{"gene":"TDP2","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2000,"finding":"TTRAP (TDP2) associates with CD40 cytoplasmic domain, TNF-R75, CD30, and TNF receptor-associated factors (TRAFs), with highest affinity for TRAF6; it inhibits NF-κB transcriptional activation downstream of CD40, TNF-R75, and PMA, but not downstream of NIK, IKKα, or P65/RelA, placing it upstream of these kinases","method":"Yeast two-hybrid, co-immunoprecipitation, dose-dependent reporter assay in transfected cells","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assays (Y2H + Co-IP) plus functional reporter assay placing TDP2 upstream of NIK/IKKα, single lab","pmids":["10764746"],"is_preprint":false},{"year":2001,"finding":"Bioinformatic sequence and structure analysis identified TTRAP (TDP2) as a member of the Mg²⁺/Mn²⁺-dependent phosphodiesterase superfamily related to the human APE1 endonuclease","method":"Sequence alignment and computational structure prediction","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational prediction only, no experimental biochemical validation in this paper","pmids":["11478795"],"is_preprint":false},{"year":2007,"finding":"Ttrap (TDP2) interacts with Alk4 and Smad3 receptors; morpholino knockdown in zebrafish increases Smad3 activity, causing ectopic snail1a expression and apparent repression of e-cadherin, perturbing convergent extension, epiboly and node formation, identifying Ttrap as a negative modulator of Nodal/Smad3 signaling","method":"Co-immunoprecipitation (Alk4/Smad3 interaction), morpholino knockdown in zebrafish, in situ hybridization, RT-PCR for target genes","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus morpholino loss-of-function with defined transcriptional and developmental phenotype, single lab","pmids":["18039968"],"is_preprint":false},{"year":2008,"finding":"TTRAP (TDP2) is a PML nuclear body-associated protein that co-localizes with PML, DAXX, and Sp100; it interacts with these proteins in yeast mating assays and its expression is induced by IFN-γ","method":"Co-localization imaging, yeast mating assay, RT-PCR/Western blot for IFN-γ induction","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, co-localization and yeast interaction assay without functional follow-up","pmids":["18706885"],"is_preprint":false},{"year":2008,"finding":"TTRAP (TDP2) interacts with PD-associated DJ-1 mutants M26I and L166P more strongly than wild-type DJ-1; upon proteasome impairment TTRAP relocalizes to a detergent-insoluble fraction and forms cytoplasmic aggresome-like structures; DJ-1 mutants block TTRAP's protective activity, unmasking JNK- and p38-MAPK-mediated apoptosis","method":"Yeast two-hybrid screen, co-immunoprecipitation, subcellular fractionation, fluorescence imaging, caspase/apoptosis assays","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Y2H + Co-IP interaction, fractionation showing relocalization, functional apoptosis readout, single lab","pmids":["19023331"],"is_preprint":false},{"year":2009,"finding":"TTRAP (TDP2) interacts with HIV-1 integrase via its N-terminal 180 residues; stable TTRAP knockdown decreases lentiviral integration, while TTRAP overexpression increases it, demonstrating a facilitating role in HIV-1 integration","method":"Yeast two-hybrid, co-immunoprecipitation, GST pulldown, intracellular co-localization, stable knockdown and overexpression integration assays","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal binding methods (Y2H, Co-IP, GST-pulldown) plus functional integration assay, single lab","pmids":["19580783"],"is_preprint":false},{"year":2010,"finding":"TDP2/TTRAP is the major (if not the only) 5'-tyrosyl DNA phosphodiesterase activity in vertebrate cells; TDP2-deleted DT40 cells are highly sensitive to etoposide (Top2 poison) but not to camptothecin (Top1 poison) or MMS","method":"Gene deletion in DT40 cells, cell survival assays, biochemical 5'-TDP activity assays in cell extracts","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic KO with specific phenotype, biochemical activity assay, replicated in subsequent work","pmids":["21030584"],"is_preprint":false},{"year":2011,"finding":"TTRAP (TDP2) accumulates in nucleolar cavities upon proteasome inhibition in a PML-dependent manner; within the nucleolus, TTRAP controls levels of ribosomal RNA precursor and processing intermediates through a mechanism independent of its 5'-tyrosyl DNA phosphodiesterase activity","method":"Fluorescence microscopy, RNA analysis, proteasome inhibitor treatment, PML knockdown, TDP2 catalytic mutant complementation","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live-cell imaging with subcellular localization tied to rRNA phenotype, catalytic mutant separates functions, single lab","pmids":["21921940"],"is_preprint":false},{"year":2011,"finding":"TTRAP (TDP2) associates with TGF-β receptors and components of the TRAF6-TAK1 signaling module; modulation of TTRAP levels differentially regulates TGF-β-activated p38 and NF-κB responses, and affects cell viability in the presence of TGF-β","method":"Co-immunoprecipitation, TTRAP knockdown/overexpression, reporter assays, cell viability assays","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus functional reporter and viability assays, single lab","pmids":["21980489"],"is_preprint":false},{"year":2012,"finding":"Crystal structure of zebrafish TDP2 bound to DNA reveals a deep, narrow basic groove that selectively accommodates the 5' end of single-stranded DNA in a stretched conformation; C. elegans TDP2 structure shows this groove can also accommodate an acidic peptide in vitro, suggesting molecular mimicry as a potential autoregulation and signaling mechanism","method":"X-ray crystallography, in vitro binding assays","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures of two orthologs with functional validation of substrate selectivity","pmids":["23104058"],"is_preprint":false},{"year":2012,"finding":"Human TDP2 is a Mg²⁺/Mn²⁺-dependent phosphodiesterase; preferred substrate is single-stranded or 4-bp overhang duplex DNA bearing a 5'-phosphotyrosyl bond; kcat/Km is ~4×10⁵ s⁻¹M⁻¹; catalytic residues Asn-120, Glu-152, Asp-262, and His-351 are essential for activity; a two-metal mechanism is proposed","method":"In vitro enzyme assays with recombinant TDP2, site-directed mutagenesis of active-site residues, metal titration, kinetic parameter determination","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with mutagenesis of multiple catalytic residues and kinetic characterization","pmids":["22822062"],"is_preprint":false},{"year":2012,"finding":"TDP2 promotes repair of Top1-mediated DNA breaks in the absence of TDP1; double deletion of Tdp1 and Tdp2 reduces strand break repair and cell survival below Tdp1-/- alone; TDP2 overexpression in Tdp1-/-/Tdp2-/-/- cells partially rescues the Tdp1-/- defect; Tdp1/Tdp2 double KO mice are more sensitive to Top1 poisons than Tdp1 KO alone","method":"Gene deletion in DT40 cells and mouse embryonic fibroblasts, DNA strand break repair assays, cell survival assays, mouse in vivo sensitivity experiments","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with single, double, and rescue experiments in multiple cell types plus in vivo mouse data","pmids":["22740648"],"is_preprint":false},{"year":2012,"finding":"DJ-1 L166P mutation alters rRNA biogenesis by sequestering TTRAP (TDP2) from the nucleolus into cytoplasmic aggregates via a TRAF6-dependent mechanism; TTRAP is found associated with nucleolus and Lewy bodies in post-mortem sporadic PD brain","method":"Subcellular fractionation, fluorescence imaging, RNA analysis, TRAF6 inhibition, immunohistochemistry of PD brain tissue","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — localization and functional rRNA readout linked to TRAF6, supported by human post-mortem tissue, single lab","pmids":["22532838"],"is_preprint":false},{"year":2013,"finding":"TDP2 functions in NHEJ to liberate 5'-phosphotyrosyl DSB termini competent for ligation; Tdp2-deleted mice are sensitive to TOP2-induced damage with lymphoid toxicity, intestinal damage, and increased bone marrow genome instability","method":"TDP2 KO DT40 cells and mice, NHEJ end-ligation assays, γ-H2AX foci, chromosome instability assays, in vivo etoposide treatment","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO in cells and mice with multiple orthogonal readouts (NHEJ assay, survival, genome instability) demonstrating pathway function","pmids":["23505375"],"is_preprint":false},{"year":2014,"finding":"TDP2 is required for TOP2-dependent gene transcription in human cells and mouse post-mitotic neurons; loss of TDP2 inhibits transcription following abortive TOP2 activity, and TDP2 is required for normal levels of many neuronal gene transcripts and normal interneuron density in mouse cerebellum","method":"Homozygous TDP2 mutations identified in patients; patient cell hypersensitivity assays; TOP2-dependent transcription assays in cultured cells and mouse neurons; gene expression analysis in developing mouse brain; immunohistochemistry for interneuron density","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — human genetics combined with multiple cellular and in vivo functional assays across labs (human patients + mouse model)","pmids":["24658003"],"is_preprint":false},{"year":2014,"finding":"TDP2 requires prior proteolytic processing or denaturation of irreversible Top2 cleavage complexes before it can act; TDP2 is most efficient on single-stranded DNA substrates; TDP2 can remove tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides; crystal structure at 1.6-Å defines how RNA is accommodated in the TDP2 active site in a strained conformation","method":"In vitro TDP2 cleavage assays with suicidal substrates, X-ray crystallography at 1.6 Å of TDP2–RNA substrate complex","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution assays combined with high-resolution crystal structure defining mechanism","pmids":["24808172"],"is_preprint":false},{"year":2014,"finding":"Human and chicken TDP2 (but not human TDP1) can specifically cleave the Tyr-DNA bond in HBV and DHBV RC-DNA substrates and release viral P protein in vitro without prior proteolysis; RNAi-mediated TDP2 depletion in human cells slows conversion of RC-DNA to cccDNA, and ectopic TDP2 expression restores faster conversion, establishing TDP2 as a host factor in HBV