Affinage

HEXIM1

Protein HEXIM1 · UniProt O94992

Length
359 aa
Mass
40.6 kDa
Annotated
2026-06-10
100 papers in source corpus 47 papers cited in narrative 47 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

HEXIM1 is the central protein component of the 7SK small nuclear ribonucleoprotein that sequesters the transcription elongation kinase P-TEFb (CDK9/Cyclin T) in a catalytically inactive reservoir, thereby setting a rate-limiting control point for RNA polymerase II elongation (PMID:14580347, PMID:12832472). Inhibition is strictly RNA-dependent: HEXIM1 first binds 7SK snRNA through an arginine-rich motif within its N-terminal region that recognizes a conserved GAUC element in the 5' hairpin, while its C-terminal coiled-coil domain forms a homodimer that engages the cyclin boxes of Cyclin T1/T2 (PMID:15201869, PMID:15965233, PMID:17724342, PMID:19883659, PMID:20675720). RNA binding by the HEXIM1 dimer at two high-affinity 7SK sites triggers a conformational rearrangement that relieves intrinsic inter-monomer autoinhibition and unmasks a conserved PYNT peptide which contacts the CDK9 activation segment near the catalytic cleft to occlude substrate binding (PMID:27791144, PMID:41540012). Assembly is hierarchical—HEXIM1 binding to the 5' hairpin is prerequisite for P-TEFb recruitment to the 3' hairpin—and the resulting complex stably scaffolds LARP7 with a 7SK molecule, a HEXIM1 dimer, and two P-TEFb units (PMID:15965233, PMID:16382153, PMID:18281698). P-TEFb is released by multiple inputs that converge on HEXIM1: PI3K/Akt- and PKC-mediated phosphorylation (at Ser158) that abolishes 7SK binding, competitive displacement by HIV-1 Tat and the BRD4 P-TEFb-binding region that remodels 7SK to block HEXIM1 re-association, and hnRNP- and PPM1G-mediated trapping of free 7SK to sustain activation (PMID:17341462, PMID:17937499, PMID:20808803, PMID:22821562, PMID:17709395, PMID:26324325). Beyond P-TEFb, HEXIM1 acts as a gene-specific transcriptional modulator, repressing nuclear receptor and CIITA-driven programs (ERα, AR, GR, CIITA) through P-TEFb sequestration and, for GR and p53, through direct protein contacts, and it stabilizes p53 by antagonizing HDM2-mediated ubiquitination (PMID:15941832, PMID:17088550, PMID:18757415, PMID:18407829, PMID:22948151, PMID:24844355). HEXIM1 governs cell-fate and stress programs including myogenic and erythroid differentiation, satellite-cell expansion, melanoma suppression under nucleotide stress, and BET-inhibitor-induced transcription-replication conflict, and it nucleates the NEAT1-based HDP-RNP complex that couples foreign-DNA sensing to cGAS-STING innate immune signaling (PMID:20940258, PMID:23023707, PMID:37738561, PMID:27058786, PMID:30463005, PMID:28712728).

Mechanistic history

Synthesis pass · year-by-year structured walk · 17 steps
  1. 2003 High

    Established that HEXIM1 is the protein that converts the 7SK snRNP into a repressor of P-TEFb, defining the existence of an RNA-dependent kinase reservoir controlling transcription elongation.

    Evidence In vitro kinase and in vivo transcription assays with co-IP and yeast two-hybrid showing 7SK-dependent HEXIM1:P-TEFb inhibition and direct binding to the Cyclin T cyclin homology region

    PMID:12832472 PMID:14580347

    Open questions at the time
    • Did not define the HEXIM1 domains responsible for RNA versus kinase binding
    • Mechanism of inhibition at the CDK9 active site unresolved
  2. 2004 High

    Mapped HEXIM1 into separable functional modules—an N-terminal arginine-rich 7SK-binding motif and a C-terminal P-TEFb-binding domain bearing the essential PYNT motif—and reconstituted inhibition from purified components, proving the modular two-step inhibitory architecture.

    Evidence In vitro reconstitution, mutagenesis of the PYNT motif, and NLS-swap experiments showing the Tat TAR-binding domain can substitute for the 7SK-binding motif

    PMID:15169877 PMID:15201869

    Open questions at the time
    • Stoichiometry of the assembled complex not yet defined
    • How RNA binding allosterically licenses P-TEFb binding unknown
  3. 2005 High

    Defined the oligomeric and biophysical basis of the inhibitory complex—a HEXIM1 dimer via a C-terminal coiled-coil, micromolar affinity for Cyclin T1 cyclin boxes, and a 1:2:2 7SK:HEXIM1:P-TEFb stoichiometry—and showed HIV-1 Tat releases P-TEFb by mutually exclusive competition for Cyclin T1.

    Evidence ITC, fluorescence/stopped-flow kinetics, glycerol gradient stoichiometry, charge-removal and coiled-coil mutagenesis, and direct GR co-IP independent of 7SK

    PMID:15855166 PMID:15941832 PMID:15965233 PMID:16362050 PMID:16377779

    Open questions at the time
    • Atomic structure of the Cyclin T-binding interface not yet solved
    • Whether GR repression mechanism generalizes to other transcription factors unclear
  4. 2006 Medium

    Resolved the 7SK RNA architecture underlying ordered assembly, showing HEXIM1 binds the 5' hairpin and is a prerequisite for P-TEFb recruitment to the 3' hairpin.

    Evidence Deletion/mutation analysis of 7SK with in vivo binding and reporter assays

    PMID:16382153

    Open questions at the time
    • Nucleotide-resolution HEXIM1-7SK contact not defined
    • Conformational consequence of binding not measured
  5. 2007 High

    Identified the physiological and viral release pathways and additional regulatory partners, establishing that diverse signaling and trans-acting factors converge to liberate active P-TEFb from the HEXIM1 reservoir.

    Evidence PI3K/Akt phospho-resistant mutant, JAK/STAT pharmacological epistasis in cardiomyocytes, hnRNP MS identification with siRNA, Tat competition assays, NMR structure of the TBD coiled-coil, and CIITA P-TEFb-sequestration assays

    PMID:17088550 PMID:17341462 PMID:17395637 PMID:17459355 PMID:17576689 PMID:17709395 PMID:17724342 PMID:17937499

    Open questions at the time
    • Integration of competing release signals in vivo unresolved
    • Whether HEXIM1 dsRNA promiscuity has a defined physiological RNA target unclear
  6. 2008 Medium

    Connected HEXIM1 to gene-specific transcriptional control and protein turnover, showing it represses ERα and GR via both P-TEFb sequestration and direct contacts, while LARP7 stabilizes the core snRNP and NPM controls HEXIM1 abundance and localization.

    Evidence ChIP in MMTV/HEXIM1 transgenic mammary tissue, GR hinge-region domain mapping, LARP7 immunodepletion, and NPM co-IP with proteasome and fractionation assays

    PMID:18281698 PMID:18371977 PMID:18407829 PMID:18757415

    Open questions at the time
    • Direct versus P-TEFb-mediated contributions to receptor repression not fully separated
    • In vivo relevance of NPM-driven HEXIM1 degradation untested
  7. 2009 High

    Pinpointed the direct 7SK-HEXIM1 contact (U30 to residues 210-220), defined paralog/Cyclin T binding selectivity, and showed HDM2 ubiquitinates HEXIM1 to enhance rather than degrade its inhibitory activity.

