RING finger, HC subclass, found in muscle-specific RING finger protein 3 (MuRF-3) and similar proteins
MuRF-3, also known as tripartite motif-containing protein 54 (TRIM54), or RING finger protein 30 (RNF30), is an E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover. It is ubiquitously detected in all fibre types, and is developmentally upregulated, associates with microtubules, the sarcomeric M-line (this report) and Z-line, and is required for microtubule stability and myogenesis. It associates with glutamylated microtubules during skeletal muscle development, and is required for skeletal myoblast differentiation and development of cellular microtubular networks. MuRF-3 controls the degradation of four-and-a-half LIM domain (FHL2) and gamma-filamin and is required for maintenance of ventricular integrity after myocardial infarction (MI). MuRF-3 belongs to the C-II subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.