{"gene":"GIGYF1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":2017,"finding":"Crystal structures of the 4EHP-binding regions of GIGYF1 and GIGYF2 in complex with 4EHP reveal that GIGYF1/2 use auxiliary sequences to selectively bind 4EHP but not eIF4E, providing the molecular basis for selectivity. Structure-based complementation assays in GIGYF1/2-null cells demonstrate that 4EHP requires interactions with GIGYF1/2 to down-regulate target mRNA expression, showing GIGYF1/2 are required for repressive activity rather than merely facilitating 4EHP recruitment.","method":"X-ray crystallography; structure-based mutagenesis; complementation assays in GIGYF1/2-null cell lines","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures resolved with functional validation by mutagenesis and complementation assays in null cells, multiple orthogonal methods in one rigorous study","pmids":["28698298"],"is_preprint":false},{"year":2020,"finding":"4EHP-GIGYF1/2 complexes trigger co-translational mRNA decay. Human cells lacking these proteins accumulate mRNAs with prominent ribosome pausing (including transcripts encoding secretory/membrane-bound proteins and tubulin subunits). Co-translational mRNA decay by 4EHP-GIGYF1/2 requires ribosome stalling, cap-structure interaction, and interaction with DDX6 and ZNF598. GIGYF1/2 co-translationally bind to mRNAs to mark transcripts with perturbed elongation for decay.","method":"Genetic knockout of 4EHP/GIGYF1/2 in human cells; ribosome profiling; mRNA stability assays; disruption of specific protein-protein interactions","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular phenotype, multiple orthogonal methods (ribosome profiling, mRNA decay assays, interaction disruption), mechanistic pathway placement","pmids":["33053355"],"is_preprint":false},{"year":2019,"finding":"ZNF598 binds the GYF domain of GIGYF1 through three proline-rich motifs in a TTP-like manner, contributing to the same 4EHP-GIGYF1/2 regulatory module. ZNF598 is required for the regulation of known TTP targets including IL-8 and CSF2 mRNA, and ZNF598 binds IL-8 mRNA but not TNF mRNA.","method":"Co-immunoprecipitation; RNA sequencing; RNA binding assays; identification of proline-rich motif interactions with GYF domain","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal interaction mapping and RNA-seq in single lab, two orthogonal methods","pmids":["30917308"],"is_preprint":false},{"year":2021,"finding":"C. elegans GYF-1 (ortholog of GIGYF1) directly interacts with IFE-4 (ortholog of 4EHP). Recruitment of GYF-1 to mRNA reporters leads to potent translation repression without affecting poly(A) tail or mRNA stability. Loss of gyf-1 is synthetic lethal with hypomorphic alleles of miR-35-42 and let-7 miRNAs, and engineered mutations in gyf-1 abolishing interaction with IFE-4 phenocopy this lethality, placing GYF-1/4EHP function in specific miRNA cascades.","method":"Proteomic surveys (co-immunoprecipitation); in vitro and in vivo mRNA reporter assays; genetic epistasis (synthetic lethality with miRNA hypomorphs); structure-based mutagenesis of GYF-1","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro reconstitution of translational repression, genetic epistasis, and mutagenesis all in one study demonstrating mechanism","pmids":["33758928"],"is_preprint":false},{"year":2022,"finding":"GIGYF1 and GIGYF2 regulate the function of the VCP/p97 (Cdc48 homolog) in human cells in response to transcription stress, similarly to yeast Smy2. The apoptosis-inducing effect of VCP inhibitors NMS-873 and CB-5083 is GIGYF1/2-dependent.","method":"Genetic and biochemical epistasis in yeast and human cells; multicopy suppressor assays; VCP inhibitor sensitivity assays with GIGYF1/2 manipulation","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis and biochemical evidence in both yeast and human cells, single lab with two orthogonal approaches","pmids":["36288698"],"is_preprint":false},{"year":2022,"finding":"GIGYF1 regulates the recycling of IGF-1R to the cell surface. Knockout of GIGYF1 leads to decreased levels of IGF-1R on the cell surface, disrupting the IGF-1R/ERK signaling pathway. In a conditional KO mouse model, GIGYF1 haploinsufficiency in the developing brain reduced upper-layer cortical neuron numbers, decreased proliferation and increased differentiation of neural progenitor cells.","method":"Conditional knockout mouse model; cell surface IGF-1R quantification; ERK signaling