{"gene":"CNIH4","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2014,"finding":"CNIH4 (human cornichon homologue 4) localizes in the early secretory pathway (ER) and interacts with members of the Class 3 family of GPCRs. Both overexpression and knockdown of CNIH4 cause intracellular retention of GPCRs, demonstrating it is required at an optimal level for GPCR export. Low-level overexpression of CNIH4 rescued cell surface expression of an intracellularly retained mutant β2-adrenergic receptor. Co-immunoprecipitation of CNIH4 with Sec23 and Sec24, components of the COPII coat complex, indicates CNIH4 acts as a cargo-sorting receptor recruiting GPCRs into COPII vesicles for ER export.","method":"BRET-based proteomic screen, co-immunoprecipitation, knockdown/overexpression with cell-surface trafficking assays, fluorescence microscopy localization","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP with COPII components, BRET-based interaction screen, gain- and loss-of-function with defined trafficking phenotype, rescue experiment, multiple orthogonal methods in a single focused study","pmids":["24405750"],"is_preprint":false},{"year":2019,"finding":"CNIH4 is a downstream effector in a TMED9-dependent pathway that promotes colon cancer metastasis. TMED9 knockdown compromises TGFα biogenesis and secretion; CNIH4, as a member of the CORNICHON family of TGFα exporters, is part of a positive feedback loop involving TMED9, TGFα, and GLI1 that enhances metastatic behavior. CNIH4 expression is regulated downstream of TMED9/TMED3 antagonism.","method":"RNAi knockdown, functional rescue (migration assay), transcriptional profiling, epistasis analysis in colon cancer cell lines","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis via knockdown/rescue, multiple cell types tested, but mechanistic role of CNIH4 itself in TGFα export inferred rather than directly reconstituted","pmids":["31253868"],"is_preprint":false},{"year":2023,"finding":"CNIH4 inhibits ferroptosis in human cervical cancer cells by upregulating SLC7A11, which increases cystine import, elevates intracellular glutathione synthesis, and enhances glutathione peroxidase 4 (GPX4) activity. Silencing SLC7A11 abolished CNIH4-mediated inhibition of ferroptosis, placing SLC7A11 downstream of CNIH4 in this pathway.","method":"Lentiviral gain- and loss-of-function, cell viability assays, ferroptosis assays, transcriptome sequencing, SLC7A11 knockdown epistasis","journal":"Chemico-biological interactions","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain- and loss-of-function with epistasis (SLC7A11 KD rescue), transcriptomics validation, single lab, no in vitro reconstitution of the CNIH4–SLC7A11 regulatory step","pmids":["37716418"],"is_preprint":false},{"year":2023,"finding":"Cnih4 knockout mice (Cnih4tm1a-/-) are fertile, with only slight reductions in sperm count, morphology, and motility compared to wild-type. Testicular histology and ovarian folliculogenesis are normal. Compensatory upregulation of Cnih3 was detected in knockout mice, suggesting functional redundancy within the cornichon family for gametogenesis.","method":"Genetic knockout (LacZ reporter insertion), Western blot, immunofluorescence, computer-aided sperm analysis, histology, fertility testing over six months","journal":"Developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic knockout with multiple phenotypic readouts and compensatory mechanism identified; negative finding for essential fertility role is well-supported","pmids":["36657507"],"is_preprint":false},{"year":2025,"finding":"CircUCK2(2,3) sponges miR-149-5p to increase CNIH4 protein levels, which in turn amplifies TGFα secretion, leading to activation of EGFR and downstream pAKT and pERK signaling in hepatocellular carcinoma cells. CRISPR-Cas9 disruption and medium transfer assays confirmed the pathway order: circUCK2(2,3) → miR-149-5p suppression → CNIH4 upregulation → TGFα secretion → EGFR activation.","method":"RNA immunoprecipitation (RIP), RNA pulldown, CRISPR-Cas9, polysome fractionation, dual luciferase reporter, medium transfer assay, gain- and loss-of-function","journal":"Cellular & molecular biology letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods establishing pathway order, single lab, CNIH4's direct role in TGFα secretion consistent with prior GPCR trafficking function but not independently reconstituted here","pmids":["39885395"],"is_preprint":false},{"year":2026,"finding":"In oral squamous cell carcinoma, the transcription factor FOXM1 directly binds the CNIH4 enhancer (validated by ChIP-qPCR for H3K27ac and FOXM1 enrichment) to activate CNIH4 transcription. M2 macrophage-derived glutamine, taken up via SLC38A5, enhances FOXM1 recruitment to the CNIH4 enhancer and upregulates CNIH4 expression. CNIH4 overexpression rescued proliferation and invasion impaired by FOXM1 knockdown, placing CNIH4 downstream of FOXM1 in this axis.","method":"ChIP-qPCR (H3K27ac and FOXM1), SLC38A5 knockdown, conditioned medium transfer, CCK-8 proliferation assay, Transwell invasion assay, FOXM1 knockdown rescue by CNIH4 overexpression","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct ChIP-qPCR validation of FOXM1 binding to CNIH4 enhancer plus epistasis rescue experiment; single lab, no independent replication","pmids":["41715179"],"is_preprint":false}],"current_model":"CNIH4 is an ER-resident transmembrane cargo-sorting receptor that interacts with GPCRs and COPII coat components (Sec23/Sec24) to facilitate ER-to-Golgi export of GPCRs and TGFα-family ligands; in cancer contexts it additionally suppresses ferroptosis by upregulating SLC7A11-mediated cystine import and is transcriptionally activated by FOXM1 in response to metabolic signals, while its expression is post-transcriptionally amplified via a miR-149-5p sponge mechanism that feeds into EGFR/AKT/ERK signaling."},"narrative":{"mechanistic_narrative":"CNIH4 is an ER-resident cargo-sorting receptor that couples transmembrane cargo to the COPII machinery for ER-to-Golgi export [PMID:24405750]. It localizes to the early secretory pathway, binds Class 3 GPCRs, and co-immunoprecipitates with the COPII coat components Sec23 and Sec24, recruiting GPCRs into COPII vesicles; both overexpression and knockdown cause intracellular receptor retention, and low-level CNIH4 rescues surface expression of a trafficking-defective β2-adrenergic receptor, indicating that an optimal CNIH4 level is required for export [PMID:24405750]. As a member of the cornichon family, CNIH4 also functions in the biogenesis and secretion of the EGFR ligand TGFα, acting within a TMED9-dependent loop that promotes colon cancer metastasis [PMID:31253868] and amplifying TGFα secretion to drive EGFR–AKT–ERK signaling in hepatocellular carcinoma [PMID:39885395]. Across cancer contexts CNIH4 is a transcriptional and post-transcriptional node: FOXM1 directly binds the CNIH4 enhancer to activate its transcription in response to macrophage-derived glutamine in oral squamous cell carcinoma [PMID:41715179], its protein levels are raised by a circUCK2-driven miR-149-5p sponge [PMID:39885395], and it suppresses ferroptosis in cervical cancer by upregulating SLC7A11 to boost cystine import, glutathione synthesis, and GPX4 activity [PMID:37716418]. CNIH4 is dispensable for fertility in mice, where loss is buffered by compensatory upregulation of Cnih3 [PMID:36657507].","teleology":[{"year":2014,"claim":"Established CNIH4's core molecular function: whether the cornichon homologue acts in cargo export was unknown, and this work showed it is an ER cargo-sorting receptor linking GPCRs to the COPII coat.","evidence":"BRET interaction screen, reciprocal Co-IP with Sec23/Sec24, knockdown/overexpression trafficking assays and mutant receptor rescue in cultured cells","pmids":["24405750"],"confidence":"High","gaps":["No structure of the CNIH4–cargo or CNIH4–COPII interface","Cargo selectivity beyond Class 3 GPCRs not defined","Stoichiometry and regulation of the optimal expression level unresolved"]},{"year":2019,"claim":"Extended CNIH4's cargo repertoire to TGFα and linked it to disease: it was unclear whether CNIH4 contributes to growth-factor secretion, and epistasis placed it in a TMED9/TGFα/GLI1 feedback loop driving colon cancer