{"gene":"FOCAD","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2012,"finding":"FOCAD (KIAA1797/focadhesin) co-localizes with vinculin at focal adhesions, and physical interaction between FOCAD and vinculin was demonstrated by co-immunoprecipitation, establishing FOCAD as a focal adhesion complex protein.","method":"Co-immunoprecipitation, immunofluorescence co-localization","journal":"Brain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus immunofluorescence co-localization in a single lab with functional follow-up (colony formation, migration, invasion assays)","pmids":["22427331"],"is_preprint":false},{"year":2012,"finding":"Ectopic re-expression of FOCAD in glioma cells with homozygous FOCAD deletion significantly decreased colony formation, migration, and invasion in vitro, and reduced tumor volume in an orthotopic xenograft mouse model, establishing a tumor suppressor function.","method":"Loss-of-function / gain-of-function in vitro assays (colony formation, migration, invasion), in vivo orthotopic xenograft model","journal":"Brain","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal functional assays in vitro plus in vivo xenograft validation, single lab","pmids":["22427331"],"is_preprint":false},{"year":2019,"finding":"Yeast two-hybrid screening and pull-down assays identified tubulin beta-6 and other tubulin family members as FOCAD-interacting partners; FOCAD co-localized with tubulins at centrosomes/centrioles and reduced microtubule assembly rates.","method":"Yeast two-hybrid screen, pull-down assays, immunofluorescence co-localization","journal":"Acta neuropathologica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus pull-down plus co-localization, single lab","pmids":["31473790"],"is_preprint":false},{"year":2019,"finding":"FOCAD was recruited to microtubules via its interaction partner SLAIN motif family member 2 (SLAIN2), and FOCAD levels peaked in G2/M phase, influencing G2/M progression potentially via polo-like kinase 1 phosphorylation.","method":"Pull-down assays, cell-cycle analysis, co-localization","journal":"Acta neuropathologica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pull-down and cell-cycle analysis in single lab; PLK1 phosphorylation inferred but not directly mutagenized","pmids":["31473790"],"is_preprint":false},{"year":2020,"finding":"NRF2 negatively regulates FOCAD transcription via a NRF2–RPA1–ARE complex. FOCAD in turn promotes FAK activity, which enhances sensitivity to cysteine deprivation-induced ferroptosis by promoting the TCA cycle and mitochondrial ETC Complex I activity.","method":"Transcriptional reporter assays, chromatin immunoprecipitation, FAK activity assays, metabolic assays, in vitro and in vivo combination drug treatment","journal":"Redox biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP confirmed NRF2-RPA1-ARE complex, FAK activity and metabolic assays performed, single lab","pmids":["32898818"],"is_preprint":false},{"year":2022,"finding":"FOCAD deficiency compromises the SKI mRNA surveillance pathway by reducing the levels of RNA helicase SKIC2 and its cofactor SKIC3 (components of the SKI complex), leading to impaired mRNA degradation; this was demonstrated in patient primary cells and CRISPR-Cas9 knockout human hepatic cell lines.","method":"CRISPR-Cas9 knockout, patient primary cell analysis, zebrafish phenocopy model, Western blot/protein quantification","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — CRISPR KO plus patient primary cells plus zebrafish model, multiple orthogonal approaches, published in high-impact journal","pmids":["35864190"],"is_preprint":false},{"year":2022,"finding":"FOCAD knockout hepatocytes exhibited lowered albumin expression, signs of persistent injury, and CCL2 overproduction, indicating FOCAD is required for hepatocyte homeostasis.","method":"CRISPR-Cas9 knockout, gene expression analysis, functional hepatocyte assays","journal":"Nature genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with defined molecular phenotype, single study","pmids":["35864190"],"is_preprint":false},{"year":2022,"finding":"EGR1 binds the FOCAD promoter and negatively regulates FOCAD (and its intronic miR-491-5p) at the transcriptional level, as confirmed by fluorescence reporter gene assay and chromatin immunoprecipitation.","method":"Chromatin immunoprecipitation (ChIP), fluorescence reporter gene assay, bioinformatic analysis","journal":"Progress in biophysics and molecular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP plus reporter assay confirm direct promoter binding, single