{"gene":"NTMT1","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2010,"finding":"NRMT1 (NRMT) is the first identified eukaryotic alpha-N-methyltransferase, catalyzing mono-, di-, and trimethylation of the free alpha-amino group of proteins bearing the N-terminal motif (Ala/Pro/Ser)-Pro-Lys (after Met cleavage). Substrates include RCC1 and retinoblastoma protein (RB). The NRMT recognition sequence was defined by substrate docking and mutational analysis of RCC1. Knockdown of NRMT recapitulates the multi-spindle phenotype seen with methylation-defective RCC1 mutants, establishing a role in bipolar spindle formation and chromosome segregation.","method":"In vitro methyltransferase assay, substrate docking, mutational analysis of RCC1, siRNA knockdown with mitotic phenotype readout, mass spectrometry","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro enzymatic reconstitution, mutagenesis, and functional KD phenotype; foundational discovery paper with multiple orthogonal methods","pmids":["20668449"],"is_preprint":false},{"year":2013,"finding":"NRMT1 is a distributive methyltransferase capable of mono-, di-, and trimethylation of N-terminal substrates, whereas its homolog NRMT2 is primarily a monomethylase recognizing the same consensus sequences. Concurrent expression of NRMT1 and NRMT2 accelerates production of trimethylation, with NRMT2 proposed to prime substrates for NRMT1-mediated trimethylation.","method":"In vitro enzyme assays, mass spectrometry, co-expression experiments","journal":"The Biochemical Journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzyme assays with MS validation, single lab but two orthogonal methods clearly distinguishing catalytic activities","pmids":["24090352"],"is_preprint":false},{"year":2017,"finding":"CENP-A undergoes alpha-amino trimethylation by NRMT1 in vivo. Loss of this trimethylation reduces CENP-T and CENP-I CCAN components at the centromere, causes lagging chromosomes and spindle pole defects, and reduces cell survival.","method":"In vivo trimethylation assay, NRMT knockdown/knockout, immunofluorescence at centromeres, chromosome segregation assays","journal":"Nature Communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function with defined cellular phenotype, substrate identification validated in vivo, multiple orthogonal readouts","pmids":["28266506"],"is_preprint":false},{"year":2015,"finding":"Complete loss of NRMT1 in knockout mice results in decreased body size, female-specific infertility, kyphosis, decreased mitochondrial function, and early-onset liver degeneration. NRMT1 knockout mouse embryonic fibroblasts show decreased capacity for handling oxidative damage, positioning NRMT1 as required for normal DNA repair and genome maintenance.","method":"Constitutive knockout mouse generation, phenotypic analysis, ROS measurement, fibroblast oxidative damage assays","journal":"Mechanisms of Ageing and Development","confidence":"High","confidence_rationale":"Tier 2 / Strong — constitutive KO mouse with multiple defined phenotypic readouts across tissues and cell types","pmids":["25843235"],"is_preprint":false},{"year":2015,"finding":"NRMT1 knockdown significantly enhances sensitivity of breast cancer cell lines to etoposide and gamma-irradiation, and increases proliferation, invasive potential, anchorage-independent growth, and xenograft tumor size, positioning NRMT1 as a tumor suppressor involved in DNA double-strand break repair.","method":"siRNA knockdown, DNA damage sensitivity assays (etoposide, gamma-irradiation), cell proliferation, invasion, soft agar, xenograft","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with multiple cellular phenotype readouts in a single lab, but no direct biochemical mechanism for DSB repair established","pmids":["25909287"],"is_preprint":false},{"year":2017,"finding":"Cancer-associated NRMT1 mutants N209I (endometrial cancer) and P211S (lung cancer), located in the peptide-binding channel, display decreased trimethylase activity and increased mono/dimethylase activity with slower trimethylation rates and requirement for higher substrate concentration, identifying the peptide-binding channel as a structural determinant of enzyme specificity distinct from active-site aromatic residues.","method":"Site-directed mutagenesis of active-site aromatic residues and cancer mutants, in vitro enzyme activity assays, expression in WT and NRMT1-null cells","journal":"Protein Science","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct mutagenesis with in vitro enzymatic activity characterization, single lab, multiple orthogonal assays","pmids":["28556566"],"is_preprint":false},{"year":2018,"finding":"NRMT1 primarily exists as a homodimer while NRMT2 exists as a monomer; when co-expressed they form a heterotrimer. NRMT2 increases NRMT1 stability (half-life) and substrate affinity, thereby activating NRMT1 trimethylation activity. The catalytic activity of NRMT2 is not required for this activation, supporting a stability/scaffold model rather than a priming model.","method":"Analytical ultracentrifugation, co-immunoprecipitation, molecular modeling, half-life assays, enzyme activity assays","journal":"Protein Science","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — AUC for complex stoichiometry, reciprocal Co-IP for in vivo binding, catalytic-dead mutant rescue experiment; single lab, multiple orthogonal methods","pmids":["30151928"],"is_preprint":false},{"year":2019,"finding":"Activity-based substrate profiling using Hey-SAM identified OLA1 (Obg-like ATPase 1) as a novel substrate of NTMT1 methylated in vivo; this was validated using NTMT1 knockout HEK293FT cells generated by CRISPR-Cas9.","method":"Activity-based chemoproteomic profiling with Hey-SAM, CRISPR-Cas9 knockout validation, MS","journal":"Chemical Science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — activity-based profiling