{"gene":"NOL3","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":1999,"finding":"NOL3 (Nop30) is generated by alternative 5' splice site usage from a single gene, producing two isoforms with different C-termini: one with a serine/arginine-rich C-terminus that targets the protein to the nucleus/nucleolus, and another with proline/glutamic acid dipeptides that localizes predominantly to the cytosol.","method":"Alternative splicing characterization, subcellular localization studies","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct experimental localization studies with sequence characterization, single lab but multiple approaches","pmids":["10196175"],"is_preprint":false},{"year":1999,"finding":"Nop30 (NOL3) multimerizes and binds specifically to the RS domain of the splicing factor SRp30c, but not to other splicing factors tested, as demonstrated by yeast two-hybrid, in vitro protein interaction assays, and co-immunoprecipitation.","method":"Yeast two-hybrid screen, in vitro protein interaction assay, co-immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — three orthogonal methods (yeast two-hybrid, in vitro binding, co-IP) all supporting the same interaction in a single study","pmids":["10196175"],"is_preprint":false},{"year":1999,"finding":"Overexpression of Nop30 (NOL3) changes alternative exon usage in preprotachykinin and SRp20 reporter genes, indicating NOL3 influences alternative splice site selection in vivo.","method":"Reporter gene overexpression assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — functional overexpression assay with reporter genes, single lab, consistent with binding partner data","pmids":["10196175"],"is_preprint":false},{"year":2012,"finding":"A NOL3 mutation identified in a family with familial cortical myoclonus alters post-translational modification of the NOL3 protein in vitro, implicating post-translational modification as functionally relevant.","method":"In vitro post-translational modification assay following identification of cosegregating nonsynonymous mutation by sequencing","journal":"Annals of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — in vitro PTM assay is direct but single lab, limited mechanistic detail in abstract","pmids":["22926851"],"is_preprint":false},{"year":2016,"finding":"NOL3 protein protects hippocampal neuronal cells against oxidative stress-induced apoptosis by inhibiting ROS production, DNA fragmentation, and loss of mitochondrial membrane potential, and by regulating the apoptotic signaling pathway including Bax, Bcl-2, caspase-2, -3 and -8, PARP, and p53.","method":"Tat-fused NOL3 protein transduction into H2O2-exposed HT22 cells and animal model of forebrain ischemia; Western blot of apoptotic markers","journal":"International journal of molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell and in vivo experiments with multiple apoptotic markers, single lab, no mutagenesis or reconstitution","pmids":["27221790"],"is_preprint":false},{"year":2017,"finding":"Deletion of Nol3 in mice leads to a myeloproliferative neoplasm (MPN) resembling primary myelofibrosis, characterized by expanded Thy1+LSK stem cell population with increased cell cycling, myelomonocytic differentiation bias, JAK-STAT activation, and downstream activation of CDK6 and Myc, establishing NOL3 as a tumor suppressor in myeloid cells.","method":"Nol3 knockout mouse model; flow cytometry; molecular pathway analysis (JAK-STAT, CDK6, Myc)","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockout mouse with defined cellular and molecular phenotype, multiple downstream pathway readouts, peer-reviewed","pmids":["28232469"],"is_preprint":false},{"year":2022,"finding":"ATXN1L promotes deacetylation of histone H3 through HDAC3 and thereby suppresses NOL3 expression at the transcriptional level; ChIP assays confirmed binding of ATXN1L and HDAC3 to the NOL3 promoter.","method":"ChIP assay, immunofluorescence, Western blot, HDAC3 inhibition, ATXN1L knockout","journal":"Journal of molecular medicine (Berlin, Germany)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP confirmed promoter binding, multiple approaches, single lab","pmids":["35414011"],"is_preprint":false},{"year":2026,"finding":"ELK1 transcriptionally upregulates NOL3, which physically interacts with GRP78 to activate the PERK/CHOP branch of the unfolded protein response, amplifying