{"gene":"PKP3","run_date":"2026-04-28T19:45:44","timeline":{"discoveries":[{"year":2021,"finding":"PKP3 protein levels are stabilized in response to canonical Wnt ligand or dominant-active LRP6 receptor, similar to beta-catenin and p120-catenin-isoform1; PKP3 associates with GSK3β and Axin (destruction complex components), and its levels are reduced upon overexpression of GSK3β or Axin; PKP3 trans-localizes into the nucleus in response to Wnt-ligand and its exogenous expression stimulates a Wnt reporter.","method":"Co-immunoprecipitation (PKP3 with GSK3β and Axin), luciferase Wnt reporter assay, nuclear localization imaging, overexpression and dominant-active receptor constructs","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2-3 — reciprocal association shown by co-IP, functional readout via Wnt reporter, nuclear localization imaging, but single lab study","pmids":["34058472"],"is_preprint":false},{"year":2018,"finding":"PKP3 activates the mTOR pathway via interaction with upstream MAPK pathway components to regulate autophagy and invasion in ovarian cancer; silencing PKP3 decreased proliferation, colony formation, and invasion, while overexpression upregulated these activities.","method":"siRNA knockdown, overexpression, pathway inhibitor assays, cell proliferation/invasion assays","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 — functional phenotype with pathway placement via western blot, single lab, no direct biochemical reconstitution of PKP3-MAPK interaction","pmids":["30527804"],"is_preprint":false},{"year":2018,"finding":"miR-149 directly decreases PKP3 expression; the carcinogen DNP upregulates miR-149 to suppress PKP3, thereby promoting NPC cell proliferation, adhesion, migration, and invasion; inhibition of miR-149 rescued PKP3 levels and blocked these pro-metastatic effects.","method":"miR-149 inhibitor rescue experiments, western blot, migration/invasion assays in NPC cell lines","journal":"Molecular carcinogenesis","confidence":"Low","confidence_rationale":"Tier 3 — functional rescue by miR-149 inhibitor implicates PKP3 as downstream target, but no direct validation of miR-149 binding site on PKP3 3'UTR reported","pmids":["30144176"],"is_preprint":false},{"year":2024,"finding":"FERMT1 upregulates PKP3 expression and activates the p38 MAPK signaling pathway; knockdown of PKP3 counteracts the p38 MAPK activation induced by FERMT1 overexpression, placing PKP3 downstream of FERMT1 and upstream of p38 MAPK in a migration/invasion-promoting axis in NSCLC.","method":"siRNA knockdown of PKP3, FERMT1 overexpression, western blot for p38 MAPK pathway components, Transwell migration/invasion assays","journal":"BMC cancer","confidence":"Low","confidence_rationale":"Tier 3 — genetic epistasis by knockdown/overexpression, single lab, no direct biochemical interaction between PKP3 and p38 MAPK shown","pmids":["38200443"],"is_preprint":false},{"year":2025,"finding":"miR-10b-5p directly targets the PKP3 3'UTR (validated by dual luciferase reporter assay) to suppress PKP3 expression; reduced PKP3 inhibits the RIPK3/MLKL necroptosis signaling pathway, promoting LUAD cell proliferation and suppressing necroptosis; PKP3 knockdown phenocopies miR-10b-5p overexpression and suppresses RIPK3/MLKL activation.","method":"Dual luciferase reporter assay, western blot (RIPK3/MLKL), siRNA knockdown of PKP3, miR-10b-5p overexpression/inhibition, xenograft mouse model","journal":"Oncology reports","confidence":"Medium","confidence_rationale":"Tier 2-3 — direct 3'UTR targeting validated by luciferase assay, pathway placement via multiple methods including in vivo model, single lab","pmids":["40116080"],"is_preprint":false},{"year":2025,"finding":"circFOXK2 acts as a sponge for miR-328-5p to upregulate PKP3, thereby promoting NSCLC cell proliferation, migration, and invasion; direct binding between miR-328-5p and circFOXK2 was validated by dual luciferase reporter assay.","method":"Dual luciferase reporter assay, qRT-PCR, CCK-8 proliferation assay, wound healing and Transwell invasion assays","journal":"Cellular and molecular biology","confidence":"Low","confidence_rationale":"Tier 3 — sponge mechanism validated for circFOXK2/miR-328-5p but PKP3 as direct target of miR-328-5p not independently validated by luciferase; single lab","pmids":["41351372"],"is_preprint":false},{"year":2021,"finding":"A sequence in the gene body of PKP3 exhibits methylation-dependent promoter activity in lung epithelial cells, demonstrated by