lab","pmids":["35788362"],"is_preprint":false},{"year":2024,"finding":"FOCAD loss posttranscriptionally destabilizes the SKI complex (reducing SKIC2/SKIC3 levels), creating synthetic lethality with TUT7 and DIS3L2; reintroduction of FOCAD restores the SKI complex and rescues sensitivity to TUT4/7 inhibitors, demonstrating that TUT7 dependency is mechanistically driven by FOCAD loss.","method":"CRISPR knockout, isogenic cell lines, FOCAD re-expression rescue, TUT4/7 inhibitor treatment, in vitro and in vivo proliferation assays","journal":"Molecular cancer therapeutics","confidence":"High","confidence_rationale":"Tier 2 / Strong — CRISPR KO, isogenic rescue, pharmacologic validation in vitro and in vivo, multiple orthogonal methods","pmids":["39235218"],"is_preprint":false},{"year":2025,"finding":"FOCAD loss creates synthetic lethality with HBS1L (a ribosome-rescue GTPase and PELO binding partner); HBS1L loss in FOCAD-deleted cells leads to translational arrest and unfolded protein response activation. FOCAD re-expression rescued HBS1L dependency, and FOCAD knockout rendered FOCAD-intact cells HBS1L-dependent, establishing that FOCAD and the HBS1L/PELO complex together resolve aberrant mRNA-induced ribosomal stalling.","method":"Combinatorial CRISPR screen, genome-wide CRISPR screen in isogenic cells, FOCAD re-expression rescue, in vivo tumor growth assays","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide CRISPR screen, orthogonal genetic validation, isogenic rescue, in vivo validation","pmids":["41101730"],"is_preprint":false},{"year":2026,"finding":"Cryo-EM structures guided development of TNG961, a molecular glue degrader that promotes HBS1L–CRBN–compound complex formation and E3-ligase-dependent HBS1L ubiquitination and degradation, confirming that disruption of the HBS1L/PELO complex in FOCAD-deleted cells induces translational arrest and unfolded protein response activation.","method":"Cryo-EM structural determination, biochemical ubiquitination assays, proteome selectivity profiling, in vitro and in vivo tumor growth assays","journal":"Cancer discovery","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure plus biochemical reconstitution of degradation plus in vivo xenograft, multiple orthogonal methods","pmids":["42001523"],"is_preprint":false},{"year":2021,"finding":"PRICKLE1 and FOCAD proteins co-localize in murine cranial base chondrocytes, and this co-localization is disrupted in Prickle1 hypomorphic mutants, placing FOCAD in a PRICKLE1-dependent pathway governing cranial base morphology.","method":"Immunofluorescence co-localization in mouse tissue, genetic mouse model analysis","journal":"Frontiers in genetics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single co-localization experiment in mouse tissue, no biochemical interaction confirmed","pmids":["34434215"],"is_preprint":false}],"current_model":"FOCAD (focadhesin) is a focal adhesion and centrosome-associated protein that physically interacts with vinculin and, via SLAIN2, with tubulins to reduce microtubule assembly rates and modulate G2/M progression; its transcription is negatively regulated by NRF2 (via a NRF2–RPA1–ARE complex) and by EGR1, while the encoded protein promotes FAK activity to sensitize cells to ferroptosis; at the molecular level, FOCAD is required to maintain stability of the SKI mRNA surveillance complex (SKIC2/SKIC3), and its loss posttranscriptionally destabilizes this complex, impairing aberrant mRNA degradation and ribosome rescue—thereby creating synthetic lethal dependencies on TUT7/DIS3L2 and on the HBS1L/PELO ribosome-rescue complex that are being exploited therapeutically."},"narrative":{"mechanistic_narrative":"FOCAD (focadhesin) is a tumor suppressor and cytoskeleton-associated protein whose principal mechanistic role is to maintain the integrity of the cytoplasmic SKI mRNA surveillance and ribosome-rescue machinery [PMID:22427331, PMID:35864190]. At focal adhesions it co-localizes and physically interacts with vinculin [PMID:22427331], and at centrosomes it binds tubulins and is recruited to microtubules via SLAIN2, reducing microtubule assembly rates and modulating G2/M progression [PMID:31473790]. Its dominant characterized function is post-transcriptional stabilization of the SKI complex: FOCAD is required to sustain levels of the RNA helicase SKIC2 and its cofactor SKIC3, and FOCAD loss destabilizes this complex, impairing degradation of aberrant mRNAs and disrupting hepatocyte homeostasis [PMID:35864190]. Because SKI-dependent surveillance feeds into ribosome