{"gene":"TMEM98","run_date":"2026-04-28T21:42:59","timeline":{"discoveries":[{"year":2018,"finding":"TMEM98, an ER-associated transmembrane protein, physically binds to the C-terminal fragment of MYRF and inhibits MYRF self-cleavage and N-fragment nuclear translocation, thereby suppressing MYRF-mediated myelin gene transcription. Forced expression of TMEM98 in embryonic chicken spinal cord suppressed OL differentiation and MYRF-induced ectopic myelin gene expression.","method":"Co-immunoprecipitation, forced expression in embryonic chicken spinal cord, Western blot for cleavage products, immunofluorescence for nuclear translocation","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — reciprocal protein interaction plus functional readouts (cleavage inhibition, nuclear translocation, gene expression), replicated independently in a second lab","pmids":["30249802"],"is_preprint":false},{"year":2020,"finding":"TMEM98 inhibits MYRF self-cleavage in the retinal pigment epithelium (RPE); loss of Tmem98 in RPE causes ectopic MYRF activation and abnormal nuclear localization of MYRF, resulting in greatly enlarged, fragile eyes. TMEM98 was identified as a MYRF-interacting protein by proximity labelling (BioID).","method":"Conditional knockout of Tmem98 in RPE, proximity labelling (BioID) to identify MYRF as interactor, immunofluorescence for MYRF nuclear localization, ocular phenotype characterization","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 — proximity labelling plus in vivo conditional KO with clear molecular and anatomical phenotypes; independently corroborates 2018 finding","pmids":["32236127"],"is_preprint":false},{"year":2020,"finding":"TMEM98 interacts with the GSK3-binding protein FRAT2, reduces FRAT2 protein levels, and thereby inhibits FRAT2-mediated induction of β-catenin/TCF signalling. TMEM98 traffics between the plasma membrane and the Golgi apparatus.","method":"Co-immunoprecipitation, β-catenin/TCF reporter assay, subcellular localization by fluorescence imaging (plasma membrane–Golgi recycling)","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2-3 — Co-IP plus functional reporter assay and localization, but single lab with limited mechanistic depth on how TMEM98 reduces FRAT2 levels","pmids":["31961879"],"is_preprint":false},{"year":2020,"finding":"TMEM98 mRNA (not the protein) directly binds to nuclear factor 90 (NF90) protein through an 8-nucleotide motif in the last exon, stabilizes NF90, and promotes gastric cancer cell proliferation and invasion; mutation of this 8-nt motif abolishes TMEM98 mRNA–NF90 binding and the proliferative effect.","method":"RNA-binding protein immunoprecipitation (RIP), RNA pull-down with biotinylated WT and motif-mutated TMEM98 mRNA transcripts, siRNA knockdown, overexpression","journal":"Cell biology international","confidence":"Medium","confidence_rationale":"Tier 2 — RNA pull-down with mutagenesis validation confirms binding site; single lab but two orthogonal RNA-protein interaction methods","pmids":["32379372"],"is_preprint":false},{"year":2017,"finding":"siRNA-mediated knockdown of TMEM98 inhibits IL-8-induced monocyte adhesion to endothelial cells by downregulating ICAM-1, and inhibits vascular smooth muscle cell (VSMC) proliferation and migration by suppressing the AKT/GSK3β/Cyclin D1 signalling pathway; AKT agonist partially restores VSMC proliferation after TMEM98 knockdown.","method":"siRNA knockdown in HUVECs and VSMCs, adhesion assay, proliferation/migration assay, Western blot for ICAM-1, p-AKT, p-GSK3β, Cyclin D1; AKT agonist rescue","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 3 — pathway placement via rescue experiment, but single lab and knockdown-only approach without structural or reconstitution data","pmids":["29152140"],"is_preprint":false},{"year":2020,"finding":"TMEM98 promotes endothelial cell adhesion via induction of ICAM-1 and VCAM-1 expression, and promotes VSMC proliferation and migration via ERK and AKT/GSK3β signalling; TMEM98 and PDGF-BB form a positive feedback loop. TMEM98 protein is secreted.","method":"Gain- and loss-of-function (overexpression and siRNA knockdown), ELISA for PDGF-BB secretion, Western blot for ICAM-1, VCAM-1, ERK, AKT pathway components, adhesion/proliferation/migration assays","journal":"Canadian journal of physiology and pharmacology","confidence":"Medium","confidence_rationale":"Tier 3 — gain- and loss-of-function with pathway readouts; single lab, extends prior finding","pmids":["32893666"],"is_preprint":false},{"year":2015,"finding":"siRNA knockdown of TMEM98 in lung cancer cells (A549, H460) suppresses proliferation, invasion, and migration, with concomitant reduction in MMP-2, MMP-9, RhoC, and MTA1 protein levels, implicating TMEM98 in a pro-invasive signalling context.","method":"siRNA knockdown, CCK8 proliferation assay, invasion/migration assay, Western blot for MMP-2, MMP-9, RhoC, MTA1","journal":"International journal of clinical and experimental pathology","confidence":"Low","confidence_rationale":"Tier 3 — knockdown with phenotypic and protein readouts but no pathway epistasis or mechanistic follow-up; single lab, single method set","pmids":["26884835"],"is_preprint":false},{"year":2021,"finding":"A homology model of TMEM98 predicts a structure comprising antiparallel helix bundles (α4, α5/6, α7, α8) with two transmembrane domains in α1 and α7, confirmed in vitro; all three nanophthalmos-causing proline substitutions (A193P, H196P, R201P) localize to the charge-polarized helix α8 (residues 183–210), suggesting that the structural integrity of the C-terminal helical region is required for normal