{"gene":"TUBG1","run_date":"2026-06-10T10:51:56","timeline":{"discoveries":[{"year":2013,"finding":"Suppression of mouse Tubg1 expression in vivo (in utero) interferes with proper neuronal migration, establishing a role for γ-tubulin in postmitotic neuronal positioning during cortical development. Additionally, expression of pathogenic TUBG1 missense variants in Saccharomyces cerevisiae disrupts normal microtubule behavior, indicating the mutations act on microtubule dynamics.","method":"In vivo mouse Tubg1 knockdown (shRNA), yeast microtubule behavior assay with mutant γ-tubulin expression","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo loss-of-function with specific neuronal migration phenotype replicated in two model organisms, published in high-impact journal","pmids":["23603762"],"is_preprint":false},{"year":2019,"finding":"Pathogenic TUBG1 missense variants (including Y92C) disrupt neuronal locomotion (postmitotic neuronal migration) and reduce microtubule dynamics in subject-derived fibroblasts without causing major structural or functional centrosome defects. Centrosomal positioning in bipolar neurons is correct but neurons fail to initiate locomotion. A knock-in Tubg1Y92C/+ mouse model recapitulates neuroanatomical and behavioral defects and increased epileptic cortical activity.","method":"In utero electroporation, knock-in mouse model (Tubg1Y92C/+), live-cell microtubule dynamics assay in patient-derived fibroblasts, behavioral and EEG phenotyping","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (in vivo electroporation, knock-in mouse, patient fibroblast microtubule dynamics), single lab with rigorous controls","pmids":["31086189"],"is_preprint":false},{"year":2023,"finding":"TUBG1 forms a meshwork structure in mammalian cells; centrosome movements occur preferentially in cellular sites rich in GTPase TUBG1, and sgRNA-mediated reduction of TUBG1 expression alters the motility pattern of centrosomes, indicating the TUBG1 meshwork provides an interacting platform that mediates centrosome positional changes.","method":"Live-cell imaging with GFP-tagged TUBG1 and mRFP-tagged centrin 2, sgRNA-mediated TUBG1 knockdown, centrosome tracking","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct live-imaging localization tied to functional centrosome motility consequence, single lab, two orthogonal approaches (imaging + genetic knockdown)","pmids":["37685969"],"is_preprint":false},{"year":2025,"finding":"TUBG1 depletion via sgRNA disrupts microtubule, vimentin, and lamin B networks while reinforcing actin filament structures. Expression of N-terminal (TUBG1-335) or C-terminal (TUBG334-451) fragments of TUBG1 partially restores these networks, with the C-terminal fragment more effective at reestablishing microtubule integrity and both fragments stabilizing vimentin filaments and the nuclear envelope, demonstrating dual structural and regulatory roles for TUBG1 across multiple cytoskeletal systems.","method":"sgRNA-mediated TUBG1 knockdown, expression of TUBG1 domain fragments, immunofluorescence of cytoskeletal components","journal":"Heliyon","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — loss-of-function with defined cytoskeletal phenotype and domain-mapping rescue, single lab, multiple cytoskeletal readouts","pmids":["40013266"],"is_preprint":false},{"year":2024,"finding":"Somatic tubg1 mutation in zebrafish disrupts neurogenesis and brain development, mirroring microcephaly phenotypes, and γ-tubulin deficiency impairs canonical Wnt/β-catenin signaling activity, suggesting a regulatory link between γ-tubulin and Wnt signaling in brain development.","method":"Zebrafish somatic CRISPR/Cas9 tubg1 mutant model, Wnt/β-catenin reporter assay, neurogenesis and brain morphology analysis","journal":"Molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — in vivo loss-of-function with defined phenotype and Wnt pathway readout, single lab, two orthogonal phenotypic assessments","pmids":["39215931"],"is_preprint":false},{"year":2025,"finding":"TUBG1 operates in an E2F1-RB1 network; a small-molecule inhibitor (L12) targeting TUBG1 (but not TUBG2) enhances RB1 expression and selectively kills RB1-deficient tumor cells via E2F1-mediated upregulation of procaspase 3 and subsequent apoptosis. L12 cytotoxicity is attenuated by reduced E2F1 expression and demonstrates antitumor efficacy in xenografted small cell lung cancer models.","method":"Small-molecule TUBG1 inhibitor treatment, RB1/E2F1/procaspase-3 Western blotting, E2F1 knockdown rescue experiment, xenograft tumor model","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis (E2F1 knockdown rescue) combined with