rescue, FOCAD-deleted cells become dependent on parallel quality-control routes, generating synthetic lethal vulnerabilities to TUT7/DIS3L2 and to the HBS1L/PELO ribosome-rescue complex, the latter exploited by the molecular-glue HBS1L degrader TNG961 [PMID:39235218, PMID:41101730, PMID:42001523]. FOCAD transcription is negatively controlled by NRF2 through an NRF2–RPA1–ARE complex and by EGR1 binding the FOCAD promoter, and FOCAD promotes FAK activity to sensitize cells to cysteine-deprivation ferroptosis [PMID:32898818, PMID:35788362].","teleology":[{"year":2012,"claim":"Established FOCAD's first molecular context by showing it is a focal adhesion protein and acts as a tumor suppressor, framing why its loss matters in cancer.","evidence":"Reciprocal co-IP and immunofluorescence with vinculin plus colony/migration/invasion assays and orthotopic glioma xenografts","pmids":["22427331"],"confidence":"High","gaps":["Mechanism linking focal adhesion localization to tumor suppression not defined","No structural basis for vinculin interaction"]},{"year":2019,"claim":"Extended FOCAD's cytoskeletal role to the microtubule system, addressing how it might influence cell division.","evidence":"Yeast two-hybrid, pull-down, and co-localization identifying tubulins and SLAIN2; cell-cycle analysis showing G2/M-peaked levels","pmids":["31473790"],"confidence":"Medium","gaps":["PLK1 phosphorylation inferred, not directly mutagenized","Functional consequence of reduced microtubule assembly for tumor suppression unresolved"]},{"year":2020,"claim":"Identified upstream transcriptional repression by NRF2 and a downstream FAK-driven metabolic role linking FOCAD to ferroptosis sensitivity.","evidence":"Reporter assays, ChIP of NRF2–RPA1–ARE complex, FAK activity and metabolic assays, in vivo combination treatment","pmids":["32898818"],"confidence":"Medium","gaps":["Single lab; how FOCAD promotes FAK activity mechanistically not defined","Connection between FAK axis and other FOCAD functions unclear"]},{"year":2022,"claim":"Defined FOCAD's core molecular function as post-transcriptional stabilization of the SKI mRNA surveillance complex, explaining a tissue homeostasis phenotype.","evidence":"CRISPR-Cas9 KO, patient primary cells, zebrafish phenocopy, protein quantification of SKIC2/SKIC3; hepatocyte functional assays","pmids":["35864190"],"confidence":"High","gaps":["Direct binding interface between FOCAD and SKI components not structurally resolved","How FOCAD prevents SKI complex turnover mechanistically unknown"]},{"year":2022,"claim":"Identified EGR1 as a second transcriptional repressor of FOCAD and its intronic miR-491-5p.","evidence":"ChIP and fluorescence reporter assay confirming direct promoter binding","pmids":["35788362"],"confidence":"Medium","gaps":["Physiological context of EGR1 regulation not established","Interplay between EGR1 and NRF2 repression unresolved"]},{"year":2024,"claim":"Showed FOCAD loss creates a druggable synthetic lethality with TUT7/DIS3L2, converting the SKI-stabilization function into a therapeutic strategy.","evidence":"Isogenic CRISPR KO, FOCAD re-expression rescue, TUT4/7 inhibitor treatment in vitro and in vivo","pmids":["39235218"],"confidence":"High","gaps":["Full set of mRNA substrates rerouted to TUT7/DIS3L2 not catalogued"]},{"year":2025,"claim":"Demonstrated a second synthetic lethality with the HBS1L/PELO ribosome-rescue complex, linking FOCAD's SKI defect to ribosomal stalling resolution.","evidence":"Combinatorial and genome-wide CRISPR screens in isogenic cells, FOCAD re-expression rescue, in vivo tumor assays","pmids":["41101730"],"confidence":"High","gaps":["Precise stalled-mRNA species accumulating in FOCAD-deleted cells not defined"]},{"year":2026,"claim":"Provided structural and pharmacologic proof-of-concept by developing a molecular-glue degrader that exploits the FOCAD-loss HBS1L dependency.","evidence":"Cryo-EM of HBS1L–CRBN–compound complex, biochemical ubiquitination, selectivity profiling, in vivo tumor growth","pmids":["42001523"],"confidence":"High","gaps":["Clinical translation not addressed","Selectivity in FOCAD-intact tissues over chronic dosing unknown"]},{"year":null,"claim":"How FOCAD physically stabilizes the SKI complex and whether its focal adhesion/microtubule roles are mechanistically linked to its mRNA surveillance function remain unresolved.","evidence":"No structural or biochemical study in the corpus connects FOCAD's cytoskeletal localization to SKI complex stabilization","pmids":[],"confidence":"Low","gaps":["No atomic structure of