| 1993 |
JunB has ~10-fold lower DNA-binding activity than c-Jun due to a small number of amino acid differences in its DNA-binding and dimerization domains. Substituting four amino acids in JunB's DNA-binding/dimerization motifs with the corresponding c-Jun sequences converts JunB into a c-Jun-like activator. JunB attenuates c-Jun trans-activation via its leucine zipper; two glycine residues in the JunB leucine zipper decrease zipper stability, reducing homodimerization and increasing heterodimerization with c-Jun to form inactive heterodimers. |
Domain-swap mutagenesis, transactivation reporter assays, dimerization analysis |
Genes & development |
High |
8383624
|
| 1993 |
The NFAT-1 DNA-binding complex in activated T cells contains JunB and Fra-1 as its inducible nuclear AP-1 component, binding a variant AP-1 site at the 3' end of the NFAT-1 sequence. Mutation of this AP-1 site inhibits both NFAT-1 binding and NFAT-1-driven reporter expression. Antibody supershift experiments identified JunB and Fra-1 specifically within the complex. |
EMSA supershift with AP-1 family-specific antibodies, site-directed mutation of AP-1 site, reporter assay |
Molecular and cellular biology |
High |
8441422
|
| 1999 |
JunB is selectively induced in Th2 (not Th1) cells during differentiation and binds directly to the P1 AP-1 site of the IL-4 promoter, synergizing with c-Maf to activate IL-4 transcription. This synergy requires phosphorylation of JunB at Thr102 and Thr104 by JNK MAP kinase, which facilitates cooperative DNA binding between JunB and c-Maf. Elevated JunB in transgenic mice increased Th2 cytokine expression in developing Th1 cells. |
EMSA, reporter gene assay, site-directed mutagenesis (Thr102/104), JNK kinase assay, transgenic mouse overexpression |
The EMBO journal |
High |
9889198
|
| 1999 |
JunB-deficient embryos die between E8.5–E10.0 due to failure to establish proper vascular interactions with maternal circulation. In trophoblasts, loss of JunB causes deregulation of proliferin, MMP-9, and uPA expression, resulting in defective decidual neovascularization. Downregulation of VEGF-receptor 1 (flt-1) leads to dilated yolk sac vessels. Tetraploid rescue (injection of junB−/− ES cells into WT blastocysts) rescued fetal growth retardation and placental labyrinth defects. |
Genetic knockout (junB−/− mice), gene expression analysis of trophoblast targets, tetraploid blastocyst complementation rescue |
The EMBO journal |
High |
10022836
|
| 2000 |
JunB directly activates transcription of the cyclin-dependent kinase inhibitor p16(INK4a) through three AP-1-like binding sites in the p16 promoter. Increased JunB expression induces premature senescence in primary cells and reduces proliferation in 3T3 cells by abolishing cyclin D-associated kinase activity and reducing pRb hyperphosphorylation. The anti-proliferative effect of JunB is p16-dependent (absent in INK4a−/− cells). |
Gain/loss-of-function in mouse fibroblasts, p16 promoter reporter and deletion analysis, cyclin D kinase assay, pRb phosphorylation assay, INK4a−/− epistasis |
The EMBO journal |
High |
10856241
|
| 2001 |
JunB (and c-Jun) interact physically with Smad3 off-DNA, reducing Smad3/DNA interactions and thereby suppressing TGF-β/Smad3-driven transcription. Conversely, junB−/− fibroblasts show significantly higher Smad-specific promoter transactivation, and rescue of junB expression normalizes this. Thus, TGF-β-induced JunB expression constitutes a negative feedback loop on early Smad-driven gene activation. |
Co-immunoprecipitation (Smad3–JunB interaction), reporter assay in junB−/− vs. wild-type MEFs, JunB rescue experiment |