pathway analysis; cortical neuron counting; neural progenitor cell proliferation/differentiation assays","journal":"The Journal of clinical investigation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular and molecular phenotypes, single lab, multiple readouts","pmids":["35917186"],"is_preprint":false},{"year":2024,"finding":"GIGYF1 represses cellular mRNA translation through a 4EHP-independent mechanism. Upon recruitment to a target mRNA, GIGYF1 binds to subunits of eIF3 at the eIF3-eIF4G1 interaction interface, disrupting eIF3 binding to eIF4G1, resulting in transcript-specific translational repression. Depletion of GIGYF1 induces a robust immune response by derepressing IFN-β production.","method":"Biochemical interaction assays (Co-IP/pulldown of eIF3 and eIF4G1); loss-of-function (GIGYF1 depletion); IFN-β reporter assays; tethered mRNA reporter assays","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct biochemical interaction mapping and KD with defined mechanistic phenotype, single lab, multiple orthogonal assays","pmids":["39018414"],"is_preprint":false},{"year":2018,"finding":"GIGYF1 knockdown in SHSY-5Y neuroblastoma cells under high-glucose conditions reversed the decline in phosphorylated IGF1R, p-AKT, and p-ERK, and promoted proliferation and migration while inhibiting apoptosis, indicating that GIGYF1 negatively regulates IGF1R signaling in this context.","method":"siRNA knockdown; Western blotting for p-IGF1R, p-AKT, p-ERK; cell proliferation/migration/apoptosis assays","journal":"DNA and cell biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single knockdown approach with signaling readouts, no direct binding or mechanistic dissection","pmids":["30376373"],"is_preprint":false},{"year":2022,"finding":"miR-145-5p directly targets GIGYF1 (confirmed by dual-luciferase reporter assay). Overexpression of miR-145-5p downregulates GIGYF1 expression, promoting cardiomyocyte proliferation and inhibiting apoptosis; simultaneous upregulation of both miR-145-5p and GIGYF1 reversed these effects.","method":"Dual-luciferase reporter assay; siRNA/miRNA overexpression; Western blotting; flow cytometry","journal":"Cellular and molecular biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, luciferase validation of miRNA targeting but no mechanistic dissection of GIGYF1 protein function itself","pmids":["35809317"],"is_preprint":false}],"current_model":"GIGYF1 is a translational repressor that operates through at least two distinct mechanisms: (1) it selectively binds 4EHP (not eIF4E) via auxiliary sequences and is required—not merely accessory—for 4EHP-mediated co-translational mRNA decay targeting transcripts with ribosome stalling; and (2) independently of 4EHP, GIGYF1 binds eIF3 at the eIF3-eIF4G1 interface to disrupt translation initiation of specific mRNAs including those encoding antiviral cytokines. GIGYF1 also interacts with GRB10 and regulates IGF-1R surface recycling and downstream ERK/AKT signaling, and functions as a regulator of VCP/p97 activity during transcription stress."},"narrative":{"mechanistic_narrative":"GIGYF1 is a transcript-selective translational repressor that operates through two distinct mechanisms and additionally tunes growth-factor signaling [PMID:28698298, PMID:33053355, PMID:39018414]. In its cap-dependent mode, GIGYF1 uses auxiliary sequences to selectively bind the eIF4E homolog 4EHP (but not eIF4E), and structure-based complementation in null cells establishes that GIGYF1 is required for—not merely facilitative of—4EHP-mediated repression [PMID:28698298]. The 4EHP-GIGYF1 module marks transcripts undergoing ribosome stalling for co-translational mRNA decay, a process requiring cap interaction, ribosome stalling, and binding to DDX6 and the ribosome-collision sensor ZNF598, which docks onto the GIGYF1 GYF domain through proline-rich motifs [PMID:33053355, PMID:30917308]. The repressive activity is conserved: the C. elegans ortholog GYF-1 directly binds the 4EHP ortholog IFE-4 to silence reporter mRNAs without affecting poly(A) length or stability, and this interaction is genetically required within specific miRNA cascades [PMID:33758928]. In a 4EHP-independent mode, GIGYF1 binds eIF3 subunits at the eIF3-eIF4G1 interface to block initiation of specific mRNAs, including those encoding antiviral cytokines, such that GIGYF1 loss derepresses IFN-β production [PMID:39018414]. Beyond translational control, GIGYF1 promotes recycling of IGF-1R to the