luciferase reporter assays comparing methylated vs. unmethylated constructs; this region is hypermethylated in blood from cystic fibrosis patients with severe phenotype.","method":"Luciferase reporter assay with methylated and unmethylated PKP3 gene-body sequence in lung epithelial cells, bisulfite next-generation sequencing","journal":"Epigenetics","confidence":"Medium","confidence_rationale":"Tier 2 — direct functional demonstration of methylation-dependent promoter activity by luciferase assay, single lab but mechanistically rigorous","pmids":["34415821"],"is_preprint":false},{"year":2023,"finding":"PKP3 augments ERCC1 expression by activating the MAPK pathway; CFDTW treatment reduces PKP3 expression by enhancing methylation of the PKP3 promoter, which promotes proliferation and reduces apoptosis in ovarian granulosa cells through the PKP3/MAPK/ERCC1 axis.","method":"PKP3 overexpression/knockdown, ERCC1 expression analysis, MAPK pathway western blot, promoter methylation analysis, cell proliferation/apoptosis assays","journal":"Journal of ovarian research","confidence":"Low","confidence_rationale":"Tier 3 — pathway placement by overexpression/knockdown experiments, single lab, no direct biochemical demonstration of PKP3-MAPK interaction","pmids":["37420272"],"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 ligand, and translocating to the nucleus to stimulate Wnt target gene expression), activates downstream MAPK/p38 and mTOR pathways to promote cell proliferation and invasion, regulates necroptosis via the RIPK3/MLKL cascade, and is itself transcriptionally controlled by promoter methylation and post-transcriptionally suppressed by multiple miRNAs (miR-149, miR-10b-5p, miR-328-5p) acting through its 3'UTR."},"narrative":{"teleology":[{"year":2018,"claim":"Establishing that PKP3 is not merely a structural desmosomal protein but an upstream activator of mTOR signaling that promotes cancer cell proliferation, invasion, and autophagy regulation in ovarian cancer.","evidence":"siRNA knockdown and overexpression with pathway inhibitors and proliferation/invasion assays in ovarian cancer cells","pmids":["30527804"],"confidence":"Low","gaps":["No direct biochemical interaction between PKP3 and MAPK/mTOR components was demonstrated","Single cell-line context (ovarian cancer); generalizability unclear","Mechanism by which PKP3 engages MAPK pathway not resolved"]},{"year":2018,"claim":"Identifying PKP3 as a downstream target of miR-149 whose suppression by the carcinogen DNP promotes nasopharyngeal carcinoma cell migration and invasion, providing the first evidence for miRNA-mediated PKP3 regulation.","evidence":"miR-149 inhibitor rescue experiments and western blot in NPC cell lines treated with DNP","pmids":["30144176"],"confidence":"Low","gaps":["Direct binding of miR-149 to the PKP3 3′-UTR was not validated by luciferase reporter assay","Mechanism linking PKP3 loss to enhanced invasion not delineated"]},{"year":2021,"claim":"Revealing that PKP3 is a novel component of the canonical Wnt signaling cascade: it associates with the GSK3β/Axin destruction complex, is stabilized by Wnt ligand, translocates to the nucleus, and activates Wnt-responsive transcription—establishing PKP3 as a Wnt-responsive nuclear effector analogous to β-catenin.","evidence":"Co-immunoprecipitation of PKP3 with GSK3β and Axin, Wnt luciferase reporter assay, nuclear localization imaging upon Wnt stimulation or dominant-active LRP6","pmids":["34058472"],"confidence":"Medium","gaps":["Whether PKP3 directly binds TCF/LEF transcription factors in the nucleus is unknown","Not confirmed whether PKP3 is a direct phosphorylation substrate of GSK3β","Single lab study; independent replication lacking"]},{"year":2021,"claim":"Demonstrating that a gene-body sequence within PKP3 possesses methylation-dependent promoter activity in lung epithelial cells, linking epigenetic regulation to PKP3 transcriptional control.","evidence":"Luciferase reporter assays comparing methylated vs. unmethylated PKP3 gene-body constructs in lung epithelial cells; bisulfite sequencing in cystic fibrosis patient blood","pmids":["34415821"],"confidence":"Medium","gaps":["Whether gene-body methylation regulates endogenous PKP3 protein levels in vivo is not shown","Transcription factors responsive to the methylation state of this region are unidentified"]},{"year":2023,"claim":"Extending the PKP3–MAPK axis by showing PKP3 augments ERCC1 expression through MAPK activation in ovarian granulosa