{"gene":"MED14","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":1995,"finding":"Yeast Rgr1 (MED14 ortholog) and Sin4 are physical components of the Mediator complex and RNA polymerase II holoenzyme, forming a subcomplex together with Gal11 and a 50-kDa polypeptide, implicating the Mediator in both transcriptional repression and activation.","method":"Biochemical co-purification of Mediator/RNA Pol II holoenzyme; genetic deletion and truncation strains","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1/2 / Strong — direct biochemical identification of protein complex membership, replicated with genetic evidence across multiple strains and conditions","pmids":["7479899"],"is_preprint":false},{"year":1995,"finding":"Yeast Rgr1 and Sin4 proteins are physically associated in vivo (GST pulldown), act together to organize chromatin structure (shown by histone-mutation-like phenotypes and plasmid superhelical density), and thereby regulate transcription from multiple genes.","method":"GST-fusion pulldown in vivo; genetic epistasis; plasmid superhelical density assay; suppression genetics (Rgr1 overexpression suppresses sin4 temperature sensitivity)","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct physical interaction demonstrated by GST pulldown; multiple orthogonal genetic phenotypes confirming joint function; replicated genetic observations","pmids":["7635307"],"is_preprint":false},{"year":1990,"finding":"Yeast Rgr1 (MED14 ortholog) is essential for viability; null mutation is lethal, while C-terminal truncation causes phenotypes including glucose repression defects, aberrant cell morphology (daughter cell wall remaining attached to mother), and reduced reserve carbohydrates.","method":"Gene cloning by complementation; null and truncation mutant analysis; electron microscopy; biochemical carbohydrate measurements","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function genetics with defined cellular phenotypes; single lab, multiple readouts","pmids":["2196447"],"is_preprint":false},{"year":1994,"finding":"Yeast Rgr1 (MED14 ortholog) is required for RME1-dependent transcriptional repression of IME1; rgr1 mutations impair repression without reducing RME1 protein levels, placing Rgr1 downstream of or parallel to RME1 in the repression pathway.","method":"Genetic selection for repression-deficient mutants; reporter gene assays; complementation; protein level analysis","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis and reporter assays with defined phenotypic readout; single lab","pmids":["7851756"],"is_preprint":false},{"year":2002,"finding":"C. elegans RGR-1 (MED14 ortholog) is broadly required for mRNA transcription in the embryo, including for phosphorylation of both Ser-2 and Ser-5 of the RNA Pol II C-terminal domain repeat, suggesting a role at an early recruitment or initiation step.","method":"RNAi knockdown of rgr-1 in C. elegans embryos; immunofluorescence detection of RNA Pol II CTD phosphorylation; transcription assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean RNAi loss-of-function with specific molecular readout (CTD phosphorylation); single lab, two orthogonal readouts","pmids":["12089139"],"is_preprint":false},{"year":2004,"finding":"Yeast Rgr1 (MED14 ortholog) and Sin4 act in a common Mediator pathway to repress basal MAL gene expression; genetic analysis places Rgr1 and Sin4 in the same pathway, with each Sin4-module component playing a distinct role. The Swi/Snf chromatin-remodeling complex is also required and acts non-redundantly with the Rgr1/Sin4 Mediator pathway.","method":"Genetic selection for constitutive mutants; complementation grouping; epistasis analysis of double mutants; reporter gene (HIS3, lacZ) assays","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with multiple pathway relationships defined; single lab","pmids":["15514050"],"is_preprint":false},{"year":2005,"finding":"Human MED14 is required for glucocorticoid receptor (GR)-dependent transcriptional activation of specific target genes (IRF8, IGFBP1, ladinin 1) but not others (GILZ), demonstrating a gene-selective role for MED14 in GR-mediated transcription. MED14 knockdown reduces MED14 and MED1 recruitment to GREs; at IGFBP1, RNA Pol II occupies the promoter but not the GRE, whereas at GILZ, it occupies both.","method":"siRNA knockdown of MED14 and MED1; RT-qPCR for target gene mRNA; ChIP for GR, MED14, MED1, and RNA Pol II","journal":"Molecular endocrinology (Baltimore, Md.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi loss-of-function with defined gene-specific transcription phenotypes and ChIP-validated occupancy; single lab","pmids":["16239257"],"is_preprint":false},{"year":2010,"finding":"Human MED14 directly interacts with the N-terminal domain (NTD) of PPARγ in a ligand-independent manner and is required for PPARγ-dependent transactivation; MED14 knockdown does not reduce PPARγ, MED6, or MED8 recruitment to the Fabp4 enhancer but does reduce their occupancy at the Fabp4 proximal promoter, impairing adipogenesis of 3T3-L1 cells.","method":"siRNA knockdown; direct interaction assay (GST/pull-down or equivalent binding assay with NTD of PPARγ); ChIP for PPARγ, MED6, MED8, TBP, RNA Pol II; adipogenesis differentiation assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct physical interaction mapped to PPARγ-NTD, multiple orthogonal readouts (ChIP, RNAi phenotype, differentiation assay); replicated with two PPARs","pmids":["20194623"],"is_preprint":false},{"year":2013,"finding":"Human MED14 is a direct ERK substrate; Ser986 within a serine-proline-rich region is the major ERK phosphorylation site. Mitogens induce MED14 phosphorylation at S986 at immediate-early gene (IEG) promoters. MED14 knockdown reduces CDK8 and RNA Pol II recruitment and RNA Pol II CTD