cccDNA biogenesis","method":"In vitro cleavage assays with virus-adapted substrates, RNAi knockdown, ectopic expression, Southern blot quantification of cccDNA","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro biochemical assay plus RNAi loss-of-function and rescue experiments in cells","pmids":["25201958"],"is_preprint":false},{"year":2016,"finding":"ERK3 (an atypical MAPK) phosphorylates TDP2 at serine 60 and regulates its 5'-phosphodiesterase activity, thereby cooperatively protecting lung cancer cells against TOP2 inhibitor-induced DNA damage and growth inhibition","method":"In vitro kinase assay, phosphorylation site mapping (S60), phosphodiesterase activity assays, cell survival assays with TOP2 inhibitors","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro kinase assay identifying phosphorylation site plus functional activity and cell survival assays, single lab","pmids":["26701725"],"is_preprint":false},{"year":2016,"finding":"X-ray crystal structures of ligand-free Tdp2 and Tdp2-DNA complexes with alkylated and abasic DNA reveal a dynamic active site lid and deep substrate binding trench; mutagenesis and biochemical studies support a single Mg²⁺-ion mechanism assisted by a phosphotyrosyl-arginine cation-π interface; a Tdp2 active site SNP ablates Mg²⁺ binding and catalytic activity, impairs NHEJ of tyrosine-blocked termini, and renders cells etoposide-sensitive","method":"X-ray crystallography, active-site mutagenesis, biochemical phosphodiesterase assays, NHEJ end-joining assay, cell survival assay","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures combined with mutagenesis, biochemical reconstitution, and cellular functional assays in one study","pmids":["27060144"],"is_preprint":false},{"year":2016,"finding":"TDP2 N-terminal region contains a ubiquitin-associated (UBA) domain that binds multiple ubiquitin forms, preferring K48- or K63-linked polyUbs over monoUb; crystal structure of TDP2 UBA bound to monoUb reveals a canonical UBA-Ub interaction lacking the conserved MGF motif; mutations in the UBA-Ub binding interface do not affect nuclear import of TDP2 but severely compromise repair of Top2-mediated DNA damage","method":"X-ray crystallography of UBA-Ub complex, isothermal titration calorimetry, mutagenesis, nuclear import assays, DNA damage repair assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus mutagenesis with functional repair readout, multiple orthogonal methods","pmids":["27543075"],"is_preprint":false},{"year":2017,"finding":"TDP2 rejoins DSBs induced during transcription-dependent TOP2 activity at the MLL translocation hotspot; TDP2 suppresses TOP2-induced chromosome rearrangements; however, TDP2-dependent NHEJ contributes to a rare subclass of translocations with 4-bp perfect homology junctions associated with therapy-related leukemia","method":"ChIP for TDP2 at TOP2 sites/MLL locus, chromosome translocation assays, NHEJ junction sequencing in TDP2-proficient and -deficient breast cancer cells","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal assays (ChIP, translocation frequency, junction analysis) in defined cell systems","pmids":["28794467"],"is_preprint":false},{"year":2018,"finding":"TDP2 does not remove intact TOP2-DNA complexes from genomic DNA in vitro and TDP2 depletion in cells does not slow removal of TOP2-DNA complexes by itself, indicating that prior processing steps (proteasomal degradation) are required before TDP2 can act on the remaining 5'-tyrosine adduct; SUMOylated TOP2-DNA complex levels and DSB levels are unaffected by TDP2 knockdown in K562 cells after etoposide and proteasome inhibition","method":"In vitro TDP2 cleavage assays on genomic DNA, TARDIS assay for TOP2-DNA complexes in cells, TDP2 knockdown, SUMOylated TOP2 TARDIS assay","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — adapted TARDIS assay plus in vitro assay; negative results are mechanistically informative (prior proteolysis required), single lab","pmids":["30011940"],"is_preprint":false},{"year":2018,"finding":"TDP2 exists as two isoforms: full-length TDP2 with a nuclear localization signal and UBA domain (N-terminus), and a short isoform TDP2S that contains a mitochondrial targeting sequence and localizes to mitochondria and cytosol; both isoforms are active in mitochondria; TDP2 KO cells are hypersensitive to mitochondrial-targeted doxorubicin and show selective mitochondrial DNA depletion; TDP2S alone can protect against mitochondrial doxorubicin; loss of TDP2 reduces mitochondrial transcription levels","method":"Alternative TSS mapping, subcellular fractionation, mitochondrial import assays, TDP2 KO and rescue experiments, cell survival assays, mtDNA quantification, mitochondrial transcription assays, CRISPR engineering","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (fractionation, KO/rescue, CRISPR), identification of novel isoform with functional validation","pmids":["29438979"],"is_preprint":false},{"year":2019,"finding":"C. elegans TDP2 ortholog TDPT-1 induces SUMOylation of the ETS transcription factor ETS-4, inhibiting ETS-4 transcriptional activity and negatively regulating axon regeneration; MXL-1 (Max-like transcription factor) binds and inhibits TDPT-1, counteracting ETS-4 SUMOylation; tdpt-1 deletion suppresses mxl-1 but not ets-4 axon regeneration defects","method":"Genetic epistasis (deletion analysis in C. elegans), co-immunoprecipitation, SUMOylation assays, axon regeneration assays","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis plus biochemical SUMOylation assay, single lab, C. elegans ortholog","pmids":["31393064"],"is_preprint":false},{"year":2020,"finding":"TDP2 co-purifies with K63- and K27-poly-ubiquitinated cellular proteins; poly-ubiquitin chains of ≥Ub3 stimulate TDP2 catalytic activity in nuclear extracts and enhance TDP2 binding of DNA-protein crosslinks in vitro; crystal structures and SAXS of TDP2-Ub complexes show the TDP2 UBA domain binds K63-Ub3 in a 1:1 complex that relieves an autoinhibitory state; TDP2 SNPs can disrupt the TDP2-Ubiquitin interface","method":"Affinity purification/co-purification, in vitro phosphodiesterase stimulation assays with nuclear extracts, X-ray crystallography, small-angle X-ray scattering (SAXS), SNP analysis","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus SAXS plus in vitro functional assays defining allosteric mechanism, multiple orthogonal methods","pmids":["32356875"],"is_preprint":false},{"year":2020,"finding":"TDP2 promotes the second step (peptide removal) of TOP1cc repair in the absence of TDP1; TDP1-/-TDP2-/- cells are more sensitive than TDP1-/- or TDP2-/- cells to agents producing 3'-blocking lesions (AZT, cytarabine, abacavir, gemcitabine, trifluridine), confirming TDP2's role in repairing 3'-blocking lesions","method":"Antibody-based TOP1cc repair kinetics assay, TDP1 and TDP2 single/double KO TK6 cells, cell survival assays","journal":"DNA repair","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — novel kinetics assay with defined genetic system, single lab","pmids":["32460231"],"is_preprint":false},{"year":2020,"finding":"Catalytically inactive TDP2 does not rescue the picornavirus (poliovirus/CVB3) growth defect in TDP2 KO human RPE-1 cells, confirming that TDP2 5'-phosphodiesterase (VPg unlinkase) activity is required for efficient enterovirus replication; VPg removal is required for steps downstream of translation, including negative- and positive-strand RNA synthesis","method":"CRISPR/Cas9 TDP2 KO, catalytic mutant complementation, virus growth kinetics, viral protein and RNA assays, polysome assembly, dsRNA detection","journal":"Viruses","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — catalytic mutant rescue plus multiple viral replication readouts, single lab","pmids":["32023921"],"is_preprint":false},{"year":2020,"finding":"TDP2 suppresses androgen-induced DNA double-strand breaks in human prostate cancer cells during G1 phase; loss of TDP2 causes five times more androgen-induced chromosome breaks in mitotic spreads; TDP2-deficient mice accumulate DSBs in prostate epithelial cells after androgen injection, demonstrating a physiological role for TDP2 in repairing stalled TOP2ccs induced by androgens","method":"γ-H2AX foci, chromosome break assays in mitotic spreads, TDP2 KO cells and mice, in vivo androgen injection","journal":"Genes to cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO in cells and mice with quantitative chromosome break readouts, single lab","pmids":["32277721"],"is_preprint":false},{"year":2023,"finding":"TDP2 repairs TOP1-induced 3'-blocking lesions via a Mg²⁺-dependent catalytic mechanism similar to TOP2-damage repair; Mg²⁺-TDP2 binding is required for repair of both TOP1- and TOP2-induced DNA damage, as well as for repair of incorporated chain-terminating nucleoside analogs at 3' ends","method":"In vitro phosphodiesterase assays with metal chelation, mutagenesis of Mg²⁺ binding residues, cell survival assays in TDP1/TDP2 KO TK6 cells","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with mutagenesis, single lab, mechanism inferred from biochemical data without structural validation","pmids":["37392847"],"is_preprint":false}],"current_model":"TDP2 (TTRAP/EAPII) is a Mg²⁺/Mn²⁺-dependent 5'-tyrosyl-DNA phosphodiesterase that hydrolyzes the phosphotyrosyl bond linking topoisomerase II (and to a lesser extent topoisomerase I) to DSB ends, acting through a single-Mg²⁺ catalytic mechanism assisted by a phosphotyrosyl-arginine cation-π interface; it operates in error-free NHEJ after prior proteolytic processing of the trapped topoisomerase, is stimulated by K63/K27-polyubiquitin binding to its N-terminal UBA domain (relieving autoinhibition), is phosphorylated at S60 by ERK3 to regulate its activity, localizes to the nucleus (full-length isoform) and mitochondria (TDP2S short isoform), is required for TOP2-dependent gene transcription, suppresses TOP2-induced chromosomal translocations, serves as a VPg unlinkase essential for picornavirus RNA replication, participates in HBV cccDNA biogenesis, modulates Nodal/Smad3 and NF-κB/TRAF6 signaling pathways, and its loss causes spinocerebellar ataxia (SCAR23) due to defective neuronal DSB repair."