{"gene":"PKP3","run_date":"2026-06-10T06:43:35","timeline":{"discoveries":[{"year":2021,"finding":"PKP3 protein levels are stabilized in response to canonical Wnt pathway activation (Wnt ligand or dominant-active LRP6 receptor), and conversely reduced by destruction-complex components GSK3β and Axin. PKP3 physically associates with GSK3β and Axin. Upon Wnt ligand stimulation, PKP3 trans-localizes into the nucleus and stimulates a Wnt transcriptional reporter.","method":"Co-immunoprecipitation (association with GSK3β and Axin), dominant-active LRP6 and Wnt-ligand stimulation assays for protein level changes, nuclear localization imaging, luciferase Wnt reporter assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal co-IP and multiple functional readouts (protein stability, localization, reporter assay) in a single lab study","pmids":["34058472"],"is_preprint":false},{"year":2018,"finding":"PKP3 activates the MAPK-JNK-ERK1/2-mTOR pathway to regulate autophagy and invasion in ovarian cancer cells; silencing PKP3 decreases proliferation and invasion, while PKP3 overexpression increases them through mTOR-mediated autophagy regulation.","method":"siRNA-mediated PKP3 knockdown and PKP3 overexpression in SKOV3/A2780 cells; Western blotting for MAPK/mTOR pathway components; invasion and proliferation assays","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, indirect pathway inference from knockdown/overexpression without direct biochemical reconstitution of PKP3-MAPK interaction","pmids":["30527804"],"is_preprint":false},{"year":2024,"finding":"FERMT1 upregulates PKP3 expression, which in turn activates the p38 MAPK signaling pathway to promote migration and invasion in non-small cell lung cancer; PKP3 knockdown counteracts the p38 MAPK activation induced by FERMT1 overexpression.","method":"Western blotting for p38 MAPK pathway components; Transwell migration/invasion assays; siRNA knockdown of PKP3; FERMT1 overexpression","journal":"BMC cancer","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, epistasis inferred from KD/OE experiments without direct biochemical interaction between FERMT1, PKP3, and p38 MAPK","pmids":["38200443"],"is_preprint":false},{"year":2025,"finding":"PKP3 is a direct target of miR-10b-5p (confirmed by dual luciferase reporter assay); miR-10b-5p downregulates PKP3, which in turn suppresses the RIPK3/MLKL necroptosis signaling pathway, thereby increasing cell proliferation and decreasing necroptosis in lung adenocarcinoma.","method":"Dual luciferase reporter assay for miR-10b-5p targeting of PKP3 3'UTR; Western blot for RIPK3/MLKL pathway; PKP3 knockdown rescue experiments; in vivo xenograft mouse model","journal":"Oncology reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct target validated by luciferase reporter, pathway placement confirmed by knockdown rescue and in vivo model, single lab","pmids":["40116080"],"is_preprint":false},{"year":2023,"finding":"PKP3 augments ERCC1 expression by activating the MAPK pathway in ovarian granulosa cells; CFDTW treatment reduces PKP3 expression by enhancing methylation of the PKP3 promoter, thereby modulating granulosa cell proliferation and apoptosis through the PKP3/MAPK/ERCC1 axis.","method":"PKP3/ERCC1 overexpression and knockdown in ovarian granulosa cells; Western blotting for MAPK components; methylation analysis of PKP3 promoter; cell proliferation and apoptosis assays","journal":"Journal of ovarian research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pathway placement based on OE/KD without direct biochemical reconstitution; promoter methylation assessed indirectly","pmids":["37420272"],"is_preprint":false},{"year":2021,"finding":"A sequence in the gene body of PKP3 exhibits methylation-dependent promoter activity in lung epithelial cells, as demonstrated by luciferase reporter assays in the presence and absence of methylation.","method":"Luciferase reporter assay with methylated and unmethylated PKP3 gene-body sequence in lung epithelial cells","journal":"Epigenetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct functional reporter assay with methylation manipulation; single lab but clear mechanistic readout","pmids":["34415821"],"is_preprint":false},{"year":2018,"finding":"DNP (N,N'-dinitrosopiperazine) decreases PKP3 expression in nasopharyngeal carcinoma cells through upregulation of miR-149, which targets PKP3; this decrease in PKP3 contributes to increased NPC cell proliferation, adhesion, migration, and