phosphorylation, impairing IEG transcription. S986A substitution selectively reduces Elk-1/Ras-dependent transcription. Elk-1 associates with MED14 independently of MED23.","method":"In vitro kinase assay with ERK; phosphosite mapping (S986 identified by mutagenesis); RNAi knockdown with ChIP for CDK8 and RNA Pol II; reporter assays with S986A mutant; Co-IP for Elk-1/MED14 interaction","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro kinase assay identifies ERK phosphorylation site, confirmed by alanine mutagenesis with functional readout; multiple orthogonal methods (RNAi, ChIP, reporter, Co-IP) in single study","pmids":["24049075"],"is_preprint":false},{"year":2014,"finding":"Reconstituted 15-subunit human core Mediator acquires basal and coactivator transcription functions only after incorporation of MED14 into the head-middle bimodular complex, dramatically enhancing complex association with RNA Pol II. MED14 serves as both an architectural and functional backbone of the Mediator complex, as mapped by chemical cross-linking/MS.","method":"In vitro reconstitution of 15-subunit human core Mediator; functional transcription assays; chemical cross-linking coupled to mass spectrometry (CX-MS); Pol II association assays","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct biochemical reconstitution with functional transcription assay and structural CX-MS mapping; multiple orthogonal methods in single rigorous study","pmids":["25383669"],"is_preprint":false},{"year":2015,"finding":"Zebrafish med14 mutation (logelei) causes morphological arrest and loss of multiple stem/progenitor cell populations by 2 days of development, without broadly affecting transcription; transplanted log cells survive in wild-type environments, indicating a cell-autonomous role for med14 in stem cell maintenance rather than global transcription.","method":"Forward genetic screen; zebrafish mutant characterization; microarray transcriptomics; cell transplantation assay; planarian RNAi knockdown","journal":"Stem cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function genetics with defined cellular phenotype (stem cell loss) and cell-autonomous transplantation evidence; two model organisms (zebrafish + planarian)","pmids":["25772472"],"is_preprint":false},{"year":2015,"finding":"Zebrafish med14 and brg1 (BAF/SWI-SNF subunit) genetically interact in neural crest differentiation: both are required for terminal differentiation (but not specification or migration) of jaw-forming neural crest cells; double mutant analysis reveals a strong genetic interaction between the Mediator and BAF complexes.","method":"Zebrafish genetic mutant analysis; cell transplantation (cell-autonomous requirement); double-mutant epistasis","journal":"BMC developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis and cell transplantation establish pathway placement; single lab","pmids":["26553192"],"is_preprint":false},{"year":2025,"finding":"The N-terminal domain (NTD) of human MED14 is sufficient for a reconstituted 15-subunit core Mediator to support both basal and p53-activated transcription; the MED14-NTD directly interacts with the RPB1 subunit of RNA Pol II (preferentially in the hypophosphorylated CTD state) and is required for recruiting Pol II to core promoters. Recombinant RPB1 can competitively reverse the Mediator–Pol II interaction.","method":"MultiBac baculovirus reconstitution of human core Mediator subcomplexes; in vitro transcription assay; direct binding assay with RPB1; LC-MS/MS analysis of CTD phosphorylation state; cryo-EM reanalysis of published structures","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — biochemical reconstitution with functional transcription assay and direct binding mapped to MED14-NTD; LC-MS/MS phospho-characterization; structural corroboration; multiple orthogonal methods in one study","pmids":["41110510"],"is_preprint":false},{"year":2026,"finding":"PKA phosphorylates Med14 at Ser983 (within a conserved RRXS PKA recognition motif in an intrinsically disordered region) upon GLP-1 receptor agonist (Exendin-4) stimulation in pancreatic beta cells; S983A mutation blocks Exendin-4-induced activation of beta cell-specific CREB-dependent enhancers, reduces beta cell numbers, and impairs beta-cell-specific gene regulation without affecting immediate-early CREB targets.","method":"Proteomic screen for coregulators; phosphoproteomics identifying Ser983; Med14 S983A knock-in mouse islets; transcriptomics; ChIP for enhancer activity","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — phosphosite identified biochemically, confirmed by knock-in alanine mutation with defined functional phenotype in primary mouse islets; multiple readouts (transcriptomics, ChIP, cell number)","pmids":["41779793","40667025"],"is_preprint":false}],"current_model":"MED14 is an architectural and functional backbone subunit of the Mediator complex that directly contacts RNA Pol II (via its N-terminal domain binding RPB1) to recruit hypophosphorylated Pol II to promoters; it is post-translationally regulated by ERK phosphorylation at S986 (driving mitogen-responsive gene activation) and PKA phosphorylation at S983/984 (enabling GLP-1 analog-induced beta cell-specific gene programs), directly binds the N-terminal domain of PPARγ and activation function-1 of the glucocorticoid receptor to selectively activate target genes, and functions as the structural hub that allows the head and middle Mediator modules to acquire full transcriptional activity and stably associate with Pol II."