| 1997 |
SMRT/NCOR2 directly interacts with mSin3A, which in turn interacts with HDAC1, forming a multisubunit repressor complex that mediates transcriptional repression by nuclear receptors (thyroid hormone and retinoic acid receptors). |
Co-immunoprecipitation, protein interaction assays, functional reporter assays with HDAC inhibitors |
Cell |
High |
9150137
|
| 2000 |
SMRT and N-CoR exist in large (~1.5–2 MDa) protein complexes in HeLa nuclear extracts containing HDAC3 and TBL1 (a WD-40 repeat protein); these complexes bind unliganded thyroid hormone receptors in vitro, and antibodies against HDAC3 or SMRT/N-CoR partially relieve TR/RXR-mediated repression in Xenopus oocytes. |
Conventional and immunoaffinity chromatography, co-immunoprecipitation, in vitro binding assay, antibody microinjection in Xenopus oocytes |
The EMBO journal |
High |
10944117
|
| 2000 |
SMRT forms a core complex with HDAC3 and TBL1; TBL1 interacts with histone H3 and is bridged to HDAC3 through SMRT, and TBL1 can potentiate transcriptional repression by thyroid hormone receptor in vivo. |
Immunoaffinity purification of HeLa nuclear extract SMRT complex, co-immunoprecipitation, histone interaction assays, transcriptional reporter assays |
Genes & development |
High |
10809664
|
| 2001 |
SMRT functions as an activating cofactor for HDAC3 via a deacetylase activating domain (DAD) that includes one of its two SANT motifs. Recombinant HDAC3 alone is enzymatically inactive; SMRT DAD is necessary and sufficient to reconstitute HDAC3 deacetylase activity using purified components. Mutations in the DAD that abolish HDAC3 interaction also eliminate HDAC activity and the major repression function of SMRT. |
In vitro reconstitution with purified components, HDAC activity assays, mutagenesis of DAD domain, stable complex isolation |
Molecular and cellular biology |
High |
11509652
|
| 1997 |
SMRT contains two distinct receptor interaction domains that independently bind nuclear receptors, and two separate transcriptional repression domains. Both repression domains interact weakly with mSin3A, and SMRT overexpression represses transcription from natural promoters. |
Deletion analysis, mammalian two-hybrid, Far-Western, co-immunoprecipitation, transcriptional reporter assays |
Molecular endocrinology |
High |
9415406
|
| 1996 |
SMRT is a ubiquitous nuclear protein that interacts with unliganded nuclear receptor heterodimers in mammalian cells; expression of the receptor-interacting domain of SMRT acts as an antirepressor, and splicing variants modulate thyroid hormone and retinoic acid signaling. |
Mammalian cell transfection, co-immunoprecipitation, transcriptional reporter assays |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
8755515
|
| 1998 |
SMRT interacts with the BCL-6 POZ/BTB domain, and this interaction is necessary for BCL-6-mediated transcriptional repression; POZ domains from other repressors (PLZF, ZID, GAGA) also interact with SMRT/N-CoR in vitro; BCL-6 and N-CoR co-localize to punctate nuclear regions. |
Yeast two-hybrid, mammalian two-hybrid, GST pulldown, co-immunoprecipitation, immunofluorescence co-localization, transcriptional reporter assays |
Oncogene |
High |
9824158
|
| 2003 |
Crystal structure (2.2 Å) of the BCL6 BTB homodimer bound to a 17-residue SMRT fragment: two SMRT peptides bind symmetrically to the BCL6 BTB homodimer, revealing the structural basis of SMRT recruitment for transcriptional repression. |
X-ray crystallography, biochemical binding assays, in vivo functional assays |
Molecular cell |
High |
14690607
|
| 2000 |
SMRT function is inhibited by a MAPK kinase kinase cascade downstream of EGF receptor: SMRT is phosphorylated by MEKK-1 and MEK-1, which inhibits its ability to tether to transcription factor partners and causes redistribution from nucleus to a perinuclear/cytoplasmic compartment. |
Kinase assays, transfection with constitutively active kinase constructs, subcellular fractionation, co-immunoprecipitation, transcriptional reporter assays |
Molecular and cellular biology |
High |
10938135
|
| 2004 |
IKKα phosphorylates SMRT on chromatin, triggering nuclear export of SMRT and loss of chromatin-associated HDAC3, which is prerequisite for NF-κB-dependent transcription of cIAP-2 and IL-8; a nonphosphorylatable SMRT mutant blocks NF-κB recruitment and sensitizes cells to apoptosis. |