cells, and that PKP3 promoter methylation controls this signaling cascade.","evidence":"PKP3 overexpression/knockdown with ERCC1 and MAPK western blot, promoter methylation analysis in granulosa cells","pmids":["37420272"],"confidence":"Low","gaps":["No direct biochemical interaction between PKP3 and any MAPK component demonstrated","Single cell type; relevance to other tissues unclear"]},{"year":2024,"claim":"Placing PKP3 downstream of FERMT1 and upstream of p38 MAPK in an epistatic signaling axis that drives NSCLC migration and invasion, specifying p38 as the MAPK branch regulated by PKP3.","evidence":"siRNA knockdown of PKP3 reversing FERMT1-induced p38 MAPK activation; Transwell assays in NSCLC cells","pmids":["38200443"],"confidence":"Low","gaps":["Direct physical interaction between PKP3 and p38 MAPK or its upstream kinases not shown","Whether FERMT1 directly regulates PKP3 transcription or protein stability is unknown"]},{"year":2025,"claim":"Establishing PKP3 as a positive regulator of RIPK3/MLKL-dependent necroptosis and validating miR-10b-5p as a direct suppressor of PKP3 via its 3′-UTR, linking PKP3 loss to necroptosis evasion and tumor growth in LUAD.","evidence":"Dual luciferase reporter assay confirming miR-10b-5p targeting of PKP3 3′-UTR; PKP3 knockdown phenocopying miR-10b-5p overexpression; RIPK3/MLKL western blot; xenograft model","pmids":["40116080"],"confidence":"Medium","gaps":["Whether PKP3 directly binds RIPK3 or acts through an intermediary is unknown","Mechanism by which PKP3 activates the necroptosis cascade not resolved","Single cancer type studied (LUAD)"]},{"year":2025,"claim":"Identifying a circFOXK2/miR-328-5p/PKP3 regulatory axis that promotes NSCLC proliferation and invasion, adding another miRNA-mediated layer of PKP3 post-transcriptional control.","evidence":"Dual luciferase assay for circFOXK2–miR-328-5p interaction; qRT-PCR and functional assays in NSCLC cells","pmids":["41351372"],"confidence":"Low","gaps":["Direct targeting of PKP3 3′-UTR by miR-328-5p not independently validated by luciferase assay","Whether circFOXK2 regulation of PKP3 occurs in non-cancer contexts is unknown"]},{"year":null,"claim":"How PKP3 biochemically activates MAPK/p38 and RIPK3/MLKL pathways—whether through direct binding or adaptor-mediated mechanisms—remains unresolved, as does the structural basis for its interaction with the Wnt destruction complex and whether it acts as a transcriptional co-activator in the nucleus.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural or reconstituted biochemical data for PKP3 interaction with any signaling partner","Whether PKP3 desmosomal and signaling functions are mutually exclusive or coordinated is unknown","No in vivo genetic models (knockout mice) characterizing PKP3 physiological function"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,3,4]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,3,4]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[4]}],"complexes":[],"partners":["GSK3B","AXIN1","RIPK3","MLKL","FERMT1","ERCC1"],"other_free_text":[]},"mechanistic_narrative":"PKP3 is a plakophilin family member that functions beyond cell adhesion as a signaling intermediate linking Wnt, MAPK, and necroptosis pathways. PKP3 associates with the β-catenin destruction complex components GSK3β and Axin, is stabilized and translocates to the nucleus upon Wnt ligand stimulation, and activates Wnt-responsive transcription [PMID:34058472]. PKP3 also activates downstream MAPK/p38 and mTOR signaling to promote cell proliferation, invasion, and ERCC1 expression [PMID:30527804, PMID:38200443, PMID:37420272], and positively regulates RIPK3/MLKL-dependent necroptosis [PMID:40116080]. PKP3 expression is controlled by promoter/gene-body methylation [PMID:34415821] and is post-transcriptionally suppressed by miR-10b-5p, which directly targets its 3′-UTR [PMID:40116080], and by miR-149 [PMID:30144176]."},"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":40,"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":10,"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":9976,"output_tokens":2124,"usd":0.030894},"stage2":{"model":"claude-opus-4-6","input_tokens":5414,"output_tokens":2442,"usd":0.13218},"total_usd":0.163074,"stage1_batch_id":"msgbatch_01SUR8NDzVrNmyszWyJeCct7","stage2_batch_id":"msgbatch_01G7Yfutko3cDWzejrwH5AMx","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 ligand or dominant-active LRP6 receptor, similar to beta-catenin and p120-catenin-isoform1; PKP3 associates with GSK3β and Axin (destruction complex components), and its levels are reduced upon overexpression of GSK3β or Axin; PKP3 trans-localizes into the nucleus in response to Wnt-ligand and its exogenous expression stimulates a Wnt reporter.