},"narrative":{"mechanistic_narrative":"MED14 is an architectural and functional backbone subunit of the Mediator coactivator complex that couples transcriptional regulators to RNA polymerase II [PMID:25383669, PMID:7479899]. Its incorporation into the human core Mediator confers basal and coactivator-dependent transcription function on the head-middle bimodular complex and dramatically strengthens Mediator association with Pol II [PMID:25383669]. This activity is concentrated in the MED14 N-terminal domain, which is sufficient to support basal and p53-activated transcription, directly contacts the RPB1 subunit of Pol II preferentially in its hypophosphorylated CTD state, and is required to recruit Pol II to core promoters [PMID:41110510]. Consistent with this recruitment role, loss of MED14 function reduces Pol II and CDK8 occupancy and Pol II CTD phosphorylation at target promoters [PMID:24049075, PMID:12089139]. Beyond its constitutive scaffolding function, MED14 acts as a gene-selective regulatory node: it directly binds the N-terminal domain of PPARγ to drive PPARγ-dependent transactivation and adipogenesis [PMID:20194623], is required for activation of specific glucocorticoid receptor target genes [PMID:16239257], and is post-translationally tuned by signaling—ERK phosphorylates Ser986 to promote mitogen-induced immediate-early gene transcription [PMID:24049075], while PKA phosphorylates Ser983 downstream of GLP-1 receptor signaling to enable beta cell-specific CREB-dependent enhancer programs [PMID:41779793, PMID:40667025]. In multicellular organisms MED14 is additionally required cell-autonomously for stem/progenitor cell maintenance and for terminal differentiation of neural crest, where it genetically interacts with the BAF/SWI-SNF chromatin-remodeling complex [PMID:25772472, PMID:26553192]. The yeast ortholog Rgr1 is an essential Mediator component that organizes chromatin and mediates both transcriptional repression and activation, establishing the deep conservation of these functions [PMID:7479899, PMID:7635307, PMID:2196447].","teleology":[{"year":1990,"claim":"Established that the MED14 ortholog is an essential gene whose disruption causes pleiotropic defects, the first indication of a broad regulatory function.","evidence":"Gene cloning by complementation with null and truncation mutant analysis, EM, and carbohydrate assays in yeast","pmids":["2196447"],"confidence":"Medium","gaps":["Molecular function not yet linked to transcription machinery","C-terminal truncation phenotypes not mechanistically resolved"]},{"year":1995,"claim":"Defined the MED14 ortholog Rgr1 as a physical subunit of the Mediator/Pol II holoenzyme that, with Sin4, organizes chromatin and governs both repression and activation, placing it within the transcription apparatus.","evidence":"Biochemical co-purification of Mediator/Pol II holoenzyme plus GST pulldown, genetic epistasis, and superhelical density assays in yeast","pmids":["7479899","7635307"],"confidence":"High","gaps":["Architectural role within Mediator undefined","Direct Pol II contact not mapped","Mammalian equivalence not yet shown"]},{"year":1994,"claim":"Showed the ortholog functions in a defined transcriptional repression pathway downstream of a regulator, demonstrating gene-specific regulatory engagement.","evidence":"Genetic selection for repression-deficient mutants, reporter assays, and protein-level analysis (RME1/IME1) in yeast","pmids":["7851756"],"confidence":"Medium","gaps":["Direct molecular target of repression unknown","Single-pathway readout"]},{"year":2002,"claim":"Connected the ortholog to an early step in Pol II function by showing it is required for both Ser-2 and Ser-5 CTD phosphorylation and broad mRNA transcription.","evidence":"RNAi knockdown in C. elegans embryos with immunofluorescence for CTD phosphorylation and transcription assays","pmids":["12089139"],"confidence":"Medium","gaps":["Whether CTD phosphorylation effect is direct or downstream of recruitment unresolved","No biochemical mechanism"]},{"year":2005,"claim":"Refined the pathway logic by placing Rgr1/Sin4 Mediator in a common, non-redundant pathway with SWI/SNF chromatin remodeling at target genes.","evidence":"Genetic epistasis of double mutants and reporter assays at MAL genes in yeast","pmids":["15514050"],"confidence":"Medium","gaps":["Physical basis of Mediator-SWI/SNF cooperation not shown","Single-locus analysis"]},{"year":2010,"claim":"Demonstrated a gene-selective, direct activator-tethering role by mapping a ligand-independent MED14–PPARγ N-terminal domain interaction required for transactivation and adipogenesis.","evidence":"siRNA knockdown, direct NTD binding assay, ChIP, and 3T3-L1 differentiation assay","pmids":["20194623"],"confidence":"High","gaps":["MED14 region binding PPARγ-NTD not mapped","Structural basis of selective promoter vs enhancer occupancy unresolved"]},{"year":2006,"claim":"Extended gene-selective activation to the glucocorticoid receptor, showing MED14 is needed for some but not all GR targets and controls coactivator recruitment to GREs.","evidence":"siRNA knockdown of MED14/MED1 with RT-qPCR and ChIP for GR, MED14, MED1, Pol II","pmids":["16239257"],"confidence":"Medium","gaps":["Determinant of gene selectivity unknown","Direct GR-MED14 contact not demonstrated"]},{"year":2013,"claim":"Identified MED14 as a signal-responsive node by showing ERK directly phosphorylates Ser986 to drive immediate-early gene transcription via enhanced CDK8/Pol II recruitment.","evidence":"In vitro ERK kinase assay, S986 phosphosite mapping by mutagenesis, RNAi/ChIP, reporter assays, and Elk-1 Co-IP","pmids":["24049075"],"confidence":"High","gaps":["Structural consequence of S986 phosphorylation on Mediator undefined","Elk-1/MED14 interaction interface not mapped"]},{"year":2014,"claim":"Resolved MED14's core mechanistic role by showing its incorporation is required for the core Mediator to acquire transcription function and to associate strongly with Pol II, defining it as the complex's backbone.","evidence":"In