metastasis.","evidence":"RNAi knockdown, migration rescue and transcriptional/epistasis analysis in colon cancer cell lines","pmids":["31253868"],"confidence":"Medium","gaps":["CNIH4's direct role in TGFα export inferred, not biochemically reconstituted","Mechanism of TMED9/TMED3 antagonism on CNIH4 unclear","Relationship between TGFα export and the COPII function from 2014 not directly connected"]},{"year":2023,"claim":"Defined a redox/metabolic role: whether CNIH4 influences cell death was unknown, and this work showed it suppresses ferroptosis through SLC7A11-dependent cystine import.","evidence":"Lentiviral gain/loss-of-function, ferroptosis and viability assays, transcriptomics and SLC7A11 knockdown epistasis in cervical cancer cells","pmids":["37716418"],"confidence":"Medium","gaps":["No reconstitution of how CNIH4 regulates SLC7A11","Unclear whether the effect requires CNIH4 trafficking activity","Single lab, single cancer context"]},{"year":2023,"claim":"Tested physiological essentiality: it was unknown whether CNIH4 is required in vivo, and a knockout showed it is dispensable for fertility owing to cornichon-family redundancy.","evidence":"Cnih4 knockout mice with histology, sperm analysis, fertility testing and detection of compensatory Cnih3 upregulation","pmids":["36657507"],"confidence":"Medium","gaps":["Phenotypes outside the reproductive system not examined","Extent of Cnih3 functional substitution not quantified at the molecular level","No tissue-specific or compound knockout"]},{"year":2025,"claim":"Resolved post-transcriptional control of CNIH4: it was unclear how CNIH4 levels are elevated in tumors, and a circUCK2/miR-149-5p sponge axis was shown to raise CNIH4 and feed TGFα–EGFR–AKT/ERK signaling.","evidence":"RIP, RNA pulldown, dual luciferase, CRISPR-Cas9, polysome fractionation and medium transfer in hepatocellular carcinoma cells","pmids":["39885395"],"confidence":"Medium","gaps":["CNIH4's direct TGFα-secretion step not reconstituted here","Generality of the circUCK2 axis beyond HCC unknown","Quantitative contribution of CNIH4 versus other miR-149-5p targets unclear"]},{"year":2026,"claim":"Resolved transcriptional control of CNIH4: how CNIH4 is induced by the tumor microenvironment was unknown, and FOXM1 was shown to bind the CNIH4 enhancer in response to macrophage-derived glutamine.","evidence":"ChIP-qPCR for FOXM1 and H3K27ac, SLC38A5 knockdown, conditioned-medium transfer and FOXM1-knockdown rescue by CNIH4 in oral squamous cell carcinoma","pmids":["41715179"],"confidence":"Medium","gaps":["Whether glutamine acts solely through FOXM1 is not established","Connection between FOXM1-driven CNIH4 and its trafficking/secretory output not shown","Single lab, no independent replication"]},{"year":null,"claim":"How CNIH4's biochemical cargo-export activity mechanistically connects to its downstream effects on TGFα/EGFR signaling, ferroptosis suppression via SLC7A11, and metastasis remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No reconstitution linking COPII-dependent cargo sorting to the cancer phenotypes","Whether SLC7A11 is a trafficking cargo of CNIH4 untested","No structural basis for cargo selectivity"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[0]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0]}],"complexes":[],"partners":["SEC23","SEC24","TMED9"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9P003","full_name":"Protein cornichon homolog 4","aliases":["Cornichon family AMPA receptor auxiliary protein 4"],"length_aa":139,"mass_kda":16.1,"function":"Involved in G protein-coupled receptors (GPCRs) trafficking from the endoplasmic reticulum to the cell surface; it promotes the exit of GPCRs from the early secretory pathway, likely through interaction with the COPII machinery (PubMed:24405750)","subcellular_location":"Membrane; Endoplasmic reticulum; Endoplasmic reticulum-Golgi intermediate compartment","url":"https://www.uniprot.org/uniprotkb/Q9P003/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/CNIH4","classification":"Common