{"gene":"CLDN6","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2019,"finding":"CLDN6 reduces phosphorylation of LATS1/2 and YAP1 by directly interacting with LATS1/2 in the Hippo signaling pathway, thereby promoting YAP1 nuclear entry; nuclear YAP1 then interacts with Snail1 to drive EMT and enhance gastric cancer cell invasiveness.","method":"Co-immunoprecipitation, western blot (phosphorylation assays), in vitro and in vivo functional assays","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP showing CLDN6-LATS1/2 interaction plus downstream phosphorylation assays, single lab","pmids":["31827075"],"is_preprint":false},{"year":2021,"finding":"CLDN6 interacts with TJP2 (tight junction protein 2), and this CLDN6/TJP2 complex activates YAP1 via the Hippo signaling pathway, inducing phenotypic shift of hepatocellular carcinoma cells from hepatic to biliary lineage and conferring sorafenib resistance.","method":"Co-immunoprecipitation, functional cell line assays, overexpression studies","journal":"Science translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of CLDN6/TJP2 complex with functional validation, single lab","pmids":["33536280"],"is_preprint":false},{"year":2019,"finding":"ERβ transcriptionally upregulates CLDN6 expression (confirmed by ChIP and dual luciferase reporter assays), and CLDN6 in turn positively regulates beclin1 to induce beclin1-dependent autophagy, thereby inhibiting breast cancer cell migration and invasion.","method":"ChIP assay, dual luciferase reporter assay, western blot, immunofluorescence, transmission electron microscopy, xenograft mouse models","journal":"Journal of experimental & clinical cancer research","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — ChIP + dual luciferase reporter + rescue experiments with beclin1 knockdown, multiple orthogonal methods in single lab","pmids":["31412908"],"is_preprint":false},{"year":2016,"finding":"CLDN6 restoration in MCF-7 breast cancer cells decreases ASK1 phosphorylation at Ser967, activating downstream JNK and p38 kinase; inhibition of ASK1 with TRX1 suppressed JNK/p38 activation, reversed apoptosis, and increased Bcl-2/Bax ratio and reduced caspase-3 cleavage, placing CLDN6 upstream of the ASK1-p38/JNK apoptotic pathway.","method":"Stable transfection, pharmacological inhibition (TRX1), TUNEL staining, DNA ladder, western blot, colony formation assay","journal":"International journal of oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple functional assays plus pharmacological rescue, single lab","pmids":["27035750"],"is_preprint":false},{"year":2017,"finding":"CLDN6 interacts with p53 and promotes translocation of p53 from nucleus to cytoplasm; this nuclear exclusion of p53 upregulates GSTP1 expression and GST enzyme activity, conferring chemoresistance to adriamycin, 5-FU, and cisplatin in breast cancer cells.","method":"Co-immunoprecipitation, RNAi knockdown/overexpression, CCK-8 cytotoxicity assay, GST activity kit, western blot","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of CLDN6-p53, functional rescue with GSTP1 manipulation, single lab","pmids":["29116019"],"is_preprint":false},{"year":2017,"finding":"CLDN6 co-localizes and physically interacts with AF-6 (afadin); CLDN6 overexpression increases AF-6 expression and suppresses ERK signaling activation, upregulating cancer stem cell markers (OCT4, SOX2, Nanog) and enhancing chemoresistance to adriamycin in TNBC cells. ERK activator PMA reversed these effects.","method":"Co-immunoprecipitation, co-localization (immunofluorescence), pharmacological rescue (PMA), western blot, IC50 assay","journal":"Molecular and cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus pharmacological rescue experiment, single lab","pmids":["29159771"],"is_preprint":false},{"year":2020,"finding":"CLDN6 interacts with and sequesters β-catenin in the cytoplasm, promoting its degradation and preventing nuclear translocation; this reduces SENP1 expression, prevents deSUMOylation of HIF-1α, and ultimately leads to HIF-1α degradation, forming a negative feedback loop with HIF-1α under hypoxic conditions in breast cancer.","method":"RNAi, ChIP assay, mRNA sequencing, KEGG pathway analysis, functional metastasis assays, clinical sample analysis","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP validation plus mechanistic epistasis through multiple pathway components, single lab","pmids":["32093760"],"is_preprint":false},{"year":2006,"finding":"The cytoplasmic tail domain of CLDN6 is required for correct membrane targeting; deletion of the tail (CDelta187) causes mislocalization of CLDN6 and other claudins (CLDN10, CLDN11, CLDN18) to the cytoplasm, activates a protein-unfolding pathway, and triggers postnatal epidermal hyperproliferation and aberrant differentiation in transgenic mice.","method":"Structure-function transgenic mouse model (tail-truncation mutant), immunofluorescence, histological analysis, western blot","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — structure-function mutagenesis in vivo with multiple biochemical and histological readouts, single lab","pmids":["16847338"],"is_preprint":false},{"year":2005,"finding":"Overexpression of CLDN6 in transgenic mouse epidermis perturbs epidermal differentiation, induces expression of CLDN5 and CLDN8 (not normally detectable), alters hair follicle differentiation (shorter anagen phase, altered hair type distribution), and disrupts expression of late differentiation markers (profilaggrin/filaggrin, loricrin, transglutaminase 3), establishing CLDN6 as a regulator of epidermal and follicular differentiation.","method":"Transgenic mouse overexpression (involucrin promoter), histological analysis, immunohistochemistry, western blot","journal":"Mechanisms of development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo transgenic model with multiple molecular readouts, single lab","pmids":["15908185"],"is_preprint":false},{"year":2017,"finding":"SMAD2 signaling upregulates DNMT1, which methylates the CLDN6 promoter to silence CLDN6 expression; blocking SMAD2 with SB431542 decreases DNMT1 binding to the CLDN6 promoter, reduces promoter methylation, increases CLDN6 protein, and suppresses EMT, migration and invasion; knockdown of CLDN6 abolishes these SB431542 effects.","method":"ChIP assay (DNMT1 binding to CLDN6 promoter), pharmacological inhibition (SB431542), CLDN6 siRNA knockdown, western blot, migration/invasion assays","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP assay plus rescue knockdown experiments establishing epistatic order, single lab","pmids":["28867761"],"is_preprint":false},{"year":2021,"finding":"CLDN6 interacts with TAZ (transcriptional co-activator with PDZ-binding motif) and reduces TAZ levels, thereby suppressing c-MYC transcription, reducing glucose uptake and lactate production, and inhibiting aerobic glycolysis-dependent proliferation in breast cancer cells.","method":"Co-immunoprecipitation, metabolomic analysis (lactate levels), western blot, in vitro and in vivo proliferation assays","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus metabolomic and functional assays, single lab","pmids":["35008557"],"is_preprint":false},{"year":2022,"finding":"CLDN6 suppresses ERK signaling to inhibit breast cancer cell proliferation via the ERK/Sp1/cyclin D1 axis, and inhibits migration and invasion via ERK/IL-8 and downstream CXCR2/FAK signaling; ERK activator PMA reversed all these CLDN6-mediated effects.","method":"Overexpression, pharmacological rescue (PMA), western blot, wound healing, transwell invasion assay","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological rescue experiments with multiple downstream readouts, single lab","pmids":["35752352"],"is_preprint":false},{"year":2023,"finding":"Through its PDZ-binding motif, CLDN6 interacts with JNK and upregulates JNK/c-Jun pathway; c-Jun transcriptionally upregulates WIP expression; WIP-dependent actin cytoskeleton assembly promotes autophagy, which in turn inhibits breast cancer metastasis; a positive feedback loop between CLDN6 and JNK/c-Jun was identified.","method":"Co-immunoprecipitation, immunofluorescence, ChIP, dual luciferase reporter assay, mRNA sequencing, phalloidin staining, western blot, in vivo lung metastasis models","journal":"Journal of experimental & clinical cancer research","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple orthogonal methods including Co-IP, ChIP, luciferase reporter, and in vivo rescue, single lab","pmids":["36935496"],"is_preprint":false},{"year":2024,"finding":"CLDN6 interacts with MAGI2 via its PDZ-binding motif to prevent KLF5 nuclear entry, thereby restraining SREBF1 transcription; reduced SREBP1 decreases de novo palmitic acid synthesis, impairing RAS palmitoylation and ESCRT-mediated plasma membrane localization of RAS, thus inhibiting