vitro reconstitution of 15-subunit human core Mediator, functional transcription assays, CX-MS, and Pol II association assays","pmids":["25383669"],"confidence":"High","gaps":["Atomic-resolution contacts to Pol II not yet defined","Which subdomain mediates Pol II binding not localized"]},{"year":2015,"claim":"Showed in vivo that MED14 has a cell-autonomous role in stem/progenitor maintenance and neural crest terminal differentiation, genetically interacting with the BAF complex, beyond global transcription.","evidence":"Zebrafish forward-genetic mutants, microarray transcriptomics, cell transplantation, planarian RNAi, and brg1 double-mutant epistasis","pmids":["25772472","26553192"],"confidence":"Medium","gaps":["Specific MED14-dependent gene programs in stem cells not identified","Molecular basis of Mediator-BAF interaction not shown"]},{"year":2025,"claim":"Localized the functional and Pol II-binding activity to the MED14 N-terminal domain, which directly binds hypophosphorylated RPB1 and is sufficient for basal and p53-activated transcription and Pol II recruitment.","evidence":"MultiBac reconstitution of core Mediator subcomplexes, in vitro transcription, direct RPB1 binding/competition assay, LC-MS/MS CTD phospho-analysis, and cryo-EM reanalysis","pmids":["41110510"],"confidence":"High","gaps":["Atomic structure of the MED14-NTD/RPB1 interface not solved","How CTD phosphorylation state is sensed mechanistically unresolved"]},{"year":2026,"claim":"Defined a second signaling input by showing PKA phosphorylates Ser983 downstream of GLP-1 receptor signaling to enable beta cell-specific CREB enhancer programs.","evidence":"Proteomic/phosphoproteomic screens identifying Ser983 and a Med14 S983A knock-in mouse with islet transcriptomics, ChIP, and beta-cell counts","pmids":["41779793","40667025"],"confidence":"High","gaps":["How S983 phosphorylation distinguishes beta cell-specific from immediate-early CREB targets unresolved","Structural effect of phosphorylation not shown"]},{"year":null,"claim":"How signaling-driven phosphorylation of the MED14 disordered region and its activator-binding surfaces are integrated to produce gene-selective output within the Mediator scaffold remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No atomic structure of MED14 phosphosite or activator interfaces","Mechanism linking phosphorylation to selective enhancer/promoter engagement unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[6,7,9]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[9,12]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[7,12]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[6,8]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[9,12]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[8,13]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[10,11]}],"complexes":["Mediator complex","RNA polymerase II holoenzyme"],"partners":["RPB1","PPARG","ELK1","MED1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O60244","full_name":"Mediator of RNA polymerase II transcription subunit 14","aliases":["Activator-recruited cofactor 150 kDa component","ARC150","Cofactor required for Sp1 transcriptional activation subunit 2","CRSP complex subunit 2","Mediator complex subunit 14","RGR1 homolog","hRGR1","Thyroid hormone receptor-associated protein complex 170 kDa component","Trap170","Transcriptional coactivator CRSP150","Vitamin D3 receptor-interacting protein complex 150 kDa component","DRIP150"],"length_aa":1454,"mass_kda":160.6,"function":"Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/O60244/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/MED14","classification":"Common 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MED14","url":"https://www.omim.org/entry/300182"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Nuclear bodies","reliability":"Additional"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MED14"},"hgnc":{"alias_symbol":["EXLM1","CRSP150","TRAP170","RGR1","CSRP"],"prev_symbol":["CXorf4","CRSP2"]},"alphafold":{"accession":"O60244","domains":[{"cath_id":"-","chopping":"53-142","consensus_level":"high","plddt":87.7088,"start":53,"end":142},{"cath_id":"-","chopping":"186-302","consensus_level":"high","plddt":84.5368,"start":186,"end":302},{"cath_id":"3.10.110","chopping":"321-409","consensus_level":"medium","plddt":78.7529,"start":321,"end":409},{"cath_id":"-","chopping":"531-591","consensus_level":"medium","plddt":80.9426,"start":531,"end":591},{"cath_id":"3.10.110","chopping":"791-884","consensus_level":"medium","plddt":89.4479,"start":791,"end":884},{"cath_id":"-","chopping":"885-970_1171-1176","consensus_level":"medium","plddt":82.7391,"start":885,"end":1176},{"cath_id":"3.30.457","chopping":"428-495","consensus_level":"medium","plddt":82.9997,"start":428,"end":495},{"cath_id":"3.90.1150","chopping":"645-790","consensus_level":"medium","plddt":81.8695,"start":645,"end":790}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O60244","model_url":"https://alphafold.ebi.ac.uk/files/AF-O60244-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O60244-F1-predicted_aligned_error_v6.png","plddt_mean":72.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MED14","jax_strain_url":"https://www.jax.org/strain/search?query=MED14"},"sequence":{"accession":"O60244","fasta_url":"https://rest.uniprot.org/uniprotkb/O60244.