TMEM98 function.","method":"Protein homology modelling, in vitro confirmation of transmembrane domains, structural mapping of disease mutations","journal":"Experimental eye research","confidence":"Low","confidence_rationale":"Tier 4/1 hybrid — computational model with limited in vitro validation of TM domains; no mutagenesis-based functional rescue","pmids":["33596443"],"is_preprint":false},{"year":2018,"finding":"miR-219-5p directly targets the 3'-UTR of TMEM98 mRNA, downregulating TMEM98 expression; overexpression of TMEM98 reverses hypoxia-induced inhibition of keratinocyte proliferation, migration, and inflammatory cytokine production.","method":"Luciferase 3'-UTR reporter assay (implied by direct binding claim), TMEM98 overexpression in keratinocyte hypoxia model, proliferation/migration assays","journal":"European review for medical and pharmacological sciences","confidence":"Low","confidence_rationale":"Tier 3 — single lab, limited mechanistic detail on binding validation; functional rescue supports regulatory link","pmids":["30338788"],"is_preprint":false},{"year":2020,"finding":"miR-29c-5p directly targets TMEM98 mRNA 3'-UTR (validated by luciferase reporter assay) and its upregulation inhibits HNSCC cell proliferation and migration, placing TMEM98 downstream of miR-29c-5p as a pro-tumorigenic factor.","method":"Luciferase reporter assay with TMEM98 3'-UTR, miR-29c-5p overexpression, in vitro and in vivo proliferation/migration assays","journal":"Aging","confidence":"Low","confidence_rationale":"Tier 3 — luciferase assay validates miRNA–target relationship but mechanistic follow-up of TMEM98 itself is limited; single lab","pmids":["33257597"],"is_preprint":false}],"current_model":"TMEM98 is an ER/plasma membrane-associated transmembrane protein that acts primarily as a negative regulator of the transcription factor MYRF by physically binding its C-terminal fragment and blocking MYRF autoproteolytic self-cleavage and subsequent nuclear translocation, thereby controlling oligodendrocyte myelination and eye size; additionally, TMEM98 suppresses Wnt/β-catenin signalling by interacting with FRAT2, can be secreted to promote vascular cell adhesion and smooth muscle cell proliferation via AKT/GSK3β signalling, and its mRNA (independently of the protein) binds NF90 to promote cancer cell proliferation."},"narrative":{"teleology":[{"year":2015,"claim":"Initial loss-of-function studies established that TMEM98 supports cancer cell proliferation and invasion, but the downstream mechanism was undefined.","evidence":"siRNA knockdown in lung cancer lines with readouts for MMP-2, MMP-9, RhoC, MTA1","pmids":["26884835"],"confidence":"Low","gaps":["Single knockdown approach without epistasis or rescue experiments","No direct molecular target or pathway identified","Not independently replicated"]},{"year":2017,"claim":"Pathway analysis placed TMEM98 upstream of AKT/GSK3β/Cyclin D1 signalling in vascular smooth muscle cells and identified a role in endothelial adhesion via ICAM-1, providing the first signalling pathway context.","evidence":"siRNA knockdown in HUVECs and VSMCs with AKT agonist rescue experiment","pmids":["29152140"],"confidence":"Medium","gaps":["Knockdown-only approach; no structural or reconstitution data","Mechanism by which TMEM98 activates AKT is unknown","No direct binding partner identified in this pathway"]},{"year":2018,"claim":"The central molecular function of TMEM98 was defined: it binds the C-terminal fragment of MYRF at the ER, blocks MYRF autoproteolytic self-cleavage, and prevents the N-fragment from entering the nucleus to activate myelin genes, thus acting as a stoichiometric inhibitor of oligodendrocyte differentiation.","evidence":"Co-immunoprecipitation, forced expression in embryonic chicken spinal cord, Western blot for cleavage products, immunofluorescence for nuclear translocation","pmids":["30249802"],"confidence":"High","gaps":["Binding interface between TMEM98 and MYRF not mapped","Physiological regulation of TMEM98 expression during myelination not established","No in vivo mammalian loss-of-function at this point"]},{"year":2020,"claim":"In vivo conditional knockout of Tmem98 in RPE confirmed the MYRF-inhibitory mechanism in a second tissue and revealed that unrestrained MYRF activation causes pathological eye enlargement, establishing TMEM98 as essential for ocular size control.","evidence":"Conditional KO in mouse RPE, BioID proximity labelling, immunofluorescence for MYRF nuclear localization, ocular phenotyping","pmids":["32236127"],"confidence":"High","gaps":["Whether TMEM98 nanophthalmos mutations (A193P, H196P, R201P) act via the same MYRF derepression mechanism is not functionally demonstrated","Downstream MYRF target genes in RPE not fully catalogued"]},{"year":2020,"claim":"A parallel signalling axis was revealed: TMEM98 binds FRAT2, reduces its protein levels, and thereby suppresses Wnt/β-catenin/TCF signalling, while trafficking between the plasma membrane and Golgi.","evidence":"Co-immunoprecipitation, β-catenin/TCF reporter assay, fluorescence imaging of PM–Golgi cycling","pmids":["31961879"],"confidence":"Medium","gaps":["Mechanism by which TMEM98 reduces FRAT2 levels (degradation vs. sequestration) is unknown","Physiological context for TMEM98-FRAT2 interaction not defined in vivo","Relationship between Wnt pathway inhibition and MYRF regulation is unclear"]},{"year":2020,"claim":"An RNA-level function was uncovered: TMEM98 mRNA, independently of its encoded protein, binds and stabilizes NF90 through a specific 8-nucleotide motif, promoting gastric cancer cell proliferation.","evidence":"RIP, RNA