invasion.","method":"miR-149 inhibitor rescue experiments; miR-149 overexpression; Western blotting for PKP3; cell migration/invasion assays","journal":"Molecular carcinogenesis","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, indirect evidence that miR-149 targets PKP3 without direct 3'UTR validation reported in abstract","pmids":["30144176"],"is_preprint":false}],"current_model":"PKP3 is a desmosomal plakophilin-subfamily catenin that participates in canonical Wnt signaling (associating with GSK3β and Axin, stabilized by Wnt ligands, and translocating to the nucleus to activate Wnt-responsive transcription), acts upstream of MAPK/p38/ERK/mTOR pathways to regulate cell proliferation, invasion, and autophagy, and promotes necroptosis in lung cells by sustaining RIPK3/MLKL pathway activity; its expression is post-transcriptionally regulated by miRNAs (miR-149, miR-10b-5p) and epigenetically regulated through promoter methylation."},"narrative":{"mechanistic_narrative":"PKP3 is a plakophilin-subfamily catenin that functions as a signaling adaptor coupling membrane and cytoplasmic signaling to transcriptional and cell-fate outcomes. It participates in canonical Wnt signaling: PKP3 protein is stabilized by Wnt-ligand or dominant-active LRP6 stimulation and destabilized by the destruction-complex components GSK3β and Axin, with which it physically associates; upon Wnt stimulation it translocates to the nucleus and activates a Wnt transcriptional reporter [PMID:34058472]. PKP3 also influences cell proliferation and survival through its post-transcriptional regulation, as it is a direct target of miR-10b-5p and acts to sustain RIPK3/MLKL necroptosis signaling, such that loss of PKP3 promotes proliferation and reduces necroptosis in lung adenocarcinoma [PMID:40116080]. PKP3 expression is further controlled epigenetically through a methylation-dependent regulatory sequence in its gene body that drives promoter activity in lung epithelial cells [PMID:34415821]. Beyond these axes, direct biochemical mechanisms linking PKP3 to downstream effectors remain incompletely characterized in the available corpus.","teleology":[{"year":2018,"claim":"Established that PKP3 levels are subject to microRNA control, framing it as a regulated node rather than a static structural protein, with functional consequences for tumor cell behavior.","evidence":"miR-149 overexpression/inhibitor rescue and Western blot for PKP3 in nasopharyngeal carcinoma cells","pmids":["30144176"],"confidence":"Low","gaps":["No direct 3'UTR luciferase validation of miR-149 targeting reported","Single lab, single cancer model","Mechanism linking PKP3 loss to migration/invasion not biochemically defined"]},{"year":2018,"claim":"Addressed how PKP3 influences cell proliferation and invasion, placing it upstream of MAPK-JNK-ERK1/2-mTOR signaling and autophagy.","evidence":"siRNA knockdown and overexpression in ovarian cancer cells with Western blot of pathway components and invasion/proliferation assays","pmids":["30527804"],"confidence":"Low","gaps":["Pathway placement inferred from KD/OE, not direct PKP3-MAPK biochemical interaction","No reconstitution of the proposed signaling chain","Single lab"]},{"year":2021,"claim":"Defined a direct link between PKP3 and canonical Wnt signaling, showing PKP3 is a destruction-complex-regulated factor that enters the nucleus to drive Wnt-responsive transcription.","evidence":"Co-IP with GSK3β and Axin, Wnt-ligand/dominant-active LRP6 stability assays, nuclear localization imaging, and Wnt luciferase reporter","pmids":["34058472"],"confidence":"Medium","gaps":["Direct nuclear transcriptional targets of PKP3 not identified","Single lab","Stoichiometry and structural basis of GSK3β/Axin association unknown"]},{"year":2021,"claim":"Showed that PKP3 expression is itself epigenetically controlled, identifying a methylation-dependent regulatory sequence in its gene body active in lung epithelial cells.","evidence":"Luciferase reporter assays comparing methylated and unmethylated PKP3 gene-body sequence","pmids":["34415821"],"confidence":"Medium","gaps":["Endogenous methylation status across tissues not mapped","Transcription factors acting at this element not identified"]},{"year":2023,"claim":"Extended the PKP3/MAPK axis to a downstream effector, linking PKP3 to ERCC1 expression and to promoter-methylation-based regulation in ovarian granulosa cells.","evidence":"OE/KD of PKP3 and ERCC1 with Western