\",\n      \"method\": \"Co-immunoprecipitation (PKP3 with GSK3β and Axin), luciferase Wnt reporter assay, nuclear localization imaging, overexpression and dominant-active receptor constructs\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — reciprocal association shown by co-IP, functional readout via Wnt reporter, nuclear localization imaging, but single lab study\",\n      \"pmids\": [\"34058472\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PKP3 activates the mTOR pathway via interaction with upstream MAPK pathway components to regulate autophagy and invasion in ovarian cancer; silencing PKP3 decreased proliferation, colony formation, and invasion, while overexpression upregulated these activities.\",\n      \"method\": \"siRNA knockdown, overexpression, pathway inhibitor assays, cell proliferation/invasion assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — functional phenotype with pathway placement via western blot, single lab, no direct biochemical reconstitution of PKP3-MAPK interaction\",\n      \"pmids\": [\"30527804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"miR-149 directly decreases PKP3 expression; the carcinogen DNP upregulates miR-149 to suppress PKP3, thereby promoting NPC cell proliferation, adhesion, migration, and invasion; inhibition of miR-149 rescued PKP3 levels and blocked these pro-metastatic effects.\",\n      \"method\": \"miR-149 inhibitor rescue experiments, western blot, migration/invasion assays in NPC cell lines\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — functional rescue by miR-149 inhibitor implicates PKP3 as downstream target, but no direct validation of miR-149 binding site on PKP3 3'UTR reported\",\n      \"pmids\": [\"30144176\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"FERMT1 upregulates PKP3 expression and activates the p38 MAPK signaling pathway; knockdown of PKP3 counteracts the p38 MAPK activation induced by FERMT1 overexpression, placing PKP3 downstream of FERMT1 and upstream of p38 MAPK in a migration/invasion-promoting axis in NSCLC.\",\n      \"method\": \"siRNA knockdown of PKP3, FERMT1 overexpression, western blot for p38 MAPK pathway components, Transwell migration/invasion assays\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — genetic epistasis by knockdown/overexpression, single lab, no direct biochemical interaction between PKP3 and p38 MAPK shown\",\n      \"pmids\": [\"38200443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"miR-10b-5p directly targets the PKP3 3'UTR (validated by dual luciferase reporter assay) to suppress PKP3 expression; reduced PKP3 inhibits the RIPK3/MLKL necroptosis signaling pathway, promoting LUAD cell proliferation and suppressing necroptosis; PKP3 knockdown phenocopies miR-10b-5p overexpression and suppresses RIPK3/MLKL activation.\",\n      \"method\": \"Dual luciferase reporter assay, western blot (RIPK3/MLKL), siRNA knockdown of PKP3, miR-10b-5p overexpression/inhibition, xenograft mouse model\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — direct 3'UTR targeting validated by luciferase assay, pathway placement via multiple methods including in vivo model, single lab\",\n      \"pmids\": [\"40116080\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"circFOXK2 acts as a sponge for miR-328-5p to upregulate PKP3, thereby promoting NSCLC cell proliferation, migration, and invasion; direct binding between miR-328-5p and circFOXK2 was validated by dual luciferase reporter assay.\",\n      \"method\": \"Dual luciferase reporter assay, qRT-PCR, CCK-8 proliferation assay, wound healing and Transwell invasion assays\",\n      \"journal\": \"Cellular and molecular biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — sponge mechanism validated for circFOXK2/miR-328-5p but PKP3 as direct target of miR-328-5p not independently validated by luciferase; single lab\",\n      \"pmids\": [\"41351372\"],\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, demonstrated by luciferase reporter assays comparing methylated vs. unmethylated constructs; this region is hypermethylated in blood from cystic fibrosis patients with severe phenotype.