adaptive ER stress and promoting proliferation and stemness in TP53-mutant colon cancer cells.","method":"Dual-luciferase reporter assay (ELK1→NOL3 transcription), co-immunoprecipitation (NOL3–GRP78 interaction), gain- and loss-of-function studies, Western blot","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP and luciferase reporter are orthogonal methods, single lab, functional validation in cell lines and xenograft","pmids":["41864308"],"is_preprint":false}],"current_model":"NOL3 is a nucleolar/nuclear protein generated by alternative splicing that binds the RS domain of splicing factor SRp30c to modulate alternative splicing, acts as an anti-apoptotic regulator by suppressing caspase activation and Bax/Bcl-2 signaling downstream of oxidative stress, functions as a tumor suppressor in myeloid cells by restraining JAK-STAT/CDK6/Myc signaling, is transcriptionally regulated through HDAC3-mediated histone deacetylation at its promoter, and physically interacts with GRP78 downstream of ELK1 to activate the PERK/CHOP unfolded protein response branch in TP53-mutant cancer cells."},"narrative":{"mechanistic_narrative":"NOL3 is a dual-function protein that originated in the literature as a nuclear/nucleolar splicing modulator and was subsequently established as an anti-apoptotic regulator and context-dependent tumor suppressor [PMID:10196175, PMID:28232469]. The gene produces two isoforms by alternative 5' splice site usage: a serine/arginine-rich C-terminal form targeted to the nucleus/nucleolus and a proline/glutamic acid-rich form that is predominantly cytosolic [PMID:10196175]. The nuclear form multimerizes and binds specifically the RS domain of the splicing factor SRp30c, and its overexpression shifts alternative exon usage in reporter genes, defining a role in alternative splice site selection [PMID:10196175]. In cells subjected to oxidative stress, NOL3 protects against apoptosis by limiting ROS production, mitochondrial depolarization, and DNA fragmentation while modulating Bax/Bcl-2, caspase-2/-3/-8, PARP, and p53 signaling [PMID:27221790]. In the myeloid compartment NOL3 acts as a tumor suppressor: its loss in mice drives a myeloproliferative neoplasm resembling primary myelofibrosis through stem cell expansion, JAK-STAT activation, and downstream CDK6 and Myc induction [PMID:28232469]. NOL3 expression is transcriptionally controlled, being repressed by ATXN1L/HDAC3-mediated histone H3 deacetylation at its promoter and induced by ELK1; ELK1-driven NOL3 binds GRP78 to activate the PERK/CHOP arm of the unfolded protein response and promote proliferation and stemness in TP53-mutant colon cancer cells [PMID:35414011, PMID:41864308]. A cosegregating NOL3 mutation that alters the protein's post-translational modification has been linked to familial cortical myoclonus [PMID:22926851].","teleology":[{"year":1999,"claim":"Established that NOL3 is produced as two isoforms with distinct C-termini and localizations, defining how a single gene generates nuclear/nucleolar versus cytosolic protein pools.","evidence":"Alternative splicing characterization and subcellular localization studies","pmids":["10196175"],"confidence":"Medium","gaps":["Functional consequences of the two isoforms not separately dissected","No determination of which isoform predominates in different tissues"]},{"year":1999,"claim":"Answered what nuclear NOL3 binds by identifying a specific, multimerization-dependent interaction with the RS domain of SRp30c, placing NOL3 in the splicing machinery.","evidence":"Yeast two-hybrid, in vitro binding, and co-immunoprecipitation","pmids":["10196175"],"confidence":"High","gaps":["Structural basis of RS-domain recognition not resolved","Whether the interaction occurs on assembled spliceosomes in vivo not shown"]},{"year":1999,"claim":"Demonstrated functional consequence of NOL3 in splicing by showing overexpression alters alternative exon usage, linking the SRp30c interaction to splice site selection.","evidence":"Reporter gene overexpression assays (preprotachykinin, SRp20)","pmids":["10196175"],"confidence":"Medium","gaps":["Endogenous splicing targets not defined","Direction of effect at native genes not mapped"]},{"year":2012,"claim":"Connected NOL3 to human disease by identifying a cosegregating mutation in familial cortical myoclonus that alters the protein's post-translational