Oncogene |
Medium |
11402315
|
| 2002 |
JunB can functionally substitute for c-Jun during mouse development in a gene-dosage-dependent manner when knocked into the Jun locus. JunB rescues Jun/Fos-regulated gene expression but not Jun/ATF-regulated gene expression, thereby rescuing liver and cardiac defects of Jun-null mice in vivo and in primary fibroblasts and fetal hepatoblasts in vitro. |
Knock-in strategy, transgenic complementation, gene expression analysis of Jun/Fos vs Jun/ATF targets |
Nature genetics |
High |
11818961
|
| 2002 |
JunB directly activates cyclin A transcription by binding to the CRE element in the cyclin A promoter, driving G2/M cell cycle progression. junB−/− fibroblasts show impaired cyclin A-CDK2 and cyclin B-CDC2 kinase activities and accumulate in S-phase. Re-introduction of inducible JunB-ER(TM) restores cyclin A expression and normal cell cycle distribution. |
junB−/− fibroblasts, cyclin A promoter reporter (CRE binding), kinase activity assays, inducible JunB rescue |
The Journal of biological chemistry |
High |
12121977
|
| 2004 |
Conditional deletion of JunB in osteoblasts and osteoclasts reveals cell-autonomous roles: mutant osteoblasts show elevated p16(INK4a) but decreased cyclin D1 and cyclin A, reduced osteocalcin and bone sialoprotein, and transiently increased Runx2; macrophage-lineage-specific JunB deletion causes osteopetrosis-like phenotype with reduced osteoclast numbers, indicating JunB is a positive regulator of osteoclast activity. |
Conditional (Cre-lox) knockout in osteoblast and macrophage-osteoclast lineages, in vivo and in vitro differentiation assays, gene expression analysis |
The Journal of cell biology |
High |
14769860
|
| 2006 |
During cardiac ischemia-reperfusion (I/R) injury, JunB and FosB accumulate in nuclei of cardiomyocytes, fibroblasts, and endothelial cells. ChIP of the MMP-2 promoter AP-1 site shows JunB homodimers occupying it under control conditions, switching to JunB/FosB heterodimers after I/R, driving enhanced MMP-2 transcription and translation. This induction is blocked by the hydroxyl radical scavenger MPG, implicating oxidant stress. |
Chromatin immunoprecipitation (ChIP) of AP-1 site in MMP-2 promoter, immunohistochemistry, real-time PCR, Western blot, pharmacological inhibition |
American journal of physiology. Heart and circulatory physiology |
Medium |
16699069
|
| 2007 |
In NPM-ALK-positive ALCL, ERK1/2 activation downstream of NPM-ALK transcriptionally upregulates JUNB mRNA, while active mTOR pathway promotes JUNB mRNA translation (shifting it from monosomes/RNPs to large polysomes). JunB knockdown decreases proliferation; mTOR inhibition downregulates JunB protein by shifting its mRNA to monosomes/RNPs. |
NPM-ALK expression, pharmacological ERK/mTOR inhibition, siRNA/shRNA knockdown, polysome fractionation, cell cycle analysis |
Blood |
Medium |
17690253
|
| 2008 |
JunB directly represses G-CSF (Csf3) transcription in epidermal keratinocytes. Loss of epidermal JunB causes elevated systemic G-CSF, leading to myeloproliferative disease and low bone mass. Genetic ablation of G-CSF in JunB epidermal-KO mice prevents myeloproliferative disease but not bone loss, establishing G-CSF as a direct JunB transcriptional target mediating skin-to-hematopoietic organ signaling. |
Epidermal-specific conditional JunB knockout, G-CSF genetic rescue (double mutant), in vitro keratinocyte analysis, promoter studies |
Nature cell biology |
High |
18641637
|
| 2010 |