\",\n      \"method\": \"Luciferase reporter assay with methylated and unmethylated PKP3 gene-body sequence in lung epithelial cells, bisulfite next-generation sequencing\",\n      \"journal\": \"Epigenetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct functional demonstration of methylation-dependent promoter activity by luciferase assay, single lab but mechanistically rigorous\",\n      \"pmids\": [\"34415821\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PKP3 augments ERCC1 expression by activating the MAPK pathway; CFDTW treatment reduces PKP3 expression by enhancing methylation of the PKP3 promoter, which promotes proliferation and reduces apoptosis in ovarian granulosa cells through the PKP3/MAPK/ERCC1 axis.\",\n      \"method\": \"PKP3 overexpression/knockdown, ERCC1 expression analysis, MAPK pathway western blot, promoter methylation analysis, cell proliferation/apoptosis assays\",\n      \"journal\": \"Journal of ovarian research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — pathway placement by overexpression/knockdown experiments, single lab, no direct biochemical demonstration of PKP3-MAPK interaction\",\n      \"pmids\": [\"37420272\"],\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 ligand, and translocating to the nucleus to stimulate Wnt target gene expression), activates downstream MAPK/p38 and mTOR pathways to promote cell proliferation and invasion, regulates necroptosis via the RIPK3/MLKL cascade, and is itself transcriptionally controlled by promoter methylation and post-transcriptionally suppressed by multiple miRNAs (miR-149, miR-10b-5p, miR-328-5p) acting through its 3'UTR.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"PKP3 is a plakophilin family member that functions beyond cell adhesion as a signaling intermediate linking Wnt, MAPK, and necroptosis pathways. PKP3 associates with the β-catenin destruction complex components GSK3β and Axin, is stabilized and translocates to the nucleus upon Wnt ligand stimulation, and activates Wnt-responsive transcription [PMID:34058472]. PKP3 also activates downstream MAPK/p38 and mTOR signaling to promote cell proliferation, invasion, and ERCC1 expression [PMID:30527804, PMID:38200443, PMID:37420272], and positively regulates RIPK3/MLKL-dependent necroptosis [PMID:40116080]. PKP3 expression is controlled by promoter/gene-body methylation [PMID:34415821] and is post-transcriptionally suppressed by miR-10b-5p, which directly targets its 3′-UTR [PMID:40116080], and by miR-149 [PMID:30144176].\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Establishing that PKP3 is not merely a structural desmosomal protein but an upstream activator of mTOR signaling that promotes cancer cell proliferation, invasion, and autophagy regulation in ovarian cancer.\",\n      \"evidence\": \"siRNA knockdown and overexpression with pathway inhibitors and proliferation/invasion assays in ovarian cancer cells\",\n      \"pmids\": [\"30527804\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct biochemical interaction between PKP3 and MAPK/mTOR components was demonstrated\",\n        \"Single cell-line context (ovarian cancer); generalizability unclear\",\n        \"Mechanism by which PKP3 engages MAPK pathway not resolved\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identifying PKP3 as a downstream target of miR-149 whose suppression by the carcinogen DNP promotes nasopharyngeal carcinoma cell migration and invasion, providing the first evidence for miRNA-mediated PKP3 regulation.\",\n      \"evidence\": \"miR-149 inhibitor rescue experiments and western blot in NPC cell lines treated with DNP\",\n      \"pmids\": [\"30144176\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Direct binding of miR-149 to the PKP3 3′-UTR was not validated by luciferase reporter assay\",\n        \"Mechanism linking PKP3 loss to enhanced invasion not delineated\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealing that PKP3 is a novel component of the canonical Wnt signaling cascade: it associates with the GSK3β/Axin destruction complex, is stabilized by Wnt ligand, translocates to the nucleus, and activates Wnt-responsive transcription—establishing PKP3 as a Wnt-responsive nuclear effector analogous to β-catenin.