blot for MAPK, promoter methylation analysis, proliferation/apoptosis assays","pmids":["37420272"],"confidence":"Low","gaps":["No direct biochemical reconstitution of the PKP3/MAPK/ERCC1 axis","Promoter methylation assessed indirectly","Single lab"]},{"year":2024,"claim":"Positioned PKP3 within an upstream regulatory cascade, showing FERMT1 acts through PKP3 to activate p38 MAPK and drive lung cancer migration/invasion.","evidence":"FERMT1 overexpression with PKP3 knockdown epistasis, Western blot for p38 MAPK, Transwell assays in NSCLC","pmids":["38200443"],"confidence":"Low","gaps":["No direct FERMT1-PKP3 or PKP3-p38 physical interaction shown","Epistasis inferred from KD/OE only","Single lab"]},{"year":2025,"claim":"Resolved a direct post-transcriptional regulator and a cell-death output, validating PKP3 as a miR-10b-5p target that sustains RIPK3/MLKL necroptosis signaling.","evidence":"Dual luciferase 3'UTR reporter, RIPK3/MLKL Western blot, knockdown rescue, and xenograft model in lung adenocarcinoma","pmids":["40116080"],"confidence":"Medium","gaps":["Mechanism by which PKP3 sustains RIPK3/MLKL activity not defined","Direct physical interaction with necroptosis machinery not shown","Single lab"]},{"year":null,"claim":"How PKP3's desmosomal/structural role integrates with its signaling functions in Wnt, MAPK, and necroptosis, and what its direct transcriptional or effector partners are, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct PKP3 transcriptional targets identified","No structural model of signaling complexes","Integration of multiple pathway roles not reconciled in one system"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3]}],"complexes":[],"partners":["GSK3B","AXIN1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9Y446","full_name":"Plakophilin-3","aliases":[],"length_aa":797,"mass_kda":87.1,"function":"A component of desmosome cell-cell junctions which are required for positive regulation of cellular adhesion (PubMed:24124604). Required for the localization of DSG2, DSP and PKP2 to mature desmosome junctions (PubMed:20859650). May also play a role in the maintenance of DSG3 protein abundance in keratinocytes (By similarity). Required for the formation of DSP-containing desmosome precursors in the cytoplasm during desmosome assembly (PubMed:25208567). Also regulates the accumulation of CDH1 to mature desmosome junctions, via cAMP-dependent signaling and its interaction with activated RAP1A (PubMed:25208567). Positively regulates the stabilization of PKP2 mRNA and therefore protein abundance, via its interaction with FXR1, may also regulate the protein abundance of DSP via the same mechanism (PubMed:25225333). May also regulate the protein abundance of the desmosome component PKP1 (By similarity). Required for the organization of desmosome junctions at intercellular borders between basal keratinocytes of the epidermis, as a result plays a role in maintenance of the dermal barrier and regulation of the dermal inflammatory response (By similarity). Required during epidermal keratinocyte differentiation for cell adherence at tricellular cell-cell contacts, via regulation of the timely formation of adherens junctions and desmosomes in a calcium-dependent manner, and may also play a role in the organization of the intracellular actin fiber belt (By similarity). Acts as a negative regulator of the inflammatory response in hematopoietic cells of the skin and intestine, via modulation of proinflammatory cytokine production (By similarity). Important for epithelial barrier maintenance in the intestine to reduce intestinal permeability, thereby plays a role in protection from intestinal-derived endotoxemia (By similarity). Required for the development of hair follicles, via a role in the regulation of inner root sheaf length, correct alignment and anterior-posterior polarity of hair follicles (By similarity). Promotes proliferation and cell-cycle G1/S phase transition of keratinocytes (By similarity). Promotes E2F1-driven transcription of G1/S phase promoting genes by acting to release E2F1 from its inhibitory interaction with RB1, via sequestering RB1 and CDKN1A to the cytoplasm and thereby increasing CDK4- and CDK6-driven phosphorylation of RB1 (By similarity). May act as a scaffold protein to facilitate MAPK phosphorylation of RPS6KA protein family members and subsequently promote downstream EGFR signaling (By similarity). May play a role in the positive regulation of