{"gene":"MUC17","run_date":"2026-04-29T11:37:56","timeline":{"discoveries":[{"year":2002,"finding":"MUC17 is a membrane-tethered mucin with an extended extracellular glycosylation domain and a carboxyl terminus containing two EGF-like domains, a SEA module domain, a transmembrane domain, and a cytoplasmic domain with potential serine and tyrosine phosphorylation sites.","method":"cDNA cloning, sequence analysis, RNA blot analysis, in situ hybridization","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 — original structural characterization by direct sequencing and expression analysis, foundational paper with 175 citations","pmids":["11855812"],"is_preprint":false},{"year":2006,"finding":"MUC17 alternate splicing generates two variants coding for a membrane-anchored and a secreted form; the gene is regulated by a 1,146-bp promoter fragment containing VDR/RXR, GATA, NFκB, and Cdx-2 response elements.","method":"RACE-PCR, in vitro transcription/translation assays, promoter analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — direct in vitro transcription/translation and promoter characterization with multiple methods","pmids":["16737958"],"is_preprint":false},{"year":2003,"finding":"N-glycosylation is required for the surface localization of MUC17; only forms bearing complex-type N-glycans are localized to the cell surface, and inhibition of N-glycosylation (tunicamycin) or protein transport (brefeldin A) prevents surface localization.","method":"Surface biotinylation, N-glycan-specific hydrolases, SDS-PAGE/Western blot, N-glycosylation inhibitor treatment","journal":"International journal of oncology","confidence":"High","confidence_rationale":"Tier 1 — direct biochemical assays with specific inhibitors and surface biotinylation demonstrating causal relationship","pmids":["12888891"],"is_preprint":false},{"year":2008,"finding":"The C-terminal cytoplasmic tail of MUC17 binds scaffold protein PDZK1 via its PDZ-interaction motif (engaging three of four PDZ domains in PDZK1), and this interaction is required to stably localize MUC17 at the enterocyte apical (brush border) membrane; in Pdzk1-/- mice, the mouse ortholog Muc3(17) shifts from brush border to intracellular localization.","method":"PDZ domain array screening, GST pull-down with mass spectrometry, immunostaining of wild-type vs. Pdzk1-/- mouse jejunum","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 — GST pulldown confirmed by MS, validated by genetic KO mouse model with direct immunostaining readout","pmids":["17990980"],"is_preprint":false},{"year":2010,"finding":"The EGF-like cysteine-rich domain (CRD1-L-CRD2) of MUC17 promotes intestinal cell migration, inhibits apoptosis, and stimulates ERK phosphorylation; ERK inhibition abolishes these effects. Loss of endogenous MUC17 reduces cell-cell adherence and migration and increases apoptosis.","method":"shRNA knockdown, recombinant protein treatment, cell migration assay, apoptosis assay, ERK phosphorylation western blot, in vivo colitis model","journal":"The international journal of biochemistry & cell biology","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function and gain-of-function with defined cellular phenotypes and pathway placement via ERK inhibition","pmids":["20211273"],"is_preprint":false},{"year":2010,"finding":"Recombinant MUC17-CRD1-L-CRD2 protein requires a full-length intervening linker-SEA segment for anti-apoptotic and pro-migratory activity; truncated linker versions or linker alone are inactive.","method":"Recombinant protein production (E. coli and baculovirus systems), cell migration and apoptosis assays","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 1 — in vitro reconstitution with domain truncation analysis, single study","pmids":["20332014"],"is_preprint":false},{"year":2010,"finding":"MUC17 expression is regulated epigenetically by DNA methylation and histone H3-K9 modification at the 5' flanking region; MUC17-negative cell lines have high promoter methylation and repressive H3-K9 marks, whereas MUC17-positive cells have low methylation.","method":"Bisulfite sequencing, chromatin immunoprecipitation (ChIP), treatment with methylation inhibitors","journal":"Glycobiology","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and bisulfite sequencing showing epigenetic mechanism, single study","pmids":["20926598"],"is_preprint":false},{"year":2011,"finding":"MUC17 promotes epithelial barrier integrity; siRNA-mediated reduction of MUC17 increases paracellular permeability, induces iNOS and COX-2, and enhances bacterial invasion by enteroinvasive E. coli (EIEC) without affecting bacterial adhesion.","method":"siRNA knockdown, transepithelial electrical resistance measurement, permeability assay, bacterial invasion assay, western blot","journal":"American journal of physiology. Gastrointestinal and liver physiology","confidence":"Medium","confidence_rationale":"Tier 2 — siRNA KD with multiple functional readouts, single study","pmids":["21393431"],"is_preprint":false},{"year":2012,"finding":"MUC17 expression is induced under hypoxia via a HIF1α-dependent pathway; this induction requires unmethylated CpG motifs within the hypoxia responsive element (HRE). Methylation of HRE blocks HIF1α binding and hypoxic induction; demethylation with 5-aza-2'-deoxycytidine restores hypoxic induction.","method":"Hypoxic cell culture, HIF1α pathway analysis, bisulfite sequencing of HRE, 5-aza-2'-deoxycytidine treatment, reporter assays","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological demethylation restores HIF1α-dependent induction, multiple cell lines tested, single study","pmids":["22970168"],"is_preprint":false},{"year":2013,"finding":"Upon carbachol (CCh) stimulation, MUC17 (but not MUC3 or MUC12) undergoes specific endocytosis from the apical membrane: MUC17 dissociates from PDZK1, relocates to the terminal web and early endosomes, and this is concomitant with NHE3 internalization and CFTR recruitment to the apical membrane for bicarbonate secretion.","method":"Surface labeling, confocal imaging, pharmacological stimulation (carbachol), subcellular fractionation, colocalization analysis in Caco-2 cells and murine enterocytes","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 2 — direct live-cell imaging and surface labeling with functional consequence (ion channel trafficking), validated in two model systems","pmids":["23784542"],"is_preprint":false},{"year":2019,"finding":"TNFα stimulation increases MUC17 protein levels and