Essential","n_dependent_lines":681,"n_total_lines":1208,"dependency_fraction":0.5637417218543046},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CCDC47","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/CNIH4","total_profiled":1310},"omim":[{"mim_id":"617483","title":"CORNICHON FAMILY AMPA RECEPTOR AUXILIARY PROTEIN 4; CNIH4","url":"https://www.omim.org/entry/617483"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CNIH4"},"hgnc":{"alias_symbol":["HSPC163"],"prev_symbol":[]},"alphafold":{"accession":"Q9P003","domains":[{"cath_id":"1.20.120","chopping":"1-139","consensus_level":"medium","plddt":92.0693,"start":1,"end":139}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9P003","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9P003-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9P003-F1-predicted_aligned_error_v6.png","plddt_mean":92.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CNIH4","jax_strain_url":"https://www.jax.org/strain/search?query=CNIH4"},"sequence":{"accession":"Q9P003","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9P003.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9P003/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9P003"}},"corpus_meta":[{"pmid":"36404537","id":"PMC_36404537","title":"Potential roles of Cornichon Family AMPA Receptor Auxiliary Protein 4 (CNIH4) in head and neck squamous cell carcinoma.","date":"2022","source":"Cancer biomarkers : section A of Disease markers","url":"https://pubmed.ncbi.nlm.nih.gov/36404537","citation_count":82,"is_preprint":false},{"pmid":"24405750","id":"PMC_24405750","title":"CNIH4 interacts with newly synthesized GPCR and controls their export from the endoplasmic reticulum.","date":"2014","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/24405750","citation_count":53,"is_preprint":false},{"pmid":"31253868","id":"PMC_31253868","title":"The protein secretion modulator TMED9 drives CNIH4/TGFα/GLI signaling opposing TMED3-WNT-TCF to promote colon cancer metastases.","date":"2019","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/31253868","citation_count":49,"is_preprint":false},{"pmid":"36220450","id":"PMC_36220450","title":"Screening and identification of CNIH4 gene associated with cell proliferation in gastric cancer based on a large-scale CRISPR-Cas9 screening database DepMap.","date":"2022","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/36220450","citation_count":16,"is_preprint":false},{"pmid":"37716418","id":"PMC_37716418","title":"CNIH4 governs cervical cancer progression through reducing ferroptosis.","date":"2023","source":"Chemico-biological interactions","url":"https://pubmed.ncbi.nlm.nih.gov/37716418","citation_count":9,"is_preprint":false},{"pmid":"37062068","id":"PMC_37062068","title":"Integrated analysis based on vesicle trafficking-related genes identifying CNIH4 as a novel therapeutic target for glioma.","date":"2023","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37062068","citation_count":8,"is_preprint":false},{"pmid":"36657507","id":"PMC_36657507","title":"Cornichon protein CNIH4 is not essential for mice gametogenesis and fertility.","date":"2023","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/36657507","citation_count":4,"is_preprint":false},{"pmid":"39885395","id":"PMC_39885395","title":"CircUCK2(2,3) promotes cancer progression and enhances synergistic cytotoxicity of lenvatinib with EGFR inhibitors via activating CNIH4-TGFα-EGFR signaling.","date":"2025","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/39885395","citation_count":2,"is_preprint":false},{"pmid":"40051704","id":"PMC_40051704","title":"Deciphering the role of CNIH4 in pan-cancer landscapes and its significance in breast cancer progression.","date":"2025","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40051704","citation_count":1,"is_preprint":false},{"pmid":"41715179","id":"PMC_41715179","title":"Glutamine-mediated crosstalk between M2 macrophages and tumor cells via the SLC38A5/FOXM1/CNIH4 axis promotes oral squamous cell carcinoma progression.","date":"2026","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41715179","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8018,"output_tokens":2000,"usd":0.027027,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8963,"output_tokens":2797,"usd":0.05737,"stage2_stop_reason":"end_turn"},"total_usd":0.084397,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2014,\n      \"finding\": \"CNIH4 (human cornichon homologue 4) localizes in the early secretory pathway (ER) and interacts with members of the Class 3 family of GPCRs. Both overexpression and knockdown of CNIH4 cause intracellular retention of GPCRs, demonstrating it is required at an optimal level for GPCR export. Low-level overexpression of CNIH4 rescued cell surface expression of an intracellularly retained mutant β2-adrenergic receptor. Co-immunoprecipitation of CNIH4 with Sec23 and Sec24, components of the COPII coat complex, indicates CNIH4 acts as a cargo-sorting receptor recruiting GPCRs into COPII vesicles for ER export.\",\n      \"method\": \"BRET-based proteomic screen, co-immunoprecipitation, knockdown/overexpression with cell-surface trafficking assays, fluorescence microscopy localization\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP with COPII components, BRET-based interaction screen, gain- and loss-of-function with defined trafficking phenotype, rescue experiment, multiple orthogonal methods in a single focused study\",\n      \"pmids\": [\"24405750\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CNIH4 is a downstream effector in a TMED9-dependent pathway that promotes colon cancer metastasis. TMED9 knockdown compromises TGFα biogenesis and secretion; CNIH4, as a member of the CORNICHON family of TGFα exporters, is part of a positive feedback loop involving TMED9, TGFα, and GLI1 that enhances metastatic behavior. CNIH4 expression is regulated downstream of TMED9/TMED3 antagonism.\",\n      \"method\": \"RNAi knockdown, functional rescue (migration assay), transcriptional profiling, epistasis analysis in colon cancer cell lines\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis via knockdown/rescue, multiple cell types tested, but mechanistic role of CNIH4 itself in TGFα export inferred rather than directly reconstituted\",\n      \"pmids\": [\"31253868\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CNIH4 inhibits ferroptosis in human cervical cancer cells by upregulating SLC7A11, which increases cystine import, elevates intracellular glutathione synthesis, and enhances glutathione peroxidase 4 (GPX4) activity. Silencing SLC7A11 abolished CNIH4-mediated inhibition of ferroptosis, placing SLC7A11 downstream of CNIH4 in this pathway.\",\n      \"method\": \"Lentiviral gain- and loss-of-function, cell viability assays, ferroptosis assays, transcriptome sequencing, SLC7A11 knockdown epistasis\",\n      \"journal\": \"Chemico-biological interactions\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain- and loss-of-function with epistasis (SLC7A11 KD rescue), transcriptomics validation, single lab, no in vitro reconstitution of the CNIH4–SLC7A11 regulatory step\",\n      \"pmids\": [\"37716418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Cnih4 knockout mice (Cnih4tm1a-/-) are fertile, with only slight reductions in sperm count, morphology, and motility compared to wild-type. Testicular histology and ovarian folliculogenesis are normal. Compensatory upregulation of Cnih3 was detected in knockout mice, suggesting functional redundancy within the cornichon family for gametogenesis.\",\n      \"method\": \"Genetic knockout (LacZ reporter insertion), Western blot, immunofluorescence, computer-aided sperm analysis, histology, fertility testing over six months\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic knockout with multiple phenotypic readouts and compensatory mechanism identified; negative finding for essential fertility role is well-supported\",\n      \"pmids\": [\"36657507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CircUCK2(2,3) sponges miR-149-5p to increase CNIH4 protein levels, which in turn amplifies TGFα secretion, leading to activation of EGFR and downstream pAKT and pERK signaling in hepatocellular carcinoma cells. CRISPR-Cas9 disruption and medium transfer assays confirmed the pathway order: circUCK2(2,3) → miR-149-5p suppression → CNIH4 upregulation → TGFα secretion → EGFR activation.