},"narrative":{"mechanistic_narrative":"TDP2 (TTRAP/EAPII) is the major vertebrate 5'-tyrosyl-DNA phosphodiesterase, hydrolyzing the covalent phosphotyrosyl bond that links trapped topoisomerase II to double-strand break ends and thereby enabling error-free repair [PMID:21030584, PMID:22822062]. Originally identified as a TRAF-interacting protein that restrains NF-κB activation upstream of NIK/IKKα and modulates TGF-β/Nodal-Smad3 signaling [PMID:10764746, PMID:18039968, PMID:21980489], TDP2 was subsequently established biochemically as a Mg²⁺/Mn²⁺-dependent phosphodiesterase of the APE1-related superfamily whose activity depends on a defined active-site (Asn120, Glu152, Asp262, His351) operating through a single-Mg²⁺ mechanism assisted by a phosphotyrosyl-arginine cation-π interface, acting preferentially on single-stranded 5'-phosphotyrosyl termini [PMID:22822062, PMID:27060144]. Crystallographic work defined a deep basic substrate trench with a dynamic lid that selectively accommodates stretched 5'-DNA ends and can also bind RNA in a strained conformation [PMID:23104058, PMID:24808172, PMID:27060144]. TDP2 acts within NHEJ to liberate ligatable 5'-phosphotyrosyl DSB termini, but only after the trapped TOP2 is first proteolytically processed, since TDP2 cannot act on intact TOP2-DNA complexes [PMID:23505375, PMID:30011940]. Its catalytic activity is allosterically controlled: K63/K27-polyubiquitin chains bind its N-terminal UBA domain to relieve an autoinhibitory state and stimulate phosphodiesterase activity, and ERK3 phosphorylates TDP2 at Ser60 to regulate activity [PMID:27543075, PMID:32356875, PMID:26701725]. TDP2 is required for TOP2-dependent gene transcription and for normal neuronal gene expression and interneuron density, and biallelic loss-of-function mutations cause spinocerebellar ataxia (SCAR23) [PMID:24658003]. Beyond TOP2, TDP2 contributes to repair of TOP1-mediated and 3'-blocking lesions in the absence of TDP1 [PMID:22740648, PMID:32460231, PMID:37392847], suppresses TOP2-induced and androgen-induced chromosomal breaks and translocations [PMID:28794467, PMID:32277721], functions in mitochondria via a short mitochondrial-targeted isoform (TDP2S) to protect mtDNA [PMID:29438979], and is hijacked by viruses, serving as the VPg unlinkase required for picornavirus replication and as a host factor in HBV cccDNA biogenesis [PMID:32023921, PMID:25201958].","teleology":[{"year":2000,"claim":"Before any catalytic role was known, TDP2 was placed in receptor signaling, answering whether it had a defined cellular function by linking it to TRAF-dependent NF-κB control.","evidence":"Yeast two-hybrid, Co-IP, and reporter assays mapping TRAF binding and NF-κB inhibition upstream of NIK/IKKα","pmids":["10764746"],"confidence":"Medium","gaps":["No biochemical activity assigned","Mechanism of NF-κB inhibition not resolved at the molecular level"]},{"year":2001,"claim":"A bioinformatic prediction first hinted that TDP2 was an enzyme, classifying it within the Mg²⁺/Mn²⁺-dependent phosphodiesterase superfamily related to APE1.","evidence":"Sequence alignment and computational structure prediction","pmids":["11478795"],"confidence":"Low","gaps":["Computational only; no experimental enzymatic validation","No substrate identified"]},{"year":2007,"claim":"Loss-of-function in vivo connected TDP2 to developmental signaling, showing it negatively modulates Nodal/Smad3 signaling.","evidence":"Co-IP of Alk4/Smad3 plus morpholino knockdown with transcriptional and morphogenetic phenotypes in zebrafish","pmids":["18039968"],"confidence":"Medium","gaps":["Direct enzymatic versus scaffolding contribution unresolved","Mammalian relevance not established"]},{"year":2008,"claim":"Interaction screens placed TDP2 in PML nuclear bodies and linked it to Parkinson-associated DJ-1, raising a cytoprotective and stress-response role.","evidence":"Y2H, Co-IP, co-localization with PML/DAXX/Sp100, fractionation, and apoptosis assays","pmids":["18706885","19023331"],"confidence":"Low","gaps":["Single-lab co-localization without functional dissection (PML body study)","Mechanism linking DJ-1 mutants to TDP2 protective activity unclear"]},{"year":2009,"claim":"TDP2 was implicated as a host factor for HIV-1 integration, an early hint of viral exploitation predating mechanistic understanding.","evidence":"Y2H, Co-IP, GST-pulldown with HIV-1 integrase plus knockdown/overexpression integration assays","pmids":["19580783"],"confidence":"Medium","gaps":["Whether catalytic activity is required not tested","Direct versus indirect effect on integration unresolved"]},{"year":2010,"claim":"Genetic deletion established TDP2 as the dominant cellular 5'-tyrosyl-DNA phosphodiesterase and pinned its function to TOP2-poison resistance.","evidence":"DT40 gene deletion with etoposide/camptothecin/MMS survival and biochemical 5'-TDP activity assays","pmids":["21030584"],"confidence":"High","gaps":["Catalytic residues and structural basis not yet defined","Pathway placement within NHEJ not established"]},{"year":2012,"claim":"Reconstitution and crystallography defined the catalytic machinery and substrate selectivity, converting the bioinformatic prediction into a validated enzyme mechanism.","evidence":"Recombinant enzyme kinetics with active-site mutagenesis (Asn120/Glu152/Asp262/His351) plus zebrafish and C. elegans crystal structures bound to DNA/peptide","pmids":["22822062","23104058"],"confidence":"High","gaps":["Metal stoichiometry debated (two-metal vs single-metal)","Regulation in cells not addressed"]},{"year":2012,"claim":"Genetic epistasis revealed a backup role beyond TOP2, showing TDP2 also processes TOP1-mediated breaks when TDP1 is absent.","evidence":"Single/double/rescue deletions in DT40 and MEFs plus in vivo mouse Top1-poison sensitivity","pmids":["22740648"],"confidence":"High","gaps":["Relative physiological contribution to TOP1 repair unclear","Mechanism of 3'-lesion processing not yet biochemically defined"]},{"year":2013,"claim":"Cell and mouse studies placed TDP2 functionally within NHEJ, demonstrating it generates ligatable termini and protects against TOP2-induced genome instability in vivo.","evidence":"TDP2 KO DT40 cells and mice with NHEJ end-ligation, γ-H2AX, chromosome instability, and etoposide challenge","pmids":["23505375"],"confidence":"High","gaps":["Requirement for prior TOP2 processing not yet shown","Identity of upstream proteolytic factors unknown"]},{"year":2014,"claim":"Human genetics defined a disease role and a transcription function, showing TDP2 loss causes ataxia and is required for TOP2-dependent gene transcription in neurons.","evidence":"Homozygous patient mutations, patient-cell hypersensitivity, TOP2-dependent transcription assays, and mouse cerebellar gene-expression/interneuron analysis","pmids":["24658003"],"confidence":"High","gaps":["Molecular link between repair defect and transcriptional loss incomplete","Neuron-specific vulnerability mechanism unclear"]},{"year":2014,"claim":"Structural and biochemical work showed TDP2 acts only after TOP2 processing and broadened its substrate scope to ribonucleotide-linked tyrosyl adducts.","evidence":"In vitro cleavage of suicidal substrates plus 1.6-Å crystal structure of a TDP2-RNA complex","pmids":["24808172"],"confidence":"High","gaps":["Identity of in vivo processing protease not defined","Physiological role of RNA-adduct cleavage unclear"]},{"year":2014,"claim":"TDP2 was identified as a host factor for HBV cccDNA formation, generalizing its tyrosyl-phosphodiesterase activity to viral protein-DNA linkages.","evidence":"In vitro cleavage of HBV/DHBV RC-DNA substrates plus RNAi knockdown and rescue with cccDNA Southern quantification","pmids":["25201958"],"confidence":"High","gaps":["Whether TDP2 acts on RC-DNA in vivo without proteolysis not fully resolved","Contribution relative to other host factors unquantified"]},{"year":2016,"claim":"Discovery of UBA-domain ubiquitin binding and ERK3 phosphorylation revealed how TDP2 activity and recruitment are regulated.","evidence":"Crystal structure of UBA-monoUb, ITC, and mutagenesis with repair readout; separate in vitro kinase mapping of S60 with activity and survival assays","pmids":["27543075","26701725"],"confidence":"High","gaps":["Physiological ubiquitin ligase/source of polyUb not identified","ERK3-TDP2 regulation single-lab (Medium)"]},{"year":2016,"claim":"Higher-resolution structures with damaged DNA refined the catalytic model to a single-Mg²  mechanism with a cation-π interface, and tied a human SNP to enzymatic and repair failure.","evidence":"X-ray structures of ligand-free and DNA-bound TDP2, active-site mutagenesis, NHEJ end-joining, and survival assays","pmids":["27060144"],"confidence":"High","gaps":["Population frequency and clinical impact of catalytic SNPs unaddressed"]},{"year":2017,"claim":"TDP2 was shown to suppress TOP2-induced chromosomal translocations while paradoxically contributing to a rare leukemogenic translocation subclass through its NHEJ activity.","evidence":"ChIP at TOP2/MLL sites, translocation frequency, and junction sequencing in TDP2-proficient/-deficient cells","pmids":["28794467"],"confidence":"High","gaps":["Determinants directing protective versus mutagenic outcomes unclear"]},{"year":2018,"claim":"Identification of the mitochondrial TDP2S isoform extended TDP2's repair role to mtDNA, answering where TDP2 acts outside the nucleus.","evidence":"TSS mapping, fractionation, import assays, KO/rescue, mtDNA quantification, and mitochondrial transcription assays","pmids":["29438979"],"confidence":"High","gaps":["Mitochondrial topoisomerase substrate not directly defined","Regulation of isoform choice unknown"]},{"year":2018,"claim":"A negative-result study established the order of events, demonstrating TDP2 requires prior proteasomal processing of TOP2-DNA complexes before it can act.","evidence":"In vitro cleavage of genomic DNA and TARDIS-based TOP2-DNA complex quantification under TDP2 knockdown and proteasome inhibition","pmids":["30011940"],"confidence":"Medium","gaps":["Identity and regulation of upstream proteases not resolved","Single-lab cellular assay"]},{"year":2019,"claim":"An ortholog study uncovered a non-canonical activity, showing TDP2/TDPT-1 promotes SUMOylation of an ETS transcription factor to restrain axon regeneration.","evidence":"C. elegans genetic epistasis, Co-IP, and SUMOylation assays","pmids":["31393064"],"confidence":"Medium","gaps":["Whether mammalian TDP2 has analogous SUMO-related activity untested","Mechanism by which TDP2 promotes SUMOylation