Fig. 4

TRIM28 is recruited to the genome by KRAB-ZNF transcription factors to facilitate chromatin compaction-mediated gene repression. a TRIM28 binds to KRAB domain of KRAB-ZNF proteins tethered to specific sequences within the genome using N-terminal RING-B-boxes-Coiled-Coil (RBCC) domain and catalyzes auto-SUMOylation of Bromodomain (utilizing Ubc9 as an E2 SUMO ligase). b SUMOylated TRIM28 recruits SETDB1 and NuRD complex proteins leading to the creation of the H3K9me3 mark on nearby nucleosomes together with deacetylation of histone proteins. HP1 binding further stabilizes the TRIM28-containing complex bound to the KRAB-ZNF