cell surface and thereby supports IGF-1R/ERK signaling and cortical neurogenesis [PMID:35917186], and it regulates VCP/p97 activity during transcription stress, with VCP-inhibitor-induced apoptosis being GIGYF1/2-dependent [PMID:36288698].","teleology":[{"year":2017,"claim":"Established the structural basis for how GIGYF1 selects 4EHP over eIF4E and showed that GIGYF1 is essential for the complex's repressive output, reframing it as a required functional component rather than a passive scaffold.","evidence":"X-ray crystallography of GIGYF1/2-4EHP complexes with structure-based mutagenesis and complementation in GIGYF1/2-null cells","pmids":["28698298"],"confidence":"High","gaps":["Does not identify the endogenous target mRNAs repressed by the complex","Does not resolve how the complex is recruited to specific transcripts"]},{"year":2019,"claim":"Identified ZNF598 as a GYF-domain ligand connecting ribosome-quality-control machinery to the GIGYF1/4EHP module and to regulation of TTP-class inflammatory transcripts.","evidence":"Co-immunoprecipitation, proline-rich motif mapping, RNA-seq and RNA-binding assays in human cells","pmids":["30917308"],"confidence":"Medium","gaps":["Single-lab interaction mapping","Does not establish how ZNF598 binding triggers downstream decay versus repression"]},{"year":2020,"claim":"Defined the functional output of the 4EHP-GIGYF1/2 complex as co-translational mRNA decay of transcripts with ribosome pausing, linking elongation defects to transcript turnover.","evidence":"Genetic knockout of 4EHP/GIGYF1/2 plus ribosome profiling, mRNA stability assays and targeted interaction disruption in human cells","pmids":["33053355"],"confidence":"High","gaps":["Does not separate GIGYF1 from GIGYF2 contributions","Mechanism coupling stalled ribosome detection to decay enzymes not fully reconstituted"]},{"year":2021,"claim":"Demonstrated evolutionary conservation of the GIGYF/4EHP repressive mechanism and placed it genetically within defined miRNA pathways in an intact organism.","evidence":"Co-IP, in vitro and in vivo mRNA reporter assays, and genetic epistasis/synthetic lethality with miRNA hypomorphs in C. elegans","pmids":["33758928"],"confidence":"High","gaps":["Does not address whether human GIGYF1 acts in analogous miRNA cascades","Endogenous target spectrum in worm not defined"]},{"year":2022,"claim":"Extended GIGYF1 function beyond translation by showing it regulates IGF-1R surface recycling and downstream ERK signaling, with developmental consequences for cortical neurogenesis.","evidence":"Conditional knockout mouse, cell-surface IGF-1R quantification, ERK pathway analysis, and neural progenitor proliferation/differentiation assays","pmids":["35917186"],"confidence":"Medium","gaps":["Molecular link between GIGYF1 and the IGF-1R recycling machinery not defined","Relationship to the 4EHP translational role unclear"]},{"year":2022,"claim":"Implicated GIGYF1/2 in VCP/p97 regulation during transcription stress, connecting it to a proteostasis/stress axis and to VCP-inhibitor sensitivity.","evidence":"Genetic and biochemical epistasis in yeast and human cells, multicopy suppressor and VCP-inhibitor sensitivity assays","pmids":["36288698"],"confidence":"Medium","gaps":["Direct biochemical interaction with VCP not established","Mechanism by which GIGYF1/2 modulates VCP activity unknown"]},{"year":2024,"claim":"Uncovered a second, 4EHP-independent repressive mechanism in which GIGYF1 disrupts eIF3-eIF4G1 contacts to block initiation, explaining its control of antiviral cytokine production.","evidence":"Co-IP/pulldown of eIF3 and eIF4G1, GIGYF1 depletion, tethered mRNA reporter and IFN-β reporter assays","pmids":["39018414"],"confidence":"Medium","gaps":["Structural basis of eIF3 interface engagement not resolved","How target selection differs between the 4EHP-dependent and -independent modes unknown"]},{"year":null,"claim":"How GIGYF1 chooses between co-translational decay, initiation blockade, IGF-1R recycling, and VCP regulation on a given transcript or in a given cellular context remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model integrating the translational and signaling roles","Determinants of GIGYF1 recruitment to specific mRNAs unknown","GIGYF1-specific versus GIGYF2-shared functions not systematically separated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0045182","term_label":"translation regulator