{"gene":"TERB2","run_date":"2026-04-28T21:42:58","timeline":{"discoveries":[{"year":2018,"finding":"MAJIN-TERB2 forms a 2:2 hetero-tetramer that binds strongly to DNA and is tethered through long flexible linkers to the inner nuclear membrane and two TRF1-binding 1:1 TERB2-TERB1 complexes; MAJIN-TERB2-TERB1 recruits telomere-bound TRF1, which is then displaced during pachytene, allowing MAJIN-TERB2-TERB1 to bind telomeric DNA and form a mature attachment plate.","method":"Crystal structure of MAJIN-TERB2, X-ray and light scattering of wider complexes, structured illumination microscopy, biochemical DNA-binding assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 — crystal structure combined with biochemical and imaging validation in a single rigorous study","pmids":["30559341"],"is_preprint":false},{"year":2019,"finding":"Crystal structures of human TERB1-TERB2 and TERB2-MAJIN subcomplexes were resolved; specific disruption of either the TERB1-TERB2 or TERB2-MAJIN interaction in mouse Terb2 abolishes telomere attachment to the nuclear envelope and causes aberrant homologous pairing and disordered synapsis, establishing TERB2 as a central scaffold linking telomeres to the NE via a TERB1-TERB2-MAJIN interaction network.","method":"Crystal structure determination, mouse Terb2 knock-in mutations disrupting specific protein-protein interfaces, cytological analysis of meiotic phenotypes","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 — crystal structures combined with in vivo mutagenesis and functional rescue experiments","pmids":["30718482"],"is_preprint":false},{"year":2017,"finding":"TRF1 directs the assembly of the TERB1-TERB2-MAJIN complex; a TERB2-binding (T2B) domain in TERB1 is dispensable for TRF1-TERB1 interaction but essential for TERB1-TERB2 interaction and telomere attachment to the NE; TERB2-MAJIN is required for telomere attachment to the NE downstream of TRF1.","method":"Germ-cell-specific Trf1 knockout mouse, domain-specific knockout/mutation analysis, Co-immunoprecipitation, cytological analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with specific domain dissection in mouse models, replicated by subsequent structural studies","pmids":["29141207"],"is_preprint":false},{"year":2022,"finding":"The TERB1 MYB domain is dispensable for telomere localization of TERB1 and the downstream TERB2-MAJIN complex and for homologous pairing, but instead regulates cohesin enrichment and axial element remodeling at the early-to-late pachytene transition, thereby suppressing telomere erosion.","method":"Terb1 point mutant mice lacking the MYB domain, immunofluorescence, cytological analysis of cohesin and axial element dynamics, telomere length analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 — clean mouse genetic model with multiple orthogonal readouts establishing TERB2-MAJIN localization downstream of TERB1 MYB","pmids":["35081355"],"is_preprint":false},{"year":2020,"finding":"SUN1 interacts with both TERB1 and MAJIN (the latter more strongly), and SPDYA recruits CDK2 to SUN1 via the Ringo domain; CDK2 inhibition decreases the SUN1-MAJIN interaction, implicating SPDYA-CDK2 in promoting telomere-NE attachment through the TTM complex.","method":"Co-immunoprecipitation, binding site mapping, CDK2 inhibitor treatment, pulldown assays","journal":"Frontiers in cell and developmental biology","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, Co-IP and pharmacological inhibition without in vivo genetic rescue","pmids":["33015044"],"is_preprint":false}],"current_model":"TERB2 is a central scaffold protein of the meiotic telomere complex (MTC) that forms a 2:2 hetero-tetramer with MAJIN (which binds telomeric DNA and the inner nuclear membrane) and associates 1:1 with TERB1 (which binds TRF1 on telomeres), thereby tethering telomere ends to the nuclear envelope; TRF1 initially recruits the complex but is displaced during pachytene allowing MAJIN-TERB2 to directly bind telomeric DNA, and the entire TERB1-TERB2-MAJIN network cooperates with SUN1 (LINC complex) to transmit cytoskeletal forces for meiotic chromosome movements and homologous pairing."