{"gene":"SHLD3","run_date":"2026-06-10T07:46:31","timeline":{"discoveries":[{"year":2018,"finding":"SHLD3 (CTC-534A2.2) is a subunit of the shieldin complex (SHLD1-SHLD2-SHLD3-REV7) that localizes to DNA double-strand break sites in a 53BP1- and RIF1-dependent manner, protecting DNA ends from nucleolytic resection to promote non-homologous end-joining and immunoglobulin class-switch recombination.","method":"Co-immunoprecipitation, chromatin immunoprecipitation, genetic knockouts/knockdowns with CSR and resection readouts","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — independently replicated across two concurrent Nature papers (PMID:30022168 and PMID:30046110) using reciprocal Co-IP, cellular localization, and multiple functional assays","pmids":["30022168","30046110","30022158"],"is_preprint":false},{"year":2018,"finding":"Loss of shieldin (including SHLD3) impairs NHEJ, causes hyper-resection of DSB ends, leads to defective immunoglobulin class switching, and causes resistance to PARP inhibition in BRCA1-deficient cells by restoring homologous recombination.","method":"Genetic knockouts and knockdowns with NHEJ efficiency assays, class-switch recombination assays, HR assays, and PARP inhibitor sensitivity measurements","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — replicated across multiple independent labs with multiple functional readouts","pmids":["30022168","30046110","30022158"],"is_preprint":false},{"year":2018,"finding":"Shieldin complex (including SHLD3) interacts with and recruits CST (CTC1-STN1-TEN1), which localizes with Polymerase-α to sites of DNA damage in a 53BP1- and shieldin-dependent manner, mediating fill-in synthesis to control DSB end resection.","method":"Co-immunoprecipitation, immunofluorescence localization, epistasis by depletion with resection and HR readouts","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP plus epistasis experiments, replicated across labs","pmids":["30022158","40178294"],"is_preprint":false},{"year":2019,"finding":"SHLD3 interacts with REV7 through a 'ladle-shaped' REV7-binding domain (RBD) comprising an N-terminal loop and a C-terminal α-helix (αC-helix); both elements are required for high-affinity (low-nanomolar) REV7 binding, and the REV7 'safety belt' region is essential for retaining the SHLD3 RBD.","method":"Crystal structures of REV7-SHLD3 RBD complex at 2.2–2.3 Å resolution, in vitro and in vivo binding analyses, mutagenesis of the αC-helix and N-terminal loop","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus mutagenesis and binding kinetics in a single study","pmids":["31796627"],"is_preprint":false},{"year":2020,"finding":"Crystal structure of the SHLD3-REV7-SHLD2 ternary complex reveals that SHLD3 mediates an unexpected closed (C)-REV7 / open (O)-REV7 conformational dimer; SHLD2 interacts with O-REV7 and the N-terminus of SHLD3 via a β-sheet sandwich; disruption of the REV7 conformational dimer abolishes shieldin assembly and impairs NHEJ.","method":"Crystal structure determination, mutagenesis of the REV7 dimerization interface, NHEJ efficiency assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with mutagenesis and functional NHEJ assay in single rigorous study","pmids":["32332881"],"is_preprint":false},{"year":2020,"finding":"The conserved FXPWFP motif of SHLD3 binds to closed (C)-REV7 and blocks its binding to REV1, thereby excluding shieldin from the REV1/Pol ζ translesion synthesis complex and separating NHEJ from TLS functions.","method":"Crystal structure analysis and in vitro competition/binding assays with mutagenesis","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus in vitro binding competition assay, single lab","pmids":["32332881"],"is_preprint":false},{"year":2021,"finding":"Crystal and cryo-EM structures of SHLD3-REV7 binary and SHLD2-SHLD3-REV7 ternary complexes confirm C-REV7/O-REV7 conformational heterodimerization induced by SHLD3; TRIP13 ATPase disassembles shieldin by inserting the N-terminus of REV7 into its central channel and pulling the unfolded C-REV7 safety-belt through ATP hydrolysis-driven rotatory motions.","method":"Crystal structure determination (SHLD3-REV7 binary and fused SHLD2-SHLD3-REV7 ternary), cryo-EM of SHLD2-SHLD3-REV7-TRIP13 complex, ATPase and disassembly assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — independent crystal + cryo-EM structural determination with functional ATPase validation, largely replicating and extending PMID:32332881","pmids":["33597306"],"is_preprint":false},{"year":2021,"finding":"MAD2L2 (REV7) dimerization mediated by SHLD2 accelerates the MAD2L2-SHLD3 interaction and is required for proper shieldin assembly; the presence of SHLD3 together with MAD2L2 dimerization enables shieldin to interact with the TRIP13 ATPase, which drives shieldin disassembly and regulates DNA repair pathway choice.","method":"Dimerization-defective MAD2L2 mutants, Co-immunoprecipitation, NHEJ assays, PARP inhibitor sensitivity assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP with multiple mutants plus functional NHEJ and resection assays, single lab","pmids":["34521823"],"is_preprint":false},{"year":2020,"finding":"TRIP13 promotes homologous recombination by remodeling REV7, causing its dissociation from the shieldin subunit SHLD3; p31comet facilitates this process by mediating the TRIP13-REV7 interaction and promoting extraction of REV7 from chromatin, thereby causing