{"gene":"ELK1","run_date":"2026-06-09T23:54:43","timeline":{"discoveries":[{"year":1992,"finding":"The amino-terminal ETS domain of Elk-1 is necessary and sufficient for direct DNA binding, while both the ETS domain and flanking sequences up to amino acid 169 (including a protein-protein interaction domain spanning residues 137-169) are required for ternary complex formation with the c-fos SRE and SRF. A single amino acid exchange in the ETS domain can alter direct DNA-binding affinity without severely affecting SRF-assisted binding.","method":"Domain deletion analysis and mutagenesis with DNA-binding and ternary complex formation assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct mutagenesis and domain dissection with functional binding readouts, foundational mechanistic study replicated in subsequent structural work","pmids":["1630903"],"is_preprint":false},{"year":1993,"finding":"Elk-1 proteins are phosphoproteins that act as substrates and activators of MAP kinases (ERK/p44mpk); purified Elk-1 stimulates MAP kinase autophosphorylation and activation in an ATP/Mg2+-dependent manner. Dephosphorylation studies indicate Elk-1 can activate only tyrosine-phosphorylated MAP kinase.","method":"In vitro kinase assays with purified recombinant proteins; co-immunoprecipitation; dephosphorylation experiments","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — in vitro reconstitution and co-IP from single lab, partially supported by later studies","pmids":["8339245"],"is_preprint":false},{"year":1994,"finding":"Elk-1 proteins physically interact with MAP kinases (ERK1/ERK2); co-immunoprecipitation confirmed specific association. In vitro phosphorylation of Elk-1 by MAP kinase was not regulatory for autonomous DNA-binding activity of Elk-1.","method":"Co-immunoprecipitation with purified recombinant proteins; in vitro phosphorylation assays; EGF-stimulated cell lysate kinase assays with GST-Elk-1","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — reciprocal Co-IP with purified proteins, single lab; the negative finding on DNA binding was also established","pmids":["8208531"],"is_preprint":false},{"year":1995,"finding":"The ETS DNA-binding domain of Elk-1 (residues 1-93) is an independently folded domain of mixed alpha/beta structure; it binds DNA with high affinity (Kd ~0.85×10^-10 M) and specificity without inducing significant DNA bending.","method":"Protein overexpression and purification; CD, NMR, and fluorescence spectroscopy; circular permutation DNA-bending analysis; quantitative DNA-binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structural characterization with quantitative DNA-binding measurements, multiple orthogonal biophysical methods in one study","pmids":["7890710"],"is_preprint":false},{"year":1995,"finding":"Both the MAPK (ERK) and stress-activated protein kinase (SAPK/JNK) pathways converge on Elk-1; purified p54 SAPK-alpha efficiently phosphorylates the Elk-1 C-terminal domain in vitro. Prolonged SAPK activation correlates with sustained Elk-1 phosphorylation and c-fos transcription.","method":"In vitro kinase assay with purified p54 SAPK-alpha; in-gel kinase assays; Western blotting for Elk-1 phosphorylation","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro phosphorylation assay with purified kinase and substrate, corroborated by cell-based correlations","pmids":["7651411"],"is_preprint":false},{"year":1997,"finding":"cAMP activates Elk-1 and induces neuronal differentiation of PC12 cells via a B-Raf- and Rap1-dependent pathway upstream of MAP kinase. Rap1 activated by PKA selectively activates B-Raf but inhibits Raf-1, conferring cell-type specificity.","method":"PC12 cell transfection; dominant-negative and activated mutant expression; Elk-1 reporter assays; MAP kinase activity assays","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — epistasis through dominant-negative constructs and activated mutants, Elk-1 reporter readout, published in high-impact journal and widely replicated","pmids":["9094716"],"is_preprint":false},{"year":1997,"finding":"ELK1 and SAP1a form ternary complexes with SRF on the Egr1 promoter serum response elements (SREI and SREII), and ELK1 and SAP1a also form quaternary complexes on Egr1 SREI. The B-box domain of ELK1 is required for SRF interaction.","method":"Gel mobility shift assays; deletion mutant analysis; in vitro transcription/translation","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — gel-shift and deletion analysis, single lab, extends known SRF interaction to additional promoters","pmids":["9010223"],"is_preprint":false},{"year":1999,"finding":"Calcineurin (protein phosphatase 2B) specifically dephosphorylates Elk-1 at phosphoserine 383, a critical site whose phosphorylation by MAPK promotes transcriptional activity, thereby providing negative cross-talk between Ca2+ signaling and MAPK-mediated Elk-1 activation.","method":"Cotransfection with constitutively active calcineurin; Ca2+ ionophore treatment; Western blotting for phospho-Ser383 Elk-1; c-fos reporter assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — specific phosphorylation site identified with pharmacological and genetic manipulation, multiple orthogonal approaches in one study","pmids":["10329725"],"is_preprint":false},{"year":1999,"finding":"In rat striatal brain slices, glutamate stimulates ERK-dependent phosphorylation of Elk-1 at Ser383 and c-fos induction; this is blocked by the MEK inhibitor PD98059. CaM-K activity positively regulates ERK activation upstream of Elk-1.","method":"Brain slice preparation; pharmacological inhibitors (PD98059, KN62); phospho-specific Western blotting; c-fos mRNA detection","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — semi-in vivo system with pharmacological inhibitors and phospho-specific antibodies, two orthogonal readouts","pmids":["9858538"],"is_preprint":false},{"year":2002,"finding":"EGF-mediated transcriptional activation of Elk-1 requires nuclear calcium. Suppression of nuclear (but not cytosolic) Ca2+ signals by targeted parvalbumin expression inhibits EGF-induced Elk-1 transactivation without affecting ERK phosphorylation, its nuclear translocation, or Elk-1 phosphorylation—indicating that nuclear Ca2+ is required downstream of Elk-1 phosphorylation for full transcriptional activation.","method":"Targeted parvalbumin expression (nuclear vs. cytosolic); GAL4-Elk-1 reporter assay; ERK phosphorylation and nuclear translocation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — spatially targeted Ca2+ buffering with organelle-targeted parvalbumin, multiple orthogonal measurements, dissects nuclear from cytosolic Ca2+ effects","pmids":["11971908"],"is_preprint":false},{"year":2002,"finding":"Menin (encoded by MEN1) inhibits ERK-dependent phosphorylation and activation of Elk-1 without interfering with ERK2 activation itself, acting downstream of MAPK. Menin also inhibits JNK-mediated phosphorylation of c-Jun/JunD through a distinct inhibitory mechanism.","method":"Menin overexpression; in vitro kinase assays for ERK2 and JNK1 activity; Western blotting for Elk-1 phosphorylation; Elk-1 and c-fos reporter assays; N-terminal deletion mutants","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — kinase assays establish MAPK activity unaffected while Elk-1 phosphorylation is blocked, two separate mechanisms mapped with deletion mutants","pmids":["12226747"],"is_preprint":false},{"year":2004,"finding":"Elk-1 is conjugated to SUMO at lysines 230, 249, and/or 254; mutation of all three sites (Elk-1-3R) is required to fully block SUMOylation in vitro and in vivo. SUMO conjugation promotes nuclear retention of Elk-1, and loss of SUMOylation (Elk-1-3R) enhances cytoplasmic shuttling and augments neurite extension in PC12 cells.","method":"In vitro and in vivo SUMOylation assays; heterokaryon nuclear export assays; PC12 neurite extension; SUMO-1/-2 overexpression; mutant Ubc9 coexpression","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution of SUMOylation, site-directed mutagenesis of all three SUMO sites, functional consequence in nucleo-cytoplasmic shuttling and differentiation assay","pmids":["15210726"],"is_preprint":false},{"year":2006,"finding":"ERK pathway activation leads to SUMO loss from Elk-1 simultaneously as ERK promotes Elk-1 phosphorylation/activation, employing a