},"narrative":{"teleology":[{"year":2017,"claim":"Establishing the epistatic hierarchy of the telomere–NE attachment pathway: TRF1 directs assembly of the TERB1-TERB2-MAJIN complex, with a specific TERB2-binding domain in TERB1 essential for recruiting TERB2-MAJIN to telomeres and attaching them to the nuclear envelope.","evidence":"Germ-cell-specific Trf1 knockout and domain-specific Terb1 mutations in mouse, Co-IP, cytological analysis","pmids":["29141207"],"confidence":"High","gaps":["Structural basis of TERB1-TERB2 and TERB2-MAJIN interactions not yet resolved","Stoichiometry of the complex unknown","Mechanism of TRF1 displacement at pachytene undefined"]},{"year":2018,"claim":"Resolving the architecture of the meiotic telomere complex: MAJIN-TERB2 forms a 2:2 hetero-tetramer that binds DNA, connected via flexible linkers to 1:1 TERB2-TERB1 units; TRF1 is displaced during pachytene, enabling direct MAJIN-TERB2 DNA binding and formation of a mature attachment plate.","evidence":"Crystal structure of MAJIN-TERB2, X-ray scattering, structured illumination microscopy, biochemical DNA-binding assays","pmids":["30559341"],"confidence":"High","gaps":["Atomic structure of the full tripartite TERB1-TERB2-MAJIN assembly not determined","Signal or mechanism triggering TRF1 displacement at pachytene unknown","How the complex integrates with LINC complex components not addressed"]},{"year":2019,"claim":"Validating TERB2 as the essential bridge in vivo: crystal structures of both TERB1-TERB2 and TERB2-MAJIN subcomplexes combined with interface-disrupting Terb2 knock-in mutations demonstrated that loss of either interaction abolishes telomere–NE attachment, homologous pairing, and orderly synapsis.","evidence":"Crystal structures, mouse Terb2 knock-in point mutations disrupting specific interfaces, cytological meiotic phenotyping","pmids":["30718482"],"confidence":"High","gaps":["Regulation of TERB2 expression or post-translational modification during meiotic progression unknown","Contribution of TERB2 to force transmission through the LINC complex not tested"]},{"year":2020,"claim":"Linking the MTC to force-transducing machinery: SUN1 physically interacts with both TERB1 and MAJIN, and SPDYA-CDK2 promotes the SUN1-MAJIN interaction, suggesting a kinase-regulated coupling of telomere attachment to cytoskeletal forces.","evidence":"Co-immunoprecipitation, binding-site mapping, CDK2 inhibitor treatment, pulldown assays","pmids":["33015044"],"confidence":"Medium","gaps":["No in vivo genetic validation of CDK2-dependent regulation of SUN1-MAJIN binding","Direct phosphorylation targets on MAJIN or SUN1 not identified","Whether TERB2 directly contacts SUN1 not tested"]},{"year":2022,"claim":"Separating telomere attachment from telomere maintenance: the TERB1 MYB domain is dispensable for TERB2-MAJIN recruitment and homologous pairing but instead regulates cohesin enrichment and axial element remodeling at pachytene, suppressing telomere erosion.","evidence":"Terb1 MYB-domain point mutant mice, immunofluorescence, cohesin and axial element cytology, telomere length analysis","pmids":["35081355"],"confidence":"High","gaps":["Whether TERB2-MAJIN plays any role in the cohesin-enrichment or telomere-protection function is untested","Molecular mechanism by which TERB1 MYB controls cohesin dynamics is unknown"]},{"year":null,"claim":"Open question: what triggers TRF1 displacement and the transition from the initial to mature telomere attachment complex, and what post-translational modifications regulate TERB2 function during meiotic progression?","evidence":"","pmids":[],"confidence":"High","gaps":["Signal or kinase activity responsible for TRF1 displacement at pachytene unknown","Post-translational modification landscape of TERB2 uncharacterized","Full atomic structure of the assembled TERB1-TERB2-MAJIN-SUN1 supercomplex not resolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,2]}],"localization":[{"term_id":"GO:0005635","term_label":"nuclear envelope","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[0,1,2]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[0,1,2,3]}],"complexes":["TERB1-TERB2-MAJIN (meiotic telomere complex)"],"partners":["MAJIN","TERB1","TRF1","SUN1"],"other_free_text":[]},"mechanistic_narrative":"TERB2 is a central scaffold protein of the meiotic telomere complex (MTC) that bridges telomere-bound shelterin to the inner nuclear membrane during meiosis. It forms a 2:2 hetero-tetramer with MAJIN, which binds telomeric DNA and anchors to the inner nuclear membrane, while simultaneously forming a 1:1 complex with TERB1, which recruits the complex to telomeres via TRF1; crystal structures of both the TERB2-MAJIN and TERB1-TERB2 subcomplexes define these interfaces, and specific disruption of either interface in mouse knock-in models abolishes telomere–nuclear envelope attachment, causing aberrant homologous pairing and disordered synapsis [PMID:30559341, PMID:30718482]. TRF1 initially recruits the TERB1-TERB2-MAJIN complex to telomeres, but is displaced during pachytene, enabling MAJIN-TERB2 to directly engage telomeric DNA and form a mature attachment plate [PMID:29141207, PMID:30559341]. SUN1 (LINC complex) physically interacts with MAJIN and TERB1, coupling the complex to cytoskeletal forces required for meiotic chromosome movements, with CDK2-SPDYA promoting the SUN1-MAJIN interaction [PMID:33015044]."},"prefetch_data":{"uniprot":{"accession":"Q8NHR7","full_name":"Telomere repeats-binding bouquet formation protein 2","aliases":[],"length_aa":220,"mass_kda":25.3,"function":"Meiosis-specific telomere-associated protein involved in meiotic telomere attachment to the nucleus inner membrane, a crucial step for homologous pairing and synapsis. Component of the MAJIN-TERB1-TERB2 complex, which promotes telomere cap exchange by mediating attachment of telomeric DNA to the inner nuclear membrane and replacement of the protective cap of telomeric chromosomes: in early meiosis, the MAJIN-TERB1-TERB2 complex associates with telomeric DNA and the shelterin/telosome complex. During prophase, the complex matures and promotes release of the shelterin/telosome complex from telomeric DNA","subcellular_location":"Chromosome, telomere; Nucleus inner membrane","url":"https://www.uniprot.org/uniprotkb/Q8NHR7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TERB2","classification":"Not Classified","n_dependent_lines":5,"n_total_lines":1208,"dependency_fraction":0.0041390728476821195},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TERB2","total_profiled":1310},"omim":[{"mim_id":"619646","title":"SPERMATOGENIC FAILURE 60; SPGF60","url":"https://www.omim.org/entry/619646"},{"mim_id":"619645","title":"SPERMATOGENIC FAILURE 59; SPGF59","url":"https://www.omim.org/entry/619645"},{"mim_id":"617332","title":"TELOMERE REPEAT-BINDING BOUQUET FORMATION PROTEIN 1; TERB1","url":"https://www.omim.org/entry/617332"},{"mim_id":"617131","title":"TELOMERE REPEAT-BINDING BOUQUET FORMATION PROTEIN 2; TERB2","url":"https://www.omim.org/entry/617131"},{"mim_id":"617130","title":"MEMBRANE-ANCHORED JUNCTION PROTEIN; MAJIN","url":"https://www.omim.org/entry/617130"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Nucleoli","reliability":"Uncertain"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"testis","ntpm":20.5}],"url":"https://www.proteinatlas.org/search/TERB2"},"hgnc":{"alias_symbol":["MGC33951"],"prev_symbol":["C15orf43"]},"alphafold":{"accession":"Q8NHR7","domains":[{"cath_id":"3.40.50.10190","chopping":"2-108","consensus_level":"medium","plddt":94.7153,"start":2,"end":108}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NHR7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NHR7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NHR7-F1-predicted_aligned_error_v6.png","plddt_mean":71.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TERB2","jax_strain_url":"https://www.jax.org/strain/search?query=TERB2"},"sequence":{"accession":"Q8NHR7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NHR7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NHR7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NHR7"}},"corpus_meta":[{"pmid":"30718482","id":"PMC_30718482","title":"The meiotic TERB1-TERB2-MAJIN complex tethers telomeres to the nuclear envelope.