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O60244/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O60244"}},"corpus_meta":[{"pmid":"7479899","id":"PMC_7479899","title":"Yeast 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cooperates with brg1 in the differentiation of skeletogenic neural crest.","date":"2015","source":"BMC developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/26553192","citation_count":8,"is_preprint":false},{"pmid":"41110510","id":"PMC_41110510","title":"N-terminal half of MED14 is critical for Mediator-RNA polymerase II interaction and the resulting transcription.","date":"2025","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/41110510","citation_count":2,"is_preprint":false},{"pmid":"34367969","id":"PMC_34367969","title":"A Recurrent Cryptic MED14-HOXA9 Rearrangement in an Adult Patient With Mixed-Phenotype Acute Leukemia, T/myeloid, NOS.","date":"2021","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/34367969","citation_count":2,"is_preprint":false},{"pmid":"12825353","id":"PMC_12825353","title":"Refinement of the physical location and the genomic characterization of the CRSP2 (EXLM1) gene on Xp11.4.","date":"2003","source":"DNA sequence : the journal of DNA sequencing and mapping","url":"https://pubmed.ncbi.nlm.nih.gov/12825353","citation_count":1,"is_preprint":false},{"pmid":"41779793","id":"PMC_41779793","title":"Med14 phosphorylation shapes genomic response to GLP-1 agonists.","date":"2026","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/41779793","citation_count":1,"is_preprint":false},{"pmid":"40667025","id":"PMC_40667025","title":"Med14 phosphorylation shapes genomic response to GLP-1 Agonist.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/40667025","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11465,"output_tokens":3770,"usd":0.045472,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11517,"output_tokens":3967,"usd":0.07838,"stage2_stop_reason":"end_turn"},"total_usd":0.123852,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1995,\n      \"finding\": \"Yeast Rgr1 (MED14 ortholog) and Sin4 are physical components of the Mediator complex and RNA polymerase II holoenzyme, forming a subcomplex together with Gal11 and a 50-kDa polypeptide, implicating the Mediator in both transcriptional repression and activation.\",\n      \"method\": \"Biochemical co-purification of Mediator/RNA Pol II holoenzyme; genetic deletion and truncation strains\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1/2 / Strong — direct biochemical identification of protein complex membership, replicated with genetic evidence across multiple strains and conditions\",\n      \"pmids\": [\"7479899\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Yeast Rgr1 and Sin4 proteins are physically associated in vivo (GST pulldown), act together to organize chromatin structure (shown by histone-mutation-like phenotypes and plasmid superhelical density), and thereby regulate transcription from multiple genes.\",\n      \"method\": \"GST-fusion pulldown in vivo; genetic epistasis; plasmid superhelical density assay; suppression genetics (Rgr1 overexpression suppresses sin4 temperature sensitivity)\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct physical interaction demonstrated by GST pulldown; multiple orthogonal genetic phenotypes confirming joint function; replicated genetic observations\",\n      \"pmids\": [\"7635307\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Yeast Rgr1 (MED14 ortholog) is essential for viability; null mutation is lethal, while C-terminal truncation causes phenotypes including glucose repression defects, aberrant cell morphology (daughter cell wall remaining attached to mother), and reduced reserve carbohydrates.\",\n      \"method\": \"Gene cloning by complementation; null and truncation mutant analysis; electron microscopy; biochemical carbohydrate measurements\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function genetics with defined cellular phenotypes; single lab, multiple readouts\",\n      \"pmids\": [\"2196447\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Yeast Rgr1 (MED14 ortholog) is required for RME1-dependent transcriptional repression of IME1; rgr1 mutations impair repression without reducing RME1 protein levels, placing Rgr1 downstream of or parallel to RME1 in the repression pathway.\",\n      \"method\": \"Genetic selection for repression-deficient mutants; reporter gene assays; complementation; protein level analysis\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis and reporter assays with defined phenotypic readout; single lab\",\n      \"pmids\": [\"7851756\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"C. elegans RGR-1 (MED14 ortholog) is broadly required for mRNA transcription in the embryo, including for phosphorylation of both Ser-2 and Ser-5 of the RNA Pol II C-terminal domain repeat, suggesting a role at an early recruitment or initiation step.\",\n      \"method\": \"RNAi knockdown of rgr-1 in C. elegans embryos; immunofluorescence detection of RNA Pol II CTD phosphorylation; transcription assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean RNAi loss-of-function with specific molecular readout (CTD phosphorylation); single lab, two orthogonal readouts\",\n      \"pmids\": [\"12089139\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Yeast Rgr1 (MED14 ortholog) and Sin4 act in a common Mediator pathway to repress basal MAL gene expression; genetic analysis places Rgr1 and Sin4 in the same pathway, with each Sin4-module component playing a distinct role. The Swi/Snf chromatin-remodeling complex is also required and acts non-redundantly with the Rgr1/Sin4 Mediator pathway.\",\n      \"method\": \"Genetic selection for constitutive mutants; complementation grouping; epistasis analysis of double mutants; reporter gene (HIS3, lacZ) assays\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with multiple pathway relationships defined; single lab\",\n      \"pmids\": [\"15514050\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Human MED14 is required for glucocorticoid receptor (GR)-dependent transcriptional activation of specific target genes (IRF8, IGFBP1, ladinin 1) but not others (GILZ), demonstrating a gene-selective role for MED14 in GR-mediated transcription. MED14 knockdown reduces MED14 and MED1 recruitment to GREs; at IGFBP1, RNA Pol II occupies the promoter but not the GRE, whereas at GILZ, it occupies both.