two-step mechanism to fully activate Elk-1. PIASx-alpha acts as a co-activator facilitating this process.","method":"Biochemical analysis of SUMO modification changes upon ERK activation; reporter assays; PIASx-alpha coexpression","journal":"Biochemical Society symposium","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — mechanistic model supported by biochemical data but review/symposium format; supporting data from primary publications","pmids":["16626293"],"is_preprint":false},{"year":2005,"finding":"Elk-1 inhibits smooth muscle-specific gene expression (telokin, SM22alpha) by blocking myocardin-induced promoter activation and by binding to a nonconsensus site in the telokin promoter in an SRF-dependent manner. Differential sensitivity of smooth muscle promoters to Elk-1 depends on both the DNA-binding domain and the SRF-binding B-box.","method":"Overexpression and dominant-negative Elk-1 in SMCs; gel mobility shift assays; chromatin immunoprecipitation; promoter reporter assays; site-directed mutagenesis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP, EMSA, and reporter mutagenesis with functional endogenous gene readouts, multiple orthogonal methods","pmids":["16260603"],"is_preprint":false},{"year":2007,"finding":"Phosphorylated ERK2 directly interacts with PARP-1 and activates it in a DNA-independent manner in a cell-free system; activated PARP-1 in turn dramatically increases ERK2-catalyzed phosphorylation of Elk-1. This PARP-1/ERK2/Elk-1 axis enhances c-fos transcription and histone acetylation in neurons.","method":"Cell-free reconstitution with recombinant PARP-1 and phospho-ERK2; ERK2 kinase assay for Elk-1 phosphorylation; cortical neuron and cardiomyocyte experiments with PARP inhibitors","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cell-free reconstitution with recombinant proteins plus cellular corroboration, novel mechanism of PARP-1 activation identified","pmids":["17244536"],"is_preprint":false},{"year":2012,"finding":"ChIP-seq reveals ELK1 uses two distinct DNA binding modes: one where other ETS factors can bind redundantly, and another unique mode binding sites not occupied by other ETS factors. The unique binding mode controls a distinct subset of genes, including those governing cell migration.","method":"ChIP-seq; loss-of-function experiments; cell migration assays; gene expression profiling","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide ChIP-seq with functional validation of cell migration phenotype upon ELK1 knockdown, multiple orthogonal methods","pmids":["22589737"],"is_preprint":false},{"year":2013,"finding":"TNF-α activates ERK1/2, which phosphorylates and activates Elk-1; activated Elk-1 translocates to the nucleus and binds its motif on the MLCK promoter, activating MLCK transcription and increasing intestinal tight junction permeability.","method":"ERK1/2 pathway inhibitors; Elk-1 siRNA; MLCK promoter reporter assay; ChIP for Elk-1 binding; in vivo intestinal perfusion model","journal":"The American journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP confirmation of Elk-1 binding at MLCK promoter, siRNA knockdown, in vivo corroboration","pmids":["24121020"],"is_preprint":false},{"year":2011,"finding":"DJ-1 interacts with Erk1/2 and is required for nuclear translocation of Erk1/2 upon oxidative stimulation; nuclear Erk1/2 activates Elk1, which promotes SOD1 (Cu/Zn-superoxide dismutase-1) expression as a neuroprotective response.","method":"Co-immunoprecipitation of DJ-1 with Erk1/2; DJ-1 knockdown cells and knockout mice; Elk1 activation assays; SOD1 expression measurement","journal":"Annals of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and genetic KO/KD with multiple functional readouts across cell and animal models","pmids":["21796667"],"is_preprint":false},{"year":2016,"finding":"Reduced Elk-1 expression causes enhanced ITGB6 (beta6 integrin subunit) expression; Elk-1 basally binds the ITGB6 promoter and represses it. Loss of Elk-1 in vivo exaggerates lung fibrosis, identifying Elk-1 as a transcriptional repressor of integrin αvβ6.","method":"ChIP for Elk-1 at ITGB6 promoter; ITGB6 promoter reporter assays; Elk-1 knockdown; Elk1 knockout mouse model of lung fibrosis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP, reporter mutagenesis, and in vivo Elk1-KO model with fibrosis phenotype, multiple orthogonal methods","pmids":["26861876"],"is_preprint":false},{"year":2015,"finding":"VEGF activates Erk/Elk1 in endothelial cells, leading to Elk-1-mediated transcriptional activation of the miR-17-92 cluster; ChIP confirmed Elk-1 occupancy at the miR-17-92 promoter. This upregulation is required for EC proliferation and angiogenic sprouting.","method":"ChIP assay for Elk-1 at miR-17-92 promoter; VEGF stimulation with ERK/ELK1 inhibition; miR-17-92 iEC-KO mice for in vivo angiogenesis","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP confirmation plus genetic mouse model with multiple angiogenesis readouts","pmids":["26472816"],"is_preprint":false},{"year":2019,"finding":"EGFR activates MEK/ERK signaling, which phosphorylates ELK1 at Ser383; phosphorylated ELK1 binds the GDH1 promoter to activate its transcription, thereby promoting glutamine metabolism in glioblastoma. ELK1 knockdown or Ser383 mutation abolishes EGFR-driven glutaminolysis.","method":"ELK1 knockdown; Ser383 point mutation; ChIP for ELK1 at GDH1 promoter; MEK/ERK inhibitors; metabolic assays","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — site-specific mutation plus ChIP plus metabolic functional readout, multiple orthogonal approaches","pmids":["32034306"],"is_preprint":false},{"year":2019,"finding":"PIAS1 is phosphorylated by MAPK/ERK at a novel site Ser503, which determines its E3 ligase activity; PIAS1 then SUMOylates Elk-1 in rat brain, which decreases Elk-1 phosphorylation and downregulates GADD45α expression. Elk-1-SUMO1 reduces hippocampal apoptosis in APP/PS1 Alzheimer's disease model mice.","method":"LC-MS/MS phosphoproteomics; in vitro kinase assay; in vitro SUMOylation assay; lentiviral Elk-1-SUMO1 expression; TUNEL assay in APP/PS1 mice","journal":"British journal of pharmacology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of SUMO modification, novel phosphorylation site identified by MS, in vivo functional validation in AD mouse model","pmids":["30849179"],"is_preprint":false},{"year":2022,"finding":"ELK1 is necessary to recruit CHD8 specifically to ETS motif-containing promoters in human neurons; loss of ELK1 prevents CHD8 from binding these sites. ELK1 and CHD8 functionally cooperate to regulate gene expression at MAPK/ERK target genes.","method":"Conditional loss-of-function and endogenous tagging of CHD8 in iPSC-derived neurons; chromatin accessibility (ATAC-seq); transcriptional profiling; ELK1 knockdown with ChIP for CHD8","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide chromatin profiling and ChIP with genetic loss-of-function, ELK1 shown necessary for CHD8 recruitment","pmids":["36575212"],"is_preprint":false},{"year":2022,"finding":"In retinal ganglion cells, Elk-1 is both necessary and sufficient for neuroprotection and axon regeneration after optic nerve injury; its activity is enhanced by specific phosphorylation site manipulation. Epistasis experiments show Elk-1 acts downstream of PTEN and is inhibited by REST in the survival/regeneration pathway.","method":"In vivo AAV-mediated Elk-1 overexpression and phosphomutant expression; optic nerve crush model; dominant-negative experiments; genetic epistasis with PTEN and REST","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo gain- and loss-of-function with pathway epistasis, single lab","pmids":["36261683"],"is_preprint":false},{"year":2018,"finding":"ERK/ELK1 signaling directs plasma cell differentiation by repressing BACH2; ELK1 controls an active regulatory region within the BACH2 super-enhancer. RNA-seq and ChIP-seq confirmed ELK1-dependent BACH2 repression in IL-2-stimulated human naive B cells.","method":"ChIP-seq for ELK1 at BACH2 super-enhancer; RNA-seq; IL-2 stimulation with ERK pathway inhibitors; BACH2 overexpression rescue","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP-seq and RNA-seq with functional rescue, multiple orthogonal approaches, novel mechanistic connection","pmids":["29129929"],"is_preprint":false},{"year":2018,"finding":"ELK-1 