promotes insertion of MUC17 into apical membranes of enterocytes, followed by shedding of MUC17-containing vesicles. Two phosphorylated serine residues (S4428 and S4492) were identified in the cytoplasmic tail; the C-terminal PDZ-binding site phosphorylation (S4492) modulates function. Apical MUC17 (including phosphodeficient S4492A variant) acts as a decoy to protect against EPEC adhesion.","method":"Mass spectrometry (phosphosite identification), site-directed mutagenesis, Caco-2 cell imaging, bacterial adhesion assay, TNFα stimulation","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 — MS-identified phosphosites validated by mutagenesis with functional readout, multiple orthogonal methods","pmids":["31387973"],"is_preprint":false},{"year":2019,"finding":"MUC17 inhibits NF-κB activity and CEACAM1-3S expression in H. pylori-infected gastric cancer cells, and prevents H. pylori CagA translocation into gastric cells; MUC17 downregulation is mediated by DNMT1-dependent promoter methylation upon H. pylori infection.","method":"Gain- and loss-of-function assays, H. pylori infection model, CagA translocation assay, NF-κB reporter assay, bisulfite sequencing","journal":"Gastric cancer","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays with defined molecular mechanism, single study","pmids":["30778796"],"is_preprint":false},{"year":2023,"finding":"In acquired EGFR-TKI resistance, the UHRF1/DNMT1 complex mediates promoter hypermethylation of MUC17, suppressing its expression. Loss of MUC17 activates NF-κB signaling; MUC17 promotes IκB-α generation via MZF1 to inhibit NF-κB activity.","method":"Drug-resistant cell line models, DNMT1 inhibitor (5-Aza) rescue experiments, chromatin immunoprecipitation, NF-κB reporter assay, in vivo xenograft","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological rescue and functional assays define the pathway, single study","pmids":["36778111"],"is_preprint":false},{"year":2024,"finding":"Muc17 deletion in mice renders the small intestine susceptible to bacterial infection and spontaneous deterioration of epithelial homeostasis with extraluminal bacterial translocation. In human Crohn's disease ileum, reduced MUC17 correlates with a compromised glycocalyx barrier permitting bacterial contact with enterocytes. Muc17-deficient mice harbor specific small intestinal bacterial taxa observed in CD patients.","method":"Muc17 knockout mouse model, bacterial culture/16S sequencing, histology, in vivo bacterial challenge","journal":"JCI insight","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined in vivo phenotype validated across multiple bacterial challenge conditions and linked to human disease","pmids":["39699961"],"is_preprint":false},{"year":2025,"finding":"MYO1B regulates MUC17 protein levels in enterocytes, MYO5B specifically governs MUC17 levels at the brush border, and SNX27 controls MUC17 turnover at the brush border; these motor proteins and sorting nexin are required for correct apical targeting of MUC17 in enterocytes.","method":"siRNA knockdown of MYO1B, MYO5B, SNX27; confocal imaging; biochemical fractionation; bacterial adhesion assay in enterocytes","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with defined subcellular localization phenotype, single study","pmids":["39661054"],"is_preprint":false}],"current_model":"MUC17 is a large membrane-tethered mucin expressed on the apical brush border of intestinal enterocytes, where it forms a protective glycocalyx: its cytoplasmic tail is anchored at the apical membrane by scaffolding protein PDZK1 (via a PDZ-binding motif), its surface localization requires complex-type N-glycosylation, apical targeting depends on motor proteins MYO1B/MYO5B and sorting nexin SNX27, it undergoes stimulus-specific (carbachol) endocytosis concomitant with NHE3 internalization and CFTR recruitment, it is upregulated and shed in response to TNFα to act as a bacterial decoy, its extracellular EGF-like cysteine-rich domains (CRD1-L-CRD2) promote epithelial restitution via ERK phosphorylation, and its expression is epigenetically regulated by promoter DNA methylation (via DNMT1/UHRF1) and H3-K9 histone modifications as well as by HIF1α under hypoxia."},"narrative":{"teleology":[{"year":2002,"claim":"Establishing the domain architecture of MUC17 as a transmembrane mucin with EGF-like domains, a SEA module, and a cytoplasmic tail resolved the gene's identity as a membrane-tethered mucin distinct from secreted gel-forming mucins.","evidence":"cDNA cloning, sequence analysis, RNA blot, and in situ hybridization","pmids":["11855812"],"confidence":"High","gaps":["No functional role assigned to any domain","Post-translational processing of SEA module not addressed"]},{"year":2003,"claim":"Demonstrating that complex-type N-glycosylation is required for MUC17 surface localization established a quality-control step governing its membrane delivery.","evidence":"Surface biotinylation with N-glycan hydrolases and tunicamycin/brefeldin A inhibitor treatments","pmids":["12888891"],"confidence":"High","gaps":["Specific N-glycosylation sites not mapped","Whether glycosylation affects mucin barrier function not tested"]},{"year":2006,"claim":"Identification of alternate splicing producing membrane-anchored and secreted MUC17 isoforms, together with promoter elements (VDR/RXR, GATA, NF-κB, Cdx-2), revealed transcriptional logic controlling tissue-specific expression.","evidence":"RACE-PCR, in vitro transcription/translation, promoter-reporter analysis","pmids":["16737958"],"confidence":"High","gaps":["Relative abundance of secreted vs. membrane isoform in vivo unknown","Individual transcription factor contributions not dissected in vivo"]},{"year":2008,"claim":"Discovery that PDZK1 scaffolds MUC17 at the brush border via its PDZ-binding motif — and that Pdzk1 knockout displaces the mouse ortholog to intracellular compartments — identified the mechanism anchoring MUC17 at the apical membrane.","evidence":"PDZ domain array, GST pull-down with mass spectrometry, immunostaining in wild-type vs. Pdzk1−/− mouse jejunum","pmids":["17990980"],"confidence":"High","gaps":["Whether PDZK1 loss compromises barrier function not tested","Other PDZ partners not excluded"]},{"year":2010,"claim":"Showing that the EGF-like CRD1-L-CRD2 domain stimulates ERK-dependent cell migration and inhibits apoptosis — while MUC17 knockdown reduces cell-cell adherence — established MUC17 as an active signaling mucin that promotes epithelial restitution.","evidence":"shRNA