{"gene":"TCTN3","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2012,"finding":"TCTN3 is necessary for transduction of the Sonic Hedgehog (SHH) signaling pathway; truncating TCTN3 mutations in patient cells cause abnormal processing of GLI3, consistent with TCTN3's role at the ciliary transition zone where it forms a complex with TCTN1 and TCTN2.","method":"Patient cell analysis showing abnormal GLI3 processing; homozygosity mapping and exome sequencing to identify mutations","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — functional GLI3 processing assay in patient cells, replicated across multiple unrelated patient families, consistent with murine complex data","pmids":["22883145"],"is_preprint":false},{"year":2017,"finding":"Loss of Tctn3 in mice decreases ciliogenesis and Hh signaling, and causes holoprosencephaly, randomized heart looping, and loss of the floor plate. Overexpression of Tctn3, but not Tctn1 or Tctn2, rescues ciliogenesis in Tctn3 mutant cells, indicating functional non-redundancy for ciliogenesis. Replacement of Tctn3 with Tctn1 or Tctn2 impairs ciliogenesis and Hh signaling but surprisingly preserves neural tube patterning and Gli3 proteolytic processing into a repressor.","method":"Genetic knockout mice, gene replacement (knock-in) experiments, ciliogenesis rescue assays, neural tube patterning analysis, Gli3 processing western blot","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal genetic methods (KO, knock-in rescue, overexpression rescue) in a single rigorous study with defined cellular and developmental phenotypes","pmids":["28800946"],"is_preprint":false},{"year":2018,"finding":"Tctn3 knockout mice exhibit prenatal lethality, microphthalmia, polysyndactyly, and neural tube defects. Tctn3 KO disrupts the Shh signaling pathway (reduced Gli1 and Ptch1 mRNA, altered Shh/Foxa2/Nkx2.2 distribution) and induces neuronal apoptosis via alterations in Bcl-2, Bax, and cleaved PARP1. Tctn3 KO inhibits PI3K/Akt signaling (but not mTOR-dependent pathway), and apoptosis is rescued by Akt activator SC79. NPHP1 forms a protein complex with Tctn3 and its levels are decreased in Tctn3 KO mice.","method":"PiggyBac transposon-based Tctn3 knockout mice; western blotting for apoptosis and signaling proteins; qRT-PCR for Shh pathway targets; immunofluorescence for neural tube patterning; co-immunoprecipitation of NPHP1-Tctn3 complex; pharmacological rescue with SC79","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (KO model, Co-IP, pharmacological rescue, qRT-PCR, western blot) in a single study with defined molecular and cellular phenotypes","pmids":["29725084"],"is_preprint":false},{"year":2007,"finding":"Overexpression of C10orf61 (TCTN3) in HeLa cells induces apoptosis, as measured by increased percentage of apoptotic nuclei, DNA fragmentation, and activation of caspase-7 and PARP cleavage.","method":"Transient transfection overexpression screen; automated fluorescence microscopy for nuclear morphology; DNA fragmentation ELISA; western blotting for caspase-7 and PARP","journal":"Molecules and cells","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — multiple readouts (imaging, ELISA, western blot) but single lab, overexpression context, no endogenous loss-of-function validation","pmids":["17464193"],"is_preprint":false},{"year":2020,"finding":"TCTN3 mutation (c.1268G>A, p.Gly423Glu) in human pluripotent stem cell-derived cardiomyocytes consistently results in lower rate and weaker force of contraction compared to wild type.","method":"CRISPR/Cas9-generated hPSCs carrying TCTN3 mutation differentiated into cardiomyocytes; contractility assays; transcriptomic analysis","journal":"Journal of cellular and molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — CRISPR-engineered cell model with functional contractility readout, single lab, compound mutation context (LTBP2 also mutated)","pmids":["33098376"],"is_preprint":false},{"year":2020,"finding":"Inhibition of TCTN3 expression (by Cordyceps militaris extract) in non-small cell lung cancer cells suppresses Hedgehog signaling via the SMO/PTCH1 axis, reduces GLI1 nuclear translocation, and induces intrinsic apoptosis involving caspase activation and downregulation of Bcl-2 and Bcl-xL.","method":"CCK-8 proliferation assay; transmission electron microscopy; annexin V/PI apoptosis staining; immunoblotting for Hh pathway and apoptosis proteins; gene expression profiling","journal":"Integrative cancer therapies","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pharmacological