in vivo xenograft and pathway-level mechanistic readouts, single lab","pmids":["40019206"],"is_preprint":false},{"year":2023,"finding":"Silencing TUBG1 in hepatocellular carcinoma cell lines increases G1 arrest, inhibits proliferation and invasion, promotes apoptosis, and upregulates ATR, P-P38MAPK, P-P53, Bax, cleaved caspase 3, and P21 while downregulating Bcl-2, cyclin D1, cyclin E2, CDK2, and CDK4, placing TUBG1 upstream of the ATR/P53 apoptosis and cyclin-CDK cell cycle pathways.","method":"siRNA-mediated TUBG1 silencing in HCC cell lines, flow cytometry, colony formation, Western blotting of pathway components","journal":"Hepatobiliary & pancreatic diseases international","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — loss-of-function with multiple downstream pathway readouts, single lab, several orthogonal assays","pmids":["37806848"],"is_preprint":false}],"current_model":"TUBG1 encodes γ-tubulin, a GTPase component of the γ-tubulin ring complex (γ-TuRC) that nucleates microtubules at the centrosome/MTOC; pathogenic missense variants reduce microtubule dynamics and impair postmitotic neuronal locomotion during cortical development without disrupting centrosome structure, the TUBG1 meshwork provides a platform for centrosome motility, and TUBG1 also coordinates a broader cytoskeletal network (microtubules, vimentin, lamin B) and participates in an E2F1-RB1 cell-cycle/apoptosis network in tumor cells."},"narrative":{"mechanistic_narrative":"TUBG1 encodes γ-tubulin, a GTPase that organizes microtubule architecture and is essential for postmitotic neuronal positioning during cortical development [PMID:23603762]. Pathogenic missense variants, including Y92C, reduce microtubule dynamics and impair neuronal locomotion—bipolar neurons position their centrosomes correctly but fail to initiate migration—without producing major structural centrosome defects, and a knock-in mouse recapitulates the neuroanatomical, behavioral, and epileptic phenotypes, establishing TUBG1 as a cause of cortical malformation [PMID:31086189]. In mammalian cells TUBG1 assembles into a meshwork that serves as an interacting platform directing centrosome motility [PMID:37685969], and its activity extends beyond microtubules to maintain vimentin and lamin B networks while restraining actin, with N- and C-terminal fragments separably restoring these systems [PMID:40013266]. In disease contexts, γ-tubulin loss impairs canonical Wnt/β-catenin signaling during brain development [PMID:39215931] and operates within an E2F1–RB1 axis: pharmacological TUBG1 inhibition elevates RB1, drives E2F1-mediated procaspase-3 upregulation, and selectively kills RB1-deficient tumor cells [PMID:40019206], consistent with TUBG1 silencing triggering G1 arrest and ATR/P53-dependent apoptosis in carcinoma cells [PMID:37806848].","teleology":[{"year":2013,"claim":"Established that γ-tubulin is required not only for cell division but specifically for postmitotic neuronal migration in the developing cortex, and that disease variants act through microtubule dynamics.","evidence":"In vivo mouse Tubg1 knockdown (shRNA) plus mutant γ-tubulin expression in yeast microtubule assay","pmids":["23603762"],"confidence":"High","gaps":["Did not resolve whether the migration defect reflects loss of nucleation versus altered dynamics","No structural mapping of variant effects"]},{"year":2019,"claim":"Defined the cellular defect underlying TUBG1-linked malformation: reduced microtubule dynamics impair locomotion initiation despite correct centrosome positioning and intact centrosome function.","evidence":"In utero electroporation, Tubg1Y92C/+ knock-in mouse, live microtubule dynamics in patient fibroblasts, EEG/behavioral phenotyping","pmids":["31086189"],"confidence":"High","gaps":["Mechanism linking reduced dynamics to locomotion failure not resolved","Centrosome-independent function only inferred, not directly assayed at molecular level"]},{"year":2023,"claim":"Showed TUBG1 forms a cellular meshwork that functions as a positional platform for centrosome movement, extending its role beyond a punctate nucleation site.","evidence":"Live-cell imaging of GFP-TUBG1 and mRFP-centrin 2 with sgRNA knockdown and centrosome tracking","pmids":["37685969"],"confidence":"Medium","gaps":["Molecular composition of the meshwork not defined","Single lab, two approaches","How the meshwork mechanically couples to centrosomes unknown"]},{"year":2023,"claim":"Placed TUBG1 upstream of cell-cycle and apoptosis control in carcinoma cells, linking its loss to G1 arrest via cyclin-CDK suppression and ATR/P53-dependent apoptosis.","evidence":"siRNA silencing in HCC cell lines