oncogenic RAS activation and breast cancer progression.","method":"Co-immunoprecipitation, nuclear fractionation, immunofluorescence, IP-ABE (acyl-biotin exchange), ChIP, dual luciferase reporter assay, in vivo xenograft models, human palmitic acid and triglyceride assays","journal":"Cellular & molecular biology letters","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple orthogonal biochemical methods (Co-IP, IP-ABE, ChIP, luciferase) plus in vivo validation, single lab","pmids":["39169280"],"is_preprint":false},{"year":2023,"finding":"CLDN6 binds to ZO-1 through its PDZ-binding motif; this complex interacts with PTEN to regulate the AKT/MDM2 pathway, stabilize p53 by reducing ubiquitination, and promote p53 nuclear import, thereby inhibiting colorectal cancer cell proliferation.","method":"Co-immunoprecipitation, western blot, ubiquitination assay, nuclear fractionation, in vitro and in vivo proliferation assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of CLDN6-ZO-1-PTEN complex with mechanistic epistasis assays, single lab","pmids":["37852424"],"is_preprint":false},{"year":2025,"finding":"CLDN6 recruits PBK to the cell membrane via the endosomal pathway and binds the DLG1/PBK complex, promoting PBK degradation via the ubiquitin-proteasome system (UPS); reduced PBK activity decreases the AKT/GSK3β/FYN axis, enhancing nuclear export of NRF2 and triggering NRF2-mediated ferroptosis in breast cancer cells.","method":"Co-immunoprecipitation, western blot, immunofluorescence, in vitro and in vivo functional assays, UPS inhibition rescue","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and multiple functional assays with mechanistic validation, single lab","pmids":["39984471"],"is_preprint":false},{"year":2023,"finding":"BLK and SRC (but not FGR or HCK) directly bind to the C-terminal cytoplasmic domain of CLDN6 in a phosphotyrosine-independent manner (shown by pull-down with recombinant proteins); BLK and SRC are essential for CLDN6-triggered epithelial differentiation and expression of retinoic acid receptor target genes in F9 cells.","method":"Immunoprecipitation, pull-down assay with recombinant proteins, genetic knockout (F9:Cldn6:Blk-/- and F9:Cldn6:Src-/-), phenotypic comparison","journal":"Cells","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct binding shown with recombinant proteins plus genetic epistasis via double-knockout cell lines, single lab","pmids":["37443730"],"is_preprint":false},{"year":2024,"finding":"CLDN6 interacts with RIP1 (receptor interacting protein 1) and activates the RIP1/ASK1/JNK axis to suppress aerobic glycolysis and inhibit NSCLC cell proliferation, invasion, and migration; CLDN6 promoter is silenced by DNA methylation in NSCLC.","method":"Co-immunoprecipitation, methylation-specific PCR, gain-of-function overexpression, Seahorse metabolic assay, in vivo tumor growth assay","journal":"Journal of biochemical and molecular toxicology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP establishing CLDN6-RIP1 interaction plus functional metabolic assays, single lab","pmids":["38462752"],"is_preprint":false},{"year":2025,"finding":"CLDN6 interacts with LKB1 through its PDZ-binding motif, activating AMPK/ULK1 signaling and inducing protective autophagy; this protective autophagy promotes chemoresistance in breast cancer in response to adriamycin and paclitaxel. Chemotherapy increases CLDN6 expression via the ROS/GATA4 axis.","method":"Co-immunoprecipitation, western blot, autophagy assays, drug resistance assays, pharmacological inhibition rescue","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of CLDN6-LKB1 plus functional autophagy and resistance assays, single lab","pmids":["40959289"],"is_preprint":false},{"year":2018,"finding":"Knockdown of CLDN6 in endometrial carcinoma HEC-1B cells inhibits proliferation, migration, and invasion, and reduces phosphorylation of AKT, PI3K, and mTOR, placing CLDN6 upstream of the PI3K/AKT/mTOR signaling pathway in this cancer context.","method":"siRNA knockdown, CCK-8 proliferation assay, invasion/migration assays, western blot for pathway phosphorylation","journal":"OncoTargets and therapy","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single method (western blot for pathway activation) with no binding or rescue experiment, single lab","pmids":["30319275"],"is_preprint":false},{"year":2020,"finding":"Knockdown of CLDN6 in HepG2 hepatocellular carcinoma cells inhibits proliferation, migration, and invasion and reduces activation of the EGFR/AKT/mTOR signaling pathway; EGFR inhibitor AG1478 suppresses the pro-proliferative effects of CLDN6 overexpression.","method":"siRNA knockdown, overexpression, western blot for pathway activation, pharmacological inhibition (AG1478), in vitro functional assays","journal":"Cell biochemistry and function","confidence":"Low","confidence_rationale":"Tier 3 / Weak — western blot pathway inference plus pharmacological rescue, no direct binding shown, single lab","pmids":["32056244"],"is_preprint":false},{"year":2023,"finding":"CLDN6 knockdown in hepatocellular carcinoma cells decreases phosphorylation of JAK2 and STAT3, reduces anti-apoptotic Bcl-2, and increases cleaved caspase-3 and Bax, placing CLDN6 upstream of the JAK2/STAT3 anti-apoptotic pathway in HCC.","method":"siRNA knockdown, overexpression, western blot for pathway phosphorylation, apoptosis assays (flow cytometry), transwell assay","journal":"Translational cancer research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — western blot pathway inference only, no direct binding or rescue experiments, single lab","pmids":["37588735"],"is_preprint":false},{"year":2009,"finding":"CLDN6 gene expression in esophageal squamous cell carcinoma cell lines is silenced by DNA methylation of its promoter; treatment with the demethylating agent 5-aza-2'-deoxycytidine reduces methylation and restores CLDN6 mRNA expression.","method":"Methylation analysis, 5-aza-2'-deoxycytidine demethylation treatment, quantitative RT-PCR","journal":"Oncology reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct demethylation-restoration experiment linking methylation to silencing, replicated across multiple cell lines","pmids":["19288010"],"is_preprint":false},{"year":2026,"finding":"CLDN6 sequesters PDLIM2 at the cell membrane, reducing nuclear PDLIM2-mediated RelA (NF-κB) ubiquitination; accumulated RelA transcriptionally upregulates METTL14, which enhances m6A modification and degradation of SOX4 mRNA, attenuating PI3K/Akt signaling and triggering autophagic cell death in breast cancer.","method":"Co-immunoprecipitation, nuclear fractionation, western blot, m6A modification assay, ChIP, luciferase reporter, in vitro and in vivo functional assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus multiple orthogonal methods establishing mechanistic pathway, single lab","pmids":["42070760"],"is_preprint":false},{"year":2025,"finding":"CLDN6 was identified as a defining surface marker of columnar trophoblast (bridging villous and extravillous compartments) during human chorion development; prospective isolation of CLDN6+ cells revealed their capacity to reacquire a proliferative villous state and, under directed cues, generate both syncytial and extravillous fates.","method":"Single-cell transcriptomics, spatial transcriptomics, prospective cell isolation using CLDN6 as surface marker, directed differentiation assays","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — CLDN6 used as marker for cell isolation, functional potential assessed in directed culture, preprint not peer-reviewed, single study","pmids":[],"is_preprint":true}],"current_model":"CLDN6 is a tetraspan tight junction protein whose C-terminal cytoplasmic tail (containing a PDZ-binding motif) is required for correct membrane targeting; through this motif it forms complexes with multiple scaffold and signaling proteins—including LATS1/2 (suppressing Hippo/YAP1 signaling), AF-6/afadin (suppressing ERK), ZO-1/PTEN (stabilizing p53 via AKT/MDM2), MAGI2 (blocking KLF5/SREBP1-driven RAS palmitoylation), LKB1 (activating AMPK/ULK1-dependent autophagy), RIP1 (activating ASK1/JNK to suppress glycolysis), DLG1/PBK (promoting ferroptosis via NRF2), TAZ (suppressing c-MYC-driven glycolysis), and SRC-family kinases BLK and SRC (mediating epithelial differentiation)—and its promoter is silenced by DNMT1-mediated DNA methylation downstream of TGFβ/SMAD2 signaling, with its expression producing context-dependent tumor-suppressive or oncogenic outcomes depending on the cancer type."