RING finger, HC subclass, found in the transcriptional inknown asiary factor 1 (TIF1) family and similar proteins
This family corresponds to the TIF1 family of transcriptional cofactors including TIF1alpha (TRIM24), TIF1beta (TRIM28), and TIF1gamma (TRIM33), which belongs to the C-VI subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a plant homeodomain (PHD), and a bromodomain (Bromo) positioned C-terminal to the RBCC domain. TIF1 proteins couple chromatin modifications to transcriptional regulation, signaling, and tumor suppression. They exert a deacetylase-dependent silencing effect when tethered to a promoter region. TIF1alpha and TIF1beta can homodimerize and contain a PXVXL motif necessary and sufficient for heterochromatin protein 1(HP1) binding. They bind nuclear receptors and Kruppel-associated boxes (KRAB) specifically and respectively. TIF1gamma is structurally closely related to TIF1alpha and TIF1beta, but has very little functional features in common with them. It does not interact with the KRAB silencing domain of KOX1 or the heterochromatinic proteins HP1alpha, beta and gamma. It cannot bind to nuclear receptors (NRs). TIF1delta (TRIM66) doesn"t have RING-HC finger and is not included here.