with flow cytometry, colony formation, and Western blot of pathway components","pmids":["37806848"],"confidence":"Medium","gaps":["Correlative pathway readouts without direct epistasis","Single lab","Whether effects are direct or secondary to mitotic disruption unclear"]},{"year":2024,"claim":"Connected γ-tubulin to a signaling pathway, showing its deficiency impairs canonical Wnt/β-catenin activity during brain development and microcephaly phenotypes.","evidence":"Zebrafish somatic CRISPR/Cas9 tubg1 mutant with Wnt/β-catenin reporter and neurogenesis analysis","pmids":["39215931"],"confidence":"Medium","gaps":["Mechanistic link between γ-tubulin and Wnt signaling not defined","Whether Wnt effect is cytoskeleton-dependent unknown"]},{"year":2025,"claim":"Demonstrated paralog-selective druggability of TUBG1 within an E2F1-RB1 network, enabling selective killing of RB1-deficient tumors via procaspase-3 upregulation.","evidence":"Small-molecule TUBG1 inhibitor (L12), RB1/E2F1/procaspase-3 Western blot, E2F1 knockdown rescue, SCLC xenograft","pmids":["40019206"],"confidence":"Medium","gaps":["Direct target engagement of L12 with TUBG1 not structurally confirmed","Mechanism by which TUBG1 inhibition elevates RB1 unresolved"]},{"year":2025,"claim":"Broadened TUBG1's structural role beyond microtubules, showing it coordinates vimentin and lamin B networks and that distinct termini carry separable structural functions.","evidence":"sgRNA knockdown with N- and C-terminal fragment rescue and immunofluorescence of cytoskeletal components","pmids":["40013266"],"confidence":"Medium","gaps":["Direct binding to vimentin/lamin B not demonstrated","Single lab","Whether intermediate-filament effects are direct or secondary to microtubule loss unclear"]},{"year":null,"claim":"The molecular mechanism by which γ-tubulin coordinates multiple cytoskeletal systems and intersects Wnt and E2F1-RB1 signaling remains undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the TUBG1 meshwork","Direct partners outside the microtubule system not identified","Causal link between cytoskeletal and signaling roles unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[2]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[3]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,1,3]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[2]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[6]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1,4]}],"complexes":[],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P23258","full_name":"Tubulin gamma-1 chain","aliases":["Gamma-1-tubulin","Gamma-tubulin complex component 1","GCP-1"],"length_aa":451,"mass_kda":51.2,"function":"Tubulin is the major constituent of microtubules, protein filaments consisting of alpha- and beta-tubulin heterodimers (PubMed:38305685, PubMed:38609661, PubMed:39321809). Gamma-tubulin is a key component of the gamma-tubulin ring complex (gTuRC) which mediates microtubule nucleation (PubMed:38305685, PubMed:38609661, PubMed:39321809). The gTuRC regulates the minus-end nucleation of alpha-beta tubulin heterodimers that grow into microtubule protafilaments, a critical step in centrosome duplication and spindle formation (PubMed:38305685, PubMed:38609661, PubMed:39321809)","subcellular_location":"Cytoplasm, cytoskeleton, microtubule organizing center, centrosome; Cytoplasm, cytoskeleton, spindle","url":"https://www.uniprot.org/uniprotkb/P23258/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/TUBG1","classification":"Common Essential","n_dependent_lines":1191,"n_total_lines":1208,"dependency_fraction":0.9859271523178808},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000131462","cell_line_id":"CID000723","localizations":[{"compartment":"centrosome","grade":3},{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":3}],"interactors":[{"gene":"TUBG1;TUBG2","stoichiometry":10.0},{"gene":"TUBGCP4","stoichiometry":4.0},{"gene":"NEDD1","stoichiometry":0.2},{"gene":"ANGPT1","stoichiometry":0.2},{"gene":"NME7","stoichiometry":0.2},{"gene":"TUBGCP3","stoichiometry":0.2},{"gene":"TUBGCP2","stoichiometry":0.2},{"gene":"ZC3H11A","stoichiometry":0.2},{"gene":"MZT2B;MZT2A","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000723","total_profiled":1310},"omim":[{"mim_id":"617720","title":"PROTEIN PHOSPHATASE 1, REGULATORY SUBUNIT 42; PPP1R42","url":"https://www.omim.org/entry/617720"},{"mim_id":"617140","title":"ZTTK SYNDROME; ZTTKS","url":"https://www.omim.org/entry/617140"},{"mim_id":"616899","title":"TBC1 DOMAIN-CONTAINING KINASE; TBCK","url":"https://www.omim.org/entry/616899"},{"mim_id":"616475","title":"CENTROSOMAL PROTEIN, 