JunB directly activates transcription of myosin regulatory light chain 9 (Myl9), which controls actomyosin contractility and stress fiber assembly. Conditional ablation of Junb impairs arterial contractility, stress fiber formation, and cellular motility in VSMCs, MEFs, and endothelial cells. Re-expression of either Junb or Myl9 in Junb-deficient cells restores stress fiber formation, motility, and contractile capacity. |
Conditional Junb knockout in vascular cells, Myl9 rescue experiment, vascular contractility assays, stress fiber imaging, ChIP/promoter analysis |
The Journal of clinical investigation |
High |
20551518
|
| 2010 |
JunB overexpression induces skeletal muscle hypertrophy independently of the Akt/mTOR pathway and prevents denervation atrophy. JunB blocks FoxO3 binding to the atrogin-1 and MuRF-1 promoters, thereby reducing protein breakdown. RNAi-mediated JunB knockdown in adult muscles causes atrophy; nuclear exclusion of JunB is observed in atrophying myotubes. |
Electroporation-based OE/KD in adult mouse muscles, ChIP (FoxO3 binding to atrogin-1/MuRF-1 promoters), protein synthesis measurement, denervation model |
The Journal of cell biology |
High |
20921137
|
| 2010 |
Smurf1 ubiquitin E3 ligase interacts with JunB through its PY motif, ubiquitinates JunB, and targets it for proteasomal degradation. Smurf1-deficient mesenchymal stem cells have elevated JunB protein, increased cyclin D1 (a JunB transcriptional target), and enhanced proliferation and osteoblast differentiation. JunB knockdown in Smurf1−/− cells restores osteogenic potential to wild-type level. |
Co-immunoprecipitation, ubiquitination assay, cyclin D1 promoter reporter, JunB knockdown rescue in Smurf1−/− cells |
Journal of bone and mineral research |
High |
20200942
|
| 2012 |
JunB undergoes phosphorylation-dependent ubiquitylation during the G2 phase of the cell cycle. GSK3 phosphorylates a consensus phospho-degron on JunB, and the E3 ubiquitin ligase SCF(FBXW7) mediates JunB ubiquitylation and degradation in G2. Inactivation of this GSK3-FBXW7-JunB axis causes JunB accumulation in G2/M, transcriptional repression of the DNA helicase DDX11, and premature sister chromatid separation. |
Phospho-degron mutagenesis, co-immunoprecipitation with GSK3/FBXW7, ubiquitylation assay, pharmacological/genetic GSK3 inhibition, chromatid cohesion assay |
Oncogene |
High |
22710716
|
| 2012 |
JunB is required for TGF-β-induced epithelial-mesenchymal transition (EMT). JunB depletion by siRNA abrogates TGF-β-induced disruption of cell-cell junctions, actin fiber formation, focal adhesions, and expression of fibrotic proteins. JunB contributes to Smad-mediated repression of inhibitor of differentiation 2 (Id2) through interaction with transcriptional repressor ATF3, and mediates TGF-β induction of fibronectin, fibulin-2, tropomyosin (Tpm1), and integrin-β3. |
siRNA knockdown, co-immunoprecipitation (JunB–ATF3), ChIP, actin/junction immunofluorescence, reporter assay |
The Journal of cell biology |
Medium |
22391036
|
| 2013 |
JUNB in NK and NKT cells directly activates Ifng transcription (IFN-γ is a direct transcriptional target of JUNB). Targeted deletion of Junb in immune cells decreases IFN-γ expression and secretion from NK/NKT cells, reducing STAT1 pathway activation and protecting against concanavalin A-induced hepatitis. Systemic IFN-γ treatment or adenoviral IRF1 delivery restores hepatotoxicity in Junb-deficient mice. |
Conditional immune-cell Junb knockout, ChIP (JUNB at Ifng promoter), cytokine ELISA, STAT1 activation assay, IFN-γ rescue experiment |
The Journal of clinical investigation |
High |
24200694
|
| 2014 |
