{"gene":"MNAT1","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":1998,"finding":"MNAT1 (MAT1) functions as an assembly factor for the CDK-activating kinase (CAK) complex, which contains CDK7, cyclin H, and MAT1; this trimeric complex is tightly associated with the multiprotein TFIIH complex that plays dual roles in transcription and DNA repair. The human MNAT1 gene was mapped to chromosome band 14q23 by FISH, somatic cell hybrid analysis, and YAC contig mapping.","method":"Fluorescence in situ hybridization, somatic cell hybrid analysis, YAC contig mapping; complex composition referenced from biochemical literature","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — chromosomal mapping is direct experimental work; CAK complex composition is well-established context cited in the paper, single lab for the mapping data","pmids":["9465303"],"is_preprint":false},{"year":2018,"finding":"MNAT1 physically interacts with p53 (shown by co-immunoprecipitation), enhances the interaction of MDM2 with p53, mediates p53 ubiquitin-dependent degradation, shortens p53 half-life, and reduces p53 protein stability, thereby promoting colorectal cancer cell growth and inhibiting apoptosis.","method":"Co-immunoprecipitation, Western blot (p53 stability/half-life), flow cytometry (apoptosis), MTT/colony formation, in vivo xenograft","journal":"Journal of experimental & clinical cancer research : CR","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP plus half-life assay plus in vivo validation, single lab but multiple orthogonal methods","pmids":["30477538"],"is_preprint":false},{"year":2020,"finding":"MNAT1 silencing in osteosarcoma cells reduces activation of the PI3K/Akt/mTOR pathway, and this pathway mediates MNAT1's promotion of OS cell proliferation and cisplatin resistance.","method":"siRNA knockdown, Western blot (PI3K/Akt/mTOR effectors), CCK8/colony formation assay, transwell assay, in vivo xenograft","journal":"BMC cancer","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pathway placement based on downstream effector blotting without direct reconstitution or rescue","pmids":["33272245"],"is_preprint":false},{"year":2020,"finding":"Decreased mNAT1 expression in cerebral endothelial cells induces lysosomal degradation of A20 (a necroptosis regulator) and LRP1β (a component of the LRP1 complex that exports Aβ), leading to blood-brain barrier damage and endothelial necroptosis; AAV-mediated restoration of mNAT1 in cerebral ECs rescues A20 and LRP1β levels, inhibits necroptosis, reduces Aβ deposits, and improves cognitive function.","method":"Nat1-/- mice, AD mouse models, AAV-mediated rescue, Western blot, behavioral assays, BBB permeability assays","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout plus AAV rescue with multiple orthogonal readouts in a single lab","pmids":["33296651"],"is_preprint":false},{"year":2023,"finding":"SMYD2 methyltransferase catalyzes H3K36me2 modification at the MNAT1 promoter to upregulate MNAT1 transcription; elevated MNAT1 in turn activates PI3K/AKT signaling to promote pancreatic adenocarcinoma tumorigenesis, and MNAT1 overexpression rescues the suppressed malignant phenotype caused by SMYD2 knockdown.","method":"Chromatin immunoprecipitation (H3K36me2 at MNAT1 promoter), luciferase reporter assay, siRNA/overexpression, Western blot (PI3K/AKT effectors), in vivo xenograft","journal":"Histology and histopathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and luciferase reporter directly establish epigenetic regulation; rescue experiment confirms epistasis; single lab","pmids":["37232506"],"is_preprint":false},{"year":2025,"finding":"MNAT1 physically interacts with GDF15 (by co-immunoprecipitation); MNAT1 promotes LSCC cell proliferation, migration, and invasion through GDF15, and further affects mitochondrial apoptosis via the AMPK pathway. MNAT1 knockdown increases cisplatin sensitivity both in vitro and in vivo.","method":"Co-immunoprecipitation, RNA-seq (downstream gene prediction), ROS/JC-1/lysosomal-mitochondrial activity assays, in vivo xenograft with cisplatin","journal":"Translational oncology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, co-IP