PARP inhibitor resistance.","method":"Co-immunoprecipitation, chromatin fractionation, HR and PARP inhibitor resistance assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus chromatin fractionation and functional assays, single lab","pmids":["33051298"],"is_preprint":false},{"year":2022,"finding":"CHAMP1 binds directly to the REV7 seatbelt domain (the same interface used by SHLD3) and competes with SHLD3 binding, reducing shieldin complex levels and increasing DSB end resection to promote homologous recombination.","method":"Direct binding assays, Co-immunoprecipitation, resection assays, HR reporter assays","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding plus Co-IP and functional HR assays, single lab","pmids":["36044844"],"is_preprint":false},{"year":2023,"finding":"AlphaFold2-Multimer predicted and in vitro pulldown plus cellular assays confirmed a direct physical interaction between the HEAT-repeat domain of RIF1 and the eIF4E-like domain of SHLD3; this RIF1-SHLD3 interaction is essential for shieldin recruitment to DSB sites and for antibody class switch recombination and PARP inhibitor sensitivity.","method":"AlphaFold2-Multimer structural prediction, in vitro pulldown assays, cellular co-immunoprecipitation, shieldin recruitment (focus formation) assays, CSR assays, PARP inhibitor sensitivity assays","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — AF2 prediction validated by in vitro pulldown and multiple functional cellular assays, single lab but orthogonal methods","pmids":["37306046"],"is_preprint":false},{"year":2023,"finding":"SHLD3 contains a promiscuous DNA-binding domain; its interaction with the first REV7 molecule is remarkably slow (rate-limiting step in shieldin assembly), whereas the subsequent interaction with SHLD2 and the second REV7 molecule is fast and does not require structural remodeling.","method":"In vitro biochemical reconstitution, kinetic binding measurements, DNA binding assays","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with kinetic analysis, single lab","pmids":["37031298"],"is_preprint":false},{"year":2018,"finding":"Shieldin is essential for REV7-dependent DNA end-protection and NHEJ during class-switch recombination but is dispensable for REV7-dependent interstrand cross-link repair, demonstrating that SHLD3-containing shieldin explains the context-specificity of the 53BP1 pathway.","method":"Genetic knockouts, class-switch recombination assays, interstrand crosslink repair assays, epistasis analysis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with multiple functional readouts, replicated across independent labs","pmids":["30046110"],"is_preprint":false},{"year":2025,"finding":"CTC1 (CST complex) and SHLD1 are epistatic in preventing exacerbated DNA end resection and genetic instability during class-switch recombination; a SHLD1 mutant defective in CST binding (SHLD1ΔLDLP) is fully proficient for class switching, demonstrating that the direct SHLD1-CTC1 interaction through this motif is dispensable for promoting CSR.","method":"CRISPR knockout B-cell lines, CSR assays, resection assays, chromosome break/translocation analysis, complementation with SHLD1 mutant","journal":"European journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with multiple functional readouts, single lab","pmids":["40178294"],"is_preprint":false}],"current_model":"SHLD3 is the apical subunit of the shieldin complex (SHLD3-REV7-SHLD2-SHLD1) that acts downstream of 53BP1-RIF1 to protect DNA double-strand break ends from nucleolytic resection: SHLD3 recruits shieldin to DSB sites via a direct interaction between its eIF4E-like domain and the HEAT-repeat domain of RIF1, binds REV7 through a bipartite RBD (N-terminal loop + αC-helix engaging the REV7 safety belt) to nucleate a C-REV7/O-REV7 conformational dimer that organizes the full complex, contains a promiscuous DNA-binding domain, and uses its conserved FXPWFP motif to compete with REV1 binding to REV7 thereby segregating shieldin/NHEJ activity from TLS; shieldin in turn recruits CST-Polα for fill-in synthesis, and TRIP13-mediated disassembly of the SHLD3-REV7 interface (facilitated by p31comet and CHAMP1 competition) shifts repair toward homologous recombination."},"narrative":{"mechanistic_narrative":"SHLD3 is the apical subunit of the shieldin complex (SHLD3-REV7-SHLD2-SHLD1), which acts downstream of 53BP1 and RIF1 to protect DNA double-strand break ends from nucleolytic resection, thereby promoting non-homologous end-joining and immunoglobulin class-switch recombination [PMID:30022168, PMID:30046110, PMID:30022158]. SHLD3 recruits shieldin to break sites through a direct interaction between its eIF4E-like domain and the HEAT-repeat domain of RIF1, an interaction required for focus formation, class switching, and PARP inhibitor sensitivity [PMID:37306046]. Through a bipartite, ladle-shaped REV7-binding domain comprising an N-terminal loop and a C-terminal αC-helix that engages the REV7 'safety belt', SHLD3 binds REV7 with low-nanomolar affinity and nucleates a closed-REV7/open-REV7 conformational dimer that organizes assembly of the full complex onto SHLD2 [PMID:31796627, PMID:32332881, PMID:33597306]. The conserved FXPWFP motif of SHLD3 binds closed-REV7 and blocks REV1 engagement, segregating shieldin/NHEJ activity from REV1/Polζ translesion synthesis [PMID:32332881]. Once assembled, shieldin recruits CST-Polα to