activity","supporting_discovery_ids":[0,1,3,6]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[1]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,6]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,6]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[1]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5]}],"complexes":["4EHP-GIGYF1 translational repression complex"],"partners":["EIF4E2","ZNF598","DDX6","EIF3","EIF4G1","GRB10","IGF1R","VCP"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O75420","full_name":"GRB10-interacting GYF protein 1","aliases":["PERQ amino acid-rich with GYF domain-containing protein 1"],"length_aa":1035,"mass_kda":114.6,"function":"May act cooperatively with GRB10 to regulate tyrosine kinase receptor signaling. May increase IGF1 receptor phosphorylation under IGF1 stimulation as well as phosphorylation of IRS1 and SHC1 (By similarity)","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/O75420/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GIGYF1","classification":"Not Classified","n_dependent_lines":43,"n_total_lines":1208,"dependency_fraction":0.03559602649006623},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GIGYF1","total_profiled":1310},"omim":[{"mim_id":"612064","title":"GRB10-INTERACTING GYF PROTEIN 1; GIGYF1","url":"https://www.omim.org/entry/612064"},{"mim_id":"612003","title":"GRB10-INTERACTING GYF PROTEIN 2; GIGYF2","url":"https://www.omim.org/entry/612003"},{"mim_id":"605895","title":"EUKARYOTIC TRANSLATION INITIATION FACTOR 4E FAMILY, MEMBER 2; EIF4E2","url":"https://www.omim.org/entry/605895"},{"mim_id":"601523","title":"GROWTH FACTOR RECEPTOR-BOUND PROTEIN 10; GRB10","url":"https://www.omim.org/entry/601523"},{"mim_id":"147370","title":"INSULIN-LIKE GROWTH FACTOR I RECEPTOR; IGF1R","url":"https://www.omim.org/entry/147370"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Microtubules","reliability":"Additional"},{"location":"Mitotic spindle","reliability":"Additional"},{"location":"Primary cilium","reliability":"Additional"},{"location":"Basal body","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/GIGYF1"},"hgnc":{"alias_symbol":["GYF1"],"prev_symbol":["PERQ1"]},"alphafold":{"accession":"O75420","domains":[{"cath_id":"3.30.1490.40","chopping":"478-544","consensus_level":"high","plddt":85.5675,"start":478,"end":544},{"cath_id":"1.20.5","chopping":"546-580","consensus_level":"medium","plddt":73.13,"start":546,"end":580}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O75420","model_url":"https://alphafold.ebi.ac.uk/files/AF-O75420-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O75420-F1-predicted_aligned_error_v6.png","plddt_mean":55.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GIGYF1","jax_strain_url":"https://www.jax.org/strain/search?query=GIGYF1"},"sequence":{"accession":"O75420","fasta_url":"https://rest.uniprot.org/uniprotkb/O75420.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O75420/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O75420"}},"corpus_meta":[{"pmid":"28698298","id":"PMC_28698298","title":"GIGYF1/2 proteins use auxiliary sequences to selectively bind to 4EHP and repress target mRNA expression.","date":"2017","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/28698298","citation_count":64,"is_preprint":false},{"pmid":"33053355","id":"PMC_33053355","title":"4EHP and GIGYF1/2 Mediate Translation-Coupled Messenger RNA Decay.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/33053355","citation_count":51,"is_preprint":false},{"pmid":"30917308","id":"PMC_30917308","title":"GIGYF1/2-Driven Cooperation between ZNF598 and TTP in Posttranscriptional Regulation of Inflammatory Signaling.","date":"2019","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/30917308","citation_count":48,"is_preprint":false},{"pmid":"34234147","id":"PMC_34234147","title":"GIGYF1 loss of function is associated with clonal mosaicism and adverse metabolic health.","date":"2021","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/34234147","citation_count":35,"is_preprint":false},{"pmid":"34732801","id":"PMC_34732801","title":"Gene-level analysis of rare variants in 379,066 whole exome sequences identifies an association of GIGYF1 loss of function with type 2 diabetes.","date":"2021","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/34732801","citation_count":28,"is_preprint":false},{"pmid":"33758928","id":"PMC_33758928","title":"microRNA-mediated translation repression through GYF-1 and IFE-4 in C. elegans