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30718482","citation_count":41,"is_preprint":false},{"pmid":"33211200","id":"PMC_33211200","title":"Disruption of human meiotic telomere complex genes TERB1, TERB2 and MAJIN in men with non-obstructive azoospermia.","date":"2020","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/33211200","citation_count":37,"is_preprint":false},{"pmid":"30559341","id":"PMC_30559341","title":"Structural basis of meiotic telomere attachment to the nuclear envelope by MAJIN-TERB2-TERB1.","date":"2018","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30559341","citation_count":32,"is_preprint":false},{"pmid":"29141207","id":"PMC_29141207","title":"Distinct TERB1 Domains Regulate Different Protein Interactions in Meiotic Telomere Movement.","date":"2017","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/29141207","citation_count":30,"is_preprint":false},{"pmid":"32408858","id":"PMC_32408858","title":"The TERB1-TERB2-MAJIN complex of mouse meiotic telomeres dates back to the common ancestor of metazoans.","date":"2020","source":"BMC evolutionary biology","url":"https://pubmed.ncbi.nlm.nih.gov/32408858","citation_count":17,"is_preprint":false},{"pmid":"33015044","id":"PMC_33015044","title":"Tethering of Telomeres to the Nuclear Envelope Is Mediated by SUN1-MAJIN and Possibly Promoted by SPDYA-CDK2 During Meiosis.","date":"2020","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/33015044","citation_count":15,"is_preprint":false},{"pmid":"35081355","id":"PMC_35081355","title":"The TERB1 MYB domain suppresses telomere erosion in meiotic prophase I.","date":"2022","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/35081355","citation_count":10,"is_preprint":false},{"pmid":"35342767","id":"PMC_35342767","title":"Computational Analysis of the Potential Impact of MTC Complex Missenses SNPs Associated with Male Infertility.","date":"2022","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/35342767","citation_count":4,"is_preprint":false},{"pmid":"38511802","id":"PMC_38511802","title":"Telomeric function and regulation during male meiosis in mice and humans.","date":"2024","source":"Andrology","url":"https://pubmed.ncbi.nlm.nih.gov/38511802","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5428,"output_tokens":1425,"usd":0.018829},"stage2":{"model":"claude-opus-4-6","input_tokens":4642,"output_tokens":1934,"usd":0.10734},"total_usd":0.126169,"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\": \"MAJIN-TERB2 forms a 2:2 hetero-tetramer that binds strongly to DNA and is tethered through long flexible linkers to the inner nuclear membrane and two TRF1-binding 1:1 TERB2-TERB1 complexes; MAJIN-TERB2-TERB1 recruits telomere-bound TRF1, which is then displaced during pachytene, allowing MAJIN-TERB2-TERB1 to bind telomeric DNA and form a mature attachment plate.\",\n      \"method\": \"Crystal structure of MAJIN-TERB2, X-ray and light scattering of wider complexes, structured illumination microscopy, biochemical DNA-binding assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure combined with biochemical and imaging validation in a single rigorous study\",\n      \"pmids\": [\"30559341\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crystal structures of human TERB1-TERB2 and TERB2-MAJIN subcomplexes were resolved; specific disruption of either the TERB1-TERB2 or TERB2-MAJIN interaction in mouse Terb2 abolishes telomere attachment to the nuclear envelope and causes aberrant homologous pairing and disordered synapsis, establishing TERB2 as a central scaffold linking telomeres to the NE via a TERB1-TERB2-MAJIN interaction network.\",\n      \"method\": \"Crystal structure determination, mouse Terb2 knock-in mutations disrupting specific protein-protein interfaces, cytological analysis of meiotic phenotypes\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures combined with in vivo mutagenesis and functional rescue experiments\",\n      \"pmids\": [\"30718482\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TRF1 directs the assembly of the TERB1-TERB2-MAJIN complex; a TERB2-binding (T2B) domain in TERB1 is dispensable for TRF1-TERB1 interaction but essential for TERB1-TERB2 interaction and telomere attachment to the NE; TERB2-MAJIN is required for telomere attachment to the NE downstream of TRF1.