},"narrative":{"mechanistic_narrative":"CLDN6 is a tetraspan tight junction membrane protein that functions as a context-dependent signaling hub, coupling its C-terminal cytoplasmic tail to scaffold and kinase partners to control proliferation, differentiation, metabolism, and cell death—most extensively characterized in breast cancer but also acting in gastric, hepatocellular, colorectal, and lung tumors [PMID:39169280, PMID:37443730, PMID:31827075]. Correct membrane targeting of CLDN6 depends on its cytoplasmic tail, whose deletion mislocalizes CLDN6 and partner claudins and disrupts epidermal and hair-follicle differentiation in vivo [PMID:16847338, PMID:15908185]. Many of its signaling functions are routed through a C-terminal PDZ-binding motif that docks scaffold proteins: CLDN6 binds ZO-1 to assemble a PTEN-containing complex that stabilizes p53 by restraining AKT/MDM2-mediated ubiquitination [PMID:37852424], binds MAGI2 to block KLF5/SREBF1-driven palmitate synthesis and thereby impair oncogenic RAS palmitoylation and membrane localization [PMID:39169280], and binds LKB1 to activate AMPK/ULK1-dependent autophagy [PMID:40959289]. CLDN6 also engages SRC-family kinases BLK and SRC directly through its C-terminal domain in a phosphotyrosine-independent manner, and these kinases are required for CLDN6-triggered epithelial differentiation [PMID:37443730]. A recurring tumor-suppressive theme is restraint of growth-promoting kinase cascades and reprogramming of metabolism: CLDN6 suppresses ERK signaling via AF-6/afadin and the ERK/Sp1/cyclin D1 and ERK/IL-8 axes [PMID:29159771, PMID:35752352], activates ASK1- and RIP1/JNK-dependent pathways to drive apoptosis and suppress aerobic glycolysis [PMID:27035750, PMID:38462752], and lowers TAZ to dampen c-MYC-driven glycolysis [PMID:35008557]. CLDN6 expression is silenced by promoter DNA methylation across esophageal, lung, and other carcinomas, with TGFβ/SMAD2 signaling driving DNMT1 recruitment to the CLDN6 promoter [PMID:19288010, PMID:28867761, PMID:38462752]. Its activity is not uniformly suppressive: by interacting with LATS1/2 or a TJP2 complex, CLDN6 can promote YAP1 nuclear entry to drive EMT and lineage shifts, producing oncogenic outcomes in gastric and hepatocellular carcinoma [PMID:31827075, PMID:33536280].","teleology":[{"year":2006,"claim":"Established that the CLDN6 cytoplasmic tail is required for correct membrane targeting and that CLDN6 dosage and localization control epidermal differentiation, defining its first in vivo physiological role.","evidence":"Tail-truncation and overexpression transgenic mouse models with histology, immunofluorescence, and differentiation-marker western blots","pmids":["16847338","15908185"],"confidence":"High","gaps":["Does not define the molecular partners bound by the tail in epidermis","Mechanism linking mislocalization to the unfolding-protein response not resolved"]},{"year":2009,"claim":"Showed that loss of CLDN6 in carcinoma is driven by promoter DNA methylation, establishing an epigenetic silencing mechanism for its downregulation.","evidence":"Promoter methylation analysis and 5-aza-2'-deoxycytidine demethylation-restoration in esophageal squamous carcinoma cell lines","pmids":["19288010"],"confidence":"Medium","gaps":["Did not identify the upstream signal directing methylation","Functional consequence of restored CLDN6 not tested here"]},{"year":2017,"claim":"Connected an upstream signaling input to CLDN6 silencing by showing TGFβ/SMAD2 drives DNMT1 binding and methylation of the CLDN6 promoter, placing CLDN6 loss within EMT programs.","evidence":"ChIP for DNMT1 promoter occupancy, SB431542 inhibition, and CLDN6 siRNA rescue in cancer cells","pmids":["28867761"],"confidence":"Medium","gaps":["Does not establish which cancer contexts depend on this axis","SMAD2-independent silencing routes not excluded"]},{"year":2017,"claim":"Demonstrated that CLDN6 physically engages signaling and scaffold partners (p53, AF-6) to control chemoresistance and ERK signaling, opening the model of CLDN6 as a membrane-anchored signaling regulator rather than a passive junction protein.","evidence":"Co-IP, co-localization, RNAi/overexpression, and pharmacological rescue (PMA) in breast cancer cells","pmids":["29116019","29159771"],"confidence":"Medium","gaps":["Direct versus indirect nature of the p53 interaction not structurally resolved","Whether the PDZ motif mediates these interactions not tested in these studies"]},{"year":2016,"claim":"Placed CLDN6 upstream of an ASK1-p38/JNK apoptotic cascade, linking CLDN6 restoration to stress-kinase-driven cell death.","evidence":"Stable transfection, ASK1 pharmacological inhibition (TRX1), TUNEL, and apoptosis-marker western blots in MCF-7 cells","pmids":["27035750"],"confidence":"Medium","gaps":["No direct CLDN6-ASK1 binding shown","Mechanism reducing ASK1 Ser967 phosphorylation unresolved"]},{"year":2019,"claim":"Revealed opposing roles for CLDN6 in Hippo signaling—suppressing LATS1/2 to promote oncogenic YAP1/EMT in gastric cancer versus inducing autophagy downstream of ERβ in breast cancer—establishing its context-dependent output.","evidence":"Co-IP and phosphorylation assays for LATS1/2-YAP1; ChIP, luciferase, beclin1-knockdown rescue, and xenografts for ERβ/CLDN6/autophagy","pmids":["31827075","31412908"],"confidence":"Medium","gaps":["What determines tumor-suppressive versus oncogenic Hippo output not defined","Direct LATS1/2 binding interface not mapped"]},{"year":2020,"claim":"Extended CLDN6's regulatory reach to hypoxia and Wnt signaling by showing it sequesters β-catenin to drive HIF-1α degradation through a SENP1-dependent feedback loop.","evidence":"RNAi, ChIP, mRNA sequencing, and metastasis assays with clinical samples in breast cancer","pmids":["32093760"],"confidence":"Medium","gaps":["Direct CLDN6-β-catenin binding interface not defined","Generality beyond breast cancer untested"]},{"year":2021,"claim":"Defined CLDN6 as a metabolic regulator by showing TJP2-dependent YAP1 activation and TAZ-dependent c-MYC suppression of glycolysis, linking junctional partners to tumor energy metabolism and lineage.","evidence":"Co-IP, metabolomic lactate/glucose measurements, and functional assays in hepatocellular and breast cancer cells","pmids":["33536280","35008557"],"confidence":"Medium","gaps":["How CLDN6 chooses between TAZ suppression and TJP2/YAP1 activation unresolved","TAZ degradation mechanism not defined"]},{"year":2023,"claim":"Anchored CLDN6 signaling to its PDZ-binding motif and SRC-family kinases, showing direct, phosphotyrosine-independent binding of BLK and SRC required for differentiation and PDZ-motif-dependent assembly of ZO-1/PTEN and JNK/c-Jun complexes.","evidence":"Recombinant-protein pull-downs and double-knockout F9 cells for BLK/SRC; Co-IP, ChIP, luciferase, and in vivo metastasis models for ZO-1/PTEN and JNK/c-Jun","pmids":["37443730","37852424","36935496"],"confidence":"High","gaps":["Structural basis of PDZ-partner selectivity not determined","Whether SRC-family binding and PDZ-scaffold binding are mutually exclusive unknown"]},{"year":2024,"claim":"Expanded the CLDN6 scaffold network to metabolic and stress-kinase control, with MAGI2 binding restraining SREBF1/RAS palmitoylation and RIP1 binding activating ASK1/JNK to suppress glycolysis in lung cancer.","evidence":"Co-IP, IP-ABE acyl-biotin exchange, ChIP, and xenografts (breast); Co-IP, methylation-specific PCR, and Seahorse assays (NSCLC)","pmids":["39169280","38462752"],"confidence":"Medium","gaps":["RIP1 interaction shown by Co-IP without direct binding validation","Cross-talk between these parallel CLDN6 outputs unmapped"]},{"year":2025,"claim":"Established CLDN6 as a controller of autophagy and ferroptosis through LKB1/AMPK/ULK1 and DLG1/PBK/NRF2 axes, showing both protective (chemoresistance) and lethal (ferroptosis) outcomes depending on partner engagement.","evidence":"Co-IP, autophagy and ferroptosis assays, UPS-inhibition rescue, and in vivo models in breast cancer","pmids":["40959289","39984471"],"confidence":"Medium","gaps":["What dictates protective versus lethal autophagy outcome unresolved","PBK recruitment via the endosomal pathway mechanistically incomplete"]},{"year":null,"claim":"It remains unresolved what molecular switch determines whether CLDN6 acts as a tumor suppressor or oncogene across tissues, and whether a unifying biochemical rule governs PDZ-partner selection and the divergent downstream outcomes.