overexpression in mouse hippocampus produces depressive-like behaviors; selective inhibition of ELK-1 activation prevents stress-induced depression-like molecular and behavioral states. ELK-1 mRNA is upregulated in postmortem hippocampus from depressed suicides.","method":"Hippocampal ELK-1 viral overexpression; stress models in mice; ELK-1 selective inhibition; behavioral assays; molecular/synaptic plasticity readouts","journal":"Nature medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo gain- and loss-of-function with behavioral and molecular readouts, single lab, mechanistic placement downstream of ERK","pmids":["29736027"],"is_preprint":false},{"year":2021,"finding":"The lncRNA ACTA2-AS1 facilitates recruitment of the p300/ELK1 complex to the PDGFB promoter after LPS exposure in cholangiocytes; this drives p300-mediated H3K27 acetylation and transcriptional activation of proliferative/fibrogenic genes. The complex was confirmed by co-immunoprecipitation, RNA-IP, and ChIP.","method":"Co-immunoprecipitation of p300 and ELK1; RNA-IP; ChIP for p300/ELK1 occupancy and H3K27ac at PDGFB promoter; ACTA2-AS1 depletion organoids","journal":"Journal of hepatology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, ChIP, and RNA-IP as orthogonal methods; mechanistic link between ELK1, p300 complex, and specific chromatin modification","pmids":["34953958"],"is_preprint":false},{"year":2022,"finding":"SETD8 directly interacts with ELK1 (Co-IP and GST pulldown); ELK1 binds the bach1 promoter to activate its transcription; H4K20me1 (downstream of SETD8) co-occupies the bach1 promoter with ELK1. Mutual inhibition between SETD8 and ELK1 regulates EndMT in diabetic nephropathy.","method":"Co-immunoprecipitation; GST pulldown; ChIP for ELK1 and H4K20me1 at bach1 promoter; dual-luciferase assay with ELK1 binding site deletion","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and GST pulldown confirm SETD8-ELK1 interaction; ChIP and luciferase mutant confirm ELK1 binding at bach1 promoter; single lab","pmids":["35351142"],"is_preprint":false},{"year":2018,"finding":"ERK signaling through ELK4 (SAP-1) and ELK1 in the thymus cell-autonomously suppresses innate-like αβ CD8+ T cell differentiation; mice lacking both ELK4 and ELK1 develop increased innate-like CD8+ T cells. The effect is mediated via ELK4/ELK1-SRF target genes including EGR2.","method":"ELK4 and ELK1 double-knockout mice; T cell development analysis; EGR2 overexpression rescue; ERK pathway inhibition in peripheral CD8+ T cells","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout with cell-autonomous epistasis, rescue experiment with EGR2 overexpression","pmids":["30068599"],"is_preprint":false},{"year":2019,"finding":"Elk-1 transcription factor is identified as a candidate regulator of prodromal transcriptional changes in Huntington's disease (HD); AAV-mediated Elk-1 overexpression in R6/1 mice alleviated transcriptional dysregulation. Exogenous Elk-1 expression exerted beneficial effects in primary striatal HD cell culture.","method":"Transcriptional and chromatin profiling (H3K27ac) in R6/1 mice; AAV-Elk-1 overexpression in vivo; primary striatal HD cell culture","journal":"Proceedings of the National Academy of Sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — integrative chromatin/transcriptional profiling and in vivo/in vitro functional validation with AAV overexpression","pmids":["31744868"],"is_preprint":false},{"year":2022,"finding":"ELK1 directly binds the BCL6 promoter and activates its transcription as part of the MAPK/ERK/ELK1 axis downstream of mutant KRAS; ChIP and reporter assays confirmed ELK1 occupancy and transcriptional regulation of BCL6.","method":"ChIP for ELK1 at BCL6 promoter; luciferase reporter assay; MEK/ERK inhibitors; ELK1 knockdown; KRAS-mutant lung cancer mouse model (LSL-KrasG12D/+)","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP and reporter assay confirm direct ELK1-BCL6 transcriptional regulation; in vivo validation with genetically engineered KRAS mouse model","pmids":["36377663"],"is_preprint":false},{"year":2010,"finding":"ELK1 directly binds to the FADS2 promoter in an allele-specific manner at SNP rs968567; this binding was demonstrated by electrophoretic mobility shift assay, showing the minor allele abolishes ELK1 binding and reduces FADS2 promoter activity.","method":"Electrophoretic mobility shift assay (EMSA); luciferase reporter gene assays; supershift with anti-ELK1 antibody","journal":"Journal of lipid research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — EMSA with supershift and luciferase reporter, single lab, allele-specific binding established","pmids":["19546342"],"is_preprint":false}],"current_model":"ELK1 is an ETS-domain transcription factor that is phosphorylated at Ser383 (and additional sites) by ERK, JNK/SAPK, and p38 MAP kinases, converting it from a transcriptionally repressed to an active state; it forms ternary complexes with SRF on serum response elements to drive immediate-early gene transcription (e.g., c-fos, Egr-1); its activity is negatively regulated by calcineurin-mediated dephosphorylation of Ser383 and by SUMO conjugation (at K230/249/254) which promotes nuclear retention but reduces transcriptional output, with ERK activation simultaneously removing SUMO while adding activating phosphorylation; it also uses two distinct binding modes (SRF-dependent ternary and SRF-independent unique) to control different functional gene classes including cell migration; in neurons it acts downstream of ERK/DJ-1 to regulate antioxidant and survival genes; and it cooperates with chromatin regulators (p300, CHD8, SETD8) at target promoters to drive context-specific transcriptional programmes."},"narrative":{"mechanistic_narrative":"ELK1 is an ETS-domain transcription factor that converts MAP kinase signalling into immediate-early and context-specific transcriptional programmes [PMID:1630903, PMID:7651411, PMID:22589737]. Its amino-terminal ETS domain (residues 1-93) is an independently folded mixed α/β module that binds DNA with high affinity and specificity without bending it, while flanking sequences including a B-box protein-protein interaction domain mediate ternary complex formation with SRF on serum response elements [PMID:1630903, PMID:7890710, PMID:9010223]. ELK1 is a direct substrate of ERK and stress-activated JNK/SAPK kinases, with which it physically associates; phosphorylation—notably at Ser383—activates its transcriptional output and drives target genes such as c-fos [PMID:8339245, PMID:8208531, PMID:7651411, PMID:32034306]. This activation is opposed by calcineurin (PP2B), which specifically dephosphorylates Ser383 to provide negative cross-talk between Ca2+ and MAPK signalling, and full transcriptional activation additionally requires nuclear Ca2+ downstream of phosphorylation [PMID:10329725, PMID:11971908]. ELK1 activity is further gated by SUMO conjugation at lysines 230/249/254, which promotes nuclear retention and dampens output; ERK activation employs a two-step mechanism that strips SUMO while adding activating phosphorylation [PMID:15210726, PMID:16626293]. Through two distinct DNA-binding modes—an SRF-dependent ternary mode and a unique mode at sites not bound by other ETS factors—ELK1 controls separable gene classes, including genes governing cell migration [PMID:22589737]. Beyond classical immediate-early activation, ELK1 acts as a direct transcriptional repressor at promoters such as ITGB6 and smooth-muscle genes, and as an activator at promoters including GDH1, BCL6, MLCK, miR-17-92 and BACH2/BACH1, cooperating with chromatin regulators p300, CHD8 and SETD8 to execute context-specific programmes across endothelial, immune, neuronal, fibrotic and cancer settings [PMID:16260603, PMID:24121020, PMID:26861876, PMID:26472816, PMID:32034306, PMID:36575212, PMID:29129929, PMID:34953958, PMID:35351142, PMID:36377663]. In neurons it functions downstream of an ERK/DJ-1 axis to drive antioxidant and survival responses [PMID:21796667, PMID:36261683].","teleology":[{"year":1992,"claim":"Established the modular architecture underlying ELK1 DNA recognition, defining which domains read DNA directly versus those needed to partner with SRF.","evidence":"Domain deletion and point mutagenesis with DNA-binding and ternary complex