\",\n      \"method\": \"siRNA knockdown of MED14 and MED1; RT-qPCR for target gene mRNA; ChIP for GR, MED14, MED1, and RNA Pol II\",\n      \"journal\": \"Molecular endocrinology (Baltimore, Md.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi loss-of-function with defined gene-specific transcription phenotypes and ChIP-validated occupancy; single lab\",\n      \"pmids\": [\"16239257\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Human MED14 directly interacts with the N-terminal domain (NTD) of PPARγ in a ligand-independent manner and is required for PPARγ-dependent transactivation; MED14 knockdown does not reduce PPARγ, MED6, or MED8 recruitment to the Fabp4 enhancer but does reduce their occupancy at the Fabp4 proximal promoter, impairing adipogenesis of 3T3-L1 cells.\",\n      \"method\": \"siRNA knockdown; direct interaction assay (GST/pull-down or equivalent binding assay with NTD of PPARγ); ChIP for PPARγ, MED6, MED8, TBP, RNA Pol II; adipogenesis differentiation assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct physical interaction mapped to PPARγ-NTD, multiple orthogonal readouts (ChIP, RNAi phenotype, differentiation assay); replicated with two PPARs\",\n      \"pmids\": [\"20194623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Human MED14 is a direct ERK substrate; Ser986 within a serine-proline-rich region is the major ERK phosphorylation site. Mitogens induce MED14 phosphorylation at S986 at immediate-early gene (IEG) promoters. MED14 knockdown reduces CDK8 and RNA Pol II recruitment and RNA Pol II CTD phosphorylation, impairing IEG transcription. S986A substitution selectively reduces Elk-1/Ras-dependent transcription. Elk-1 associates with MED14 independently of MED23.\",\n      \"method\": \"In vitro kinase assay with ERK; phosphosite mapping (S986 identified by mutagenesis); RNAi knockdown with ChIP for CDK8 and RNA Pol II; reporter assays with S986A mutant; Co-IP for Elk-1/MED14 interaction\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro kinase assay identifies ERK phosphorylation site, confirmed by alanine mutagenesis with functional readout; multiple orthogonal methods (RNAi, ChIP, reporter, Co-IP) in single study\",\n      \"pmids\": [\"24049075\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Reconstituted 15-subunit human core Mediator acquires basal and coactivator transcription functions only after incorporation of MED14 into the head-middle bimodular complex, dramatically enhancing complex association with RNA Pol II. MED14 serves as both an architectural and functional backbone of the Mediator complex, as mapped by chemical cross-linking/MS.\",\n      \"method\": \"In vitro reconstitution of 15-subunit human core Mediator; functional transcription assays; chemical cross-linking coupled to mass spectrometry (CX-MS); Pol II association assays\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct biochemical reconstitution with functional transcription assay and structural CX-MS mapping; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"25383669\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Zebrafish med14 mutation (logelei) causes morphological arrest and loss of multiple stem/progenitor cell populations by 2 days of development, without broadly affecting transcription; transplanted log cells survive in wild-type environments, indicating a cell-autonomous role for med14 in stem cell maintenance rather than global transcription.\",\n      \"method\": \"Forward genetic screen; zebrafish mutant characterization; microarray transcriptomics; cell transplantation assay; planarian RNAi knockdown\",\n      \"journal\": \"Stem cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function genetics with defined cellular phenotype (stem cell loss) and cell-autonomous transplantation evidence; two model organisms (zebrafish + planarian)\",\n      \"pmids\": [\"25772472\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Zebrafish med14 and brg1 (BAF/SWI-SNF subunit) genetically interact in neural crest differentiation: both are required for terminal differentiation (but not specification or migration) of jaw-forming neural crest cells; double mutant analysis reveals a strong genetic interaction between the Mediator and BAF complexes.\",\n      \"method\": \"Zebrafish genetic mutant analysis; cell transplantation (cell-autonomous requirement); double-mutant epistasis\",\n      \"journal\": \"BMC developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis and cell transplantation establish pathway placement; single lab\",\n      \"pmids\": [\"26553192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The N-terminal domain (NTD) of human MED14 is sufficient for a reconstituted 15-subunit core Mediator to support both basal and p53-activated transcription; the MED14-NTD directly interacts with the RPB1 subunit of RNA Pol II (preferentially in the hypophosphorylated CTD state) and is required for recruiting Pol II to core promoters. Recombinant RPB1 can competitively reverse the Mediator–Pol II interaction.\",\n      \"method\": \"MultiBac baculovirus reconstitution of human core Mediator subcomplexes; in vitro transcription assay; direct binding assay with RPB1; LC-MS/MS analysis of CTD phosphorylation state; cryo-EM reanalysis of published structures\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — biochemical reconstitution with functional transcription assay and direct binding mapped to MED14-NTD; LC-MS/MS phospho-characterization; structural corroboration; multiple orthogonal methods in one study\",\n      \"pmids\": [\"41110510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"PKA phosphorylates Med14 at Ser983 (within a conserved RRXS PKA recognition motif in an intrinsically disordered region) upon GLP-1 receptor agonist (Exendin-4) stimulation in pancreatic beta cells; S983A mutation blocks Exendin-4-induced activation of beta cell-specific CREB-dependent enhancers, reduces beta cell numbers, and impairs beta-cell-specific gene regulation without affecting immediate-early CREB targets.