| 2005 |
MDM2 interacts with KAP1/TRIM28 via the N-terminal coiled-coil domain of KAP1 and the central acidic domain of MDM2; this interaction stimulates formation of a p53-HDAC1 complex, inhibits p53 acetylation, and promotes p53 ubiquitination and degradation. ARF competes with KAP1 for MDM2 binding, reducing KAP1-MDM2 interaction. |
Co-immunoprecipitation, RNAi knockdown, ubiquitination assay, competition binding assay |
The EMBO journal |
High |
16107876
|
| 2007 |
ATM-dependent phosphorylation of KAP1 at Ser-824 in response to genotoxic stress reduces KAP1 sumoylation, leading to de-repression of p21WAF1/CIP1 and Gadd45alpha. Conversely, a phospho-mimetic S824D mutation decreases sumoylation and stimulates p21 transcription, while S824A increases sumoylation and maintains repression. SENP1 deSUMOylase is involved in regulating basal KAP1 Ser-824 phosphorylation. |
Site-directed mutagenesis (S824A, S824D), ATM kinase assay, sumoylation assay, reporter gene assay, ChIP |
The Journal of biological chemistry |
High |
17942393
|
| 2008 |
The tandem PHD finger-bromodomain of KAP1 forms a unified structural scaffold in which the PHD finger and bromodomain cooperate as an intramolecular SUMO E3 ligase, facilitating lysine SUMOylation that is required for KAP1 co-repressor activity in gene silencing. Structure-function mutagenesis correlating UBC9 binding, SUMOylation, and transcriptional repression confirmed this. |
NMR solution structure determination, mutation-based structure-function analysis, SUMOylation assay, transcriptional repression assay, UBC9 binding assay |
Nature structural & molecular biology |
High |
18488044
|
| 2008 |
Phosphorylation of TIF1beta/KAP1 at Ser473 by PKCdelta disrupts its interaction with HP1beta (at the PXVXL HP1-box), reducing co-repressor function and permitting expression of cell cycle genes (cyclin A2, Cdc2, Cdc25A). Unphosphorylated KAP1 allows HP1beta co-occupancy at target promoters and transcriptional repression; Ser473 phosphorylation coincides with S-phase. |
Site-directed mutagenesis (S473A, S473E), ChIP, co-immunoprecipitation, reporter assays, PKCdelta inhibitor treatment |
BMC molecular biology |
High |
18590578
|
| 2011 |
KAP1 genomic recruitment requires its RBCC domain for binding to 3' coding exons of zinc finger genes (via KRAB-ZNF interaction), but RBCC deletion does not abolish KAP1 binding to promoter regions, indicating a second, KRAB-ZNF-independent recruitment mechanism for promoter-bound KAP1. |
ChIP-seq, stable cell lines expressing tagged wild-type and RBCC-deletion mutant KAP1, KAP1 knockdown |
Molecular and cellular biology |
High |
21343339
|
| 2013 |
De novo DNA methylation of endogenous retroviruses (ERVs) in embryonic stem cells requires a KRAB-ZFP that recognizes the specific ERV sequence, plus both KAP1 and ESET (SETDB1). KAP1 knockout in early embryos reduces methylation of ERVs. KAP1 thus acts downstream of KRAB-ZFPs and upstream of ESET to install stable DNA methylation marks at ERV loci. |
Genetic knockout (KAP1 KO in early embryos), reporter assay with introduced ERV sequences, bisulfite sequencing, ES cell differentiation model |
Development (Cambridge, England) |
High |
23293284
|
| 2014 |
TRIM28 stabilizes paused RNA Pol II at promoter-proximal regions of many genes and regulates Pol II pause release in a transcription-coupled phosphorylation-dependent manner. TRIM28 depletion triggers de novo expression of genes regulated by paused Pol II genome-wide. |