plus KO cellular validation, single lab","pmids":["31857877"],"is_preprint":false},{"year":2020,"finding":"Crystal structure of NTMT1 co-crystallized with peptidomimetic inhibitor BM30 reveals that the compound is a competitive inhibitor to the peptide substrate and noncompetitive to SAM, binding in the peptide substrate binding site. BM30 shows >100-fold selectivity for NTMT1/2 over 41 other methyltransferases. A cell-permeable analogue DC432 decreases N-terminal methylation of RCC1 and SET in HCT116 cells.","method":"Cocrystallization/X-ray structure, biochemical IC50 assays, selectivity panel against 41 MTs, cellular N-terminal methylation assay","journal":"Journal of Medicinal Chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with bound inhibitor, biochemical mechanism of inhibition defined, cellular target engagement validated","pmids":["32689795"],"is_preprint":false},{"year":2021,"finding":"NRMT1 loss in knockout mice causes misregulation of RB phosphorylation and degradation, and de-repression of RB target genes involved in cell cycle as well as the apoptosis-promoting RB target Noxa, establishing that NRMT1 regulates RB transcriptional repression during neurogenesis to promote neural stem cell quiescence.","method":"Constitutive Nrmt1-/- mouse, Western blotting for RB phosphorylation/degradation, gene expression analysis of RB targets, immunofluorescence, behavioral assays","journal":"Cell Death & Disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse with defined pathway placement (NRMT1→RB phosphorylation/stability→target gene de-repression), single lab","pmids":["34711807"],"is_preprint":false},{"year":2021,"finding":"CREB1 is the major transcriptional activator of NRMT1; CREB1 binds the NRMT1 minimal promoter and drives its expression during recovery from serum starvation and muscle cell differentiation. Knockout of NRMT1 in C2C12 myoblasts abolishes Pax7 expression, prevents muscle differentiation, and causes transdifferentiation toward an osteoblast-like fate.","method":"Luciferase reporter assay, promoter binding assay, CRISPR/Cas9 knockout in C2C12 cells, alkaline phosphatase and collagen expression assays, serum starvation/differentiation experiments","journal":"Transcription","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — luciferase and binding assays for transcriptional mechanism, CRISPR KO for cellular phenotype, single lab, two orthogonal methods","pmids":["34403304"],"is_preprint":false},{"year":2021,"finding":"A bisubstrate NTMT1 inhibitor NAH-C3-GPKK also potently inhibits the methyltransferase complex HemK2-Trm112 (KMT9-Trm112), as revealed by chemoproteomic pulldown with a biotinylated probe analogue; this cross-reactivity defines a selectivity boundary for NTMT1 bisubstrate inhibitors.","method":"Chemoproteomic pulldown, biochemical inhibition assays, competitor displacement with NAH-C3-GPKK","journal":"ACS Chemical Biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — chemoproteomic method plus biochemical validation, single lab","pmids":["34192867"],"is_preprint":false},{"year":2024,"finding":"PAD1 (protein arginine deiminase 1) is a substrate of NTMT1; NTMT1-mediated Nα-methylation of PAD1 increases PAD1 protein half-life and modulates its protein-protein interactions in HEK293T cells without affecting PAD1 enzymatic activity or cellular localization.","method":"Biochemical methylation assay, cellular half-life assay, co-immunoprecipitation/proteomic interaction profiling in HEK293T cells with WT vs. non-methylatable PAD1","journal":"Journal of Proteome Research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical and cellular assays with multiple readouts, single lab","pmids":["39287128"],"is_preprint":false},{"year":2025,"finding":"In Nrmt1-/- mice, onset of neuronal apoptosis corresponds to increased cleavage of p35 into the CDK5 activator p25, which promotes neuroinflammation. Nrmt1-/- brains exhibit pro-inflammatory cytokine signaling, astrogliosis, complement activation, microgliosis, and compromised blood-brain barrier markers, with no compensatory anti-inflammatory response, linking NRMT1-dependent neurogenesis defects to progressive neuroinflammation and neurodegeneration.","method":"Constitutive Nrmt1-/- mouse, Western blotting for p35/p25, cytokine assays, immunofluorescence for glial markers, complement assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — KO mouse with pathway placement (NRMT1→p35/p25 cleavage→neuroinflammation), preprint, single lab","pmids":[],"is_preprint":true}],"current_model":"NTMT1 (NRMT1) is the founding mammalian alpha-N-terminal methyltransferase that mono-, di-, and trimethylates the free alpha-amino group of proteins bearing an (Ala/Pro/Ser)-Pro-Lys N-terminal motif (after Met cleavage), using SAM as methyl donor; validated substrates include RCC1, RB, SET, CENP-A, OLA1, and PAD1; it functions as a homodimer (activated by heterotrimer formation with NRMT2, which stabilizes NRMT1 and increases its substrate affinity), is transcriptionally driven by CREB1, and is required for bipolar spindle formation, chromosome segregation, DNA damage repair, RB-mediated transcriptional repression during neurogenesis, and muscle cell differentiation."