mediate fill-in synthesis that limits resection [PMID:30022158, PMID:40178294], while TRIP13 ATPase-driven disassembly of the SHLD3-REV7 interface—facilitated by p31comet and antagonized by CHAMP1 competition for the REV7 seatbelt—extracts REV7 and shifts repair toward homologous recombination [PMID:33597306, PMID:33051298, PMID:36044844]. Loss of SHLD3-containing shieldin causes hyper-resection, defective class switching, and restoration of HR that confers PARP inhibitor resistance in BRCA1-deficient cells [PMID:30022168, PMID:30046110, PMID:30022158].","teleology":[{"year":2018,"claim":"Established SHLD3 as a bona fide DSB-repair factor by defining it as a shieldin subunit recruited downstream of 53BP1-RIF1 to protect DNA ends and promote NHEJ.","evidence":"Co-IP, ChIP, and genetic knockouts with class-switch recombination and resection readouts in cells","pmids":["30022168","30046110","30022158"],"confidence":"High","gaps":["Did not resolve the atomic basis of SHLD3 interactions within the complex","Mechanism of how end-protection is enforced was not defined"]},{"year":2018,"claim":"Showed that loss of SHLD3-containing shieldin has therapeutic relevance by restoring HR and conferring PARP inhibitor resistance in BRCA1-deficient cells.","evidence":"Genetic knockouts/knockdowns with NHEJ, CSR, HR, and PARP inhibitor sensitivity assays","pmids":["30022168","30046110","30022158"],"confidence":"High","gaps":["Did not identify the downstream effector that physically limits resection"]},{"year":2018,"claim":"Identified the effector that executes end-protection, linking shieldin to CST-Polα fill-in synthesis at break sites.","evidence":"Co-IP, immunofluorescence localization, and depletion epistasis with resection/HR readouts","pmids":["30022158","40178294"],"confidence":"High","gaps":["Direct SHLD3-CST contact versus indirect recruitment not delineated","Stoichiometry of CST recruitment unresolved"]},{"year":2018,"claim":"Defined context-specificity of the 53BP1 pathway by showing SHLD3-containing shieldin is required for REV7-dependent NHEJ/CSR but dispensable for interstrand cross-link repair.","evidence":"Genetic knockouts with CSR, ICL repair, and epistasis analysis","pmids":["30046110"],"confidence":"High","gaps":["Molecular basis for the differential REV7 function across pathways not established"]},{"year":2019,"claim":"Resolved how SHLD3 physically engages REV7, defining a bipartite ladle-shaped RBD that achieves high-affinity binding via the REV7 safety belt.","evidence":"Crystal structures of REV7-SHLD3 RBD at 2.2–2.3 Å with mutagenesis and binding kinetics","pmids":["31796627"],"confidence":"High","gaps":["Did not show how the binary interaction scales to the full complex","Functional consequence of RBD mutants in cells not fully mapped"]},{"year":2020,"claim":"Revealed the organizing principle of shieldin assembly: SHLD3 nucleates a closed/open REV7 conformational dimer onto which SHLD2 docks, a dimer required for NHEJ.","evidence":"Crystal structure of SHLD3-REV7-SHLD2 ternary complex with dimer-interface mutagenesis and NHEJ assays","pmids":["32332881"],"confidence":"High","gaps":["Kinetics and rate-limiting steps of assembly not addressed","How the dimer is disassembled was not resolved here"]},{"year":2020,"claim":"Explained how shieldin/NHEJ is insulated from translesion synthesis, showing the SHLD3 FXPWFP motif occupies closed-REV7 and blocks REV1.","evidence":"Crystal structure analysis with in vitro competition/binding assays and mutagenesis","pmids":["32332881"],"confidence":"High","gaps":["In vivo competition dynamics between REV1 and SHLD3 not quantified"]},{"year":2020,"claim":"Identified the disassembly mechanism that switches repair toward HR: TRIP13 remodels REV7 to dissociate it from SHLD3, with p31comet bridging TRIP13-REV7 and driving PARPi resistance.","evidence":"Co-IP, chromatin fractionation, and HR/PARP inhibitor resistance assays","pmids":["33051298"],"confidence":"Medium","gaps":["Single lab without structural validation of the remodeling intermediate","Quantitative contribution of p31comet versus TRIP13 alone unclear"]},{"year":2021,"claim":"Provided structural mechanism for TRIP13-driven disassembly, showing it threads the REV7 N-terminus into its channel and pulls the unfolded safety belt via ATP hydrolysis.","evidence":"Crystal and cryo-EM structures of binary/ternary and TRIP13-bound complexes with ATPase and disassembly assays","pmids":["33597306"],"confidence":"High","gaps":["Cellular regulation of TRIP13 engagement timing not defined"]},{"year":2021,"claim":"Linked REV7 dimerization to assembly kinetics and pathway-choice regulation, showing SHLD2-mediated dimerization accelerates the MAD2L2-SHLD3 interaction and enables TRIP13-driven disassembly.","evidence":"Dimerization-defective MAD2L2 mutants, Co-IP, NHEJ and PARP inhibitor sensitivity assays","pmids":["34521823"],"confidence":"High","gaps":["Upstream signals controlling the assembly/disassembly balance not identified"]},{"year":2022,"claim":"Identified CHAMP1 as a competitive antagonist that vacates the SHLD3-binding interface on REV7, lowering shieldin levels and promoting HR.","evidence":"Direct binding assays, Co-IP, resection and HR reporter assays","pmids":["36044844"],"confidence":"Medium","gaps":["Single lab; physiological conditions favoring CHAMP1 over SHLD3 not defined","Interplay with TRIP13-mediated disassembly