FOCAD bound to SKI components","Unclear whether vinculin/tubulin binding and SKI stabilization are independent activities"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,2]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[4,7]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[2,3]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[5,8,9]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[1,8,9]}],"complexes":["SKI complex (SKIC2/SKIC3)","focal adhesion"],"partners":["VCL","SLAIN2","TUBB6","SKIC2","SKIC3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q5VW36","full_name":"Focadhesin","aliases":[],"length_aa":1801,"mass_kda":200.1,"function":"Required for the maintenance of SKIC2 and SKIC3 proteostatic levels in the liver. May be involved in the regulation of RNA degradation by the exosome complex (PubMed:35864190). Potential tumor suppressor in gliomas","subcellular_location":"Cell junction, focal adhesion; Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q5VW36/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FOCAD","classification":"Not Classified","n_dependent_lines":13,"n_total_lines":1208,"dependency_fraction":0.01076158940397351},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CTTN","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"RACK1","stoichiometry":0.2},{"gene":"RPS16","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/FOCAD","total_profiled":1310},"omim":[{"mim_id":"619991","title":"LIVER DISEASE, SEVERE CONGENITAL; SCOLIV","url":"https://www.omim.org/entry/619991"},{"mim_id":"614606","title":"FOCADHESIN; FOCAD","url":"https://www.omim.org/entry/614606"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"choroid plexus","ntpm":34.9}],"url":"https://www.proteinatlas.org/search/FOCAD"},"hgnc":{"alias_symbol":["FLJ20375"],"prev_symbol":["KIAA1797"]},"alphafold":{"accession":"Q5VW36","domains":[{"cath_id":"1.20.1440","chopping":"233-362","consensus_level":"medium","plddt":86.9002,"start":233,"end":362},{"cath_id":"1.25.40","chopping":"1452-1574","consensus_level":"medium","plddt":83.2775,"start":1452,"end":1574}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5VW36","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q5VW36-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q5VW36-F1-predicted_aligned_error_v6.png","plddt_mean":82.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FOCAD","jax_strain_url":"https://www.jax.org/strain/search?query=FOCAD"},"sequence":{"accession":"Q5VW36","fasta_url":"https://rest.uniprot.org/uniprotkb/Q5VW36.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q5VW36/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5VW36"}},"corpus_meta":[{"pmid":"32898818","id":"PMC_32898818","title":"NRF2 regulates the sensitivity of human NSCLC cells to cystine deprivation-induced ferroptosis via FOCAD-FAK signaling pathway.","date":"2020","source":"Redox biology","url":"https://pubmed.ncbi.nlm.nih.gov/32898818","citation_count":115,"is_preprint":false},{"pmid":"22427331","id":"PMC_22427331","title":"KIAA1797/FOCAD encodes a novel focal adhesion protein with tumour suppressor function in gliomas.","date":"2012","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/22427331","citation_count":49,"is_preprint":false},{"pmid":"25712196","id":"PMC_25712196","title":"Germline deletions in the tumour suppressor gene FOCAD are associated with polyposis and colorectal cancer development.","date":"2015","source":"The Journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/25712196","citation_count":28,"is_preprint":false},{"pmid":"35864190","id":"PMC_35864190","title":"Loss of FOCAD, operating via the SKI messenger RNA surveillance pathway, causes a pediatric syndrome with liver cirrhosis.","date":"2022","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35864190","citation_count":23,"is_preprint":false},{"pmid":"31473790","id":"PMC_31473790","title":"FOCAD loss impacts microtubule assembly, G2/M progression and patient survival in astrocytic gliomas.","date":"2019","source":"Acta neuropathologica","url":"https://pubmed.ncbi.nlm.nih.gov/31473790","citation_count":19,"is_preprint":false},{"pmid":"20601674","id":"PMC_20601674","title":"Bivariate genetic association of KIAA1797 with heart rate in American Indians: the Strong Heart Family Study.","date":"2010","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20601674","citation_count":18,"is_preprint":false},{"pmid":"34685504","id":"PMC_34685504","title":"Identification of the Novel Tumor Suppressor Role of FOCAD/miR-491-5p to Inhibit Cancer Stemness, Drug