assays","pmids":["1630903"],"confidence":"High","gaps":["Did not resolve how phosphorylation alters these binding modes","No structural model of the ternary complex"]},{"year":1995,"claim":"Defined the ETS domain as an autonomous high-affinity DNA-binding fold that engages DNA without inducing bending, anchoring the recognition mechanism structurally.","evidence":"NMR/CD/fluorescence spectroscopy and circular-permutation bending analysis on purified ETS domain","pmids":["7890710"],"confidence":"High","gaps":["Structure of full-length protein not determined","Did not address SRF-bound conformation"]},{"year":1995,"claim":"Placed ELK1 as a convergent substrate of both ERK and stress-activated JNK/SAPK pathways, explaining how distinct stimuli feed the same factor.","evidence":"In vitro kinase assays with purified SAPK/ERK and Elk-1, plus cell-based phosphorylation and c-fos readouts","pmids":["7651411","8339245","8208531"],"confidence":"High","gaps":["Relative contribution of each kinase in vivo unresolved","Full set of phosphoacceptor sites not enumerated here"]},{"year":1997,"claim":"Identified upstream signalling architecture (cAMP/Rap1/B-Raf) feeding ELK1 activation and showed it links to neuronal differentiation, establishing cell-type-specific routing into ELK1.","evidence":"PC12 transfection with dominant-negative/activated mutants and Elk-1 reporter assays","pmids":["9094716"],"confidence":"High","gaps":["Did not identify direct ELK1 target genes for differentiation","Mechanism of B-Raf vs Raf-1 selectivity on ELK1 output unaddressed"]},{"year":1999,"claim":"Showed ELK1 activity is reversibly controlled at a single critical residue, with calcineurin dephosphorylating Ser383 to integrate Ca2+ with MAPK input.","evidence":"Constitutively active calcineurin cotransfection, Ca2+ ionophore, phospho-Ser383 Western and c-fos reporter; brain-slice glutamate/ERK studies","pmids":["10329725","9858538"],"confidence":"High","gaps":["Other phosphosites' regulation by phosphatases not mapped","Specificity of calcineurin for ELK1 in vivo incompletely defined"]},{"year":2002,"claim":"Revealed that ELK1 phosphorylation is necessary but not sufficient, with nuclear Ca2+ required downstream for full transactivation, and that menin can uncouple ERK activity from ELK1 phosphorylation.","evidence":"Compartment-targeted parvalbumin with GAL4-Elk-1 reporter; menin overexpression with kinase and reporter assays","pmids":["11971908","12226747"],"confidence":"High","gaps":["Nuclear Ca2+ effector acting on ELK1 not identified","Mechanism by which menin blocks phosphorylation unresolved"]},{"year":2006,"claim":"Defined SUMOylation as a second, antagonistic layer of control, with ERK simultaneously removing SUMO and adding activating phosphorylation in a two-step activation switch.","evidence":"In vitro/in vivo SUMOylation assays, triple-lysine mutant, heterokaryon export and PC12 neurite assays; PIASx-alpha co-activator model","pmids":["15210726","16626293"],"confidence":"High","gaps":["Symposium synthesis (idx 12) builds on primary data","Deconjugating enzyme and kinetics of SUMO removal not defined"]},{"year":2012,"claim":"Genome-wide mapping resolved that ELK1 uses two binding modes—redundant ETS sites and unique sites—to control separable gene programmes including cell migration.","evidence":"ChIP-seq with loss-of-function, migration assays and expression profiling","pmids":["22589737"],"confidence":"High","gaps":["Determinants directing ELK1 to unique vs redundant sites unknown","Cofactor differences between the two modes not defined"]},{"year":2018,"claim":"Showed ELK1 functions as a direct repressor as well as activator across tissues—repressing BACH2 in B cells, ITGB6 in fibrosis, and smooth-muscle genes—broadening its role beyond immediate-early activation.","evidence":"ChIP/ChIP-seq, reporter mutagenesis, knockdown and Elk1-knockout mouse models with disease phenotypes","pmids":["29129929","26861876","16260603","30068599"],"confidence":"High","gaps":["Switch between activator and repressor functions mechanistically unexplained","Corepressor identity at repressed promoters not defined"]},{"year":2022,"claim":"Established ELK1 as a recruiter of chromatin machinery, showing it is required to bring CHD8, p300 and SETD8/H4K20me1 to specific promoters to execute context-specific transcription.","evidence":"ATAC-seq, ChIP, Co-IP, GST pulldown and RNA-IP in neurons, cholangiocytes and EndMT models","pmids":["36575212","34953958","35351142"],"confidence":"High","gaps":["Direct vs indirect nature of some chromatin-factor interactions not fully resolved","Whether recruitment depends on ELK1 phosphorylation state untested"]},{"year":2022,"claim":"Placed ELK1 as a transcriptional effector of oncogenic and metabolic programmes (GDH1 glutaminolysis, BCL6 downstream of mutant KRAS) and of neuroprotection/regeneration via an ERK/DJ-1/SOD1 axis.","evidence":"ChIP, Ser383 point mutation, metabolic assays, KRAS-mutant and optic-nerve-crush in vivo models; DJ-1 Co-IP and knockout","pmids":["32034306","36377663","21796667","36261683"],"confidence":"High","gaps":["Selectivity of these target promoters across cell types unexplained","How upstream pathway choice dictates ELK1 target repertoire unknown"]},{"year":null,"claim":"It remains unresolved what molecular determinants dictate whether ELK1 activates or represses a given promoter and which cofactor it engages, i.e. how a single MAPK-driven factor is routed into divergent context-specific programmes.","evidence":"No timeline study reconciles the activator/repressor and unique/redundant binding-mode logic mechanistically","pmids":[],"confidence":"Medium","gaps":["No unifying model linking phosphorylation/SUMO state to activator vs repressor outcome","Cofactor selection rules undefined","No structure of ELK1 in complex with chromatin regulators"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,13,15,16,18,20,24,30]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0,3,31]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1,4]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[11,16]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,5,7,20]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,6,15,24,30]}],"complexes":["ELK1-SRF ternary complex"],"partners":["SRF","ERK2","SAP1A","P300","CHD8","SETD8","PIAS1","PARP1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P19419","full_name":"ETS domain-containing protein Elk-1","aliases":[],"length_aa":428,"mass_kda":44.9,"function":"Transcription factor that binds to purine-rich DNA sequences (PubMed:10799319, PubMed:7889942). Forms a ternary complex with SRF and the ETS and SRF motifs of the serum response element (SRE) on the promoter region of immediate early genes such as FOS and IER2 (PubMed:1630903). 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pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/30849179","citation_count":18,"is_preprint":false},{"pmid":"37716490","id":"PMC_37716490","title":"Guben Xiezhuo Decoction inhibits M1 polarization through the Raf1/p-Elk1 signaling axis to attenuate renal interstitial fibrosis.","date":"2023","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37716490","citation_count":17,"is_preprint":false},{"pmid":"33247506","id":"PMC_33247506","title":"c-KIT-ERK1/2 signaling activated ELK1 and upregulated carcinoembryonic antigen expression to promote colorectal cancer progression.","date":"2020","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/33247506","citation_count":17,"is_preprint":false},{"pmid":"38310670","id":"PMC_38310670","title":"ANXA3 interference inactivates ERK/ELK1 pathway to mitigate inflammation and apoptosis in sepsis-associated acute lung injury.","date":"2024","source":"Molecular 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[et al.]","url":"https://pubmed.ncbi.nlm.nih.gov/35306578","citation_count":17,"is_preprint":false},{"pmid":"31289617","id":"PMC_31289617","title":"MicroRNA-873 inhibits colorectal cancer metastasis by targeting ELK1 and STRN4.","date":"2018","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/31289617","citation_count":17,"is_preprint":false},{"pmid":"28954762","id":"PMC_28954762","title":"Integration of EGFR and LIN-12/Notch Signaling by LIN-1/Elk1, the Cdk8 Kinase Module, and SUR-2/Med23 in Vulval Precursor Cell Fate Patterning in Caenorhabditis elegans.","date":"2017","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28954762","citation_count":17,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":55400,"output_tokens":8010,"usd":0.143175,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":17500,"output_tokens":3958,"usd":0.093225,"stage2_stop_reason":"end_turn"},"total_usd":0.2364,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1992,\n      \"finding\": \"The amino-terminal ETS domain of Elk-1 is necessary and sufficient for direct DNA binding, while both the ETS domain and flanking sequences up to amino acid 169 (including a protein-protein interaction domain spanning residues 137-169) are required for ternary complex formation with the c-fos SRE and SRF. A single amino acid exchange in the ETS domain can alter direct DNA-binding affinity without severely affecting SRF-assisted binding.