inhibition of TCTN3 expression (indirect), single lab, no genetic KO or rescue validation of TCTN3 specifically","pmids":["32456485"],"is_preprint":false},{"year":2026,"finding":"STAT1 directly binds to the TCTN3 promoter to transcriptionally activate TCTN3 expression in papillary thyroid carcinoma cells; STAT1-TCTN3 axis drives cell-cycle progression (S-phase entry, Cyclin D1/CDK4/6 upregulation), migration, and invasion (MMP2/MMP9 upregulation, E-cadherin downregulation). No direct protein-protein interaction between STAT1 and TCTN3 was detected. TCTN3 re-expression rescues the phenotype of STAT1 depletion.","method":"Chromatin immunoprecipitation (ChIP); luciferase reporter assay; co-immunoprecipitation (negative for direct interaction); siRNA knockdown and overexpression; CCK-8, EdU, colony formation, flow cytometry, Transwell assays; xenograft mouse models","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and luciferase reporter confirm direct promoter binding, epistasis rescue experiment, multiple functional readouts, single lab","pmids":["41581815"],"is_preprint":false}],"current_model":"TCTN3 is a single-pass membrane protein that localizes to the transition zone of primary cilia as part of a complex with TCTN1 and TCTN2; it is required for ciliogenesis, proper Sonic Hedgehog/GLI3 signaling, and neural tube patterning, while interacting with NPHP1 to suppress apoptosis via PI3K/Akt, and its transcription is directly activated by STAT1 binding to its promoter in cancer contexts."},"narrative":{"mechanistic_narrative":"TCTN3 is a transition-zone component of primary cilia required for ciliogenesis and proper transduction of Sonic Hedgehog (SHH) signaling, where it functions in a complex with TCTN1 and TCTN2 and is needed for correct proteolytic processing of GLI3 [PMID:22883145]. Loss of Tctn3 in mice reduces ciliogenesis and Hh signaling and produces developmental patterning defects including holoprosencephaly, randomized heart looping, neural tube defects, and loss of the floor plate; notably, TCTN3 is functionally non-redundant with its paralogs, as only Tctn3 overexpression rescues ciliogenesis in mutant cells [PMID:28800946, PMID:29725084]. Mechanistically, Tctn3 disruption depresses the SHH transcriptional output (reduced Gli1 and Ptch1) and triggers neuronal apoptosis through inhibition of PI3K/Akt signaling, a phenotype reversible by Akt activation; TCTN3 forms a protein complex with NPHP1, whose levels fall upon Tctn3 loss [PMID:29725084]. Beyond its developmental role, TCTN3 is a transcriptional target of STAT1, which binds the TCTN3 promoter to drive cell-cycle progression, migration, and invasion in papillary thyroid carcinoma, with no direct STAT1-TCTN3 protein interaction [PMID:41581815]. Human truncating mutations in TCTN3 underlie a ciliopathy phenotype characterized by abnormal GLI3 processing [PMID:22883145].","teleology":[{"year":2007,"claim":"An early overexpression screen first implicated the uncharacterized C10orf61/TCTN3 gene product in cell-death control, before its ciliary function was known.","evidence":"Transient overexpression in HeLa cells with nuclear morphology imaging, DNA fragmentation ELISA, and caspase-7/PARP cleavage western blots","pmids":["17464193"],"confidence":"Medium","gaps":["Overexpression context without endogenous loss-of-function validation","No link to ciliary or Hedgehog function established at this stage","Single lab, single cell line"]},{"year":2012,"claim":"Identification of truncating TCTN3 mutations in patients established the gene as a transition-zone ciliopathy factor required for SHH transduction, answering whether TCTN3 has a defined developmental signaling role.","evidence":"Homozygosity mapping and exome sequencing in patient families plus GLI3 processing assays in patient cells","pmids":["22883145"],"confidence":"High","gaps":["Molecular basis of TCTN3 contribution to the TCTN1/2/3 complex not resolved","Mechanism by which transition-zone localization controls GLI3 processing not defined"]},{"year":2017,"claim":"Genetic knockout and gene-replacement experiments showed TCTN3 is functionally non-redundant for ciliogenesis and dissected the relationship between ciliogenesis, Hh signaling, and neural tube patterning.","evidence":"Knockout mice, knock-in paralog-replacement, ciliogenesis rescue assays, neural tube patterning analysis, and Gli3 processing western blots","pmids":["28800946"],"confidence":"High","gaps":["Why neural tube patterning and Gli3 repressor