Resistance and Metastasis via Regulating RABIF/MMP Signaling in Triple Negative Breast Cancer.","date":"2021","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/34685504","citation_count":13,"is_preprint":false},{"pmid":"34434215","id":"PMC_34434215","title":"PRICKLE1 × FOCAD Interaction Revealed by Genome-Wide vQTL Analysis of Human Facial Traits.","date":"2021","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34434215","citation_count":8,"is_preprint":false},{"pmid":"39235218","id":"PMC_39235218","title":"Targeting the Synthetic Lethal Relationship between FOCAD and TUT7 Represents a Potential Therapeutic Opportunity for TUT4/7 Small-Molecule Inhibitors in Cancer.","date":"2024","source":"Molecular cancer therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/39235218","citation_count":5,"is_preprint":false},{"pmid":"35788362","id":"PMC_35788362","title":"FOCAD/miR-491-5p, downregulated by EGR1, function as tumor suppressor by inhibiting the proliferation and migration of gastric cancer cells.","date":"2022","source":"Progress in biophysics and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/35788362","citation_count":3,"is_preprint":false},{"pmid":"35622075","id":"PMC_35622075","title":"FOCAD Indel in a Family With Juvenile Polyposis Syndrome.","date":"2022","source":"Journal of pediatric gastroenterology and nutrition","url":"https://pubmed.ncbi.nlm.nih.gov/35622075","citation_count":1,"is_preprint":false},{"pmid":"41101730","id":"PMC_41101730","title":"Tumor suppressor collateral damage screens reveal mRNA homeostasis protein HBS1L as a novel vulnerability in ch9p21 driven FOCAD deleted cancer.","date":"2025","source":"Biochimica et biophysica acta. Molecular cell research","url":"https://pubmed.ncbi.nlm.nih.gov/41101730","citation_count":1,"is_preprint":false},{"pmid":"41189834","id":"PMC_41189834","title":"FOCAD Gene Defect Resulting in Rapidly Progressing Neonatal Liver Cirrhosis Requiring Transplant.","date":"2025","source":"Cureus","url":"https://pubmed.ncbi.nlm.nih.gov/41189834","citation_count":1,"is_preprint":false},{"pmid":"41608453","id":"PMC_41608453","title":"A novel homozygous splice-site variant in the FOCAD gene causing infantile liver cirrhosis and neutropenia: expanding disease phenotype and successful surgical treatment.","date":"2026","source":"Frontiers in medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41608453","citation_count":0,"is_preprint":false},{"pmid":"42001523","id":"PMC_42001523","title":"TNG961 is a selective oral HBS1L molecular glue degrader for the treatment of FOCAD-deleted cancers.","date":"2026","source":"Cancer discovery","url":"https://pubmed.ncbi.nlm.nih.gov/42001523","citation_count":0,"is_preprint":false},{"pmid":"40662096","id":"PMC_40662096","title":"A Rare Case of Neonatal Cholestasis Linked to FOCAD Gene Variants: Exploring the Variable Phenotypic Presentation and Its Implications.","date":"2025","source":"Case reports in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40662096","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9947,"output_tokens":2761,"usd":0.035628,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10171,"output_tokens":2885,"usd":0.06149,"stage2_stop_reason":"end_turn"},"total_usd":0.097118,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2012,\n      \"finding\": \"FOCAD (KIAA1797/focadhesin) co-localizes with vinculin at focal adhesions, and physical interaction between FOCAD and vinculin was demonstrated by co-immunoprecipitation, establishing FOCAD as a focal adhesion complex protein.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence co-localization\",\n      \"journal\": \"Brain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus immunofluorescence co-localization in a single lab with functional follow-up (colony formation, migration, invasion assays)\",\n      \"pmids\": [\"22427331\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Ectopic re-expression of FOCAD in glioma cells with homozygous FOCAD deletion significantly decreased colony formation, migration, and invasion in vitro, and reduced tumor volume in an orthotopic xenograft mouse model, establishing a tumor suppressor function.\",\n      \"method\": \"Loss-of-function / gain-of-function in vitro assays (colony formation, migration, invasion), in vivo orthotopic xenograft model\",\n      \"journal\": \"Brain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal functional assays in vitro plus in vivo xenograft validation, single lab\",\n      \"pmids\": [\"22427331\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Yeast two-hybrid screening and pull-down assays identified tubulin beta-6 and other tubulin family members as FOCAD-interacting partners; FOCAD co-localized with tubulins at centrosomes/centrioles and reduced microtubule assembly rates.