transcription of Wnt-mediated TCF-responsive target genes (PubMed:34058472)","subcellular_location":"Cell junction, desmosome; Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q9Y446/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PKP3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PKP3","total_profiled":1310},"omim":[{"mim_id":"605561","title":"PLAKOPHILIN 3; PKP3","url":"https://www.omim.org/entry/605561"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Cell Junctions","reliability":"Enhanced"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"esophagus","ntpm":283.5},{"tissue":"skin 1","ntpm":212.8}],"url":"https://www.proteinatlas.org/search/PKP3"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9Y446","domains":[{"cath_id":"1.25.10.10","chopping":"308-433","consensus_level":"medium","plddt":92.2849,"start":308,"end":433},{"cath_id":"1.25.10.10","chopping":"470-553_586-688","consensus_level":"medium","plddt":92.7923,"start":470,"end":688},{"cath_id":"1.20.1050","chopping":"703-797","consensus_level":"medium","plddt":92.2647,"start":703,"end":797}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y446","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y446-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y446-F1-predicted_aligned_error_v6.png","plddt_mean":68.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PKP3","jax_strain_url":"https://www.jax.org/strain/search?query=PKP3"},"sequence":{"accession":"Q9Y446","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y446.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y446/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y446"}},"corpus_meta":[{"pmid":"12827610","id":"PMC_12827610","title":"Immunohistochemical localization of plakophilins (PKP1, PKP2, PKP3, and p0071) in primary oropharyngeal tumors: correlation with clinical parameters.","date":"2003","source":"Human pathology","url":"https://pubmed.ncbi.nlm.nih.gov/12827610","citation_count":62,"is_preprint":false},{"pmid":"22223854","id":"PMC_22223854","title":"Common polymorphisms in the PKP3-SIGIRR-TMEM16J gene region are associated with susceptibility to tuberculosis.","date":"2012","source":"The Journal of infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/22223854","citation_count":48,"is_preprint":false},{"pmid":"21194493","id":"PMC_21194493","title":"Expression of plakophilins (PKP1, PKP2, and PKP3) in gastric cancers.","date":"2011","source":"Diagnostic pathology","url":"https://pubmed.ncbi.nlm.nih.gov/21194493","citation_count":41,"is_preprint":false},{"pmid":"21947748","id":"PMC_21947748","title":"Expression of Plakophilins (PKP1, PKP2, and PKP3) in breast cancers.","date":"2011","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/21947748","citation_count":34,"is_preprint":false},{"pmid":"30527804","id":"PMC_30527804","title":"PKP3 interactions with MAPK-JNK-ERK1/2-mTOR pathway regulates autophagy and invasion in ovarian cancer.","date":"2018","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/30527804","citation_count":32,"is_preprint":false},{"pmid":"28743649","id":"PMC_28743649","title":"First report of blaOXA-181-mediated carbapenem resistance in Aeromonas caviae in association with pKP3-A: Threat for rapid dissemination.","date":"2017","source":"Journal of global antimicrobial resistance","url":"https://pubmed.ncbi.nlm.nih.gov/28743649","citation_count":25,"is_preprint":false},{"pmid":"30144176","id":"PMC_30144176","title":"Dinitrosopiperazine-decreased PKP3 through upregulating miR-149 participates in nasopharyngeal carcinoma metastasis.","date":"2018","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/30144176","citation_count":16,"is_preprint":false},{"pmid":"26872154","id":"PMC_26872154","title":"Low Vitamin-D Levels Combined with PKP3-SIGIRR-TMEM16J Host Variants Is Associated with Tuberculosis and Death in HIV-Infected and -Exposed Infants.