Transcription intermediary factor 1-beta - Q13263 (TIF1B_HUMAN)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for Q13263: 3
 
Function
Nuclear corepressor for KRAB domain-containing zinc finger proteins (KRAB-ZFPs). Mediates gene silencing by recruiting CHD3, a subunit of the nucleosome remodeling and deacetylation (NuRD) complex, and SETDB1 (which specifically methylates histone H3 at 'Lys-9' (H3K9me)) to the promoter regions of KRAB target genes. Enhances transcriptional repression by coordinating the increase in H3K9me, the decrease in histone H3 'Lys-9 and 'Lys-14' acetylation (H3K9ac and H3K14ac, respectively) and the disposition of HP1 proteins to silence gene expression. Recruitment of SETDB1 induces heterochromatinization. May play a role as a coactivator for CEBPB and NR3C1 in the transcriptional activation of ORM1. Also corepressor for ERBB4. Inhibits E2F1 activity by stimulating E2F1-HDAC1 complex formation and inhibiting E2F1 acetylation. May serve as a partial backup to prevent E2F1-mediated apoptosis in the absence of RB1. Important regulator of CDKN1A/p21(CIP1). Has E3 SUMO-protein ligase activity toward itself via its PHD-type zinc finger. Also specifically sumoylates IRF7, thereby inhibiting its transactivation activity. Ubiquitinates p53/TP53 leading to its proteosomal degradation; the function is enhanced by MAGEC2 and MAGEA2, and possibly MAGEA3 and MAGEA6. Mediates the nuclear localization of KOX1, ZNF268 and ZNF300 transcription factors. In association with isoform 2 of ZFP90, is required for the transcriptional repressor activity of FOXP3 and the suppressive function of regulatory T-cells (Treg) (PubMed:23543754). Probably forms a corepressor complex required for activated KRAS-mediated promoter hypermethylation and transcriptional silencing of tumor suppressor genes (TSGs) or other tumor-related genes in colorectal cancer (CRC) cells (PubMed:24623306). Also required to maintain a transcriptionally repressive state of genes in undifferentiated embryonic stem cells (ESCs) (PubMed:24623306). Associates at promoter regions of tumor suppressor genes (TSGs) leading to their gene silencing (PubMed:24623306). The SETDB1-TRIM28-ZNF274 complex may play a role in recruiting ATRX to the 3'-exons of zinc-finger coding genes with atypical chromatin signatures to establish or maintain/protect H3K9me3 at these transcriptionally active regions (PubMed:27029610). Acts as a corepressor for ZFP568. UniProt
Catalytic Activity
S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N6-ubiquitinyl-[acceptor protein]-L-lysine. UniProt
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Subunit Structure
Interacts with SETX (PubMed:23149945). Oligomer; the RBCC domain homotrimerizes and interacts with one molecule of KRAB to form the KRAB-KAP1 corepressor complex. Binding to a KRAB domain is an absolute requirement for silencing gene expression. Interacts with CEBPB and NR3C1. Interacts with a number of KRAB-ZFP proteins including ZNF10, ZFP53, ZFP68, ZNF382 and ZNF256. Interacts with NCOR1, NR3C1 and CHD3. Interacts with CEBPB (via the RING-type and PHD-type zinc fingers). Component of a ternary complex that includes TRIM28, a HP1 protein (CBX1, CBX3 OR CBX5), a KRAB domain-containing protein, and DNA. Interacts with CBX5 (via the PxVxL motif); the interaction occurs in interphase nuclei and competes for binding POGZ. Interacts with POGZ; the interaction competes for interaction with CBX5. Interacts with SETDB1; the interaction is enhanced by KAP1 sumoylation, stimulates SETB1 histone methyltransferase activity and gene silencing. Interacts (via the PHD-type zinc finger) with UBE2I; the interaction is required for sumoylation and repressor activity. Component of the TRIM28/KAP1-ERBB4-MDM2 complex involved in connecting growth factor and DNA damage responses. Interacts directly with ERBB4; the interaction represses ERBB4-mediated transcription activity. Interacts with MDM2; the interaction contributes to p53/TP53 inactivation. Component of the TRIM28/KAP1-MDM2-p53/TP53; involved in regulating p53/TP53 stabilization and activity. Interacts (via the leucine zipper alpha helical coiled-coil) with E2F1 (central region); the interaction inhibits E2F1 acetylation and transcriptional activity. Interacts with PPP1CA; the interaction dephosphorylates TRIM28 at Ser-824 and forms a complex at the p21 promoter site. Interacts with PPP1CB; the interaction is weak but is increased on dephosphorylation at Ser-824. Interacts with FES/FPS. Interacts with SMARCAD1. Interacts with, and sumoylates IRF7. Interacts with MAGEC2. Part of a complex composed of TRIM28, HDAC1, HDAC2 and EHMT2. Interacts with AICDA (By similarity). Interacts (via the RBCC domain) with KOX1 (via the KRAB domain), ZNF268 (via the KRAB domain) and ZNF300 (via the KRAB domain); the interactions increase KOX1, ZNF268 and ZNF300 nuclear localization activities. The large PER complex involved in the histone methylation is composed of at least PER2, CBX3, TRIM28, SUV39H1 and/or SUV39H2; CBX3 mediates the formation of the complex. Interacts with isoform 2 of ZFP90. Forms a complex with FOXP3 in the presence of isoform 2 of ZFP90. Interacts with NR4A3; the interactions potentiates NR4A3 activity on NurRE promoter (By similarity). Interacts (unphosphorylated or phosphorylated form) with ZBTB1 (via BTB domain) (PubMed:24657165). Probably part of a corepressor complex containing ZNF304, TRIM28, SETDB1 and DNMT1 (PubMed:24623306). Interacts with ATRX. Forms a complex with ATRX, SETDB1 and ZNF274 (PubMed:27029610). Interacts with ZFP568; the interaction mediates ZFP568 transcriptional repression activity (By similarity). Interacts with RRP1B (PubMed:19710015). UniProt
Domain
Contains one Pro-Xaa-Val-Xaa-Leu (PxVxL) motif, which is required for interaction with chromoshadow domains. This motif requires additional residues -7, -6, +4 and +5 of the central Val which contact the chromoshadow domain. UniProt
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