development.","date":"2021","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/33758928","citation_count":26,"is_preprint":false},{"pmid":"35917186","id":"PMC_35917186","title":"GIGYF1 disruption associates with autism and impaired IGF-1R signaling.","date":"2022","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/35917186","citation_count":21,"is_preprint":false},{"pmid":"36288698","id":"PMC_36288698","title":"Yeast Smy2 and its human homologs GIGYF1 and -2 regulate Cdc48/VCP function during transcription stress.","date":"2022","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/36288698","citation_count":9,"is_preprint":false},{"pmid":"37484805","id":"PMC_37484805","title":"Low Expression of GIGYF1 Inhibits Metastasis, Proliferation, and Promotes Apoptosis and Autophagy of Gastric Cancer Cells.","date":"2023","source":"International journal of medical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37484805","citation_count":9,"is_preprint":false},{"pmid":"35809317","id":"PMC_35809317","title":"Effects of miR-145-5p on cardiomyocyte proliferation and apoptosis, GIGYF1 expression and oxidative stress response in rats with myocardial ischemia-reperfusion.","date":"2022","source":"Cellular and molecular biology (Noisy-le-Grand, France)","url":"https://pubmed.ncbi.nlm.nih.gov/35809317","citation_count":9,"is_preprint":false},{"pmid":"39018414","id":"PMC_39018414","title":"Repression of mRNA translation initiation by GIGYF1 via disrupting the eIF3-eIF4G1 interaction.","date":"2024","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/39018414","citation_count":7,"is_preprint":false},{"pmid":"30376373","id":"PMC_30376373","title":"Modulation of IGF1R Signaling Pathway by GIGYF1 in High Glucose-Induced SHSY-5Y Cells.","date":"2018","source":"DNA and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/30376373","citation_count":6,"is_preprint":false},{"pmid":"36924980","id":"PMC_36924980","title":"Genetic Ablation of GIGYF1, Associated With Autism, Causes Behavioral and Neurodevelopmental Defects in Zebrafish and Mice.","date":"2023","source":"Biological psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/36924980","citation_count":4,"is_preprint":false},{"pmid":"36189799","id":"PMC_36189799","title":"GIGYF1-disturbed IGF-1R recycling: a potential contributor to autism spectrum disorder pathogenesis?","date":"2022","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/36189799","citation_count":4,"is_preprint":false},{"pmid":"38733530","id":"PMC_38733530","title":"circPDK1 competitively binds miR-4731-5p to mediate GIGYF1 expression and increase paclitaxel sensitivity in non-small cell lung cancer.","date":"2024","source":"Discover oncology","url":"https://pubmed.ncbi.nlm.nih.gov/38733530","citation_count":3,"is_preprint":false},{"pmid":"37936059","id":"PMC_37936059","title":"Isolation of a novel multiple-heavy metal resistant Lampropedia aestuarii GYF-1 and investigation of its bioremediation potential.","date":"2023","source":"BMC microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/37936059","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.13.24315422","title":"Discovery of novel obesity genes through cross-ancestry analysis","date":"2024-10-16","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.13.24315422","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10469,"output_tokens":2591,"usd":0.035136,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9792,"output_tokens":2950,"usd":0.061355,"stage2_stop_reason":"end_turn"},"total_usd":0.096491,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"Crystal structures of the 4EHP-binding regions of GIGYF1 and GIGYF2 in complex with 4EHP reveal that GIGYF1/2 use auxiliary sequences to selectively bind 4EHP but not eIF4E, providing the molecular basis for selectivity. Structure-based complementation assays in GIGYF1/2-null cells demonstrate that 4EHP requires interactions with GIGYF1/2 to down-regulate target mRNA expression, showing GIGYF1/2 are required for repressive activity rather than merely facilitating 4EHP recruitment.