In vitro Pol II pausing assay, RNAi knockdown, genome-wide ChIP-seq of Pol II occupancy, gene expression analysis |
Nature structural & molecular biology |
High |
25173174
|
| 2015 |
The nuclear oncogene SET interacts with KAP1 and its overexpression causes sustained retention of KAP1 and HP1 on chromatin at double-strand breaks, leading to inhibition of DNA end resection and homologous recombination-mediated DNA repair. |
Co-immunoprecipitation, overexpression and depletion studies, chromatin fractionation, HR repair assay (I-SceI system) |
Cell reports |
Medium |
25818296
|
| 2016 |
URI (unconventional prefoldin RPB5 interactor) forms a nuclear complex with KAP1 and PP2A phosphatase; PP2A recruited by URI decreases KAP1 phosphorylation. This URI-KAP1-PP2A complex mediates retrotransposon (LINE-1, L1PA2) repression, functionally overlapping with the KAP1-SETDB1 silencing complex. |
Co-immunoprecipitation, mass spectrometry, URI knockdown, microarray of transposon expression, phosphorylation assay |
The Journal of biological chemistry |
Medium |
27780869
|
| 2017 |
TRIM28 forms a complex with EZH2 and SWI/SNF (distinct from PRC2) to activate, rather than repress, a set of stem cell maintenance genes in breast cancer cells. TRIM28 depletion represses EZH2 recruitment to chromatin and reduces mammosphere formation; rescue by EZH2 requires intact TRIM28 interaction (pre-SET domain). |
Co-immunoprecipitation, mass spectrometry, ChIP, siRNA knockdown, mammosphere formation assay, EZH2 mutant rescue experiment |
Oncogene |
High |
28068325
|
| 2018 |
TRIM28 acts as an E3 ubiquitin ligase for BCL2A1 at the mitochondria; endogenous TRIM28 and BCL2A1 physically interact and TRIM28 knockdown decreases BCL2A1 ubiquitination. TRIM17 antagonizes TRIM28 by blocking its binding to BCL2A1, stabilizing BCL2A1 and promoting chemoresistance. |
Co-immunoprecipitation, ubiquitination assay, TRIM28 knockdown, TRIM17 overexpression and knockout |
Cell death and differentiation |
High |
30042493
|
| 2018 |
TRIM28 physically interacts with TRIM24 and prevents TRIM24 ubiquitination and SPOP-mediated degradation; TRIM28 also facilitates TRIM24 chromatin occupancy and augments AR signaling in prostate cancer. |
Co-immunoprecipitation, ubiquitination assay, ChIP, knockdown and overexpression in cell lines and xenograft models |
Nature communications |
High |
30479348
|
| 2018 |
KAP1 associates with DNA replication factors PCNA, MCM3, and MCM6; these interactions are promoted by KAP1 phosphorylation at serine 473 during S phase. KAP1 forms a complex with PCNA and Suv39h1 histone methyltransferase to reinstate H3K9 methylation-dependent heterochromatin after DNA replication. |
Co-immunoprecipitation, phosphorylation-specific analysis (S473), ChIP, cell fractionation during S phase |
Nucleic acids research |
High |
29955894
|
| 2019 |
TRIM28 promotes HIV-1 latency by SUMOylating CDK9 (catalytic subunit of P-TEFb) at lysines K44, K56, and K68 with SUMO4. This SUMOylation inhibits CDK9 kinase activity and/or prevents P-TEFb assembly by blocking CDK9-Cyclin T1 interaction, thereby suppressing HIV-1 transcriptional elongation. |
Global site-specific SUMO-MS, serial SUMOylation assays, site-directed mutagenesis of CDK9 residues, Co-immunoprecipitation, kinase activity assay |
eLife |
High |
30652970
|
| 2019 |
The KAP1 TRIM domain forms antiparallel dimers that further assemble into tetramers and higher-order oligomers. Crystal structure identifies the KRAB domain binding site in the coiled-coil domain near the dimer dyad; mutations at this site abolish KRAB binding and retrotransposon silencing activity. B-box 1 mutations that prevent higher-order oligomerization do not significantly impair silencing. |