pull-down with WT and motif-mutant TMEM98 transcripts, siRNA knockdown","pmids":["32379372"],"confidence":"Medium","gaps":["Whether the mRNA–NF90 interaction operates in non-cancerous contexts is unknown","Relative contribution of TMEM98 mRNA versus protein functions to cell proliferation not dissected"]},{"year":2020,"claim":"TMEM98 was shown to be secreted and to sustain a positive feedback loop with PDGF-BB, activating ERK and AKT/GSK3β signalling to promote VSMC proliferation and endothelial adhesion molecule expression.","evidence":"Overexpression and siRNA knockdown, ELISA for PDGF-BB, Western blot for adhesion molecules and signalling intermediates","pmids":["32893666"],"confidence":"Medium","gaps":["Secretion mechanism not defined (classical vs. non-classical pathway)","Receptor for secreted TMEM98 unknown","Relationship to the ER-resident MYRF-inhibitory pool not clarified"]},{"year":2021,"claim":"A homology model provided the first structural framework for TMEM98, localizing three nanophthalmos-causing proline substitutions (A193P, H196P, R201P) to a charge-polarized C-terminal helix (α8), suggesting this region is critical for function.","evidence":"Computational homology modelling with in vitro confirmation of transmembrane domains","pmids":["33596443"],"confidence":"Low","gaps":["No experimental structure (X-ray, cryo-EM, or NMR) available","Functional impact of α8 mutations on MYRF binding not tested by mutagenesis","Model awaits independent structural validation"]},{"year":null,"claim":"Key unresolved questions include: the structural basis of TMEM98–MYRF interaction, whether nanophthalmos mutations disrupt MYRF inhibition, how TMEM98's ER-resident and secreted pools are regulated, and whether TMEM98's multiple signalling roles (MYRF, Wnt, AKT) are integrated or context-dependent.","evidence":"","pmids":[],"confidence":"High","gaps":["No experimental structure of TMEM98 or TMEM98–MYRF complex","Functional consequence of disease mutations on MYRF cleavage inhibition not tested","Mechanism of TMEM98 secretion and identity of its extracellular receptor unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,2]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[2]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,4,5]}],"complexes":[],"partners":["MYRF","FRAT2","NF90"],"other_free_text":[]},"mechanistic_narrative":"TMEM98 is a transmembrane protein that functions as a negative regulator of the transcription factor MYRF and modulates Wnt/β-catenin and AKT/GSK3β signalling in multiple tissue contexts. TMEM98 physically binds the C-terminal fragment of MYRF at the endoplasmic reticulum, blocking MYRF autoproteolytic self-cleavage and preventing its N-terminal fragment from translocating to the nucleus to activate myelin gene transcription; conditional loss of Tmem98 in retinal pigment epithelium causes ectopic MYRF activation and nanophthalmos-like eye enlargement [PMID:30249802, PMID:32236127]. TMEM98 also interacts with the GSK3-binding protein FRAT2, reducing FRAT2 levels and thereby inhibiting β-catenin/TCF signalling [PMID:31961879], and promotes endothelial cell adhesion molecule expression and vascular smooth muscle cell proliferation through the AKT/GSK3β/Cyclin D1 axis [PMID:29152140, PMID:32893666]. Independently of its protein product, the TMEM98 mRNA stabilizes NF90 via a specific 8-nucleotide motif, promoting gastric cancer cell proliferation [PMID:32379372]."},"prefetch_data":{"uniprot":{"accession":"Q9Y2Y6","full_name":"Transmembrane protein 98","aliases":["Protein TADA1"],"length_aa":226,"mass_kda":24.6,"function":"Functions as a negative regulator of MYRF in oligodendrocyte differentiation and myelination. Interacts with the C-terminal of MYRF inhibiting MYRF self-cleavage and N-fragment nuclear translocation. The secreted form promotes differentiation of T helper 1 cells (Th1)","subcellular_location":"Cell membrane; Secreted; Secreted, extracellular exosome; Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y2Y6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMEM98","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TMEM98","total_profiled":1310},"omim":[{"mim_id":"615972","title":"NANOPHTHALMOS 4; NNO4","url":"https://www.omim.org/entry/615972"},{"mim_id":"615949","title":"TRANSMEMBRANE PROTEIN 98; TMEM98","url":"https://www.omim.org/entry/615949"},{"mim_id":"608329","title":"MYELIN REGULATORY FACTOR; MYRF","url":"https://www.omim.org/entry/608329"},{"mim_id":"600165","title":"NANOPHTHALMOS 1; NNO1","url":"https://www.omim.org/entry/600165"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"choroid plexus","ntpm":392.6}],"url":"https://www.proteinatlas.org/search/TMEM98"},"hgnc":{"alias_symbol":["DKFZP564K1964"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y2Y6","domains":[{"cath_id":"1.20.1410.10","chopping":"72-206","consensus_level":"high","plddt":81.7085,"start":72,"end":206},{"cath_id":"1.20.5","chopping":"1-36","consensus_level":"medium","plddt":84.8228,"start":1,"end":36}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y2Y6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y2Y6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y2Y6-F1-predicted_aligned_error_v6.png","plddt_mean":72.