    Evidence Site-specific 4-thioU photo-crosslinking in reconstituted complex, ITC/EMSA paralog affinity measurements, and ubiquitination assays with ubiquitin-HEXIM1 fusion

    PMID:19244621 PMID:19617712 PMID:19883659

    Open questions at the time
    • Functional role of HEXIM2 versus HEXIM1 not delineated
    • How HDM2 ubiquitination mechanistically potentiates inhibition unknown
  8. 2010 High

    Defined the RNA conformational logic of activation and the subcellular site of action, showing release activators induce a 7SK rearrangement that blocks HEXIM1 re-association and that active P-TEFb exchange occurs at nuclear speckles, while extending HEXIM1's roles into myogenic differentiation.

    Evidence RNA chemical modification of released snRNP, NMR of the GAUC motif with ARM peptide, speckle immunofluorescence with CDK9 mutants, and HEXIM1-KO C2C12 cells with MyoD/HDAC co-IP and ChIP

    PMID:20201073 PMID:20675720 PMID:20808803 PMID:20940258

    Open questions at the time
    • Whether the 7SK conformational switch is reversible in vivo unclear
    • P-TEFb-independent contribution to myogenic gene control not fully separated
  9. 2012 High

    Identified PKC phosphorylation of Ser158 as a direct switch abolishing 7SK binding, extended HEXIM1 into p53 stabilization, and demonstrated a physiological requirement for HEXIM1 dissociation in muscle satellite-cell expansion.

    Evidence In vitro kinase assay with S158A mutant and PKCθ epistasis, p53 co-IP with HDM2-ubiquitination protection, and HEXIM1 haplodeficient mouse regeneration model

    PMID:22821562 PMID:22948151 PMID:23023707

    Open questions at the time
    • Crosstalk between PKC and PI3K/Akt phosphorylation inputs unresolved
    • Direct p53 contact surface not structurally mapped
  10. 2014 High

    Resolved the atomic structure of the HEXIM1 Cyclin T-binding domain as a continuous parallel coiled-coil with a stammer motif tuning Cyclin T1 affinity, and established an auto-regulatory feedback loop in which P-TEFb release drives HEXIM1 transcription, alongside a distinct AR co-repressor mechanism.

    Evidence 2.1 Å crystal structure with NMR/ITC/AUC, ChIP-seq with AFF4/ELL2 knockdown at the HEXIM1 proximal promoter, and AR co-IP with KDM5B-dependent FOXA1 licensing inhibition

    PMID:22033481 PMID:24515107 PMID:24844355

    Open questions at the time
    • Structure of the full HEXIM1-7SK-P-TEFb complex still unsolved
    • Generality of the feedback loop across cell types untested
  11. 2016 High

    Provided direct evidence that HEXIM1 inhibits CDK9 by occluding substrate binding via the PYNT peptide and uncovered a tumor-suppressive role in melanoma under nucleotide stress.

    Evidence Reciprocal pBpa photo-crosslinking in live cells and reconstituted complexes with MS, and zebrafish melanoma in vivo model with HEXIM1 gain/loss and RNA-binding analysis

    PMID:27058786 PMID:27791144

    Open questions at the time
    • Identity and breadth of HEXIM1-stabilized anti-tumorigenic RNAs unclear
    • Whether substrate occlusion is the sole inhibitory mechanism untested
  12. 2017 High

    Revealed a P-TEFb-independent function: HEXIM1 nucleates the NEAT1-based HDP-RNP complex that links foreign-DNA sensing to cGAS-STING innate immune signaling.

    Evidence IP-MS, RNA-seq, NEAT1-binding mutant analysis, and cGAS-STING pathway activation assays

    PMID:28712728

    Open questions at the time
    • Structural basis of HEXIM1-NEAT1 recognition undefined
    • Whether 7SK and NEAT1 roles are mutually exclusive pools unclear
  13. 2018 Medium

    Connected HEXIM1-controlled transcriptional output to genome stability, showing that loss of HEXIM1 restraint during BET inhibition generates transcription-replication conflicts and replication fork slowing.

    Evidence HEXIM1 knockdown with BRD4 inhibitor, DNA fiber assays, and RAD51 epistasis

    PMID:30463005

    Open questions at the time
    • Direct role of HEXIM1 at replication forks versus indirect transcriptional effect not separated
    • Genes driving the conflict not identified
  14. 2020 Medium

    Identified HEXIM1 as the factor transferring kinase-active P-TEFb from Hsp90 to the 7SK snRNP for suppression, explaining Hsp90-inhibitor sensitivity when HEXIM1 is downregulated.

    Evidence Co-IP of the intermediate complex with HEXIM1 knockdown and Hsp90-inhibitor sensitivity assays

    PMID:32520633

    Open questions at the time
    • Direct biochemical demonstration of the transfer reaction lacking
    • Determinants of the Hsp90-to-7SK handoff unknown
  15. 2023 Medium

    Demonstrated context-dependent dual activity of HEXIM1 in erythropoiesis, where GATA1 co-occupancy determines whether HEXIM1 enforces RNAPII pausing or activates genes, linking it to proliferation and fetal globin control.

    Evidence Genome-wide ChIP of HEXIM1/GATA1/RNAPII with RNA-seq in an erythroid differentiation system and HEXIM1 overexpression

    PMID:37738561

    Open questions at the time
    • Molecular basis of GATA1-dependent activation versus repression unresolved
    • Direct physical HEXIM1-GATA1 interaction not established
  16. 2024 Medium

    Established post-translational control of HEXIM1 stability by USP44, coupling HEXIM1 abundance to USP44 tumor-suppressor activity in oral squamous cell carcinoma.

    Evidence Co-IP MS, USP44 gain/loss with HEXIM1-knockdown epistasis, and in vivo xenograft

    PMID:39722007

    Open questions at the time
    • Ubiquitin sites on HEXIM1 targeted by USP44 not mapped
    • Relationship to HDM2/NPM-mediated turnover unclear
  17. 2026 High

    Resolved how RNA binding allosterically activates HEXIM1, showing the dimer engages two 7SK sites to trigger a central-region rearrangement that releases an autoinhibited, dimer-interface-buried CDK9-binding site, and extended HEXIM1 control to neuronal immediate-early gene induction.