72-KD; CEP72","url":"https://www.omim.org/entry/616475"},{"mim_id":"616426","title":"CENTROSOMAL PROTEIN, 192-KD; CEP192","url":"https://www.omim.org/entry/616426"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Principal piece","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"testis","ntpm":155.1}],"url":"https://www.proteinatlas.org/search/TUBG1"},"hgnc":{"alias_symbol":["TUBGCP1"],"prev_symbol":["TUBG"]},"alphafold":{"accession":"P23258","domains":[{"cath_id":"3.40.50.1440","chopping":"3-261","consensus_level":"medium","plddt":94.037,"start":3,"end":261},{"cath_id":"3.30.1330.20","chopping":"271-383","consensus_level":"medium","plddt":85.9228,"start":271,"end":383},{"cath_id":"1.10.287.600","chopping":"386-444","consensus_level":"medium","plddt":95.9249,"start":386,"end":444}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P23258","model_url":"https://alphafold.ebi.ac.uk/files/AF-P23258-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P23258-F1-predicted_aligned_error_v6.png","plddt_mean":91.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TUBG1","jax_strain_url":"https://www.jax.org/strain/search?query=TUBG1"},"sequence":{"accession":"P23258","fasta_url":"https://rest.uniprot.org/uniprotkb/P23258.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P23258/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P23258"}},"corpus_meta":[{"pmid":"23603762","id":"PMC_23603762","title":"Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly.","date":"2013","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23603762","citation_count":367,"is_preprint":false},{"pmid":"25830658","id":"PMC_25830658","title":"Assessing associations between the AURKA-HMMR-TPX2-TUBG1 functional module and breast cancer risk in BRCA1/2 mutation carriers.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25830658","citation_count":40,"is_preprint":false},{"pmid":"31086189","id":"PMC_31086189","title":"TUBG1 missense variants underlying cortical malformations disrupt neuronal locomotion and microtubule dynamics but not neurogenesis.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/31086189","citation_count":22,"is_preprint":false},{"pmid":"31151415","id":"PMC_31151415","title":"Case reports: novel TUBG1 mutations with milder neurodevelopmental presentations.","date":"2019","source":"BMC medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31151415","citation_count":13,"is_preprint":false},{"pmid":"33728335","id":"PMC_33728335","title":"A novel TUBG1 mutation with neurodevelopmental disorder caused by malformations of cortical development.","date":"2021","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/33728335","citation_count":10,"is_preprint":false},{"pmid":"37806848","id":"PMC_37806848","title":"TuBG1 promotes hepatocellular carcinoma via ATR/P53-apoptosis and cycling pathways.","date":"2023","source":"Hepatobiliary & pancreatic diseases international : HBPD INT","url":"https://pubmed.ncbi.nlm.nih.gov/37806848","citation_count":9,"is_preprint":false},{"pmid":"39215931","id":"PMC_39215931","title":"tubg1 Somatic Mutants Show Tubulinopathy-Associated Neurodevelopmental Phenotypes in a Zebrafish Model.","date":"2024","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/39215931","citation_count":5,"is_preprint":false},{"pmid":"36792863","id":"PMC_36792863","title":"Upregulation of TUBG1 expression promotes hepatocellular carcinoma development.","date":"2023","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36792863","citation_count":4,"is_preprint":false},{"pmid":"38912084","id":"PMC_38912084","title":"Gamma-Tubulin 1 (TUBG1) Mutation-Associated Lissencephaly and Microcephaly in an Indian Child: A Rare Case.","date":"2024","source":"Cureus","url":"https://pubmed.ncbi.nlm.nih.gov/38912084","citation_count":4,"is_preprint":false},{"pmid":"38919239","id":"PMC_38919239","title":"Craniosynostosis Associated With Novel TUBG1 Mutation (NM_001070.4:c.821C>T) (p.Thr274Ile).","date":"2024","source":"Cureus","url":"https://pubmed.ncbi.nlm.nih.gov/38919239","citation_count":2,"is_preprint":false},{"pmid":"37685969","id":"PMC_37685969","title":"Centrosome Movements Are TUBG1-Dependent.