MuRF1/TRIM63: Proteins and Enzymes

TRIM63 (Tripartite motif-containing protein 63; also MURF-1, SMRZ and RING finger protein 28) is a 41 kDa member of the RING finger-B-box-coiled-coil family of proteins. It is a striated muscle protein that is found in both cytoplasm and nucleus. TRIM63 has multiple finctions, among which are the inhibition of PKC epsilon-mediated cardiomyocyte hypertrophy and the maintenance of skeletal muscle M-line integrity. Human TRIM63 is 353 amino acids (aa) in length. It contains one RING finger domain (aa 23-82), a B-Box type zinc-finger region (aa 117-159), a coiled-coil region (aa 207-269) and a C-terminal COS domain. Isoforms of TRIM63 show one potential alternate start site at Met14, a deletion of aa 105-132 and a 21 aa substitution for aa 326-353. Over aa 1-325, human TRIM63 exhibits 93% aa identity with mouse TRIM63.