{"gene":"ZC3H15","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2009,"finding":"Dfrp1 (ZC3H15) forms a stable complex with the GTPase Drg1; complex formation specifically stabilizes at least one component, and the Drg1/Dfrp1 complex co-sediments with polysomes, placing it at translating ribosomes and implicating it in protein synthesis regulation.","method":"Co-sedimentation with polysome fractions, analysis of protein stability upon complex disruption in mammalian cells","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — polysome co-sedimentation and stability analyses in physiological conditions, single lab but two orthogonal methods","pmids":["19819225"],"is_preprint":false},{"year":2013,"finding":"ZC3H15 (LEREPO4) interacts with the signaling adapter TRAF-2 as demonstrated by co-immunoprecipitation, suggesting a functional role within the NF-κB pathway.","method":"Co-immunoprecipitation (Co-IP) in HeLa cells","journal":"International journal of oncology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP experiment, single lab, no functional epistasis or mechanistic follow-up confirming pathway placement","pmids":["23624947"],"is_preprint":false},{"year":2013,"finding":"ZC3H15 (Lerepo4) stimulates the GTPase activity of Drg1 approximately four-fold; the DFRP domain of Lerepo4 is solely responsible for this catalytic stimulation and for increasing Drg1 thermal stability, without changing Drg1 nucleotide affinity. Drg1 is a potassium-dependent GTPase, and the TGS domain of Drg1 mediates Lerepo4 action.","method":"Purified protein reconstitution, in vitro GTPase assays, domain-deletion and phosphomimicking mutagenesis, thermal stability assays","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with purified proteins, systematic mutagenesis of multiple Drg1 variants and domain dissection, multiple orthogonal functional readouts","pmids":["23711155"],"is_preprint":false},{"year":2013,"finding":"ZC3H15 (LEREPO4) shows mainly diffuse cytoplasmic distribution by immunofluorescence microscopy and western blotting of subcellular protein fractions in HeLa cells.","method":"Immunofluorescence microscopy and subcellular fractionation followed by western blotting","journal":"International journal of oncology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, localization established but not linked to a functional consequence","pmids":["23624947"],"is_preprint":false},{"year":2021,"finding":"In yeast, TMA46 (DFRP1/ZC3H15 ortholog) deletion alters translation elongation processivity and ribosome stalling/collision resolution, and genetically interacts with the SLH1/ASCC3 helicase component of the RQT complex, placing TMA46 in the ribosome-associated quality control pathway.","method":"Ribo-Seq and RNA-Seq of TMA46 knockout S. cerevisiae strains","journal":"F1000Research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ribosome profiling (Ribo-Seq) and RNA-Seq in deletion strains provide genome-wide translational readout; single lab, yeast ortholog","pmids":["34900236"],"is_preprint":false},{"year":2022,"finding":"ZC3H15 promotes EGFR protein stability in GBM cells by inhibiting transcription of CBL (an E3 ubiquitin ligase for EGFR), thereby reducing EGFR ubiquitination and proteasomal degradation; silencing CBL partially rescues the proliferation/migration defects caused by ZC3H15 knockdown.","method":"siRNA knockdown, ubiquitination assays, CBL transcription analysis, epistasis rescue experiment in GBM cells","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (ubiquitination assay, transcription analysis, genetic rescue), single lab","pmids":["35027542"],"is_preprint":false},{"year":2022,"finding":"ZC3H15 stabilizes c-Myc protein in gastric cancer cells by suppressing transcription of FBXW7, the E3 ubiquitin ligase responsible for c-Myc degradation; silencing FBXW7 in ZC3H15-knockdown cells partially rescues proliferation and migration.","method":"siRNA knockdown, protein stability assays, FBXW7 transcription analysis, genetic rescue experiment in gastric cancer cells","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple methods (stability assay, transcription analysis, epistasis rescue), single lab","pmids":["35064102"],"is_preprint":false},{"year":2025,"finding":"ZC3H15 interacts with TERT via its N-terminal domain in an RNA-dependent manner and associates