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of CLDN6 PDZ-motif/partner complexes","Context-determining factors for opposing Hippo, autophagy, and metabolic outputs unknown","Native tight-junction barrier function relative to signaling role not directly compared"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[13,14,16,18]},{"term_id":"GO:0140313","term_label":"molecular sequestering activity","supporting_discovery_ids":[6,4,15,23]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[7,8]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[7,15,23]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[4,6]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[15]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,5,11,14]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[2,12,18,23]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3,15,23]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[10,13,17]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[7,8,16]}],"complexes":[],"partners":["LATS1","TJP2","AF-6","MAGI2","LKB1","RIP1","TAZ","SRC"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P56747","full_name":"Claudin-6","aliases":["Skullin"],"length_aa":220,"mass_kda":23.3,"function":"Plays a major role in tight junction-specific obliteration of the intercellular space (Microbial infection) Acts as a receptor for hepatitis C virus (HCV) entry into hepatic cells","subcellular_location":"Cell junction, tight junction; Cell membrane","url":"https://www.uniprot.org/uniprotkb/P56747/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CLDN6","classification":"Not Classified","n_dependent_lines":153,"n_total_lines":1208,"dependency_fraction":0.12665562913907286},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CLDN6","total_profiled":1310},"omim":[{"mim_id":"615799","title":"CLAUDIN 9; CLDN9","url":"https://www.omim.org/entry/615799"},{"mim_id":"615798","title":"CLAUDIN 6; CLDN6","url":"https://www.omim.org/entry/615798"},{"mim_id":"609532","title":"HEPATITIS C VIRUS, SUSCEPTIBILITY TO","url":"https://www.omim.org/entry/609532"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":1.0},{"tissue":"pancreas","ntpm":1.0}],"url":"https://www.proteinatlas.org/search/CLDN6"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P56747","domains":[{"cath_id":"1.20.140.150","chopping":"10-28_73-185","consensus_level":"high","plddt":90.0414,"start":10,"end":185}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P56747","model_url":"https://alphafold.ebi.ac.uk/files/AF-P56747-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P56747-F1-predicted_aligned_error_v6.png","plddt_mean":80.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CLDN6","jax_strain_url":"https://www.jax.org/strain/search?query=CLDN6"},"sequence":{"accession":"P56747","fasta_url":"https://rest.uniprot.org/uniprotkb/P56747.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P56747/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P56747"}},"corpus_meta":[{"pmid":"37872225","id":"PMC_37872225","title":"CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial.","date":"2023","source":"Nature medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37872225","citation_count":221,"is_preprint":false},{"pmid":"31412908","id":"PMC_31412908","title":"Estrogen receptor β inhibits breast cancer cells migration and invasion through CLDN6-mediated autophagy.","date":"2019","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/31412908","citation_count":117,"is_preprint":false},{"pmid":"31827075","id":"PMC_31827075","title":"CLDN6 promotes tumor progression through the YAP1-snail1 axis in gastric cancer.","date":"2019","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/31827075","citation_count":75,"is_preprint":false},{"pmid":"33536280","id":"PMC_33536280","title":"Targeting tumor lineage plasticity in hepatocellular carcinoma using an anti-CLDN6 antibody-drug conjugate.","date":"2021","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33536280","citation_count":64,"is_preprint":false},{"pmid":"29116019","id":"PMC_29116019","title":"CLDN6 promotes chemoresistance through GSTP1 in human breast cancer.","date":"2017","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/29116019","citation_count":60,"is_preprint":false},{"pmid":"15908185","id":"PMC_15908185","title":"Delayed epidermal permeability barrier formation and hair follicle aberrations in Inv-Cldn6 mice.","date":"2005","source":"Mechanisms of development","url":"https://pubmed.ncbi.nlm.nih.gov/15908185","citation_count":54,"is_preprint":false},{"pmid":"19288010","id":"PMC_19288010","title":"Methylation of CLDN6, FBN2, RBP1, RBP4, TFPI2, and TMEFF2 in esophageal squamous cell carcinoma.","date":"2009","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/19288010","citation_count":49,"is_preprint":false},{"pmid":"27035750","id":"PMC_27035750","title":"CLDN6-induced apoptosis via regulating ASK1-p38/JNK signaling in breast cancer MCF-7 cells.","date":"2016","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/27035750","citation_count":43,"is_preprint":false},{"pmid":"36884217","id":"PMC_36884217","title":"Preclinical Efficacy of the Antibody-Drug Conjugate CLDN6-23-ADC for the Treatment of CLDN6-Positive Solid Tumors.","date":"2023","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/36884217","citation_count":40,"is_preprint":false},{"pmid":"16847338","id":"PMC_16847338","title":"Role of the Cldn6 cytoplasmic tail domain in membrane targeting and epidermal differentiation in vivo.","date":"2006","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/16847338","citation_count":40,"is_preprint":false},{"pmid":"32093760","id":"PMC_32093760","title":"A SUMOylation-dependent HIF-1α/CLDN6 negative feedback mitigates hypoxia-induced breast cancer metastasis.","date":"2020","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/32093760","citation_count":39,"is_preprint":false},{"pmid":"34948213","id":"PMC_34948213","title":"CLDN6: From Traditional Barrier Function to Emerging Roles in Cancers.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34948213","citation_count":38,"is_preprint":false},{"pmid":"30319275","id":"PMC_30319275","title":"Knockdown of CLDN6 inhibits cell proliferation and migration via PI3K/AKT/mTOR signaling pathway in endometrial carcinoma cell line HEC-1-B.","date":"2018","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/30319275","citation_count":33,"is_preprint":false},{"pmid":"29159771","id":"PMC_29159771","title":"CLDN6 enhances chemoresistance to ADM via AF-6/ERKs pathway in TNBC cell line MDAMB231.","date":"2017","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29159771","citation_count":31,"is_preprint":false},{"pmid":"35051418","id":"PMC_35051418","title":"KHDRBS3 promotes paclitaxel resistance and induces glycolysis through modulated MIR17HG/CLDN6 signaling in epithelial ovarian cancer.","date":"2022","source":"Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35051418","citation_count":30,"is_preprint":false},{"pmid":"36935496","id":"PMC_36935496","title":"CLDN6 inhibits breast cancer metastasis through WIP-dependent actin cytoskeleton-mediated autophagy.","date":"2023","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/36935496","citation_count":28,"is_preprint":false},{"pmid":"28867761","id":"PMC_28867761","title":"SMAD2 Inactivation Inhibits CLDN6 Methylation to Suppress Migration and Invasion of Breast Cancer Cells.","date":"2017","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/28867761","citation_count":27,"is_preprint":false},{"pmid":"34249076","id":"PMC_34249076","title":"Association of CLDN6 and CLDN10 With Immune Microenvironment in Ovarian Cancer: A Study of the Claudin Family.","date":"2021","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34249076","citation_count":24,"is_preprint":false},{"pmid":"39169280","id":"PMC_39169280","title":"CLDN6 inhibits breast cancer growth and metastasis through SREBP1-mediated RAS palmitoylation.","date":"2024","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/39169280","citation_count":23,"is_preprint":false},{"pmid":"32056244","id":"PMC_32056244","title":"Downregulation of CLDN6 inhibits cell proliferation, migration, and invasion via regulating EGFR/AKT/mTOR signalling pathway in hepatocellular carcinoma.","date":"2020","source":"Cell biochemistry and function","url":"https://pubmed.ncbi.nlm.nih.gov/32056244","citation_count":22,"is_preprint":false},{"pmid":"35008557","id":"PMC_35008557","title":"CLDN6 Suppresses c-MYC-Mediated Aerobic Glycolysis to Inhibit Proliferation by TAZ in Breast Cancer.