},"narrative":{"mechanistic_narrative":"NTMT1 (NRMT1) is the founding eukaryotic protein alpha-N-terminal methyltransferase, catalyzing mono-, di-, and trimethylation of the free alpha-amino group of substrates bearing an (Ala/Pro/Ser)-Pro-Lys N-terminal motif using SAM as methyl donor [PMID:20668449]. Acting distributively, it can install all three methylation states, in contrast to its homolog NRMT2, which is principally a monomethylase recognizing the same consensus [PMID:24090352]; NRMT1 functions as a homodimer and is converted to a more active, more stable form upon heterotrimer formation with NRMT2, an activation that does not require NRMT2 catalytic activity and reflects a scaffold/stabilization mechanism rather than substrate priming [PMID:30151928]. Through N-terminal methylation of substrates including RCC1, RB, CENP-A, SET, OLA1, and PAD1 [PMID:20668449, PMID:28266506, PMID:31857877, PMID:39287128], NTMT1 governs bipolar spindle formation and chromosome segregation — loss of RCC1 or CENP-A trimethylation produces multipolar spindles, lagging chromosomes, and reduced centromeric CCAN loading [PMID:20668449, PMID:28266506]. The enzyme is required for genome maintenance and DNA double-strand break repair, and its loss sensitizes cells to genotoxic stress while enhancing proliferation and tumorigenicity, consistent with a tumor-suppressor role [PMID:25843235, PMID:25909287]. NTMT1 also controls RB-mediated transcriptional repression: its loss in mice deregulates RB phosphorylation and degradation and de-represses RB cell-cycle and apoptotic targets, with downstream consequences for neural stem cell quiescence [PMID:34711807]. NTMT1 expression is transcriptionally driven by CREB1, which binds its promoter to support recovery from serum starvation and muscle cell differentiation, where NTMT1 loss abolishes Pax7 and redirects myoblasts toward an osteoblast-like fate [PMID:34403304]. Substrate recognition is structurally defined by the peptide-binding channel, where cancer-associated mutations and peptidomimetic inhibitors that bind competitively to the peptide site alter or block trimethylation [PMID:28556566, PMID:32689795].","teleology":[{"year":2010,"claim":"Established that a dedicated enzyme installs methylation on protein N-terminal alpha-amino groups, defining NRMT1 as the first eukaryotic alpha-N-methyltransferase and linking the modification to mitotic fidelity.","evidence":"In vitro methyltransferase assays, RCC1 substrate docking/mutagenesis, and siRNA knockdown with mitotic spindle readouts","pmids":["20668449"],"confidence":"High","gaps":["Substrate scope beyond RCC1 and RB undefined","Structural basis of motif recognition not yet resolved"]},{"year":2013,"claim":"Resolved the division of labor between paralogs, showing NRMT1 is a distributive tri-methylase while NRMT2 is a monomethylase on the same consensus.","evidence":"In vitro enzyme assays with MS and co-expression experiments","pmids":["24090352"],"confidence":"High","gaps":["Mechanism of NRMT1/NRMT2 cooperation (priming vs. stabilization) unresolved at this stage"]},{"year":2015,"claim":"Defined the organismal and genome-maintenance requirement for NRMT1, connecting its loss to oxidative damage handling and DNA repair deficits.","evidence":"Constitutive knockout mouse phenotyping, ROS measurement, and fibroblast oxidative damage assays; parallel breast cancer knockdown studies","pmids":["25843235","25909287"],"confidence":"High","gaps":["No direct biochemical mechanism linking N-terminal methylation to DSB repair","Causal substrate driving the repair phenotype not identified"]},{"year":2017,"claim":"Identified CENP-A as an in vivo trimethylation target and the peptide-binding channel as a structural determinant of methylation-state specificity, explaining how cancer mutations reprogram enzyme output.","evidence":"In vivo trimethylation assays, centromere immunofluorescence; site-directed mutagenesis of cancer mutants with in vitro activity assays","pmids":["28266506","28556566"],"confidence":"High","gaps":["Full crystal structure of the substrate complex not yet available","How altered methylation states affect tumorigenesis in vivo untested"]},{"year":2018,"claim":"Settled the paralog cooperation mechanism: NRMT2 forms a heterotrimer with the NRMT1 homodimer and activates it by increasing stability and substrate affinity, independent of NRMT2 catalysis.","evidence":"Analytical ultracentrifugation, reciprocal Co-IP, half-life assays, and catalytic-dead rescue","pmids":["30151928"],"confidence":"High","gaps":["Structural model of the heterotrimer not experimentally determined","Physiological contexts requiring heterotrimer activation unclear"]},{"year":2019,"claim":"Expanded the in vivo substrate repertoire via activity-based profiling, identifying OLA1 as a cellular NTMT1 target.","evidence":"Hey-SAM chemoproteomic profiling with CRISPR-Cas9 knockout validation and MS","pmids":["31857877"],"confidence":"Medium","gaps":["Functional consequence of OLA1 N-terminal methylation not established"]},{"year":2020,"claim":"Provided the structural and chemical-biology toolkit, with a co-crystal structure showing peptide-competitive, SAM-noncompetitive inhibition and a cell-permeable analogue achieving target engagement.","evidence":"Co-crystallization/X-ray structure with BM30, IC50 assays, 41-MT selectivity panel, cellular RCC1/SET methylation readout","pmids":["32689795"],"confidence":"High","gaps":["In vivo efficacy of inhibitors untested","Cross-reactivity boundaries only partially mapped"]},{"year":2021,"claim":"Placed NRMT1 in a transcriptional circuit (CREB1-driven) and downstream signaling axes, controlling RB-dependent repression in neurogenesis and CREB1-dependent myogenic differentiation.","evidence":"Knockout mouse RB phosphorylation/target gene analysis; luciferase/promoter binding and CRISPR knockout in C2C12 cells; bisubstrate inhibitor chemoproteomics defining HemK2-Trm112 cross-reactivity","pmids":["34711807","34403304","34192867"],"confidence":"Medium","gaps":["Direct substrate mediating RB regulation not pinned down","Mechanism linking N-terminal methylation to Pax7/lineage choice unresolved"]},{"year":2024,"claim":"Extended substrate-level consequences of methylation, showing NTMT1 methylation of PAD1 stabilizes it and remodels its interactions without altering its catalytic activity.","evidence":"Biochemical methylation, cellular half-life, and Co-IP/interaction proteomics with WT vs. non-methylatable PAD1","pmids":["39287128"],"confidence":"Medium","gaps":["Physiological