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37685969","citation_count":1,"is_preprint":false},{"pmid":"40298439","id":"PMC_40298439","title":"Two New Cases Expand the Phenotypic Spectrum of TUBG1 Missense Variants.","date":"2025","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/40298439","citation_count":1,"is_preprint":false},{"pmid":"40013266","id":"PMC_40013266","title":"Molecular characterization of the TUBG1 meshwork's influence on Cytoskeletal organization.","date":"2025","source":"Heliyon","url":"https://pubmed.ncbi.nlm.nih.gov/40013266","citation_count":1,"is_preprint":false},{"pmid":"40019206","id":"PMC_40019206","title":"Targeting TUBG1 in RB1-negative tumors.","date":"2025","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/40019206","citation_count":0,"is_preprint":false},{"pmid":"37475831","id":"PMC_37475831","title":"Retracted: A novel TUBG1 mutation with neurodevelopmental disorder caused by malformations of cortical development.","date":"2023","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/37475831","citation_count":0,"is_preprint":false},{"pmid":"41070651","id":"PMC_41070651","title":"[Clinical phenotype and genetic analysis of a child with Cortical dysplasia, complex, with other brain malformations 4 and epilepsy due to a TUBG1 gene variant].","date":"2025","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41070651","citation_count":0,"is_preprint":false},{"pmid":"42177523","id":"PMC_42177523","title":"Gene-specific long-term course, neurodevelopmental outcome and quality of life in patients with LIS1/PAFAH1B1-, DCX-, DYNC1H1-, TUBA1A- and TUBG1-related lissencephaly.","date":"2026","source":"Orphanet journal of rare diseases","url":"https://pubmed.ncbi.nlm.nih.gov/42177523","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.03.11.25323037","title":"The First Report of a Homozygous<i>TUBG1</i>Splice Variant: Expanding the Genetic Spectrum of Tubulinopathies and Confirming the Dominant-Negative Effect","date":"2025-03-13","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.11.25323037","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10306,"output_tokens":2037,"usd":0.030736,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9056,"output_tokens":2639,"usd":0.055628,"stage2_stop_reason":"end_turn"},"total_usd":0.086364,"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\": 2013,\n      \"finding\": \"Suppression of mouse Tubg1 expression in vivo (in utero) interferes with proper neuronal migration, establishing a role for γ-tubulin in postmitotic neuronal positioning during cortical development. Additionally, expression of pathogenic TUBG1 missense variants in Saccharomyces cerevisiae disrupts normal microtubule behavior, indicating the mutations act on microtubule dynamics.\",\n      \"method\": \"In vivo mouse Tubg1 knockdown (shRNA), yeast microtubule behavior assay with mutant γ-tubulin expression\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo loss-of-function with specific neuronal migration phenotype replicated in two model organisms, published in high-impact journal\",\n      \"pmids\": [\"23603762\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Pathogenic TUBG1 missense variants (including Y92C) disrupt neuronal locomotion (postmitotic neuronal migration) and reduce microtubule dynamics in subject-derived fibroblasts without causing major structural or functional centrosome defects. Centrosomal positioning in bipolar neurons is correct but neurons fail to initiate locomotion. A knock-in Tubg1Y92C/+ mouse model recapitulates neuroanatomical and behavioral defects and increased epileptic cortical activity.\",\n      \"method\": \"In utero electroporation, knock-in mouse model (Tubg1Y92C/+), live-cell microtubule dynamics assay in patient-derived fibroblasts, behavioral and EEG phenotyping\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (in vivo electroporation, knock-in mouse, patient fibroblast microtubule dynamics), single lab with rigorous controls\",\n      \"pmids\": [\"31086189\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"TUBG1 forms a meshwork structure in mammalian cells; centrosome movements occur preferentially in cellular sites rich in GTPase TUBG1, and sgRNA-mediated reduction of TUBG1 expression alters the motility pattern of centrosomes, indicating the TUBG1 meshwork provides an interacting platform that mediates centrosome positional changes.\",\n      \"method\": \"Live-cell imaging with GFP-tagged TUBG1 and mRFP-tagged centrin 2, sgRNA-mediated TUBG1 knockdown, centrosome tracking\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct live-imaging localization tied to functional centrosome motility consequence, single lab, two orthogonal approaches (imaging + genetic knockdown)\",\n      \"pmids\": [\"37685969\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TUBG1 depletion via sgRNA disrupts microtubule, vimentin, and lamin B networks while reinforcing actin filament structures. Expression of N-terminal (TUBG1-335) or C-terminal (TUBG334-451) fragments of TUBG1 partially restores these networks, with the C-terminal fragment more effective at reestablishing microtubule integrity and both fragments stabilizing vimentin filaments and the nuclear envelope, demonstrating dual structural and regulatory roles for TUBG1 across multiple cytoskeletal systems.