modification.","evidence":"Mutation sequencing in a family plus in vitro PTM assay","pmids":["22926851"],"confidence":"Medium","gaps":["Identity of the affected modification not detailed","Mechanistic link between altered PTM and neuronal phenotype not established"]},{"year":2016,"claim":"Defined an anti-apoptotic, cytoprotective role by showing NOL3 protects neurons against oxidative-stress apoptosis and modulates mitochondrial and caspase signaling.","evidence":"Tat-NOL3 transduction into H2O2-exposed HT22 cells and a forebrain ischemia model with apoptotic-marker Western blots","pmids":["27221790"],"confidence":"Medium","gaps":["Direct molecular targets among caspases/Bcl-2 family not identified","No mutagenesis to map the protective domain"]},{"year":2017,"claim":"Established NOL3 as a myeloid tumor suppressor by showing its deletion causes a myeloproliferative neoplasm via stem cell expansion and JAK-STAT/CDK6/Myc activation.","evidence":"Nol3 knockout mouse with flow cytometry and pathway analysis","pmids":["28232469"],"confidence":"High","gaps":["Direct biochemical step by which NOL3 restrains JAK-STAT not identified","Whether splicing or apoptotic function underlies suppression unresolved"]},{"year":2022,"claim":"Revealed how NOL3 expression is set transcriptionally, showing ATXN1L recruits HDAC3 to deacetylate histone H3 and repress the NOL3 promoter.","evidence":"ChIP, HDAC3 inhibition, ATXN1L knockout, immunofluorescence and Western blot","pmids":["35414011"],"confidence":"Medium","gaps":["Cellular context where this regulation dominates not generalized","Link between NOL3 repression and downstream phenotype not fully traced"]},{"year":2026,"claim":"Connected NOL3 to ER-stress signaling by showing ELK1-induced NOL3 binds GRP78 to activate the PERK/CHOP UPR branch and promote proliferation/stemness in TP53-mutant cancer.","evidence":"Dual-luciferase reporter, co-IP, gain/loss-of-function studies, and xenografts","pmids":["41864308"],"confidence":"Medium","gaps":["Structural basis and domain mediating GRP78 binding not defined","Reconciliation of pro-tumor UPR role with myeloid tumor-suppressor role not addressed"]},{"year":null,"claim":"How NOL3's splicing, anti-apoptotic, transcriptional-target, and UPR-modulating activities are integrated into one mechanistic model — and which isoform mediates each — remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model linking isoform/domain to each function","Direct molecular substrates/targets in apoptosis and JAK-STAT suppression unidentified","Apparent context-dependent opposing roles (tumor suppressor vs pro-tumor) not mechanistically reconciled"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[1,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,7]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[4]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[7]}],"complexes":[],"partners":["SRP30C","GRP78","ATXN1L","HDAC3","ELK1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O60936","full_name":"Nucleolar protein 3","aliases":["Apoptosis repressor with CARD","Muscle-enriched cytoplasmic protein","Myp","Nucleolar protein of 30 kDa","Nop30"],"length_aa":208,"mass_kda":22.6,"function":"May be involved in RNA splicing Functions as an apoptosis repressor that blocks multiple modes of cell death. Inhibits extrinsic apoptotic pathways through two different ways. Firstly by interacting with FAS and FADD upon FAS activation blocking death-inducing signaling complex (DISC) assembly (By similarity). Secondly by interacting with CASP8 in a mitochondria localization- and phosphorylation-dependent manner, limiting the amount of soluble CASP8 available for DISC-mediated activation (By similarity). Inhibits intrinsic apoptotic pathway in response to a wide range of stresses, through its interaction with BAX resulting in BAX inactivation, preventing mitochondrial dysfunction and release of pro-apoptotic factors (PubMed:15004034). Inhibits calcium-mediated cell death by functioning as a cytosolic calcium buffer, dissociating its interaction with CASP8 and maintaining calcium homeostasis (PubMed:15509781). Negatively regulates oxidative stress-induced apoptosis by phosphorylation-dependent suppression of the mitochondria-mediated intrinsic pathway, by blocking CASP2 activation and BAX translocation (By similarity). Negatively regulates hypoxia-induced apoptosis