with GEM nuclear bodies; deletion of ZC3H15 causes spatiotemporal fusion of GEMs and Cajal bodies, sequestering telomerase within Cajal bodies, reducing telomerase recruitment to telomeres during S phase, and leading to telomere shortening and cellular senescence despite increased telomerase activity.","method":"Genome-wide TriFC screen, proximity labeling (PhastID), Co-IP, live-cell imaging, telomerase activity assays, TERC precursor RNA accumulation analysis in HTC75 cells","journal":"Cell & bioscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (TriFC, PhastID, Co-IP, live imaging, functional readouts), single lab","pmids":["40696438"],"is_preprint":false},{"year":2025,"finding":"ZC3H15 maintains KEAP1 stability, thereby promoting NRF2 ubiquitination and degradation under oxidative stress; ZC3H15 knockdown activates the KEAP1/NRF2 pathway to reduce neuronal oxidative stress, and this effect requires NRF2.","method":"Immunoblotting, Co-IP, in vivo and in vitro ubiquitination assays, AAV-shRNA knockdown in mouse BCP model, NRF2 deletion rescue experiment","journal":"Neoplasia (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assays plus genetic rescue with NRF2 deletion, single lab, multiple orthogonal methods","pmids":["39908779"],"is_preprint":false},{"year":2025,"finding":"ZC3H15 also suppresses microglial inflammatory activation through the IκBα/NF-κB signaling pathway; AAV-shZC3H15 knockdown attenuates microglial activation in vivo and in LPS-treated microglial cells in vitro.","method":"AAV-shRNA knockdown in mouse BCP model, LPS-treated microglial cell assays, immunofluorescence and immunoblotting","journal":"Neoplasia (New York, N.Y.)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pathway placement based on knockdown with pathway marker readout but no direct binding or epistasis to IκBα","pmids":["39908779"],"is_preprint":false},{"year":2026,"finding":"ZC3H15 binds PTEN via its DFRP structural domain and recruits the E3 ubiquitin ligase TRIM56 to promote PTEN ubiquitination and degradation, activating AKT-mTOR signaling in NSCLC cells.","method":"Co-IP, domain-binding assays (DFRP domain), in vitro/cellular ubiquitination assays, overexpression and knockdown in NSCLC cells","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP with domain mapping, ubiquitination assays, and pathway readout; single lab, multiple orthogonal methods","pmids":["41513632"],"is_preprint":false}],"current_model":"ZC3H15 (DFRP1/LEREPO4) is a conserved eukaryotic protein that forms a stable complex with the GTPase DRG1 via its DFRP domain, stimulating DRG1's potassium-dependent GTPase activity ~4-fold and stabilizing the complex at translating polysomes to regulate protein synthesis; beyond translation, ZC3H15 regulates protein stability of multiple targets (EGFR, c-Myc, NRF2, PTEN) by modulating their ubiquitination — either by suppressing transcription of cognate E3 ligases (CBL, FBXW7) or by directly recruiting E3 ligases (TRIM56) — thereby activating oncogenic signaling (EGFR, AKT-mTOR), and it also controls telomerase spatial dynamics by anchoring it away from Cajal bodies to enable telomere elongation."},"narrative":{"mechanistic_narrative":"ZC3H15 (DFRP1/LEREPO4) is a conserved, predominantly cytoplasmic eukaryotic protein that functions both in translation and in the post-translational control of protein stability [PMID:19819225, PMID:23624947]. Through its DFRP domain it forms a stable complex with the potassium-dependent GTPase DRG1, stimulating DRG1 GTPase activity approximately four-fold and increasing its thermal stability without altering nucleotide affinity, with the TGS domain of DRG1 mediating this action [PMID:23711155]; the resulting complex co-sediments with polysomes, placing ZC3H15 at translating ribosomes [PMID:19819225]. Consistent with a translation-associated role, deletion of the yeast ortholog TMA46 perturbs elongation processivity and resolution of ribosome stalling/collisions and interacts genetically with the RQT helicase component SLH1/ASCC3 [PMID:34900236]. Independently, ZC3H15 governs the stability of multiple cancer-relevant proteins by tuning their ubiquitination: it suppresses transcription of the E3 ligases CBL and FBXW7 to stabilize EGFR and c-Myc respectively [PMID:35027542, PMID:35064102], directly binds PTEN via its DFRP domain