JunB is required for full LPS-induced expression of Il1b and other pro-inflammatory genes in macrophages, and also modulates alternative macrophage activation markers induced by IL-4. Junb knockdown in macrophages reduces both classical (M1) and alternative (M2) activation gene expression. |
siRNA knockdown in macrophages, LPS/IL-4 stimulation, gene expression analysis, network modeling validation |
Journal of immunology |
Medium |
25472994
|
| 2014 |
JUNB loss-of-function in prostate epithelium combined with Pten loss promotes invasive cancer. JunB deficiency leads to decreased p16(Ink4a) and p21(CIP1) in epithelial cells, increased proliferation, and decreased senescence. Tumor stroma shows increased osteopontin and S100A8/9 expression. |
Prostate epithelium-specific conditional Junb/Pten double knockout, topical Cre delivery, histology, immunostaining for senescence/proliferation markers |
Cell death and differentiation |
Medium |
25526087
|
| 2016 |
Itch is a HECT-type neddylation E3 ligase that neddylates JunB, attenuating its transcriptional activity. Itch-mediated neddylation of JunB also promotes its ubiquitination-dependent proteasomal degradation. |
Neddylation assay in cells, co-immunoprecipitation (Itch–JunB), reporter assay of JunB transcriptional activity, ubiquitination assay |
Cellular signalling |
Medium |
27245101
|
| 2017 |
JunB is required for Th17 cell identity: it directly activates expression of RORγt and RORα (Th17 lineage-specifying receptors) and represses Foxp3. JunB forms a heterodimer with BATF to activate Th17 signature genes; JunB facilitates BATF DNA binding at the Rorc locus. JunB expression is induced by IL-6, is required for IL-23 receptor expression and IL-23-dependent pathogenic Th17 differentiation, but is dispensable for TGF-β1-dependent non-pathogenic Th17 cells. |
Conditional Junb-deficient T cells, ATAC-seq/ChIP-seq (BATF binding at Rorc locus), RNA-seq, EAE and colitis models, cytokine stimulation (IL-6, IL-23, TGF-β1) |
Nature communications / Scientific reports |
High |
28555647 28824171 29234109
|
| 2018 |
JunB in effector Treg cells promotes an IRF4-dependent transcriptional program by facilitating the accumulation of IRF4 at a subset of its target sites, including loci near Icos and Ctla4. JunB promotes Treg effector molecule expression (ICOS, CTLA4) in BATF-dependent and BATF-independent manners. Mice lacking JunB in Treg cells develop multi-organ autoimmunity. |
Treg-specific Junb conditional KO, ChIP-seq (IRF4 binding at Icos/Ctla4 loci with/without JunB), flow cytometry, in vitro Treg differentiation |
Nature communications |
High |
30559442
|
| 2018 |
USP38 is a deubiquitinase that directly associates with JunB, removes Lys-48-linked poly-ubiquitin chains from JunB, and thereby blocks TCR-induced JunB proteasomal turnover. USP38 is required for TCR-induced JunB protein stabilization, Th2 cytokine production, and Th2 development in vitro and in vivo. |
Co-immunoprecipitation (USP38–JunB), deubiquitination assay (K48-specific), USP38 KO mice, Th2 differentiation assay, OVA/HDM asthma model |
The Journal of experimental medicine |
High |
30224386
|
| 2018 |
JUNB governs a TGFβ feed-forward regulatory network in breast cancer: prolonged TGFβ stimulation alters the genome-wide SMAD2/3 binding landscape and induces JUNB expression; JUNB is required for expression of late invasion-mediating genes, including WNT7A and WNT7B. WNT7A/7B overexpression enhances TGFβ-induced invasion, while WNT pathway inhibition reduces it. |
ChIP-seq (SMAD2/3 binding), siRNA knockdown of JUNB, de novo motif analysis, invasion assays, WNT pathway manipulation |
Nucleic acids research |
Medium |
29186616
|
| 2021 |