\",\n      \"method\": \"Germ-cell-specific Trf1 knockout mouse, domain-specific knockout/mutation analysis, Co-immunoprecipitation, cytological analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with specific domain dissection in mouse models, replicated by subsequent structural studies\",\n      \"pmids\": [\"29141207\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The TERB1 MYB domain is dispensable for telomere localization of TERB1 and the downstream TERB2-MAJIN complex and for homologous pairing, but instead regulates cohesin enrichment and axial element remodeling at the early-to-late pachytene transition, thereby suppressing telomere erosion.\",\n      \"method\": \"Terb1 point mutant mice lacking the MYB domain, immunofluorescence, cytological analysis of cohesin and axial element dynamics, telomere length analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean mouse genetic model with multiple orthogonal readouts establishing TERB2-MAJIN localization downstream of TERB1 MYB\",\n      \"pmids\": [\"35081355\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SUN1 interacts with both TERB1 and MAJIN (the latter more strongly), and SPDYA recruits CDK2 to SUN1 via the Ringo domain; CDK2 inhibition decreases the SUN1-MAJIN interaction, implicating SPDYA-CDK2 in promoting telomere-NE attachment through the TTM complex.\",\n      \"method\": \"Co-immunoprecipitation, binding site mapping, CDK2 inhibitor treatment, pulldown assays\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, Co-IP and pharmacological inhibition without in vivo genetic rescue\",\n      \"pmids\": [\"33015044\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TERB2 is a central scaffold protein of the meiotic telomere complex (MTC) that forms a 2:2 hetero-tetramer with MAJIN (which binds telomeric DNA and the inner nuclear membrane) and associates 1:1 with TERB1 (which binds TRF1 on telomeres), thereby tethering telomere ends to the nuclear envelope; TRF1 initially recruits the complex but is displaced during pachytene allowing MAJIN-TERB2 to directly bind telomeric DNA, and the entire TERB1-TERB2-MAJIN network cooperates with SUN1 (LINC complex) to transmit cytoskeletal forces for meiotic chromosome movements and homologous pairing.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TERB2 is a central scaffold protein of the meiotic telomere complex (MTC) that bridges telomere-bound shelterin to the inner nuclear membrane during meiosis. It forms a 2:2 hetero-tetramer with MAJIN, which binds telomeric DNA and anchors to the inner nuclear membrane, while simultaneously forming a 1:1 complex with TERB1, which recruits the complex to telomeres via TRF1; crystal structures of both the TERB2-MAJIN and TERB1-TERB2 subcomplexes define these interfaces, and specific disruption of either interface in mouse knock-in models abolishes telomere–nuclear envelope attachment, causing aberrant homologous pairing and disordered synapsis [PMID:30559341, PMID:30718482]. TRF1 initially recruits the TERB1-TERB2-MAJIN complex to telomeres, but is displaced during pachytene, enabling MAJIN-TERB2 to directly engage telomeric DNA and form a mature attachment plate [PMID:29141207, PMID:30559341]. SUN1 (LINC complex) physically interacts with MAJIN and TERB1, coupling the complex to cytoskeletal forces required for meiotic chromosome movements, with CDK2-SPDYA promoting the SUN1-MAJIN interaction [PMID:33015044].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Establishing the epistatic hierarchy of the telomere–NE attachment pathway: TRF1 directs assembly of the TERB1-TERB2-MAJIN complex, with a specific TERB2-binding domain in TERB1 essential for recruiting TERB2-MAJIN to telomeres and attaching them to the nuclear envelope.