\",\n      \"method\": \"RNA immunoprecipitation (RIP), RNA pulldown, CRISPR-Cas9, polysome fractionation, dual luciferase reporter, medium transfer assay, gain- and loss-of-function\",\n      \"journal\": \"Cellular & molecular biology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods establishing pathway order, single lab, CNIH4's direct role in TGFα secretion consistent with prior GPCR trafficking function but not independently reconstituted here\",\n      \"pmids\": [\"39885395\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In oral squamous cell carcinoma, the transcription factor FOXM1 directly binds the CNIH4 enhancer (validated by ChIP-qPCR for H3K27ac and FOXM1 enrichment) to activate CNIH4 transcription. M2 macrophage-derived glutamine, taken up via SLC38A5, enhances FOXM1 recruitment to the CNIH4 enhancer and upregulates CNIH4 expression. CNIH4 overexpression rescued proliferation and invasion impaired by FOXM1 knockdown, placing CNIH4 downstream of FOXM1 in this axis.\",\n      \"method\": \"ChIP-qPCR (H3K27ac and FOXM1), SLC38A5 knockdown, conditioned medium transfer, CCK-8 proliferation assay, Transwell invasion assay, FOXM1 knockdown rescue by CNIH4 overexpression\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct ChIP-qPCR validation of FOXM1 binding to CNIH4 enhancer plus epistasis rescue experiment; single lab, no independent replication\",\n      \"pmids\": [\"41715179\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CNIH4 is an ER-resident transmembrane cargo-sorting receptor that interacts with GPCRs and COPII coat components (Sec23/Sec24) to facilitate ER-to-Golgi export of GPCRs and TGFα-family ligands; in cancer contexts it additionally suppresses ferroptosis by upregulating SLC7A11-mediated cystine import and is transcriptionally activated by FOXM1 in response to metabolic signals, while its expression is post-transcriptionally amplified via a miR-149-5p sponge mechanism that feeds into EGFR/AKT/ERK signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CNIH4 is an ER-resident cargo-sorting receptor that couples transmembrane cargo to the COPII machinery for ER-to-Golgi export [#0]. It localizes to the early secretory pathway, binds Class 3 GPCRs, and co-immunoprecipitates with the COPII coat components Sec23 and Sec24, recruiting GPCRs into COPII vesicles; both overexpression and knockdown cause intracellular receptor retention, and low-level CNIH4 rescues surface expression of a trafficking-defective \\u03b22-adrenergic receptor, indicating that an optimal CNIH4 level is required for export [#0]. As a member of the cornichon family, CNIH4 also functions in the biogenesis and secretion of the EGFR ligand TGF\\u03b1, acting within a TMED9-dependent loop that promotes colon cancer metastasis [#1] and amplifying TGF\\u03b1 secretion to drive EGFR\\u2013AKT\\u2013ERK signaling in hepatocellular carcinoma [#4]. Across cancer contexts CNIH4 is a transcriptional and post-transcriptional node: FOXM1 directly binds the CNIH4 enhancer to activate its transcription in response to macrophage-derived glutamine in oral squamous cell carcinoma [#5], its protein levels are raised by a circUCK2-driven miR-149-5p sponge [#4], and it suppresses ferroptosis in cervical cancer by upregulating SLC7A11 to boost cystine import, glutathione synthesis, and GPX4 activity [#2]. CNIH4 is dispensable for fertility in mice, where loss is buffered by compensatory upregulation of Cnih3 [#3].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2014,\n      \"claim\": \"Established CNIH4's core molecular function: whether the cornichon homologue acts in cargo export was unknown, and this work showed it is an ER cargo-sorting receptor linking GPCRs to the COPII coat.