TRIM28, also known as transcriptional intermediary factor 1β (TIF1β) and KAP1, is a member of the tripartite motif family. This tripartite motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. TIF1-beta mediates transcriptional control by interaction with the Kruppel-associated box repression domain found in many transcription factors.