formation are preserved upon paralog replacement while ciliogenesis fails is unexplained","Structural basis for paralog non-redundancy not determined"]},{"year":2018,"claim":"A second knockout model connected TCTN3 loss to neuronal apoptosis through PI3K/Akt suppression and identified NPHP1 as a TCTN3 complex partner, linking the ciliary protein to a survival pathway.","evidence":"PiggyBac knockout mice with western blotting, qRT-PCR of Shh targets, immunofluorescence, NPHP1-Tctn3 co-immunoprecipitation, and SC79 pharmacological rescue","pmids":["29725084"],"confidence":"High","gaps":["Direct mechanistic link between TCTN3, NPHP1, and PI3K/Akt activation not defined","Whether apoptosis is a direct consequence or downstream of impaired Hh signaling unresolved"]},{"year":2020,"claim":"Disease-modeling and cancer studies extended TCTN3 function to cardiomyocyte contractility and to Hedgehog-dependent tumor cell survival.","evidence":"CRISPR-engineered hPSC-derived cardiomyocyte contractility assays; pharmacological suppression of TCTN3 in NSCLC cells with apoptosis and Hh-pathway readouts","pmids":["33098376","32456485"],"confidence":"Low","gaps":["Cardiomyocyte phenotype confounded by a co-occurring LTBP2 mutation","NSCLC study uses indirect pharmacological inhibition without genetic TCTN3 knockout or rescue","TCTN3 specificity of the cancer phenotype not isolated"]},{"year":2026,"claim":"TCTN3 was placed downstream of a transcriptional regulator, with STAT1 directly activating TCTN3 to drive proliferation and invasion in thyroid carcinoma.","evidence":"ChIP and luciferase reporter assays for promoter binding, negative co-IP for direct interaction, siRNA/overexpression epistasis rescue, multiple proliferation/migration assays, and xenografts","pmids":["41581815"],"confidence":"Medium","gaps":["Mechanism by which TCTN3 drives cell-cycle and invasion programs downstream of its ciliary role not defined","Single lab; generalizability beyond papillary thyroid carcinoma unknown"]},{"year":null,"claim":"How TCTN3's transition-zone scaffolding activity is mechanistically coupled to GLI3 processing, PI3K/Akt-dependent survival, and its non-ciliary oncogenic outputs remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of the TCTN1/TCTN2/TCTN3 transition-zone complex in the corpus","Direct biochemical activity of TCTN3 not established","Causal chain linking ciliary defects to apoptosis versus tumor-promoting phenotypes not unified"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[0,1]},{"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":[0,1,2]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[2,3]}],"complexes":["Tectonic (TCTN1/TCTN2/TCTN3) transition-zone complex"],"partners":["TCTN1","TCTN2","NPHP1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6NUS6","full_name":"Tectonic-3","aliases":[],"length_aa":607,"mass_kda":66.2,"function":"Part of the tectonic-like complex which is required for tissue-specific ciliogenesis and may regulate ciliary membrane composition (By similarity). May be involved in apoptosis regulation. Necessary for signal transduction through the sonic hedgehog (Shh) signaling pathway","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q6NUS6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TCTN3","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CANX","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/TCTN3","total_profiled":1310},"omim":[{"mim_id":"614815","title":"JOUBERT SYNDROME 18; JBTS18","url":"https://www.omim.org/entry/614815"},{"mim_id":"613847","title":"TECTONIC FAMILY, MEMBER 3; TCTN3","url":"https://www.omim.org/entry/613847"},{"mim_id":"613846","title":"TECTONIC FAMILY, MEMBER 2; TCTN2","url":"https://www.omim.org/entry/613846"},{"mim_id":"609863","title":"TECTONIC FAMILY, MEMBER 1; TCTN1","url":"https://www.omim.org/entry/609863"},{"mim_id":"258860","title":"OROFACIODIGITAL SYNDROME IV; OFD4","url":"https://www.omim.org/entry/258860"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Microtubules","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TCTN3"},"hgnc":{"alias_symbol":["DKFZP564D116","TECT3","JBTS18"],"prev_symbol":["C10orf61"]},"alphafold":{"accession":"Q6NUS6","domains":[{"cath_id":"-","chopping":"129-164","consensus_level":"medium","plddt":75.6056,"start":129,"end":164},{"cath_id":"-","chopping":"206-370","consensus_level":"medium","plddt":87.1178,"start":206,"end":370},{"cath_id":"-","chopping":"379-553","consensus_level":"medium","plddt":85.739,"start":379,"end":553}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6NUS6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6NUS6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6NUS6-F1-predicted_aligned_error_v6.png","plddt_mean":71.