unclear"]},{"year":2020,"claim":"Structural and biochemical work defined an allosteric switch, showing K63-polyubiquitin binding to the UBA domain relieves TDP2 autoinhibition and stimulates catalysis.","evidence":"Co-purification of polyubiquitinated proteins, in vitro stimulation assays, and crystal/SAXS structures of TDP2-Ub3 complexes","pmids":["32356875"],"confidence":"High","gaps":["In vivo trigger and ligase generating the activating chains unidentified"]},{"year":2020,"claim":"Functional studies extended TDP2's repair scope to 3'-blocking lesions and chain-terminating nucleoside analogs, and demonstrated catalytic requirement for picornavirus replication and androgen-damage suppression.","evidence":"TDP1/TDP2 KO TK6 survival and TOP1cc kinetics; catalytic-mutant rescue of poliovirus/CVB3 in RPE-1 KO; KO cell/mouse androgen-induced break assays","pmids":["32460231","32023921","32277721"],"confidence":"Medium","gaps":["Mechanistic basis of 3'-lesion versus 5'-lesion specificity not fully resolved","Each result single-lab"]},{"year":2023,"claim":"Biochemical dissection confirmed a unified Mg²⁺-dependent mechanism for TDP2 across TOP1- and TOP2-induced and 3'-blocking lesions.","evidence":"In vitro phosphodiesterase assays with metal chelation and Mg²⁺-site mutagenesis plus survival in TDP1/TDP2 KO TK6 cells","pmids":["37392847"],"confidence":"Medium","gaps":["No structural validation of 3'-lesion engagement","Single-lab"]},{"year":null,"claim":"The in vivo signals and enzymes that govern TDP2 recruitment and activation remain undefined: the proteases that process trapped TOP2, the ligases generating activating polyubiquitin chains, and how its repair, transcription, signaling, and viral roles are coordinated are unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["Upstream protease for TOP2cc processing unidentified","Physiological ubiquitin source for UBA activation unknown","Integration of catalytic and signaling/scaffolding functions unclear"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140097","term_label":"catalytic activity, acting on DNA","supporting_discovery_ids":[6,10,15,16,18,28]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[10,18,28]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[9,18]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2,8]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[19,22]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[7,12]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[22]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[22]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[6,11,13,18,25,28]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[14,22]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[14,16,26,20]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,8]}],"complexes":[],"partners":["TRAF6","SMAD3","DJ-1 (PARK7)","PML","ERK3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95551","full_name":"Tyrosyl-DNA phosphodiesterase 2","aliases":["5'-tyrosyl-DNA phosphodiesterase","5'-Tyr-DNA phosphodiesterase","ETS1-associated protein 2","ETS1-associated protein II","EAPII","TRAF and TNF receptor-associated protein","Tyrosyl-RNA phosphodiesterase","VPg unlinkase"],"length_aa":362,"mass_kda":40.9,"function":"DNA repair enzyme that can remove a variety of covalent adducts from DNA through hydrolysis of a 5'-phosphodiester bond, giving rise to DNA with a free 5' phosphate. Catalyzes the hydrolysis of dead-end complexes between DNA and the topoisomerase 2 (TOP2) active site tyrosine residue. The 5'-tyrosyl DNA phosphodiesterase activity can enable the repair of TOP2-induced DNA double-strand breaks/DSBs without the need for nuclease activity, creating a 'clean' DSB with 5'-phosphate termini that are ready for ligation (PubMed:27060144, PubMed:27099339). Thereby, protects the transcription of many genes involved in neurological development and maintenance from the abortive activity of TOP2. Hydrolyzes 5'-phosphoglycolates on protruding 5' ends on DSBs due to DNA damage by radiation and free radicals. Has preference for single-stranded DNA or duplex DNA with a 4 base pair overhang as substrate. Acts as a regulator of ribosome biogenesis following stress. Also has 3'-tyrosyl DNA phosphodiesterase activity, but less efficiently and much slower than TDP1. Constitutes the major if not only 5'-tyrosyl-DNA phosphodiesterase in cells. Also acts as an adapter by participating in the specific activation of MAP3K7/TAK1 in response to TGF-beta: associates with components of the TGF-beta receptor-TRAF6-TAK1 signaling module and promotes their ubiquitination dependent complex formation. Involved in non-canonical TGF-beta induced signaling routes. May also act as a negative regulator of ETS1 and may inhibit NF-kappa-B activation (Microbial infection) Used by picornaviruses to remove the small polypeptide, VPg (virus Protein genome-linked, the primer for viral RNA synthesis), from the genomic RNA of the virus. Acts as a 5'-tyrosyl RNA phosphodiesterase and cleaves the covalent VPg-Tyr-RNA bond. This cleavage would play a role in viral replication and occur in viral replication vesicles, but would not act on viral mRNA","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/O95551/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TDP2","classification":"Not Classified","n_dependent_lines":188,"n_total_lines":1208,"dependency_fraction":0.15562913907284767},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TDP2","total_profiled":1310},"omim":[{"mim_id":"616949","title":"SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE 23; SCAR23","url":"https://www.omim.org/entry/616949"},{"mim_id":"615708","title":"ZINC FINGER PROTEIN 451; ZNF451","url":"https://www.omim.org/entry/615708"},{"mim_id":"605764","title":"TYROSYL-DNA PHOSPHODIESTERASE 2; TDP2","url":"https://www.omim.org/entry/605764"},{"mim_id":"126430","title":"TOPOISOMERASE, DNA, II, ALPHA; TOP2A","url":"https://www.omim.org/entry/126430"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Nuclear bodies","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"intestine","ntpm":172.6}],"url":"https://www.proteinatlas.org/search/TDP2"},"hgnc":{"alias_symbol":[],"prev_symbol":["TTRAP"]},"alphafold":{"accession":"O95551","domains":[{"cath_id":"-","chopping":"27-61","consensus_level":"high","plddt":90.2971,"start":27,"end":61},{"cath_id":"3.60.10.10","chopping":"112-360","consensus_level":"high","plddt":96.1547,"start":112,"end":360}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95551","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95551-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95551-F1-predicted_aligned_error_v6.png","plddt_mean":85.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TDP2","jax_strain_url":"https://www.jax.org/strain/search?query=TDP2"},"sequence":{"accession":"O95551","fasta_url":"https://rest.uniprot.org/uniprotkb/O95551.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95551/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95551"}},"corpus_meta":[{"pmid":"24856239","id":"PMC_24856239","title":"Tyrosyl-DNA-phosphodiesterases 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chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29677635","citation_count":12,"is_preprint":false},{"pmid":"37392847","id":"PMC_37392847","title":"Repair of topoisomerase 1-induced DNA damage by tyrosyl-DNA phosphodiesterase 2 (TDP2) is dependent on its magnesium binding.","date":"2023","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/37392847","citation_count":11,"is_preprint":false},{"pmid":"29574079","id":"PMC_29574079","title":"New fluorescence-based high-throughput screening assay for small molecule inhibitors of tyrosyl-DNA phosphodiesterase 2 (TDP2).","date":"2018","source":"European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences","url":"https://pubmed.ncbi.nlm.nih.gov/29574079","citation_count":11,"is_preprint":false},{"pmid":"32651480","id":"PMC_32651480","title":"Characterization of a novel loss-of-function variant in TDP2 in two adult patients with spinocerebellar ataxia autosomal recessive 23 (SCAR23).","date":"2020","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32651480","citation_count":9,"is_preprint":false},{"pmid":"32023921","id":"PMC_32023921","title":"Effects of TDP2/VPg Unlinkase Activity on Picornavirus Infections Downstream of Virus Translation.","date":"2020","source":"Viruses","url":"https://pubmed.ncbi.nlm.nih.gov/32023921","citation_count":8,"is_preprint":false},{"pmid":"34606976","id":"PMC_34606976","title":"A novel non-sense mutation in TDP2 causes spinocerebellar ataxia autosomal recessive 23 accompanied by bilateral upward gaze; report of a case and review of the literature.","date":"2021","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34606976","citation_count":8,"is_preprint":false},{"pmid":"37558815","id":"PMC_37558815","title":"Inactivating TDP2 missense mutation in siblings with congenital abnormalities reminiscent of fanconi anemia.","date":"2023","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/37558815","citation_count":7,"is_preprint":false},{"pmid":"32277721","id":"PMC_32277721","title":"TDP2 suppresses genomic instability induced by androgens in the epithelial cells of prostate glands.","date":"2020","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/32277721","citation_count":7,"is_preprint":false},{"pmid":"31393064","id":"PMC_31393064","title":"TDP2 negatively regulates axon regeneration by inducing SUMOylation of an Ets transcription factor.","date":"2019","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/31393064","citation_count":6,"is_preprint":false},{"pmid":"33776385","id":"PMC_33776385","title":"4-Benzylideneisoquinoline-1,3(2H,4H)-diones as tyrosyl DNA phosphodiesterase 2 (TDP2) inhibitors.","date":"2020","source":"Medicinal chemistry research : an international journal for rapid communications on design and mechanisms of action of biologically active agents","url":"https://pubmed.ncbi.nlm.nih.gov/33776385","citation_count":6,"is_preprint":false},{"pmid":"29353210","id":"PMC_29353210","title":"VPg unlinkase/TDP2 in cardiovirus infected cells: Re-localization and proteolytic cleavage.","date":"2018","source":"Virology","url":"https://pubmed.ncbi.nlm.nih.gov/29353210","citation_count":5,"is_preprint":false},{"pmid":"33839584","id":"PMC_33839584","title":"The synthesis of furoquinolinedione and isoxazoloquinolinedione derivatives as selective Tyrosyl-DNA phosphodiesterase 2 (TDP2) inhibitors.","date":"2021","source":"Bioorganic chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/33839584","citation_count":5,"is_preprint":false},{"pmid":"26172204","id":"PMC_26172204","title":"TTRAP is a critical factor in grouper immune response to virus infection.","date":"2015","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/26172204","citation_count":5,"is_preprint":false},{"pmid":"31091068","id":"PMC_31091068","title":"Deazaflavin Inhibitors of TDP2 with Cellular Activity Can Affect Etoposide Influx and/or Efflux.","date":"2019","source":"ACS chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/31091068","citation_count":5,"is_preprint":false},{"pmid":"37047518","id":"PMC_37047518","title":"Genome-Wide CRISPR Screens Reveal ZATT as a Synthetic Lethal Target of TOP2-Poison Etoposide That Can Act in a TDP2-Independent Pathway.