and recruits the E3 ligase TRIM56 to drive PTEN degradation and AKT-mTOR activation [PMID:41513632], and maintains KEAP1 stability to promote NRF2 ubiquitination and degradation under oxidative stress [PMID:39908779]. ZC3H15 also binds TERT in an RNA-dependent manner and associates with GEM nuclear bodies, where it anchors telomerase away from Cajal bodies to enable telomere elongation, such that its loss sequesters telomerase in Cajal bodies and causes telomere shortening and senescence [PMID:40696438].","teleology":[{"year":2009,"claim":"Established that ZC3H15 is not a free-standing factor but a stable partner of the GTPase DRG1 acting at the translation machinery, framing its core biochemical role.","evidence":"Polysome co-sedimentation and complex-disruption stability analysis in mammalian cells","pmids":["19819225"],"confidence":"Medium","gaps":["Does not define which subunit is stabilized or the molecular basis of complex assembly","No direct readout of an effect on translation output"]},{"year":2013,"claim":"Defined the precise biochemical function of ZC3H15 as a DFRP-domain-dependent activator of DRG1 GTPase activity and stabilizer, resolving how it acts on its partner.","evidence":"Purified-protein reconstitution, in vitro GTPase and thermal stability assays, domain-deletion and phosphomimicking mutagenesis","pmids":["23711155"],"confidence":"High","gaps":["The downstream consequence of GTPase stimulation for ribosome function not directly measured","Physiological regulation of the interaction (e.g. phosphorylation) not established in cells"]},{"year":2013,"claim":"Placed ZC3H15 in the cytoplasm and linked it to TRAF-2/NF-κB signaling, raising a non-translational signaling role.","evidence":"Immunofluorescence, subcellular fractionation, and Co-IP in HeLa cells","pmids":["23624947"],"confidence":"Low","gaps":["TRAF-2 interaction rests on a single Co-IP without reciprocal validation or functional epistasis","Localization not tied to a functional consequence"]},{"year":2021,"claim":"Connected the DRG1-partner function to a concrete translational phenotype, implicating ZC3H15/TMA46 in ribosome-associated quality control rather than bulk translation alone.","evidence":"Ribo-Seq and RNA-Seq of TMA46 knockout S. cerevisiae","pmids":["34900236"],"confidence":"Medium","gaps":["Mechanistic link to the RQT complex is genetic, not biochemical","Conservation of this RQC role to the human protein not demonstrated"]},{"year":2022,"claim":"Revealed a second, transcription-linked mode of action whereby ZC3H15 stabilizes oncoproteins (EGFR, c-Myc) by repressing transcription of their cognate E3 ligases (CBL, FBXW7).","evidence":"siRNA knockdown, ubiquitination/stability assays, E3-ligase transcription analysis, and epistasis rescue in GBM and gastric cancer cells","pmids":["35027542","35064102"],"confidence":"Medium","gaps":["Mechanism by which ZC3H15 represses CBL/FBXW7 transcription is unknown","Whether ZC3H15 acts directly on chromatin or transcription factors not addressed"]},{"year":2025,"claim":"Showed ZC3H15 directly modulates the ubiquitination of stress and tumor-suppressor proteins, stabilizing KEAP1 to promote NRF2 degradation under oxidative stress.","evidence":"Co-IP, in vivo/in vitro ubiquitination assays, AAV-shRNA knockdown in a mouse BCP model with NRF2-deletion rescue","pmids":["39908779"],"confidence":"Medium","gaps":["Whether ZC3H15 binds KEAP1 directly or via an intermediary not resolved","Relationship between this KEAP1/NRF2 role and the DRG1-translation function unclear"]},{"year":2025,"claim":"Identified a nuclear, RNA-dependent role for ZC3H15 in telomere maintenance through spatial control of telomerase between GEM and Cajal bodies.","evidence":"Genome-wide TriFC screen, PhastID proximity labeling, Co-IP, live-cell imaging, and telomerase activity assays in HTC75 cells","pmids":["40696438"],"confidence":"Medium","gaps":["How a largely cytoplasmic protein partitions to nuclear bodies is unexplained","The RNA mediating the TERT interaction is not identified"]},{"year":2026,"claim":"Demonstrated that ZC3H15 can directly recruit an E3 ligase rather than only repress one, binding PTEN via its DFRP domain and recruiting TRIM56 to activate AKT-mTOR.","evidence":"Co-IP, DFRP domain-binding assays, ubiquitination assays, and knockdown/overexpression in NSCLC cells","pmids":["41513632"],"confidence":"Medium","gaps":["Whether DFRP domain binding to PTEN competes with its DRG1 binding is untested","Generality of the TRIM56-recruitment mechanism to other substrates unknown"]},{"year":null,"claim":"It remains unknown how ZC3H15's conserved DRG1/translation function mechanistically connects to its diverse roles in oncoprotein ubiquitination and telomerase spatial control, and whether these represent one integrated mechanism or independent activities.