TRIM63 and muscle atrophy: At the molecular level, skeletal muscle atrophy, whether due to disease or aging, is often associated with activation of the ubiquitin-proteasome system (UPS), including increased expression of muscle-specific E3 ubiquitin ligases such as MUSA1, MuRF-1, and Atrogin-1, as well as elevated levels of protein ubiquitination [26–29].