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TCTN3","jax_strain_url":"https://www.jax.org/strain/search?query=TCTN3"},"sequence":{"accession":"Q6NUS6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6NUS6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6NUS6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6NUS6"}},"corpus_meta":[{"pmid":"22883145","id":"PMC_22883145","title":"TCTN3 mutations cause Mohr-Majewski syndrome.","date":"2012","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/22883145","citation_count":107,"is_preprint":false},{"pmid":"32139166","id":"PMC_32139166","title":"Clinical and Molecular Diagnosis of Joubert Syndrome and Related Disorders.","date":"2020","source":"Pediatric neurology","url":"https://pubmed.ncbi.nlm.nih.gov/32139166","citation_count":62,"is_preprint":false},{"pmid":"23972372","id":"PMC_23972372","title":"Mutations in DDX59 implicate RNA helicase in the pathogenesis of orofaciodigital syndrome.","date":"2013","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23972372","citation_count":46,"is_preprint":false},{"pmid":"29725084","id":"PMC_29725084","title":"Loss of Tctn3 causes neuronal apoptosis and neural tube defects in mice.","date":"2018","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/29725084","citation_count":42,"is_preprint":false},{"pmid":"25118024","id":"PMC_25118024","title":"Tectonic gene mutations in patients with Joubert syndrome.","date":"2014","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/25118024","citation_count":30,"is_preprint":false},{"pmid":"28800946","id":"PMC_28800946","title":"Three Tctn proteins are functionally conserved in the regulation of neural tube patterning and Gli3 processing but not ciliogenesis and Hedgehog signaling in the mouse.","date":"2017","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/28800946","citation_count":18,"is_preprint":false},{"pmid":"30286481","id":"PMC_30286481","title":"Tectonic Proteins Are Important Players in Non-Motile Ciliopathies.","date":"2018","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/30286481","citation_count":15,"is_preprint":false},{"pmid":"32456485","id":"PMC_32456485","title":"Cordyceps militaris Exerts Anticancer Effect on Non-Small Cell Lung Cancer by Inhibiting Hedgehog Signaling via Suppression of TCTN3.","date":"2020","source":"Integrative cancer therapies","url":"https://pubmed.ncbi.nlm.nih.gov/32456485","citation_count":14,"is_preprint":false},{"pmid":"17464193","id":"PMC_17464193","title":"Identification of novel regulators of apoptosis using a high-throughput cell-based screen.","date":"2007","source":"Molecules and cells","url":"https://pubmed.ncbi.nlm.nih.gov/17464193","citation_count":12,"is_preprint":false},{"pmid":"29458881","id":"PMC_29458881","title":"Prenatal diagnosis of short-rib polydactyly syndrome type III or short-rib thoracic dysplasia 3 with or without polydactyly (SRTD3) associated with compound heterozygous mutations in DYNC2H1 in a fetus.","date":"2018","source":"Taiwanese journal of obstetrics & gynecology","url":"https://pubmed.ncbi.nlm.nih.gov/29458881","citation_count":12,"is_preprint":false},{"pmid":"33098376","id":"PMC_33098376","title":"Novel mutations of TCTN3/LTBP2 with cellular function changes in congenital heart disease associated with polydactyly.","date":"2020","source":"Journal of cellular and molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33098376","citation_count":11,"is_preprint":false},{"pmid":"34096792","id":"PMC_34096792","title":"Meckel-Gruber Syndrome: Clinical and Molecular Genetic Profiles in Two Fetuses and Review of the Current Literature.","date":"2021","source":"Genetic testing and molecular biomarkers","url":"https://pubmed.ncbi.nlm.nih.gov/34096792","citation_count":8,"is_preprint":false},{"pmid":"35751429","id":"PMC_35751429","title":"De novo heterozygous variants in SLC30A7 are a candidate cause for Joubert syndrome.","date":"2022","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/35751429","citation_count":7,"is_preprint":false},{"pmid":"31816441","id":"PMC_31816441","title":"A new case of KIAA0753-related variant of Jeune asphyxiating thoracic dystrophy.","date":"2019","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31816441","citation_count":7,"is_preprint":false},{"pmid":"40565597","id":"PMC_40565597","title":"Expansion