    Evidence NMR with ITC/EMSA and interaction-deficient mutants for the autoinhibition switch; neuronal depolarization with calcium manipulation, CDK9 inhibitor, and HEXIM1/P-TEFb co-IP

    PMID:41540012 PMID:41759739

    Open questions at the time
    • High-resolution structure of the fully assembled active inhibitory complex still absent
    • How calcium signaling mechanistically dissociates HEXIM1 in neurons undefined

Open questions

Synthesis pass · forward-looking unresolved questions
  • How HEXIM1 partitions between its 7SK/P-TEFb reservoir function and its NEAT1/HDP-RNP and gene-specific co-regulatory roles, and what determines the choice among competing inputs, remains unresolved.
  • No structure of the complete 7SK-HEXIM1-P-TEFb-LARP7 assembly
  • Quantitative model integrating phosphorylation, viral, hnRNP and PPM1G release inputs lacking
  • Functional separation of 7SK-bound versus NEAT1-bound HEXIM1 pools unestablished

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003723 RNA binding 8 GO:0140110 transcription regulator activity 6 GO:0098772 molecular function regulator activity 4 GO:0140313 molecular sequestering activity 3 GO:0060090 molecular adaptor activity 2
Localization
GO:0005634 nucleus 3 GO:0005654 nucleoplasm 2 GO:0005829 cytosol 2
Pathway
R-HSA-1643685 Disease 5 R-HSA-74160 Gene expression (Transcription) 4 R-HSA-8953854 Metabolism of RNA 4 R-HSA-1266738 Developmental Biology 3 R-HSA-168256 Immune System 3
Partners
CCNT1CDK9GRLARP7NEAT1NPM1P53PPM1G
Complex memberships
7SK snRNPHDP-RNP (HEXIM1/NEAT1)inactive P-TEFb complex (7SK/HEXIM1/CDK9/Cyclin T)