Chromatin immunoprecipitation (ChIP), nonphosphorylatable SMRT mutant expression, nuclear export assays, transcriptional reporter assays |
Molecular cell |
High |
15494311
|
| 2006 |
IKKα phosphorylates both SMRT(S2410) and RelA/p65(S536) on chromatin; phospho-SMRT remains bound to NF-κB heterodimer but loses HDAC3 association, enabling p300-mediated acetylation of RelA/p65 at K310; nonphosphorylatable SMRT or RelA mutants maintain active SMRT-HDAC3 repression. |
ChIP, re-ChIP, nonphosphorylatable mutant expression, transcriptional reporter assays |
Molecular and cellular biology |
High |
16382138
|
| 2001 |
SMRTe (full-length SMRT) inhibits MEF2C transcriptional activation by translocating HDAC4 from the cytoplasm to discrete nuclear domains and recruiting HDAC5 into these domains; SMRTe synergizes with HDAC4 and HDAC5 to inhibit MEF2C-dependent muscle differentiation gene expression. |
Indirect immunofluorescence, co-immunoprecipitation, nuclear fractionation, transcriptional reporter assays |
The Journal of biological chemistry |
Medium |
11304536
|
| 2001 |
SMRT binds to the N-terminal coiled-coil domain of STAT5A and STAT5B, strongly represses STAT5-dependent transcription; a hyperactivating mutation in the STAT5 coiled-coil domain that renders it constitutively active abolishes SMRT interaction; SMRT overexpression suppresses IL-3-induced STAT5 target gene expression. |
Yeast two-hybrid, co-immunoprecipitation, transcriptional reporter assays, overexpression in cell lines |
The EMBO journal |
Medium |
11726519
|
| 2002 |
SMRT directly interacts with the androgen receptor (AR) ligand-binding domain; the SMRT C-terminal ID2 region mediates interaction; SMRT overexpression inhibits DHT-dependent AR transactivation by inhibiting AR N/C interaction and competing with p160 coactivators; a mutation in the SMRT ID2 corepressor motif abolishes interaction. |
GST pulldown, mammalian two-hybrid, transcriptional reporter assays, co-immunoprecipitation |
The Journal of biological chemistry |
Medium |
12441355
|
| 2004 |
SMRT and N-CoR are regulated by distinct kinase signaling pathways: MEKK1 activation leads to SMRT phosphorylation, dissociation from transcription factor partners in vivo and in vitro, and nuclear-to-cytoplasmic redistribution; N-CoR is refractory to all these MAPK cascade effects. |
Co-immunoprecipitation, in vitro binding assays, subcellular fractionation, kinase assays |
The Journal of biological chemistry |
Medium |
15491994
|
| 2001 |
SMRT is phosphorylated in vivo and in vitro at a CK2 motif centered on serine 1492 within the nuclear receptor interaction domain; CK2-mediated phosphorylation stabilizes SMRT interaction with nuclear hormone receptors. |
In vitro phosphorylation assays, mutagenesis, co-immunoprecipitation |
Molecular and cellular biochemistry |
Medium |
11451368
|
| 2004 |
SMRT binds to the C/EBPβ TAD domain and Nrf2 Neh4/5 domain; glucocorticoid-activated GR recruits SMRT to the GSTA2 promoter to repress C/EBPβ- and Nrf2-mediated GSTA2 induction; siRNA knockdown of SMRT abolishes repression. |
Co-immunoprecipitation, ChIP, GST pulldown, siRNA knockdown, transcriptional reporter assays |
Molecular and cellular biology |
High |
15870285
|
| 2008 |
TBL1 and TBLR1 phosphorylation at the promoter level (e.g., by PKCδ for TBLR1) triggers ubiquitylation and degradation of NCoR/SMRT, enabling corepressor dismissal as a prerequisite for gene activation across multiple signaling pathways (Notch, NF-κB, nuclear receptor ligands). |
ChIP, co-immunoprecipitation, ubiquitylation assays, siRNA knockdown, kinase assays |
Molecular cell |
High |
18374649
|
| 2011 |
Crystal structure of the tetrameric oligomerization domain of TBL1 reveals how it interacts with both SMRT and GPS2; NMR structure of the GPS2-SMRT interface defines assembly mechanism and stoichiometry of the core repression complex. Mutagenesis and functional assays validate the structural model. |
X-ray crystallography, NMR spectroscopy, computational docking, mutagenesis, functional assays |
Nature structural & molecular biology |
High |
21240272
|
| 2005 |