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying biochemical model links the DFRP-DRG1 axis to E3-ligase modulation","Whether the ubiquitination phenotypes are downstream of altered translation has not been tested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[2]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[7]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[10]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,3]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[7]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,4]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[5,6,8,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5,10]}],"complexes":["DRG1/ZC3H15 (DRG1/DFRP1) complex"],"partners":["DRG1","TERT","PTEN","TRIM56","KEAP1","TRAF2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8WU90","full_name":"Zinc finger CCCH domain-containing protein 15","aliases":["DRG family-regulatory protein 1","Likely ortholog of mouse immediate early response erythropoietin 4"],"length_aa":426,"mass_kda":48.6,"function":"Protects DRG1 from proteolytic degradation (PubMed:19819225). Stimulates DRG1 GTPase activity likely by increasing the affinity for the potassium ions (PubMed:23711155)","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q8WU90/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ZC3H15","classification":"Not Classified","n_dependent_lines":16,"n_total_lines":1208,"dependency_fraction":0.013245033112582781},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DRG1","stoichiometry":10.0},{"gene":"CAPZB","stoichiometry":0.2},{"gene":"CCT6A","stoichiometry":0.2},{"gene":"G3BP2","stoichiometry":0.2},{"gene":"NPM1","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"RACK1","stoichiometry":0.2},{"gene":"RBM42","stoichiometry":0.2},{"gene":"RBM8A","stoichiometry":0.2},{"gene":"RPS16","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/ZC3H15","total_profiled":1310},"omim":[{"mim_id":"620641","title":"TAN-ALMURSHEDI SYNDROME; TANALS","url":"https://www.omim.org/entry/620641"},{"mim_id":"619704","title":"ZINC FINGER CCCH DOMAIN-CONTAINING PROTEIN 15; ZC3H15","url":"https://www.omim.org/entry/619704"},{"mim_id":"603952","title":"DEVELOPMENTALLY REGULATED GTP-BINDING PROTEIN 1; DRG1","url":"https://www.omim.org/entry/603952"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Cytosol","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ZC3H15"},"hgnc":{"alias_symbol":["DFRP1","LEREPO4"],"prev_symbol":[]},"alphafold":{"accession":"Q8WU90","domains":[{"cath_id":"-","chopping":"13-86","consensus_level":"medium","plddt":83.5115,"start":13,"end":86},{"cath_id":"-","chopping":"93-131","consensus_level":"medium","plddt":79.8705,"start":93,"end":131},{"cath_id":"-","chopping":"137-166_173-230","consensus_level":"medium","plddt":77.0149,"start":137,"end":230},{"cath_id":"-","chopping":"253-303","consensus_level":"high","plddt":83.548,"start":253,"end":303}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WU90","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WU90-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WU90-F1-predicted_aligned_error_v6.png","plddt_mean":71.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ZC3H15","jax_strain_url":"https://www.jax.org/strain/search?query=ZC3H15"},"sequence":{"accession":"Q8WU90","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WU90.