E3 ubiquitin ligase that plays an important role in regulating cardiac development and contractility, muscle growth, metabolism, and fiber-type differentiation. Acts as a critical factor that regulates cardiomyocyte size during development in concert with TRIM63 by regulating E2F1-mediated gene expression. Plays a role in apoptosis induction in cardiomyocytes by promoting ubiquitination of the DUSP1 phosphatase. Promotes non-canonical NF-kappa-B signaling and B-cell-mediated immune responses by mediating NFKB2 'Lys-48'-linked ubiquitination and processing. In turn, NFKB2 is further processed by valosin-containing protein/VCP, an ATPase that mediates ubiquitin-dependent protein degradation by the proteasome. May play a role in preventing macrophages from producing inflammatory factors and migrating by downregulating the level of nuclear NF-kappa-B subunit RELA. Modifies also PPARG via polyubiquitination and accelerates PPARG proteasomal degradation to inhibit its activity.