\",\n      \"method\": \"Yeast two-hybrid screen, pull-down assays, immunofluorescence co-localization\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus pull-down plus co-localization, single lab\",\n      \"pmids\": [\"31473790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"FOCAD was recruited to microtubules via its interaction partner SLAIN motif family member 2 (SLAIN2), and FOCAD levels peaked in G2/M phase, influencing G2/M progression potentially via polo-like kinase 1 phosphorylation.\",\n      \"method\": \"Pull-down assays, cell-cycle analysis, co-localization\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pull-down and cell-cycle analysis in single lab; PLK1 phosphorylation inferred but not directly mutagenized\",\n      \"pmids\": [\"31473790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"NRF2 negatively regulates FOCAD transcription via a NRF2–RPA1–ARE complex. FOCAD in turn promotes FAK activity, which enhances sensitivity to cysteine deprivation-induced ferroptosis by promoting the TCA cycle and mitochondrial ETC Complex I activity.\",\n      \"method\": \"Transcriptional reporter assays, chromatin immunoprecipitation, FAK activity assays, metabolic assays, in vitro and in vivo combination drug treatment\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP confirmed NRF2-RPA1-ARE complex, FAK activity and metabolic assays performed, single lab\",\n      \"pmids\": [\"32898818\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FOCAD deficiency compromises the SKI mRNA surveillance pathway by reducing the levels of RNA helicase SKIC2 and its cofactor SKIC3 (components of the SKI complex), leading to impaired mRNA degradation; this was demonstrated in patient primary cells and CRISPR-Cas9 knockout human hepatic cell lines.\",\n      \"method\": \"CRISPR-Cas9 knockout, patient primary cell analysis, zebrafish phenocopy model, Western blot/protein quantification\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — CRISPR KO plus patient primary cells plus zebrafish model, multiple orthogonal approaches, published in high-impact journal\",\n      \"pmids\": [\"35864190\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FOCAD knockout hepatocytes exhibited lowered albumin expression, signs of persistent injury, and CCL2 overproduction, indicating FOCAD is required for hepatocyte homeostasis.\",\n      \"method\": \"CRISPR-Cas9 knockout, gene expression analysis, functional hepatocyte assays\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with defined molecular phenotype, single study\",\n      \"pmids\": [\"35864190\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"EGR1 binds the FOCAD promoter and negatively regulates FOCAD (and its intronic miR-491-5p) at the transcriptional level, as confirmed by fluorescence reporter gene assay and chromatin immunoprecipitation.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP), fluorescence reporter gene assay, bioinformatic analysis\",\n      \"journal\": \"Progress in biophysics and molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP plus reporter assay confirm direct promoter binding, single lab\",\n      \"pmids\": [\"35788362\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"FOCAD loss posttranscriptionally destabilizes the SKI complex (reducing SKIC2/SKIC3 levels), creating synthetic lethality with TUT7 and DIS3L2; reintroduction of FOCAD restores the SKI complex and rescues sensitivity to TUT4/7 inhibitors, demonstrating that TUT7 dependency is mechanistically driven by FOCAD loss.\",\n      \"method\": \"CRISPR knockout, isogenic cell lines, FOCAD re-expression rescue, TUT4/7 inhibitor treatment, in vitro and in vivo proliferation assays\",\n      \"journal\": \"Molecular cancer therapeutics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — CRISPR KO, isogenic rescue, pharmacologic validation in vitro and in vivo, multiple orthogonal methods\",\n      \"pmids\": [\"39235218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"FOCAD loss creates synthetic lethality with HBS1L (a ribosome-rescue GTPase and PELO binding partner); HBS1L loss in FOCAD-deleted cells leads to translational arrest and unfolded protein response activation. FOCAD re-expression rescued HBS1L dependency, and FOCAD knockout rendered FOCAD-intact cells HBS1L-dependent, establishing that FOCAD and the HBS1L/PELO complex together resolve aberrant mRNA-induced ribosomal stalling.