unresolved"]},{"year":2023,"claim":"Defined the recruitment receptor for shieldin, demonstrating a direct RIF1 HEAT-repeat / SHLD3 eIF4E-like domain interaction essential for focus formation, CSR, and PARPi sensitivity.","evidence":"AlphaFold2-Multimer prediction validated by in vitro pulldown and multiple cellular functional assays","pmids":["37306046"],"confidence":"High","gaps":["High-resolution experimental structure of the RIF1-SHLD3 interface not determined","Regulation of this contact during the cell cycle not addressed"]},{"year":2023,"claim":"Established the kinetic logic of assembly through reconstitution, showing SHLD3-REV7 binding is the slow rate-limiting step and identifying a promiscuous SHLD3 DNA-binding domain.","evidence":"In vitro biochemical reconstitution, kinetic binding measurements, and DNA binding assays","pmids":["37031298"],"confidence":"Medium","gaps":["Single lab; functional role of SHLD3 DNA binding in cells not demonstrated","Sequence/structure determinants of DNA binding specificity not defined"]},{"year":2025,"claim":"Refined the role of the shieldin-CST axis in immunity, showing CTC1 and SHLD1 are epistatic in preventing exacerbated resection but that the direct SHLD1-CTC1 motif is dispensable for class switching.","evidence":"CRISPR knockout B-cell lines with CSR, resection, chromosome break analysis and mutant complementation","pmids":["40178294"],"confidence":"Medium","gaps":["Mechanism by which CST acts on resection independent of direct SHLD1 binding unresolved","SHLD3-specific contribution to this axis not isolated"]},{"year":null,"claim":"How the assembly/disassembly equilibrium of SHLD3-nucleated shieldin is governed in vivo across the cell cycle and in response to DNA-damage signaling remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No defined upstream signal triggering TRIP13 or CHAMP1 antagonism of SHLD3-REV7","Functional significance of the SHLD3 DNA-binding domain in cells undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,4,10]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[11]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[0,8]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[12,13]}],"complexes":["shieldin (SHLD3-REV7-SHLD2-SHLD1)"],"partners":["REV7","SHLD2","RIF1","CHAMP1","TRIP13","CTC1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6ZNX1","full_name":"Shieldin complex subunit 3","aliases":["REV7-interacting novel NHEJ regulator 1","Shield complex subunit 3"],"length_aa":250,"mass_kda":28.8,"function":"Component of the shieldin complex, which plays an important role in repair of DNA double-stranded breaks (DSBs). During G1 and S phase of the cell cycle, the complex functions downstream of TP53BP1 to promote non-homologous end joining (NHEJ) and suppress DNA end resection. Mediates various NHEJ-dependent processes including immunoglobulin class-switch recombination, and fusion of unprotected telomeres","subcellular_location":"Chromosome","url":"https://www.uniprot.org/uniprotkb/Q6ZNX1/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SHLD3","classification":"Not Classified","n_dependent_lines":7,"n_total_lines":70,"dependency_fraction":0.1},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SHLD3","total_profiled":1310},"omim":[{"mim_id":"621423","title":"TRAFFICKING PROTEIN PARTICLE COMPLEX, SUBUNIT 13; TRAPPC13","url":"https://www.omim.org/entry/621423"},{"mim_id":"618030","title":"SHIELD COMPLEX, SUBUNIT 3; SHLD3","url":"https://www.omim.org/entry/618030"},{"mim_id":"618029","title":"SHIELD COMPLEX, SUBUNIT 2; SHLD2","url":"https://www.omim.org/entry/618029"},{"mim_id":"618028","title":"SHIELD COMPLEX, SUBUNIT 1; SHLD1","url":"https://www.omim.org/entry/618028"},{"mim_id":"605230","title":"TUMOR PROTEIN p53-BINDING PROTEIN 1; TP53BP1","url":"https://www.omim.org/entry/605230"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Nucleoli","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"bone marrow","ntpm":16.5}],"url":"https://www.proteinatlas.org/search/SHLD3"},"hgnc":{"alias_symbol":["AC008560.1","FLJ26957","CTC-534A2.2","RINN1"],"prev_symbol":[]},"alphafold":{"accession":"Q6ZNX1","domains":[{"cath_id":"3.30.70,3.30.70","chopping":"164-250","consensus_level":"high","plddt":90.9841,"start":164,"end":250}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZNX1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZNX1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZNX1-F1-predicted_aligned_error_v6.png","plddt_mean":78.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SHLD3","jax_strain_url":"https://www.jax.org/strain/search?query=SHLD3"},"sequence":{"accession":"Q6ZNX1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6ZNX1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6ZNX1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZNX1"}},"corpus_meta":[{"pmid":"30022168","id":"PMC_30022168","title":"The shieldin complex mediates 53BP1-dependent DNA repair.","date":"2018","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/30022168","citation_count":505,"is_preprint":false},{"pmid":"30022158","id":"PMC_30022158","title":"53BP1-RIF1-shieldin counteracts DSB resection through CST- and Polα-dependent fill-in.","date":"2018","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/30022158","citation_count":356,"is_preprint":false},{"pmid":"30046110","id":"PMC_30046110","title":"53BP1 cooperation with the REV7-shieldin complex underpins DNA