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35008557","citation_count":20,"is_preprint":false},{"pmid":"34405008","id":"PMC_34405008","title":"The Expression of CLDN6 in Hepatocellular Carcinoma Tissue and the Effects of CLDN6 on Biological Phenotypes of Hepatocellular Carcinoma Cells.","date":"2021","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/34405008","citation_count":19,"is_preprint":false},{"pmid":"39401967","id":"PMC_39401967","title":"SAIL66, a next generation CLDN6-targeting T-cell engager, demonstrates potent antitumor efficacy through dual binding to CD3/CD137.","date":"2024","source":"Journal for immunotherapy of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/39401967","citation_count":15,"is_preprint":false},{"pmid":"35752352","id":"PMC_35752352","title":"CLDN6 inhibits breast cancer cell malignant behavior by suppressing ERK signaling.","date":"2022","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/35752352","citation_count":15,"is_preprint":false},{"pmid":"36991316","id":"PMC_36991316","title":"Targeting CLDN6 in germ cell tumors by an antibody-drug-conjugate and studying therapy resistance of yolk-sac tumors to identify and screen specific therapeutic options.","date":"2023","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/36991316","citation_count":15,"is_preprint":false},{"pmid":"32170581","id":"PMC_32170581","title":"Tight Junction-Related CLDN5 and CLDN6 Genes, and Gap Junction-Related GJB6 and GJB7 Genes Are Somatically Mutated in Gastric and Colorectal Cancers.","date":"2020","source":"Pathology oncology research : POR","url":"https://pubmed.ncbi.nlm.nih.gov/32170581","citation_count":14,"is_preprint":false},{"pmid":"33862296","id":"PMC_33862296","title":"Effects of the Tight Junction Protein CLDN6 on Cell Migration and Invasion in High-Grade Meningioma.","date":"2021","source":"World neurosurgery","url":"https://pubmed.ncbi.nlm.nih.gov/33862296","citation_count":9,"is_preprint":false},{"pmid":"35701678","id":"PMC_35701678","title":"The expression and the tumor suppressor role of CLDN6 in colon cancer.","date":"2022","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35701678","citation_count":8,"is_preprint":false},{"pmid":"37443730","id":"PMC_37443730","title":"The Src-Family Kinases SRC and BLK Contribute to the CLDN6-Adhesion Signaling.","date":"2023","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/37443730","citation_count":7,"is_preprint":false},{"pmid":"32782677","id":"PMC_32782677","title":"CLDN6-mediates SB431542 action through MMPs to regulate the invasion, migration, and EMT of breast cancer cells.","date":"2020","source":"International journal of clinical and experimental pathology","url":"https://pubmed.ncbi.nlm.nih.gov/32782677","citation_count":7,"is_preprint":false},{"pmid":"37852424","id":"PMC_37852424","title":"CLDN6 inhibits colorectal cancer proliferation dependent on restraining p53 ubiquitination via ZO-1/PTEN axis.","date":"2023","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/37852424","citation_count":5,"is_preprint":false},{"pmid":"37588735","id":"PMC_37588735","title":"Downregulation of CLDN6 inhibits cell migration and invasion and promotes apoptosis by regulation of the JAK2/STAT3 signaling pathway in hepatocellular carcinoma.","date":"2023","source":"Translational cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/37588735","citation_count":5,"is_preprint":false},{"pmid":"39984471","id":"PMC_39984471","title":"CLDN6 triggers NRF2-mediated ferroptosis through recruiting DLG1/PBK complex in breast cancer.","date":"2025","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/39984471","citation_count":4,"is_preprint":false},{"pmid":"38462752","id":"PMC_38462752","title":"CLDN6 inhibited cellular biological function of nonsmall cell lung cancer cells through suppressing aerobic glycolysis via the RIP1/ASK1/JNK axis.","date":"2024","source":"Journal of biochemical and molecular toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/38462752","citation_count":4,"is_preprint":false},{"pmid":"37566248","id":"PMC_37566248","title":"CLDN6 Suppresses Migration and Invasion of MCF-7 and SKBR-3 Breast Cancer Cells by Blocking the SMAD/Snail/MMP-2/9 Axis.","date":"2023","source":"Bulletin of experimental biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37566248","citation_count":4,"is_preprint":false},{"pmid":"40959289","id":"PMC_40959289","title":"CLDN6 induces chemoresistance through protective autophagy in breast cancer.","date":"2025","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40959289","citation_count":3,"is_preprint":false},{"pmid":"40380180","id":"PMC_40380180","title":"Inhibition of DLK1 regulates AT2 differentiation and alleviates established pulmonary fibrosis by upregulating TTF-1/CLDN6.","date":"2025","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/40380180","citation_count":2,"is_preprint":false},{"pmid":"41628300","id":"PMC_41628300","title":"CLDN6 Expression Plasticity in Ovarian Cancer: Insights into Therapeutic Optimization for CLDN6-Targeted Immunotherapy.","date":"2026","source":"Cancer research communications","url":"https://pubmed.ncbi.nlm.nih.gov/41628300","citation_count":1,"is_preprint":false},{"pmid":"41882748","id":"PMC_41882748","title":"A novel CLDN6 nanobody-based bispecific T-cell engager delivered by self-amplifying RNA platform exhibits potent antitumor efficacy.","date":"2026","source":"Journal of nanobiotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/41882748","citation_count":0,"is_preprint":false},{"pmid":"42259433","id":"PMC_42259433","title":"CLDN6 in Cancer: Biology, Clinical Significance, and Emerging Therapeutic Strategies.","date":"2026","source":"Pharmacological research","url":"https://pubmed.ncbi.nlm.nih.gov/42259433","citation_count":0,"is_preprint":false},{"pmid":"41923292","id":"PMC_41923292","title":"The Functional Role and Molecular Characterization of the Therapeutic Target CLDN6 in Germ Cell Tumors.","date":"2026","source":"Andrology","url":"https://pubmed.ncbi.nlm.nih.gov/41923292","citation_count":0,"is_preprint":false},{"pmid":"41804857","id":"PMC_41804857","title":"Overcoming claudin family homology: discovery of ARC101, a highly potent CLDN6-specific T-cell engager with a novel CD3 binder for ovarian adenocarcinoma.","date":"2026","source":"mAbs","url":"https://pubmed.ncbi.nlm.nih.gov/41804857","citation_count":0,"is_preprint":false},{"pmid":"42070760","id":"PMC_42070760","title":"CLDN6 inhibits breast cancer growth by inducing autophagic cell death through SOX4 m6A modification.","date":"2026","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/42070760","citation_count":0,"is_preprint":false},{"pmid":"41569314","id":"PMC_41569314","title":"Anti-cancer effects of carvacrol on NUF2, CASP3 and CLDN6 expression in T47D breast cancer cells.","date":"2026","source":"Naunyn-Schmiedeberg's archives of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41569314","citation_count":0,"is_preprint":false},{"pmid":"42102523","id":"PMC_42102523","title":"Expression of the antibody-drug conjugate targets TROP2, CLDN6, B7-H3, and DLL3 in mesonephric-like adenocarcinoma of the female genital tract.","date":"2026","source":"Gynecologic oncology","url":"https://pubmed.ncbi.nlm.nih.gov/42102523","citation_count":0,"is_preprint":false},{"pmid":"41835342","id":"PMC_41835342","title":"Evaluating Claudin-6 and isochromosome 12p in the progression from germ cell neoplasia in situ to primary testicular germ cell tumor and post-chemotherapy teratoma: implications for CLDN6-targeted therapies.","date":"2026","source":"Therapeutic advances in medical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/41835342","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.18.688276","title":"Reconstructing the emergence of the human chorion via HIPPO-mediated trophoblast induction","date":"2025-11-18","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.18.688276","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":27874,"output_tokens":6112,"usd":0.087651,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":14892,"output_tokens":4475,"usd":0.093168,"stage2_stop_reason":"end_turn"},"total_usd":0.180819,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2019,\n      \"finding\": \"CLDN6 reduces phosphorylation of LATS1/2 and YAP1 by directly interacting with LATS1/2 in the Hippo signaling pathway, thereby promoting YAP1 nuclear entry; nuclear YAP1 then interacts with Snail1 to drive EMT and enhance gastric cancer cell invasiveness.\",\n      \"method\": \"Co-immunoprecipitation, western blot (phosphorylation assays), in vitro and in vivo functional assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP showing CLDN6-LATS1/2 interaction plus downstream phosphorylation assays, single lab\",\n      \"pmids\": [\"31827075\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CLDN6 interacts with TJP2 (tight junction protein 2), and this CLDN6/TJP2 complex activates YAP1 via the Hippo signaling pathway, inducing phenotypic shift of hepatocellular carcinoma cells from hepatic to biliary lineage and conferring sorafenib resistance.\",\n      \"method\": \"Co-immunoprecipitation, functional cell line assays, overexpression studies\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of CLDN6/TJP2 complex with functional validation, single lab\",\n      \"pmids\": [\"33536280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ERβ transcriptionally upregulates CLDN6 expression (confirmed by ChIP and dual luciferase reporter assays), and CLDN6 in turn positively regulates beclin1 to induce beclin1-dependent autophagy, thereby inhibiting breast cancer cell migration and invasion.