Evidence

Reading pass · 47 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2003 HEXIM1 inhibits P-TEFb (CDK9/Cyclin T) kinase activity in a process that specifically requires 7SK snRNA to mediate the HEXIM1:P-TEFb interaction; 7SK binding alone is not sufficient to inhibit P-TEFb. HEXIM1 inhibits transcription both in vivo and in vitro, and P-TEFb dissociates from HEXIM1 and 7SK during stress response. In vitro kinase assay, in vivo transcription assay, immunoprecipitation, co-immunoprecipitation Molecular cell High 14580347
2003 MAQ1/HEXIM1 is present in the inactive P-TEFb complex together with CDK9, cyclin T, and 7SK RNA; MAQ1 binds directly to the N-terminal cyclin homology region of cyclin T1 and T2 as shown by yeast two-hybrid and immunoprecipitation; inhibition of transcription releases MAQ1 and 7SK RNA from P-TEFb. Yeast two-hybrid, immunoprecipitation from transfected cell extracts, glycerol gradient sedimentation Molecular and cellular biology High 12832472
2004 HEXIM1 binds 7SK snRNA directly through an RNA-recognition motif at amino acids 152–155; the C-terminal domain (aa 181–359) binds P-TEFb directly; point mutations in the conserved PYNT motif (aa 202–205) abolish P-TEFb binding and inhibition without affecting 7SK recognition. In vitro reconstitution of 7SK-dependent HEXIM1 association to purified P-TEFb and subsequent CDK9 inhibition was achieved. In vitro reconstitution, yeast three-hybrid, gel-shift assay, GST pull-down, yeast two-hybrid, mutagenesis The EMBO journal High 15201869
2004 The first 18 amino acids of HEXIM1's nuclear localization signal constitute a necessary and sufficient 7SK-binding motif that is essential for HEXIM1's inhibitory action. This arginine-rich motif is homologous to the HIV-1 Tat TAR RNA-binding motif, and Tat's TAR-binding domain can substitute for HEXIM1's 7SK-binding motif. In vivo and in vitro binding assays, NLS substitution mutagenesis, transcription assays Molecular and cellular biology High 15169877
2005 HEXIM1 forms a homodimer via a putative coiled-coil region in its C-terminal domain and remains dimeric after binding 7SK. The large inactive P-TEFb complex contains one 7SK molecule, a HEXIM1 dimer, and two P-TEFb molecules with CDK9 phosphorylated at Thr186. The first 172 nucleotides of 7SK are sufficient to bind HEXIM1 and recruit P-TEFb. Conserved residues Tyr271 and Phe208 are required for P-TEFb inhibition but not complex assembly. Mutational analysis, glycerol gradient sedimentation, in vitro kinase assay, stoichiometry analysis The Journal of biological chemistry High 15965233
2005 The C-terminal cyclin T-binding domain (TBD, residues 255–359) of HEXIM1 forms a homodimer and binds the cyclin boxes of Cyclin T1 with a dissociation constant of ~1.2 μM. HIV-1 Tat competes with HEXIM1 for Cyclin T1 binding in a mutually exclusive manner, releasing P-TEFb from the inactive complex. Analytical gel filtration, GST pull-down, isothermal titration calorimetry, fluorescence spectroscopy, stopped-flow kinetics, size exclusion chromatography, HeLa cell functional assay The Journal of biological chemistry High 15855166
2005 HEXIM1 forms oligomers mediated by a predicted coiled-coil region in the C-terminal domain and by 7SK snRNA binding to the basic region. Alanine mutagenesis of conserved leucines in the coiled-coil and RNase A digestion prevent oligomerization. Mutations in the N-terminal part of the coiled-coil abrogate HEXIM1's ability to bind and inhibit P-TEFb. Co-immunoprecipitation, RNase treatment, alanine mutagenesis, transcription assays in cells Nucleic acids research Medium 16377779
2005 The basic arginine-rich motif (ARM) in HEXIM1 is essential for binding to 7SK snRNA, P-TEFb, and inhibition of transcription. The basic region interacts with adjacent acidic regions in the absence of RNA. Removal of positive or negative charges leads to constitutive large-complex sequestration. Loss of acidic charges causes subnuclear localization to nuclear speckles. Charge-removal mutagenesis, co-immunoprecipitation, subcellular localization by immunofluorescence, transcription assays The EMBO journal Medium 16362050
2005 HEXIM1 forms a distinct complex with glucocorticoid receptor (GR) without requiring 7SK RNA, CDK9, or cyclin T1; HEXIM1's arginine-rich NLS directly associates with the ligand-binding domain of GR; HEXIM1 inhibits GR-mediated transcription via this direct protein–protein interaction independently of P-TEFb sequestration. Biochemical co-immunoprecipitation, siRNA knockdown, adenoviral overexpression, co-activator binding competition assay Proceedings of the National Academy of Sciences of the United States of America Medium 15941832
2006 Two distinct RNA elements in the 5' and 3' terminal hairpins of 7SK snRNA direct HEXIM1 and P-TEFb binding, respectively. HEXIM1 binds independently to the G24-C48/G60-C87 distal segment of the 5' hairpin; HEXIM1 binding is a prerequisite for P-TEFb association with the 3' hairpin apical region. In vivo binding assays, deletion and mutation analysis of 7SK, HeLa cell transcription reporter assay Molecular and cellular biology Medium 16382153
2007 HIV-1 Tat directly displaces HEXIM1 from cyclin T1, releasing P-TEFb from the 7SK snRNP both in vitro and in vivo. This depends on Tat's N-terminal activation domain and its high affinity for cyclin T1. Primary blood lymphocytes show reduced 7SK snRNP upon HIV-1 infection. In vitro P-TEFb release assay, co-immunoprecipitation, glycerol gradient sedimentation, HIV infection Nucleic acids research High 17341462
2007 HEXIM1 also binds tightly to the HIV 5' UTR TAR RNA and can recruit and inhibit P-TEFb activity via TAR, suggesting that in the absence of Tat, HEXIM1 represses transcription elongation of HIV LTR via TAR binding. In vitro binding assay, in vitro P-TEFb inhibition assay, competition assay with HEXIM1 and Tat for 7SK binding Nucleic acids research Medium 17576689
2007 HEXIM1 dissociates from the P-TEFb complex under hypertrophic stimuli (mechanical stretch, endothelin-1, phenylephrine) in cardiomyocytes; blocking Jak/STAT signaling with AG490 prevents CLP-1/HEXIM1 release from P-TEFb despite ongoing hypertrophic stimulation, placing JAK/STAT upstream of HEXIM1–P-TEFb dissociation. Immunoprecipitation from rat cardiomyocytes under hypertrophic conditions, Jak2 inhibitor treatment, immunoblot Cardiovascular research Medium 17459355
2007 HEXIM1 inhibits CIITA-mediated MHC class II transcription by sequestering P-TEFb from CIITA; this depends on the intact Cyclin T1-binding domain in HEXIM1 and does not result from a direct HEXIM1–CIITA interaction. Depletion of HEXIM1 by siRNA increases CIITA-mediated transcription. Co-immunoprecipitation, ChIP assay, siRNA knockdown, reporter transcription assay Proceedings of the National Academy of Sciences of the United States of America Medium 17088550
2007 HEXIM1 is a promiscuous double-stranded RNA (dsRNA)-binding protein that binds dsRNA in a sequence-independent manner. Binding to dsRNA or the 7SK 10–48 oligonucleotide induces a large conformational change in HEXIM1 that allows recruitment and inhibition of P-TEFb. HEXIM1 is found in both nuclear and cytoplasmic compartments, where it associates with RNA including miR-16. In vitro binding assays with dsRNA/dsDNA competition, gel shift, subcellular fractionation, immunofluorescence, immunoprecipitation Nucleic acids research Medium 17395637
2007 HMBA activates the PI3K/Akt pathway, which phosphorylates HEXIM1, leading to release of active P-TEFb from the HEXIM1/7SK snRNP complex. A phosphorylation-resistant HEXIM1 mutant blocks HMBA-mediated P-TEFb release and HIV transcription induction. Immunoprecipitation, phosphorylation analysis, mutagenesis, HIV transcription assay, PI3K/Akt pathway inhibitors PLoS pathogens Medium 17937499