\",\n      \"method\": \"sgRNA-mediated TUBG1 knockdown, expression of TUBG1 domain fragments, immunofluorescence of cytoskeletal components\",\n      \"journal\": \"Heliyon\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — loss-of-function with defined cytoskeletal phenotype and domain-mapping rescue, single lab, multiple cytoskeletal readouts\",\n      \"pmids\": [\"40013266\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Somatic tubg1 mutation in zebrafish disrupts neurogenesis and brain development, mirroring microcephaly phenotypes, and γ-tubulin deficiency impairs canonical Wnt/β-catenin signaling activity, suggesting a regulatory link between γ-tubulin and Wnt signaling in brain development.\",\n      \"method\": \"Zebrafish somatic CRISPR/Cas9 tubg1 mutant model, Wnt/β-catenin reporter assay, neurogenesis and brain morphology analysis\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — in vivo loss-of-function with defined phenotype and Wnt pathway readout, single lab, two orthogonal phenotypic assessments\",\n      \"pmids\": [\"39215931\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TUBG1 operates in an E2F1-RB1 network; a small-molecule inhibitor (L12) targeting TUBG1 (but not TUBG2) enhances RB1 expression and selectively kills RB1-deficient tumor cells via E2F1-mediated upregulation of procaspase 3 and subsequent apoptosis. L12 cytotoxicity is attenuated by reduced E2F1 expression and demonstrates antitumor efficacy in xenografted small cell lung cancer models.\",\n      \"method\": \"Small-molecule TUBG1 inhibitor treatment, RB1/E2F1/procaspase-3 Western blotting, E2F1 knockdown rescue experiment, xenograft tumor model\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis (E2F1 knockdown rescue) combined with in vivo xenograft and pathway-level mechanistic readouts, single lab\",\n      \"pmids\": [\"40019206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Silencing TUBG1 in hepatocellular carcinoma cell lines increases G1 arrest, inhibits proliferation and invasion, promotes apoptosis, and upregulates ATR, P-P38MAPK, P-P53, Bax, cleaved caspase 3, and P21 while downregulating Bcl-2, cyclin D1, cyclin E2, CDK2, and CDK4, placing TUBG1 upstream of the ATR/P53 apoptosis and cyclin-CDK cell cycle pathways.\",\n      \"method\": \"siRNA-mediated TUBG1 silencing in HCC cell lines, flow cytometry, colony formation, Western blotting of pathway components\",\n      \"journal\": \"Hepatobiliary & pancreatic diseases international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — loss-of-function with multiple downstream pathway readouts, single lab, several orthogonal assays\",\n      \"pmids\": [\"37806848\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TUBG1 encodes γ-tubulin, a GTPase component of the γ-tubulin ring complex (γ-TuRC) that nucleates microtubules at the centrosome/MTOC; pathogenic missense variants reduce microtubule dynamics and impair postmitotic neuronal locomotion during cortical development without disrupting centrosome structure, the TUBG1 meshwork provides a platform for centrosome motility, and TUBG1 also coordinates a broader cytoskeletal network (microtubules, vimentin, lamin B) and participates in an E2F1-RB1 cell-cycle/apoptosis network in tumor cells.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TUBG1 encodes γ-tubulin, a GTPase that organizes microtubule architecture and is essential for postmitotic neuronal positioning during cortical development [#0]. Pathogenic missense variants, including Y92C, reduce microtubule dynamics and impair neuronal locomotion—bipolar neurons position their centrosomes correctly but fail to initiate migration—without producing major structural centrosome defects, and a knock-in mouse recapitulates the neuroanatomical, behavioral, and epileptic phenotypes, establishing TUBG1 as a cause of cortical malformation [#1]. In mammalian cells TUBG1 assembles into a meshwork that serves as an interacting platform directing centrosome motility [#2], and its activity extends beyond microtubules to maintain vimentin and lamin B networks while restraining actin, with N- and C-terminal fragments separably restoring these systems [#3]. In disease contexts, γ-tubulin loss impairs canonical Wnt/β-catenin signaling during brain development [#4] and operates within an E2F1–RB1 axis: pharmacological TUBG1 inhibition elevates RB1, drives E2F1-mediated procaspase-3 upregulation, and selectively kills RB1-deficient tumor cells [#5], consistent with TUBG1 silencing triggering G1 arrest and ATR/P53-dependent apoptosis in carcinoma cells [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established that γ-tubulin is required not only for cell division but specifically for postmitotic neuronal migration in the developing cortex, and that disease variants act through microtubule dynamics.