Crystal structure determination, biophysical analysis (SAXS, SEC-MALS), site-directed mutagenesis, retrotransposon silencing assay |
Proceedings of the National Academy of Sciences of the United States of America |
High |
31289231
|
| 2019 |
KAP1 is an elongated antiparallel dimer with functional asymmetry at the C-terminal domains. The RING domain contributes to KAP1 auto-SUMOylation. HP1 occupies only one of the two putative HP1 binding sites on the KAP1 dimer, resulting in an unexpected stoichiometry. |
Solution scattering (SAXS), integrative modeling, single-molecule experiments, biochemical assays |
Life science alliance |
High |
31427381
|
| 2020 |
KAP1/TRIM28 uses a chromatin reader cassette to bind hypo-acetylated histone H4 tails at promoters, then associates with RNA Pol II and recruits SMAD2 upon TGF-beta signaling to enable CDK9-dependent Pol II pause release. This couples chromatin reading to both Pol II pausing and pause release for transcriptional elongation. |
ChIP-seq, chromatin reader domain characterization, Co-immunoprecipitation, CDK9-dependent pause release assay, SMAD2 recruitment assay |
Molecular cell |
High |
32402252
|
| 2021 |
TRIM28 acts as an E3 SUMO ligase that binds NLRP3, promotes SUMO1/2/3 modification of NLRP3, and thereby inhibits NLRP3 ubiquitination and proteasomal degradation, stabilizing NLRP3 protein levels to facilitate inflammasome assembly and activation. Trim28 deficiency attenuates NLRP3 inflammasome activation in vitro and in vivo. |
Co-immunoprecipitation, SUMOylation assay, ubiquitination assay, Trim28 conditional knockout, NLRP3 inflammasome activation assays (IL-1β secretion, caspase-1 cleavage) |
Nature communications |
High |
34373456
|
| 2021 |
KAP1/TRIM28 represses HIV-1 expression in myeloid cells by interacting with and colocalizing with the viral transactivator Tat, promoting Tat's degradation via the proteasome. KAP1 is also bound to the latent HIV-1 promoter and cooperates with CTIP2, an epigenetic silencer; Tat and CTIP2 compete for KAP1 binding. |
Co-immunoprecipitation, colocalization (confocal microscopy), proteasome inhibitor treatment, KAP1 depletion, ChIP, myeloid HIV-1 latency model reactivation |
Scientific reports |
Medium |
33514850
|
| 2021 |
UBE2S interacts with TRIM28 in the nucleus; together they enhance ubiquitination of p27 to facilitate its proteasomal degradation and promote G1/S cell cycle progression in hepatocellular carcinoma cells. |
Co-immunoprecipitation, ubiquitination assay, cell cycle analysis, siRNA knockdown |
Signal transduction and targeted therapy |
Medium |
33589597
|
| 2021 |
The SETDB1-TRIM28 complex suppresses antitumor immunity; inhibition of this complex upregulates PD-L1 and activates the cGAS-STING innate immune pathway by promoting micronuclei formation in the cytoplasm, increasing CD8+ T cell infiltration. |
CRISPR-Cas9 epigenetic screen, flow cytometry, cGAS-STING pathway activation assay, syngeneic mouse tumor model, SETDB1 KO |
Cancer immunology research |
Medium |
34848497
|
| 2021 |
TRIM28 acts as a negative regulator of aggresome formation through direct interaction with CTIF; this interaction leads to inefficient aggresomal targeting of misfolded polypeptides. TRIM28 phosphorylation at S473 by double-stranded RNA-activated protein kinase (PKR) promotes TRIM28-CTIF association, inhibits aggresome formation, and suppresses viral proliferation. |