2007 hnRNPs A1, A2, Q and R associate with 7SK RNA when P-TEFb–HEXIM1–7SK is dissociated following transcription inhibition or HEXIM1 knockdown; knockdown of both hnRNP A1 and A2 attenuates transcription-dependent dissociation of P-TEFb–HEXIM1–7SK complexes, indicating that hnRNPs trap free 7SK to activate P-TEFb. Mass spectrometry identification, co-immunoprecipitation, siRNA knockdown, glycerol gradient sedimentation Molecular and cellular biology Medium 17709395
2007 NMR solution structure of the HEXIM1 Cyclin T-binding domain (TBD) reveals a parallel coiled-coil homodimer with two segments and a preceding alpha helix. NMR titration, fluorescence, and immunoprecipitation experiments mapped the binding interface to Cyclin T1 on the first coiled-coil segment; electrostatic interactions between an acidic patch on HEXIM1 and positively charged residues on Cyclin T1 drive complex formation, validated by mutagenesis. NMR solution structure determination, NMR titration, fluorescence spectroscopy, co-immunoprecipitation, mutagenesis Proceedings of the National Academy of Sciences of the United States of America High 17724342
2008 LARP7 is a stable component of the 7SK snRNP; P-TEFb and HEXIM1 are reversibly associated. Immunodepletion of LARP7 depleted most 7SK RNA regardless of P-TEFb or HEXIM1 presence. LARP7 knockdown decreased 7SK levels, increased free P-TEFb, and increased Tat transactivation of HIV-1 LTR. Glycerol gradient sedimentation, immunodepletion, siRNA knockdown, HIV LTR reporter assay Nucleic acids research Medium 18281698
2008 Nucleophosmin (NPM) binds HEXIM1 in vitro and in vivo. Overexpression of NPM leads to proteasome-mediated degradation of HEXIM1, activating P-TEFb-dependent transcription. A cytoplasmic AML mutant NPMc+ sequesters HEXIM1 in the cytoplasm, leading to higher RNA Pol II transcription. In vitro and in vivo co-immunoprecipitation, NPM overexpression and knockdown, proteasome inhibitor treatment, subcellular fractionation, reporter transcription assay Journal of molecular biology Medium 18371977
2008 HEXIM1 inhibits estrogen receptor α (ERα)-mediated transcription elongation by inhibiting ERα-stimulated P-TEFb recruitment to promoter and coding regions of ERα target genes, reducing Ser2-phosphorylated RNAPII; this occurs in vivo in mammary epithelium of MMTV/HEXIM1 transgenic mice. ChIP assay, in vivo transgenic mouse model (MMTV/HEXIM1), HEXIM1 siRNA knockdown, P-TEFb kinase assay Cancer research Medium 18757415
2008 The hinge region of glucocorticoid receptor (GR) is essential for its interaction with HEXIM1; HEXIM1 suppresses GR-mediated transcription through two mechanisms: P-TEFb sequestration and direct GR–HEXIM1 protein interaction; PPARγ-dependent gene expression is negatively modulated by HEXIM1 solely via P-TEFb sequestration. Co-immunoprecipitation using domain-deletion and point-mutation constructs, transcription reporter assay, antisense RNA disruption of 7SK Biochemical and biophysical research communications Medium 18407829
2009 HDM2 functions as a specific E3 ubiquitin ligase for HEXIM1, ubiquitinating it on lysine residues within the basic region. HDM2-induced ubiquitination does not lead to proteasome-mediated degradation of HEXIM1; instead, ubiquitin fusion to HEXIM1 enhances its inhibitory activity on P-TEFb-dependent transcription. Ubiquitination assay, co-immunoprecipitation, ubiquitin-HEXIM1 fusion expression, transcription reporter assay Cell cycle (Georgetown, Tex.) Medium 19617712
2009 Nucleotide U30 of 7SK RNA specifically photo-cross-links to amino acids 210–220 of HEXIM1 in the context of both a minimal RNA-binding site and a fully reconstituted 7SK/HEXIM1/P-TEFb complex, directly demonstrating the contact site between 7SK and HEXIM1. Site-specific photo-crosslinking with 4-thioU, in vitro reconstitution of 7SK/HEXIM1/P-TEFb complex Journal of molecular biology High 19244621
2009 Cyclin T1 binds HEXIM1 and HEXIM2 with higher affinity than Cyclin T2 binds the opposite paralog. Importin alpha binds HEXIM1 and HEXIM2, supporting a collaborative nuclear import pathway for Cyclin T. The Cyclin T1–HEXIM1 complex binds 7SK 5' hairpin (nucleotides 23–88) with Kd <0.3 μM. Isothermal titration calorimetry, electrophoretic mobility shift assay (EMSA) with radioactively labelled 7SK, binding specificity analysis Journal of molecular biology Medium 19883659
2010 Release of P-TEFb from the 7SK snRNP by HIV-1 Tat or the Brd4 P-TEFb-binding region is accompanied by a major conformational change in 7SK RNA that blocks re-association of HEXIM1, as measured by chemical modification. Both activators can directly extract P-TEFb from immunoprecipitated 7SK snRNP. In vitro P-TEFb release assay from immunoprecipitated 7SK snRNP, chemical modification of RNA (SHAPE-like), glycerol gradient sedimentation PloS one Medium 20808803
2010 NMR and biochemical analyses show that a repeated GAUC motif in the upper part of the 5'-end hairpin of 7SK is essential for specific HEXIM1 recognition. Binding of the HEXIM1 arginine-rich motif (ARM) peptide induces opening of the GAUC motif and stabilization of an internal loop; a conserved proline-serine sequence in the ARM is essential for binding specificity and the conformational change. NMR spectroscopy, biochemical binding assays, mutagenesis of GAUC motif Nucleic acids research High 20675720
2010 CLP-1/HEXIM1 interacts with MyoD and histone deacetylases (HDACs) at the early stage of C2C12 skeletal muscle cell differentiation. The CLP-1/MyoD/HDAC complex binds to the cyclin D1 gene promoter as shown by ChIP, inhibiting cyclin D1 expression to allow cell cycle exit and myogenic differentiation; HEXIM1 knockout C2C12 cells fail to differentiate. Homologous recombination KO of HEXIM1 in C2C12 cells, co-immunoprecipitation, ChIP assay Journal of cell science Medium 20940258
2010 T-loop phosphorylated CDK9 (Thr186) co-localizes with Cyclin T1 almost exclusively within nuclear speckle domains, where both Brd4 and HEXIM1 interact with P-TEFb, suggesting nuclear speckles are sites of P-TEFb function and exchange between HEXIM1 and Brd4 regulatory complexes. Immunofluorescence deconvolution microscopy, CDK9 kinase-defective mutant expression, Cdk9 inhibitor (flavopiridol) treatment Journal of cellular physiology Medium 20201073
2011 Crystal structure of the HEXIM1 Cyclin T-binding domain (TBD) at 2.1 Å resolution reveals a continuous parallel coiled-coil of nine hepta-repeats with a preceding helix; Lys284 and Tyr291 at heptad 'a' positions stabilize the preceding helix through intermolecular hydrogen bonds. Deletion of the central stammer motif leads to a more stable single coiled-coil and reduced affinity for Cyclin T1. X-ray crystallography (2.1 Å resolution), NMR backbone dynamics, circular dichroism, isothermal titration calorimetry, analytical ultracentrifugation, cross-linking Journal of molecular biology High 22033481
2012 Protein kinase C (PKC) phosphorylates HEXIM1 at serine 158 (S158); phosphorylated HEXIM1 neither binds 7SK snRNA nor inhibits P-TEFb. Phorbol esters, T cell antigen receptor engagement, and constitutively active PKCθ inhibit 7SK snRNP formation and increase P-TEFb-dependent transcription; kinase-negative PKCθ and the S158A HEXIM1 mutant block these effects. In vitro kinase assay, phosphorylation-resistant mutant (S158A), constitutively active and kinase-negative PKCθ expression, co-immunoprecipitation, transcription assay Nucleic acids research High 22821562
2012 HEXIM1 directly interacts with p53 via their C-terminal regions; overexpression of HEXIM1 prevents HDM2-mediated ubiquitination of p53, stabilizing p53 protein and upregulating p53 target genes (Puma, p21); HEXIM1 knockdown inhibits p53 induction and releases cell cycle arrest caused by p53. Co-immunoprecipitation, HEXIM1 overexpression, siRNA knockdown, ubiquitination assay, p53 target gene expression analysis The Journal of biological chemistry Medium 22948151
