TRIM63 and chronic obstructive pulmonary disease: Skeletal muscle of COPD patients has been reported to express elevated levels of MuRF‐1 and MAFbx, and reductions in mTORC1 signaling proteins such as p70S6 kinase and 4EBP‐1 [Favier et al., 2010], and thus both reductions in protein synthesis and increases in protein breakdown likely drive the loss of muscle size in this disease state.