in part by inhibiting the release of cytochrome c from mitochondria in a caspase-independent manner (By similarity). Also inhibits TNF-induced necrosis by preventing TNF-signaling pathway through TNFRSF1A interaction abrogating the recruitment of RIPK1 to complex I (By similarity). Finally through its role as apoptosis repressor, promotes vascular remodeling through inhibition of apoptosis and stimulation of proliferation, in response to hypoxia (By similarity). Inhibits too myoblast differentiation through caspase inhibition (By similarity)","subcellular_location":"Cytoplasm; Mitochondrion; Sarcoplasmic reticulum; Membrane","url":"https://www.uniprot.org/uniprotkb/O60936/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NOL3","classification":"Not Classified","n_dependent_lines":12,"n_total_lines":1208,"dependency_fraction":0.009933774834437087},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/NOL3","total_profiled":1310},"omim":[{"mim_id":"614937","title":"MYOCLONUS, FAMILIAL, 1; MYOCL1","url":"https://www.omim.org/entry/614937"},{"mim_id":"611462","title":"PHOSPHATIDYLINOSITOL 3-KINASE, REGULATORY SUBUNIT 6; PIK3R6","url":"https://www.omim.org/entry/611462"},{"mim_id":"605235","title":"NUCLEOLAR PROTEIN 3; NOL3","url":"https://www.omim.org/entry/605235"},{"mim_id":"604593","title":"KINESIN FAMILY MEMBER 5C; KIF5C","url":"https://www.omim.org/entry/604593"},{"mim_id":"602821","title":"KINESIN FAMILY MEMBER 5A; KIF5A","url":"https://www.omim.org/entry/602821"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NOL3"},"hgnc":{"alias_symbol":["ARC","NOP30","MYP","CARD2"],"prev_symbol":[]},"alphafold":{"accession":"O60936","domains":[{"cath_id":"1.10.533.10","chopping":"9-87","consensus_level":"high","plddt":96.1324,"start":9,"end":87}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O60936","model_url":"https://alphafold.ebi.ac.uk/files/AF-O60936-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O60936-F1-predicted_aligned_error_v6.png","plddt_mean":71.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NOL3","jax_strain_url":"https://www.jax.org/strain/search?query=NOL3"},"sequence":{"accession":"O60936","fasta_url":"https://rest.uniprot.org/uniprotkb/O60936.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O60936/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O60936"}},"corpus_meta":[{"pmid":"10196175","id":"PMC_10196175","title":"Alternative splicing determines the intracellular localization of the novel nuclear protein Nop30 and its interaction with the splicing factor SRp30c.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10196175","citation_count":35,"is_preprint":false},{"pmid":"12781975","id":"PMC_12781975","title":"Cleavage site of a major yolk protein (MYP) determined by cDNA isolation and amino acid sequencing in sea urchin, Hemicentrotus pulcherrimus.","date":"2003","source":"Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12781975","citation_count":27,"is_preprint":false},{"pmid":"22926851","id":"PMC_22926851","title":"Familial cortical myoclonus with a mutation in NOL3.","date":"2012","source":"Annals of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/22926851","citation_count":18,"is_preprint":false},{"pmid":"27221790","id":"PMC_27221790","title":"Tat-NOL3 protects against hippocampal neuronal cell death induced by oxidative stress through the regulation of apoptotic pathways.","date":"2016","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/27221790","citation_count":17,"is_preprint":false},{"pmid":"35414011","id":"PMC_35414011","title":"Possible implication of miR-142-3p in coronary microembolization induced myocardial injury via ATXN1L/HDAC3/NOL3 axis.","date":"2022","source":"Journal of molecular medicine (Berlin, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/35414011","citation_count":12,"is_preprint":false},{"pmid":"28232469","id":"PMC_28232469","title":"A myeloid tumor suppressor role for NOL3.","date":"2017","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28232469","citation_count":11,"is_preprint":false},{"pmid":"41040951","id":"PMC_41040951","title":"The Role of NOL3 in Colon Adenocarcinoma Metastasis and Its Association With DNA Methylation.","date":"2025","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/41040951","citation_count":1,"is_preprint":false},{"pmid":"41286470","id":"PMC_41286470","title":"Decoding