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26872154","citation_count":15,"is_preprint":false},{"pmid":"34058472","id":"PMC_34058472","title":"A catenin of the plakophilin-subfamily, Pkp3, responds to canonical-Wnt pathway components and signals.","date":"2021","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/34058472","citation_count":13,"is_preprint":false},{"pmid":"37420272","id":"PMC_37420272","title":"Cangfu Daotan Wan alleviates polycystic ovary syndrome with phlegm-dampness syndrome via disruption of the PKP3/ERCC1/MAPK axis.","date":"2023","source":"Journal of ovarian research","url":"https://pubmed.ncbi.nlm.nih.gov/37420272","citation_count":12,"is_preprint":false},{"pmid":"38200443","id":"PMC_38200443","title":"FERMT1 promotes cell migration and invasion in non-small cell lung cancer via regulating PKP3-mediated activation of p38 MAPK signaling.","date":"2024","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38200443","citation_count":10,"is_preprint":false},{"pmid":"34733461","id":"PMC_34733461","title":"Analysis of Multiple Human Tumor Cases Reveals the Carcinogenic Effects of PKP3.","date":"2021","source":"Journal of healthcare engineering","url":"https://pubmed.ncbi.nlm.nih.gov/34733461","citation_count":6,"is_preprint":false},{"pmid":"40612005","id":"PMC_40612005","title":"KRT6A, KRT6B, PKP1, and PKP3 as key hub genes in esophageal cancer: A combined bioinformatics and experimental study.","date":"2025","source":"Biochemistry and biophysics reports","url":"https://pubmed.ncbi.nlm.nih.gov/40612005","citation_count":4,"is_preprint":false},{"pmid":"34415821","id":"PMC_34415821","title":"Disease-related blood-based differential methylation in cystic fibrosis and its representation in lung cancer revealed a regulatory locus in PKP3 in lung epithelial cells.","date":"2021","source":"Epigenetics","url":"https://pubmed.ncbi.nlm.nih.gov/34415821","citation_count":3,"is_preprint":false},{"pmid":"40116080","id":"PMC_40116080","title":"Induction of necroptosis in lung adenocarcinoma by miR‑10b‑5p through modulation of the PKP3/RIPK3/MLKL cascade.","date":"2025","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/40116080","citation_count":2,"is_preprint":false},{"pmid":"41351372","id":"PMC_41351372","title":"CircFOXK2 induces non-small cell lung cancer tumorigenesis through the miR-328-5p/PKP3 axis.","date":"2025","source":"Cellular and molecular biology (Noisy-le-Grand, France)","url":"https://pubmed.ncbi.nlm.nih.gov/41351372","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10695,"output_tokens":1856,"usd":0.029962,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8742,"output_tokens":2537,"usd":0.053567,"stage2_stop_reason":"end_turn"},"total_usd":0.083529,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"PKP3 protein levels are stabilized in response to canonical Wnt pathway activation (Wnt ligand or dominant-active LRP6 receptor), and conversely reduced by destruction-complex components GSK3β and Axin. PKP3 physically associates with GSK3β and Axin. Upon Wnt ligand stimulation, PKP3 trans-localizes into the nucleus and stimulates a Wnt transcriptional reporter.\",\n      \"method\": \"Co-immunoprecipitation (association with GSK3β and Axin), dominant-active LRP6 and Wnt-ligand stimulation assays for protein level changes, nuclear localization imaging, luciferase Wnt reporter assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal co-IP and multiple functional readouts (protein stability, localization, reporter assay) in a single lab study\",\n      \"pmids\": [\"34058472\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PKP3 activates the MAPK-JNK-ERK1/2-mTOR pathway to regulate autophagy and invasion in ovarian cancer cells; silencing PKP3 decreases proliferation and invasion, while PKP3 overexpression increases them through mTOR-mediated autophagy regulation.\",\n      \"method\": \"siRNA-mediated PKP3 knockdown and PKP3 overexpression in SKOV3/A2780 cells; Western blotting for MAPK/mTOR pathway components; invasion and proliferation assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, indirect pathway inference from knockdown/overexpression without direct biochemical reconstitution of PKP3-MAPK interaction\",\n      \"pmids\": [\"30527804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"FERMT1 upregulates PKP3 expression, which in turn activates the p38 MAPK signaling pathway to promote migration and invasion in non-small cell lung cancer; PKP3 knockdown counteracts the p38 MAPK activation induced by FERMT1 overexpression.\",\n      \"method\": \"Western blotting for p38 MAPK pathway components; Transwell migration/invasion assays; siRNA knockdown of PKP3; FERMT1 overexpression\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, epistasis inferred from KD/OE experiments without direct biochemical interaction between FERMT1, PKP3, and p38 MAPK\",\n      \"pmids\": [\"38200443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PKP3 is a direct target of miR-10b-5p (confirmed by dual luciferase reporter assay); miR-10b-5p downregulates PKP3, which in turn suppresses the RIPK3/MLKL necroptosis signaling pathway, thereby increasing cell proliferation and decreasing necroptosis in lung adenocarcinoma.