Co-immunoprecipitation, proximity ligation assay, phosphorylation analysis (S473), aggresome formation assay, influenza A virus infection model |
Autophagy |
High |
33783327
|
| 2021 |
TRIM28 is a transcriptional activator of the mutant TERT promoter. TRIM28 is recruited to the mutant hTERT promoter and interacts with TRIM24, which inhibits TRIM28 activity. Phosphorylation of TRIM28 via mTORC1 releases it from TRIM24 and induces hTERT transcription; mTORC1 inhibition suppresses TRIM28 phosphorylation and hTERT expression. |
CRISPR-Cas9 kinome knockout screen (FACS-based), ChIP, Co-immunoprecipitation, mTORC1 inhibition (rapamycin analog), phosphorylation assays |
Proceedings of the National Academy of Sciences of the United States of America |
High |
34518220
|
| 2022 |
Crystal structure of the KAP1 TRIM in complex with the KRAB domain of ZNF93 identifies the KAP1-KRAB binding interface. Structure-guided mutations in this interface abolish repressive activity in a transcriptional silencing assay and eliminate genome-wide H3K9me3 deposition at thousands of KAP1/KRAB-ZFP target loci. |
Crystal structure determination, site-directed mutagenesis, epigenetic transcriptional silencing assay, ChIP-seq (H3K9me3 genome-wide) |
The EMBO journal |
High |
36341546
|
| 2022 |
TRIM28-dependent SUMOylation is required to maintain the adult ovarian cell fate by repressing testicular-specific genes. TRIM28 is recruited to chromatin near FOXL2 binding sites, and its E3-SUMO ligase activity regulates the sex-specific SUMOylation profile of ovarian-specific genes. Loss of Trim28 in granulosa cells leads to their transdifferentiation into Sertoli cells. |
Conditional knockout (Trim28 deletion in granulosa cells), ChIP, SUMOylation profiling, histology/lineage tracing |
Nature communications |
High |
35906245
|
| 2022 |
KAP1 and the KRAB domain residues forming the molecular interface were structurally mapped using AlphaFold2; leucine 301 on each chain of the TRIM28 coiled-coil acts as a 'pin' inserting into a hydrophobic pocket on the KRAB domain. Site-directed mutations at this interface abolish KRAB domain binding. |
AlphaFold2 modeling, site-directed mutagenesis, binding assays |
Protein science |
Medium |
36173157
|
| 2023 |
TRIM28 directly binds and stabilizes PD-L1 by inhibiting PD-L1 ubiquitination and promoting PD-L1 SUMOylation. Additionally, TRIM28 facilitates K63 polyubiquitination of TBK1, activating TBK1-IRF1 and TBK1-mTOR pathways to enhance PD-L1 transcription. |
CRISPR-Cas9 genome-wide screen, Co-immunoprecipitation, ubiquitination assay, SUMOylation assay, in vivo mouse tumor model, TBK1 pathway inhibitor studies |
Signal transduction and targeted therapy |
High |
37357254
|
| 2023 |
TRIM28 promotes ubiquitination and proteasome-mediated degradation of TFE3 transcription factor in renal cancer cells, thereby suppressing TFE3-driven autophagic gene expression and cell proliferation. This defines a TRIM28-TFE3-KDM6A signaling axis in kidney cancer. |
Co-immunoprecipitation, ubiquitination assay, TRIM28 knockdown, ChIP, autophagy assays, cell proliferation assays |
The Journal of biological chemistry |
Medium |
36935008
|
| 2023 |
TRIM28 physically interacts with RIPK1 and promotes K63-linked ubiquitination of RIPK1, sustaining NF-κB pathway activation and upregulation of CXCL1, which recruits MDSCs. Mutagenesis of the TRIM28 RING/E3 ligase domain (C65, C68) abrogates NF-κB activation. |
Co-immunoprecipitation, K63-ubiquitination assay, RING domain mutagenesis, NF-κB reporter, CXCL1 ELISA, syngeneic mouse tumor models |