knockdown, recombinant CRD protein treatment, ERK inhibitor experiments, cell migration and apoptosis assays, domain truncation analysis","pmids":["20211273","20332014"],"confidence":"High","gaps":["Receptor that transduces the ERK signal not identified","In vivo wound-healing relevance not demonstrated at that time"]},{"year":2010,"claim":"Demonstrating that MUC17 promoter DNA methylation and H3-K9 histone modifications control its expression revealed an epigenetic switch that silences MUC17 in non-expressing cell types.","evidence":"Bisulfite sequencing, ChIP for histone marks, methylation inhibitor treatment across multiple cell lines","pmids":["20926598"],"confidence":"Medium","gaps":["Enzymes responsible for establishing these marks not identified in this study","In vivo epigenetic regulation not assessed"]},{"year":2011,"claim":"Loss-of-function experiments showing that MUC17 depletion increases paracellular permeability, induces iNOS/COX-2, and enhances enteroinvasive bacterial invasion established MUC17 as a functional barrier component, not merely a passive glycocalyx element.","evidence":"siRNA knockdown in enterocytes, transepithelial resistance, permeability assay, EIEC invasion assay","pmids":["21393431"],"confidence":"Medium","gaps":["Whether barrier loss is due to glycocalyx thinning or altered signaling not resolved","Single cell-line system"]},{"year":2012,"claim":"Showing that HIF1α induces MUC17 under hypoxia — but only when the HRE is unmethylated — integrated epigenetic and oxygen-sensing pathways into a unified regulatory model.","evidence":"Hypoxic culture, HIF1α pathway analysis, bisulfite sequencing of HRE, 5-aza-2′-deoxycytidine rescue, reporter assays","pmids":["22970168"],"confidence":"Medium","gaps":["Physiological relevance of hypoxic MUC17 induction in intestinal ischemia not tested in vivo","Whether HIF2α also contributes not addressed"]},{"year":2013,"claim":"Demonstrating that carbachol triggers specific MUC17 endocytosis concomitant with NHE3 internalization and CFTR apical recruitment revealed that MUC17 participates in coordinated ion/mucin trafficking at the brush border.","evidence":"Surface labeling, confocal imaging, pharmacological stimulation, subcellular fractionation in Caco-2 cells and murine enterocytes","pmids":["23784542"],"confidence":"High","gaps":["Molecular machinery linking MUC17-PDZK1 dissociation to endocytosis unknown","Whether CFTR recruitment is MUC17-dependent or parallel not determined"]},{"year":2019,"claim":"Identification of phosphorylated serines (S4428, S4492) in the MUC17 cytoplasmic tail — with S4492 modulating PDZ-binding and apical retention — together with TNFα-induced shedding that yields decoy vesicles blocking EPEC adhesion, established MUC17 as an actively regulated anti-microbial effector.","evidence":"Mass spectrometry phosphosite mapping, site-directed mutagenesis, TNFα stimulation, bacterial adhesion assay in Caco-2 cells","pmids":["31387973"],"confidence":"High","gaps":["Kinase(s) phosphorylating S4428 and S4492 not identified","Whether shed MUC17 vesicles function in vivo not tested"]},{"year":2019,"claim":"Showing that MUC17 inhibits NF-κB and prevents H. pylori CagA translocation — and that H. pylori silences MUC17 via DNMT1-dependent methylation — identified MUC17 as a gastric defense factor subverted by pathogen epigenetic manipulation.","evidence":"Gain- and loss-of-function in gastric cancer cells, H. pylori infection, CagA translocation assay, NF-κB reporter, bisulfite sequencing","pmids":["30778796"],"confidence":"Medium","gaps":["Mechanism linking MUC17 to CagA injection blockade unclear","Relevance to in vivo gastric colonization not tested"]},{"year":2023,"claim":"Demonstrating that UHRF1/DNMT1-mediated MUC17 silencing activates NF-κB in EGFR-TKI-resistant cells — and that MUC17 re-expression restores IκB-α via MZF1 — defined a mechanistic link between MUC17 loss and inflammatory signaling in drug resistance.","evidence":"Drug-resistant cell lines, 5-Aza rescue, ChIP, NF-κB reporter, xenograft","pmids":["36778111"],"confidence":"Medium","gaps":["Direct physical interaction between MUC17 and MZF1 or IκB-α pathway components not shown","Generalizability beyond EGFR-TKI resistance context unclear"]},{"year":2024,"claim":"Genetic deletion of Muc17 in mice proved that MUC17 is essential for small intestinal barrier integrity in vivo: knockout mice exhibit spontaneous bacterial translocation and harbor bacterial communities resembling those in Crohn's disease ileum, directly linking MUC17 loss to IBD-related barrier failure.","evidence":"Muc17 knockout mouse, bacterial challenge, 16S sequencing, histology, comparison with human Crohn's disease ileal biopsies","pmids":["39699961"],"confidence":"High","gaps":["Whether Muc17 loss is compensated by other membrane mucins over time not assessed","Causal direction of MUC17 reduction in human CD not established"]},{"year":2025,"claim":"Identification of MYO1B, MYO5B, and SNX27 as regulators of MUC17 apical targeting and brush border turnover mapped the intracellular trafficking machinery that delivers MUC17 to its functional location.","evidence":"siRNA knockdown of MYO1B, MYO5B, SNX27; confocal imaging; biochemical fractionation; bacterial adhesion assay","pmids":["39661054"],"confidence":"Medium","gaps":["Whether these motors act sequentially or in parallel not resolved","Vesicular intermediates carrying MUC17 not characterized"]},{"year":null,"claim":"Key unresolved questions include the identity of the kinase(s) phosphorylating the MUC17 cytoplasmic tail, the receptor that transduces EGF-like domain signaling through ERK, the structural basis of CRD1-L-CRD2 activity, whether shed MUC17 vesicles function as bacterial decoys in vivo, and whether therapeutic re-expression of MUC17 (e.g., via demethylation) can restore barrier function in IBD.","evidence":"","pmids":[],"confidence":"Low","gaps":["No kinase identified for S4428/S4492 phosphorylation","No receptor identified for CRD-mediated ERK signaling","No structural model of the MUC17 ectodomain"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,7,11,12]},{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[4,7,13]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,3,9,10,14]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[9]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[1,10]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,12]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[7,10,11,13]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[3,9,14]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[6,8]}],"complexes":[],"partners":["PDZK1","MYO1B","MYO5B","SNX27","NHE3","DNMT1","UHRF1","HIF1A"],"other_free_text":[]},"mechanistic_narrative":"MUC17 