\",\n      \"method\": \"ChIP assay, dual luciferase reporter assay, western blot, immunofluorescence, transmission electron microscopy, xenograft mouse models\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — ChIP + dual luciferase reporter + rescue experiments with beclin1 knockdown, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"31412908\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CLDN6 restoration in MCF-7 breast cancer cells decreases ASK1 phosphorylation at Ser967, activating downstream JNK and p38 kinase; inhibition of ASK1 with TRX1 suppressed JNK/p38 activation, reversed apoptosis, and increased Bcl-2/Bax ratio and reduced caspase-3 cleavage, placing CLDN6 upstream of the ASK1-p38/JNK apoptotic pathway.\",\n      \"method\": \"Stable transfection, pharmacological inhibition (TRX1), TUNEL staining, DNA ladder, western blot, colony formation assay\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple functional assays plus pharmacological rescue, single lab\",\n      \"pmids\": [\"27035750\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CLDN6 interacts with p53 and promotes translocation of p53 from nucleus to cytoplasm; this nuclear exclusion of p53 upregulates GSTP1 expression and GST enzyme activity, conferring chemoresistance to adriamycin, 5-FU, and cisplatin in breast cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, RNAi knockdown/overexpression, CCK-8 cytotoxicity assay, GST activity kit, western blot\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of CLDN6-p53, functional rescue with GSTP1 manipulation, single lab\",\n      \"pmids\": [\"29116019\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CLDN6 co-localizes and physically interacts with AF-6 (afadin); CLDN6 overexpression increases AF-6 expression and suppresses ERK signaling activation, upregulating cancer stem cell markers (OCT4, SOX2, Nanog) and enhancing chemoresistance to adriamycin in TNBC cells. ERK activator PMA reversed these effects.\",\n      \"method\": \"Co-immunoprecipitation, co-localization (immunofluorescence), pharmacological rescue (PMA), western blot, IC50 assay\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus pharmacological rescue experiment, single lab\",\n      \"pmids\": [\"29159771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CLDN6 interacts with and sequesters β-catenin in the cytoplasm, promoting its degradation and preventing nuclear translocation; this reduces SENP1 expression, prevents deSUMOylation of HIF-1α, and ultimately leads to HIF-1α degradation, forming a negative feedback loop with HIF-1α under hypoxic conditions in breast cancer.\",\n      \"method\": \"RNAi, ChIP assay, mRNA sequencing, KEGG pathway analysis, functional metastasis assays, clinical sample analysis\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP validation plus mechanistic epistasis through multiple pathway components, single lab\",\n      \"pmids\": [\"32093760\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The cytoplasmic tail domain of CLDN6 is required for correct membrane targeting; deletion of the tail (CDelta187) causes mislocalization of CLDN6 and other claudins (CLDN10, CLDN11, CLDN18) to the cytoplasm, activates a protein-unfolding pathway, and triggers postnatal epidermal hyperproliferation and aberrant differentiation in transgenic mice.\",\n      \"method\": \"Structure-function transgenic mouse model (tail-truncation mutant), immunofluorescence, histological analysis, western blot\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — structure-function mutagenesis in vivo with multiple biochemical and histological readouts, single lab\",\n      \"pmids\": [\"16847338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Overexpression of CLDN6 in transgenic mouse epidermis perturbs epidermal differentiation, induces expression of CLDN5 and CLDN8 (not normally detectable), alters hair follicle differentiation (shorter anagen phase, altered hair type distribution), and disrupts expression of late differentiation markers (profilaggrin/filaggrin, loricrin, transglutaminase 3), establishing CLDN6 as a regulator of epidermal and follicular differentiation.\",\n      \"method\": \"Transgenic mouse overexpression (involucrin promoter), histological analysis, immunohistochemistry, western blot\",\n      \"journal\": \"Mechanisms of development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo transgenic model with multiple molecular readouts, single lab\",\n      \"pmids\": [\"15908185\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SMAD2 signaling upregulates DNMT1, which methylates the CLDN6 promoter to silence CLDN6 expression; blocking SMAD2 with SB431542 decreases DNMT1 binding to the CLDN6 promoter, reduces promoter methylation, increases CLDN6 protein, and suppresses EMT, migration and invasion; knockdown of CLDN6 abolishes these SB431542 effects.\",\n      \"method\": \"ChIP assay (DNMT1 binding to CLDN6 promoter), pharmacological inhibition (SB431542), CLDN6 siRNA knockdown, western blot, migration/invasion assays\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP assay plus rescue knockdown experiments establishing epistatic order, single lab\",\n      \"pmids\": [\"28867761\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CLDN6 interacts with TAZ (transcriptional co-activator with PDZ-binding motif) and reduces TAZ levels, thereby suppressing c-MYC transcription, reducing glucose uptake and lactate production, and inhibiting aerobic glycolysis-dependent proliferation in breast cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, metabolomic analysis (lactate levels), western blot, in vitro and in vivo proliferation assays\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus metabolomic and functional assays, single lab\",\n      \"pmids\": [\"35008557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CLDN6 suppresses ERK signaling to inhibit breast cancer cell proliferation via the ERK/Sp1/cyclin D1 axis, and inhibits migration and invasion via ERK/IL-8 and downstream CXCR2/FAK signaling; ERK activator PMA reversed all these CLDN6-mediated effects.\",\n      \"method\": \"Overexpression, pharmacological rescue (PMA), western blot, wound healing, transwell invasion assay\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological rescue experiments with multiple downstream readouts, single lab\",\n      \"pmids\": [\"35752352\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Through its PDZ-binding motif, CLDN6 interacts with JNK and upregulates JNK/c-Jun pathway; c-Jun transcriptionally upregulates WIP expression; WIP-dependent actin cytoskeleton assembly promotes autophagy, which in turn inhibits breast cancer metastasis; a positive feedback loop between CLDN6 and JNK/c-Jun was identified.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, ChIP, dual luciferase reporter assay, mRNA sequencing, phalloidin staining, western blot, in vivo lung metastasis models\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple orthogonal methods including Co-IP, ChIP, luciferase reporter, and in vivo rescue, single lab\",\n      \"pmids\": [\"36935496\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CLDN6 interacts with MAGI2 via its PDZ-binding motif to prevent KLF5 nuclear entry, thereby restraining SREBF1 transcription; reduced SREBP1 decreases de novo palmitic acid synthesis, impairing RAS palmitoylation and ESCRT-mediated plasma membrane localization of RAS, thus inhibiting oncogenic RAS activation and breast cancer progression.\",\n      \"method\": \"Co-immunoprecipitation, nuclear fractionation, immunofluorescence, IP-ABE (acyl-biotin exchange), ChIP, dual luciferase reporter assay, in vivo xenograft models, human palmitic acid and triglyceride assays\",\n      \"journal\": \"Cellular & molecular biology letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple orthogonal biochemical methods (Co-IP, IP-ABE, ChIP, luciferase) plus in vivo validation, single lab\",\n      \"pmids\": [\"39169280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CLDN6 binds to ZO-1 through its PDZ-binding motif; this complex interacts with PTEN to regulate the AKT/MDM2 pathway, stabilize p53 by reducing ubiquitination, and promote p53 nuclear import, thereby inhibiting colorectal cancer cell proliferation.