\",\n      \"method\": \"Dual luciferase reporter assay for miR-10b-5p targeting of PKP3 3'UTR; Western blot for RIPK3/MLKL pathway; PKP3 knockdown rescue experiments; in vivo xenograft mouse model\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct target validated by luciferase reporter, pathway placement confirmed by knockdown rescue and in vivo model, single lab\",\n      \"pmids\": [\"40116080\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PKP3 augments ERCC1 expression by activating the MAPK pathway in ovarian granulosa cells; CFDTW treatment reduces PKP3 expression by enhancing methylation of the PKP3 promoter, thereby modulating granulosa cell proliferation and apoptosis through the PKP3/MAPK/ERCC1 axis.\",\n      \"method\": \"PKP3/ERCC1 overexpression and knockdown in ovarian granulosa cells; Western blotting for MAPK components; methylation analysis of PKP3 promoter; cell proliferation and apoptosis assays\",\n      \"journal\": \"Journal of ovarian research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pathway placement based on OE/KD without direct biochemical reconstitution; promoter methylation assessed indirectly\",\n      \"pmids\": [\"37420272\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A sequence in the gene body of PKP3 exhibits methylation-dependent promoter activity in lung epithelial cells, as demonstrated by luciferase reporter assays in the presence and absence of methylation.\",\n      \"method\": \"Luciferase reporter assay with methylated and unmethylated PKP3 gene-body sequence in lung epithelial cells\",\n      \"journal\": \"Epigenetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct functional reporter assay with methylation manipulation; single lab but clear mechanistic readout\",\n      \"pmids\": [\"34415821\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"DNP (N,N'-dinitrosopiperazine) decreases PKP3 expression in nasopharyngeal carcinoma cells through upregulation of miR-149, which targets PKP3; this decrease in PKP3 contributes to increased NPC cell proliferation, adhesion, migration, and invasion.\",\n      \"method\": \"miR-149 inhibitor rescue experiments; miR-149 overexpression; Western blotting for PKP3; cell migration/invasion assays\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, indirect evidence that miR-149 targets PKP3 without direct 3'UTR validation reported in abstract\",\n      \"pmids\": [\"30144176\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PKP3 is a desmosomal plakophilin-subfamily catenin that participates in canonical Wnt signaling (associating with GSK3β and Axin, stabilized by Wnt ligands, and translocating to the nucleus to activate Wnt-responsive transcription), acts upstream of MAPK/p38/ERK/mTOR pathways to regulate cell proliferation, invasion, and autophagy, and promotes necroptosis in lung cells by sustaining RIPK3/MLKL pathway activity; its expression is post-transcriptionally regulated by miRNAs (miR-149, miR-10b-5p) and epigenetically regulated through promoter methylation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PKP3 is a plakophilin-subfamily catenin that functions as a signaling adaptor coupling membrane and cytoplasmic signaling to transcriptional and cell-fate outcomes. It participates in canonical Wnt signaling: PKP3 protein is stabilized by Wnt-ligand or dominant-active LRP6 stimulation and destabilized by the destruction-complex components GSK3\\u03b2 and Axin, with which it physically associates; upon Wnt stimulation it translocates to the nucleus and activates a Wnt transcriptional reporter [#0]. PKP3 also influences cell proliferation and survival through its post-transcriptional regulation, as it is a direct target of miR-10b-5p and acts to sustain RIPK3/MLKL necroptosis signaling, such that loss of PKP3 promotes proliferation and reduces necroptosis in lung adenocarcinoma [#3]. PKP3 expression is further controlled epigenetically through a methylation-dependent regulatory sequence in its gene body that drives promoter activity in lung epithelial cells [#5]. Beyond these axes, direct biochemical mechanisms linking PKP3 to downstream effectors remain incompletely characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Established that PKP3 levels are subject to microRNA control, framing it as a regulated node rather than a static structural protein, with functional consequences for tumor cell behavior.