is a membrane-tethered mucin that forms the protective glycocalyx on the apical brush border of intestinal enterocytes, serving as a critical barrier against bacterial invasion and maintaining epithelial homeostasis. Its surface localization requires complex-type N-glycosylation, scaffolding by PDZK1 via a C-terminal PDZ-binding motif, and apical trafficking mediated by MYO1B, MYO5B, and SNX27; upon cholinergic (carbachol) or inflammatory (TNFα) stimulation, MUC17 undergoes stimulus-specific endocytosis or shedding that coordinately regulates ion transporter trafficking and serves as a bacterial decoy against pathogen adhesion [PMID:12888891, PMID:17990980, PMID:23784542, PMID:31387973, PMID:39661054]. The extracellular EGF-like cysteine-rich domains (CRD1-L-CRD2) promote epithelial restitution by stimulating ERK-dependent cell migration and inhibiting apoptosis, while MUC17 suppresses NF-κB signaling through promotion of IκB-α generation [PMID:20211273, PMID:36778111]. MUC17 expression is epigenetically silenced by DNMT1/UHRF1-mediated promoter methylation and repressive H3-K9 histone marks, and is induced under hypoxia via HIF1α binding to unmethylated hypoxia-responsive elements; genetic deletion of Muc17 in mice causes spontaneous loss of epithelial barrier integrity and bacterial translocation, phenocopying features of human Crohn's disease [PMID:20926598, PMID:22970168, PMID:39699961]."},"prefetch_data":{"uniprot":{"accession":"Q685J3","full_name":"Mucin-17","aliases":["Small intestinal mucin-3","MUC-3"],"length_aa":4493,"mass_kda":451.7,"function":"Probably plays a role in maintaining homeostasis on mucosal surfaces","subcellular_location":"Secreted; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q685J3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MUC17","classification":"Not Classified","n_dependent_lines":22,"n_total_lines":1208,"dependency_fraction":0.018211920529801324},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/MUC17","total_profiled":1310},"omim":[{"mim_id":"608424","title":"MUCIN 17; MUC17","url":"https://www.omim.org/entry/608424"},{"mim_id":"266600","title":"INFLAMMATORY BOWEL DISEASE (CROHN DISEASE) 1; IBD1","url":"https://www.omim.org/entry/266600"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in single","driving_tissues":[{"tissue":"intestine","ntpm":41.4}],"url":"https://www.proteinatlas.org/search/MUC17"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q685J3","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q685J3","model_url":"","pae_url":"","plddt_mean":null},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MUC17","jax_strain_url":"https://www.jax.org/strain/search?query=MUC17"},"sequence":{"accession":"Q685J3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q685J3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q685J3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q685J3"}},"corpus_meta":[{"pmid":"11855812","id":"PMC_11855812","title":"MUC17, a novel membrane-tethered mucin.","date":"2002","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11855812","citation_count":175,"is_preprint":false},{"pmid":"16737958","id":"PMC_16737958","title":"Characterization of human mucin MUC17. Complete coding sequence and organization.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16737958","citation_count":51,"is_preprint":false},{"pmid":"20702471","id":"PMC_20702471","title":"Expression of intestinal MUC17 membrane-bound mucin in inflammatory and neoplastic diseases of the colon.","date":"2010","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/20702471","citation_count":42,"is_preprint":false},{"pmid":"17990980","id":"PMC_17990980","title":"The C-terminus of the transmembrane mucin MUC17 binds to the scaffold protein PDZK1 that stably localizes it to the enterocyte apical membrane in the small intestine.","date":"2008","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/17990980","citation_count":41,"is_preprint":false},{"pmid":"21393431","id":"PMC_21393431","title":"Muc17 protects intestinal epithelial cells from enteroinvasive E. coli infection by promoting epithelial barrier integrity.","date":"2011","source":"American journal of physiology. Gastrointestinal and liver physiology","url":"https://pubmed.ncbi.nlm.nih.gov/21393431","citation_count":30,"is_preprint":false},{"pmid":"20211273","id":"PMC_20211273","title":"Human intestinal MUC17 mucin augments intestinal cell restitution and enhances healing of experimental colitis.","date":"2010","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/20211273","citation_count":29,"is_preprint":false},{"pmid":"12898407","id":"PMC_12898407","title":"[Normal human conjunctival epithelium expresses MUC13, MUC15, MUC16 and MUC17 mucin genes].","date":"2003","source":"Archivos de la Sociedad Espanola de Oftalmologia","url":"https://pubmed.ncbi.nlm.nih.gov/12898407","citation_count":28,"is_preprint":false},{"pmid":"20926598","id":"PMC_20926598","title":"DNA methylation and histone H3-K9 modifications contribute to MUC17 expression.","date":"2010","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/20926598","citation_count":26,"is_preprint":false},{"pmid":"36778111","id":"PMC_36778111","title":"Acquired resistance to EGFR-TKIs in NSCLC mediates epigenetic downregulation of MUC17 by facilitating NF-κB activity via UHRF1/DNMT1 complex.","date":"2023","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36778111","citation_count":22,"is_preprint":false},{"pmid":"22970168","id":"PMC_22970168","title":"Expression of MUC17 is regulated by HIF1α-mediated hypoxic responses and requires a methylation-free hypoxia responsible element in pancreatic cancer.