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WU90/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WU90"}},"corpus_meta":[{"pmid":"19819225","id":"PMC_19819225","title":"Independent stabilizations of polysomal Drg1/Dfrp1 complex and non-polysomal Drg2/Dfrp2 complex in mammalian cells.","date":"2009","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/19819225","citation_count":24,"is_preprint":false},{"pmid":"35027542","id":"PMC_35027542","title":"ZC3H15 promotes glioblastoma progression through regulating EGFR stability.","date":"2022","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/35027542","citation_count":22,"is_preprint":false},{"pmid":"35064102","id":"PMC_35064102","title":"ZC3H15 promotes gastric cancer progression by targeting the FBXW7/c-Myc pathway.","date":"2022","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/35064102","citation_count":19,"is_preprint":false},{"pmid":"23624947","id":"PMC_23624947","title":"Characterization of ZC3H15 as a potential TRAF-2-interacting protein implicated in the NFκB pathway and overexpressed in AML.","date":"2013","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/23624947","citation_count":15,"is_preprint":false},{"pmid":"23711155","id":"PMC_23711155","title":"Human Drg1 is a potassium-dependent GTPase enhanced by Lerepo4.","date":"2013","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/23711155","citation_count":15,"is_preprint":false},{"pmid":"20925576","id":"PMC_20925576","title":"Inhibition of X4-tropic HIV type 1 replication by knockdown of the cellular protein LEREPO4.","date":"2010","source":"AIDS research and human retroviruses","url":"https://pubmed.ncbi.nlm.nih.gov/20925576","citation_count":5,"is_preprint":false},{"pmid":"39908779","id":"PMC_39908779","title":"ZC3H15 suppression ameliorates bone cancer pain through inhibiting neuronal oxidative stress and microglial inflammation.","date":"2025","source":"Neoplasia (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/39908779","citation_count":3,"is_preprint":false},{"pmid":"34900236","id":"PMC_34900236","title":"Ribo-Seq and RNA-Seq of TMA46 ( DFRP1) and GIR2 ( DFRP2) knockout yeast strains.","date":"2021","source":"F1000Research","url":"https://pubmed.ncbi.nlm.nih.gov/34900236","citation_count":2,"is_preprint":false},{"pmid":"40696438","id":"PMC_40696438","title":"Disruption of ZC3H15 compromises telomere length maintenance by entrapping telomerase within cajal bodies.","date":"2025","source":"Cell & bioscience","url":"https://pubmed.ncbi.nlm.nih.gov/40696438","citation_count":1,"is_preprint":false},{"pmid":"41513632","id":"PMC_41513632","title":"ZC3H15 regulates the ubiquitination of PTEN via recruitment of TRIM56 and promotes malignant progression of non-small cell lung cancer.","date":"2026","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/41513632","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7136,"output_tokens":2685,"usd":0.030842,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9927,"output_tokens":3120,"usd":0.063817,"stage2_stop_reason":"end_turn"},"total_usd":0.094659,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2009,\n      \"finding\": \"Dfrp1 (ZC3H15) forms a stable complex with the GTPase Drg1; complex formation specifically stabilizes at least one component, and the Drg1/Dfrp1 complex co-sediments with polysomes, placing it at translating ribosomes and implicating it in protein synthesis regulation.\",\n      \"method\": \"Co-sedimentation with polysome fractions, analysis of protein stability upon complex disruption in mammalian cells\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — polysome co-sedimentation and stability analyses in physiological conditions, single lab but two orthogonal methods\",\n      \"pmids\": [\"19819225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ZC3H15 (LEREPO4) interacts with the signaling adapter TRAF-2 as demonstrated by co-immunoprecipitation, suggesting a functional role within the NF-κB pathway.\",\n      \"method\": \"Co-immunoprecipitation (Co-IP) in HeLa cells\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP experiment, single lab, no functional epistasis or mechanistic follow-up confirming pathway placement\",\n      \"pmids\": [\"23624947\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ZC3H15 (Lerepo4) stimulates the GTPase activity of Drg1 approximately four-fold; the DFRP domain of Lerepo4 is solely responsible for this catalytic stimulation and for increasing Drg1 thermal stability, without changing Drg1 nucleotide affinity. Drg1 is a potassium-dependent GTPase, and the TGS domain of Drg1 mediates Lerepo4 action.