\",\n      \"method\": \"Domain deletion analysis and mutagenesis with DNA-binding and ternary complex formation assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct mutagenesis and domain dissection with functional binding readouts, foundational mechanistic study replicated in subsequent structural work\",\n      \"pmids\": [\"1630903\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Elk-1 proteins are phosphoproteins that act as substrates and activators of MAP kinases (ERK/p44mpk); purified Elk-1 stimulates MAP kinase autophosphorylation and activation in an ATP/Mg2+-dependent manner. Dephosphorylation studies indicate Elk-1 can activate only tyrosine-phosphorylated MAP kinase.\",\n      \"method\": \"In vitro kinase assays with purified recombinant proteins; co-immunoprecipitation; dephosphorylation experiments\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — in vitro reconstitution and co-IP from single lab, partially supported by later studies\",\n      \"pmids\": [\"8339245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Elk-1 proteins physically interact with MAP kinases (ERK1/ERK2); co-immunoprecipitation confirmed specific association. In vitro phosphorylation of Elk-1 by MAP kinase was not regulatory for autonomous DNA-binding activity of Elk-1.\",\n      \"method\": \"Co-immunoprecipitation with purified recombinant proteins; in vitro phosphorylation assays; EGF-stimulated cell lysate kinase assays with GST-Elk-1\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — reciprocal Co-IP with purified proteins, single lab; the negative finding on DNA binding was also established\",\n      \"pmids\": [\"8208531\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"The ETS DNA-binding domain of Elk-1 (residues 1-93) is an independently folded domain of mixed alpha/beta structure; it binds DNA with high affinity (Kd ~0.85×10^-10 M) and specificity without inducing significant DNA bending.\",\n      \"method\": \"Protein overexpression and purification; CD, NMR, and fluorescence spectroscopy; circular permutation DNA-bending analysis; quantitative DNA-binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structural characterization with quantitative DNA-binding measurements, multiple orthogonal biophysical methods in one study\",\n      \"pmids\": [\"7890710\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Both the MAPK (ERK) and stress-activated protein kinase (SAPK/JNK) pathways converge on Elk-1; purified p54 SAPK-alpha efficiently phosphorylates the Elk-1 C-terminal domain in vitro. Prolonged SAPK activation correlates with sustained Elk-1 phosphorylation and c-fos transcription.\",\n      \"method\": \"In vitro kinase assay with purified p54 SAPK-alpha; in-gel kinase assays; Western blotting for Elk-1 phosphorylation\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro phosphorylation assay with purified kinase and substrate, corroborated by cell-based correlations\",\n      \"pmids\": [\"7651411\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"cAMP activates Elk-1 and induces neuronal differentiation of PC12 cells via a B-Raf- and Rap1-dependent pathway upstream of MAP kinase. Rap1 activated by PKA selectively activates B-Raf but inhibits Raf-1, conferring cell-type specificity.\",\n      \"method\": \"PC12 cell transfection; dominant-negative and activated mutant expression; Elk-1 reporter assays; MAP kinase activity assays\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — epistasis through dominant-negative constructs and activated mutants, Elk-1 reporter readout, published in high-impact journal and widely replicated\",\n      \"pmids\": [\"9094716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ELK1 and SAP1a form ternary complexes with SRF on the Egr1 promoter serum response elements (SREI and SREII), and ELK1 and SAP1a also form quaternary complexes on Egr1 SREI. The B-box domain of ELK1 is required for SRF interaction.\",\n      \"method\": \"Gel mobility shift assays; deletion mutant analysis; in vitro transcription/translation\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — gel-shift and deletion analysis, single lab, extends known SRF interaction to additional promoters\",\n      \"pmids\": [\"9010223\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Calcineurin (protein phosphatase 2B) specifically dephosphorylates Elk-1 at phosphoserine 383, a critical site whose phosphorylation by MAPK promotes transcriptional activity, thereby providing negative cross-talk between Ca2+ signaling and MAPK-mediated Elk-1 activation.\",\n      \"method\": \"Cotransfection with constitutively active calcineurin; Ca2+ ionophore treatment; Western blotting for phospho-Ser383 Elk-1; c-fos reporter assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — specific phosphorylation site identified with pharmacological and genetic manipulation, multiple orthogonal approaches in one study\",\n      \"pmids\": [\"10329725\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"In rat striatal brain slices, glutamate stimulates ERK-dependent phosphorylation of Elk-1 at Ser383 and c-fos induction; this is blocked by the MEK inhibitor PD98059. CaM-K activity positively regulates ERK activation upstream of Elk-1.\",\n      \"method\": \"Brain slice preparation; pharmacological inhibitors (PD98059, KN62); phospho-specific Western blotting; c-fos mRNA detection\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — semi-in vivo system with pharmacological inhibitors and phospho-specific antibodies, two orthogonal readouts\",\n      \"pmids\": [\"9858538\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"EGF-mediated transcriptional activation of Elk-1 requires nuclear calcium. Suppression of nuclear (but not cytosolic) Ca2+ signals by targeted parvalbumin expression inhibits EGF-induced Elk-1 transactivation without affecting ERK phosphorylation, its nuclear translocation, or Elk-1 phosphorylation—indicating that nuclear Ca2+ is required downstream of Elk-1 phosphorylation for full transcriptional activation.\",\n      \"method\": \"Targeted parvalbumin expression (nuclear vs. cytosolic); GAL4-Elk-1 reporter assay; ERK phosphorylation and nuclear translocation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — spatially targeted Ca2+ buffering with organelle-targeted parvalbumin, multiple orthogonal measurements, dissects nuclear from cytosolic Ca2+ effects\",\n      \"pmids\": [\"11971908\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Menin (encoded by MEN1) inhibits ERK-dependent phosphorylation and activation of Elk-1 without interfering with ERK2 activation itself, acting downstream of MAPK. Menin also inhibits JNK-mediated phosphorylation of c-Jun/JunD through a distinct inhibitory mechanism.\",\n      \"method\": \"Menin overexpression; in vitro kinase assays for ERK2 and JNK1 activity; Western blotting for Elk-1 phosphorylation; Elk-1 and c-fos reporter assays; N-terminal deletion mutants\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — kinase assays establish MAPK activity unaffected while Elk-1 phosphorylation is blocked, two separate mechanisms mapped with deletion mutants\",\n      \"pmids\": [\"12226747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Elk-1 is conjugated to SUMO at lysines 230, 249, and/or 254; mutation of all three sites (Elk-1-3R) is required to fully block SUMOylation in vitro and in vivo. SUMO conjugation promotes nuclear retention of Elk-1, and loss of SUMOylation (Elk-1-3R) enhances cytoplasmic shuttling and augments neurite extension in PC12 cells.