Persistent JunB activation in fibroblasts drives senescence through concomitant upregulation of p16INK4A and repression of IGF-1. This fibroblast senescence disrupts the stem cell niche, depleting skin stem cell pools. Fibroblast-specific JunB silencing restores IGF-1 and p16 levels and rescues skin stem cell pools and tissue integrity. |
Fibroblast-specific JunB overexpression/silencing in vivo, p16/IGF-1 expression analysis, skin stem cell quantification, niche interaction assays |
Cell reports |
Medium |
34469740
|
| 2021 |
JunB directly activates FBXO21 promoter expression in chondrocytes. The JUNB-FBXO21-ERK axis promotes cartilage degeneration in osteoarthritis: FBXO21 inhibits autophagy by interacting with and phosphorylating ERK. JUNB knockdown reduces FBXO21 expression and attenuates OA-related cartilage degeneration. |
ChIP (JunB at FBXO21 promoter), co-immunoprecipitation (FBXO21–ERK), mass spectrometry, siRNA knockdown, in vivo OA model |
Aging cell |
Medium |
33450132
|
| 2021 |
JUNB is an essential regulator of hemogenic endothelium specialization and endothelial-to-hematopoietic transition during human hematopoiesis in vitro, as identified by integrative chromatin accessibility (ATAC-seq), H3K4me3/H3K27me3 ChIP-seq, and transcriptomic profiling with JUNB loss-of-function. |
ATAC-seq, H3K4me3/H3K27me3 ChIP-seq, RNA-seq, single-cell analysis, JUNB loss-of-function during hPSC-to-HPC differentiation |
Nature communications |
Medium |
35668082
|
| 2022 |
JUNB promotes cell cycle progression by inducing cyclin E1 expression and repressing TGF-β2 gene transcription. High JUNB levels switch TGF-β2 stimulation from an anti-proliferative to a pro-invasive response and promote TGF-β2 mRNA translation. These functions were established by combined transcriptomic, genomic, and functional studies. |
Transcriptomics, ChIP-seq, siRNA/overexpression, cyclin E1 promoter reporter, polysome profiling, in vivo xenograft/metastasis model |
Genome biology |
Medium |
36494864
|
| 2022 |
m6A methylation by METTL3 regulates JUNB expression at the level of mRNA stability (not translation): specific m6A motifs in the JUNB 3'UTR are recognized by distinct m6A reader proteins that control JUNB mRNA stability during TGF-β-induced EMT. JUNB knockdown impairs expression of specific mesenchymal target genes during EMT. |
METTL3 KD, m6A site mutagenesis in 3'UTR, m6A reader protein knockdown, RNA stability assays, siRNA knockdown of JUNB |
The Journal of biological chemistry |
Medium |
36183833
|
| 2004 |
JunB cooperates with the transcriptional coactivator p300 to activate DMP1 (dentin matrix protein 1) transcription during osteoblast differentiation. Phosphorylation of JunB at Ser-79 is required for its interaction with p300. Immunoprecipitation and ChIP confirmed the in vivo interaction of JunB and p300 at the DMP1 promoter. |
Co-immunoprecipitation (JunB–p300), ChIP, Ser-79 phospho-mutant, DMP1 promoter reporter assay |
The Journal of biological chemistry |
Medium |
15308641
|
| 2014 |
JunB stimulates XBP1 expression via the transcription factor C/EBPδ during ER stress, and this JunB–XBP1 axis activates AKT signaling. JunB silencing inhibits AKT activation and activates the pro-apoptotic Bcl-2 protein BAD via dephosphorylation; forced XBP1s expression rescues viability of JunB-deficient β-cells. XBP1 knockdown also reduces AKT phosphorylation, linking JunB to AKT through XBP1. |
siRNA knockdown (JunB, XBP1), adenoviral overexpression, BAD phosphorylation assay, AKT phosphorylation assay, C/EBPδ reporter assay, GLP-1 agonist treatment |
Cell death and differentiation |
Medium |
24786832
|
| 2019 |