structure-specific NHEJ.","date":"2018","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/30046110","citation_count":254,"is_preprint":false},{"pmid":"30948458","id":"PMC_30948458","title":"Shieldin - the protector of DNA ends.","date":"2019","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/30948458","citation_count":188,"is_preprint":false},{"pmid":"32332881","id":"PMC_32332881","title":"Molecular basis for assembly of the shieldin complex and its implications for NHEJ.","date":"2020","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/32332881","citation_count":41,"is_preprint":false},{"pmid":"34521823","id":"PMC_34521823","title":"MAD2L2 dimerization and TRIP13 control shieldin activity in DNA repair.","date":"2021","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/34521823","citation_count":34,"is_preprint":false},{"pmid":"33051298","id":"PMC_33051298","title":"p31comet promotes homologous recombination by inactivating REV7 through the TRIP13 ATPase.","date":"2020","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/33051298","citation_count":30,"is_preprint":false},{"pmid":"36044844","id":"PMC_36044844","title":"CHAMP1 binds to REV7/FANCV and promotes homologous recombination repair.","date":"2022","source":"Cell 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France)","url":"https://pubmed.ncbi.nlm.nih.gov/38678617","citation_count":1,"is_preprint":false},{"pmid":"40178294","id":"PMC_40178294","title":"CST Is Epistatic With Shieldin to Limit DNA Double-Strand Break End Resection and Promote Repair During Igh Class Switch Recombination.","date":"2025","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/40178294","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10711,"output_tokens":3509,"usd":0.042384,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11050,"output_tokens":4254,"usd":0.0808,"stage2_stop_reason":"end_turn"},"total_usd":0.123184,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2018,\n      \"finding\": \"SHLD3 (CTC-534A2.2) is a subunit of the shieldin complex (SHLD1-SHLD2-SHLD3-REV7) that localizes to DNA double-strand break sites in a 53BP1- and RIF1-dependent manner, protecting DNA ends from nucleolytic resection to promote non-homologous end-joining and immunoglobulin class-switch recombination.\",\n      \"method\": \"Co-immunoprecipitation, chromatin immunoprecipitation, genetic knockouts/knockdowns with CSR and resection readouts\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — independently replicated across two concurrent Nature papers (PMID:30022168 and PMID:30046110) using reciprocal Co-IP, cellular localization, and multiple functional assays\",\n      \"pmids\": [\"30022168\", \"30046110\", \"30022158\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Loss of shieldin (including SHLD3) impairs NHEJ, causes hyper-resection of DSB ends, leads to defective immunoglobulin class switching, and causes resistance to PARP inhibition in BRCA1-deficient cells by restoring homologous recombination.\",\n      \"method\": \"Genetic knockouts and knockdowns with NHEJ efficiency assays, class-switch recombination assays, HR assays, and PARP inhibitor sensitivity measurements\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — replicated across multiple independent labs with multiple functional readouts\",\n      \"pmids\": [\"30022168\", \"30046110\", \"30022158\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Shieldin complex (including SHLD3) interacts with and recruits CST (CTC1-STN1-TEN1), which localizes with Polymerase-α to sites of DNA damage in a 53BP1- and shieldin-dependent manner, mediating fill-in synthesis to control DSB end resection.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence localization, epistasis by depletion with resection and HR readouts\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP plus epistasis experiments, replicated across labs\",\n      \"pmids\": [\"30022158\", \"40178294\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SHLD3 interacts with REV7 through a 'ladle-shaped' REV7-binding domain (RBD) comprising an N-terminal loop and a C-terminal α-helix (αC-helix); both elements are required for high-affinity (low-nanomolar) REV7 binding, and the REV7 'safety belt' region is essential for retaining the SHLD3 RBD.\",\n      \"method\": \"Crystal structures of REV7-SHLD3 RBD complex at 2.2–2.3 Å resolution, in vitro and in vivo binding analyses, mutagenesis of the αC-helix and N-terminal loop\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus mutagenesis and binding kinetics in a single study\",\n      \"pmids\": [\"31796627\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Crystal structure of the SHLD3-REV7-SHLD2 ternary complex reveals that SHLD3 mediates an unexpected closed (C)-REV7 / open (O)-REV7 conformational dimer; SHLD2 interacts with O-REV7 and the N-terminus of SHLD3 via a β-sheet sandwich; disruption of the REV7 conformational dimer abolishes shieldin assembly and impairs NHEJ.\",\n      \"method\": \"Crystal structure determination, mutagenesis of the REV7 dimerization interface, NHEJ efficiency assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with mutagenesis and functional NHEJ assay in single rigorous study\",\n      \"pmids\": [\"32332881\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The conserved FXPWFP motif of SHLD3 binds to closed (C)-REV7 and blocks its binding to REV1, thereby excluding shieldin from the REV1/Pol ζ translesion synthesis complex and separating NHEJ from TLS functions.