) stainings), MHC level and mtDNA copy numbers (Fig. 8b–e,j,k,m); and the increase in some atrogenes including Atrogin-1, Murf-1, Murf-2, Fbxo40, Traf6, Cblb and Nedd4 expressions, and protein ubiquitination and autophagy (Fig. 8h,i,l and Supplementary Fig. 7b,c).