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22970168","citation_count":20,"is_preprint":false},{"pmid":"30778796","id":"PMC_30778796","title":"Epigenetic downregulation of MUC17 by H. pylori infection facilitates NF-κB-mediated expression of CEACAM1-3S in human gastric cancer.","date":"2019","source":"Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association","url":"https://pubmed.ncbi.nlm.nih.gov/30778796","citation_count":20,"is_preprint":false},{"pmid":"23784542","id":"PMC_23784542","title":"Carbachol-induced MUC17 endocytosis is concomitant with NHE3 internalization and CFTR membrane recruitment in enterocytes.","date":"2013","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/23784542","citation_count":19,"is_preprint":false},{"pmid":"12888891","id":"PMC_12888891","title":"N-glycosylation is required for the surface localization of MUC17 mucin.","date":"2003","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/12888891","citation_count":19,"is_preprint":false},{"pmid":"20332014","id":"PMC_20332014","title":"Activity of recombinant cysteine-rich domain proteins derived from the membrane-bound MUC17/Muc3 family mucins.","date":"2010","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/20332014","citation_count":17,"is_preprint":false},{"pmid":"31879365","id":"PMC_31879365","title":"Genomic and Expression Analyses Define MUC17 and PCNX1 as Predictors of Chemotherapy Response in Breast Cancer.","date":"2019","source":"Molecular cancer therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/31879365","citation_count":17,"is_preprint":false},{"pmid":"31387973","id":"PMC_31387973","title":"The human transmembrane mucin MUC17 responds to TNFα by increased presentation at the plasma membrane.","date":"2019","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/31387973","citation_count":13,"is_preprint":false},{"pmid":"26285705","id":"PMC_26285705","title":"Genetic variations of MUC17 are associated with endometriosis development and related infertility.","date":"2015","source":"BMC medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/26285705","citation_count":13,"is_preprint":false},{"pmid":"39699961","id":"PMC_39699961","title":"MUC17 is an essential small intestinal glycocalyx component that is disrupted in Crohn's disease.","date":"2024","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/39699961","citation_count":7,"is_preprint":false},{"pmid":"39580962","id":"PMC_39580962","title":"Identification and validation of serum MUC17 as a non-invasive early warning biomarker for screening of gastric intraepithelial neoplasia.","date":"2024","source":"Translational oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39580962","citation_count":3,"is_preprint":false},{"pmid":"36945389","id":"PMC_36945389","title":"The MYO1B and MYO5B motor proteins and the SNX27 sorting nexin regulate membrane mucin MUC17 trafficking in enterocytes.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/36945389","citation_count":1,"is_preprint":false},{"pmid":"41253489","id":"PMC_41253489","title":"CAR-T cell therapy targeting MUC17 in gastric tumors.","date":"2025","source":"Journal for immunotherapy of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/41253489","citation_count":0,"is_preprint":false},{"pmid":"39661054","id":"PMC_39661054","title":"The MYO1B and MYO5B motor proteins and the sorting nexin SNX27 regulate apical targeting of membrane mucin MUC17 in enterocytes.","date":"2025","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/39661054","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.06.18.24309133","title":"Whole exome-seq and RNA-seq data reveal unique neoantigen profiles in Kenyan breast cancer patients","date":"2024-06-20","source":"bioRxiv","url":"https://doi.org/10.1101/2024.06.18.24309133","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13465,"output_tokens":3638,"usd":0.047482},"stage2":{"model":"claude-opus-4-6","input_tokens":7100,"output_tokens":3647,"usd":0.190013},"total_usd":0.237495,"stage1_batch_id":"msgbatch_012ZiiCUBfB62NCTQd4Bk1Jo","stage2_batch_id":"msgbatch_01Xuqq9aUHoQouS7UVGZNStZ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"MUC17 is a membrane-tethered mucin with an extended extracellular glycosylation domain and a carboxyl terminus containing two EGF-like domains, a SEA module domain, a transmembrane domain, and a cytoplasmic domain with potential serine and tyrosine phosphorylation sites.\",\n      \"method\": \"cDNA cloning, sequence analysis, RNA blot analysis, in situ hybridization\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — original structural characterization by direct sequencing and expression analysis, foundational paper with 175 citations\",\n      \"pmids\": [\"11855812\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"MUC17 alternate splicing generates two variants coding for a membrane-anchored and a secreted form; the gene is regulated by a 1,146-bp promoter fragment containing VDR/RXR, GATA, NFκB, and Cdx-2 response elements.\",\n      \"method\": \"RACE-PCR, in vitro transcription/translation assays, promoter analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro transcription/translation and promoter characterization with multiple methods\",\n      \"pmids\": [\"16737958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"N-glycosylation is required for the surface localization of MUC17; only forms bearing complex-type N-glycans are localized to the cell surface, and inhibition of N-glycosylation (tunicamycin) or protein transport (brefeldin A) prevents surface localization.\",\n      \"method\": \"Surface biotinylation, N-glycan-specific hydrolases, SDS-PAGE/Western blot, N-glycosylation inhibitor treatment\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct biochemical assays with specific inhibitors and surface biotinylation demonstrating causal relationship\",\n      \"pmids\": [\"12888891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"The C-terminal cytoplasmic tail of MUC17 binds scaffold protein PDZK1 via its PDZ-interaction motif (engaging three of four PDZ domains in PDZK1), and this interaction is required to stably localize MUC17 at the enterocyte apical (brush border) membrane; in Pdzk1-/- mice, the mouse ortholog Muc3(17) shifts from brush border to intracellular localization.\",\n      \"method\": \"PDZ domain array screening, GST pull-down with mass spectrometry, immunostaining of wild-type vs. Pdzk1-/- mouse jejunum\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — GST pulldown confirmed by MS, validated by genetic KO mouse model with direct immunostaining readout\",\n      \"pmids\": [\"17990980\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The EGF-like cysteine-rich domain (CRD1-L-CRD2) of MUC17 promotes intestinal cell migration, inhibits apoptosis, and stimulates ERK phosphorylation; ERK inhibition abolishes these effects. Loss of endogenous MUC17 reduces cell-cell adherence and migration and increases apoptosis.