establishes interaction, but AMPK pathway placement relies on downstream readouts without direct reconstitution","pmids":["40651179"],"is_preprint":false},{"year":2025,"finding":"TDP-43 dysfunction leads to inclusion of a novel cryptic exon in MNAT1 pre-mRNA in human iPSC-derived motor neurons, generating aberrant MNAT1 transcripts; this cryptic exon is detectable in ALS and FTD patient samples, implicating MNAT1 splicing disruption in TDP-43 proteinopathy.","method":"Long-read RNA-seq (IsoRefiner method), short-read RNA-seq, validation in patient samples (ALS/FTD)","journal":"Communications biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — identifies a splicing event but does not establish the functional consequence of the aberrant MNAT1 isoform; single lab","pmids":["40670663"],"is_preprint":false}],"current_model":"MNAT1 (MAT1) is an assembly factor for the trimeric CDK7–cyclin H–MAT1 CAK complex (which activates cyclin-bound CDKs and associates with TFIIH for transcription/DNA repair); in cancer cells it physically binds p53 and facilitates MDM2-mediated ubiquitin degradation of p53 to suppress apoptosis, and it drives PI3K/AKT/mTOR signaling; in cerebral endothelial cells it stabilizes A20 and LRP1β against lysosomal degradation to prevent necroptosis and maintain Aβ clearance; its transcription is epigenetically activated by SMYD2-mediated H3K36me2 at its promoter; and TDP-43 dysfunction generates aberrant MNAT1 splice isoforms containing a cryptic exon."},"narrative":{"mechanistic_narrative":"MNAT1 (MAT1) is an assembly factor for the trimeric CDK-activating kinase (CAK) complex containing CDK7 and cyclin H, which associates with the TFIIH complex that operates in both transcription and DNA repair [PMID:9465303]. Beyond this core role, MNAT1 has been characterized predominantly as a pro-tumorigenic regulator: it physically binds p53, enhances MDM2–p53 association, and promotes ubiquitin-dependent p53 degradation, thereby shortening p53 half-life and suppressing apoptosis to drive colorectal cancer growth [PMID:30477538]. In cerebral endothelial cells, MNAT1 has a protective function, stabilizing the necroptosis regulator A20 and the Aβ-export component LRP1β against lysosomal degradation, so that its loss provokes blood–brain barrier damage, necroptosis, and Aβ accumulation [PMID:33296651]. Its own transcription is epigenetically activated by SMYD2-catalyzed H3K36me2 deposition at the MNAT1 promoter [PMID:37232506].","teleology":[{"year":1998,"claim":"Established MNAT1 as the assembly-factor subunit (MAT1) of the CDK7–cyclin H CAK complex and placed the gene at chromosome 14q23, anchoring its identity in the transcription/DNA-repair machinery via TFIIH.","evidence":"FISH, somatic cell hybrid analysis, and YAC contig mapping; CAK composition from biochemical literature","pmids":["9465303"],"confidence":"Medium","gaps":["Does not provide functional dissection of MNAT1's role within CAK beyond cited context","No structural basis for assembly defined here"]},{"year":2018,"claim":"Answered how MNAT1 promotes cancer cell survival by showing it physically binds p53 and accelerates its MDM2-dependent degradation, linking MNAT1 to apoptosis suppression independent of its canonical CAK role.","evidence":"Co-immunoprecipitation, p53 half-life Western blot, apoptosis flow cytometry, colony formation, and xenograft in colorectal cancer cells","pmids":["30477538"],"confidence":"Medium","gaps":["Mechanism by which MNAT1 enhances MDM2–p53 binding not structurally resolved","Relationship to CAK/TFIIH function unaddressed"]},{"year":2020,"claim":"Extended MNAT1's oncogenic role to PI3K/Akt/mTOR signaling, indicating it promotes proliferation and chemoresistance through a growth-signaling axis.","evidence":"siRNA knockdown, effector Western blots, proliferation/invasion assays, and xenograft in osteosarcoma cells","pmids":["33272245"],"confidence":"Low","gaps":["Pathway placement rests on downstream effector blotting without reconstitution or rescue","Direct molecular link between MNAT1 and PI3K not established"]},{"year":2020,"claim":"Revealed a protective, tissue-specific function