of the Genotypic and Phenotypic Spectrum of TCTN3-Related Joubert Syndrome.","date":"2025","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/40565597","citation_count":1,"is_preprint":false},{"pmid":"40008080","id":"PMC_40008080","title":"Screening and Validation of Potential Biomarkers of Immune Cells in Childhood Asthma Patients via Mendelian Randomization and Machine Learning.","date":"2025","source":"Journal of inflammation research","url":"https://pubmed.ncbi.nlm.nih.gov/40008080","citation_count":1,"is_preprint":false},{"pmid":"41581815","id":"PMC_41581815","title":"STAT1-TCTN3 axis drives papillary thyroid carcinoma progression by accelerating the cell cycle and promoting tumor cell migration and invasion.","date":"2026","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/41581815","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11200,"output_tokens":2081,"usd":0.032407,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9036,"output_tokens":2726,"usd":0.056665,"stage2_stop_reason":"end_turn"},"total_usd":0.089072,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2012,\n      \"finding\": \"TCTN3 is necessary for transduction of the Sonic Hedgehog (SHH) signaling pathway; truncating TCTN3 mutations in patient cells cause abnormal processing of GLI3, consistent with TCTN3's role at the ciliary transition zone where it forms a complex with TCTN1 and TCTN2.\",\n      \"method\": \"Patient cell analysis showing abnormal GLI3 processing; homozygosity mapping and exome sequencing to identify mutations\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — functional GLI3 processing assay in patient cells, replicated across multiple unrelated patient families, consistent with murine complex data\",\n      \"pmids\": [\"22883145\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Loss of Tctn3 in mice decreases ciliogenesis and Hh signaling, and causes holoprosencephaly, randomized heart looping, and loss of the floor plate. Overexpression of Tctn3, but not Tctn1 or Tctn2, rescues ciliogenesis in Tctn3 mutant cells, indicating functional non-redundancy for ciliogenesis. Replacement of Tctn3 with Tctn1 or Tctn2 impairs ciliogenesis and Hh signaling but surprisingly preserves neural tube patterning and Gli3 proteolytic processing into a repressor.\",\n      \"method\": \"Genetic knockout mice, gene replacement (knock-in) experiments, ciliogenesis rescue assays, neural tube patterning analysis, Gli3 processing western blot\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal genetic methods (KO, knock-in rescue, overexpression rescue) in a single rigorous study with defined cellular and developmental phenotypes\",\n      \"pmids\": [\"28800946\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Tctn3 knockout mice exhibit prenatal lethality, microphthalmia, polysyndactyly, and neural tube defects. Tctn3 KO disrupts the Shh signaling pathway (reduced Gli1 and Ptch1 mRNA, altered Shh/Foxa2/Nkx2.2 distribution) and induces neuronal apoptosis via alterations in Bcl-2, Bax, and cleaved PARP1. Tctn3 KO inhibits PI3K/Akt signaling (but not mTOR-dependent pathway), and apoptosis is rescued by Akt activator SC79. NPHP1 forms a protein complex with Tctn3 and its levels are decreased in Tctn3 KO mice.\",\n      \"method\": \"PiggyBac transposon-based Tctn3 knockout mice; western blotting for apoptosis and signaling proteins; qRT-PCR for Shh pathway targets; immunofluorescence for neural tube patterning; co-immunoprecipitation of NPHP1-Tctn3 complex; pharmacological rescue with SC79\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (KO model, Co-IP, pharmacological rescue, qRT-PCR, western blot) in a single study with defined molecular and cellular phenotypes\",\n      \"pmids\": [\"29725084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Overexpression of C10orf61 (TCTN3) in HeLa cells induces apoptosis, as measured by increased percentage of apoptotic nuclei, DNA fragmentation, and activation of caspase-7 and PARP cleavage.\",\n      \"method\": \"Transient transfection overexpression screen; automated fluorescence microscopy for nuclear morphology; DNA fragmentation ELISA; western blotting for caspase-7 and PARP\",\n      \"journal\": \"Molecules and cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — multiple readouts (imaging, ELISA, western blot) but single lab, overexpression context, no endogenous loss-of-function validation\",\n      \"pmids\": [\"17464193\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TCTN3 mutation (c.1268G>A, p.Gly423Glu) in human pluripotent stem cell-derived cardiomyocytes consistently results in lower rate and weaker force of contraction compared to wild type.