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37047518","citation_count":5,"is_preprint":false},{"pmid":"1344894","id":"PMC_1344894","title":"Immunomodulatory effects of fusarochromanones TDP-1 and TDP-2.","date":"1992","source":"Natural toxins","url":"https://pubmed.ncbi.nlm.nih.gov/1344894","citation_count":5,"is_preprint":false},{"pmid":"19598121","id":"PMC_19598121","title":"Essential validation of gene trap mouse ES cell lines: a test case with the gene Ttrap.","date":"2009","source":"The International journal of developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/19598121","citation_count":4,"is_preprint":false},{"pmid":"18226367","id":"PMC_18226367","title":"[Effect of TTRAP expression on apoptosis induced by hydroquinone in HL-60 cells in vitro.].","date":"2007","source":"Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases","url":"https://pubmed.ncbi.nlm.nih.gov/18226367","citation_count":4,"is_preprint":false},{"pmid":"36282523","id":"PMC_36282523","title":"SPRTN and TDP1/TDP2 Independently Suppress 5-Aza-2'-deoxycytidine-Induced Genomic Instability in Human TK6 Cell Line.","date":"2022","source":"Chemical research in toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/36282523","citation_count":3,"is_preprint":false},{"pmid":"39228401","id":"PMC_39228401","title":"Tyrosyl-DNA phosphodiesterase 2 (Tdp2) repairs DNA-protein crosslinks and protects against double strand breaks in vivo.","date":"2024","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/39228401","citation_count":2,"is_preprint":false},{"pmid":"40155951","id":"PMC_40155951","title":"Role of TDP2 in the repair of DNA damage induced by the radiomimetic drug Bleomycin.","date":"2025","source":"Genes and environment : the official journal of the Japanese Environmental Mutagen Society","url":"https://pubmed.ncbi.nlm.nih.gov/40155951","citation_count":2,"is_preprint":false},{"pmid":"38433132","id":"PMC_38433132","title":"A novel pathogenic variant in TDP2 causes spinocerebellar ataxia autosomal recessive 23 accompanied by pituitary tumor and hyperhidrosis: a case report.","date":"2024","source":"Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology","url":"https://pubmed.ncbi.nlm.nih.gov/38433132","citation_count":2,"is_preprint":false},{"pmid":"40581090","id":"PMC_40581090","title":"Post-Translational Modifications Orchestrate Repair of Trapped Topoisomerase-Induced DNA Breaks via TDP1 and TDP2.","date":"2025","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/40581090","citation_count":1,"is_preprint":false},{"pmid":"30588497","id":"PMC_30588497","title":"Erratum: Confirming TDP2 mutation in spinocerebellar ataxia autosomal recessive 23 (SCAR23).","date":"2018","source":"Neurology. Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30588497","citation_count":1,"is_preprint":false},{"pmid":"41481587","id":"PMC_41481587","title":"TDP2 drives immune evasion and metastatic progression in prostate cancer.","date":"2026","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/41481587","citation_count":0,"is_preprint":false},{"pmid":"39801260","id":"PMC_39801260","title":"Design, synthesis, and evaluation of dehydroabietyl imidazolidine-2,4-diones, 2,4,5-triones, and 2-thioxoimidazolidine-4,5-diones as TDP1 inhibitors and dual TDP1/TDP2 inhibitors.","date":"2025","source":"Archiv der Pharmazie","url":"https://pubmed.ncbi.nlm.nih.gov/39801260","citation_count":0,"is_preprint":false},{"pmid":"41541557","id":"PMC_41541557","title":"The effect of dimeric bisbenzimidazoles on the activity of DNA repair enzymes TDP1, TDP2, PARP1 and PARP2.","date":"2025","source":"Vavilovskii zhurnal genetiki i selektsii","url":"https://pubmed.ncbi.nlm.nih.gov/41541557","citation_count":0,"is_preprint":false},{"pmid":"41457191","id":"PMC_41457191","title":"Spinocerebellar ataxia, autosomal recessive type 23 (SCAR23) with compound TDP2 variants: clinical, molecular, and quantitative follow-up.","date":"2025","source":"Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology","url":"https://pubmed.ncbi.nlm.nih.gov/41457191","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":34141,"output_tokens":7405,"usd":0.106749,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":16815,"output_tokens":6304,"usd":0.120838,"stage2_stop_reason":"end_turn"},"total_usd":0.227587,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"TTRAP (TDP2) associates with CD40 cytoplasmic domain, TNF-R75, CD30, and TNF receptor-associated factors (TRAFs), with highest affinity for TRAF6; it inhibits NF-κB transcriptional activation downstream of CD40, TNF-R75, and PMA, but not downstream of NIK, IKKα, or P65/RelA, placing it upstream of these kinases\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, dose-dependent reporter assay in transfected cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assays (Y2H + Co-IP) plus functional reporter assay placing TDP2 upstream of NIK/IKKα, single lab\",\n      \"pmids\": [\"10764746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Bioinformatic sequence and structure analysis identified TTRAP (TDP2) as a member of the Mg²⁺/Mn²⁺-dependent phosphodiesterase superfamily related to the human APE1 endonuclease\",\n      \"method\": \"Sequence alignment and computational structure prediction\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational prediction only, no experimental biochemical validation in this paper\",\n      \"pmids\": [\"11478795\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Ttrap (TDP2) interacts with Alk4 and Smad3 receptors; morpholino knockdown in zebrafish increases Smad3 activity, causing ectopic snail1a expression and apparent repression of e-cadherin, perturbing convergent extension, epiboly and node formation, identifying Ttrap as a negative modulator of Nodal/Smad3 signaling\",\n      \"method\": \"Co-immunoprecipitation (Alk4/Smad3 interaction), morpholino knockdown in zebrafish, in situ hybridization, RT-PCR for target genes\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus morpholino loss-of-function with defined transcriptional and developmental phenotype, single lab\",\n      \"pmids\": [\"18039968\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"TTRAP (TDP2) is a PML nuclear body-associated protein that co-localizes with PML, DAXX, and Sp100; it interacts with these proteins in yeast mating assays and its expression is induced by IFN-γ\",\n      \"method\": \"Co-localization imaging, yeast mating assay, RT-PCR/Western blot for IFN-γ induction\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, co-localization and yeast interaction assay without functional follow-up\",\n      \"pmids\": [\"18706885\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"TTRAP (TDP2) interacts with PD-associated DJ-1 mutants M26I and L166P more strongly than wild-type DJ-1; upon proteasome impairment TTRAP relocalizes to a detergent-insoluble fraction and forms cytoplasmic aggresome-like structures; DJ-1 mutants block TTRAP's protective activity, unmasking JNK- and p38-MAPK-mediated apoptosis\",\n      \"method\": \"Yeast two-hybrid screen, co-immunoprecipitation, subcellular fractionation, fluorescence imaging, caspase/apoptosis assays\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Y2H + Co-IP interaction, fractionation showing relocalization, functional apoptosis readout, single lab\",\n      \"pmids\": [\"19023331\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"TTRAP (TDP2) interacts with HIV-1 integrase via its N-terminal 180 residues; stable TTRAP knockdown decreases lentiviral integration, while TTRAP overexpression increases it, demonstrating a facilitating role in HIV-1 integration\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, GST pulldown, intracellular co-localization, stable knockdown and overexpression integration assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal binding methods (Y2H, Co-IP, GST-pulldown) plus functional integration assay, single lab\",\n      \"pmids\": [\"19580783\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"TDP2/TTRAP is the major (if not the only) 5'-tyrosyl DNA phosphodiesterase activity in vertebrate cells; TDP2-deleted DT40 cells are highly sensitive to etoposide (Top2 poison) but not to camptothecin (Top1 poison) or MMS\",\n      \"method\": \"Gene deletion in DT40 cells, cell survival assays, biochemical 5'-TDP activity assays in cell extracts\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic KO with specific phenotype, biochemical activity assay, replicated in subsequent work\",\n      \"pmids\": [\"21030584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"TTRAP (TDP2) accumulates in nucleolar cavities upon proteasome inhibition in a PML-dependent manner; within the nucleolus, TTRAP controls levels of ribosomal RNA precursor and processing intermediates through a mechanism independent of its 5'-tyrosyl DNA phosphodiesterase activity\",\n      \"method\": \"Fluorescence microscopy, RNA analysis, proteasome inhibitor treatment, PML knockdown, TDP2 catalytic mutant complementation\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell imaging with subcellular localization tied to rRNA phenotype, catalytic mutant separates functions, single lab\",\n      \"pmids\": [\"21921940\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"TTRAP (TDP2) associates with TGF-β receptors and components of the TRAF6-TAK1 signaling module; modulation of TTRAP levels