pathway impacted by PAD1 stabilization unclear","Generalizability of methylation-driven half-life control across substrates untested"]},{"year":2025,"claim":"Linked NRMT1 loss to progressive neuroinflammation via p35-to-p25 cleavage and glial activation, connecting its neurogenesis role to neurodegeneration.","evidence":"Constitutive Nrmt1-/- mouse with p35/p25 Western blots, cytokine and complement assays, glial immunofluorescence (preprint)","pmids":[],"confidence":"Medium","gaps":["Preprint, single lab, not peer-reviewed","Mechanistic link from N-terminal methylation to p35/p25 processing not biochemically defined"]},{"year":null,"claim":"How NTMT1 substrate selection is regulated in different tissues and which specific methylated substrates drive each phenotype (DNA repair, neurogenesis, myogenesis) remain open.","evidence":"No single experiment in the corpus connects an individual substrate methylation event to the organismal repair or differentiation phenotypes","pmids":[],"confidence":"Low","gaps":["Causal substrate for each in vivo phenotype unresolved","No structure of the activated NRMT1/NRMT2 heterotrimer","Tissue-specific regulation of activity beyond CREB1 transcription unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,1,5,7,8,12]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,2,12]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,2]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,2]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[3,4]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,12]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[9,10]}],"complexes":["NRMT1 homodimer","NRMT1-NRMT2 heterotrimer"],"partners":["NRMT2","RCC1","RB1","CENP-A","OLA1","PAD1","SET"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9BV86","full_name":"N-terminal Xaa-Pro-Lys N-methyltransferase 1","aliases":["Alpha N-terminal protein methyltransferase 1A","Methyltransferase-like protein 11A","N-terminal RCC1 methyltransferase","X-Pro-Lys N-terminal protein methyltransferase 1A","NTM1A"],"length_aa":223,"mass_kda":25.4,"function":"Distributive alpha-N-methyltransferase that methylates the N-terminus of target proteins containing the N-terminal motif [Ala/Gly/Pro/Ser]-Pro-Lys when the initiator Met is cleaved. Specifically catalyzes mono-, di- or tri-methylation of the exposed alpha-amino group of the Ala, Gly or Ser residue in the [Ala/Gly/Ser]-Pro-Lys motif and mono- or di-methylation of Pro in the Pro-Pro-Lys motif. Some of the substrates may be primed by NTMT2-mediated monomethylation (PubMed:24090352). Catalyzes the trimethylation of the N-terminal Gly in CENPA (after removal of Met-1). Responsible for the N-terminal methylation of KLHL31, MYL2, MYL3, RB1, RCC1, RPL23A and SET. Required during mitosis for normal bipolar spindle formation and chromosome segregation via its action on RCC1","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9BV86/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NTMT1","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DRG1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/NTMT1","total_profiled":1310},"omim":[{"mim_id":"613560","title":"N-TERMINAL X-PRO-LYS N-METHYLTRANSFERASE 1; NTMT1","url":"https://www.omim.org/entry/613560"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NTMT1"},"hgnc":{"alias_symbol":["AD-003","HOMT1A","NRMT1","NRMT"],"prev_symbol":["C9orf32","METTL11A"]},"alphafold":{"accession":"Q9BV86","domains":[{"cath_id":"3.40.50.150","chopping":"1-221","consensus_level":"high","plddt":97.5671,"start":1,"end":221}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BV86","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BV86-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BV86-F1-predicted_aligned_error_v6.png","plddt_mean":97.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NTMT1","jax_strain_url":"https://www.jax.org/strain/search?query=NTMT1"},"sequence":{"accession":"Q9BV86","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BV86.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BV86/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BV86"}},"corpus_meta":[{"pmid":"20668449","id":"PMC_20668449","title":"NRMT is an alpha-N-methyltransferase that methylates RCC1 and retinoblastoma protein.","date":"2010","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/20668449","citation_count":111,"is_preprint":false},{"pmid":"28266506","id":"PMC_28266506","title":"α-amino trimethylation of CENP-A by NRMT is required for full recruitment of the centromere.","date":"2017","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/28266506","citation_count":61,"is_preprint":false},{"pmid":"24090352","id":"PMC_24090352","title":"NRMT2 is an N-terminal monomethylase that primes for its homologue NRMT1.","date":"2013","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/24090352","citation_count":40,"is_preprint":false},{"pmid":"25843235","id":"PMC_25843235","title":"NRMT1 knockout mice exhibit phenotypes associated with impaired DNA repair and premature aging.","date":"2015","source":"Mechanisms of ageing and development","url":"https://pubmed.ncbi.nlm.nih.gov/25843235","citation_count":37,"is_preprint":false},{"pmid":"25909287","id":"PMC_25909287","title":"Loss of the N-terminal methyltransferase NRMT1 increases sensitivity to DNA damage and promotes mammary oncogenesis.","date":"2015","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/25909287","citation_count":32,"is_preprint":false},{"pmid":"28556566","id":"PMC_28556566","title":"Select human cancer mutants of NRMT1 alter its catalytic activity and decrease N-terminal trimethylation.","date":"2017","source":"Protein science : a publication of the Protein Society","url":"https://pubmed.ncbi.nlm.nih.gov/28556566","citation_count":25,"is_preprint":false},{"pmid":"34711807","id":"PMC_34711807","title":"Age-related neurodegeneration