\",\n      \"method\": \"Crystal structure analysis and in vitro competition/binding assays with mutagenesis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus in vitro binding competition assay, single lab\",\n      \"pmids\": [\"32332881\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Crystal and cryo-EM structures of SHLD3-REV7 binary and SHLD2-SHLD3-REV7 ternary complexes confirm C-REV7/O-REV7 conformational heterodimerization induced by SHLD3; TRIP13 ATPase disassembles shieldin by inserting the N-terminus of REV7 into its central channel and pulling the unfolded C-REV7 safety-belt through ATP hydrolysis-driven rotatory motions.\",\n      \"method\": \"Crystal structure determination (SHLD3-REV7 binary and fused SHLD2-SHLD3-REV7 ternary), cryo-EM of SHLD2-SHLD3-REV7-TRIP13 complex, ATPase and disassembly assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — independent crystal + cryo-EM structural determination with functional ATPase validation, largely replicating and extending PMID:32332881\",\n      \"pmids\": [\"33597306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MAD2L2 (REV7) dimerization mediated by SHLD2 accelerates the MAD2L2-SHLD3 interaction and is required for proper shieldin assembly; the presence of SHLD3 together with MAD2L2 dimerization enables shieldin to interact with the TRIP13 ATPase, which drives shieldin disassembly and regulates DNA repair pathway choice.\",\n      \"method\": \"Dimerization-defective MAD2L2 mutants, Co-immunoprecipitation, NHEJ assays, PARP inhibitor sensitivity assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP with multiple mutants plus functional NHEJ and resection assays, single lab\",\n      \"pmids\": [\"34521823\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TRIP13 promotes homologous recombination by remodeling REV7, causing its dissociation from the shieldin subunit SHLD3; p31comet facilitates this process by mediating the TRIP13-REV7 interaction and promoting extraction of REV7 from chromatin, thereby causing PARP inhibitor resistance.\",\n      \"method\": \"Co-immunoprecipitation, chromatin fractionation, HR and PARP inhibitor resistance assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus chromatin fractionation and functional assays, single lab\",\n      \"pmids\": [\"33051298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CHAMP1 binds directly to the REV7 seatbelt domain (the same interface used by SHLD3) and competes with SHLD3 binding, reducing shieldin complex levels and increasing DSB end resection to promote homologous recombination.\",\n      \"method\": \"Direct binding assays, Co-immunoprecipitation, resection assays, HR reporter assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding plus Co-IP and functional HR assays, single lab\",\n      \"pmids\": [\"36044844\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"AlphaFold2-Multimer predicted and in vitro pulldown plus cellular assays confirmed a direct physical interaction between the HEAT-repeat domain of RIF1 and the eIF4E-like domain of SHLD3; this RIF1-SHLD3 interaction is essential for shieldin recruitment to DSB sites and for antibody class switch recombination and PARP inhibitor sensitivity.\",\n      \"method\": \"AlphaFold2-Multimer structural prediction, in vitro pulldown assays, cellular co-immunoprecipitation, shieldin recruitment (focus formation) assays, CSR assays, PARP inhibitor sensitivity assays\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — AF2 prediction validated by in vitro pulldown and multiple functional cellular assays, single lab but orthogonal methods\",\n      \"pmids\": [\"37306046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SHLD3 contains a promiscuous DNA-binding domain; its interaction with the first REV7 molecule is remarkably slow (rate-limiting step in shieldin assembly), whereas the subsequent interaction with SHLD2 and the second REV7 molecule is fast and does not require structural remodeling.\",\n      \"method\": \"In vitro biochemical reconstitution, kinetic binding measurements, DNA binding assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with kinetic analysis, single lab\",\n      \"pmids\": [\"37031298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Shieldin is essential for REV7-dependent DNA end-protection and NHEJ during class-switch recombination but is dispensable for REV7-dependent interstrand cross-link repair, demonstrating that SHLD3-containing shieldin explains the context-specificity of the 53BP1 pathway.\",\n      \"method\": \"Genetic knockouts, class-switch recombination assays, interstrand crosslink repair assays, epistasis analysis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with multiple functional readouts, replicated across independent labs\",\n      \"pmids\": [\"30046110\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CTC1 (CST complex) and SHLD1 are epistatic in preventing exacerbated DNA end resection and genetic instability during class-switch recombination; a SHLD1 mutant defective in CST binding (SHLD1ΔLDLP) is fully proficient for class switching, demonstrating that the direct SHLD1-CTC1 interaction through this motif is dispensable for promoting CSR.