differentially regulates TGF-β-activated p38 and NF-κB responses, and affects cell viability in the presence of TGF-β\",\n      \"method\": \"Co-immunoprecipitation, TTRAP knockdown/overexpression, reporter assays, cell viability assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus functional reporter and viability assays, single lab\",\n      \"pmids\": [\"21980489\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Crystal structure of zebrafish TDP2 bound to DNA reveals a deep, narrow basic groove that selectively accommodates the 5' end of single-stranded DNA in a stretched conformation; C. elegans TDP2 structure shows this groove can also accommodate an acidic peptide in vitro, suggesting molecular mimicry as a potential autoregulation and signaling mechanism\",\n      \"method\": \"X-ray crystallography, in vitro binding assays\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures of two orthologs with functional validation of substrate selectivity\",\n      \"pmids\": [\"23104058\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Human TDP2 is a Mg²⁺/Mn²⁺-dependent phosphodiesterase; preferred substrate is single-stranded or 4-bp overhang duplex DNA bearing a 5'-phosphotyrosyl bond; kcat/Km is ~4×10⁵ s⁻¹M⁻¹; catalytic residues Asn-120, Glu-152, Asp-262, and His-351 are essential for activity; a two-metal mechanism is proposed\",\n      \"method\": \"In vitro enzyme assays with recombinant TDP2, site-directed mutagenesis of active-site residues, metal titration, kinetic parameter determination\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with mutagenesis of multiple catalytic residues and kinetic characterization\",\n      \"pmids\": [\"22822062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"TDP2 promotes repair of Top1-mediated DNA breaks in the absence of TDP1; double deletion of Tdp1 and Tdp2 reduces strand break repair and cell survival below Tdp1-/- alone; TDP2 overexpression in Tdp1-/-/Tdp2-/-/- cells partially rescues the Tdp1-/- defect; Tdp1/Tdp2 double KO mice are more sensitive to Top1 poisons than Tdp1 KO alone\",\n      \"method\": \"Gene deletion in DT40 cells and mouse embryonic fibroblasts, DNA strand break repair assays, cell survival assays, mouse in vivo sensitivity experiments\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with single, double, and rescue experiments in multiple cell types plus in vivo mouse data\",\n      \"pmids\": [\"22740648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"DJ-1 L166P mutation alters rRNA biogenesis by sequestering TTRAP (TDP2) from the nucleolus into cytoplasmic aggregates via a TRAF6-dependent mechanism; TTRAP is found associated with nucleolus and Lewy bodies in post-mortem sporadic PD brain\",\n      \"method\": \"Subcellular fractionation, fluorescence imaging, RNA analysis, TRAF6 inhibition, immunohistochemistry of PD brain tissue\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — localization and functional rRNA readout linked to TRAF6, supported by human post-mortem tissue, single lab\",\n      \"pmids\": [\"22532838\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"TDP2 functions in NHEJ to liberate 5'-phosphotyrosyl DSB termini competent for ligation; Tdp2-deleted mice are sensitive to TOP2-induced damage with lymphoid toxicity, intestinal damage, and increased bone marrow genome instability\",\n      \"method\": \"TDP2 KO DT40 cells and mice, NHEJ end-ligation assays, γ-H2AX foci, chromosome instability assays, in vivo etoposide treatment\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO in cells and mice with multiple orthogonal readouts (NHEJ assay, survival, genome instability) demonstrating pathway function\",\n      \"pmids\": [\"23505375\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"TDP2 is required for TOP2-dependent gene transcription in human cells and mouse post-mitotic neurons; loss of TDP2 inhibits transcription following abortive TOP2 activity, and TDP2 is required for normal levels of many neuronal gene transcripts and normal interneuron density in mouse cerebellum\",\n      \"method\": \"Homozygous TDP2 mutations identified in patients; patient cell hypersensitivity assays; TOP2-dependent transcription assays in cultured cells and mouse neurons; gene expression analysis in developing mouse brain; immunohistochemistry for interneuron density\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — human genetics combined with multiple cellular and in vivo functional assays across labs (human patients + mouse model)\",\n      \"pmids\": [\"24658003\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"TDP2 requires prior proteolytic processing or denaturation of irreversible Top2 cleavage complexes before it can act; TDP2 is most efficient on single-stranded DNA substrates; TDP2 can remove tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides; crystal structure at 1.6-Å defines how RNA is accommodated in the TDP2 active site in a strained conformation\",\n      \"method\": \"In vitro TDP2 cleavage assays with suicidal substrates, X-ray crystallography at 1.6 Å of TDP2–RNA substrate complex\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution assays combined with high-resolution crystal structure defining mechanism\",\n      \"pmids\": [\"24808172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Human and chicken TDP2 (but not human TDP1) can specifically cleave the Tyr-DNA bond in HBV and DHBV RC-DNA substrates and release viral P protein in vitro without prior proteolysis; RNAi-mediated TDP2 depletion in human cells slows conversion of RC-DNA to cccDNA, and ectopic TDP2 expression restores faster conversion, establishing TDP2 as a host factor in HBV cccDNA biogenesis\",\n      \"method\": \"In vitro cleavage assays with virus-adapted substrates, RNAi knockdown, ectopic expression, Southern blot quantification of cccDNA\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro biochemical assay plus RNAi loss-of-function and rescue experiments in cells\",\n      \"pmids\": [\"25201958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"ERK3 (an atypical MAPK) phosphorylates TDP2 at serine 60 and regulates its 5'-phosphodiesterase activity, thereby cooperatively protecting lung cancer cells against TOP2 inhibitor-induced DNA damage and growth inhibition\",\n      \"method\": \"In vitro kinase assay, phosphorylation site mapping (S60), phosphodiesterase activity assays, cell survival assays with TOP2 inhibitors\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro kinase assay identifying phosphorylation site plus functional activity and cell survival assays, single lab\",\n      \"pmids\": [\"26701725\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"X-ray crystal structures of ligand-free Tdp2 and Tdp2-DNA complexes with alkylated and abasic DNA reveal a dynamic active site lid and deep substrate binding trench; mutagenesis and biochemical studies support a single Mg²⁺-ion mechanism assisted by a phosphotyrosyl-arginine cation-π interface; a Tdp2 active site SNP ablates Mg²⁺ binding and catalytic activity, impairs NHEJ of tyrosine-blocked termini, and renders cells etoposide-sensitive\",\n      \"method\": \"X-ray crystallography, active-site mutagenesis, biochemical phosphodiesterase assays, NHEJ end-joining assay, cell survival assay\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures combined with mutagenesis, biochemical reconstitution, and cellular functional assays in one study\",\n      \"pmids\": [\"27060144\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"TDP2 N-terminal region contains a ubiquitin-associated (UBA) domain that binds multiple ubiquitin forms, preferring K48- or K63-linked polyUbs over monoUb; crystal structure of TDP2 UBA bound to monoUb reveals a canonical UBA-Ub interaction lacking the conserved MGF motif; mutations in the UBA-Ub binding interface do not affect nuclear import of TDP2 but severely compromise repair of Top2-mediated DNA damage\",\n      \"method\": \"X-ray crystallography of UBA-Ub complex, isothermal titration calorimetry, mutagenesis, nuclear import assays, DNA damage repair assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus mutagenesis with functional repair readout, multiple orthogonal methods\",\n      \"pmids\": [\"27543075\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TDP2 rejoins DSBs induced during transcription-dependent TOP2 activity at the MLL translocation hotspot; TDP2 suppresses TOP2-induced chromosome rearrangements; however, TDP2-dependent NHEJ contributes to a rare subclass of translocations with 4-bp perfect homology junctions associated with therapy-related leukemia\",\n      \"method\": \"ChIP for TDP2 at TOP2 sites/MLL locus, chromosome translocation assays, NHEJ junction sequencing in TDP2-proficient and -deficient breast cancer cells\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal assays (ChIP, translocation frequency, junction analysis) in defined cell systems\",\n      \"pmids\": [\"28794467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TDP2 does not remove intact TOP2-DNA complexes from genomic DNA in vitro and TDP2 depletion in cells does not slow removal of TOP2-DNA complexes by itself, indicating that prior processing steps (proteasomal degradation) are required before TDP2 can act on the remaining 5'-tyrosine adduct; SUMOylated TOP2-DNA complex levels and DSB levels are unaffected by TDP2 knockdown in K562 cells after etoposide and proteasome inhibition\",\n      \"method\": \"In vitro TDP2 cleavage assays on genomic DNA, TARDIS assay for TOP2-DNA complexes in cells, TDP2 knockdown, SUMOylated TOP2 TARDIS assay\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — adapted TARDIS assay plus in vitro assay; negative results are mechanistically informative (prior proteolysis required), single lab\",\n      \"pmids\": [\"30011940\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TDP2 exists as two isoforms: full-length TDP2 with a nuclear localization signal and UBA domain (N-terminus), and a short isoform TDP2S that contains a mitochondrial targeting sequence and localizes to mitochondria and cytosol; both isoforms are active in mitochondria; TDP2 KO cells are hypersensitive to mitochondrial-targeted doxorubicin and show selective mitochondrial DNA depletion; TDP2S alone can protect against mitochondrial doxorubicin; loss of TDP2 reduces mitochondrial transcription