TIF1 alpha mediates transcriptional control by interaction with the activation function 2 (AF2) region of several nuclear receptors, including the estrogen, retinoic acid, and vitamin D3 receptors. The protein localizes to nuclear bodies and is thought to associate with chromatin and heterochromatin associated factors. The protein is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc binding domains (a RING, a B box type 1 and a B box type 2) and a coiled coil region.