and cognitive impairments of NRMT1 knockout mice are preceded by misregulation of RB and abnormal neural stem cell development.","date":"2021","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/34711807","citation_count":16,"is_preprint":false},{"pmid":"32689795","id":"PMC_32689795","title":"Selective Peptidomimetic Inhibitors of NTMT1/2: Rational Design, Synthesis, Characterization, and Crystallographic Studies.","date":"2020","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/32689795","citation_count":12,"is_preprint":false},{"pmid":"34403304","id":"PMC_34403304","title":"CREB-mediated transcriptional activation of NRMT1 drives muscle differentiation.","date":"2021","source":"Transcription","url":"https://pubmed.ncbi.nlm.nih.gov/34403304","citation_count":12,"is_preprint":false},{"pmid":"30151928","id":"PMC_30151928","title":"The N-terminal methyltransferase homologs NRMT1 and NRMT2 exhibit novel regulation of activity through heterotrimer formation.","date":"2018","source":"Protein science : a publication of the Protein Society","url":"https://pubmed.ncbi.nlm.nih.gov/30151928","citation_count":12,"is_preprint":false},{"pmid":"31857877","id":"PMC_31857877","title":"In vivo methylation of OLA1 revealed by activity-based target profiling of NTMT1.","date":"2019","source":"Chemical science","url":"https://pubmed.ncbi.nlm.nih.gov/31857877","citation_count":12,"is_preprint":false},{"pmid":"35013138","id":"PMC_35013138","title":"Knockdown of NRMT enhances sensitivity of retinoblastoma cells to cisplatin through upregulation of the CENPA/Myc/Bcl2 axis.","date":"2022","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/35013138","citation_count":11,"is_preprint":false},{"pmid":"34192867","id":"PMC_34192867","title":"Chemoproteomic Study Uncovers HemK2/KMT9 As a New Target for NTMT1 Bisubstrate Inhibitors.","date":"2021","source":"ACS chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/34192867","citation_count":9,"is_preprint":false},{"pmid":"36634151","id":"PMC_36634151","title":"Structure-Activity Relationship Studies of Venglustat on NTMT1 Inhibition.","date":"2023","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/36634151","citation_count":8,"is_preprint":false},{"pmid":"38014887","id":"PMC_38014887","title":"Pan-cancer analysis reveals the pro-oncogenic role of N6-methyladenosine (m6A)-regulated NTMT1 in head and neck squamous cell carcinoma.","date":"2023","source":"Journal of biochemical and molecular toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/38014887","citation_count":2,"is_preprint":false},{"pmid":"39287128","id":"PMC_39287128","title":"Characterizations of Protein Arginine Deiminase 1 as a Substrate of NTMT1: Implications of Nα-Methylation in Protein Stability and Interaction.","date":"2024","source":"Journal of proteome 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detection","date":"2024-08-02","source":"bioRxiv","url":"https://doi.org/10.1101/2024.07.31.24311206","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11005,"output_tokens":3664,"usd":0.043987,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11328,"output_tokens":3689,"usd":0.074432,"stage2_stop_reason":"end_turn"},"total_usd":0.118419,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"NRMT1 (NRMT) is the first identified eukaryotic alpha-N-methyltransferase, catalyzing mono-, di-, and trimethylation of the free alpha-amino group of proteins bearing the N-terminal motif (Ala/Pro/Ser)-Pro-Lys (after Met cleavage). Substrates include RCC1 and retinoblastoma protein (RB). The NRMT recognition sequence was defined by substrate docking and mutational analysis of RCC1. Knockdown of NRMT recapitulates the multi-spindle phenotype seen with methylation-defective RCC1 mutants, establishing a role in bipolar spindle formation and chromosome segregation.\",\n      \"method\": \"In vitro methyltransferase assay, substrate docking, mutational analysis of RCC1, siRNA knockdown with mitotic phenotype readout, mass spectrometry\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro enzymatic reconstitution, mutagenesis, and functional KD phenotype; foundational discovery paper with multiple orthogonal methods\",\n      \"pmids\": [\"20668449\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"NRMT1 is a distributive methyltransferase capable of mono-, di-, and trimethylation of N-terminal substrates, whereas its homolog NRMT2 is primarily a monomethylase recognizing the same consensus sequences. Concurrent expression of NRMT1 and NRMT2 accelerates production of trimethylation, with NRMT2 proposed to prime substrates for NRMT1-mediated trimethylation.\",\n      \"method\": \"In vitro enzyme assays, mass spectrometry, co-expression experiments\",\n      \"journal\": \"The Biochemical Journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzyme assays with MS validation, single lab but two orthogonal methods clearly distinguishing catalytic activities\",\n      \"pmids\": [\"24090352\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CENP-A undergoes alpha-amino trimethylation by NRMT1 in vivo. Loss of this trimethylation reduces CENP-T and CENP-I CCAN components at the centromere, causes lagging chromosomes and spindle pole defects, and reduces cell survival.\",\n      \"method\": \"In vivo trimethylation assay, NRMT knockdown/knockout, immunofluorescence at centromeres, chromosome segregation assays\",\n      \"journal\": \"Nature Communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function with defined cellular phenotype, substrate identification validated in vivo, multiple orthogonal readouts\",\n      \"pmids\": [\"28266506\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Complete loss of NRMT1 in knockout mice results in decreased body size, female-specific infertility, kyphosis, decreased mitochondrial function, and early-onset liver degeneration. NRMT1 knockout mouse embryonic fibroblasts show decreased capacity for handling oxidative damage, positioning NRMT1 as required for normal DNA repair and genome maintenance.