distinct from cancer contexts: MNAT1 stabilizes A20 and LRP1β against lysosomal degradation in cerebral endothelium to prevent necroptosis and maintain Aβ clearance.","evidence":"Nat1-/- mice, AD models, AAV-mediated rescue, Western blot, BBB permeability and behavioral assays","pmids":["33296651"],"confidence":"Medium","gaps":["Molecular mechanism by which MNAT1 prevents lysosomal degradation of A20/LRP1β not defined","Whether this requires CAK assembly activity unknown"]},{"year":2023,"claim":"Identified an upstream regulator of MNAT1 expression, showing SMYD2-catalyzed H3K36me2 at the promoter drives MNAT1 transcription, with MNAT1 acting downstream to activate PI3K/AKT in pancreatic cancer.","evidence":"ChIP for H3K36me2, luciferase reporter, knockdown/overexpression rescue, effector Western blots, and xenograft","pmids":["37232506"],"confidence":"Medium","gaps":["Direct MNAT1–PI3K mechanistic link still inferred from effector readouts","Generality of SMYD2 regulation across tissues untested"]},{"year":2025,"claim":"Proposed a further oncogenic effector arm in which MNAT1 binds GDF15 and modulates mitochondrial apoptosis via AMPK signaling.","evidence":"Co-immunoprecipitation, RNA-seq, ROS/JC-1/mitochondrial assays, and cisplatin xenograft in laryngeal squamous cell carcinoma","pmids":["40651179"],"confidence":"Low","gaps":["AMPK pathway placement relies on downstream readouts without reconstitution","GDF15 interaction lacks reciprocal/structural validation"]},{"year":2025,"claim":"Linked MNAT1 to TDP-43 proteinopathy by showing TDP-43 dysfunction generates a cryptic-exon-containing aberrant MNAT1 transcript detectable in ALS/FTD patients.","evidence":"Long- and short-read RNA-seq in iPSC-derived motor neurons with patient-sample validation","pmids":["40670663"],"confidence":"Low","gaps":["Functional consequence of the aberrant MNAT1 isoform not established","Whether mis-splicing alters MNAT1 protein activity unknown"]},{"year":null,"claim":"How MNAT1's canonical CAK/TFIIH assembly role mechanistically connects to its diverse context-specific functions (p53 degradation, protein stabilization, growth signaling) remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model linking CAK assembly to non-canonical partner binding","Whether CAK kinase activity is required for cancer or endothelial roles untested","Mechanism of MNAT1-dependent control of protein stability undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,3]}],"localization":[],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[0]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,4]}],"complexes":["CDK7–cyclin H–MAT1 CAK complex","TFIIH"],"partners":["CDK7","CYCLIN H","P53","MDM2","A20","LRP1","GDF15"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P51948","full_name":"CDK-activating kinase assembly factor MAT1","aliases":["CDK7/cyclin-H assembly factor","Cyclin-G1-interacting protein","Menage a trois","RING finger protein 66","RING finger protein MAT1","p35","p36"],"length_aa":309,"mass_kda":35.8,"function":"Stabilizes the cyclin H-CDK7 complex to form a functional CDK-activating kinase (CAK) enzymatic complex. CAK activates the cyclin-associated kinases CDK1, CDK2, CDK4 and CDK6 by threonine phosphorylation. CAK complexed to the core-TFIIH basal transcription factor activates RNA polymerase II by serine phosphorylation of the repetitive C-terminal domain (CTD) of its large subunit (POLR2A), allowing its escape from the promoter and elongation of the transcripts. Involved in cell cycle control and in RNA transcription by RNA polymerase II","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/P51948/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/MNAT1","classification":"Common Essential","n_dependent_lines":1053,"n_total_lines":1208,"dependency_fraction":0.8716887417218543},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CDC7","stoichiometry":10.0},{"gene":"CDK7","stoichiometry":10.0},{"gene":"CETN2","stoichiometry":0.2},{"gene":"HIST2H2BE","stoichiometry":0.2},{"gene":"KPNA4","stoichiometry":0.2},{"gene":"POLR2K","stoichiometry":0.2},{"gene":"SSRP1","stoichiometry":0.2},{"gene":"TBP","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MNAT1","total_profiled":1310},"omim":[{"mim_id":"608000","title":"N-ALPHA-ACETYLTRANSFERASE 