\",\n      \"evidence\": \"miR-149 overexpression/inhibitor rescue and Western blot for PKP3 in nasopharyngeal carcinoma cells\",\n      \"pmids\": [\"30144176\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct 3'UTR luciferase validation of miR-149 targeting reported\", \"Single lab, single cancer model\", \"Mechanism linking PKP3 loss to migration/invasion not biochemically defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Addressed how PKP3 influences cell proliferation and invasion, placing it upstream of MAPK-JNK-ERK1/2-mTOR signaling and autophagy.\",\n      \"evidence\": \"siRNA knockdown and overexpression in ovarian cancer cells with Western blot of pathway components and invasion/proliferation assays\",\n      \"pmids\": [\"30527804\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Pathway placement inferred from KD/OE, not direct PKP3-MAPK biochemical interaction\", \"No reconstitution of the proposed signaling chain\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined a direct link between PKP3 and canonical Wnt signaling, showing PKP3 is a destruction-complex-regulated factor that enters the nucleus to drive Wnt-responsive transcription.\",\n      \"evidence\": \"Co-IP with GSK3\\u03b2 and Axin, Wnt-ligand/dominant-active LRP6 stability assays, nuclear localization imaging, and Wnt luciferase reporter\",\n      \"pmids\": [\"34058472\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct nuclear transcriptional targets of PKP3 not identified\", \"Single lab\", \"Stoichiometry and structural basis of GSK3\\u03b2/Axin association unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showed that PKP3 expression is itself epigenetically controlled, identifying a methylation-dependent regulatory sequence in its gene body active in lung epithelial cells.\",\n      \"evidence\": \"Luciferase reporter assays comparing methylated and unmethylated PKP3 gene-body sequence\",\n      \"pmids\": [\"34415821\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous methylation status across tissues not mapped\", \"Transcription factors acting at this element not identified\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended the PKP3/MAPK axis to a downstream effector, linking PKP3 to ERCC1 expression and to promoter-methylation-based regulation in ovarian granulosa cells.\",\n      \"evidence\": \"OE/KD of PKP3 and ERCC1 with Western blot for MAPK, promoter methylation analysis, proliferation/apoptosis assays\",\n      \"pmids\": [\"37420272\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct biochemical reconstitution of the PKP3/MAPK/ERCC1 axis\", \"Promoter methylation assessed indirectly\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Positioned PKP3 within an upstream regulatory cascade, showing FERMT1 acts through PKP3 to activate p38 MAPK and drive lung cancer migration/invasion.\",\n      \"evidence\": \"FERMT1 overexpression with PKP3 knockdown epistasis, Western blot for p38 MAPK, Transwell assays in NSCLC\",\n      \"pmids\": [\"38200443\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct FERMT1-PKP3 or PKP3-p38 physical interaction shown\", \"Epistasis inferred from KD/OE only\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved a direct post-transcriptional regulator and a cell-death output, validating PKP3 as a miR-10b-5p target that sustains RIPK3/MLKL necroptosis signaling.\",\n      \"evidence\": \"Dual luciferase 3'UTR reporter, RIPK3/MLKL Western blot, knockdown rescue, and xenograft model in lung adenocarcinoma\",\n      \"pmids\": [\"40116080\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which PKP3 sustains RIPK3/MLKL activity not defined\", \"Direct physical interaction with necroptosis machinery not shown\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PKP3's desmosomal/structural role integrates with its signaling functions in Wnt, MAPK, and necroptosis, and what its direct transcriptional or effector partners are, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct PKP3 transcriptional targets identified\", \"No structural model of signaling complexes\", \"Integration of multiple pathway roles not reconciled in one system\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"GSK3B\", \"AXIN1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":3,"faith_total":3,"faith_pct":100.0}}