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMEM98","jax_strain_url":"https://www.jax.org/strain/search?query=TMEM98"},"sequence":{"accession":"Q9Y2Y6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y2Y6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y2Y6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y2Y6"}},"corpus_meta":[{"pmid":"30249802","id":"PMC_30249802","title":"Interactive Repression of MYRF Self-Cleavage and Activity in Oligodendrocyte Differentiation by TMEM98 Protein.","date":"2018","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/30249802","citation_count":56,"is_preprint":false},{"pmid":"24852644","id":"PMC_24852644","title":"Mutation in TMEM98 in a large white kindred with autosomal dominant nanophthalmos linked to 17p12-q12.","date":"2014","source":"JAMA ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/24852644","citation_count":49,"is_preprint":false},{"pmid":"26392740","id":"PMC_26392740","title":"Novel TMEM98 mutations in pedigrees with autosomal dominant nanophthalmos.","date":"2015","source":"Molecular vision","url":"https://pubmed.ncbi.nlm.nih.gov/26392740","citation_count":26,"is_preprint":false},{"pmid":"33203948","id":"PMC_33203948","title":"Novel TMEM98, MFRP, PRSS56 variants in a large United States high hyperopia and nanophthalmos cohort.","date":"2020","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/33203948","citation_count":23,"is_preprint":false},{"pmid":"32236127","id":"PMC_32236127","title":"The nanophthalmos protein TMEM98 inhibits MYRF self-cleavage and is required for eye size specification.","date":"2020","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32236127","citation_count":22,"is_preprint":false},{"pmid":"29152140","id":"PMC_29152140","title":"Inhibition of IL-8-mediated endothelial adhesion, VSMCs proliferation and migration by siRNA-TMEM98 suggests TMEM98's emerging role in atherosclerosis.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/29152140","citation_count":17,"is_preprint":false},{"pmid":"26884835","id":"PMC_26884835","title":"siRNA-TMEM98 inhibits the invasion and migration of lung cancer cells.","date":"2015","source":"International journal of clinical and experimental pathology","url":"https://pubmed.ncbi.nlm.nih.gov/26884835","citation_count":16,"is_preprint":false},{"pmid":"31266059","id":"PMC_31266059","title":"Missense Mutations in the Human Nanophthalmos Gene TMEM98 Cause Retinal Defects in the Mouse.","date":"2019","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/31266059","citation_count":16,"is_preprint":false},{"pmid":"30338788","id":"PMC_30338788","title":"MicroRNA-219-5p inhibits wound healing by targeting TMEM98 in keratinocytes under normoxia and hypoxia condition.","date":"2018","source":"European review for medical and pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/30338788","citation_count":8,"is_preprint":false},{"pmid":"33257597","id":"PMC_33257597","title":"The microRNA miR-29c-5p inhibits cell proliferation and migration by targeting TMEM98 in head and neck carcinoma.","date":"2020","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/33257597","citation_count":6,"is_preprint":false},{"pmid":"32379372","id":"PMC_32379372","title":"TMEM98 mRNA promotes proliferation and invasion of gastric cells by directly interacting with NF90 protein.","date":"2020","source":"Cell biology international","url":"https://pubmed.ncbi.nlm.nih.gov/32379372","citation_count":5,"is_preprint":false},{"pmid":"31961879","id":"PMC_31961879","title":"TMEM98 is a negative regulator of FRAT mediated Wnt/ß-catenin signalling.","date":"2020","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/31961879","citation_count":5,"is_preprint":false},{"pmid":"32893666","id":"PMC_32893666","title":"TMEM98, a novel secretory protein, promotes endothelial cell adhesion as well as vascular smooth muscle cell proliferation and migration.","date":"2020","source":"Canadian journal of physiology and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/32893666","citation_count":5,"is_preprint":false},{"pmid":"33596443","id":"PMC_33596443","title":"A novel proline substitution (Arg201Pro) in alpha helix 8 of TMEM98 causes autosomal dominant nanophthalmos-4, closed angle glaucoma and attenuated visual acuity.","date":"2021","source":"Experimental eye research","url":"https://pubmed.ncbi.nlm.nih.gov/33596443","citation_count":3,"is_preprint":false},{"pmid":"36348534","id":"PMC_36348534","title":"[A family with nanophthalmos caused by a TMEM98 gene variant].","date":"2022","source":"[Zhonghua yan ke za zhi] Chinese journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/36348534","citation_count":1,"is_preprint":false},{"pmid":"41029742","id":"PMC_41029742","title":"Transmembrane protein TMEM98 as a multifunctional regulator in cancer: from signaling pathways to translational implications.","date":"2025","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41029742","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9488,"output_tokens":2632,"usd":0.033972},"stage2":{"model":"claude-opus-4-6","input_tokens":6002,"output_tokens":4796,"usd":0.224865},"total_usd":0.258837,"stage1_batch_id":"msgbatch_01RPbVc9PDH9zQmYK5Hs6srm","stage2_batch_id":"msgbatch_01JVbVLzeKN2yVrsGp3zC8aM","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2018,\n      \"finding\": \"TMEM98, an ER-associated transmembrane protein, physically binds to the C-terminal fragment of MYRF and inhibits MYRF self-cleavage and N-fragment nuclear translocation, thereby suppressing MYRF-mediated myelin gene transcription. Forced expression of TMEM98 in embryonic chicken spinal cord suppressed OL differentiation and MYRF-induced ectopic myelin gene expression.