Acts as a transcriptional corepressor in a IRF2-dependent manner, this repression is not mediated by histone deacetylase activities. Represses the NFAT1-dependent transactivation of NFAT-responsive promoters. Acts as a coactivator of VEGFA expression in cardiac and skeletal muscles. Plays a role in immature B-cell differentiation (By similarity). Interacts with IRF2. Part of a corepressor complex containing IRF2 and IRF2BP1. Interacts with VGLL4 (By similarity). The C-terminal RING-type zinc finger domain is sufficient for interaction with IRF2. Phosphorylation at Ser-343 is required for nuclear targeting. Belongs to the IRF2BP family.