\",\n      \"method\": \"Purified protein reconstitution, in vitro GTPase assays, domain-deletion and phosphomimicking mutagenesis, thermal stability assays\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with purified proteins, systematic mutagenesis of multiple Drg1 variants and domain dissection, multiple orthogonal functional readouts\",\n      \"pmids\": [\"23711155\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ZC3H15 (LEREPO4) shows mainly diffuse cytoplasmic distribution by immunofluorescence microscopy and western blotting of subcellular protein fractions in HeLa cells.\",\n      \"method\": \"Immunofluorescence microscopy and subcellular fractionation followed by western blotting\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, localization established but not linked to a functional consequence\",\n      \"pmids\": [\"23624947\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In yeast, TMA46 (DFRP1/ZC3H15 ortholog) deletion alters translation elongation processivity and ribosome stalling/collision resolution, and genetically interacts with the SLH1/ASCC3 helicase component of the RQT complex, placing TMA46 in the ribosome-associated quality control pathway.\",\n      \"method\": \"Ribo-Seq and RNA-Seq of TMA46 knockout S. cerevisiae strains\",\n      \"journal\": \"F1000Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ribosome profiling (Ribo-Seq) and RNA-Seq in deletion strains provide genome-wide translational readout; single lab, yeast ortholog\",\n      \"pmids\": [\"34900236\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ZC3H15 promotes EGFR protein stability in GBM cells by inhibiting transcription of CBL (an E3 ubiquitin ligase for EGFR), thereby reducing EGFR ubiquitination and proteasomal degradation; silencing CBL partially rescues the proliferation/migration defects caused by ZC3H15 knockdown.\",\n      \"method\": \"siRNA knockdown, ubiquitination assays, CBL transcription analysis, epistasis rescue experiment in GBM cells\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (ubiquitination assay, transcription analysis, genetic rescue), single lab\",\n      \"pmids\": [\"35027542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ZC3H15 stabilizes c-Myc protein in gastric cancer cells by suppressing transcription of FBXW7, the E3 ubiquitin ligase responsible for c-Myc degradation; silencing FBXW7 in ZC3H15-knockdown cells partially rescues proliferation and migration.\",\n      \"method\": \"siRNA knockdown, protein stability assays, FBXW7 transcription analysis, genetic rescue experiment in gastric cancer cells\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple methods (stability assay, transcription analysis, epistasis rescue), single lab\",\n      \"pmids\": [\"35064102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ZC3H15 interacts with TERT via its N-terminal domain in an RNA-dependent manner and associates with GEM nuclear bodies; deletion of ZC3H15 causes spatiotemporal fusion of GEMs and Cajal bodies, sequestering telomerase within Cajal bodies, reducing telomerase recruitment to telomeres during S phase, and leading to telomere shortening and cellular senescence despite increased telomerase activity.\",\n      \"method\": \"Genome-wide TriFC screen, proximity labeling (PhastID), Co-IP, live-cell imaging, telomerase activity assays, TERC precursor RNA accumulation analysis in HTC75 cells\",\n      \"journal\": \"Cell & bioscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (TriFC, PhastID, Co-IP, live imaging, functional readouts), single lab\",\n      \"pmids\": [\"40696438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ZC3H15 maintains KEAP1 stability, thereby promoting NRF2 ubiquitination and degradation under oxidative stress; ZC3H15 knockdown activates the KEAP1/NRF2 pathway to reduce neuronal oxidative stress, and this effect requires NRF2.\",\n      \"method\": \"Immunoblotting, Co-IP, in vivo and in vitro ubiquitination assays, AAV-shRNA knockdown in mouse BCP model, NRF2 deletion rescue experiment\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assays plus genetic rescue with NRF2 deletion, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"39908779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ZC3H15 also suppresses microglial inflammatory activation through the IκBα/NF-κB signaling pathway; AAV-shZC3H15 knockdown attenuates microglial activation in vivo and in LPS-treated microglial cells in vitro.