\",\n      \"method\": \"CRISPR knockout B-cell lines, CSR assays, resection assays, chromosome break/translocation analysis, complementation with SHLD1 mutant\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with multiple functional readouts, single lab\",\n      \"pmids\": [\"40178294\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SHLD3 is the apical subunit of the shieldin complex (SHLD3-REV7-SHLD2-SHLD1) that acts downstream of 53BP1-RIF1 to protect DNA double-strand break ends from nucleolytic resection: SHLD3 recruits shieldin to DSB sites via a direct interaction between its eIF4E-like domain and the HEAT-repeat domain of RIF1, binds REV7 through a bipartite RBD (N-terminal loop + αC-helix engaging the REV7 safety belt) to nucleate a C-REV7/O-REV7 conformational dimer that organizes the full complex, contains a promiscuous DNA-binding domain, and uses its conserved FXPWFP motif to compete with REV1 binding to REV7 thereby segregating shieldin/NHEJ activity from TLS; shieldin in turn recruits CST-Polα for fill-in synthesis, and TRIP13-mediated disassembly of the SHLD3-REV7 interface (facilitated by p31comet and CHAMP1 competition) shifts repair toward homologous recombination.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SHLD3 is the apical subunit of the shieldin complex (SHLD3-REV7-SHLD2-SHLD1), which acts downstream of 53BP1 and RIF1 to protect DNA double-strand break ends from nucleolytic resection, thereby promoting non-homologous end-joining and immunoglobulin class-switch recombination [#0, #1]. SHLD3 recruits shieldin to break sites through a direct interaction between its eIF4E-like domain and the HEAT-repeat domain of RIF1, an interaction required for focus formation, class switching, and PARP inhibitor sensitivity [#10]. Through a bipartite, ladle-shaped REV7-binding domain comprising an N-terminal loop and a C-terminal \\u03b1C-helix that engages the REV7 'safety belt', SHLD3 binds REV7 with low-nanomolar affinity and nucleates a closed-REV7/open-REV7 conformational dimer that organizes assembly of the full complex onto SHLD2 [#3, #4, #6]. The conserved FXPWFP motif of SHLD3 binds closed-REV7 and blocks REV1 engagement, segregating shieldin/NHEJ activity from REV1/Pol\\u03b6 translesion synthesis [#5]. Once assembled, shieldin recruits CST-Pol\\u03b1 to mediate fill-in synthesis that limits resection [#2], while TRIP13 ATPase-driven disassembly of the SHLD3-REV7 interface\\u2014facilitated by p31comet and antagonized by CHAMP1 competition for the REV7 seatbelt\\u2014extracts REV7 and shifts repair toward homologous recombination [#6, #8, #9]. Loss of SHLD3-containing shieldin causes hyper-resection, defective class switching, and restoration of HR that confers PARP inhibitor resistance in BRCA1-deficient cells [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Established SHLD3 as a bona fide DSB-repair factor by defining it as a shieldin subunit recruited downstream of 53BP1-RIF1 to protect DNA ends and promote NHEJ.\",\n      \"evidence\": \"Co-IP, ChIP, and genetic knockouts with class-switch recombination and resection readouts in cells\",\n      \"pmids\": [\"30022168\", \"30046110\", \"30022158\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the atomic basis of SHLD3 interactions within the complex\", \"Mechanism of how end-protection is enforced was not defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Showed that loss of SHLD3-containing shieldin has therapeutic relevance by restoring HR and conferring PARP inhibitor resistance in BRCA1-deficient cells.\",\n      \"evidence\": \"Genetic knockouts/knockdowns with NHEJ, CSR, HR, and PARP inhibitor sensitivity assays\",\n      \"pmids\": [\"30022168\", \"30046110\", \"30022158\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the downstream effector that physically limits resection\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identified the effector that executes end-protection, linking shieldin to CST-Pol\\u03b1 fill-in synthesis at break sites.\",\n      \"evidence\": \"Co-IP, immunofluorescence localization, and depletion epistasis with resection/HR readouts\",\n      \"pmids\": [\"30022158\", \"40178294\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct SHLD3-CST contact versus indirect recruitment not delineated\", \"Stoichiometry of CST recruitment unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined context-specificity of the 53BP1 pathway by showing SHLD3-containing shieldin is required for REV7-dependent NHEJ/CSR but dispensable for interstrand cross-link repair.\",\n      \"evidence\": \"Genetic knockouts with CSR, ICL repair, and epistasis analysis\",\n      \"pmids\": [\"30046110\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis for the differential REV7 function across pathways not established\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Resolved how SHLD3 physically engages REV7, defining a bipartite ladle-shaped RBD that achieves high-affinity binding via the REV7 safety belt.\",\n      \"evidence\": \"Crystal structures of REV7-SHLD3 RBD at 2.2\\u20132.3 \\u00c5 with mutagenesis and binding kinetics\",\n      \"pmids\": [\"31796627\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not show how the binary interaction scales to the full complex\", \"Functional consequence of RBD mutants in cells not fully mapped\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Revealed the organizing principle of shieldin assembly: SHLD3 nucleates a closed/open REV7 conformational dimer onto which SHLD2 docks, a dimer required for NHEJ.