HLA-C and diabetes mellitus: To investigate the effect of celecoxib on the ubiquitin-proteasome system during diabetes-induced muscle atrophy, we identified the levels of Foxo3a, two E3 ubiquitin ligases (Fbx32 (also named Atrogin-1) and MuRF1) and myosin heavy chain (MHC) by western blotting.