Journal of experimental & clinical cancer research |
High |
37865804
|
| 2023 |
TRIM28 acts as the E3 SUMO ligase responsible for SUMOylation of the SARS-CoV-2 nucleocapsid protein (SARS2-NP) at lysine K65, which mediates NP homo-oligomerization, RNA association, liquid-liquid phase separation, and suppression of innate antiviral immunity. An interfering peptide targeting the TRIM28-SARS2-NP interaction blocks NP SUMOylation and LLPS. |
SUMOylation assay, site-directed mutagenesis (K65), LLPS assay, Co-immunoprecipitation, antiviral immune assay, interfering peptide screen |
Nature communications |
High |
38172120
|
| 2023 |
TRIM28 negatively regulates the RLR signaling pathway by targeting MAVS for K48-linked polyubiquitination and proteasome-mediated degradation. The RING domain of TRIM28 (specifically C65 and C68 residues) is critical for this activity; ubiquitin chains are transferred to K7, K10, K371, K420, and K500 of MAVS. |
Ubiquitination assay, proteasome inhibitor treatment, RING domain mutagenesis, Co-immunoprecipitation, type I interferon production assay |
The Journal of biological chemistry |
High |
37119745
|
| 2023 |
TIAM1 interacts with TRIM28 in the nucleus of NSCLC cells and the TIAM1-TRIM28 complex promotes H3K9me3-induced silencing of protocadherins and decreases E-cadherin expression, driving epithelial-to-mesenchymal transition and cell migration. |
Co-immunoprecipitation, ChIP (H3K9me3), siRNA knockdown, migration/invasion assay, rescue by protocadherin depletion |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
37748077
|
| 2023 |
TRIM28 binds ACSL4 and promotes SUMO3 modification at ACSL4 lysine K532, inhibiting K63-linked ACSL4 ubiquitination and thereby suppressing OPTN-dependent autophagic degradation of ACSL4, promoting neuronal ferroptosis. SENP3 acts as the opposing deSUMOylation enzyme. |
Co-immunoprecipitation, SUMOylation assay, ubiquitination assay, mutagenesis (K532), autophagic degradation assay, Trim28 genetic deletion, in vivo SCI mouse model |
Cell death and differentiation |
High |
39875520
|
| 2024 |
TRIM28 facilitates type I interferon activation by interacting with TBK1 and mediating K63-linked ubiquitination of TBK1, augmenting TBK1 signal transmission; TRIM28 KO cells display defective TBK1 phosphorylation and impaired complex assembly with IRF3. |
CRISPR-Cas9 TRIM28 knockout, Co-immunoprecipitation, K63-ubiquitination assay, TBK1 phosphorylation assay, virus infection susceptibility assay |
Frontiers in immunology |
Medium |
38495890
|
| 2024 |
TRIM28 acts as an E3 ubiquitin ligase for BRD7; the coiled-coil region of TRIM28 binds the N-terminal domain of BRD7 and mediates BRD7 ubiquitination at K21, promoting its proteasomal degradation. This promotes breast cancer malignant progression. |
Co-immunoprecipitation with mass spectrometry, ubiquitination assay, domain deletion/mutagenesis (K21), xenograft mouse model |
Cellular oncology (Dordrecht, Netherlands) |
High |
39222175
|
| 2012 |
KAP1 directly interacts with IRF5 via IRF5's N-terminus (DNA-binding domain and disordered region); KAP1 knockdown potentiates IRF5-mediated TNF and M1 macrophage marker expression. This inhibitory effect is linked to SETDB1 methyltransferase activity (H3K9me3 deposition) at the TNF locus. |
Affinity purification with mass spectrometry (IRF5 interactome), Co-immunoprecipitation, domain mapping, KAP1 siRNA knockdown, ChIP (H3K9me3) |
Immunobiology |
Medium |
22995936
|
| 2007 |