\",\n      \"method\": \"Co-immunoprecipitation, western blot, ubiquitination assay, nuclear fractionation, in vitro and in vivo proliferation assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of CLDN6-ZO-1-PTEN complex with mechanistic epistasis assays, single lab\",\n      \"pmids\": [\"37852424\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CLDN6 recruits PBK to the cell membrane via the endosomal pathway and binds the DLG1/PBK complex, promoting PBK degradation via the ubiquitin-proteasome system (UPS); reduced PBK activity decreases the AKT/GSK3β/FYN axis, enhancing nuclear export of NRF2 and triggering NRF2-mediated ferroptosis in breast cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, western blot, immunofluorescence, in vitro and in vivo functional assays, UPS inhibition rescue\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and multiple functional assays with mechanistic validation, single lab\",\n      \"pmids\": [\"39984471\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"BLK and SRC (but not FGR or HCK) directly bind to the C-terminal cytoplasmic domain of CLDN6 in a phosphotyrosine-independent manner (shown by pull-down with recombinant proteins); BLK and SRC are essential for CLDN6-triggered epithelial differentiation and expression of retinoic acid receptor target genes in F9 cells.\",\n      \"method\": \"Immunoprecipitation, pull-down assay with recombinant proteins, genetic knockout (F9:Cldn6:Blk-/- and F9:Cldn6:Src-/-), phenotypic comparison\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct binding shown with recombinant proteins plus genetic epistasis via double-knockout cell lines, single lab\",\n      \"pmids\": [\"37443730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CLDN6 interacts with RIP1 (receptor interacting protein 1) and activates the RIP1/ASK1/JNK axis to suppress aerobic glycolysis and inhibit NSCLC cell proliferation, invasion, and migration; CLDN6 promoter is silenced by DNA methylation in NSCLC.\",\n      \"method\": \"Co-immunoprecipitation, methylation-specific PCR, gain-of-function overexpression, Seahorse metabolic assay, in vivo tumor growth assay\",\n      \"journal\": \"Journal of biochemical and molecular toxicology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP establishing CLDN6-RIP1 interaction plus functional metabolic assays, single lab\",\n      \"pmids\": [\"38462752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CLDN6 interacts with LKB1 through its PDZ-binding motif, activating AMPK/ULK1 signaling and inducing protective autophagy; this protective autophagy promotes chemoresistance in breast cancer in response to adriamycin and paclitaxel. Chemotherapy increases CLDN6 expression via the ROS/GATA4 axis.\",\n      \"method\": \"Co-immunoprecipitation, western blot, autophagy assays, drug resistance assays, pharmacological inhibition rescue\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of CLDN6-LKB1 plus functional autophagy and resistance assays, single lab\",\n      \"pmids\": [\"40959289\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Knockdown of CLDN6 in endometrial carcinoma HEC-1B cells inhibits proliferation, migration, and invasion, and reduces phosphorylation of AKT, PI3K, and mTOR, placing CLDN6 upstream of the PI3K/AKT/mTOR signaling pathway in this cancer context.\",\n      \"method\": \"siRNA knockdown, CCK-8 proliferation assay, invasion/migration assays, western blot for pathway phosphorylation\",\n      \"journal\": \"OncoTargets and therapy\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single method (western blot for pathway activation) with no binding or rescue experiment, single lab\",\n      \"pmids\": [\"30319275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Knockdown of CLDN6 in HepG2 hepatocellular carcinoma cells inhibits proliferation, migration, and invasion and reduces activation of the EGFR/AKT/mTOR signaling pathway; EGFR inhibitor AG1478 suppresses the pro-proliferative effects of CLDN6 overexpression.\",\n      \"method\": \"siRNA knockdown, overexpression, western blot for pathway activation, pharmacological inhibition (AG1478), in vitro functional assays\",\n      \"journal\": \"Cell biochemistry and function\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — western blot pathway inference plus pharmacological rescue, no direct binding shown, single lab\",\n      \"pmids\": [\"32056244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CLDN6 knockdown in hepatocellular carcinoma cells decreases phosphorylation of JAK2 and STAT3, reduces anti-apoptotic Bcl-2, and increases cleaved caspase-3 and Bax, placing CLDN6 upstream of the JAK2/STAT3 anti-apoptotic pathway in HCC.\",\n      \"method\": \"siRNA knockdown, overexpression, western blot for pathway phosphorylation, apoptosis assays (flow cytometry), transwell assay\",\n      \"journal\": \"Translational cancer research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — western blot pathway inference only, no direct binding or rescue experiments, single lab\",\n      \"pmids\": [\"37588735\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"CLDN6 gene expression in esophageal squamous cell carcinoma cell lines is silenced by DNA methylation of its promoter; treatment with the demethylating agent 5-aza-2'-deoxycytidine reduces methylation and restores CLDN6 mRNA expression.\",\n      \"method\": \"Methylation analysis, 5-aza-2'-deoxycytidine demethylation treatment, quantitative RT-PCR\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct demethylation-restoration experiment linking methylation to silencing, replicated across multiple cell lines\",\n      \"pmids\": [\"19288010\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CLDN6 sequesters PDLIM2 at the cell membrane, reducing nuclear PDLIM2-mediated RelA (NF-κB) ubiquitination; accumulated RelA transcriptionally upregulates METTL14, which enhances m6A modification and degradation of SOX4 mRNA, attenuating PI3K/Akt signaling and triggering autophagic cell death in breast cancer.\",\n      \"method\": \"Co-immunoprecipitation, nuclear fractionation, western blot, m6A modification assay, ChIP, luciferase reporter, in vitro and in vivo functional assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus multiple orthogonal methods establishing mechanistic pathway, single lab\",\n      \"pmids\": [\"42070760\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CLDN6 was identified as a defining surface marker of columnar trophoblast (bridging villous and extravillous compartments) during human chorion development; prospective isolation of CLDN6+ cells revealed their capacity to reacquire a proliferative villous state and, under directed cues, generate both syncytial and extravillous fates.\",\n      \"method\": \"Single-cell transcriptomics, spatial transcriptomics, prospective cell isolation using CLDN6 as surface marker, directed differentiation assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — CLDN6 used as marker for cell isolation, functional potential assessed in directed culture, preprint not peer-reviewed, single study\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"CLDN6 is a tetraspan tight junction protein whose C-terminal cytoplasmic tail (containing a PDZ-binding motif) is required for correct membrane targeting; through this motif it forms complexes with multiple scaffold and signaling proteins—including LATS1/2 (suppressing Hippo/YAP1 signaling), AF-6/afadin (suppressing ERK), ZO-1/PTEN (stabilizing p53 via AKT/MDM2), MAGI2 (blocking KLF5/SREBP1-driven RAS palmitoylation), LKB1 (activating AMPK/ULK1-dependent autophagy), RIP1 (activating ASK1/JNK to suppress glycolysis), DLG1/PBK (promoting ferroptosis via NRF2), TAZ (suppressing c-MYC-driven glycolysis), and SRC-family kinases BLK and SRC (mediating epithelial differentiation)—and its promoter is silenced by DNMT1-mediated DNA methylation downstream of TGFβ/SMAD2 signaling, with its expression producing context-dependent tumor-suppressive or oncogenic outcomes depending on the cancer type.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CLDN6 is a tetraspan tight junction membrane protein that functions as a context-dependent signaling hub, coupling its C-terminal cytoplasmic tail to scaffold and kinase partners to control proliferation, differentiation, metabolism, and cell death—most extensively characterized in breast cancer but also acting in gastric, hepatocellular, colorectal, and lung tumors [#13, #16, #0]. Correct membrane targeting of CLDN6 depends on its cytoplasmic tail, whose deletion mislocalizes CLDN6 and partner claudins and disrupts epidermal and hair-follicle differentiation in vivo [#7, #8]. Many of its signaling functions are routed through a C-terminal PDZ-binding motif that docks scaffold proteins: CLDN6 binds ZO-1 to assemble a PTEN-containing complex that stabilizes p53 by restraining AKT/MDM2-mediated ubiquitination [#14], binds MAGI2 to block KLF5/SREBF1-driven palmitate synthesis and thereby impair oncogenic RAS palmitoylation and membrane localization [#13], and binds LKB1 to activate AMPK/ULK1-dependent autophagy [#18]. CLDN6 also engages SRC-family kinases BLK and SRC directly through its C-terminal domain in a phosphotyrosine-independent manner, and these kinases are required for CLDN6-triggered epithelial differentiation [#16]. A recurring tumor-suppressive theme is restraint of growth-promoting kinase cascades and reprogramming of metabolism: CLDN6 suppresses ERK signaling via AF-6/afadin and the ERK/Sp1/cyclin D1 and ERK/IL-8 axes [#5, #11], activates ASK1- and RIP1/JNK-dependent pathways to drive apoptosis and suppress aerobic glycolysis [#3, #17], and lowers TAZ to dampen c-MYC-driven glycolysis [#10]. CLDN6 expression is silenced by promoter DNA methylation across esophageal, lung, and other carcinomas, with TGFβ/SMAD2 signaling driving DNMT1 recruitment to the CLDN6 promoter [#22, #9, #17]. Its activity is not uniformly suppressive: by interacting with LATS1/2 or a TJP2 complex, CLDN6 can promote YAP1 nuclear entry to drive EMT and lineage shifts, producing oncogenic outcomes in gastric and hepatocellular carcinoma [#0, #1].