\",\n      \"evidence\": \"Crystal structure of SHLD3-REV7-SHLD2 ternary complex with dimer-interface mutagenesis and NHEJ assays\",\n      \"pmids\": [\"32332881\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinetics and rate-limiting steps of assembly not addressed\", \"How the dimer is disassembled was not resolved here\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Explained how shieldin/NHEJ is insulated from translesion synthesis, showing the SHLD3 FXPWFP motif occupies closed-REV7 and blocks REV1.\",\n      \"evidence\": \"Crystal structure analysis with in vitro competition/binding assays and mutagenesis\",\n      \"pmids\": [\"32332881\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo competition dynamics between REV1 and SHLD3 not quantified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified the disassembly mechanism that switches repair toward HR: TRIP13 remodels REV7 to dissociate it from SHLD3, with p31comet bridging TRIP13-REV7 and driving PARPi resistance.\",\n      \"evidence\": \"Co-IP, chromatin fractionation, and HR/PARP inhibitor resistance assays\",\n      \"pmids\": [\"33051298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab without structural validation of the remodeling intermediate\", \"Quantitative contribution of p31comet versus TRIP13 alone unclear\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Provided structural mechanism for TRIP13-driven disassembly, showing it threads the REV7 N-terminus into its channel and pulls the unfolded safety belt via ATP hydrolysis.\",\n      \"evidence\": \"Crystal and cryo-EM structures of binary/ternary and TRIP13-bound complexes with ATPase and disassembly assays\",\n      \"pmids\": [\"33597306\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cellular regulation of TRIP13 engagement timing not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Linked REV7 dimerization to assembly kinetics and pathway-choice regulation, showing SHLD2-mediated dimerization accelerates the MAD2L2-SHLD3 interaction and enables TRIP13-driven disassembly.\",\n      \"evidence\": \"Dimerization-defective MAD2L2 mutants, Co-IP, NHEJ and PARP inhibitor sensitivity assays\",\n      \"pmids\": [\"34521823\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream signals controlling the assembly/disassembly balance not identified\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified CHAMP1 as a competitive antagonist that vacates the SHLD3-binding interface on REV7, lowering shieldin levels and promoting HR.\",\n      \"evidence\": \"Direct binding assays, Co-IP, resection and HR reporter assays\",\n      \"pmids\": [\"36044844\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab; physiological conditions favoring CHAMP1 over SHLD3 not defined\", \"Interplay with TRIP13-mediated disassembly unresolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined the recruitment receptor for shieldin, demonstrating a direct RIF1 HEAT-repeat / SHLD3 eIF4E-like domain interaction essential for focus formation, CSR, and PARPi sensitivity.\",\n      \"evidence\": \"AlphaFold2-Multimer prediction validated by in vitro pulldown and multiple cellular functional assays\",\n      \"pmids\": [\"37306046\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution experimental structure of the RIF1-SHLD3 interface not determined\", \"Regulation of this contact during the cell cycle not addressed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established the kinetic logic of assembly through reconstitution, showing SHLD3-REV7 binding is the slow rate-limiting step and identifying a promiscuous SHLD3 DNA-binding domain.\",\n      \"evidence\": \"In vitro biochemical reconstitution, kinetic binding measurements, and DNA binding assays\",\n      \"pmids\": [\"37031298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab; functional role of SHLD3 DNA binding in cells not demonstrated\", \"Sequence/structure determinants of DNA binding specificity not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Refined the role of the shieldin-CST axis in immunity, showing CTC1 and SHLD1 are epistatic in preventing exacerbated resection but that the direct SHLD1-CTC1 motif is dispensable for class switching.\",\n      \"evidence\": \"CRISPR knockout B-cell lines with CSR, resection, chromosome break analysis and mutant complementation\",\n      \"pmids\": [\"40178294\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which CST acts on resection independent of direct SHLD1 binding unresolved\", \"SHLD3-specific contribution to this axis not isolated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the assembly/disassembly equilibrium of SHLD3-nucleated shieldin is governed in vivo across the cell cycle and in response to DNA-damage signaling remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No defined upstream signal triggering TRIP13 or CHAMP1 antagonism of SHLD3-REV7\", \"Functional significance of the SHLD3 DNA-binding domain in cells undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 4, 10]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [0, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [12, 13]}\n    ],\n    \"complexes\": [\"shieldin (SHLD3-REV7-SHLD2-SHLD1)\"],\n    \"partners\": [\"REV7\", \"SHLD2\", \"RIF1\", \"CHAMP1\", \"TRIP13\", \"CTC1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}