FBXO32 and type 2 diabetes mellitus: However, focusing on the two most well-established muscle-specific E3 ubiquitin ligases, we only found a tendency for increased muscle expression of TRIM63 (encoding MuRF-1) in patients with T2D, whereas the expression of FBXO32 (encoding Atrogin-1) and its upstream regulator FOXO3 (encoding Forkhead-box protein O3) did not differ between the groups.