colorectal cancer chemotherapy and immunotherapy resistance: revealing the role of NOL3 using single-cell RNA sequencing and machine learning.","date":"2025","source":"Clinical and experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41286470","citation_count":0,"is_preprint":false},{"pmid":"41864308","id":"PMC_41864308","title":"ELK1/NOL3/GRP78 axis regulates proliferation and stemness in TP53-mutant colon cancer by enhancing adaptive endoplasmic reticulum stress.","date":"2026","source":"Biochimica et biophysica acta. Molecular basis of disease","url":"https://pubmed.ncbi.nlm.nih.gov/41864308","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7186,"output_tokens":1870,"usd":0.024804,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8775,"output_tokens":2909,"usd":0.0583,"stage2_stop_reason":"end_turn"},"total_usd":0.083104,"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\": 1999,\n      \"finding\": \"NOL3 (Nop30) is generated by alternative 5' splice site usage from a single gene, producing two isoforms with different C-termini: one with a serine/arginine-rich C-terminus that targets the protein to the nucleus/nucleolus, and another with proline/glutamic acid dipeptides that localizes predominantly to the cytosol.\",\n      \"method\": \"Alternative splicing characterization, subcellular localization studies\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct experimental localization studies with sequence characterization, single lab but multiple approaches\",\n      \"pmids\": [\"10196175\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Nop30 (NOL3) multimerizes and binds specifically to the RS domain of the splicing factor SRp30c, but not to other splicing factors tested, as demonstrated by yeast two-hybrid, in vitro protein interaction assays, and co-immunoprecipitation.\",\n      \"method\": \"Yeast two-hybrid screen, in vitro protein interaction assay, co-immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — three orthogonal methods (yeast two-hybrid, in vitro binding, co-IP) all supporting the same interaction in a single study\",\n      \"pmids\": [\"10196175\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Overexpression of Nop30 (NOL3) changes alternative exon usage in preprotachykinin and SRp20 reporter genes, indicating NOL3 influences alternative splice site selection in vivo.\",\n      \"method\": \"Reporter gene overexpression assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — functional overexpression assay with reporter genes, single lab, consistent with binding partner data\",\n      \"pmids\": [\"10196175\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"A NOL3 mutation identified in a family with familial cortical myoclonus alters post-translational modification of the NOL3 protein in vitro, implicating post-translational modification as functionally relevant.\",\n      \"method\": \"In vitro post-translational modification assay following identification of cosegregating nonsynonymous mutation by sequencing\",\n      \"journal\": \"Annals of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — in vitro PTM assay is direct but single lab, limited mechanistic detail in abstract\",\n      \"pmids\": [\"22926851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"NOL3 protein protects hippocampal neuronal cells against oxidative stress-induced apoptosis by inhibiting ROS production, DNA fragmentation, and loss of mitochondrial membrane potential, and by regulating the apoptotic signaling pathway including Bax, Bcl-2, caspase-2, -3 and -8, PARP, and p53.\",\n      \"method\": \"Tat-fused NOL3 protein transduction into H2O2-exposed HT22 cells and animal model of forebrain ischemia; Western blot of apoptotic markers\",\n      \"journal\": \"International journal of molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell and in vivo experiments with multiple apoptotic markers, single lab, no mutagenesis or reconstitution\",\n      \"pmids\": [\"27221790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Deletion of Nol3 in mice leads to a myeloproliferative neoplasm (MPN) resembling primary myelofibrosis, characterized by expanded Thy1+LSK stem cell population with increased cell cycling, myelomonocytic differentiation bias, JAK-STAT activation, and downstream activation of CDK6 and Myc, establishing NOL3 as a tumor suppressor in myeloid cells.