\",\n      \"evidence\": \"Co-immunoprecipitation of PKP3 with GSK3β and Axin, Wnt luciferase reporter assay, nuclear localization imaging upon Wnt stimulation or dominant-active LRP6\",\n      \"pmids\": [\"34058472\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether PKP3 directly binds TCF/LEF transcription factors in the nucleus is unknown\",\n        \"Not confirmed whether PKP3 is a direct phosphorylation substrate of GSK3β\",\n        \"Single lab study; independent replication lacking\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrating that a gene-body sequence within PKP3 possesses methylation-dependent promoter activity in lung epithelial cells, linking epigenetic regulation to PKP3 transcriptional control.\",\n      \"evidence\": \"Luciferase reporter assays comparing methylated vs. unmethylated PKP3 gene-body constructs in lung epithelial cells; bisulfite sequencing in cystic fibrosis patient blood\",\n      \"pmids\": [\"34415821\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether gene-body methylation regulates endogenous PKP3 protein levels in vivo is not shown\",\n        \"Transcription factors responsive to the methylation state of this region are unidentified\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extending the PKP3–MAPK axis by showing PKP3 augments ERCC1 expression through MAPK activation in ovarian granulosa cells, and that PKP3 promoter methylation controls this signaling cascade.\",\n      \"evidence\": \"PKP3 overexpression/knockdown with ERCC1 and MAPK western blot, promoter methylation analysis in granulosa cells\",\n      \"pmids\": [\"37420272\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct biochemical interaction between PKP3 and any MAPK component demonstrated\",\n        \"Single cell type; relevance to other tissues unclear\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placing PKP3 downstream of FERMT1 and upstream of p38 MAPK in an epistatic signaling axis that drives NSCLC migration and invasion, specifying p38 as the MAPK branch regulated by PKP3.\",\n      \"evidence\": \"siRNA knockdown of PKP3 reversing FERMT1-induced p38 MAPK activation; Transwell assays in NSCLC cells\",\n      \"pmids\": [\"38200443\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Direct physical interaction between PKP3 and p38 MAPK or its upstream kinases not shown\",\n        \"Whether FERMT1 directly regulates PKP3 transcription or protein stability is unknown\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Establishing PKP3 as a positive regulator of RIPK3/MLKL-dependent necroptosis and validating miR-10b-5p as a direct suppressor of PKP3 via its 3′-UTR, linking PKP3 loss to necroptosis evasion and tumor growth in LUAD.\",\n      \"evidence\": \"Dual luciferase reporter assay confirming miR-10b-5p targeting of PKP3 3′-UTR; PKP3 knockdown phenocopying miR-10b-5p overexpression; RIPK3/MLKL western blot; xenograft model\",\n      \"pmids\": [\"40116080\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether PKP3 directly binds RIPK3 or acts through an intermediary is unknown\",\n        \"Mechanism by which PKP3 activates the necroptosis cascade not resolved\",\n        \"Single cancer type studied (LUAD)\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identifying a circFOXK2/miR-328-5p/PKP3 regulatory axis that promotes NSCLC proliferation and invasion, adding another miRNA-mediated layer of PKP3 post-transcriptional control.\",\n      \"evidence\": \"Dual luciferase assay for circFOXK2–miR-328-5p interaction; qRT-PCR and functional assays in NSCLC cells\",\n      \"pmids\": [\"41351372\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Direct targeting of PKP3 3′-UTR by miR-328-5p not independently validated by luciferase assay\",\n        \"Whether circFOXK2 regulation of PKP3 occurs in non-cancer contexts is unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PKP3 biochemically activates MAPK/p38 and RIPK3/MLKL pathways—whether through direct binding or adaptor-mediated mechanisms—remains unresolved, as does the structural basis for its interaction with the Wnt destruction complex and whether it acts as a transcriptional co-activator in the nucleus.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural or reconstituted biochemical data for PKP3 interaction with any signaling partner\",\n        \"Whether PKP3 desmosomal and signaling functions are mutually exclusive or coordinated is unknown\",\n        \"No in vivo genetic models (knockout mice) characterizing PKP3 physiological function\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 3, 4]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GSK3B\",\n      \"AXIN1\",\n      \"RIPK3\",\n      \"MLKL\",\n      \"FERMT1\",\n      \"ERCC1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}