\",\n      \"method\": \"Constitutive knockout mouse generation, phenotypic analysis, ROS measurement, fibroblast oxidative damage assays\",\n      \"journal\": \"Mechanisms of Ageing and Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — constitutive KO mouse with multiple defined phenotypic readouts across tissues and cell types\",\n      \"pmids\": [\"25843235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"NRMT1 knockdown significantly enhances sensitivity of breast cancer cell lines to etoposide and gamma-irradiation, and increases proliferation, invasive potential, anchorage-independent growth, and xenograft tumor size, positioning NRMT1 as a tumor suppressor involved in DNA double-strand break repair.\",\n      \"method\": \"siRNA knockdown, DNA damage sensitivity assays (etoposide, gamma-irradiation), cell proliferation, invasion, soft agar, xenograft\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with multiple cellular phenotype readouts in a single lab, but no direct biochemical mechanism for DSB repair established\",\n      \"pmids\": [\"25909287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Cancer-associated NRMT1 mutants N209I (endometrial cancer) and P211S (lung cancer), located in the peptide-binding channel, display decreased trimethylase activity and increased mono/dimethylase activity with slower trimethylation rates and requirement for higher substrate concentration, identifying the peptide-binding channel as a structural determinant of enzyme specificity distinct from active-site aromatic residues.\",\n      \"method\": \"Site-directed mutagenesis of active-site aromatic residues and cancer mutants, in vitro enzyme activity assays, expression in WT and NRMT1-null cells\",\n      \"journal\": \"Protein Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct mutagenesis with in vitro enzymatic activity characterization, single lab, multiple orthogonal assays\",\n      \"pmids\": [\"28556566\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"NRMT1 primarily exists as a homodimer while NRMT2 exists as a monomer; when co-expressed they form a heterotrimer. NRMT2 increases NRMT1 stability (half-life) and substrate affinity, thereby activating NRMT1 trimethylation activity. The catalytic activity of NRMT2 is not required for this activation, supporting a stability/scaffold model rather than a priming model.\",\n      \"method\": \"Analytical ultracentrifugation, co-immunoprecipitation, molecular modeling, half-life assays, enzyme activity assays\",\n      \"journal\": \"Protein Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — AUC for complex stoichiometry, reciprocal Co-IP for in vivo binding, catalytic-dead mutant rescue experiment; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"30151928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Activity-based substrate profiling using Hey-SAM identified OLA1 (Obg-like ATPase 1) as a novel substrate of NTMT1 methylated in vivo; this was validated using NTMT1 knockout HEK293FT cells generated by CRISPR-Cas9.\",\n      \"method\": \"Activity-based chemoproteomic profiling with Hey-SAM, CRISPR-Cas9 knockout validation, MS\",\n      \"journal\": \"Chemical Science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — activity-based profiling plus KO cellular validation, single lab\",\n      \"pmids\": [\"31857877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Crystal structure of NTMT1 co-crystallized with peptidomimetic inhibitor BM30 reveals that the compound is a competitive inhibitor to the peptide substrate and noncompetitive to SAM, binding in the peptide substrate binding site. BM30 shows >100-fold selectivity for NTMT1/2 over 41 other methyltransferases. A cell-permeable analogue DC432 decreases N-terminal methylation of RCC1 and SET in HCT116 cells.\",\n      \"method\": \"Cocrystallization/X-ray structure, biochemical IC50 assays, selectivity panel against 41 MTs, cellular N-terminal methylation assay\",\n      \"journal\": \"Journal of Medicinal Chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with bound inhibitor, biochemical mechanism of inhibition defined, cellular target engagement validated\",\n      \"pmids\": [\"32689795\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"NRMT1 loss in knockout mice causes misregulation of RB phosphorylation and degradation, and de-repression of RB target genes involved in cell cycle as well as the apoptosis-promoting RB target Noxa, establishing that NRMT1 regulates RB transcriptional repression during neurogenesis to promote neural stem cell quiescence.\",\n      \"method\": \"Constitutive Nrmt1-/- mouse, Western blotting for RB phosphorylation/degradation, gene expression analysis of RB targets, immunofluorescence, behavioral assays\",\n      \"journal\": \"Cell Death & Disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with defined pathway placement (NRMT1→RB phosphorylation/stability→target gene de-repression), single lab\",\n      \"pmids\": [\"34711807\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CREB1 is the major transcriptional activator of NRMT1; CREB1 binds the NRMT1 minimal promoter and drives its expression during recovery from serum starvation and muscle cell differentiation. Knockout of NRMT1 in C2C12 myoblasts abolishes Pax7 expression, prevents muscle differentiation, and causes transdifferentiation toward an osteoblast-like fate.