\",\n      \"method\": \"shRNA knockdown, recombinant protein treatment, cell migration assay, apoptosis assay, ERK phosphorylation western blot, in vivo colitis model\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function and gain-of-function with defined cellular phenotypes and pathway placement via ERK inhibition\",\n      \"pmids\": [\"20211273\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Recombinant MUC17-CRD1-L-CRD2 protein requires a full-length intervening linker-SEA segment for anti-apoptotic and pro-migratory activity; truncated linker versions or linker alone are inactive.\",\n      \"method\": \"Recombinant protein production (E. coli and baculovirus systems), cell migration and apoptosis assays\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with domain truncation analysis, single study\",\n      \"pmids\": [\"20332014\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MUC17 expression is regulated epigenetically by DNA methylation and histone H3-K9 modification at the 5' flanking region; MUC17-negative cell lines have high promoter methylation and repressive H3-K9 marks, whereas MUC17-positive cells have low methylation.\",\n      \"method\": \"Bisulfite sequencing, chromatin immunoprecipitation (ChIP), treatment with methylation inhibitors\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and bisulfite sequencing showing epigenetic mechanism, single study\",\n      \"pmids\": [\"20926598\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"MUC17 promotes epithelial barrier integrity; siRNA-mediated reduction of MUC17 increases paracellular permeability, induces iNOS and COX-2, and enhances bacterial invasion by enteroinvasive E. coli (EIEC) without affecting bacterial adhesion.\",\n      \"method\": \"siRNA knockdown, transepithelial electrical resistance measurement, permeability assay, bacterial invasion assay, western blot\",\n      \"journal\": \"American journal of physiology. Gastrointestinal and liver physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — siRNA KD with multiple functional readouts, single study\",\n      \"pmids\": [\"21393431\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"MUC17 expression is induced under hypoxia via a HIF1α-dependent pathway; this induction requires unmethylated CpG motifs within the hypoxia responsive element (HRE). Methylation of HRE blocks HIF1α binding and hypoxic induction; demethylation with 5-aza-2'-deoxycytidine restores hypoxic induction.\",\n      \"method\": \"Hypoxic cell culture, HIF1α pathway analysis, bisulfite sequencing of HRE, 5-aza-2'-deoxycytidine treatment, reporter assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological demethylation restores HIF1α-dependent induction, multiple cell lines tested, single study\",\n      \"pmids\": [\"22970168\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Upon carbachol (CCh) stimulation, MUC17 (but not MUC3 or MUC12) undergoes specific endocytosis from the apical membrane: MUC17 dissociates from PDZK1, relocates to the terminal web and early endosomes, and this is concomitant with NHE3 internalization and CFTR recruitment to the apical membrane for bicarbonate secretion.\",\n      \"method\": \"Surface labeling, confocal imaging, pharmacological stimulation (carbachol), subcellular fractionation, colocalization analysis in Caco-2 cells and murine enterocytes\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct live-cell imaging and surface labeling with functional consequence (ion channel trafficking), validated in two model systems\",\n      \"pmids\": [\"23784542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"TNFα stimulation increases MUC17 protein levels and promotes insertion of MUC17 into apical membranes of enterocytes, followed by shedding of MUC17-containing vesicles. Two phosphorylated serine residues (S4428 and S4492) were identified in the cytoplasmic tail; the C-terminal PDZ-binding site phosphorylation (S4492) modulates function. Apical MUC17 (including phosphodeficient S4492A variant) acts as a decoy to protect against EPEC adhesion.\",\n      \"method\": \"Mass spectrometry (phosphosite identification), site-directed mutagenesis, Caco-2 cell imaging, bacterial adhesion assay, TNFα stimulation\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — MS-identified phosphosites validated by mutagenesis with functional readout, multiple orthogonal methods\",\n      \"pmids\": [\"31387973\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"MUC17 inhibits NF-κB activity and CEACAM1-3S expression in H. pylori-infected gastric cancer cells, and prevents H. pylori CagA translocation into gastric cells; MUC17 downregulation is mediated by DNMT1-dependent promoter methylation upon H. pylori infection.\",\n      \"method\": \"Gain- and loss-of-function assays, H. pylori infection model, CagA translocation assay, NF-κB reporter assay, bisulfite sequencing\",\n      \"journal\": \"Gastric cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays with defined molecular mechanism, single study\",\n      \"pmids\": [\"30778796\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In acquired EGFR-TKI resistance, the UHRF1/DNMT1 complex mediates promoter hypermethylation of MUC17, suppressing its expression. Loss of MUC17 activates NF-κB signaling; MUC17 promotes IκB-α generation via MZF1 to inhibit NF-κB activity.\",\n      \"method\": \"Drug-resistant cell line models, DNMT1 inhibitor (5-Aza) rescue experiments, chromatin immunoprecipitation, NF-κB reporter assay, in vivo xenograft\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological rescue and functional assays define the pathway, single study\",\n      \"pmids\": [\"36778111\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Muc17 deletion in mice renders the small intestine susceptible to bacterial infection and spontaneous deterioration of epithelial homeostasis with extraluminal bacterial translocation. In human Crohn's disease ileum, reduced MUC17 correlates with a compromised glycocalyx barrier permitting bacterial contact with enterocytes. Muc17-deficient mice harbor specific small intestinal bacterial taxa observed in CD patients.\",\n      \"method\": \"Muc17 knockout mouse model, bacterial culture/16S sequencing, histology, in vivo bacterial challenge\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined in vivo phenotype validated across multiple bacterial challenge conditions and linked to human disease\",\n      \"pmids\": [\"39699961\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MYO1B regulates MUC17 protein levels in enterocytes, MYO5B specifically governs MUC17 levels at the brush border, and SNX27 controls MUC17 turnover at the brush border; these motor proteins and sorting nexin are required for correct apical targeting of MUC17 in enterocytes.