SMRT interacts with PXR through PXR's ligand-binding domain and SMRT's nuclear receptor-interacting domain 2; the PXR-SMRT interaction is disrupted by PXR ligands (Rif, CTZ), causing exchange of SMRT for the p160 coactivator RAC3; deletion of AF-2 helix enhances SMRT binding; SMRT overexpression inhibits PXR transactivation of CYP3A4 and siRNA depletion enhances it. |
GST pulldown, yeast two-hybrid, mammalian two-hybrid, co-localization, siRNA knockdown, transcriptional reporter assays |
Molecular pharmacology |
Medium |
16219912
|
| 2008 |
Cdk2 phosphorylates SMRT at multiple sites required for interaction with the peptidyl-prolyl isomerase Pin1; Pin1 interaction decreases SMRT protein stability and reduces SMRT-dependent transcriptional repression; Her2/Neu/ErbB2 receptor activation leads to SMRT destabilization via this Cdk2-Pin1 cascade. |
Co-immunoprecipitation, in vitro binding assays, mutagenesis, protein stability assays, transcriptional reporter assays |
The Journal of cell biology |
Medium |
18838553
|
| 2008 |
SMRT repression of nuclear receptors via its receptor interaction domain (RID) controls the adipogenic set point; SMRT(mRID) knock-in mice disrupting NHR interaction develop widespread metabolic defects including increased adiposity (70%), reduced respiration, and altered insulin sensitivity; MEFs from SMRT(mRID) mice display dramatically increased adipogenic capacity. |
Knock-in mouse model (RID mutation), metabolic phenotyping, MEF differentiation assays |
Proceedings of the National Academy of Sciences of the United States of America |
High |
19066220
|
| 2010 |
SMRT expression and its occupancy on PPAR target gene promoters increase with age; selective disabling of SMRT's RID1 (SMRT(mRID1)) shifts repression to RID2-associated receptors (notably PPARs), causing premature aging-related metabolic diseases with reduced mitochondrial function; SMRT(mRID1) cells show increased susceptibility to oxidative damage rescued by PPAR activation or antioxidant treatment. |
Knock-in mouse model, ChIP, metabolic and mitochondrial function assays, antioxidant rescue experiments |
Cell metabolism |
High |
21109196
|
| 2012 |
SMRT is required for full agonist-dependent ERα transcriptional activation; SMRT is recruited (along with ERα and SRC-3) to estrogen-responsive promoters in MCF-7 cells; SMRT depletion (but not HDAC1 or HDAC3 depletion) reduces estradiol-stimulated ERα activity and attenuates estrogen-dependent MCF-7 cell proliferation in a cell-type-specific manner. |
ChIP, siRNA knockdown, transcriptional reporter assays, cell proliferation assays |
Molecular and cellular biology |
Medium |
17591692
|
| 2004 |
In frog development, unliganded thyroid hormone receptor recruits N-CoR/SMRT-TBLR1 complexes to chromatinized TR target promoters in vivo, accompanied by histone deacetylation and gene repression; T3 treatment dissociates these complexes and activates gene expression during metamorphosis. |
Frog oocyte chromatin injection, ChIP assays during spontaneous and T3-induced metamorphosis, dominant-negative constructs |
Molecular and cellular biology |
High |
15060155
|
| 2016 |
NCOR1 and NCOR2 redundantly mediate RA-dependent repression of Fgf8 during somitogenesis; Ncor1;Ncor2 double mutants generated by CRISPR/Cas9 exhibit increased Fgf8 expression and FGF signaling; embryo ChIP reveals NCOR1/2 (but not coactivators) are recruited to the Fgf8 RARE in RA-dependent manner, whereas coactivators (not NCOR1/2) are recruited to an activated RARE near Rarb. |
CRISPR/Cas9 double knockout, embryo ChIP, CRISPR deletion of Fgf8 RARE, phenotypic analysis |
Developmental biology |
High |
27506116
|
| 2014 |
In zebrafish, ncor2 is required for hematopoietic stem cell emergence in the AGM region; ncor2 knockdown upregulates fos transcription by increasing histone acetylation at the fos promoter, enhancing Vegfd signaling, which promotes Notch-dependent arterial endothelial fate and suppresses hemogenic endothelial specification. |
Zebrafish morpholino knockdown, ChIP (histone acetylation), epistasis experiments with Vegfd and Notch pathway inhibitors/activators |
Blood |
Medium |
25006126
|
| 2019 |
NCOR1 and NCOR2 loss specifically in GABAergic neurons reduces GABRA2 expression in lateral hypothalamus GABAergic neurons, causing neuron hyperexcitability and impaired hippocampal LTP through a monosynaptic LH-GABAergic to CA3-GABAergic projection; optogenetic activation of this projection causes memory deficits, and targeted manipulation of LH or CA3 neuron activity reverses memory deficits. |