KAP1 physically associates with endogenous STAT3 in cells; KAP1 knockdown enhances IL-6-induced STAT3-dependent transcription and causes marked accumulation of STAT3 phosphorylated on Ser727 in the nucleus, indicating KAP1 acts as a transcriptional repressor of the IL-6/STAT3 signaling pathway. |
Yeast two-hybrid screen, endogenous Co-immunoprecipitation, siRNA knockdown, reporter gene assay, phospho-STAT3 analysis |
Oncogene |
Medium |
18037959
|
| 2020 |
Kap1 interacts with Oct4 and inhibits Itch-mediated ubiquitination of Oct4 at lysine K133, thereby stabilizing Oct4 protein in embryonic stem cells and promoting self-renewal and cellular reprogramming. |
Affinity purification with mass spectrometry, Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis (K133R), Kap1 knockdown and overexpression, reprogramming assay |
Cell death and differentiation |
High |
32895487
|
| 2012 |
KAP1-dependent H3K9me3 repressive chromatin is established at T-cell-specific cis-regulatory elements enriched in Ikaros/NuRD complexes; KAP1 directly controls FoxO1 expression and TCR/cytokine signaling genes. T-cell-specific Kap1 deletion causes expansion of immature thymocytes and altered CD4+/CD8+ ratios. |
T-cell-specific conditional Kap1 KO (Cre-lox), ChIP/ChIP-seq, transcriptome analysis |
FASEB journal |
Medium |
22872677
|
| 2023 |
TRIM28 modulates uterine function by complexing with estrogen receptor α (ERα) and progesterone receptor (PR); TRIM28 ablation suppresses PR and ERα chromatin binding in uterine epithelium and stroma, impairing implantation and early pregnancy. |
RIME (rapid immunoprecipitation mass spectrometry), Co-immunoprecipitation, conditional knockout, ChIP |
Nature communications |
High |
37528140
|
| 2012 |
MAGE-C2 binds KAP1 and increases co-precipitation of KAP1 with ATM kinase; MAGE-C2 binding to KAP1 is required for enhanced ATM-dependent phosphorylation of KAP1-Ser824, which facilitates heterochromatin relaxation and DNA double-strand break repair. |
Co-immunoprecipitation, KAP1 S824 phosphorylation assay, I-SceI endonuclease DSB repair assay, MAGE-C2 knockdown/overexpression |
The Journal of investigative dermatology |
Medium |
23096706
|
| 2015 |
CCAR2/DBC1 is required for Chk2-dependent KAP1 phosphorylation at Ser824; loss of CCAR2 impairs Chk2 activation and reduces KAP1 S824 phosphorylation, leading to defective heterochromatin relaxation and impaired repair of heterochromatic DSBs. |
CCAR2 knockout, Chk2 activation assay, KAP1 S824 phosphorylation assay, DNA damage foci resolution (late time-point), HP1β depletion rescue |
Oncotarget |
Medium |
26158765
|
| 2022 |
At the onset of X chromosome inactivation, KAP1 is recruited to the Xist promoter allele that will upregulate Xist and is required for the increase in Tsix levels preceding cell fate choice. RIF1 and KAP1 show mutual exclusion at the Xist promoters, establishing an asymmetric self-sustaining loop for X chromosome choice. |
mESC differentiation, allele-specific ChIP, KAP1 and RIF1 depletion, Tsix/Xist RNA FISH |
The EMBO journal |
Medium |
34786738
|
| 2018 |
KAP1 interacts with KAP1 regulates ERV (including HERV-T, HERV-S) and ZNF gene expression in adult differentiated human cells including peripheral blood mononuclear cells, requiring H3K9me3. KAP1 depletion leads to decreased H3K9me3 at ERVs and ZNF loci and activates an RNA-sensing response mediated through MAVS signaling. |
KAP1 knockout, RNA-seq, ChIP-seq (H3K9me3, KAP1), MAVS signaling assay, interferon response measurement |
EMBO reports |
Medium |
30061100
|