\",\n      \"method\": \"siRNA knockdown of MYO1B, MYO5B, SNX27; confocal imaging; biochemical fractionation; bacterial adhesion assay in enterocytes\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined subcellular localization phenotype, single study\",\n      \"pmids\": [\"39661054\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MUC17 is a large membrane-tethered mucin expressed on the apical brush border of intestinal enterocytes, where it forms a protective glycocalyx: its cytoplasmic tail is anchored at the apical membrane by scaffolding protein PDZK1 (via a PDZ-binding motif), its surface localization requires complex-type N-glycosylation, apical targeting depends on motor proteins MYO1B/MYO5B and sorting nexin SNX27, it undergoes stimulus-specific (carbachol) endocytosis concomitant with NHE3 internalization and CFTR recruitment, it is upregulated and shed in response to TNFα to act as a bacterial decoy, its extracellular EGF-like cysteine-rich domains (CRD1-L-CRD2) promote epithelial restitution via ERK phosphorylation, and its expression is epigenetically regulated by promoter DNA methylation (via DNMT1/UHRF1) and H3-K9 histone modifications as well as by HIF1α under hypoxia.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MUC17 is a membrane-tethered mucin that forms the protective glycocalyx on the apical brush border of intestinal enterocytes, serving as a critical barrier against bacterial invasion and maintaining epithelial homeostasis. Its surface localization requires complex-type N-glycosylation, scaffolding by PDZK1 via a C-terminal PDZ-binding motif, and apical trafficking mediated by MYO1B, MYO5B, and SNX27; upon cholinergic (carbachol) or inflammatory (TNFα) stimulation, MUC17 undergoes stimulus-specific endocytosis or shedding that coordinately regulates ion transporter trafficking and serves as a bacterial decoy against pathogen adhesion [PMID:12888891, PMID:17990980, PMID:23784542, PMID:31387973, PMID:39661054]. The extracellular EGF-like cysteine-rich domains (CRD1-L-CRD2) promote epithelial restitution by stimulating ERK-dependent cell migration and inhibiting apoptosis, while MUC17 suppresses NF-κB signaling through promotion of IκB-α generation [PMID:20211273, PMID:36778111]. MUC17 expression is epigenetically silenced by DNMT1/UHRF1-mediated promoter methylation and repressive H3-K9 histone marks, and is induced under hypoxia via HIF1α binding to unmethylated hypoxia-responsive elements; genetic deletion of Muc17 in mice causes spontaneous loss of epithelial barrier integrity and bacterial translocation, phenocopying features of human Crohn's disease [PMID:20926598, PMID:22970168, PMID:39699961].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Establishing the domain architecture of MUC17 as a transmembrane mucin with EGF-like domains, a SEA module, and a cytoplasmic tail resolved the gene's identity as a membrane-tethered mucin distinct from secreted gel-forming mucins.\",\n      \"evidence\": \"cDNA cloning, sequence analysis, RNA blot, and in situ hybridization\",\n      \"pmids\": [\"11855812\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No functional role assigned to any domain\", \"Post-translational processing of SEA module not addressed\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrating that complex-type N-glycosylation is required for MUC17 surface localization established a quality-control step governing its membrane delivery.\",\n      \"evidence\": \"Surface biotinylation with N-glycan hydrolases and tunicamycin/brefeldin A inhibitor treatments\",\n      \"pmids\": [\"12888891\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific N-glycosylation sites not mapped\", \"Whether glycosylation affects mucin barrier function not tested\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identification of alternate splicing producing membrane-anchored and secreted MUC17 isoforms, together with promoter elements (VDR/RXR, GATA, NF-κB, Cdx-2), revealed transcriptional logic controlling tissue-specific expression.\",\n      \"evidence\": \"RACE-PCR, in vitro transcription/translation, promoter-reporter analysis\",\n      \"pmids\": [\"16737958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative abundance of secreted vs. membrane isoform in vivo unknown\", \"Individual transcription factor contributions not dissected in vivo\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Discovery that PDZK1 scaffolds MUC17 at the brush border via its PDZ-binding motif — and that Pdzk1 knockout displaces the mouse ortholog to intracellular compartments — identified the mechanism anchoring MUC17 at the apical membrane.\",\n      \"evidence\": \"PDZ domain array, GST pull-down with mass spectrometry, immunostaining in wild-type vs. Pdzk1−/− mouse jejunum\",\n      \"pmids\": [\"17990980\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether PDZK1 loss compromises barrier function not tested\", \"Other PDZ partners not excluded\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showing that the EGF-like CRD1-L-CRD2 domain stimulates ERK-dependent cell migration and inhibits apoptosis — while MUC17 knockdown reduces cell-cell adherence — established MUC17 as an active signaling mucin that promotes epithelial restitution.\",\n      \"evidence\": \"shRNA knockdown, recombinant CRD protein treatment, ERK inhibitor experiments, cell migration and apoptosis assays, domain truncation analysis\",\n      \"pmids\": [\"20211273\", \"20332014\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor that transduces the ERK signal not identified\", \"In vivo wound-healing relevance not demonstrated at that time\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstrating that MUC17 promoter DNA methylation and H3-K9 histone modifications control its expression revealed an epigenetic switch that silences MUC17 in non-expressing cell types.\",\n      \"evidence\": \"Bisulfite sequencing, ChIP for histone marks, methylation inhibitor treatment across multiple cell lines\",\n      \"pmids\": [\"20926598\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Enzymes responsible for establishing these marks not identified in this study\", \"In vivo epigenetic regulation not assessed\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Loss-of-function experiments showing that MUC17 depletion increases paracellular permeability, induces iNOS/COX-2, and enhances enteroinvasive bacterial invasion established MUC17 as a functional barrier component, not merely a passive glycocalyx element.