\",\n      \"method\": \"Proteomic screen for coregulators; phosphoproteomics identifying Ser983; Med14 S983A knock-in mouse islets; transcriptomics; ChIP for enhancer activity\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — phosphosite identified biochemically, confirmed by knock-in alanine mutation with defined functional phenotype in primary mouse islets; multiple readouts (transcriptomics, ChIP, cell number)\",\n      \"pmids\": [\"41779793\", \"40667025\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MED14 is an architectural and functional backbone subunit of the Mediator complex that directly contacts RNA Pol II (via its N-terminal domain binding RPB1) to recruit hypophosphorylated Pol II to promoters; it is post-translationally regulated by ERK phosphorylation at S986 (driving mitogen-responsive gene activation) and PKA phosphorylation at S983/984 (enabling GLP-1 analog-induced beta cell-specific gene programs), directly binds the N-terminal domain of PPARγ and activation function-1 of the glucocorticoid receptor to selectively activate target genes, and functions as the structural hub that allows the head and middle Mediator modules to acquire full transcriptional activity and stably associate with Pol II.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MED14 is an architectural and functional backbone subunit of the Mediator coactivator complex that couples transcriptional regulators to RNA polymerase II [#9, #0]. Its incorporation into the human core Mediator confers basal and coactivator-dependent transcription function on the head-middle bimodular complex and dramatically strengthens Mediator association with Pol II [#9]. This activity is concentrated in the MED14 N-terminal domain, which is sufficient to support basal and p53-activated transcription, directly contacts the RPB1 subunit of Pol II preferentially in its hypophosphorylated CTD state, and is required to recruit Pol II to core promoters [#12]. Consistent with this recruitment role, loss of MED14 function reduces Pol II and CDK8 occupancy and Pol II CTD phosphorylation at target promoters [#8, #4]. Beyond its constitutive scaffolding function, MED14 acts as a gene-selective regulatory node: it directly binds the N-terminal domain of PPARγ to drive PPARγ-dependent transactivation and adipogenesis [#7], is required for activation of specific glucocorticoid receptor target genes [#6], and is post-translationally tuned by signaling—ERK phosphorylates Ser986 to promote mitogen-induced immediate-early gene transcription [#8], while PKA phosphorylates Ser983 downstream of GLP-1 receptor signaling to enable beta cell-specific CREB-dependent enhancer programs [#13]. In multicellular organisms MED14 is additionally required cell-autonomously for stem/progenitor cell maintenance and for terminal differentiation of neural crest, where it genetically interacts with the BAF/SWI-SNF chromatin-remodeling complex [#10, #11]. The yeast ortholog Rgr1 is an essential Mediator component that organizes chromatin and mediates both transcriptional repression and activation, establishing the deep conservation of these functions [#0, #1, #2].\",\n  \"teleology\": [\n    {\n      \"year\": 1990,\n      \"claim\": \"Established that the MED14 ortholog is an essential gene whose disruption causes pleiotropic defects, the first indication of a broad regulatory function.\",\n      \"evidence\": \"Gene cloning by complementation with null and truncation mutant analysis, EM, and carbohydrate assays in yeast\",\n      \"pmids\": [\"2196447\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular function not yet linked to transcription machinery\", \"C-terminal truncation phenotypes not mechanistically resolved\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Defined the MED14 ortholog Rgr1 as a physical subunit of the Mediator/Pol II holoenzyme that, with Sin4, organizes chromatin and governs both repression and activation, placing it within the transcription apparatus.\",\n      \"evidence\": \"Biochemical co-purification of Mediator/Pol II holoenzyme plus GST pulldown, genetic epistasis, and superhelical density assays in yeast\",\n      \"pmids\": [\"7479899\", \"7635307\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Architectural role within Mediator undefined\", \"Direct Pol II contact not mapped\", \"Mammalian equivalence not yet shown\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Showed the ortholog functions in a defined transcriptional repression pathway downstream of a regulator, demonstrating gene-specific regulatory engagement.\",\n      \"evidence\": \"Genetic selection for repression-deficient mutants, reporter assays, and protein-level analysis (RME1/IME1) in yeast\",\n      \"pmids\": [\"7851756\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular target of repression unknown\", \"Single-pathway readout\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Connected the ortholog to an early step in Pol II function by showing it is required for both Ser-2 and Ser-5 CTD phosphorylation and broad mRNA transcription.