\",\n      \"method\": \"X-ray crystallography; structure-based mutagenesis; complementation assays in GIGYF1/2-null cell lines\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures resolved with functional validation by mutagenesis and complementation assays in null cells, multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"28698298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"4EHP-GIGYF1/2 complexes trigger co-translational mRNA decay. Human cells lacking these proteins accumulate mRNAs with prominent ribosome pausing (including transcripts encoding secretory/membrane-bound proteins and tubulin subunits). Co-translational mRNA decay by 4EHP-GIGYF1/2 requires ribosome stalling, cap-structure interaction, and interaction with DDX6 and ZNF598. GIGYF1/2 co-translationally bind to mRNAs to mark transcripts with perturbed elongation for decay.\",\n      \"method\": \"Genetic knockout of 4EHP/GIGYF1/2 in human cells; ribosome profiling; mRNA stability assays; disruption of specific protein-protein interactions\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular phenotype, multiple orthogonal methods (ribosome profiling, mRNA decay assays, interaction disruption), mechanistic pathway placement\",\n      \"pmids\": [\"33053355\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ZNF598 binds the GYF domain of GIGYF1 through three proline-rich motifs in a TTP-like manner, contributing to the same 4EHP-GIGYF1/2 regulatory module. ZNF598 is required for the regulation of known TTP targets including IL-8 and CSF2 mRNA, and ZNF598 binds IL-8 mRNA but not TNF mRNA.\",\n      \"method\": \"Co-immunoprecipitation; RNA sequencing; RNA binding assays; identification of proline-rich motif interactions with GYF domain\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interaction mapping and RNA-seq in single lab, two orthogonal methods\",\n      \"pmids\": [\"30917308\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"C. elegans GYF-1 (ortholog of GIGYF1) directly interacts with IFE-4 (ortholog of 4EHP). Recruitment of GYF-1 to mRNA reporters leads to potent translation repression without affecting poly(A) tail or mRNA stability. Loss of gyf-1 is synthetic lethal with hypomorphic alleles of miR-35-42 and let-7 miRNAs, and engineered mutations in gyf-1 abolishing interaction with IFE-4 phenocopy this lethality, placing GYF-1/4EHP function in specific miRNA cascades.\",\n      \"method\": \"Proteomic surveys (co-immunoprecipitation); in vitro and in vivo mRNA reporter assays; genetic epistasis (synthetic lethality with miRNA hypomorphs); structure-based mutagenesis of GYF-1\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro reconstitution of translational repression, genetic epistasis, and mutagenesis all in one study demonstrating mechanism\",\n      \"pmids\": [\"33758928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GIGYF1 and GIGYF2 regulate the function of the VCP/p97 (Cdc48 homolog) in human cells in response to transcription stress, similarly to yeast Smy2. The apoptosis-inducing effect of VCP inhibitors NMS-873 and CB-5083 is GIGYF1/2-dependent.\",\n      \"method\": \"Genetic and biochemical epistasis in yeast and human cells; multicopy suppressor assays; VCP inhibitor sensitivity assays with GIGYF1/2 manipulation\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis and biochemical evidence in both yeast and human cells, single lab with two orthogonal approaches\",\n      \"pmids\": [\"36288698\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GIGYF1 regulates the recycling of IGF-1R to the cell surface. Knockout of GIGYF1 leads to decreased levels of IGF-1R on the cell surface, disrupting the IGF-1R/ERK signaling pathway. In a conditional KO mouse model, GIGYF1 haploinsufficiency in the developing brain reduced upper-layer cortical neuron numbers, decreased proliferation and increased differentiation of neural progenitor cells.\",\n      \"method\": \"Conditional knockout mouse model; cell surface IGF-1R quantification; ERK signaling pathway analysis; cortical neuron counting; neural progenitor cell proliferation/differentiation assays\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular and molecular phenotypes, single lab, multiple readouts\",\n      \"pmids\": [\"35917186\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GIGYF1 represses cellular mRNA translation through a 4EHP-independent mechanism. Upon recruitment to a target mRNA, GIGYF1 binds to subunits of eIF3 at the eIF3-eIF4G1 interaction interface, disrupting eIF3 binding to eIF4G1, resulting in transcript-specific translational repression. Depletion of GIGYF1 induces a robust immune response by derepressing IFN-β production.