Cell-type-specific conditional knockout, optogenetics, electrophysiology (LTP), Western blot, behavioral assays |
Nature neuroscience |
High |
30664766
|
| 2012 |
Wnt5a-induced CaMKII directly phosphorylates SMRT at Ser-1407, triggering translocation of SMRT from nucleus to cytoplasm and proteasomal degradation; this destabilizes SMRT and derepresses Notch1 signaling by enhancing Notch1-IC/RBP-Jk association and suppressing RBP-Jk/SMRT association. |
Kinase assay, phospho-site mutagenesis, co-immunoprecipitation, subcellular fractionation, proteasome inhibitor experiments, transcriptional reporter assays |
The Journal of biological chemistry |
Medium |
22888005
|
| 2010 |
SMRT forms a protein homodimer; Erk2 phosphorylation disrupts SMRT self-dimerization in vitro and in vivo, resulting in a reorganized corepressor complex with reduced sedimentation coefficient, partial release of HDAC3, TBL-1, and TBLR-1, and inhibition of transcriptional repression. |
Co-immunoprecipitation, sedimentation analysis (sucrose gradient), in vitro binding and kinase assays, transcriptional reporter assays |
Molecular and cellular endocrinology |
Medium |
20965228
|
| 2016 |
All components of the NCoR/SMRT corepressor complex (HDAC3, GPS2, NCoR, SMRT, TBL1, TBLR1) interact with HPV E8^E2C protein in an E8-domain-dependent manner; this interaction is required for E8^E2C-mediated inhibition of both viral transcription and HPV origin replication; a dominant-negative NCoR fragment activates transcription and replication only from wild-type but not NCoR/SMRT-binding-deficient E8^E2C genomes. |
Proteomics (co-precipitation/mass spectrometry), co-immunoprecipitation, co-localization, siRNA knockdown, viral replication assays |
PLoS pathogens |
High |
27064408
|
| 2014 |
NCoR1 is the principal mediator of thyroid hormone sensitivity in liver in vivo, while SMRT plays little independent role in TH signaling; however, combined deletion of both SMRT and NCoR1 in liver greatly accentuates hepatic lipid synthesis, indicating cooperative control of hepatic lipid content through regulation of multiple nuclear receptors including TR. |
Liver-specific conditional knockout mice (SMRT-only, NCoR1-only, double KO), global SMRT KO, metabolic and gene expression analysis |
Molecular and cellular biology |
High |
25421714
|
| 2021 |
GPS2 and SMRT co-occupy candidate enhancers with coactivators CBP and MED1 but antagonistically repress eRNA transcription-coupled H3K27 acetylation; corepressor depletion or inflammatory signaling triggers enhancer activation via a similar mechanism; depletion of SMRT/GPS2 causes derepression of inflammatory genes (Ccl2) in macrophages. |
ChIP-seq, CRISPR genome editing, transcriptional interference, 4C-seq, cistrome analysis, siRNA knockdown, in vivo macrophage-selective eRNA depletion in ob/ob mice |
Molecular cell |
High |
33503407
|
| 2018 |
Crystal structures of two SMRT repression domain 3 (SRD3c) GSI-containing peptides in complex with HDAC4 show that these peptides form β-hairpin structures blocking the catalytic entry site of HDAC4 at class IIa HDAC-specific residues; SMRT binding does not activate the cryptic deacetylase activity of HDAC4, and mutagenesis confirms critical residues (including Arg1369) for optimal binding to HDAC4 and HDAC5. |
X-ray crystallography, mutagenesis, binding/interaction assays |
Nucleic acids research |
High |
30321390
|
| 2022 |
NCOR2 inhibits antitumor treatment by regulating HDAC3 to repress IRF-1-dependent gene expression and interferon signaling; reducing NCOR2 or impairing its interaction with HDAC3 (via adeno-associated viral NCOR2-HDAC3 competitor) enhances chemotherapy responsiveness and restores antitumor immunity by permitting transcription of IRF-1-regulated proapoptosis and inflammatory genes. |
Functional proteomic screening of patient-derived organoids, knockdown, AAV competitor construct, in vivo tumor models, gene expression assays |
Nature cancer |
High |
35618935
|
| 2008 |
VDR-bound SMRT represses CYP24A1; vitamin D3 activates CYP24A1 by dissociating SMRT from VDR at the promoter; PXR 'locks' SMRT onto the CYP24A1 promoter by preventing ligand-dependent dissociation of SMRT from VDR, thereby attenuating vitamin D3 activation; this mechanism was confirmed in Pxr+/+ vs Pxr-/- mice. |