levels\",\n      \"method\": \"Alternative TSS mapping, subcellular fractionation, mitochondrial import assays, TDP2 KO and rescue experiments, cell survival assays, mtDNA quantification, mitochondrial transcription assays, CRISPR engineering\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (fractionation, KO/rescue, CRISPR), identification of novel isoform with functional validation\",\n      \"pmids\": [\"29438979\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"C. elegans TDP2 ortholog TDPT-1 induces SUMOylation of the ETS transcription factor ETS-4, inhibiting ETS-4 transcriptional activity and negatively regulating axon regeneration; MXL-1 (Max-like transcription factor) binds and inhibits TDPT-1, counteracting ETS-4 SUMOylation; tdpt-1 deletion suppresses mxl-1 but not ets-4 axon regeneration defects\",\n      \"method\": \"Genetic epistasis (deletion analysis in C. elegans), co-immunoprecipitation, SUMOylation assays, axon regeneration assays\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis plus biochemical SUMOylation assay, single lab, C. elegans ortholog\",\n      \"pmids\": [\"31393064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TDP2 co-purifies with K63- and K27-poly-ubiquitinated cellular proteins; poly-ubiquitin chains of ≥Ub3 stimulate TDP2 catalytic activity in nuclear extracts and enhance TDP2 binding of DNA-protein crosslinks in vitro; crystal structures and SAXS of TDP2-Ub complexes show the TDP2 UBA domain binds K63-Ub3 in a 1:1 complex that relieves an autoinhibitory state; TDP2 SNPs can disrupt the TDP2-Ubiquitin interface\",\n      \"method\": \"Affinity purification/co-purification, in vitro phosphodiesterase stimulation assays with nuclear extracts, X-ray crystallography, small-angle X-ray scattering (SAXS), SNP analysis\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus SAXS plus in vitro functional assays defining allosteric mechanism, multiple orthogonal methods\",\n      \"pmids\": [\"32356875\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TDP2 promotes the second step (peptide removal) of TOP1cc repair in the absence of TDP1; TDP1-/-TDP2-/- cells are more sensitive than TDP1-/- or TDP2-/- cells to agents producing 3'-blocking lesions (AZT, cytarabine, abacavir, gemcitabine, trifluridine), confirming TDP2's role in repairing 3'-blocking lesions\",\n      \"method\": \"Antibody-based TOP1cc repair kinetics assay, TDP1 and TDP2 single/double KO TK6 cells, cell survival assays\",\n      \"journal\": \"DNA repair\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — novel kinetics assay with defined genetic system, single lab\",\n      \"pmids\": [\"32460231\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Catalytically inactive TDP2 does not rescue the picornavirus (poliovirus/CVB3) growth defect in TDP2 KO human RPE-1 cells, confirming that TDP2 5'-phosphodiesterase (VPg unlinkase) activity is required for efficient enterovirus replication; VPg removal is required for steps downstream of translation, including negative- and positive-strand RNA synthesis\",\n      \"method\": \"CRISPR/Cas9 TDP2 KO, catalytic mutant complementation, virus growth kinetics, viral protein and RNA assays, polysome assembly, dsRNA detection\",\n      \"journal\": \"Viruses\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — catalytic mutant rescue plus multiple viral replication readouts, single lab\",\n      \"pmids\": [\"32023921\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TDP2 suppresses androgen-induced DNA double-strand breaks in human prostate cancer cells during G1 phase; loss of TDP2 causes five times more androgen-induced chromosome breaks in mitotic spreads; TDP2-deficient mice accumulate DSBs in prostate epithelial cells after androgen injection, demonstrating a physiological role for TDP2 in repairing stalled TOP2ccs induced by androgens\",\n      \"method\": \"γ-H2AX foci, chromosome break assays in mitotic spreads, TDP2 KO cells and mice, in vivo androgen injection\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO in cells and mice with quantitative chromosome break readouts, single lab\",\n      \"pmids\": [\"32277721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"TDP2 repairs TOP1-induced 3'-blocking lesions via a Mg²⁺-dependent catalytic mechanism similar to TOP2-damage repair; Mg²⁺-TDP2 binding is required for repair of both TOP1- and TOP2-induced DNA damage, as well as for repair of incorporated chain-terminating nucleoside analogs at 3' ends\",\n      \"method\": \"In vitro phosphodiesterase assays with metal chelation, mutagenesis of Mg²⁺ binding residues, cell survival assays in TDP1/TDP2 KO TK6 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with mutagenesis, single lab, mechanism inferred from biochemical data without structural validation\",\n      \"pmids\": [\"37392847\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TDP2 (TTRAP/EAPII) is a Mg²⁺/Mn²⁺-dependent 5'-tyrosyl-DNA phosphodiesterase that hydrolyzes the phosphotyrosyl bond linking topoisomerase II (and to a lesser extent topoisomerase I) to DSB ends, acting through a single-Mg²⁺ catalytic mechanism assisted by a phosphotyrosyl-arginine cation-π interface; it operates in error-free NHEJ after prior proteolytic processing of the trapped topoisomerase, is stimulated by K63/K27-polyubiquitin binding to its N-terminal UBA domain (relieving autoinhibition), is phosphorylated at S60 by ERK3 to regulate its activity, localizes to the nucleus (full-length isoform) and mitochondria (TDP2S short isoform), is required for TOP2-dependent gene transcription, suppresses TOP2-induced chromosomal translocations, serves as a VPg unlinkase essential for picornavirus RNA replication, participates in HBV cccDNA biogenesis, modulates Nodal/Smad3 and NF-κB/TRAF6 signaling pathways, and its loss causes spinocerebellar ataxia (SCAR23) due to defective neuronal DSB repair.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TDP2 (TTRAP/EAPII) is the major vertebrate 5'-tyrosyl-DNA phosphodiesterase, hydrolyzing the covalent phosphotyrosyl bond that links trapped topoisomerase II to double-strand break ends and thereby enabling error-free repair [#6, #10]. Originally identified as a TRAF-interacting protein that restrains NF-\\u03baB activation upstream of NIK/IKK\\u03b1 and modulates TGF-\\u03b2/Nodal-Smad3 signaling [#0, #2, #8], TDP2 was subsequently established biochemically as a Mg\\u00b2\\u207a/Mn\\u00b2\\u207a-dependent phosphodiesterase of the APE1-related superfamily whose activity depends on a defined active-site (Asn120, Glu152, Asp262, His351) operating through a single-Mg\\u00b2\\u207a mechanism assisted by a phosphotyrosyl-arginine cation-\\u03c0 interface, acting preferentially on single-stranded 5'-phosphotyrosyl termini [#10, #18]. Crystallographic work defined a deep basic substrate trench with a dynamic lid that selectively accommodates stretched 5'-DNA ends and can also bind RNA in a strained conformation [#9, #15, #18]. TDP2 acts within NHEJ to liberate ligatable 5'-phosphotyrosyl DSB termini, but only after the trapped TOP2 is first proteolytically processed, since TDP2 cannot act on intact TOP2-DNA complexes [#13, #21]. Its catalytic activity is allosterically controlled: K63/K27-polyubiquitin chains bind its N-terminal UBA domain to relieve an autoinhibitory state and stimulate phosphodiesterase activity, and ERK3 phosphorylates TDP2 at Ser60 to regulate activity [#19, #24, #17]. TDP2 is required for TOP2-dependent gene transcription and for normal neuronal gene expression and interneuron density, and biallelic loss-of-function mutations cause spinocerebellar ataxia (SCAR23) [#14]. Beyond TOP2, TDP2 contributes to repair of TOP1-mediated and 3'-blocking lesions in the absence of TDP1 [#11, #25, #28], suppresses TOP2-induced and androgen-induced chromosomal breaks and translocations [#20, #27], functions in mitochondria via a short mitochondrial-targeted isoform (TDP2S) to protect mtDNA [#22], and is hijacked by viruses, serving as the VPg unlinkase required for picornavirus replication and as a host factor in HBV cccDNA biogenesis [#26, #16].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Before any catalytic role was known, TDP2 was placed in receptor signaling, answering whether it had a defined cellular function by linking it to TRAF-dependent NF-\\u03baB control.\",\n      \"evidence\": \"Yeast two-hybrid, Co-IP, and reporter assays mapping TRAF binding and NF-\\u03baB inhibition upstream of NIK/IKK\\u03b1\",\n      \"pmids\": [\"10764746\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No biochemical activity assigned\", \"Mechanism of NF-\\u03baB inhibition not resolved at the molecular level\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"A bioinformatic prediction first hinted that TDP2 was an enzyme, classifying it within the Mg\\u00b2\\u207a/Mn\\u00b2\\u207a-dependent phosphodiesterase superfamily related to APE1.\",\n      \"evidence\": \"Sequence alignment and computational structure prediction\",\n      \"pmids\": [\"11478795\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Computational only; no experimental enzymatic validation\", \"No substrate identified\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Loss-of-function in vivo connected TDP2 to developmental signaling, showing it negatively modulates Nodal/Smad3 signaling.\",\n      \"evidence\": \"Co-IP of Alk4/Smad3 plus morpholino knockdown with transcriptional and morphogenetic phenotypes in zebrafish\",\n      \"pmids\": [\"18039968\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct enzymatic versus scaffolding contribution unresolved\", \"Mammalian relevance not established\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Interaction screens placed TDP2 in PML nuclear bodies and linked it to Parkinson-associated DJ-1, raising a cytoprotective and stress-response role.\",\n      \"evidence\": \"Y2H, Co-IP, co-localization with PML/DAXX/Sp100, fractionation, and apoptosis assays\",\n      \"pmids\": [\"18706885\", \"19023331\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single-lab co-localization without functional dissection (PML body study)\", \"Mechanism linking DJ-1 mutants to TDP2 protective activity unclear\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"TDP2 was implicated as a host factor for HIV-1 integration, an early hint of viral exploitation predating mechanistic understanding.