\",\n      \"method\": \"CRISPR/Cas9-generated hPSCs carrying TCTN3 mutation differentiated into cardiomyocytes; contractility assays; transcriptomic analysis\",\n      \"journal\": \"Journal of cellular and molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — CRISPR-engineered cell model with functional contractility readout, single lab, compound mutation context (LTBP2 also mutated)\",\n      \"pmids\": [\"33098376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Inhibition of TCTN3 expression (by Cordyceps militaris extract) in non-small cell lung cancer cells suppresses Hedgehog signaling via the SMO/PTCH1 axis, reduces GLI1 nuclear translocation, and induces intrinsic apoptosis involving caspase activation and downregulation of Bcl-2 and Bcl-xL.\",\n      \"method\": \"CCK-8 proliferation assay; transmission electron microscopy; annexin V/PI apoptosis staining; immunoblotting for Hh pathway and apoptosis proteins; gene expression profiling\",\n      \"journal\": \"Integrative cancer therapies\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pharmacological inhibition of TCTN3 expression (indirect), single lab, no genetic KO or rescue validation of TCTN3 specifically\",\n      \"pmids\": [\"32456485\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"STAT1 directly binds to the TCTN3 promoter to transcriptionally activate TCTN3 expression in papillary thyroid carcinoma cells; STAT1-TCTN3 axis drives cell-cycle progression (S-phase entry, Cyclin D1/CDK4/6 upregulation), migration, and invasion (MMP2/MMP9 upregulation, E-cadherin downregulation). No direct protein-protein interaction between STAT1 and TCTN3 was detected. TCTN3 re-expression rescues the phenotype of STAT1 depletion.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP); luciferase reporter assay; co-immunoprecipitation (negative for direct interaction); siRNA knockdown and overexpression; CCK-8, EdU, colony formation, flow cytometry, Transwell assays; xenograft mouse models\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and luciferase reporter confirm direct promoter binding, epistasis rescue experiment, multiple functional readouts, single lab\",\n      \"pmids\": [\"41581815\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TCTN3 is a single-pass membrane protein that localizes to the transition zone of primary cilia as part of a complex with TCTN1 and TCTN2; it is required for ciliogenesis, proper Sonic Hedgehog/GLI3 signaling, and neural tube patterning, while interacting with NPHP1 to suppress apoptosis via PI3K/Akt, and its transcription is directly activated by STAT1 binding to its promoter in cancer contexts.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TCTN3 is a transition-zone component of primary cilia required for ciliogenesis and proper transduction of Sonic Hedgehog (SHH) signaling, where it functions in a complex with TCTN1 and TCTN2 and is needed for correct proteolytic processing of GLI3 [#0]. Loss of Tctn3 in mice reduces ciliogenesis and Hh signaling and produces developmental patterning defects including holoprosencephaly, randomized heart looping, neural tube defects, and loss of the floor plate; notably, TCTN3 is functionally non-redundant with its paralogs, as only Tctn3 overexpression rescues ciliogenesis in mutant cells [#1, #2]. Mechanistically, Tctn3 disruption depresses the SHH transcriptional output (reduced Gli1 and Ptch1) and triggers neuronal apoptosis through inhibition of PI3K/Akt signaling, a phenotype reversible by Akt activation; TCTN3 forms a protein complex with NPHP1, whose levels fall upon Tctn3 loss [#2]. Beyond its developmental role, TCTN3 is a transcriptional target of STAT1, which binds the TCTN3 promoter to drive cell-cycle progression, migration, and invasion in papillary thyroid carcinoma, with no direct STAT1-TCTN3 protein interaction [#6]. Human truncating mutations in TCTN3 underlie a ciliopathy phenotype characterized by abnormal GLI3 processing [#0].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"An early overexpression screen first implicated the uncharacterized C10orf61/TCTN3 gene product in cell-death control, before its ciliary function was known.