\",\n      \"method\": \"In vitro and in vivo SUMOylation assays; heterokaryon nuclear export assays; PC12 neurite extension; SUMO-1/-2 overexpression; mutant Ubc9 coexpression\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution of SUMOylation, site-directed mutagenesis of all three SUMO sites, functional consequence in nucleo-cytoplasmic shuttling and differentiation assay\",\n      \"pmids\": [\"15210726\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ERK pathway activation leads to SUMO loss from Elk-1 simultaneously as ERK promotes Elk-1 phosphorylation/activation, employing a two-step mechanism to fully activate Elk-1. PIASx-alpha acts as a co-activator facilitating this process.\",\n      \"method\": \"Biochemical analysis of SUMO modification changes upon ERK activation; reporter assays; PIASx-alpha coexpression\",\n      \"journal\": \"Biochemical Society symposium\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — mechanistic model supported by biochemical data but review/symposium format; supporting data from primary publications\",\n      \"pmids\": [\"16626293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Elk-1 inhibits smooth muscle-specific gene expression (telokin, SM22alpha) by blocking myocardin-induced promoter activation and by binding to a nonconsensus site in the telokin promoter in an SRF-dependent manner. Differential sensitivity of smooth muscle promoters to Elk-1 depends on both the DNA-binding domain and the SRF-binding B-box.\",\n      \"method\": \"Overexpression and dominant-negative Elk-1 in SMCs; gel mobility shift assays; chromatin immunoprecipitation; promoter reporter assays; site-directed mutagenesis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP, EMSA, and reporter mutagenesis with functional endogenous gene readouts, multiple orthogonal methods\",\n      \"pmids\": [\"16260603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Phosphorylated ERK2 directly interacts with PARP-1 and activates it in a DNA-independent manner in a cell-free system; activated PARP-1 in turn dramatically increases ERK2-catalyzed phosphorylation of Elk-1. This PARP-1/ERK2/Elk-1 axis enhances c-fos transcription and histone acetylation in neurons.\",\n      \"method\": \"Cell-free reconstitution with recombinant PARP-1 and phospho-ERK2; ERK2 kinase assay for Elk-1 phosphorylation; cortical neuron and cardiomyocyte experiments with PARP inhibitors\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cell-free reconstitution with recombinant proteins plus cellular corroboration, novel mechanism of PARP-1 activation identified\",\n      \"pmids\": [\"17244536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"ChIP-seq reveals ELK1 uses two distinct DNA binding modes: one where other ETS factors can bind redundantly, and another unique mode binding sites not occupied by other ETS factors. The unique binding mode controls a distinct subset of genes, including those governing cell migration.\",\n      \"method\": \"ChIP-seq; loss-of-function experiments; cell migration assays; gene expression profiling\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide ChIP-seq with functional validation of cell migration phenotype upon ELK1 knockdown, multiple orthogonal methods\",\n      \"pmids\": [\"22589737\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"TNF-α activates ERK1/2, which phosphorylates and activates Elk-1; activated Elk-1 translocates to the nucleus and binds its motif on the MLCK promoter, activating MLCK transcription and increasing intestinal tight junction permeability.\",\n      \"method\": \"ERK1/2 pathway inhibitors; Elk-1 siRNA; MLCK promoter reporter assay; ChIP for Elk-1 binding; in vivo intestinal perfusion model\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP confirmation of Elk-1 binding at MLCK promoter, siRNA knockdown, in vivo corroboration\",\n      \"pmids\": [\"24121020\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"DJ-1 interacts with Erk1/2 and is required for nuclear translocation of Erk1/2 upon oxidative stimulation; nuclear Erk1/2 activates Elk1, which promotes SOD1 (Cu/Zn-superoxide dismutase-1) expression as a neuroprotective response.\",\n      \"method\": \"Co-immunoprecipitation of DJ-1 with Erk1/2; DJ-1 knockdown cells and knockout mice; Elk1 activation assays; SOD1 expression measurement\",\n      \"journal\": \"Annals of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and genetic KO/KD with multiple functional readouts across cell and animal models\",\n      \"pmids\": [\"21796667\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Reduced Elk-1 expression causes enhanced ITGB6 (beta6 integrin subunit) expression; Elk-1 basally binds the ITGB6 promoter and represses it. Loss of Elk-1 in vivo exaggerates lung fibrosis, identifying Elk-1 as a transcriptional repressor of integrin αvβ6.\",\n      \"method\": \"ChIP for Elk-1 at ITGB6 promoter; ITGB6 promoter reporter assays; Elk-1 knockdown; Elk1 knockout mouse model of lung fibrosis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP, reporter mutagenesis, and in vivo Elk1-KO model with fibrosis phenotype, multiple orthogonal methods\",\n      \"pmids\": [\"26861876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"VEGF activates Erk/Elk1 in endothelial cells, leading to Elk-1-mediated transcriptional activation of the miR-17-92 cluster; ChIP confirmed Elk-1 occupancy at the miR-17-92 promoter. This upregulation is required for EC proliferation and angiogenic sprouting.\",\n      \"method\": \"ChIP assay for Elk-1 at miR-17-92 promoter; VEGF stimulation with ERK/ELK1 inhibition; miR-17-92 iEC-KO mice for in vivo angiogenesis\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP confirmation plus genetic mouse model with multiple angiogenesis readouts\",\n      \"pmids\": [\"26472816\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"EGFR activates MEK/ERK signaling, which phosphorylates ELK1 at Ser383; phosphorylated ELK1 binds the GDH1 promoter to activate its transcription, thereby promoting glutamine metabolism in glioblastoma. ELK1 knockdown or Ser383 mutation abolishes EGFR-driven glutaminolysis.\",\n      \"method\": \"ELK1 knockdown; Ser383 point mutation; ChIP for ELK1 at GDH1 promoter; MEK/ERK inhibitors; metabolic assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — site-specific mutation plus ChIP plus metabolic functional readout, multiple orthogonal approaches\",\n      \"pmids\": [\"32034306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PIAS1 is phosphorylated by MAPK/ERK at a novel site Ser503, which determines its E3 ligase activity; PIAS1 then SUMOylates Elk-1 in rat brain, which decreases Elk-1 phosphorylation and downregulates GADD45α expression. Elk-1-SUMO1 reduces hippocampal apoptosis in APP/PS1 Alzheimer's disease model mice.\",\n      \"method\": \"LC-MS/MS phosphoproteomics; in vitro kinase assay; in vitro SUMOylation assay; lentiviral Elk-1-SUMO1 expression; TUNEL assay in APP/PS1 mice\",\n      \"journal\": \"British journal of pharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of SUMO modification, novel phosphorylation site identified by MS, in vivo functional validation in AD mouse model\",\n      \"pmids\": [\"30849179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ELK1 is necessary to recruit CHD8 specifically to ETS motif-containing promoters in human neurons; loss of ELK1 prevents CHD8 from binding these sites. ELK1 and CHD8 functionally cooperate to regulate gene expression at MAPK/ERK target genes.\",\n      \"method\": \"Conditional loss-of-function and endogenous tagging of CHD8 in iPSC-derived neurons; chromatin accessibility (ATAC-seq); transcriptional profiling; ELK1 knockdown with ChIP for CHD8\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide chromatin profiling and ChIP with genetic loss-of-function, ELK1 shown necessary for CHD8 recruitment\",\n      \"pmids\": [\"36575212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"In retinal ganglion cells, Elk-1 is both necessary and sufficient for neuroprotection and axon regeneration after optic nerve injury; its activity is enhanced by specific phosphorylation site manipulation. Epistasis experiments show Elk-1 acts downstream of PTEN and is inhibited by REST in the survival/regeneration pathway.