\",\n      \"method\": \"Nol3 knockout mouse model; flow cytometry; molecular pathway analysis (JAK-STAT, CDK6, Myc)\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockout mouse with defined cellular and molecular phenotype, multiple downstream pathway readouts, peer-reviewed\",\n      \"pmids\": [\"28232469\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ATXN1L promotes deacetylation of histone H3 through HDAC3 and thereby suppresses NOL3 expression at the transcriptional level; ChIP assays confirmed binding of ATXN1L and HDAC3 to the NOL3 promoter.\",\n      \"method\": \"ChIP assay, immunofluorescence, Western blot, HDAC3 inhibition, ATXN1L knockout\",\n      \"journal\": \"Journal of molecular medicine (Berlin, Germany)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP confirmed promoter binding, multiple approaches, single lab\",\n      \"pmids\": [\"35414011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ELK1 transcriptionally upregulates NOL3, which physically interacts with GRP78 to activate the PERK/CHOP branch of the unfolded protein response, amplifying adaptive ER stress and promoting proliferation and stemness in TP53-mutant colon cancer cells.\",\n      \"method\": \"Dual-luciferase reporter assay (ELK1→NOL3 transcription), co-immunoprecipitation (NOL3–GRP78 interaction), gain- and loss-of-function studies, Western blot\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP and luciferase reporter are orthogonal methods, single lab, functional validation in cell lines and xenograft\",\n      \"pmids\": [\"41864308\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NOL3 is a nucleolar/nuclear protein generated by alternative splicing that binds the RS domain of splicing factor SRp30c to modulate alternative splicing, acts as an anti-apoptotic regulator by suppressing caspase activation and Bax/Bcl-2 signaling downstream of oxidative stress, functions as a tumor suppressor in myeloid cells by restraining JAK-STAT/CDK6/Myc signaling, is transcriptionally regulated through HDAC3-mediated histone deacetylation at its promoter, and physically interacts with GRP78 downstream of ELK1 to activate the PERK/CHOP unfolded protein response branch in TP53-mutant cancer cells.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NOL3 is a dual-function protein that originated in the literature as a nuclear/nucleolar splicing modulator and was subsequently established as an anti-apoptotic regulator and context-dependent tumor suppressor [#1, #5]. The gene produces two isoforms by alternative 5' splice site usage: a serine/arginine-rich C-terminal form targeted to the nucleus/nucleolus and a proline/glutamic acid-rich form that is predominantly cytosolic [#0]. The nuclear form multimerizes and binds specifically the RS domain of the splicing factor SRp30c, and its overexpression shifts alternative exon usage in reporter genes, defining a role in alternative splice site selection [#1, #2]. In cells subjected to oxidative stress, NOL3 protects against apoptosis by limiting ROS production, mitochondrial depolarization, and DNA fragmentation while modulating Bax/Bcl-2, caspase-2/-3/-8, PARP, and p53 signaling [#4]. In the myeloid compartment NOL3 acts as a tumor suppressor: its loss in mice drives a myeloproliferative neoplasm resembling primary myelofibrosis through stem cell expansion, JAK-STAT activation, and downstream CDK6 and Myc induction [#5]. NOL3 expression is transcriptionally controlled, being repressed by ATXN1L/HDAC3-mediated histone H3 deacetylation at its promoter and induced by ELK1; ELK1-driven NOL3 binds GRP78 to activate the PERK/CHOP arm of the unfolded protein response and promote proliferation and stemness in TP53-mutant colon cancer cells [#6, #7]. A cosegregating NOL3 mutation that alters the protein's post-translational modification has been linked to familial cortical myoclonus [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established that NOL3 is produced as two isoforms with distinct C-termini and localizations, defining how a single gene generates nuclear/nucleolar versus cytosolic protein pools.