\",\n      \"method\": \"Biochemical interaction assays (Co-IP/pulldown of eIF3 and eIF4G1); loss-of-function (GIGYF1 depletion); IFN-β reporter assays; tethered mRNA reporter assays\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct biochemical interaction mapping and KD with defined mechanistic phenotype, single lab, multiple orthogonal assays\",\n      \"pmids\": [\"39018414\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GIGYF1 knockdown in SHSY-5Y neuroblastoma cells under high-glucose conditions reversed the decline in phosphorylated IGF1R, p-AKT, and p-ERK, and promoted proliferation and migration while inhibiting apoptosis, indicating that GIGYF1 negatively regulates IGF1R signaling in this context.\",\n      \"method\": \"siRNA knockdown; Western blotting for p-IGF1R, p-AKT, p-ERK; cell proliferation/migration/apoptosis assays\",\n      \"journal\": \"DNA and cell biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single knockdown approach with signaling readouts, no direct binding or mechanistic dissection\",\n      \"pmids\": [\"30376373\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"miR-145-5p directly targets GIGYF1 (confirmed by dual-luciferase reporter assay). Overexpression of miR-145-5p downregulates GIGYF1 expression, promoting cardiomyocyte proliferation and inhibiting apoptosis; simultaneous upregulation of both miR-145-5p and GIGYF1 reversed these effects.\",\n      \"method\": \"Dual-luciferase reporter assay; siRNA/miRNA overexpression; Western blotting; flow cytometry\",\n      \"journal\": \"Cellular and molecular biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, luciferase validation of miRNA targeting but no mechanistic dissection of GIGYF1 protein function itself\",\n      \"pmids\": [\"35809317\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GIGYF1 is a translational repressor that operates through at least two distinct mechanisms: (1) it selectively binds 4EHP (not eIF4E) via auxiliary sequences and is required—not merely accessory—for 4EHP-mediated co-translational mRNA decay targeting transcripts with ribosome stalling; and (2) independently of 4EHP, GIGYF1 binds eIF3 at the eIF3-eIF4G1 interface to disrupt translation initiation of specific mRNAs including those encoding antiviral cytokines. GIGYF1 also interacts with GRB10 and regulates IGF-1R surface recycling and downstream ERK/AKT signaling, and functions as a regulator of VCP/p97 activity during transcription stress.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GIGYF1 is a transcript-selective translational repressor that operates through two distinct mechanisms and additionally tunes growth-factor signaling [#0, #1, #6]. In its cap-dependent mode, GIGYF1 uses auxiliary sequences to selectively bind the eIF4E homolog 4EHP (but not eIF4E), and structure-based complementation in null cells establishes that GIGYF1 is required for—not merely facilitative of—4EHP-mediated repression [#0]. The 4EHP-GIGYF1 module marks transcripts undergoing ribosome stalling for co-translational mRNA decay, a process requiring cap interaction, ribosome stalling, and binding to DDX6 and the ribosome-collision sensor ZNF598, which docks onto the GIGYF1 GYF domain through proline-rich motifs [#1, #2]. The repressive activity is conserved: the C. elegans ortholog GYF-1 directly binds the 4EHP ortholog IFE-4 to silence reporter mRNAs without affecting poly(A) length or stability, and this interaction is genetically required within specific miRNA cascades [#3]. In a 4EHP-independent mode, GIGYF1 binds eIF3 subunits at the eIF3-eIF4G1 interface to block initiation of specific mRNAs, including those encoding antiviral cytokines, such that GIGYF1 loss derepresses IFN-\\u03b2 production [#6]. Beyond translational control, GIGYF1 promotes recycling of IGF-1R to the cell surface and thereby supports IGF-1R/ERK signaling and cortical neurogenesis [#5], and it regulates VCP/p97 activity during transcription stress, with VCP-inhibitor-induced apoptosis being GIGYF1/2-dependent [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established the structural basis for how GIGYF1 selects 4EHP over eIF4E and showed that GIGYF1 is essential for the complex's repressive output, reframing it as a required functional component rather than a passive scaffold.\",\n      \"evidence\": \"X-ray crystallography of GIGYF1/2-4EHP complexes with structure-based mutagenesis and complementation in GIGYF1/2-null cells\",\n      \"pmids\": [\"28698298\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not identify the endogenous target mRNAs repressed by the complex\", \"Does not resolve how the complex is recruited to specific transcripts\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identified ZNF598 as a GYF-domain ligand connecting ribosome-quality-control machinery to the GIGYF1/4EHP module and to regulation of TTP-class inflammatory transcripts.