FBXO32 and muscular atrophy: However, a recent integrated genomic and proteomic analysis of different types of murine skeletal muscle atrophy models by Hunt et al. showed that protein levels of atrogin-1 and MuRF-1 were not increased, and mRNA levels were only upregulated in glucocorticoid or cancer-induced muscle atrophy but not in atrophy caused by aging [194].