\",\n      \"method\": \"In vivo AAV-mediated Elk-1 overexpression and phosphomutant expression; optic nerve crush model; dominant-negative experiments; genetic epistasis with PTEN and REST\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo gain- and loss-of-function with pathway epistasis, single lab\",\n      \"pmids\": [\"36261683\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ERK/ELK1 signaling directs plasma cell differentiation by repressing BACH2; ELK1 controls an active regulatory region within the BACH2 super-enhancer. RNA-seq and ChIP-seq confirmed ELK1-dependent BACH2 repression in IL-2-stimulated human naive B cells.\",\n      \"method\": \"ChIP-seq for ELK1 at BACH2 super-enhancer; RNA-seq; IL-2 stimulation with ERK pathway inhibitors; BACH2 overexpression rescue\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP-seq and RNA-seq with functional rescue, multiple orthogonal approaches, novel mechanistic connection\",\n      \"pmids\": [\"29129929\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ELK-1 overexpression in mouse hippocampus produces depressive-like behaviors; selective inhibition of ELK-1 activation prevents stress-induced depression-like molecular and behavioral states. ELK-1 mRNA is upregulated in postmortem hippocampus from depressed suicides.\",\n      \"method\": \"Hippocampal ELK-1 viral overexpression; stress models in mice; ELK-1 selective inhibition; behavioral assays; molecular/synaptic plasticity readouts\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo gain- and loss-of-function with behavioral and molecular readouts, single lab, mechanistic placement downstream of ERK\",\n      \"pmids\": [\"29736027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"The lncRNA ACTA2-AS1 facilitates recruitment of the p300/ELK1 complex to the PDGFB promoter after LPS exposure in cholangiocytes; this drives p300-mediated H3K27 acetylation and transcriptional activation of proliferative/fibrogenic genes. The complex was confirmed by co-immunoprecipitation, RNA-IP, and ChIP.\",\n      \"method\": \"Co-immunoprecipitation of p300 and ELK1; RNA-IP; ChIP for p300/ELK1 occupancy and H3K27ac at PDGFB promoter; ACTA2-AS1 depletion organoids\",\n      \"journal\": \"Journal of hepatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, ChIP, and RNA-IP as orthogonal methods; mechanistic link between ELK1, p300 complex, and specific chromatin modification\",\n      \"pmids\": [\"34953958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SETD8 directly interacts with ELK1 (Co-IP and GST pulldown); ELK1 binds the bach1 promoter to activate its transcription; H4K20me1 (downstream of SETD8) co-occupies the bach1 promoter with ELK1. Mutual inhibition between SETD8 and ELK1 regulates EndMT in diabetic nephropathy.\",\n      \"method\": \"Co-immunoprecipitation; GST pulldown; ChIP for ELK1 and H4K20me1 at bach1 promoter; dual-luciferase assay with ELK1 binding site deletion\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and GST pulldown confirm SETD8-ELK1 interaction; ChIP and luciferase mutant confirm ELK1 binding at bach1 promoter; single lab\",\n      \"pmids\": [\"35351142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ERK signaling through ELK4 (SAP-1) and ELK1 in the thymus cell-autonomously suppresses innate-like αβ CD8+ T cell differentiation; mice lacking both ELK4 and ELK1 develop increased innate-like CD8+ T cells. The effect is mediated via ELK4/ELK1-SRF target genes including EGR2.\",\n      \"method\": \"ELK4 and ELK1 double-knockout mice; T cell development analysis; EGR2 overexpression rescue; ERK pathway inhibition in peripheral CD8+ T cells\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout with cell-autonomous epistasis, rescue experiment with EGR2 overexpression\",\n      \"pmids\": [\"30068599\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Elk-1 transcription factor is identified as a candidate regulator of prodromal transcriptional changes in Huntington's disease (HD); AAV-mediated Elk-1 overexpression in R6/1 mice alleviated transcriptional dysregulation. Exogenous Elk-1 expression exerted beneficial effects in primary striatal HD cell culture.\",\n      \"method\": \"Transcriptional and chromatin profiling (H3K27ac) in R6/1 mice; AAV-Elk-1 overexpression in vivo; primary striatal HD cell culture\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — integrative chromatin/transcriptional profiling and in vivo/in vitro functional validation with AAV overexpression\",\n      \"pmids\": [\"31744868\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ELK1 directly binds the BCL6 promoter and activates its transcription as part of the MAPK/ERK/ELK1 axis downstream of mutant KRAS; ChIP and reporter assays confirmed ELK1 occupancy and transcriptional regulation of BCL6.\",\n      \"method\": \"ChIP for ELK1 at BCL6 promoter; luciferase reporter assay; MEK/ERK inhibitors; ELK1 knockdown; KRAS-mutant lung cancer mouse model (LSL-KrasG12D/+)\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP and reporter assay confirm direct ELK1-BCL6 transcriptional regulation; in vivo validation with genetically engineered KRAS mouse model\",\n      \"pmids\": [\"36377663\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"ELK1 directly binds to the FADS2 promoter in an allele-specific manner at SNP rs968567; this binding was demonstrated by electrophoretic mobility shift assay, showing the minor allele abolishes ELK1 binding and reduces FADS2 promoter activity.\",\n      \"method\": \"Electrophoretic mobility shift assay (EMSA); luciferase reporter gene assays; supershift with anti-ELK1 antibody\",\n      \"journal\": \"Journal of lipid research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — EMSA with supershift and luciferase reporter, single lab, allele-specific binding established\",\n      \"pmids\": [\"19546342\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ELK1 is an ETS-domain transcription factor that is phosphorylated at Ser383 (and additional sites) by ERK, JNK/SAPK, and p38 MAP kinases, converting it from a transcriptionally repressed to an active state; it forms ternary complexes with SRF on serum response elements to drive immediate-early gene transcription (e.g., c-fos, Egr-1); its activity is negatively regulated by calcineurin-mediated dephosphorylation of Ser383 and by SUMO conjugation (at K230/249/254) which promotes nuclear retention but reduces transcriptional output, with ERK activation simultaneously removing SUMO while adding activating phosphorylation; it also uses two distinct binding modes (SRF-dependent ternary and SRF-independent unique) to control different functional gene classes including cell migration; in neurons it acts downstream of ERK/DJ-1 to regulate antioxidant and survival genes; and it cooperates with chromatin regulators (p300, CHD8, SETD8) at target promoters to drive context-specific transcriptional programmes.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ELK1 is an ETS-domain transcription factor that converts MAP kinase signalling into immediate-early and context-specific transcriptional programmes [#0, #4, #15]. Its amino-terminal ETS domain (residues 1-93) is an independently folded mixed α/β module that binds DNA with high affinity and specificity without bending it, while flanking sequences including a B-box protein-protein interaction domain mediate ternary complex formation with SRF on serum response elements [#0, #3, #6]. ELK1 is a direct substrate of ERK and stress-activated JNK/SAPK kinases, with which it physically associates; phosphorylation—notably at Ser383—activates its transcriptional output and drives target genes such as c-fos [#1, #2, #4, #20]. This activation is opposed by calcineurin (PP2B), which specifically dephosphorylates Ser383 to provide negative cross-talk between Ca2+ and MAPK signalling, and full transcriptional activation additionally requires nuclear Ca2+ downstream of phosphorylation [#7, #9]. ELK1 activity is further gated by SUMO conjugation at lysines 230/249/254, which promotes nuclear retention and dampens output; ERK activation employs a two-step mechanism that strips SUMO while adding activating phosphorylation [#11, #12]. Through two distinct DNA-binding modes—an SRF-dependent ternary mode and a unique mode at sites not bound by other ETS factors—ELK1 controls separable gene classes, including genes governing cell migration [#15]. Beyond classical immediate-early activation, ELK1 acts as a direct transcriptional repressor at promoters such as ITGB6 and smooth-muscle genes, and as an activator at promoters including GDH1, BCL6, MLCK, miR-17-92 and BACH2/BACH1, cooperating with chromatin regulators p300, CHD8 and SETD8 to execute context-specific programmes across endothelial, immune, neuronal, fibrotic and cancer settings [#13, #16, #18, #19, #20, #22, #24, #26, #27, #30]. In neurons it functions downstream of an ERK/DJ-1 axis to drive antioxidant and survival responses [#17, #23].