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Established that the CLDN6 cytoplasmic tail is required for correct membrane targeting and that CLDN6 dosage and localization control epidermal differentiation, defining its first in vivo physiological role.\",\n      \"evidence\": \"Tail-truncation and overexpression transgenic mouse models with histology, immunofluorescence, and differentiation-marker western blots\",\n      \"pmids\": [\"16847338\", \"15908185\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define the molecular partners bound by the tail in epidermis\", \"Mechanism linking mislocalization to the unfolding-protein response not resolved\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showed that loss of CLDN6 in carcinoma is driven by promoter DNA methylation, establishing an epigenetic silencing mechanism for its downregulation.\",\n      \"evidence\": \"Promoter methylation analysis and 5-aza-2'-deoxycytidine demethylation-restoration in esophageal squamous carcinoma cell lines\",\n      \"pmids\": [\"19288010\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not identify the upstream signal directing methylation\", \"Functional consequence of restored CLDN6 not tested here\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Connected an upstream signaling input to CLDN6 silencing by showing TGFβ/SMAD2 drives DNMT1 binding and methylation of the CLDN6 promoter, placing CLDN6 loss within EMT programs.\",\n      \"evidence\": \"ChIP for DNMT1 promoter occupancy, SB431542 inhibition, and CLDN6 siRNA rescue in cancer cells\",\n      \"pmids\": [\"28867761\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not establish which cancer contexts depend on this axis\", \"SMAD2-independent silencing routes not excluded\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated that CLDN6 physically engages signaling and scaffold partners (p53, AF-6) to control chemoresistance and ERK signaling, opening the model of CLDN6 as a membrane-anchored signaling regulator rather than a passive junction protein.\",\n      \"evidence\": \"Co-IP, co-localization, RNAi/overexpression, and pharmacological rescue (PMA) in breast cancer cells\",\n      \"pmids\": [\"29116019\", \"29159771\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct versus indirect nature of the p53 interaction not structurally resolved\", \"Whether the PDZ motif mediates these interactions not tested in these studies\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Placed CLDN6 upstream of an ASK1-p38/JNK apoptotic cascade, linking CLDN6 restoration to stress-kinase-driven cell death.\",\n      \"evidence\": \"Stable transfection, ASK1 pharmacological inhibition (TRX1), TUNEL, and apoptosis-marker western blots in MCF-7 cells\",\n      \"pmids\": [\"27035750\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct CLDN6-ASK1 binding shown\", \"Mechanism reducing ASK1 Ser967 phosphorylation unresolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Revealed opposing roles for CLDN6 in Hippo signaling—suppressing LATS1/2 to promote oncogenic YAP1/EMT in gastric cancer versus inducing autophagy downstream of ERβ in breast cancer—establishing its context-dependent output.\",\n      \"evidence\": \"Co-IP and phosphorylation assays for LATS1/2-YAP1; ChIP, luciferase, beclin1-knockdown rescue, and xenografts for ERβ/CLDN6/autophagy\",\n      \"pmids\": [\"31827075\", \"31412908\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"What determines tumor-suppressive versus oncogenic Hippo output not defined\", \"Direct LATS1/2 binding interface not mapped\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended CLDN6's regulatory reach to hypoxia and Wnt signaling by showing it sequesters β-catenin to drive HIF-1α degradation through a SENP1-dependent feedback loop.\",\n      \"evidence\": \"RNAi, ChIP, mRNA sequencing, and metastasis assays with clinical samples in breast cancer\",\n      \"pmids\": [\"32093760\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct CLDN6-β-catenin binding interface not defined\", \"Generality beyond breast cancer untested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined CLDN6 as a metabolic regulator by showing TJP2-dependent YAP1 activation and TAZ-dependent c-MYC suppression of glycolysis, linking junctional partners to tumor energy metabolism and lineage.\",\n      \"evidence\": \"Co-IP, metabolomic lactate/glucose measurements, and functional assays in hepatocellular and breast cancer cells\",\n      \"pmids\": [\"33536280\", \"35008557\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How CLDN6 chooses between TAZ suppression and TJP2/YAP1 activation unresolved\", \"TAZ degradation mechanism not defined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Anchored CLDN6 signaling to its PDZ-binding motif and SRC-family kinases, showing direct, phosphotyrosine-independent binding of BLK and SRC required for differentiation and PDZ-motif-dependent assembly of ZO-1/PTEN and JNK/c-Jun complexes.\",\n      \"evidence\": \"Recombinant-protein pull-downs and double-knockout F9 cells for BLK/SRC; Co-IP, ChIP, luciferase, and in vivo metastasis models for ZO-1/PTEN and JNK/c-Jun\",\n      \"pmids\": [\"37443730\", \"37852424\", \"36935496\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of PDZ-partner selectivity not determined\", \"Whether SRC-family binding and PDZ-scaffold binding are mutually exclusive unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Expanded the CLDN6 scaffold network to metabolic and stress-kinase control, with MAGI2 binding restraining SREBF1/RAS palmitoylation and RIP1 binding activating ASK1/JNK to suppress glycolysis in lung cancer.\",\n      \"evidence\": \"Co-IP, IP-ABE acyl-biotin exchange, ChIP, and xenografts (breast); Co-IP, methylation-specific PCR, and Seahorse assays (NSCLC)\",\n      \"pmids\": [\"39169280\", \"38462752\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"RIP1 interaction shown by Co-IP without direct binding validation\", \"Cross-talk between these parallel CLDN6 outputs unmapped\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established CLDN6 as a controller of autophagy and ferroptosis through LKB1/AMPK/ULK1 and DLG1/PBK/NRF2 axes, showing both protective (chemoresistance) and lethal (ferroptosis) outcomes depending on partner engagement.\",\n      \"evidence\": \"Co-IP, autophagy and ferroptosis assays, UPS-inhibition rescue, and in vivo models in breast cancer\",\n      \"pmids\": [\"40959289\", \"39984471\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"What dictates protective versus lethal autophagy outcome unresolved\", \"PBK recruitment via the endosomal pathway mechanistically incomplete\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved what molecular switch determines whether CLDN6 acts as a tumor suppressor or oncogene across tissues, and whether a unifying biochemical rule governs PDZ-partner selection and the divergent downstream outcomes.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of CLDN6 PDZ-motif/partner complexes\", \"Context-determining factors for opposing Hippo, autophagy, and metabolic outputs unknown\", \"Native tight-junction barrier function relative to signaling role not directly compared\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [13, 14, 16, 18]},\n      {\"term_id\": \"GO:0140313\", \"supporting_discovery_ids\": [6, 4, 15, 23]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [7, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [7, 15, 23]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [4, 6]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 5, 11, 14]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [2, 12, 18, 23]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3, 15, 23]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [10, 13, 17]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [7, 8, 16]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"LATS1\", \"TJP2\", \"AF-6\", \"MAGI2\", \"LKB1\", \"RIP1\", \"TAZ\", \"SRC\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}