\",\n      \"method\": \"Luciferase reporter assay, promoter binding assay, CRISPR/Cas9 knockout in C2C12 cells, alkaline phosphatase and collagen expression assays, serum starvation/differentiation experiments\",\n      \"journal\": \"Transcription\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase and binding assays for transcriptional mechanism, CRISPR KO for cellular phenotype, single lab, two orthogonal methods\",\n      \"pmids\": [\"34403304\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A bisubstrate NTMT1 inhibitor NAH-C3-GPKK also potently inhibits the methyltransferase complex HemK2-Trm112 (KMT9-Trm112), as revealed by chemoproteomic pulldown with a biotinylated probe analogue; this cross-reactivity defines a selectivity boundary for NTMT1 bisubstrate inhibitors.\",\n      \"method\": \"Chemoproteomic pulldown, biochemical inhibition assays, competitor displacement with NAH-C3-GPKK\",\n      \"journal\": \"ACS Chemical Biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — chemoproteomic method plus biochemical validation, single lab\",\n      \"pmids\": [\"34192867\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PAD1 (protein arginine deiminase 1) is a substrate of NTMT1; NTMT1-mediated Nα-methylation of PAD1 increases PAD1 protein half-life and modulates its protein-protein interactions in HEK293T cells without affecting PAD1 enzymatic activity or cellular localization.\",\n      \"method\": \"Biochemical methylation assay, cellular half-life assay, co-immunoprecipitation/proteomic interaction profiling in HEK293T cells with WT vs. non-methylatable PAD1\",\n      \"journal\": \"Journal of Proteome Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical and cellular assays with multiple readouts, single lab\",\n      \"pmids\": [\"39287128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In Nrmt1-/- mice, onset of neuronal apoptosis corresponds to increased cleavage of p35 into the CDK5 activator p25, which promotes neuroinflammation. Nrmt1-/- brains exhibit pro-inflammatory cytokine signaling, astrogliosis, complement activation, microgliosis, and compromised blood-brain barrier markers, with no compensatory anti-inflammatory response, linking NRMT1-dependent neurogenesis defects to progressive neuroinflammation and neurodegeneration.\",\n      \"method\": \"Constitutive Nrmt1-/- mouse, Western blotting for p35/p25, cytokine assays, immunofluorescence for glial markers, complement assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — KO mouse with pathway placement (NRMT1→p35/p25 cleavage→neuroinflammation), preprint, single lab\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"NTMT1 (NRMT1) is the founding mammalian alpha-N-terminal methyltransferase that mono-, di-, and trimethylates the free alpha-amino group of proteins bearing an (Ala/Pro/Ser)-Pro-Lys N-terminal motif (after Met cleavage), using SAM as methyl donor; validated substrates include RCC1, RB, SET, CENP-A, OLA1, and PAD1; it functions as a homodimer (activated by heterotrimer formation with NRMT2, which stabilizes NRMT1 and increases its substrate affinity), is transcriptionally driven by CREB1, and is required for bipolar spindle formation, chromosome segregation, DNA damage repair, RB-mediated transcriptional repression during neurogenesis, and muscle cell differentiation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NTMT1 (NRMT1) is the founding eukaryotic protein alpha-N-terminal methyltransferase, catalyzing mono-, di-, and trimethylation of the free alpha-amino group of substrates bearing an (Ala/Pro/Ser)-Pro-Lys N-terminal motif using SAM as methyl donor [#0]. Acting distributively, it can install all three methylation states, in contrast to its homolog NRMT2, which is principally a monomethylase recognizing the same consensus [#1]; NRMT1 functions as a homodimer and is converted to a more active, more stable form upon heterotrimer formation with NRMT2, an activation that does not require NRMT2 catalytic activity and reflects a scaffold/stabilization mechanism rather than substrate priming [#6]. Through N-terminal methylation of substrates including RCC1, RB, CENP-A, SET, OLA1, and PAD1 [#0, #2, #7, #12], NTMT1 governs bipolar spindle formation and chromosome segregation — loss of RCC1 or CENP-A trimethylation produces multipolar spindles, lagging chromosomes, and reduced centromeric CCAN loading [#0, #2]. The enzyme is required for genome maintenance and DNA double-strand break repair, and its loss sensitizes cells to genotoxic stress while enhancing proliferation and tumorigenicity, consistent with a tumor-suppressor role [#3, #4]. NTMT1 also controls RB-mediated transcriptional repression: its loss in mice deregulates RB phosphorylation and degradation and de-represses RB cell-cycle and apoptotic targets, with downstream consequences for neural stem cell quiescence [#9]. NTMT1 expression is transcriptionally driven by CREB1, which binds its promoter to support recovery from serum starvation and muscle cell differentiation, where NTMT1 loss abolishes Pax7 and redirects myoblasts toward an osteoblast-like fate [#10]. Substrate recognition is structurally defined by the peptide-binding channel, where cancer-associated mutations and peptidomimetic inhibitors that bind competitively to the peptide site alter or block trimethylation [#5, #8].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established that a dedicated enzyme installs methylation on protein N-terminal alpha-amino groups, defining NRMT1 as the first eukaryotic alpha-N-methyltransferase and linking the modification to mitotic fidelity.\",\n      \"evidence\": \"In vitro methyltransferase assays, RCC1 substrate docking/mutagenesis, and siRNA knockdown with mitotic spindle readouts\",\n      \"pmids\": [\"20668449\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Substrate scope beyond RCC1 and RB undefined\", \"Structural basis of motif recognition not yet resolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved the division of labor between paralogs, showing NRMT1 is a distributive tri-methylase while NRMT2 is a monomethylase on the same consensus.