15, NatA AUXILIARY SUBUNIT; NAA15","url":"https://www.omim.org/entry/608000"},{"mim_id":"602659","title":"MENAGE A TROIS 1; MNAT1","url":"https://www.omim.org/entry/602659"},{"mim_id":"601953","title":"CYCLIN H; CCNH","url":"https://www.omim.org/entry/601953"},{"mim_id":"126340","title":"ERCC EXCISION REPAIR 2, TFIIH CORE COMPLEX HELICASE SUBUNIT; ERCC2","url":"https://www.omim.org/entry/126340"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MNAT1"},"hgnc":{"alias_symbol":["MAT1","RNF66"],"prev_symbol":[]},"alphafold":{"accession":"P51948","domains":[{"cath_id":"3.30.40.10","chopping":"1-61","consensus_level":"medium","plddt":87.3228,"start":1,"end":61},{"cath_id":"1.20.1440","chopping":"76-141","consensus_level":"medium","plddt":91.0438,"start":76,"end":141},{"cath_id":"1.20.5","chopping":"142-211","consensus_level":"medium","plddt":88.0819,"start":142,"end":211}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P51948","model_url":"https://alphafold.ebi.ac.uk/files/AF-P51948-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P51948-F1-predicted_aligned_error_v6.png","plddt_mean":85.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MNAT1","jax_strain_url":"https://www.jax.org/strain/search?query=MNAT1"},"sequence":{"accession":"P51948","fasta_url":"https://rest.uniprot.org/uniprotkb/P51948.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P51948/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P51948"}},"corpus_meta":[{"pmid":"33296651","id":"PMC_33296651","title":"Reduction of mNAT1/hNAT2 Contributes to Cerebral Endothelial Necroptosis and Aβ Accumulation in Alzheimer's Disease.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/33296651","citation_count":44,"is_preprint":false},{"pmid":"33272245","id":"PMC_33272245","title":"MNAT1 promotes proliferation and the chemo-resistance of osteosarcoma cell to cisplatin through regulating PI3K/Akt/mTOR pathway.","date":"2020","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/33272245","citation_count":21,"is_preprint":false},{"pmid":"32453410","id":"PMC_32453410","title":"The regulatory effect of has-circ-0001146/miR-26a-5p/MNAT1 network on the proliferation and invasion of osteosarcoma.","date":"2020","source":"Bioscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/32453410","citation_count":12,"is_preprint":false},{"pmid":"30477538","id":"PMC_30477538","title":"MNAT1 is overexpressed in colorectal cancer and mediates p53 ubiquitin-degradation to promote colorectal cancer malignance.","date":"2018","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/30477538","citation_count":11,"is_preprint":false},{"pmid":"37232506","id":"PMC_37232506","title":"Epigenetic upregulation of MNAT1 by SMYD2 is linked to PI3K/AKT activation and tumorigenesis of pancreatic adenocarcinoma.","date":"2023","source":"Histology and histopathology","url":"https://pubmed.ncbi.nlm.nih.gov/37232506","citation_count":7,"is_preprint":false},{"pmid":"9465303","id":"PMC_9465303","title":"Mapping of the human genes encoding cyclin H (CCNH) and the CDK-activating kinase (CAK) assembly factor MAT1 (MNAT1) to chromosome bands 5q13.3-q14 and 14q23, respectively.","date":"1998","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/9465303","citation_count":6,"is_preprint":false},{"pmid":"24664931","id":"PMC_24664931","title":"An intragenic deletion of the gene MNAT1 in a family with pectus deformities.","date":"2014","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/24664931","citation_count":4,"is_preprint":false},{"pmid":"40670663","id":"PMC_40670663","title":"Long-read RNA sequencing unveils a novel cryptic exon in MNAT1 along with its full-length transcript structure in TDP-43 proteinopathy.","date":"2025","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/40670663","citation_count":3,"is_preprint":false},{"pmid":"31422594","id":"PMC_31422594","title":"[MNAT1 expression in non-small cell lung cancer and its biological cellular impact].","date":"2019","source":"Zhonghua bing li xue za zhi = Chinese journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/31422594","citation_count":2,"is_preprint":false},{"pmid":"41235252","id":"PMC_41235252","title":"Integrating scRNA-seq and machine learning identifies MNAT1 as a therapeutic target in OSCC.","date":"2025","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41235252","citation_count":0,"is_preprint":false},{"pmid":"40651179","id":"PMC_40651179","title":"Mitochondrial apoptosis induced by MNAT1 in laryngeal squamous cell carcinoma cells reverses drug resistance.","date":"2025","source":"Translational oncology","url":"https://pubmed.ncbi.nlm.nih.gov/40651179","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7768,"output_tokens":1940,"usd":0.026202,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8879,"output_tokens":2603,"usd":0.054735,"stage2_stop_reason":"end_turn"},"total_usd":0.080937,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"MNAT1 (MAT1) functions as an assembly factor for the CDK-activating kinase (CAK) complex, which contains CDK7, cyclin H, and MAT1; this trimeric complex is tightly associated with the multiprotein TFIIH complex that plays dual roles in transcription and DNA repair. The human MNAT1 gene was mapped to chromosome band 14q23 by FISH, somatic cell hybrid analysis, and YAC contig mapping.\",\n      \"method\": \"Fluorescence in situ hybridization, somatic cell hybrid analysis, YAC contig mapping; complex composition referenced from biochemical literature\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — chromosomal mapping is direct experimental work; CAK complex composition is well-established context cited in the paper, single lab for the mapping data\",\n      \"pmids\": [\"9465303\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MNAT1 physically interacts with p53 (shown by co-immunoprecipitation), enhances the interaction of MDM2 with p53, mediates p53 ubiquitin-dependent degradation, shortens p53 half-life, and reduces p53 protein stability, thereby promoting colorectal cancer cell growth and inhibiting apoptosis.\",\n      \"method\": \"Co-immunoprecipitation, Western blot (p53 stability/half-life), flow cytometry (apoptosis), MTT/colony formation, in vivo xenograft\",\n      \"journal\": \"Journal of experimental & clinical cancer research : CR\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP plus half-life assay plus in vivo validation, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"30477538\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"MNAT1 silencing in osteosarcoma cells reduces activation of the PI3K/Akt/mTOR pathway, and this pathway mediates MNAT1's promotion of OS cell proliferation and cisplatin resistance.\",\n      \"method\": \"siRNA knockdown, Western blot (PI3K/Akt/mTOR effectors), CCK8/colony formation assay, transwell assay, in vivo xenograft\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pathway placement based on downstream effector blotting without direct reconstitution or rescue\",\n      \"pmids\": [\"33272245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Decreased mNAT1 expression in cerebral endothelial cells induces lysosomal degradation of A20 (a necroptosis regulator) and LRP1β (a component of the LRP1 complex that exports Aβ), leading to blood-brain barrier damage and endothelial necroptosis; AAV-mediated restoration of mNAT1 in cerebral ECs rescues A20 and LRP1β levels, inhibits necroptosis, reduces Aβ deposits, and improves cognitive function.\",\n      \"method\": \"Nat1-/- mice, AD mouse models, AAV-mediated rescue, Western blot, behavioral assays, BBB permeability assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout plus AAV rescue with multiple orthogonal readouts in a single lab\",\n      \"pmids\": [\"33296651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SMYD2 methyltransferase catalyzes H3K36me2 modification at the MNAT1 promoter to upregulate MNAT1 transcription; elevated MNAT1 in turn activates PI3K/AKT signaling to promote pancreatic adenocarcinoma tumorigenesis, and MNAT1 overexpression rescues the suppressed malignant phenotype caused by SMYD2 knockdown.