\",\n      \"method\": \"Co-immunoprecipitation, forced expression in embryonic chicken spinal cord, Western blot for cleavage products, immunofluorescence for nuclear translocation\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal protein interaction plus functional readouts (cleavage inhibition, nuclear translocation, gene expression), replicated independently in a second lab\",\n      \"pmids\": [\"30249802\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM98 inhibits MYRF self-cleavage in the retinal pigment epithelium (RPE); loss of Tmem98 in RPE causes ectopic MYRF activation and abnormal nuclear localization of MYRF, resulting in greatly enlarged, fragile eyes. TMEM98 was identified as a MYRF-interacting protein by proximity labelling (BioID).\",\n      \"method\": \"Conditional knockout of Tmem98 in RPE, proximity labelling (BioID) to identify MYRF as interactor, immunofluorescence for MYRF nuclear localization, ocular phenotype characterization\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — proximity labelling plus in vivo conditional KO with clear molecular and anatomical phenotypes; independently corroborates 2018 finding\",\n      \"pmids\": [\"32236127\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM98 interacts with the GSK3-binding protein FRAT2, reduces FRAT2 protein levels, and thereby inhibits FRAT2-mediated induction of β-catenin/TCF signalling. TMEM98 traffics between the plasma membrane and the Golgi apparatus.\",\n      \"method\": \"Co-immunoprecipitation, β-catenin/TCF reporter assay, subcellular localization by fluorescence imaging (plasma membrane–Golgi recycling)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Co-IP plus functional reporter assay and localization, but single lab with limited mechanistic depth on how TMEM98 reduces FRAT2 levels\",\n      \"pmids\": [\"31961879\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM98 mRNA (not the protein) directly binds to nuclear factor 90 (NF90) protein through an 8-nucleotide motif in the last exon, stabilizes NF90, and promotes gastric cancer cell proliferation and invasion; mutation of this 8-nt motif abolishes TMEM98 mRNA–NF90 binding and the proliferative effect.\",\n      \"method\": \"RNA-binding protein immunoprecipitation (RIP), RNA pull-down with biotinylated WT and motif-mutated TMEM98 mRNA transcripts, siRNA knockdown, overexpression\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — RNA pull-down with mutagenesis validation confirms binding site; single lab but two orthogonal RNA-protein interaction methods\",\n      \"pmids\": [\"32379372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"siRNA-mediated knockdown of TMEM98 inhibits IL-8-induced monocyte adhesion to endothelial cells by downregulating ICAM-1, and inhibits vascular smooth muscle cell (VSMC) proliferation and migration by suppressing the AKT/GSK3β/Cyclin D1 signalling pathway; AKT agonist partially restores VSMC proliferation after TMEM98 knockdown.\",\n      \"method\": \"siRNA knockdown in HUVECs and VSMCs, adhesion assay, proliferation/migration assay, Western blot for ICAM-1, p-AKT, p-GSK3β, Cyclin D1; AKT agonist rescue\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — pathway placement via rescue experiment, but single lab and knockdown-only approach without structural or reconstitution data\",\n      \"pmids\": [\"29152140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM98 promotes endothelial cell adhesion via induction of ICAM-1 and VCAM-1 expression, and promotes VSMC proliferation and migration via ERK and AKT/GSK3β signalling; TMEM98 and PDGF-BB form a positive feedback loop. TMEM98 protein is secreted.\",\n      \"method\": \"Gain- and loss-of-function (overexpression and siRNA knockdown), ELISA for PDGF-BB secretion, Western blot for ICAM-1, VCAM-1, ERK, AKT pathway components, adhesion/proliferation/migration assays\",\n      \"journal\": \"Canadian journal of physiology and pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — gain- and loss-of-function with pathway readouts; single lab, extends prior finding\",\n      \"pmids\": [\"32893666\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"siRNA knockdown of TMEM98 in lung cancer cells (A549, H460) suppresses proliferation, invasion, and migration, with concomitant reduction in MMP-2, MMP-9, RhoC, and MTA1 protein levels, implicating TMEM98 in a pro-invasive signalling context.\",\n      \"method\": \"siRNA knockdown, CCK8 proliferation assay, invasion/migration assay, Western blot for MMP-2, MMP-9, RhoC, MTA1\",\n      \"journal\": \"International journal of clinical and experimental pathology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — knockdown with phenotypic and protein readouts but no pathway epistasis or mechanistic follow-up; single lab, single method set\",\n      \"pmids\": [\"26884835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A homology model of TMEM98 predicts a structure comprising antiparallel helix bundles (α4, α5/6, α7, α8) with two transmembrane domains in α1 and α7, confirmed in vitro; all three nanophthalmos-causing proline substitutions (A193P, H196P, R201P) localize to the charge-polarized helix α8 (residues 183–210), suggesting that the structural integrity of the C-terminal helical region is required for normal TMEM98 function.\",\n      \"method\": \"Protein homology modelling, in vitro confirmation of transmembrane domains, structural mapping of disease mutations\",\n      \"journal\": \"Experimental eye research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4/1 hybrid — computational model with limited in vitro validation of TM domains; no mutagenesis-based functional rescue\",\n      \"pmids\": [\"33596443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"miR-219-5p directly targets the 3'-UTR of TMEM98 mRNA, downregulating TMEM98 expression; overexpression of TMEM98 reverses hypoxia-induced inhibition of keratinocyte proliferation, migration, and inflammatory cytokine production.