\",\n      \"method\": \"AAV-shRNA knockdown in mouse BCP model, LPS-treated microglial cell assays, immunofluorescence and immunoblotting\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pathway placement based on knockdown with pathway marker readout but no direct binding or epistasis to IκBα\",\n      \"pmids\": [\"39908779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ZC3H15 binds PTEN via its DFRP structural domain and recruits the E3 ubiquitin ligase TRIM56 to promote PTEN ubiquitination and degradation, activating AKT-mTOR signaling in NSCLC cells.\",\n      \"method\": \"Co-IP, domain-binding assays (DFRP domain), in vitro/cellular ubiquitination assays, overexpression and knockdown in NSCLC cells\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP with domain mapping, ubiquitination assays, and pathway readout; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"41513632\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ZC3H15 (DFRP1/LEREPO4) is a conserved eukaryotic protein that forms a stable complex with the GTPase DRG1 via its DFRP domain, stimulating DRG1's potassium-dependent GTPase activity ~4-fold and stabilizing the complex at translating polysomes to regulate protein synthesis; beyond translation, ZC3H15 regulates protein stability of multiple targets (EGFR, c-Myc, NRF2, PTEN) by modulating their ubiquitination — either by suppressing transcription of cognate E3 ligases (CBL, FBXW7) or by directly recruiting E3 ligases (TRIM56) — thereby activating oncogenic signaling (EGFR, AKT-mTOR), and it also controls telomerase spatial dynamics by anchoring it away from Cajal bodies to enable telomere elongation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ZC3H15 (DFRP1/LEREPO4) is a conserved, predominantly cytoplasmic eukaryotic protein that functions both in translation and in the post-translational control of protein stability [#0, #3]. Through its DFRP domain it forms a stable complex with the potassium-dependent GTPase DRG1, stimulating DRG1 GTPase activity approximately four-fold and increasing its thermal stability without altering nucleotide affinity, with the TGS domain of DRG1 mediating this action [#2]; the resulting complex co-sediments with polysomes, placing ZC3H15 at translating ribosomes [#0]. Consistent with a translation-associated role, deletion of the yeast ortholog TMA46 perturbs elongation processivity and resolution of ribosome stalling/collisions and interacts genetically with the RQT helicase component SLH1/ASCC3 [#4]. Independently, ZC3H15 governs the stability of multiple cancer-relevant proteins by tuning their ubiquitination: it suppresses transcription of the E3 ligases CBL and FBXW7 to stabilize EGFR and c-Myc respectively [#5, #6], directly binds PTEN via its DFRP domain and recruits the E3 ligase TRIM56 to drive PTEN degradation and AKT-mTOR activation [#10], and maintains KEAP1 stability to promote NRF2 ubiquitination and degradation under oxidative stress [#8]. ZC3H15 also binds TERT in an RNA-dependent manner and associates with GEM nuclear bodies, where it anchors telomerase away from Cajal bodies to enable telomere elongation, such that its loss sequesters telomerase in Cajal bodies and causes telomere shortening and senescence [#7].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established that ZC3H15 is not a free-standing factor but a stable partner of the GTPase DRG1 acting at the translation machinery, framing its core biochemical role.\",\n      \"evidence\": \"Polysome co-sedimentation and complex-disruption stability analysis in mammalian cells\",\n      \"pmids\": [\"19819225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not define which subunit is stabilized or the molecular basis of complex assembly\", \"No direct readout of an effect on translation output\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined the precise biochemical function of ZC3H15 as a DFRP-domain-dependent activator of DRG1 GTPase activity and stabilizer, resolving how it acts on its partner.\",\n      \"evidence\": \"Purified-protein reconstitution, in vitro GTPase and thermal stability assays, domain-deletion and phosphomimicking mutagenesis\",\n      \"pmids\": [\"23711155\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The downstream consequence of GTPase stimulation for ribosome function not directly measured\", \"Physiological regulation of the interaction (e.g. phosphorylation) not established in cells\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Placed ZC3H15 in the cytoplasm and linked it to TRAF-2/NF-\\u03baB signaling, raising a non-translational signaling role.