\",\n      \"method\": \"Chromatin immunoprecipitation (H3K36me2 at MNAT1 promoter), luciferase reporter assay, siRNA/overexpression, Western blot (PI3K/AKT effectors), in vivo xenograft\",\n      \"journal\": \"Histology and histopathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and luciferase reporter directly establish epigenetic regulation; rescue experiment confirms epistasis; single lab\",\n      \"pmids\": [\"37232506\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MNAT1 physically interacts with GDF15 (by co-immunoprecipitation); MNAT1 promotes LSCC cell proliferation, migration, and invasion through GDF15, and further affects mitochondrial apoptosis via the AMPK pathway. MNAT1 knockdown increases cisplatin sensitivity both in vitro and in vivo.\",\n      \"method\": \"Co-immunoprecipitation, RNA-seq (downstream gene prediction), ROS/JC-1/lysosomal-mitochondrial activity assays, in vivo xenograft with cisplatin\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, co-IP establishes interaction, but AMPK pathway placement relies on downstream readouts without direct reconstitution\",\n      \"pmids\": [\"40651179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TDP-43 dysfunction leads to inclusion of a novel cryptic exon in MNAT1 pre-mRNA in human iPSC-derived motor neurons, generating aberrant MNAT1 transcripts; this cryptic exon is detectable in ALS and FTD patient samples, implicating MNAT1 splicing disruption in TDP-43 proteinopathy.\",\n      \"method\": \"Long-read RNA-seq (IsoRefiner method), short-read RNA-seq, validation in patient samples (ALS/FTD)\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — identifies a splicing event but does not establish the functional consequence of the aberrant MNAT1 isoform; single lab\",\n      \"pmids\": [\"40670663\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MNAT1 (MAT1) is an assembly factor for the trimeric CDK7–cyclin H–MAT1 CAK complex (which activates cyclin-bound CDKs and associates with TFIIH for transcription/DNA repair); in cancer cells it physically binds p53 and facilitates MDM2-mediated ubiquitin degradation of p53 to suppress apoptosis, and it drives PI3K/AKT/mTOR signaling; in cerebral endothelial cells it stabilizes A20 and LRP1β against lysosomal degradation to prevent necroptosis and maintain Aβ clearance; its transcription is epigenetically activated by SMYD2-mediated H3K36me2 at its promoter; and TDP-43 dysfunction generates aberrant MNAT1 splice isoforms containing a cryptic exon.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MNAT1 (MAT1) is an assembly factor for the trimeric CDK-activating kinase (CAK) complex containing CDK7 and cyclin H, which associates with the TFIIH complex that operates in both transcription and DNA repair [#0]. Beyond this core role, MNAT1 has been characterized predominantly as a pro-tumorigenic regulator: it physically binds p53, enhances MDM2–p53 association, and promotes ubiquitin-dependent p53 degradation, thereby shortening p53 half-life and suppressing apoptosis to drive colorectal cancer growth [#1]. In cerebral endothelial cells, MNAT1 has a protective function, stabilizing the necroptosis regulator A20 and the Aβ-export component LRP1β against lysosomal degradation, so that its loss provokes blood–brain barrier damage, necroptosis, and Aβ accumulation [#3]. Its own transcription is epigenetically activated by SMYD2-catalyzed H3K36me2 deposition at the MNAT1 promoter [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established MNAT1 as the assembly-factor subunit (MAT1) of the CDK7–cyclin H CAK complex and placed the gene at chromosome 14q23, anchoring its identity in the transcription/DNA-repair machinery via TFIIH.\",\n      \"evidence\": \"FISH, somatic cell hybrid analysis, and YAC contig mapping; CAK composition from biochemical literature\",\n      \"pmids\": [\"9465303\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not provide functional dissection of MNAT1's role within CAK beyond cited context\", \"No structural basis for assembly defined here\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Answered how MNAT1 promotes cancer cell survival by showing it physically binds p53 and accelerates its MDM2-dependent degradation, linking MNAT1 to apoptosis suppression independent of its canonical CAK role.