ChIP, co-immunoprecipitation, transcriptional reporter assays, Pxr knockout mouse model |
Molecular pharmacology |
Medium |
18981260
|
| 2020 |
In type 2 diabetic hearts, loss of NCOR2 repression leads to PPARα-mediated upregulation of MCUb (mitochondrial calcium uniporter inhibitory subunit), limiting mitochondrial Ca2+ uptake and impairing glucose oxidation; identified using Cas9-based gene promoter pulldown coupled with mass spectrometry and confirmed by ChIP. |
dCas9-based promoter pulldown with mass spectrometry, ChIP assays, gene therapy with dominant-negative MCUb transgene, metabolic and cardiac function assays |
Diabetes |
Medium |
33303689
|
| 2022 |
NCOR1/2 deletion in B cells limits B cell differentiation via impaired V(D)J recombination, attenuates pre-BCR signaling, enhances STAT5-dependent transcription, causes derepression of EZH2-repressed gene modules including p53 pathway, and leads to aberrant Rag1/Rag2 expression with increased structural variants bearing cryptic recombination signal sequences. |
B cell-specific conditional knockout, whole-genome sequencing, ChIP-seq/ATAC-seq, gene expression analysis, flow cytometry |
Nature immunology |
High |
36316474
|
| 1999 |
The TEL/ETV6 leukemia-associated transcription repressor's central region (maintained in t(12;21)) recruits a repression complex containing SMRT and mSin3A to mediate transcriptional repression, while its HLH domain represses via a SMRT/Sin3A-independent mechanism. |
Co-immunoprecipitation, transcriptional reporter assays, deletion analysis |
Biochemical and biophysical research communications |
Medium |
10544023
|
| 2005 |
AhR activation by TCDD causes physical interaction between AhR and SMRT (corepressor of RARα), sequestering SMRT into nuclear bodies and activating RARα signaling in a ligand-independent manner; AhR and SMRT co-localize in nuclear bodies during this sequestration. |
Co-immunoprecipitation, immunocytochemistry, transcriptional reporter assays, TSA inhibitor experiments |
Biochimie |
Low |
16480812
|
| 2008 |
VDR specifically interacts with SMRT interaction domain 1 (ID1) rather than ID2; specific residues within and outside the extended helix motif of SMRT-ID1 are required for VDR binding; SMRT mutants defective in VDR interaction fail to repress endogenous VDR target genes (osteocalcin, CYP24A1) in vivo. |
One- plus two-hybrid genetic selection, siRNA knockdown, ChIP, mutagenesis, transcriptional reporter assays |
Molecular endocrinology |
Medium |
19098224
|
| 2009 |
Alternative splicing of SMRT generates isoforms with 1, 2, or 3 CoRNR box motifs; all six isoforms are expressed in human cell lines; the full complement of CoRNR boxes rather than individual box identity determines interaction affinity with nuclear receptors; 1-box isoform discriminates between DNA response elements, 2-box isoforms prefer TR complexes, and 3-box isoforms show differential receptor binding. |
RT-PCR (isoform detection), in vitro binding affinity measurements with nuclear receptor-DNA complexes |
Bioscience reports |
Medium |
18752469
|
| 2021 |
Combined global postnatal deletion of NCOR1 and SMRT in adult mice is lethal within ten days; double knockout mice rapidly develop hypoglycemia, hypothermia, and hepatosteatosis with alterations in lipogenesis and beta-oxidation; this phenotype is distinct from HDAC3 knockout mice, implying NCOR1/SMRT together regulate a critical pathway required for adult survival that is separate from HDAC3. |
Tamoxifen-inducible conditional double knockout mouse model (UBC-Cre-ERT2), metabolic phenotyping, hepatic gene expression analysis |
Molecular metabolism |
High |
34390859
|
| 2020 |
HDAC3 protein stability in epidermal cells depends on NCoR and SMRT functioning redundantly; however, point mutations in the NCoR and SMRT deacetylase-activating domains (DAD), which abolish HDAC3's enzymatic function, still permit normal epidermal stratification, indicating HDAC3's roles in this context are largely independent of its histone deacetylase activity. |
Conditional knockout of NCoR/SMRT in epidermis, DAD point-mutation knock-in mice, ChIP-seq, phenotypic analysis |
Genes & development |
High |
32467224
|