\",\n      \"method\": \"Luciferase 3'-UTR reporter assay (implied by direct binding claim), TMEM98 overexpression in keratinocyte hypoxia model, proliferation/migration assays\",\n      \"journal\": \"European review for medical and pharmacological sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, limited mechanistic detail on binding validation; functional rescue supports regulatory link\",\n      \"pmids\": [\"30338788\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"miR-29c-5p directly targets TMEM98 mRNA 3'-UTR (validated by luciferase reporter assay) and its upregulation inhibits HNSCC cell proliferation and migration, placing TMEM98 downstream of miR-29c-5p as a pro-tumorigenic factor.\",\n      \"method\": \"Luciferase reporter assay with TMEM98 3'-UTR, miR-29c-5p overexpression, in vitro and in vivo proliferation/migration assays\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — luciferase assay validates miRNA–target relationship but mechanistic follow-up of TMEM98 itself is limited; single lab\",\n      \"pmids\": [\"33257597\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TMEM98 is an ER/plasma membrane-associated transmembrane protein that acts primarily as a negative regulator of the transcription factor MYRF by physically binding its C-terminal fragment and blocking MYRF autoproteolytic self-cleavage and subsequent nuclear translocation, thereby controlling oligodendrocyte myelination and eye size; additionally, TMEM98 suppresses Wnt/β-catenin signalling by interacting with FRAT2, can be secreted to promote vascular cell adhesion and smooth muscle cell proliferation via AKT/GSK3β signalling, and its mRNA (independently of the protein) binds NF90 to promote cancer cell proliferation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TMEM98 is a transmembrane protein that functions as a negative regulator of the transcription factor MYRF and modulates Wnt/β-catenin and AKT/GSK3β signalling in multiple tissue contexts. TMEM98 physically binds the C-terminal fragment of MYRF at the endoplasmic reticulum, blocking MYRF autoproteolytic self-cleavage and preventing its N-terminal fragment from translocating to the nucleus to activate myelin gene transcription; conditional loss of Tmem98 in retinal pigment epithelium causes ectopic MYRF activation and nanophthalmos-like eye enlargement [PMID:30249802, PMID:32236127]. TMEM98 also interacts with the GSK3-binding protein FRAT2, reducing FRAT2 levels and thereby inhibiting β-catenin/TCF signalling [PMID:31961879], and promotes endothelial cell adhesion molecule expression and vascular smooth muscle cell proliferation through the AKT/GSK3β/Cyclin D1 axis [PMID:29152140, PMID:32893666]. Independently of its protein product, the TMEM98 mRNA stabilizes NF90 via a specific 8-nucleotide motif, promoting gastric cancer cell proliferation [PMID:32379372].\",\n  \"teleology\": [\n    {\n      \"year\": 2015,\n      \"claim\": \"Initial loss-of-function studies established that TMEM98 supports cancer cell proliferation and invasion, but the downstream mechanism was undefined.\",\n      \"evidence\": \"siRNA knockdown in lung cancer lines with readouts for MMP-2, MMP-9, RhoC, MTA1\",\n      \"pmids\": [\"26884835\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Single knockdown approach without epistasis or rescue experiments\",\n        \"No direct molecular target or pathway identified\",\n        \"Not independently replicated\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Pathway analysis placed TMEM98 upstream of AKT/GSK3β/Cyclin D1 signalling in vascular smooth muscle cells and identified a role in endothelial adhesion via ICAM-1, providing the first signalling pathway context.\",\n      \"evidence\": \"siRNA knockdown in HUVECs and VSMCs with AKT agonist rescue experiment\",\n      \"pmids\": [\"29152140\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Knockdown-only approach; no structural or reconstitution data\",\n        \"Mechanism by which TMEM98 activates AKT is unknown\",\n        \"No direct binding partner identified in this pathway\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"The central molecular function of TMEM98 was defined: it binds the C-terminal fragment of MYRF at the ER, blocks MYRF autoproteolytic self-cleavage, and prevents the N-fragment from entering the nucleus to activate myelin genes, thus acting as a stoichiometric inhibitor of oligodendrocyte differentiation.\",\n      \"evidence\": \"Co-immunoprecipitation, forced expression in embryonic chicken spinal cord, Western blot for cleavage products, immunofluorescence for nuclear translocation\",\n      \"pmids\": [\"30249802\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Binding interface between TMEM98 and MYRF not mapped\",\n        \"Physiological regulation of TMEM98 expression during myelination not established\",\n        \"No in vivo mammalian loss-of-function at this point\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"In vivo conditional knockout of Tmem98 in RPE confirmed the MYRF-inhibitory mechanism in a second tissue and revealed that unrestrained MYRF activation causes pathological eye enlargement, establishing TMEM98 as essential for ocular size control.