MuRF1 (RNF28), MuRF2 (RNF29) and MuRF3 (RNF30) are a specific class of RING finger proteins expressed in striated muscle tissues that act as signaling molecules and cytoskeletal adaptors. The MuRF proteins contain a conserved N-terminal RING domain and zinc-binding B-box motif in addition to two coiled-coil motifs in their central regions. In muscle cells, MuRF2 regulates gene expression and protein turnover. It localizes to the cytoplasm, but under atrophic conditions it is detected in the nucleus. MuRF2 can form oligomers with various other proteins, including titin and myosin, during sarcomere assembly. Endogenous MuRF2 associates with the sarcomeric M-band in cardiomyocytes. There are at least four isoforms of MuRF2.