\",\n      \"evidence\": \"In vitro enzyme assays with MS and co-expression experiments\",\n      \"pmids\": [\"24090352\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of NRMT1/NRMT2 cooperation (priming vs. stabilization) unresolved at this stage\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the organismal and genome-maintenance requirement for NRMT1, connecting its loss to oxidative damage handling and DNA repair deficits.\",\n      \"evidence\": \"Constitutive knockout mouse phenotyping, ROS measurement, and fibroblast oxidative damage assays; parallel breast cancer knockdown studies\",\n      \"pmids\": [\"25843235\", \"25909287\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No direct biochemical mechanism linking N-terminal methylation to DSB repair\", \"Causal substrate driving the repair phenotype not identified\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified CENP-A as an in vivo trimethylation target and the peptide-binding channel as a structural determinant of methylation-state specificity, explaining how cancer mutations reprogram enzyme output.\",\n      \"evidence\": \"In vivo trimethylation assays, centromere immunofluorescence; site-directed mutagenesis of cancer mutants with in vitro activity assays\",\n      \"pmids\": [\"28266506\", \"28556566\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full crystal structure of the substrate complex not yet available\", \"How altered methylation states affect tumorigenesis in vivo untested\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Settled the paralog cooperation mechanism: NRMT2 forms a heterotrimer with the NRMT1 homodimer and activates it by increasing stability and substrate affinity, independent of NRMT2 catalysis.\",\n      \"evidence\": \"Analytical ultracentrifugation, reciprocal Co-IP, half-life assays, and catalytic-dead rescue\",\n      \"pmids\": [\"30151928\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural model of the heterotrimer not experimentally determined\", \"Physiological contexts requiring heterotrimer activation unclear\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Expanded the in vivo substrate repertoire via activity-based profiling, identifying OLA1 as a cellular NTMT1 target.\",\n      \"evidence\": \"Hey-SAM chemoproteomic profiling with CRISPR-Cas9 knockout validation and MS\",\n      \"pmids\": [\"31857877\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of OLA1 N-terminal methylation not established\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Provided the structural and chemical-biology toolkit, with a co-crystal structure showing peptide-competitive, SAM-noncompetitive inhibition and a cell-permeable analogue achieving target engagement.\",\n      \"evidence\": \"Co-crystallization/X-ray structure with BM30, IC50 assays, 41-MT selectivity panel, cellular RCC1/SET methylation readout\",\n      \"pmids\": [\"32689795\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo efficacy of inhibitors untested\", \"Cross-reactivity boundaries only partially mapped\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placed NRMT1 in a transcriptional circuit (CREB1-driven) and downstream signaling axes, controlling RB-dependent repression in neurogenesis and CREB1-dependent myogenic differentiation.\",\n      \"evidence\": \"Knockout mouse RB phosphorylation/target gene analysis; luciferase/promoter binding and CRISPR knockout in C2C12 cells; bisubstrate inhibitor chemoproteomics defining HemK2-Trm112 cross-reactivity\",\n      \"pmids\": [\"34711807\", \"34403304\", \"34192867\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct substrate mediating RB regulation not pinned down\", \"Mechanism linking N-terminal methylation to Pax7/lineage choice unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extended substrate-level consequences of methylation, showing NTMT1 methylation of PAD1 stabilizes it and remodels its interactions without altering its catalytic activity.\",\n      \"evidence\": \"Biochemical methylation, cellular half-life, and Co-IP/interaction proteomics with WT vs. non-methylatable PAD1\",\n      \"pmids\": [\"39287128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological pathway impacted by PAD1 stabilization unclear\", \"Generalizability of methylation-driven half-life control across substrates untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked NRMT1 loss to progressive neuroinflammation via p35-to-p25 cleavage and glial activation, connecting its neurogenesis role to neurodegeneration.\",\n      \"evidence\": \"Constitutive Nrmt1-/- mouse with p35/p25 Western blots, cytokine and complement assays, glial immunofluorescence (preprint)\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, single lab, not peer-reviewed\", \"Mechanistic link from N-terminal methylation to p35/p25 processing not biochemically defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NTMT1 substrate selection is regulated in different tissues and which specific methylated substrates drive each phenotype (DNA repair, neurogenesis, myogenesis) remain open.\",\n      \"evidence\": \"No single experiment in the corpus connects an individual substrate methylation event to the organismal repair or differentiation phenotypes\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Causal substrate for each in vivo phenotype unresolved\", \"No structure of the activated NRMT1/NRMT2 heterotrimer\", \"Tissue-specific regulation of activity beyond CREB1 transcription unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 1, 5, 7, 8, 12]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 2, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 12]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [9, 10]}\n    ],\n    \"complexes\": [\"NRMT1 homodimer\", \"NRMT1-NRMT2 heterotrimer\"],\n    \"partners\": [\"NRMT2\", \"RCC1\", \"RB1\", \"CENP-A\", \"OLA1\", \"PAD1\", \"SET\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}