\",\n      \"evidence\": \"In vivo mouse Tubg1 knockdown (shRNA) plus mutant γ-tubulin expression in yeast microtubule assay\",\n      \"pmids\": [\"23603762\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve whether the migration defect reflects loss of nucleation versus altered dynamics\", \"No structural mapping of variant effects\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined the cellular defect underlying TUBG1-linked malformation: reduced microtubule dynamics impair locomotion initiation despite correct centrosome positioning and intact centrosome function.\",\n      \"evidence\": \"In utero electroporation, Tubg1Y92C/+ knock-in mouse, live microtubule dynamics in patient fibroblasts, EEG/behavioral phenotyping\",\n      \"pmids\": [\"31086189\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking reduced dynamics to locomotion failure not resolved\", \"Centrosome-independent function only inferred, not directly assayed at molecular level\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showed TUBG1 forms a cellular meshwork that functions as a positional platform for centrosome movement, extending its role beyond a punctate nucleation site.\",\n      \"evidence\": \"Live-cell imaging of GFP-TUBG1 and mRFP-centrin 2 with sgRNA knockdown and centrosome tracking\",\n      \"pmids\": [\"37685969\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular composition of the meshwork not defined\", \"Single lab, two approaches\", \"How the meshwork mechanically couples to centrosomes unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Placed TUBG1 upstream of cell-cycle and apoptosis control in carcinoma cells, linking its loss to G1 arrest via cyclin-CDK suppression and ATR/P53-dependent apoptosis.\",\n      \"evidence\": \"siRNA silencing in HCC cell lines with flow cytometry, colony formation, and Western blot of pathway components\",\n      \"pmids\": [\"37806848\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Correlative pathway readouts without direct epistasis\", \"Single lab\", \"Whether effects are direct or secondary to mitotic disruption unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected γ-tubulin to a signaling pathway, showing its deficiency impairs canonical Wnt/β-catenin activity during brain development and microcephaly phenotypes.\",\n      \"evidence\": \"Zebrafish somatic CRISPR/Cas9 tubg1 mutant with Wnt/β-catenin reporter and neurogenesis analysis\",\n      \"pmids\": [\"39215931\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between γ-tubulin and Wnt signaling not defined\", \"Whether Wnt effect is cytoskeleton-dependent unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated paralog-selective druggability of TUBG1 within an E2F1-RB1 network, enabling selective killing of RB1-deficient tumors via procaspase-3 upregulation.\",\n      \"evidence\": \"Small-molecule TUBG1 inhibitor (L12), RB1/E2F1/procaspase-3 Western blot, E2F1 knockdown rescue, SCLC xenograft\",\n      \"pmids\": [\"40019206\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct target engagement of L12 with TUBG1 not structurally confirmed\", \"Mechanism by which TUBG1 inhibition elevates RB1 unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Broadened TUBG1's structural role beyond microtubules, showing it coordinates vimentin and lamin B networks and that distinct termini carry separable structural functions.\",\n      \"evidence\": \"sgRNA knockdown with N- and C-terminal fragment rescue and immunofluorescence of cytoskeletal components\",\n      \"pmids\": [\"40013266\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding to vimentin/lamin B not demonstrated\", \"Single lab\", \"Whether intermediate-filament effects are direct or secondary to microtubule loss unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular mechanism by which γ-tubulin coordinates multiple cytoskeletal systems and intersects Wnt and E2F1-RB1 signaling remains undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the TUBG1 meshwork\", \"Direct partners outside the microtubule system not identified\", \"Causal link between cytoskeletal and signaling roles unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 1, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1, 4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}