\",\n      \"evidence\": \"Y2H, Co-IP, GST-pulldown with HIV-1 integrase plus knockdown/overexpression integration assays\",\n      \"pmids\": [\"19580783\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether catalytic activity is required not tested\", \"Direct versus indirect effect on integration unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Genetic deletion established TDP2 as the dominant cellular 5'-tyrosyl-DNA phosphodiesterase and pinned its function to TOP2-poison resistance.\",\n      \"evidence\": \"DT40 gene deletion with etoposide/camptothecin/MMS survival and biochemical 5'-TDP activity assays\",\n      \"pmids\": [\"21030584\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Catalytic residues and structural basis not yet defined\", \"Pathway placement within NHEJ not established\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Reconstitution and crystallography defined the catalytic machinery and substrate selectivity, converting the bioinformatic prediction into a validated enzyme mechanism.\",\n      \"evidence\": \"Recombinant enzyme kinetics with active-site mutagenesis (Asn120/Glu152/Asp262/His351) plus zebrafish and C. elegans crystal structures bound to DNA/peptide\",\n      \"pmids\": [\"22822062\", \"23104058\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Metal stoichiometry debated (two-metal vs single-metal)\", \"Regulation in cells not addressed\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Genetic epistasis revealed a backup role beyond TOP2, showing TDP2 also processes TOP1-mediated breaks when TDP1 is absent.\",\n      \"evidence\": \"Single/double/rescue deletions in DT40 and MEFs plus in vivo mouse Top1-poison sensitivity\",\n      \"pmids\": [\"22740648\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative physiological contribution to TOP1 repair unclear\", \"Mechanism of 3'-lesion processing not yet biochemically defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Cell and mouse studies placed TDP2 functionally within NHEJ, demonstrating it generates ligatable termini and protects against TOP2-induced genome instability in vivo.\",\n      \"evidence\": \"TDP2 KO DT40 cells and mice with NHEJ end-ligation, \\u03b3-H2AX, chromosome instability, and etoposide challenge\",\n      \"pmids\": [\"23505375\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Requirement for prior TOP2 processing not yet shown\", \"Identity of upstream proteolytic factors unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Human genetics defined a disease role and a transcription function, showing TDP2 loss causes ataxia and is required for TOP2-dependent gene transcription in neurons.\",\n      \"evidence\": \"Homozygous patient mutations, patient-cell hypersensitivity, TOP2-dependent transcription assays, and mouse cerebellar gene-expression/interneuron analysis\",\n      \"pmids\": [\"24658003\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular link between repair defect and transcriptional loss incomplete\", \"Neuron-specific vulnerability mechanism unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Structural and biochemical work showed TDP2 acts only after TOP2 processing and broadened its substrate scope to ribonucleotide-linked tyrosyl adducts.\",\n      \"evidence\": \"In vitro cleavage of suicidal substrates plus 1.6-\\u00c5 crystal structure of a TDP2-RNA complex\",\n      \"pmids\": [\"24808172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of in vivo processing protease not defined\", \"Physiological role of RNA-adduct cleavage unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"TDP2 was identified as a host factor for HBV cccDNA formation, generalizing its tyrosyl-phosphodiesterase activity to viral protein-DNA linkages.\",\n      \"evidence\": \"In vitro cleavage of HBV/DHBV RC-DNA substrates plus RNAi knockdown and rescue with cccDNA Southern quantification\",\n      \"pmids\": [\"25201958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether TDP2 acts on RC-DNA in vivo without proteolysis not fully resolved\", \"Contribution relative to other host factors unquantified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Discovery of UBA-domain ubiquitin binding and ERK3 phosphorylation revealed how TDP2 activity and recruitment are regulated.\",\n      \"evidence\": \"Crystal structure of UBA-monoUb, ITC, and mutagenesis with repair readout; separate in vitro kinase mapping of S60 with activity and survival assays\",\n      \"pmids\": [\"27543075\", \"26701725\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological ubiquitin ligase/source of polyUb not identified\", \"ERK3-TDP2 regulation single-lab (Medium)\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Higher-resolution structures with damaged DNA refined the catalytic model to a single-Mg\\u00b2\\u202f mechanism with a cation-\\u03c0 interface, and tied a human SNP to enzymatic and repair failure.\",\n      \"evidence\": \"X-ray structures of ligand-free and DNA-bound TDP2, active-site mutagenesis, NHEJ end-joining, and survival assays\",\n      \"pmids\": [\"27060144\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Population frequency and clinical impact of catalytic SNPs unaddressed\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"TDP2 was shown to suppress TOP2-induced chromosomal translocations while paradoxically contributing to a rare leukemogenic translocation subclass through its NHEJ activity.\",\n      \"evidence\": \"ChIP at TOP2/MLL sites, translocation frequency, and junction sequencing in TDP2-proficient/-deficient cells\",\n      \"pmids\": [\"28794467\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Determinants directing protective versus mutagenic outcomes unclear\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identification of the mitochondrial TDP2S isoform extended TDP2's repair role to mtDNA, answering where TDP2 acts outside the nucleus.\",\n      \"evidence\": \"TSS mapping, fractionation, import assays, KO/rescue, mtDNA quantification, and mitochondrial transcription assays\",\n      \"pmids\": [\"29438979\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mitochondrial topoisomerase substrate not directly defined\", \"Regulation of isoform choice unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"A negative-result study established the order of events, demonstrating TDP2 requires prior proteasomal processing of TOP2-DNA complexes before it can act.\",\n      \"evidence\": \"In vitro cleavage of genomic DNA and TARDIS-based TOP2-DNA complex quantification under TDP2 knockdown and proteasome inhibition\",\n      \"pmids\": [\"30011940\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity and regulation of upstream proteases not resolved\", \"Single-lab cellular assay\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"An ortholog study uncovered a non-canonical activity, showing TDP2/TDPT-1 promotes SUMOylation of an ETS transcription factor to restrain axon regeneration.\",\n      \"evidence\": \"C. elegans genetic epistasis, Co-IP, and SUMOylation assays\",\n      \"pmids\": [\"31393064\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether mammalian TDP2 has analogous SUMO-related activity untested\", \"Mechanism by which TDP2 promotes SUMOylation unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Structural and biochemical work defined an allosteric switch, showing K63-polyubiquitin binding to the UBA domain relieves TDP2 autoinhibition and stimulates catalysis.\",\n      \"evidence\": \"Co-purification of polyubiquitinated proteins, in vitro stimulation assays, and crystal/SAXS structures of TDP2-Ub3 complexes\",\n      \"pmids\": [\"32356875\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo trigger and ligase generating the activating chains unidentified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Functional studies extended TDP2's repair scope to 3'-blocking lesions and chain-terminating nucleoside analogs, and demonstrated catalytic requirement for picornavirus replication and androgen-damage suppression.\",\n      \"evidence\": \"TDP1/TDP2 KO TK6 survival and TOP1cc kinetics; catalytic-mutant rescue of poliovirus/CVB3 in RPE-1 KO; KO cell/mouse androgen-induced break assays\",\n      \"pmids\": [\"32460231\", \"32023921\", \"32277721\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic basis of 3'-lesion versus 5'-lesion specificity not fully resolved\", \"Each result single-lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Biochemical dissection confirmed a unified Mg\\u00b2\\u207a-dependent mechanism for TDP2 across TOP1- and TOP2-induced and 3'-blocking lesions.\",\n      \"evidence\": \"In vitro phosphodiesterase assays with metal chelation and Mg\\u00b2\\u207a-site mutagenesis plus survival in TDP1/TDP2 KO TK6 cells\",\n      \"pmids\": [\"37392847\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural validation of 3'-lesion engagement\", \"Single-lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The in vivo signals and enzymes that govern TDP2 recruitment and activation remain undefined: the proteases that process trapped TOP2, the ligases generating activating polyubiquitin chains, and how its repair, transcription, signaling, and viral roles are coordinated are unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Upstream protease for TOP2cc processing unidentified\", \"Physiological ubiquitin source for UBA activation unknown\", \"Integration of catalytic and signaling/scaffolding functions unclear\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140097\", \"supporting_discovery_ids\": [6, 10, 15, 16, 18, 28]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [10, 18, 28]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [9, 18]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [19, 22]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [7, 12]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [22]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [22]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [6, 11, 13, 18, 25, 28]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [14, 22]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [14, 16, 26, 20]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TRAF6\", \"SMAD3\", \"DJ-1 (PARK7)\", \"PML\", \"ERK3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}