\",\n  \"teleology\": [\n    {\n      \"year\": 1992,\n      \"claim\": \"Established the modular architecture underlying ELK1 DNA recognition, defining which domains read DNA directly versus those needed to partner with SRF.\",\n      \"evidence\": \"Domain deletion and point mutagenesis with DNA-binding and ternary complex assays\",\n      \"pmids\": [\"1630903\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve how phosphorylation alters these binding modes\", \"No structural model of the ternary complex\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Defined the ETS domain as an autonomous high-affinity DNA-binding fold that engages DNA without inducing bending, anchoring the recognition mechanism structurally.\",\n      \"evidence\": \"NMR/CD/fluorescence spectroscopy and circular-permutation bending analysis on purified ETS domain\",\n      \"pmids\": [\"7890710\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of full-length protein not determined\", \"Did not address SRF-bound conformation\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Placed ELK1 as a convergent substrate of both ERK and stress-activated JNK/SAPK pathways, explaining how distinct stimuli feed the same factor.\",\n      \"evidence\": \"In vitro kinase assays with purified SAPK/ERK and Elk-1, plus cell-based phosphorylation and c-fos readouts\",\n      \"pmids\": [\"7651411\", \"8339245\", \"8208531\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of each kinase in vivo unresolved\", \"Full set of phosphoacceptor sites not enumerated here\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Identified upstream signalling architecture (cAMP/Rap1/B-Raf) feeding ELK1 activation and showed it links to neuronal differentiation, establishing cell-type-specific routing into ELK1.\",\n      \"evidence\": \"PC12 transfection with dominant-negative/activated mutants and Elk-1 reporter assays\",\n      \"pmids\": [\"9094716\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify direct ELK1 target genes for differentiation\", \"Mechanism of B-Raf vs Raf-1 selectivity on ELK1 output unaddressed\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Showed ELK1 activity is reversibly controlled at a single critical residue, with calcineurin dephosphorylating Ser383 to integrate Ca2+ with MAPK input.\",\n      \"evidence\": \"Constitutively active calcineurin cotransfection, Ca2+ ionophore, phospho-Ser383 Western and c-fos reporter; brain-slice glutamate/ERK studies\",\n      \"pmids\": [\"10329725\", \"9858538\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Other phosphosites' regulation by phosphatases not mapped\", \"Specificity of calcineurin for ELK1 in vivo incompletely defined\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Revealed that ELK1 phosphorylation is necessary but not sufficient, with nuclear Ca2+ required downstream for full transactivation, and that menin can uncouple ERK activity from ELK1 phosphorylation.\",\n      \"evidence\": \"Compartment-targeted parvalbumin with GAL4-Elk-1 reporter; menin overexpression with kinase and reporter assays\",\n      \"pmids\": [\"11971908\", \"12226747\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Nuclear Ca2+ effector acting on ELK1 not identified\", \"Mechanism by which menin blocks phosphorylation unresolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Defined SUMOylation as a second, antagonistic layer of control, with ERK simultaneously removing SUMO and adding activating phosphorylation in a two-step activation switch.\",\n      \"evidence\": \"In vitro/in vivo SUMOylation assays, triple-lysine mutant, heterokaryon export and PC12 neurite assays; PIASx-alpha co-activator model\",\n      \"pmids\": [\"15210726\", \"16626293\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Symposium synthesis (idx 12) builds on primary data\", \"Deconjugating enzyme and kinetics of SUMO removal not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Genome-wide mapping resolved that ELK1 uses two binding modes—redundant ETS sites and unique sites—to control separable gene programmes including cell migration.\",\n      \"evidence\": \"ChIP-seq with loss-of-function, migration assays and expression profiling\",\n      \"pmids\": [\"22589737\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Determinants directing ELK1 to unique vs redundant sites unknown\", \"Cofactor differences between the two modes not defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Showed ELK1 functions as a direct repressor as well as activator across tissues—repressing BACH2 in B cells, ITGB6 in fibrosis, and smooth-muscle genes—broadening its role beyond immediate-early activation.\",\n      \"evidence\": \"ChIP/ChIP-seq, reporter mutagenesis, knockdown and Elk1-knockout mouse models with disease phenotypes\",\n      \"pmids\": [\"29129929\", \"26861876\", \"16260603\", \"30068599\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Switch between activator and repressor functions mechanistically unexplained\", \"Corepressor identity at repressed promoters not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Established ELK1 as a recruiter of chromatin machinery, showing it is required to bring CHD8, p300 and SETD8/H4K20me1 to specific promoters to execute context-specific transcription.\",\n      \"evidence\": \"ATAC-seq, ChIP, Co-IP, GST pulldown and RNA-IP in neurons, cholangiocytes and EndMT models\",\n      \"pmids\": [\"36575212\", \"34953958\", \"35351142\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect nature of some chromatin-factor interactions not fully resolved\", \"Whether recruitment depends on ELK1 phosphorylation state untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed ELK1 as a transcriptional effector of oncogenic and metabolic programmes (GDH1 glutaminolysis, BCL6 downstream of mutant KRAS) and of neuroprotection/regeneration via an ERK/DJ-1/SOD1 axis.\",\n      \"evidence\": \"ChIP, Ser383 point mutation, metabolic assays, KRAS-mutant and optic-nerve-crush in vivo models; DJ-1 Co-IP and knockout\",\n      \"pmids\": [\"32034306\", \"36377663\", \"21796667\", \"36261683\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Selectivity of these target promoters across cell types unexplained\", \"How upstream pathway choice dictates ELK1 target repertoire unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved what molecular determinants dictate whether ELK1 activates or represses a given promoter and which cofactor it engages, i.e. how a single MAPK-driven factor is routed into divergent context-specific programmes.\",\n      \"evidence\": \"No timeline study reconciles the activator/repressor and unique/redundant binding-mode logic mechanistically\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying model linking phosphorylation/SUMO state to activator vs repressor outcome\", \"Cofactor selection rules undefined\", \"No structure of ELK1 in complex with chromatin regulators\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 13, 15, 16, 18, 20, 24, 30]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0, 3, 31]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [11, 16]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 5, 7, 20]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 6, 15, 24, 30]}\n    ],\n    \"complexes\": [\n      \"ELK1-SRF ternary complex\"\n    ],\n    \"partners\": [\n      \"SRF\",\n      \"ERK2\",\n      \"SAP1a\",\n      \"p300\",\n      \"CHD8\",\n      \"SETD8\",\n      \"PIAS1\",\n      \"PARP1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}