\",\n      \"evidence\": \"Co-immunoprecipitation, p53 half-life Western blot, apoptosis flow cytometry, colony formation, and xenograft in colorectal cancer cells\",\n      \"pmids\": [\"30477538\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which MNAT1 enhances MDM2–p53 binding not structurally resolved\", \"Relationship to CAK/TFIIH function unaddressed\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended MNAT1's oncogenic role to PI3K/Akt/mTOR signaling, indicating it promotes proliferation and chemoresistance through a growth-signaling axis.\",\n      \"evidence\": \"siRNA knockdown, effector Western blots, proliferation/invasion assays, and xenograft in osteosarcoma cells\",\n      \"pmids\": [\"33272245\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Pathway placement rests on downstream effector blotting without reconstitution or rescue\", \"Direct molecular link between MNAT1 and PI3K not established\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Revealed a protective, tissue-specific function distinct from cancer contexts: MNAT1 stabilizes A20 and LRP1β against lysosomal degradation in cerebral endothelium to prevent necroptosis and maintain Aβ clearance.\",\n      \"evidence\": \"Nat1-/- mice, AD models, AAV-mediated rescue, Western blot, BBB permeability and behavioral assays\",\n      \"pmids\": [\"33296651\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism by which MNAT1 prevents lysosomal degradation of A20/LRP1β not defined\", \"Whether this requires CAK assembly activity unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified an upstream regulator of MNAT1 expression, showing SMYD2-catalyzed H3K36me2 at the promoter drives MNAT1 transcription, with MNAT1 acting downstream to activate PI3K/AKT in pancreatic cancer.\",\n      \"evidence\": \"ChIP for H3K36me2, luciferase reporter, knockdown/overexpression rescue, effector Western blots, and xenograft\",\n      \"pmids\": [\"37232506\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct MNAT1–PI3K mechanistic link still inferred from effector readouts\", \"Generality of SMYD2 regulation across tissues untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed a further oncogenic effector arm in which MNAT1 binds GDF15 and modulates mitochondrial apoptosis via AMPK signaling.\",\n      \"evidence\": \"Co-immunoprecipitation, RNA-seq, ROS/JC-1/mitochondrial assays, and cisplatin xenograft in laryngeal squamous cell carcinoma\",\n      \"pmids\": [\"40651179\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"AMPK pathway placement relies on downstream readouts without reconstitution\", \"GDF15 interaction lacks reciprocal/structural validation\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked MNAT1 to TDP-43 proteinopathy by showing TDP-43 dysfunction generates a cryptic-exon-containing aberrant MNAT1 transcript detectable in ALS/FTD patients.\",\n      \"evidence\": \"Long- and short-read RNA-seq in iPSC-derived motor neurons with patient-sample validation\",\n      \"pmids\": [\"40670663\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Functional consequence of the aberrant MNAT1 isoform not established\", \"Whether mis-splicing alters MNAT1 protein activity unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MNAT1's canonical CAK/TFIIH assembly role mechanistically connects to its diverse context-specific functions (p53 degradation, protein stabilization, growth signaling) remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model linking CAK assembly to non-canonical partner binding\", \"Whether CAK kinase activity is required for cancer or endothelial roles untested\", \"Mechanism of MNAT1-dependent control of protein stability undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 3]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 4]}\n    ],\n    \"complexes\": [\"CDK7–cyclin H–MAT1 CAK complex\", \"TFIIH\"],\n    \"partners\": [\"CDK7\", \"cyclin H\", \"p53\", \"MDM2\", \"A20\", \"LRP1\", \"GDF15\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}