2012 HEXIM1 controls satellite cell expansion after skeletal muscle injury; dissociation of HEXIM1 from P-TEFb is required for satellite cell proliferation and prevention of premature myogenic differentiation. HEXIM1 haplodeficient muscles show enhanced satellite cell expansion and better regeneration; HEXIM1 overexpression impedes regeneration. HEXIM1 haplodeficient mouse model, satellite cell transplantation, satellite cell proliferation assays, co-immunoprecipitation of HEXIM1/P-TEFb The Journal of clinical investigation Medium 23023707
2014 Release of P-TEFb from the 7SK snRNP leads to increased transcription of HEXIM1 itself from an unannotated proximal promoter via poised RNA Pol II; superelongation complex subunits AFF4 and ELL2 are recruited to this proximal promoter after P-TEFb release and are required for its transcriptional effects. This constitutes an auto-regulatory feedback loop. ChIP-seq, luciferase reporter assay, AFF4/ELL2 knockdown, P-TEFb releasing compound treatment The Journal of biological chemistry Medium 24515107
2014 HEXIM1 functions as an androgen receptor (AR) co-repressor by physically interacting with AR; HEXIM1 inhibits AR-mediated transcription by inducing expression of the histone demethylase KDM5B and inhibiting histone methylation, resulting in inhibition of FOXA1 licensing activity—a mechanism distinct from that involving ERα. Co-immunoprecipitation, ChIP assay, HEXIM1 knockdown (shRNA) and overexpression, KDM5B expression analysis The Biochemical journal Medium 24844355
2015 PPM1G phosphatase directly binds 7SK RNA and HEXIM1 once P-TEFb has been released from the 7SK snRNP; this dual binding activity blocks P-TEFb reassembly onto the snRNP to sustain NF-κB-mediated transcription. ATM kinase regulates the PPM1G–7SK snRNP interaction through site-specific PPM1G phosphorylation. Co-immunoprecipitation, in vitro direct binding assay, NF-κB reporter assay, ATM kinase assay, ChIP Molecular and cellular biology Medium 26324325
2016 An evolutionary conserved HEXIM1 peptide (the PYNT sequence, residues 202–210) contacts the activation segment of CDK9 near the catalytic cleft, as shown by photo-crosslinking of an incorporated photoreactive amino acid (pBpa) in live cells, cell extracts, and in vitro reconstituted complexes. Reciprocally, HEXIM1 is cross-linked by a photoreactive amino acid at CDK9 W193. This provides direct evidence that HEXIM1 inhibits CDK9 by interfering with substrate binding. Unnatural amino acid incorporation (pBpa), photo-crosslinking in live cells and in vitro reconstituted complexes, mass spectrometry Proceedings of the National Academy of Sciences of the United States of America High 27791144
2016 Under nucleotide stress, HEXIM1 is induced to form an inhibitory complex with P-TEFb to suppress elongation at tumorigenic genes in melanoma; HEXIM1 overexpression suppresses melanoma formation in zebrafish model in vivo, while HEXIM1 inactivation accelerates tumor onset. Anti-tumorigenic RNAs are stabilized by binding to HEXIM1. Zebrafish melanoma in vivo model, HEXIM1 overexpression/knockdown, P-TEFb complex analysis, RNA-binding assay Molecular cell Medium 27058786
2017 HEXIM1 and the long non-coding RNA NEAT1 form the HDP-RNP complex containing DNA-PK subunits (DNAPKc, Ku70, Ku80) and paraspeckle proteins (SFPQ, NONO, PSPC1, RBM14, MATRIN3). Binding of HEXIM1 to NEAT1 is required for HDP-RNP assembly. The HDP-RNP interacts with cGAS and PQBP1; upon foreign DNA stimulation the complex is remodeled, releasing paraspeckle proteins, recruiting STING, and activating DNAPKc and IRF3 through the cGAS-STING pathway. Immunoprecipitation, mass spectrometry, RNA sequencing, HEXIM1 NEAT1-binding mutant analysis, cGAS-STING pathway activation assay Molecular cell High 28712728
2018 BET inhibition (specifically BRD4 inhibition) releases P-TEFb from its inhibitor HEXIM1, causing an overall increase in RNA synthesis that creates transcription-replication conflicts; HEXIM1 and RAD51 both promote BET inhibitor-induced replication fork slowing and prevent a DNA damage response. HEXIM1 knockdown, BRD4 inhibitor treatment, DNA fiber assay (fork slowing), RAD51 and HEXIM1 epistasis Cell reports Medium 30463005
2019 KDM5B (H3K4me2/3 demethylase) negatively regulates HEXIM1 expression at the chromatin level; RNAi knockdown of KDM5B induces HEXIM1 expression, and KDM5B inhibitors induce HEXIM1 expression in cancer cells. KDM5B was validated as an HMBA molecular target using chemical proteomics (biotin pull-down) and surface plasmon resonance. ChIP assay, shRNA knockdown of KDM5B, surface plasmon resonance, biotin-NeutrAvidin pull-down, RT-PCR, western blotting Breast cancer research : BCR Medium 31805991
2020 HEXIM1 mediates transfer of kinase-active P-TEFb from Hsp90 to the 7SK snRNP for its suppression; downregulation of HEXIM1 locks P-TEFb in the Hsp90 complex in the active state, rendering cells highly sensitive to Hsp90 inhibition. This is particularly relevant in triple-negative breast cancer where HEXIM1 is frequently downregulated. Co-immunoprecipitation, HEXIM1 knockdown, Hsp90 inhibitor sensitivity assay Molecular biology of the cell Medium 32520633
2021 Tip110 associates with MEPCE in the 7SK snRNP and promotes conversion of HEXIM1 from dimer/oligomer to monomer, facilitating release of HEXIM1 and P-TEFb from the 7SK snRNP. Tip110 expression is linked to the glutathione metabolic pathway and intracellular redox level, which regulates HEXIM1 dimerization/oligomerization. Co-immunoprecipitation, FRET microscopy, subcellular fractionation, redox pathway analysis Aging and disease Low 34881089
2023 HEXIM1 controls erythroid proliferation by enforcing RNAPII pausing at cell cycle checkpoint genes and increasing RNAPII occupancy at cell cycle progression genes. Overexpression of HEXIM1 promotes erythroid proliferation and fetal globin (γ-globin) expression; GATA1 is a key determinant of whether HEXIM1 represses or activates genes—genes gaining both HEXIM1 and GATA1 show increased expression, while genes gaining HEXIM1 but losing GATA1 show increased pausing and decreased expression. HEXIM1 overexpression, genome-wide ChIP profiling (HEXIM1, GATA1, RNAPII), RNA-seq, erythroid differentiation system Blood Medium 37738561
2024 USP44 deubiquitinase stabilizes HEXIM1 protein, maintaining its higher expression levels in OSCC cells; USP44-mediated stabilization of HEXIM1 accounts for USP44's tumor suppressor activity, as HEXIM1 knockdown reverses the antitumor effects of USP44 overexpression. Co-IP mass spectrometry, label-free quantitative LC-MS/MS, USP44 overexpression/knockdown, HEXIM1 knockdown epistasis, in vivo xenograft Biology direct Medium 39722007
2026 NMR and biophysical analysis reveals that the HEXIM1 homodimer engages two high-affinity sites on 7SK RNA; dual-site binding triggers a conformational rearrangement in HEXIM1's disordered central region that unmasks the CDK9-binding site, which is otherwise sequestered within an inter-monomer dimer interface (autoinhibition). This explains how 7SK binding converts HEXIM1 from an autoinhibited state into a P-TEFb inhibitor. NMR spectroscopy, biophysical binding assays (ITC, EMSA), interaction-deficient mutants Nature communications High 41540012
2026 In neurons, calcium release following depolarization frees P-TEFb from the HEXIM1 inhibitory complex; inhibition of CDK9 significantly reduces immediate early gene (IEG) induction, particularly during repeated depolarization. HEXIM1 plays a role in establishing and resetting the poised RNAPII state for synaptic plasticity gene expression. Neuronal depolarization model, calcium manipulation, CDK9 inhibitor treatment, gene expression analysis, co-immunoprecipitation of HEXIM1/P-TEFb The Journal of biological chemistry Medium 41759739