\",\n      \"evidence\": \"RNAi knockdown in C. elegans embryos with immunofluorescence for CTD phosphorylation and transcription assays\",\n      \"pmids\": [\"12089139\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CTD phosphorylation effect is direct or downstream of recruitment unresolved\", \"No biochemical mechanism\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Refined the pathway logic by placing Rgr1/Sin4 Mediator in a common, non-redundant pathway with SWI/SNF chromatin remodeling at target genes.\",\n      \"evidence\": \"Genetic epistasis of double mutants and reporter assays at MAL genes in yeast\",\n      \"pmids\": [\"15514050\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physical basis of Mediator-SWI/SNF cooperation not shown\", \"Single-locus analysis\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstrated a gene-selective, direct activator-tethering role by mapping a ligand-independent MED14–PPARγ N-terminal domain interaction required for transactivation and adipogenesis.\",\n      \"evidence\": \"siRNA knockdown, direct NTD binding assay, ChIP, and 3T3-L1 differentiation assay\",\n      \"pmids\": [\"20194623\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"MED14 region binding PPARγ-NTD not mapped\", \"Structural basis of selective promoter vs enhancer occupancy unresolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Extended gene-selective activation to the glucocorticoid receptor, showing MED14 is needed for some but not all GR targets and controls coactivator recruitment to GREs.\",\n      \"evidence\": \"siRNA knockdown of MED14/MED1 with RT-qPCR and ChIP for GR, MED14, MED1, Pol II\",\n      \"pmids\": [\"16239257\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Determinant of gene selectivity unknown\", \"Direct GR-MED14 contact not demonstrated\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified MED14 as a signal-responsive node by showing ERK directly phosphorylates Ser986 to drive immediate-early gene transcription via enhanced CDK8/Pol II recruitment.\",\n      \"evidence\": \"In vitro ERK kinase assay, S986 phosphosite mapping by mutagenesis, RNAi/ChIP, reporter assays, and Elk-1 Co-IP\",\n      \"pmids\": [\"24049075\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural consequence of S986 phosphorylation on Mediator undefined\", \"Elk-1/MED14 interaction interface not mapped\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved MED14's core mechanistic role by showing its incorporation is required for the core Mediator to acquire transcription function and to associate strongly with Pol II, defining it as the complex's backbone.\",\n      \"evidence\": \"In vitro reconstitution of 15-subunit human core Mediator, functional transcription assays, CX-MS, and Pol II association assays\",\n      \"pmids\": [\"25383669\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-resolution contacts to Pol II not yet defined\", \"Which subdomain mediates Pol II binding not localized\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed in vivo that MED14 has a cell-autonomous role in stem/progenitor maintenance and neural crest terminal differentiation, genetically interacting with the BAF complex, beyond global transcription.\",\n      \"evidence\": \"Zebrafish forward-genetic mutants, microarray transcriptomics, cell transplantation, planarian RNAi, and brg1 double-mutant epistasis\",\n      \"pmids\": [\"25772472\", \"26553192\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific MED14-dependent gene programs in stem cells not identified\", \"Molecular basis of Mediator-BAF interaction not shown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Localized the functional and Pol II-binding activity to the MED14 N-terminal domain, which directly binds hypophosphorylated RPB1 and is sufficient for basal and p53-activated transcription and Pol II recruitment.\",\n      \"evidence\": \"MultiBac reconstitution of core Mediator subcomplexes, in vitro transcription, direct RPB1 binding/competition assay, LC-MS/MS CTD phospho-analysis, and cryo-EM reanalysis\",\n      \"pmids\": [\"41110510\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic structure of the MED14-NTD/RPB1 interface not solved\", \"How CTD phosphorylation state is sensed mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined a second signaling input by showing PKA phosphorylates Ser983 downstream of GLP-1 receptor signaling to enable beta cell-specific CREB enhancer programs.\",\n      \"evidence\": \"Proteomic/phosphoproteomic screens identifying Ser983 and a Med14 S983A knock-in mouse with islet transcriptomics, ChIP, and beta-cell counts\",\n      \"pmids\": [\"41779793\", \"40667025\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How S983 phosphorylation distinguishes beta cell-specific from immediate-early CREB targets unresolved\", \"Structural effect of phosphorylation not shown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How signaling-driven phosphorylation of the MED14 disordered region and its activator-binding surfaces are integrated to produce gene-selective output within the Mediator scaffold remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No atomic structure of MED14 phosphosite or activator interfaces\", \"Mechanism linking phosphorylation to selective enhancer/promoter engagement unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [6, 7, 9]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [9, 12]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [7, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [6, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [9, 12]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [8, 13]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [10, 11]}\n    ],\n    \"complexes\": [\n      \"Mediator complex\",\n      \"RNA polymerase II holoenzyme\"\n    ],\n    \"partners\": [\n      \"RPB1\",\n      \"PPARG\",\n      \"ELK1\",\n      \"MED1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}