\",\n      \"method\": \"Combinatorial CRISPR screen, genome-wide CRISPR screen in isogenic cells, FOCAD re-expression rescue, in vivo tumor growth assays\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide CRISPR screen, orthogonal genetic validation, isogenic rescue, in vivo validation\",\n      \"pmids\": [\"41101730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Cryo-EM structures guided development of TNG961, a molecular glue degrader that promotes HBS1L–CRBN–compound complex formation and E3-ligase-dependent HBS1L ubiquitination and degradation, confirming that disruption of the HBS1L/PELO complex in FOCAD-deleted cells induces translational arrest and unfolded protein response activation.\",\n      \"method\": \"Cryo-EM structural determination, biochemical ubiquitination assays, proteome selectivity profiling, in vitro and in vivo tumor growth assays\",\n      \"journal\": \"Cancer discovery\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure plus biochemical reconstitution of degradation plus in vivo xenograft, multiple orthogonal methods\",\n      \"pmids\": [\"42001523\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PRICKLE1 and FOCAD proteins co-localize in murine cranial base chondrocytes, and this co-localization is disrupted in Prickle1 hypomorphic mutants, placing FOCAD in a PRICKLE1-dependent pathway governing cranial base morphology.\",\n      \"method\": \"Immunofluorescence co-localization in mouse tissue, genetic mouse model analysis\",\n      \"journal\": \"Frontiers in genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single co-localization experiment in mouse tissue, no biochemical interaction confirmed\",\n      \"pmids\": [\"34434215\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FOCAD (focadhesin) is a focal adhesion and centrosome-associated protein that physically interacts with vinculin and, via SLAIN2, with tubulins to reduce microtubule assembly rates and modulate G2/M progression; its transcription is negatively regulated by NRF2 (via a NRF2–RPA1–ARE complex) and by EGR1, while the encoded protein promotes FAK activity to sensitize cells to ferroptosis; at the molecular level, FOCAD is required to maintain stability of the SKI mRNA surveillance complex (SKIC2/SKIC3), and its loss posttranscriptionally destabilizes this complex, impairing aberrant mRNA degradation and ribosome rescue—thereby creating synthetic lethal dependencies on TUT7/DIS3L2 and on the HBS1L/PELO ribosome-rescue complex that are being exploited therapeutically.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FOCAD (focadhesin) is a tumor suppressor and cytoskeleton-associated protein whose principal mechanistic role is to maintain the integrity of the cytoplasmic SKI mRNA surveillance and ribosome-rescue machinery [#1, #5]. At focal adhesions it co-localizes and physically interacts with vinculin [#0], and at centrosomes it binds tubulins and is recruited to microtubules via SLAIN2, reducing microtubule assembly rates and modulating G2/M progression [#2, #3]. Its dominant characterized function is post-transcriptional stabilization of the SKI complex: FOCAD is required to sustain levels of the RNA helicase SKIC2 and its cofactor SKIC3, and FOCAD loss destabilizes this complex, impairing degradation of aberrant mRNAs and disrupting hepatocyte homeostasis [#5, #6]. Because SKI-dependent surveillance feeds into ribosome rescue, FOCAD-deleted cells become dependent on parallel quality-control routes, generating synthetic lethal vulnerabilities to TUT7/DIS3L2 and to the HBS1L/PELO ribosome-rescue complex, the latter exploited by the molecular-glue HBS1L degrader TNG961 [#8, #9, #10]. FOCAD transcription is negatively controlled by NRF2 through an NRF2–RPA1–ARE complex and by EGR1 binding the FOCAD promoter, and FOCAD promotes FAK activity to sensitize cells to cysteine-deprivation ferroptosis [#4, #7].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2012,\n      \"claim\": \"Established FOCAD's first molecular context by showing it is a focal adhesion protein and acts as a tumor suppressor, framing why its loss matters in cancer.\",\n      \"evidence\": \"Reciprocal co-IP and immunofluorescence with vinculin plus colony/migration/invasion assays and orthotopic glioma xenografts\",\n      \"pmids\": [\"22427331\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking focal adhesion localization to tumor suppression not defined\", \"No structural basis for vinculin interaction\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended FOCAD's cytoskeletal role to the microtubule system, addressing how it might influence cell division.