\",\n      \"evidence\": \"Transient overexpression in HeLa cells with nuclear morphology imaging, DNA fragmentation ELISA, and caspase-7/PARP cleavage western blots\",\n      \"pmids\": [\"17464193\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Overexpression context without endogenous loss-of-function validation\",\n        \"No link to ciliary or Hedgehog function established at this stage\",\n        \"Single lab, single cell line\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identification of truncating TCTN3 mutations in patients established the gene as a transition-zone ciliopathy factor required for SHH transduction, answering whether TCTN3 has a defined developmental signaling role.\",\n      \"evidence\": \"Homozygosity mapping and exome sequencing in patient families plus GLI3 processing assays in patient cells\",\n      \"pmids\": [\"22883145\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular basis of TCTN3 contribution to the TCTN1/2/3 complex not resolved\",\n        \"Mechanism by which transition-zone localization controls GLI3 processing not defined\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Genetic knockout and gene-replacement experiments showed TCTN3 is functionally non-redundant for ciliogenesis and dissected the relationship between ciliogenesis, Hh signaling, and neural tube patterning.\",\n      \"evidence\": \"Knockout mice, knock-in paralog-replacement, ciliogenesis rescue assays, neural tube patterning analysis, and Gli3 processing western blots\",\n      \"pmids\": [\"28800946\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Why neural tube patterning and Gli3 repressor formation are preserved upon paralog replacement while ciliogenesis fails is unexplained\",\n        \"Structural basis for paralog non-redundancy not determined\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"A second knockout model connected TCTN3 loss to neuronal apoptosis through PI3K/Akt suppression and identified NPHP1 as a TCTN3 complex partner, linking the ciliary protein to a survival pathway.\",\n      \"evidence\": \"PiggyBac knockout mice with western blotting, qRT-PCR of Shh targets, immunofluorescence, NPHP1-Tctn3 co-immunoprecipitation, and SC79 pharmacological rescue\",\n      \"pmids\": [\"29725084\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct mechanistic link between TCTN3, NPHP1, and PI3K/Akt activation not defined\",\n        \"Whether apoptosis is a direct consequence or downstream of impaired Hh signaling unresolved\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Disease-modeling and cancer studies extended TCTN3 function to cardiomyocyte contractility and to Hedgehog-dependent tumor cell survival.\",\n      \"evidence\": \"CRISPR-engineered hPSC-derived cardiomyocyte contractility assays; pharmacological suppression of TCTN3 in NSCLC cells with apoptosis and Hh-pathway readouts\",\n      \"pmids\": [\"33098376\", \"32456485\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Cardiomyocyte phenotype confounded by a co-occurring LTBP2 mutation\",\n        \"NSCLC study uses indirect pharmacological inhibition without genetic TCTN3 knockout or rescue\",\n        \"TCTN3 specificity of the cancer phenotype not isolated\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"TCTN3 was placed downstream of a transcriptional regulator, with STAT1 directly activating TCTN3 to drive proliferation and invasion in thyroid carcinoma.\",\n      \"evidence\": \"ChIP and luciferase reporter assays for promoter binding, negative co-IP for direct interaction, siRNA/overexpression epistasis rescue, multiple proliferation/migration assays, and xenografts\",\n      \"pmids\": [\"41581815\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which TCTN3 drives cell-cycle and invasion programs downstream of its ciliary role not defined\",\n        \"Single lab; generalizability beyond papillary thyroid carcinoma unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TCTN3's transition-zone scaffolding activity is mechanistically coupled to GLI3 processing, PI3K/Akt-dependent survival, and its non-ciliary oncogenic outputs remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural model of the TCTN1/TCTN2/TCTN3 transition-zone complex in the corpus\",\n        \"Direct biochemical activity of TCTN3 not established\",\n        \"Causal chain linking ciliary defects to apoptosis versus tumor-promoting phenotypes not unified\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"complexes\": [\"Tectonic (TCTN1/TCTN2/TCTN3) transition-zone complex\"],\n    \"partners\": [\"TCTN1\", \"TCTN2\", \"NPHP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}