\",\n      \"evidence\": \"Co-immunoprecipitation, proline-rich motif mapping, RNA-seq and RNA-binding assays in human cells\",\n      \"pmids\": [\"30917308\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab interaction mapping\", \"Does not establish how ZNF598 binding triggers downstream decay versus repression\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined the functional output of the 4EHP-GIGYF1/2 complex as co-translational mRNA decay of transcripts with ribosome pausing, linking elongation defects to transcript turnover.\",\n      \"evidence\": \"Genetic knockout of 4EHP/GIGYF1/2 plus ribosome profiling, mRNA stability assays and targeted interaction disruption in human cells\",\n      \"pmids\": [\"33053355\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not separate GIGYF1 from GIGYF2 contributions\", \"Mechanism coupling stalled ribosome detection to decay enzymes not fully reconstituted\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrated evolutionary conservation of the GIGYF/4EHP repressive mechanism and placed it genetically within defined miRNA pathways in an intact organism.\",\n      \"evidence\": \"Co-IP, in vitro and in vivo mRNA reporter assays, and genetic epistasis/synthetic lethality with miRNA hypomorphs in C. elegans\",\n      \"pmids\": [\"33758928\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address whether human GIGYF1 acts in analogous miRNA cascades\", \"Endogenous target spectrum in worm not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Extended GIGYF1 function beyond translation by showing it regulates IGF-1R surface recycling and downstream ERK signaling, with developmental consequences for cortical neurogenesis.\",\n      \"evidence\": \"Conditional knockout mouse, cell-surface IGF-1R quantification, ERK pathway analysis, and neural progenitor proliferation/differentiation assays\",\n      \"pmids\": [\"35917186\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular link between GIGYF1 and the IGF-1R recycling machinery not defined\", \"Relationship to the 4EHP translational role unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Implicated GIGYF1/2 in VCP/p97 regulation during transcription stress, connecting it to a proteostasis/stress axis and to VCP-inhibitor sensitivity.\",\n      \"evidence\": \"Genetic and biochemical epistasis in yeast and human cells, multicopy suppressor and VCP-inhibitor sensitivity assays\",\n      \"pmids\": [\"36288698\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical interaction with VCP not established\", \"Mechanism by which GIGYF1/2 modulates VCP activity unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Uncovered a second, 4EHP-independent repressive mechanism in which GIGYF1 disrupts eIF3-eIF4G1 contacts to block initiation, explaining its control of antiviral cytokine production.\",\n      \"evidence\": \"Co-IP/pulldown of eIF3 and eIF4G1, GIGYF1 depletion, tethered mRNA reporter and IFN-\\u03b2 reporter assays\",\n      \"pmids\": [\"39018414\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of eIF3 interface engagement not resolved\", \"How target selection differs between the 4EHP-dependent and -independent modes unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How GIGYF1 chooses between co-translational decay, initiation blockade, IGF-1R recycling, and VCP regulation on a given transcript or in a given cellular context remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model integrating the translational and signaling roles\", \"Determinants of GIGYF1 recruitment to specific mRNAs unknown\", \"GIGYF1-specific versus GIGYF2-shared functions not systematically separated\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0045182\", \"supporting_discovery_ids\": [0, 1, 3, 6]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-72766\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [\n      \"4EHP-GIGYF1 translational repression complex\"\n    ],\n    \"partners\": [\n      \"EIF4E2\",\n      \"ZNF598\",\n      \"DDX6\",\n      \"EIF3\",\n      \"EIF4G1\",\n      \"GRB10\",\n      \"IGF1R\",\n      \"VCP\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}