\",\n      \"evidence\": \"Yeast two-hybrid, pull-down, and co-localization identifying tubulins and SLAIN2; cell-cycle analysis showing G2/M-peaked levels\",\n      \"pmids\": [\"31473790\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"PLK1 phosphorylation inferred, not directly mutagenized\", \"Functional consequence of reduced microtubule assembly for tumor suppression unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified upstream transcriptional repression by NRF2 and a downstream FAK-driven metabolic role linking FOCAD to ferroptosis sensitivity.\",\n      \"evidence\": \"Reporter assays, ChIP of NRF2–RPA1–ARE complex, FAK activity and metabolic assays, in vivo combination treatment\",\n      \"pmids\": [\"32898818\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab; how FOCAD promotes FAK activity mechanistically not defined\", \"Connection between FAK axis and other FOCAD functions unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined FOCAD's core molecular function as post-transcriptional stabilization of the SKI mRNA surveillance complex, explaining a tissue homeostasis phenotype.\",\n      \"evidence\": \"CRISPR-Cas9 KO, patient primary cells, zebrafish phenocopy, protein quantification of SKIC2/SKIC3; hepatocyte functional assays\",\n      \"pmids\": [\"35864190\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct binding interface between FOCAD and SKI components not structurally resolved\", \"How FOCAD prevents SKI complex turnover mechanistically unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified EGR1 as a second transcriptional repressor of FOCAD and its intronic miR-491-5p.\",\n      \"evidence\": \"ChIP and fluorescence reporter assay confirming direct promoter binding\",\n      \"pmids\": [\"35788362\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological context of EGR1 regulation not established\", \"Interplay between EGR1 and NRF2 repression unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed FOCAD loss creates a druggable synthetic lethality with TUT7/DIS3L2, converting the SKI-stabilization function into a therapeutic strategy.\",\n      \"evidence\": \"Isogenic CRISPR KO, FOCAD re-expression rescue, TUT4/7 inhibitor treatment in vitro and in vivo\",\n      \"pmids\": [\"39235218\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full set of mRNA substrates rerouted to TUT7/DIS3L2 not catalogued\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated a second synthetic lethality with the HBS1L/PELO ribosome-rescue complex, linking FOCAD's SKI defect to ribosomal stalling resolution.\",\n      \"evidence\": \"Combinatorial and genome-wide CRISPR screens in isogenic cells, FOCAD re-expression rescue, in vivo tumor assays\",\n      \"pmids\": [\"41101730\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise stalled-mRNA species accumulating in FOCAD-deleted cells not defined\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Provided structural and pharmacologic proof-of-concept by developing a molecular-glue degrader that exploits the FOCAD-loss HBS1L dependency.\",\n      \"evidence\": \"Cryo-EM of HBS1L–CRBN–compound complex, biochemical ubiquitination, selectivity profiling, in vivo tumor growth\",\n      \"pmids\": [\"42001523\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Clinical translation not addressed\", \"Selectivity in FOCAD-intact tissues over chronic dosing unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How FOCAD physically stabilizes the SKI complex and whether its focal adhesion/microtubule roles are mechanistically linked to its mRNA surveillance function remain unresolved.\",\n      \"evidence\": \"No structural or biochemical study in the corpus connects FOCAD's cytoskeletal localization to SKI complex stabilization\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No atomic structure of FOCAD bound to SKI components\", \"Unclear whether vinculin/tubulin binding and SKI stabilization are independent activities\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [4, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [5, 8, 9]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [1, 8, 9]}\n    ],\n    \"complexes\": [\"SKI complex (SKIC2/SKIC3)\", \"focal adhesion\"],\n    \"partners\": [\"VCL\", \"SLAIN2\", \"TUBB6\", \"SKIC2\", \"SKIC3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}