JunB plays a crucial role in Treg cell development by facilitating IL-2 production and CD25 (high-affinity IL-2 receptor subunit) expression in CD4+ T cells. Junb-deficient CD4+ T cells fail to differentiate into Treg cells in vitro unless exogenous IL-2 is supplied; a cell-intrinsic defect confirmed by mixed bone marrow transfer. IL-2/anti-IL-2 complex injection rescued Treg expansion and alleviated DSS colitis in Junbfl/flCd4-Cre mice. |
Conditional Junb KO (Cd4-Cre), in vitro Treg differentiation ±IL-2, mixed bone marrow chimera, IL-2 complex rescue, DSS colitis model |
Mucosal immunology |
Medium |
31285535
|
| 2022 |
JunB directly inhibits expression of apoptosis-promoting genes, including Bcl2l11 (encoding Bim), in T helper cells by promoting IRF4 DNA binding at the Bcl2l11 locus. JunB is required for clonal expansion of Th1, Th2, and Th17 cells; TCR-stimulated Junb-deficient CD4+ T cells are more sensitive to apoptosis. |
Conditional Junb KO, flow cytometry (apoptosis, proliferation), ChIP (IRF4 at Bcl2l11 locus in the presence/absence of JunB), immunization models |
Frontiers in immunology |
Medium |
35837408
|
| 2012 |
CARMA1 deficiency reduces JunB protein stability by enhancing its ubiquitination and degradation, impairing TCR-induced Th2 cytokine production and differentiation. JunB stability is regulated downstream of CARMA1 signaling. |
CARMA1-deficient T cells, ubiquitination assay of JunB, JunB protein stability measurement, Th2 differentiation assay |
Journal of immunology |
Medium |
22371397
|
| 2023 |
Bmal1 (core circadian clock gene) directly regulates Junb transcription in macrophages, controlling diurnal variation in ConA-induced hepatitis. JunB in macrophages promotes inflammation by regulating AKT and ERK signaling pathways. Macrophage-specific Junb knockdown blunts the time-of-day-dependent effect of ConA-induced liver injury. |
Myeloid-specific Bmal1 and Junb conditional KO/KD, ChIP (Bmal1 at Junb promoter), AKT/ERK signaling assays, ConA hepatitis model |
JHEP reports |
Medium |
37791375
|
| 2023 |
VCAM-1 regulates JunB-mediated IL-8 promoter activity and expression in human retinal endothelial cells. JunB-driven IL-8/CXCL1 signaling downstream of VCAM-1 controls retinal endothelial cell sprouting and pathological neovascularization. Intravitreal VCAM-1 siRNA decreases VCAM-1–JunB–CXCL1 signaling and reduces OIR-induced retinal neovascularization. |
siRNA knockdown (VCAM-1, JunB), IL-8 promoter reporter assay, RNA-seq, intravitreal siRNA injection, OIR mouse model |
Communications biology |
Medium |
37179352
|
| 2024 |
NAT10-mediated ac4C modification of JUNB mRNA increases its expression in TNBC. JunB then upregulates LDHA transcription, promoting glycolysis and immunosuppression. Loss of NAT10 inhibits JunB expression and TNBC tumor progression; the combination of NAT10 inhibitor remodelin and CTLA-4 antibody synergistically activates T cells. |
NAT10 KO/overexpression, ac4C sequencing, ChIP/reporter for JunB-driven LDHA, in vitro and in vivo tumor models, T cell functional assays |
Journal of experimental & clinical cancer research |
Medium |
39363363
|
| 2024 |
MEK inhibition prevents CAR-T cell exhaustion and terminal differentiation by downregulating c-Fos and JunB. Overexpression of JunB in CAR-T cells counteracts MEK inhibition effects. Cut-and-Tag assay shows that MEK inhibition reduces JunB-driven gene programs associated with exhaustion, differentiation, anergy, glycolysis, and apoptosis in CAR-T cells. |
MEKi treatment, JunB/c-Fos overexpression in CAR-T cells, Cut-and-Tag (JunB ChIP-seq), single-cell transcriptomics, tumor efficacy assays |
Signal transduction and targeted therapy |
Medium |
39438476
|