TIF1-α was cloned as the prototypical member of the TIF1 family of corepressors, characterized by possession of a RBCC motif and a C-terminal bromodomain preceded by a PHD finger, in addition to binding sites for the KRAB silencing domains of C2H2 zinc finger domains. The TIF1-gene product was independently characterized as the powerfull coactivator CARM1 C-terminal coactivator partner (CCCP), which binds to the C-terminal region of CARM1 and cooperates synergistically with CARM1 to enhance NR function.