\",\n      \"evidence\": \"BRET interaction screen, reciprocal Co-IP with Sec23/Sec24, knockdown/overexpression trafficking assays and mutant receptor rescue in cultured cells\",\n      \"pmids\": [\"24405750\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of the CNIH4\\u2013cargo or CNIH4\\u2013COPII interface\", \"Cargo selectivity beyond Class 3 GPCRs not defined\", \"Stoichiometry and regulation of the optimal expression level unresolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended CNIH4's cargo repertoire to TGF\\u03b1 and linked it to disease: it was unclear whether CNIH4 contributes to growth-factor secretion, and epistasis placed it in a TMED9/TGF\\u03b1/GLI1 feedback loop driving colon cancer metastasis.\",\n      \"evidence\": \"RNAi knockdown, migration rescue and transcriptional/epistasis analysis in colon cancer cell lines\",\n      \"pmids\": [\"31253868\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"CNIH4's direct role in TGF\\u03b1 export inferred, not biochemically reconstituted\", \"Mechanism of TMED9/TMED3 antagonism on CNIH4 unclear\", \"Relationship between TGF\\u03b1 export and the COPII function from 2014 not directly connected\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined a redox/metabolic role: whether CNIH4 influences cell death was unknown, and this work showed it suppresses ferroptosis through SLC7A11-dependent cystine import.\",\n      \"evidence\": \"Lentiviral gain/loss-of-function, ferroptosis and viability assays, transcriptomics and SLC7A11 knockdown epistasis in cervical cancer cells\",\n      \"pmids\": [\"37716418\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No reconstitution of how CNIH4 regulates SLC7A11\", \"Unclear whether the effect requires CNIH4 trafficking activity\", \"Single lab, single cancer context\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Tested physiological essentiality: it was unknown whether CNIH4 is required in vivo, and a knockout showed it is dispensable for fertility owing to cornichon-family redundancy.\",\n      \"evidence\": \"Cnih4 knockout mice with histology, sperm analysis, fertility testing and detection of compensatory Cnih3 upregulation\",\n      \"pmids\": [\"36657507\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phenotypes outside the reproductive system not examined\", \"Extent of Cnih3 functional substitution not quantified at the molecular level\", \"No tissue-specific or compound knockout\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved post-transcriptional control of CNIH4: it was unclear how CNIH4 levels are elevated in tumors, and a circUCK2/miR-149-5p sponge axis was shown to raise CNIH4 and feed TGF\\u03b1\\u2013EGFR\\u2013AKT/ERK signaling.\",\n      \"evidence\": \"RIP, RNA pulldown, dual luciferase, CRISPR-Cas9, polysome fractionation and medium transfer in hepatocellular carcinoma cells\",\n      \"pmids\": [\"39885395\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"CNIH4's direct TGF\\u03b1-secretion step not reconstituted here\", \"Generality of the circUCK2 axis beyond HCC unknown\", \"Quantitative contribution of CNIH4 versus other miR-149-5p targets unclear\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Resolved transcriptional control of CNIH4: how CNIH4 is induced by the tumor microenvironment was unknown, and FOXM1 was shown to bind the CNIH4 enhancer in response to macrophage-derived glutamine.\",\n      \"evidence\": \"ChIP-qPCR for FOXM1 and H3K27ac, SLC38A5 knockdown, conditioned-medium transfer and FOXM1-knockdown rescue by CNIH4 in oral squamous cell carcinoma\",\n      \"pmids\": [\"41715179\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether glutamine acts solely through FOXM1 is not established\", \"Connection between FOXM1-driven CNIH4 and its trafficking/secretory output not shown\", \"Single lab, no independent replication\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CNIH4's biochemical cargo-export activity mechanistically connects to its downstream effects on TGF\\u03b1/EGFR signaling, ferroptosis suppression via SLC7A11, and metastasis remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No reconstitution linking COPII-dependent cargo sorting to the cancer phenotypes\", \"Whether SLC7A11 is a trafficking cargo of CNIH4 untested\", \"No structural basis for cargo selectivity\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"SEC23\", \"SEC24\", \"TMED9\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}