\",\n      \"evidence\": \"Germ-cell-specific Trf1 knockout and domain-specific Terb1 mutations in mouse, Co-IP, cytological analysis\",\n      \"pmids\": [\"29141207\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of TERB1-TERB2 and TERB2-MAJIN interactions not yet resolved\",\n        \"Stoichiometry of the complex unknown\",\n        \"Mechanism of TRF1 displacement at pachytene undefined\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Resolving the architecture of the meiotic telomere complex: MAJIN-TERB2 forms a 2:2 hetero-tetramer that binds DNA, connected via flexible linkers to 1:1 TERB2-TERB1 units; TRF1 is displaced during pachytene, enabling direct MAJIN-TERB2 DNA binding and formation of a mature attachment plate.\",\n      \"evidence\": \"Crystal structure of MAJIN-TERB2, X-ray scattering, structured illumination microscopy, biochemical DNA-binding assays\",\n      \"pmids\": [\"30559341\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Atomic structure of the full tripartite TERB1-TERB2-MAJIN assembly not determined\",\n        \"Signal or mechanism triggering TRF1 displacement at pachytene unknown\",\n        \"How the complex integrates with LINC complex components not addressed\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Validating TERB2 as the essential bridge in vivo: crystal structures of both TERB1-TERB2 and TERB2-MAJIN subcomplexes combined with interface-disrupting Terb2 knock-in mutations demonstrated that loss of either interaction abolishes telomere–NE attachment, homologous pairing, and orderly synapsis.\",\n      \"evidence\": \"Crystal structures, mouse Terb2 knock-in point mutations disrupting specific interfaces, cytological meiotic phenotyping\",\n      \"pmids\": [\"30718482\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Regulation of TERB2 expression or post-translational modification during meiotic progression unknown\",\n        \"Contribution of TERB2 to force transmission through the LINC complex not tested\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linking the MTC to force-transducing machinery: SUN1 physically interacts with both TERB1 and MAJIN, and SPDYA-CDK2 promotes the SUN1-MAJIN interaction, suggesting a kinase-regulated coupling of telomere attachment to cytoskeletal forces.\",\n      \"evidence\": \"Co-immunoprecipitation, binding-site mapping, CDK2 inhibitor treatment, pulldown assays\",\n      \"pmids\": [\"33015044\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No in vivo genetic validation of CDK2-dependent regulation of SUN1-MAJIN binding\",\n        \"Direct phosphorylation targets on MAJIN or SUN1 not identified\",\n        \"Whether TERB2 directly contacts SUN1 not tested\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Separating telomere attachment from telomere maintenance: the TERB1 MYB domain is dispensable for TERB2-MAJIN recruitment and homologous pairing but instead regulates cohesin enrichment and axial element remodeling at pachytene, suppressing telomere erosion.\",\n      \"evidence\": \"Terb1 MYB-domain point mutant mice, immunofluorescence, cohesin and axial element cytology, telomere length analysis\",\n      \"pmids\": [\"35081355\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TERB2-MAJIN plays any role in the cohesin-enrichment or telomere-protection function is untested\",\n        \"Molecular mechanism by which TERB1 MYB controls cohesin dynamics is unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Open question: what triggers TRF1 displacement and the transition from the initial to mature telomere attachment complex, and what post-translational modifications regulate TERB2 function during meiotic progression?\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Signal or kinase activity responsible for TRF1 displacement at pachytene unknown\",\n        \"Post-translational modification landscape of TERB2 uncharacterized\",\n        \"Full atomic structure of the assembled TERB1-TERB2-MAJIN-SUN1 supercomplex not resolved\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005635\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [0, 1, 2, 3]}\n    ],\n    \"complexes\": [\n      \"TERB1-TERB2-MAJIN (meiotic telomere complex)\"\n    ],\n    \"partners\": [\n      \"MAJIN\",\n      \"TERB1\",\n      \"TRF1\",\n      \"SUN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}