\",\n      \"evidence\": \"Conditional KO in mouse RPE, BioID proximity labelling, immunofluorescence for MYRF nuclear localization, ocular phenotyping\",\n      \"pmids\": [\"32236127\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TMEM98 nanophthalmos mutations (A193P, H196P, R201P) act via the same MYRF derepression mechanism is not functionally demonstrated\",\n        \"Downstream MYRF target genes in RPE not fully catalogued\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A parallel signalling axis was revealed: TMEM98 binds FRAT2, reduces its protein levels, and thereby suppresses Wnt/β-catenin/TCF signalling, while trafficking between the plasma membrane and Golgi.\",\n      \"evidence\": \"Co-immunoprecipitation, β-catenin/TCF reporter assay, fluorescence imaging of PM–Golgi cycling\",\n      \"pmids\": [\"31961879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which TMEM98 reduces FRAT2 levels (degradation vs. sequestration) is unknown\",\n        \"Physiological context for TMEM98-FRAT2 interaction not defined in vivo\",\n        \"Relationship between Wnt pathway inhibition and MYRF regulation is unclear\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"An RNA-level function was uncovered: TMEM98 mRNA, independently of its encoded protein, binds and stabilizes NF90 through a specific 8-nucleotide motif, promoting gastric cancer cell proliferation.\",\n      \"evidence\": \"RIP, RNA pull-down with WT and motif-mutant TMEM98 transcripts, siRNA knockdown\",\n      \"pmids\": [\"32379372\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether the mRNA–NF90 interaction operates in non-cancerous contexts is unknown\",\n        \"Relative contribution of TMEM98 mRNA versus protein functions to cell proliferation not dissected\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"TMEM98 was shown to be secreted and to sustain a positive feedback loop with PDGF-BB, activating ERK and AKT/GSK3β signalling to promote VSMC proliferation and endothelial adhesion molecule expression.\",\n      \"evidence\": \"Overexpression and siRNA knockdown, ELISA for PDGF-BB, Western blot for adhesion molecules and signalling intermediates\",\n      \"pmids\": [\"32893666\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Secretion mechanism not defined (classical vs. non-classical pathway)\",\n        \"Receptor for secreted TMEM98 unknown\",\n        \"Relationship to the ER-resident MYRF-inhibitory pool not clarified\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"A homology model provided the first structural framework for TMEM98, localizing three nanophthalmos-causing proline substitutions (A193P, H196P, R201P) to a charge-polarized C-terminal helix (α8), suggesting this region is critical for function.\",\n      \"evidence\": \"Computational homology modelling with in vitro confirmation of transmembrane domains\",\n      \"pmids\": [\"33596443\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No experimental structure (X-ray, cryo-EM, or NMR) available\",\n        \"Functional impact of α8 mutations on MYRF binding not tested by mutagenesis\",\n        \"Model awaits independent structural validation\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: the structural basis of TMEM98–MYRF interaction, whether nanophthalmos mutations disrupt MYRF inhibition, how TMEM98's ER-resident and secreted pools are regulated, and whether TMEM98's multiple signalling roles (MYRF, Wnt, AKT) are integrated or context-dependent.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No experimental structure of TMEM98 or TMEM98–MYRF complex\",\n        \"Functional consequence of disease mutations on MYRF cleavage inhibition not tested\",\n        \"Mechanism of TMEM98 secretion and identity of its extracellular receptor unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 4, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"MYRF\",\n      \"FRAT2\",\n      \"NF90\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, I made an error in the pathway section — I included a GO term that's not a valid pathway term. Let me fix that.\n\n```json\n{\n  \"mechanistic_narrative\": \"TMEM98 is a transmembrane protein that functions as a negative regulator of the transcription factor MYRF and modulates Wnt/β-catenin and AKT/GSK3β signalling in multiple tissue contexts. TMEM98 physically binds the C-terminal fragment of MYRF at the endoplasmic reticulum, blocking MYRF autoproteolytic self-cleavage and preventing its N-terminal fragment from translocating to the nucleus to activate myelin gene transcription; conditional loss of Tmem98 in retinal pigment epithelium causes ectopic MYRF activation and pathological eye enlargement [PMID:30249802, PMID:32236127]. TMEM98 also interacts with the GSK3-binding protein FRAT2, reducing FRAT2 levels and thereby inhibiting β-catenin/TCF signalling [PMID:31961879], and promotes endothelial cell adhesion molecule expression and vascular smooth muscle cell proliferation through the AKT/GSK3β/Cyclin D1 axis [PMID:29152140, PMID:32893666]. Independently of its protein product, the TMEM98 mRNA stabilizes NF90 via a specific 8-nucleotide motif, promoting gastric cancer cell proliferation [PMID:32379372].\",\n  \"teleology\": [\n    {\n      \"year\": 2015,\n      \"claim\": \"Initial loss-of-function studies established that TMEM98 supports cancer cell proliferation and invasion, but the downstream mechanism was undefined.\",\n      \"evidence\": \"siRNA knockdown in lung cancer lines with readouts for MMP-2, MMP-9, RhoC, MTA1\",\n      \"pmids\": [\"26884835\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Single knockdown approach without epistasis or rescue experiments\",\n        \"No direct molecular target or pathway identified\",\n        \"Not independently replicated\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Pathway analysis placed TMEM98 upstream of AKT/GSK3β/Cyclin D1 signalling in vascular smooth muscle cells and identified a role in endothelial adhesion via ICAM-1, providing the first signalling pathway context.