Source papers

Stage 0 corpus · 100 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2003 Inhibition of P-TEFb (CDK9/Cyclin T) kinase and RNA polymerase II transcription by the coordinated actions of HEXIM1 and 7SK snRNA. Molecular cell 405 14580347
2004 Binding of the 7SK snRNA turns the HEXIM1 protein into a P-TEFb (CDK9/cyclin T) inhibitor. The EMBO journal 266 15201869
2003 MAQ1 and 7SK RNA interact with CDK9/cyclin T complexes in a transcription-dependent manner. Molecular and cellular biology 211 12832472
2008 LARP7 is a stable component of the 7SK snRNP while P-TEFb, HEXIM1 and hnRNP A1 are reversibly associated. Nucleic acids research 207 18281698
2017 HEXIM1 and NEAT1 Long Non-coding RNA Form a Multi-subunit Complex that Regulates DNA-Mediated Innate Immune Response. Molecular cell 192 28712728
2007 HMBA releases P-TEFb from HEXIM1 and 7SK snRNA via PI3K/Akt and activates HIV transcription. PLoS pathogens 187 17937499
2005 Analysis of the large inactive P-TEFb complex indicates that it contains one 7SK molecule, a dimer of HEXIM1 or HEXIM2, and two P-TEFb molecules containing Cdk9 phosphorylated at threonine 186. The Journal of biological chemistry 183 15965233
2007 Tat competes with HEXIM1 to increase the active pool of P-TEFb for HIV-1 transcription. Nucleic acids research 166 17341462
2007 Manipulation of P-TEFb control machinery by HIV: recruitment of P-TEFb from the large form by Tat and binding of HEXIM1 to TAR. Nucleic acids research 132 17576689
2004 A human immunodeficiency virus type 1 Tat-like arginine-rich RNA-binding domain is essential for HEXIM1 to inhibit RNA polymerase II transcription through 7SK snRNA-mediated inactivation of P-TEFb. Molecular and cellular biology 113 15169877
2006 Regulation of polymerase II transcription by 7SK snRNA: two distinct RNA elements direct P-TEFb and HEXIM1 binding. Molecular and cellular biology 105 16382153
2005 Identification of a cyclin T-binding domain in Hexim1 and biochemical analysis of its binding competition with HIV-1 Tat. The Journal of biological chemistry 103 15855166
2005 HEXIM2, a HEXIM1-related protein, regulates positive transcription elongation factor b through association with 7SK. The Journal of biological chemistry 102 15713662
2010 The mechanism of release of P-TEFb and HEXIM1 from the 7SK snRNP by viral and cellular activators includes a conformational change in 7SK. PloS one 96 20808803
2007 The transcription-dependent dissociation of P-TEFb-HEXIM1-7SK RNA relies upon formation of hnRNP-7SK RNA complexes. Molecular and cellular biology 94 17709395
2005 Compensatory contributions of HEXIM1 and HEXIM2 in maintaining the balance of active and inactive positive transcription elongation factor b complexes for control of transcription. The Journal of biological chemistry 89 15713661
2005 Interplay between 7SK snRNA and oppositely charged regions in HEXIM1 direct the inhibition of P-TEFb. The EMBO journal 89 16362050
2016 Stress from Nucleotide Depletion Activates the Transcriptional Regulator HEXIM1 to Suppress Melanoma. Molecular cell 68 27058786
2014 Brd4 and HEXIM1: multiple roles in P-TEFb regulation and cancer. BioMed research international 66 24592384
2005 Oligomerization of HEXIM1 via 7SK snRNA and coiled-coil region directs the inhibition of P-TEFb. Nucleic acids research 62 16377779
2016 HEXIM1 as a Robust Pharmacodynamic Marker for Monitoring Target Engagement of BET Family Bromodomain Inhibitors in Tumors and Surrogate Tissues. Molecular cancer therapeutics 55 27903752
2007 Structure of the Cyclin T binding domain of Hexim1 and molecular basis for its recognition of P-TEFb. Proceedings of the National Academy of Sciences of the United States of America 55 17724342
2004 Ablation of the CLP-1 gene leads to down-regulation of the HAND1 gene and abnormality of the left ventricle of the heart and fetal death. Mechanisms of development 55 15172687
2008 Nucleophosmin interacts with HEXIM1 and regulates RNA polymerase II transcription. Journal of molecular biology 49 18371977
2014 Release of positive transcription elongation factor b (P-TEFb) from 7SK small nuclear ribonucleoprotein (snRNP) activates hexamethylene bisacetamide-inducible protein (HEXIM1) transcription. The Journal of biological chemistry 48 24515107
2012 PKC phosphorylates HEXIM1 and regulates P-TEFb activity. Nucleic acids research 48 22821562
2007 HEXIM1 and the control of transcription elongation: from cancer and inflammation to AIDS and cardiac hypertrophy. Cell cycle (Georgetown, Tex.) 47 17671421
2007 HEXIM1 is a promiscuous double-stranded RNA-binding protein and interacts with RNAs in addition to 7SK in cultured cells. Nucleic acids research 43 17395637
2018 BET Inhibition Induces HEXIM1- and RAD51-Dependent Conflicts between Transcription and Replication. Cell reports 42 30463005
2016 An evolutionary conserved Hexim1 peptide binds to the Cdk9 catalytic site to inhibit P-TEFb. Proceedings of the National Academy of Sciences of the United States of America 42 27791144
2015 PPM1G Binds 7SK RNA and Hexim1 To Block P-TEFb Assembly into the 7SK snRNP and Sustain Transcription Elongation. Molecular and cellular biology 41 26324325
2010 T-loop phosphorylated Cdk9 localizes to nuclear speckle domains which may serve as sites of active P-TEFb function and exchange between the Brd4 and 7SK/HEXIM1 regulatory complexes. Journal of cellular physiology 39 20201073
2010 HEXIM1 targets a repeated GAUC motif in the riboregulator of transcription 7SK and promotes base pair rearrangements. Nucleic acids research 39 20675720
2005 HEXIM1 forms a transcriptionally abortive complex with glucocorticoid receptor without involving 7SK RNA and positive transcription elongation factor b. Proceedings of the National Academy of Sciences of the United States of America 39 15941832
2005 Inhibition of Tat activity by the HEXIM1 protein. Retrovirology 34 15992410
2007 Mutation of the HEXIM1 gene results in defects during heart and vascular development partly through downregulation of vascular endothelial growth factor. Circulation research 33 18079413
2006 Increased HEXIM1 expression during erythroleukemia and neuroblastoma cell differentiation. Journal of cellular physiology 33 16222702
2012 Inhibition of metastasis by HEXIM1 through effects on cell invasion and angiogenesis. Oncogene 30 22964639
2008 HEXIM1 regulates 17beta-estradiol/estrogen receptor-alpha-mediated expression of cyclin D1 in mammary cells via modulation of P-TEFb. Cancer research 30 18757415
2012 Identification of HEXIM1 as a positive regulator of p53. The Journal of biological chemistry 27 22948151
2010 HEXIM1 modulates vascular endothelial growth factor expression and function in breast epithelial cells and mammary gland. Oncogene 27 20453883
2009 Specificity of Hexim1 and Hexim2 complex formation with cyclin T1/T2, importin alpha and 7SK snRNA. Journal of molecular biology 27 19883659
2007 Pivotal role of cardiac lineage protein-1 (CLP-1) in transcriptional elongation factor P-TEFb complex formation in cardiac hypertrophy. Cardiovascular research 27 17459355
2002 Structure, expression, and functional characterization of the mouse CLP-1 gene. Gene 27 12119119
2019 Inhibition of the histone demethylase, KDM5B, directly induces re-expression of tumor suppressor protein HEXIM1 in cancer cells. Breast cancer research : BCR 25 31805991
2012 Cardiac lineage protein-1 (CLP-1) regulates cardiac remodeling via transcriptional modulation of diverse hypertrophic and fibrotic responses and angiotensin II-transforming growth factor β (TGF-β1) signaling axis. The Journal of biological chemistry 21 22308025