\",\n      \"evidence\": \"Immunofluorescence, subcellular fractionation, and Co-IP in HeLa cells\",\n      \"pmids\": [\"23624947\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"TRAF-2 interaction rests on a single Co-IP without reciprocal validation or functional epistasis\", \"Localization not tied to a functional consequence\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected the DRG1-partner function to a concrete translational phenotype, implicating ZC3H15/TMA46 in ribosome-associated quality control rather than bulk translation alone.\",\n      \"evidence\": \"Ribo-Seq and RNA-Seq of TMA46 knockout S. cerevisiae\",\n      \"pmids\": [\"34900236\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link to the RQT complex is genetic, not biochemical\", \"Conservation of this RQC role to the human protein not demonstrated\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Revealed a second, transcription-linked mode of action whereby ZC3H15 stabilizes oncoproteins (EGFR, c-Myc) by repressing transcription of their cognate E3 ligases (CBL, FBXW7).\",\n      \"evidence\": \"siRNA knockdown, ubiquitination/stability assays, E3-ligase transcription analysis, and epistasis rescue in GBM and gastric cancer cells\",\n      \"pmids\": [\"35027542\", \"35064102\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which ZC3H15 represses CBL/FBXW7 transcription is unknown\", \"Whether ZC3H15 acts directly on chromatin or transcription factors not addressed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed ZC3H15 directly modulates the ubiquitination of stress and tumor-suppressor proteins, stabilizing KEAP1 to promote NRF2 degradation under oxidative stress.\",\n      \"evidence\": \"Co-IP, in vivo/in vitro ubiquitination assays, AAV-shRNA knockdown in a mouse BCP model with NRF2-deletion rescue\",\n      \"pmids\": [\"39908779\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ZC3H15 binds KEAP1 directly or via an intermediary not resolved\", \"Relationship between this KEAP1/NRF2 role and the DRG1-translation function unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified a nuclear, RNA-dependent role for ZC3H15 in telomere maintenance through spatial control of telomerase between GEM and Cajal bodies.\",\n      \"evidence\": \"Genome-wide TriFC screen, PhastID proximity labeling, Co-IP, live-cell imaging, and telomerase activity assays in HTC75 cells\",\n      \"pmids\": [\"40696438\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How a largely cytoplasmic protein partitions to nuclear bodies is unexplained\", \"The RNA mediating the TERT interaction is not identified\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Demonstrated that ZC3H15 can directly recruit an E3 ligase rather than only repress one, binding PTEN via its DFRP domain and recruiting TRIM56 to activate AKT-mTOR.\",\n      \"evidence\": \"Co-IP, DFRP domain-binding assays, ubiquitination assays, and knockdown/overexpression in NSCLC cells\",\n      \"pmids\": [\"41513632\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether DFRP domain binding to PTEN competes with its DRG1 binding is untested\", \"Generality of the TRIM56-recruitment mechanism to other substrates unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how ZC3H15's conserved DRG1/translation function mechanistically connects to its diverse roles in oncoprotein ubiquitination and telomerase spatial control, and whether these represent one integrated mechanism or independent activities.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying biochemical model links the DFRP-DRG1 axis to E3-ligase modulation\", \"Whether the ubiquitination phenotypes are downstream of altered translation has not been tested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 4]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [5, 6, 8, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 10]}\n    ],\n    \"complexes\": [\"DRG1/ZC3H15 (DRG1/DFRP1) complex\"],\n    \"partners\": [\"DRG1\", \"TERT\", \"PTEN\", \"TRIM56\", \"KEAP1\", \"TRAF2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}