\",\n      \"evidence\": \"Alternative splicing characterization and subcellular localization studies\",\n      \"pmids\": [\"10196175\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequences of the two isoforms not separately dissected\", \"No determination of which isoform predominates in different tissues\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Answered what nuclear NOL3 binds by identifying a specific, multimerization-dependent interaction with the RS domain of SRp30c, placing NOL3 in the splicing machinery.\",\n      \"evidence\": \"Yeast two-hybrid, in vitro binding, and co-immunoprecipitation\",\n      \"pmids\": [\"10196175\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of RS-domain recognition not resolved\", \"Whether the interaction occurs on assembled spliceosomes in vivo not shown\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Demonstrated functional consequence of NOL3 in splicing by showing overexpression alters alternative exon usage, linking the SRp30c interaction to splice site selection.\",\n      \"evidence\": \"Reporter gene overexpression assays (preprotachykinin, SRp20)\",\n      \"pmids\": [\"10196175\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous splicing targets not defined\", \"Direction of effect at native genes not mapped\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Connected NOL3 to human disease by identifying a cosegregating mutation in familial cortical myoclonus that alters the protein's post-translational modification.\",\n      \"evidence\": \"Mutation sequencing in a family plus in vitro PTM assay\",\n      \"pmids\": [\"22926851\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the affected modification not detailed\", \"Mechanistic link between altered PTM and neuronal phenotype not established\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined an anti-apoptotic, cytoprotective role by showing NOL3 protects neurons against oxidative-stress apoptosis and modulates mitochondrial and caspase signaling.\",\n      \"evidence\": \"Tat-NOL3 transduction into H2O2-exposed HT22 cells and a forebrain ischemia model with apoptotic-marker Western blots\",\n      \"pmids\": [\"27221790\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular targets among caspases/Bcl-2 family not identified\", \"No mutagenesis to map the protective domain\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Established NOL3 as a myeloid tumor suppressor by showing its deletion causes a myeloproliferative neoplasm via stem cell expansion and JAK-STAT/CDK6/Myc activation.\",\n      \"evidence\": \"Nol3 knockout mouse with flow cytometry and pathway analysis\",\n      \"pmids\": [\"28232469\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical step by which NOL3 restrains JAK-STAT not identified\", \"Whether splicing or apoptotic function underlies suppression unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Revealed how NOL3 expression is set transcriptionally, showing ATXN1L recruits HDAC3 to deacetylate histone H3 and repress the NOL3 promoter.\",\n      \"evidence\": \"ChIP, HDAC3 inhibition, ATXN1L knockout, immunofluorescence and Western blot\",\n      \"pmids\": [\"35414011\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cellular context where this regulation dominates not generalized\", \"Link between NOL3 repression and downstream phenotype not fully traced\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Connected NOL3 to ER-stress signaling by showing ELK1-induced NOL3 binds GRP78 to activate the PERK/CHOP UPR branch and promote proliferation/stemness in TP53-mutant cancer.\",\n      \"evidence\": \"Dual-luciferase reporter, co-IP, gain/loss-of-function studies, and xenografts\",\n      \"pmids\": [\"41864308\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis and domain mediating GRP78 binding not defined\", \"Reconciliation of pro-tumor UPR role with myeloid tumor-suppressor role not addressed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NOL3's splicing, anti-apoptotic, transcriptional-target, and UPR-modulating activities are integrated into one mechanistic model — and which isoform mediates each — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model linking isoform/domain to each function\", \"Direct molecular substrates/targets in apoptosis and JAK-STAT suppression unidentified\", \"Apparent context-dependent opposing roles (tumor suppressor vs pro-tumor) not mechanistically reconciled\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"SRp30c\", \"GRP78\", \"ATXN1L\", \"HDAC3\", \"ELK1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}