\",\n      \"evidence\": \"siRNA knockdown in HUVECs and VSMCs with AKT agonist rescue experiment\",\n      \"pmids\": [\"29152140\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Knockdown-only approach; no structural or reconstitution data\",\n        \"Mechanism by which TMEM98 activates AKT is unknown\",\n        \"No direct binding partner identified in this pathway\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"The central molecular function of TMEM98 was defined: it binds the C-terminal fragment of MYRF at the ER, blocks MYRF autoproteolytic self-cleavage, and prevents the N-fragment from entering the nucleus to activate myelin genes, acting as a stoichiometric inhibitor of oligodendrocyte differentiation.\",\n      \"evidence\": \"Co-immunoprecipitation, forced expression in embryonic chicken spinal cord, Western blot for cleavage products, immunofluorescence for nuclear translocation\",\n      \"pmids\": [\"30249802\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Binding interface between TMEM98 and MYRF not mapped\",\n        \"Physiological regulation of TMEM98 expression during myelination not established\",\n        \"No in vivo mammalian loss-of-function at this point\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"In vivo conditional knockout of Tmem98 in RPE confirmed the MYRF-inhibitory mechanism in a second tissue and revealed that unrestrained MYRF activation causes pathological eye enlargement, establishing TMEM98 as essential for ocular size control.\",\n      \"evidence\": \"Conditional KO in mouse RPE, BioID proximity labelling, immunofluorescence for MYRF nuclear localization, ocular phenotyping\",\n      \"pmids\": [\"32236127\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TMEM98 nanophthalmos mutations (A193P, H196P, R201P) act via the same MYRF derepression mechanism is not functionally demonstrated\",\n        \"Downstream MYRF target genes in RPE not fully catalogued\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A parallel signalling axis was revealed: TMEM98 binds FRAT2, reduces its protein levels, and thereby suppresses Wnt/β-catenin/TCF signalling, while trafficking between the plasma membrane and Golgi.\",\n      \"evidence\": \"Co-immunoprecipitation, β-catenin/TCF reporter assay, fluorescence imaging of PM–Golgi cycling\",\n      \"pmids\": [\"31961879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which TMEM98 reduces FRAT2 levels (degradation vs. sequestration) is unknown\",\n        \"Physiological context for TMEM98-FRAT2 interaction not defined in vivo\",\n        \"Relationship between Wnt pathway inhibition and MYRF regulation is unclear\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"An RNA-level function was uncovered: TMEM98 mRNA, independently of its encoded protein, binds and stabilizes NF90 through a specific 8-nucleotide motif, promoting gastric cancer cell proliferation.\",\n      \"evidence\": \"RIP, RNA pull-down with WT and motif-mutant TMEM98 transcripts, siRNA knockdown\",\n      \"pmids\": [\"32379372\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether the mRNA–NF90 interaction operates in non-cancerous contexts is unknown\",\n        \"Relative contribution of TMEM98 mRNA versus protein functions to cell proliferation not dissected\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"TMEM98 was shown to be secreted and to sustain a positive feedback loop with PDGF-BB, activating ERK and AKT/GSK3β signalling to promote VSMC proliferation and endothelial adhesion molecule expression.\",\n      \"evidence\": \"Overexpression and siRNA knockdown, ELISA for PDGF-BB, Western blot for adhesion molecules and signalling intermediates\",\n      \"pmids\": [\"32893666\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Secretion mechanism not defined (classical vs. non-classical pathway)\",\n        \"Receptor for secreted TMEM98 unknown\",\n        \"Relationship to the ER-resident MYRF-inhibitory pool not clarified\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"A homology model provided the first structural framework for TMEM98, localizing three nanophthalmos-causing proline substitutions to a charge-polarized C-terminal helix (α8), suggesting this region is critical for function.\",\n      \"evidence\": \"Computational homology modelling with in vitro confirmation of transmembrane domains\",\n      \"pmids\": [\"33596443\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No experimental structure (X-ray, cryo-EM, or NMR) available\",\n        \"Functional impact of α8 mutations on MYRF binding not tested by mutagenesis\",\n        \"Model awaits independent structural validation\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: the structural basis of TMEM98–MYRF interaction, whether nanophthalmos mutations disrupt MYRF inhibition, how TMEM98's ER-resident and secreted pools are regulated, and whether its multiple signalling roles (MYRF, Wnt, AKT) are integrated or context-dependent.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No experimental structure of TMEM98 or TMEM98–MYRF complex\",\n        \"Functional consequence of disease mutations on MYRF cleavage inhibition not tested\",\n        \"Mechanism of TMEM98 secretion and identity of its extracellular receptor unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 4, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"MYRF\",\n      \"FRAT2\",\n      \"NF90\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}