\",\n      \"evidence\": \"siRNA knockdown in enterocytes, transepithelial resistance, permeability assay, EIEC invasion assay\",\n      \"pmids\": [\"21393431\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether barrier loss is due to glycocalyx thinning or altered signaling not resolved\", \"Single cell-line system\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showing that HIF1α induces MUC17 under hypoxia — but only when the HRE is unmethylated — integrated epigenetic and oxygen-sensing pathways into a unified regulatory model.\",\n      \"evidence\": \"Hypoxic culture, HIF1α pathway analysis, bisulfite sequencing of HRE, 5-aza-2′-deoxycytidine rescue, reporter assays\",\n      \"pmids\": [\"22970168\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological relevance of hypoxic MUC17 induction in intestinal ischemia not tested in vivo\", \"Whether HIF2α also contributes not addressed\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Demonstrating that carbachol triggers specific MUC17 endocytosis concomitant with NHE3 internalization and CFTR apical recruitment revealed that MUC17 participates in coordinated ion/mucin trafficking at the brush border.\",\n      \"evidence\": \"Surface labeling, confocal imaging, pharmacological stimulation, subcellular fractionation in Caco-2 cells and murine enterocytes\",\n      \"pmids\": [\"23784542\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular machinery linking MUC17-PDZK1 dissociation to endocytosis unknown\", \"Whether CFTR recruitment is MUC17-dependent or parallel not determined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identification of phosphorylated serines (S4428, S4492) in the MUC17 cytoplasmic tail — with S4492 modulating PDZ-binding and apical retention — together with TNFα-induced shedding that yields decoy vesicles blocking EPEC adhesion, established MUC17 as an actively regulated anti-microbial effector.\",\n      \"evidence\": \"Mass spectrometry phosphosite mapping, site-directed mutagenesis, TNFα stimulation, bacterial adhesion assay in Caco-2 cells\",\n      \"pmids\": [\"31387973\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase(s) phosphorylating S4428 and S4492 not identified\", \"Whether shed MUC17 vesicles function in vivo not tested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showing that MUC17 inhibits NF-κB and prevents H. pylori CagA translocation — and that H. pylori silences MUC17 via DNMT1-dependent methylation — identified MUC17 as a gastric defense factor subverted by pathogen epigenetic manipulation.\",\n      \"evidence\": \"Gain- and loss-of-function in gastric cancer cells, H. pylori infection, CagA translocation assay, NF-κB reporter, bisulfite sequencing\",\n      \"pmids\": [\"30778796\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking MUC17 to CagA injection blockade unclear\", \"Relevance to in vivo gastric colonization not tested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Demonstrating that UHRF1/DNMT1-mediated MUC17 silencing activates NF-κB in EGFR-TKI-resistant cells — and that MUC17 re-expression restores IκB-α via MZF1 — defined a mechanistic link between MUC17 loss and inflammatory signaling in drug resistance.\",\n      \"evidence\": \"Drug-resistant cell lines, 5-Aza rescue, ChIP, NF-κB reporter, xenograft\",\n      \"pmids\": [\"36778111\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct physical interaction between MUC17 and MZF1 or IκB-α pathway components not shown\", \"Generalizability beyond EGFR-TKI resistance context unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Genetic deletion of Muc17 in mice proved that MUC17 is essential for small intestinal barrier integrity in vivo: knockout mice exhibit spontaneous bacterial translocation and harbor bacterial communities resembling those in Crohn's disease ileum, directly linking MUC17 loss to IBD-related barrier failure.\",\n      \"evidence\": \"Muc17 knockout mouse, bacterial challenge, 16S sequencing, histology, comparison with human Crohn's disease ileal biopsies\",\n      \"pmids\": [\"39699961\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Muc17 loss is compensated by other membrane mucins over time not assessed\", \"Causal direction of MUC17 reduction in human CD not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identification of MYO1B, MYO5B, and SNX27 as regulators of MUC17 apical targeting and brush border turnover mapped the intracellular trafficking machinery that delivers MUC17 to its functional location.\",\n      \"evidence\": \"siRNA knockdown of MYO1B, MYO5B, SNX27; confocal imaging; biochemical fractionation; bacterial adhesion assay\",\n      \"pmids\": [\"39661054\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether these motors act sequentially or in parallel not resolved\", \"Vesicular intermediates carrying MUC17 not characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the identity of the kinase(s) phosphorylating the MUC17 cytoplasmic tail, the receptor that transduces EGF-like domain signaling through ERK, the structural basis of CRD1-L-CRD2 activity, whether shed MUC17 vesicles function as bacterial decoys in vivo, and whether therapeutic re-expression of MUC17 (e.g., via demethylation) can restore barrier function in IBD.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No kinase identified for S4428/S4492 phosphorylation\", \"No receptor identified for CRD-mediated ERK signaling\", \"No structural model of the MUC17 ectodomain\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 7, 11, 12]},\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [4, 7, 13]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 3, 9, 10, 14]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [1, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 12]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [7, 10, 11, 13]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [3, 9, 14]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [6, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"PDZK1\",\n      \"MYO1B\",\n      \"MYO5B\",\n      \"SNX27\",\n      \"NHE3\",\n      \"DNMT1\",\n      \"UHRF1\",\n      \"HIF1A\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}