2007 Inhibiting lentiviral replication by HEXIM1, a cellular negative regulator of the CDK9/cyclin T complex. AIDS (London, England) 21 17314519
2018 Hexim1, an RNA-controlled protein hub. Transcription 20 29345523
2010 Human T-lymphotropic virus type 1 Tax protein complexes with P-TEFb and competes for Brd4 and 7SK snRNP/HEXIM1 binding. Journal of virology 20 20926576
2009 U30 of 7SK RNA forms a specific photo-cross-link with Hexim1 in the context of both a minimal RNA-binding site and a fully reconstituted 7SK/Hexim1/P-TEFb ribonucleoprotein complex. Journal of molecular biology 20 19244621
2011 HEXIM1 is a critical determinant of the response to tamoxifen. Oncogene 18 21423213
2015 Role of tumor-associated macrophages in the Hexim1 and TGFβ/SMAD pathway, and their influence on progression of prostatic adenocarcinoma. Pathology, research and practice 17 26608417
2014 HEXIM1 plays a critical role in the inhibition of the androgen receptor by anti-androgens. The Biochemical journal 17 24844355
2013 HEXIM1, a New Player in the p53 Pathway. Cancers 17 24202322
2009 Ubiquitination of HEXIM1 by HDM2. Cell cycle (Georgetown, Tex.) 16 19617712
2014 Acute hypoxia affects P-TEFb through HDAC3 and HEXIM1-dependent mechanism to promote gene-specific transcriptional repression. Nucleic acids research 15 25056306
2012 HEXIM1-binding elements on mRNAs identified through transcriptomic SELEX and computational screening. Biochimie 15 22609015
2018 HEXIM1-Tat chimera inhibits HIV-1 replication. PLoS pathogens 14 30395647
2012 Cardiomyocyte-specific overexpression of HEXIM1 prevents right ventricular hypertrophy in hypoxia-induced pulmonary hypertension in mice. PloS one 14 23300697
2011 Hexim-1 modulates androgen receptor and the TGF-β signaling during the progression of prostate cancer. The Prostate 14 22095517
2010 A flexible bipartite coiled coil structure is required for the interaction of Hexim1 with the P-TEFB subunit cyclin T1. Biochemistry 14 20210365
2010 CLP-1 associates with MyoD and HDAC to restore skeletal muscle cell regeneration. Journal of cell science 14 20940258
2013 HEXIM1 down-regulates hypoxia-inducible factor-1α protein stability. The Biochemical journal 13 24015760
2013 Inducible re-expression of HEXIM1 causes physiological cardiac hypertrophy in the adult mouse. Cardiovascular research 12 23585471
2019 HEXIM1 Peptide Exhibits Antimicrobial Activity Against Antibiotic Resistant Bacteria Through Guidance of Cell Penetrating Peptide. Frontiers in microbiology 11 30800117
2017 Ubenimex enhances Brd4 inhibition by suppressing HEXIM1 autophagic degradation and suppressing the Akt pathway in glioma cells. Oncotarget 11 28484091
2011 Structure and dynamics of a stabilized coiled-coil domain in the P-TEFb regulator Hexim1. Journal of molecular biology 11 22033481
2006 Hexim1 sequesters positive transcription elongation factor b from the class II transactivator on MHC class II promoters. Proceedings of the National Academy of Sciences of the United States of America 11 17088550
2020 HEXIM1 controls P-TEFb processing and regulates drug sensitivity in triple-negative breast cancer. Molecular biology of the cell 10 32520633
2016 Autophagy mediates proteolysis of NPM1 and HEXIM1 and sensitivity to BET inhibition in AML cells. Oncotarget 10 27732946
2014 A Cyclin T1 point mutation that abolishes positive transcription elongation factor (P-TEFb) binding to Hexim1 and HIV tat. Retrovirology 10 24985203
2008 Role of the hinge region of glucocorticoid receptor for HEXIM1-mediated transcriptional repression. Biochemical and biophysical research communications 10 18407829
2016 Use of a novel cytotoxic HEXIM1 peptide in the directed breast cancer therapy. Oncotarget 9 26734838
2016 Induction of HEXIM1 activities by HMBA derivative 4a1: Functional consequences and mechanism. Cancer letters 9 27238569
2014 A single point mutation in cyclin T1 eliminates binding to Hexim1, Cdk9 and RNA but not to AFF4 and enforces repression of HIV transcription. Retrovirology 9 24985467
2012 HEXIM1 controls satellite cell expansion after injury to regulate skeletal muscle regeneration. The Journal of clinical investigation 9 23023707
2009 Down-regulation of cardiac lineage protein (CLP-1) expression in CLP-1 +/- mice affords. Journal of cellular and molecular medicine 9 18624753
2023 HEXIM1 is an essential transcription regulator during human erythropoiesis. Blood 7 37738561
2016 Hexim1, a Novel Regulator of Leptin Function, Modulates Obesity and Glucose Disposal. Molecular endocrinology (Baltimore, Md.) 6 26859361
2014 Down-regulation of hypoxia-inducible factor-1 alpha and vascular endothelial growth factor by HEXIM1 attenuates myocardial angiogenesis in hypoxic mice. Biochemical and biophysical research communications 6 25301555
2019 HEXIM1 Diffusion in the Nucleus Is Regulated by Its Interactions with Both 7SK and P-TEFb. Biophysical journal 5 31590891
2017 HMBA is a putative HSP70 activator stimulating HEXIM1 expression that is down-regulated by estrogen. The Journal of steroid biochemistry and molecular biology 5 28213333
2014 Lead optimization of HMBA to develop potent HEXIM1 inducers. Bioorganic & medicinal chemistry letters 5 24503105
2013 Bovine HEXIM1 inhibits bovine immunodeficiency virus replication through regulating BTat-mediated transactivation. Veterinary research 5 23537346
2021 Tip110 Expression Facilitates the Release of HEXIM1 and pTEFb from the 7SK Ribonucleoprotein Complex Involving Regulation of the Intracellular Redox Level. Aging and disease 4 34881089
2025 DAF-18/PTEN protects LIN-35/Rb from CLP-1/CAPN-mediated cleavage to promote starvation resistance. Life science alliance 3 40199585
2024 USP44 regulates HEXIM1 stability to inhibit tumorigenesis and metastasis of oral squamous cell carcinoma. Biology direct 3 39722007
2017 Rapidly progressive course of Trypanosoma cruzi infection in mice heterozygous for hexamethylene bis-acetamide inducible 1 (Hexim1) gene. Microbes and infection 3 28951318
2016 Hexim1 heterozygosity stabilizes atherosclerotic plaque and decreased steatosis in ApoE null mice fed atherogenic diet. The international journal of biochemistry & cell biology 3 28013147
2013 HEXIM1 induces differentiation of human pluripotent stem cells. PloS one 3 23977357
2012 Functional characterization of a human cyclin T1 mutant reveals a different binding surface for Tat and HEXIM1. Virology 3 22342181
2024 An alpha-herpesvirus employs host HEXIM1 to promote viral transcription. Journal of virology 2 38363111
2022 Downregulation of Dihydrotestosterone and Estradiol Levels by HEXIM1. Endocrinology 2 34864989
2020 Non-epigenetic induction of HEXIM1 by DNMT1 inhibitors and functional relevance. Scientific reports 2 33273553
2026 HEXIM1 inter-monomer autoinhibition governs 7SK RNA binding specificity and P-TEFb inactivation. Nature communications 1 41540012
2026 HEXIM1/P-TEFb complex controls RNA polymerase II pause release and immediate early gene induction following neuronal depolarization. The Journal of biological chemistry 1 41759739
2025 DAF-18/PTEN protects LIN-35/Rb from CLP-1/CAPN-mediated cleavage to promote starvation resistance. bioRxiv : the preprint server for biology 1 40027768
2024 HEXIM1 is correlated with Alzheimer's disease pathology and regulates immediate early gene dynamics in neurons. bioRxiv : the preprint server for biology 1 39386727
2022 Overexpression Bombyx mori HEXIM1 Facilitates Immune Escape of Bombyx mori Nucleopolyhedrovirus by Suppressing BmRelish-Driven Immune Responses. Viruses 1 36560640
2017 HEXIM1 Has Different Functions within Different RNA-Protein Complexes. Molecular cell 1 28777948

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