Affinage

TDRD3

Tudor domain-containing protein 3 · UniProt Q9H7E2

Length
651 aa
Mass
73.2 kDa
Annotated
2026-06-10
18 papers in source corpus 15 papers cited in narrative 15 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TDRD3 is a multifunctional scaffold protein whose Tudor domain reads asymmetric dimethylarginine (aDMA) marks to couple methylarginine signaling to transcriptional regulation, genome stability, and cytoplasmic stress responses (PMID:21172665, PMID:22363433). Its Tudor domain selectively recognizes aDMA marks on histones (H3R17me2a, H4R3me2a) and the RNA Polymerase II CTD, a specificity conferred by a unique aromatic cavity that distinguishes it from sDMA-binding Tudor proteins, and it acts as a transcriptional coactivator recruited to gene start sites in a CARM1-dependent manner (PMID:21172665, PMID:23066109). At promoters, TDRD3 nucleates an R-loop-resolving complex, recruiting the helicase DHX9 through its Tudor domain and the topoisomerase TOP3B through its OB-fold; TDRD3 stimulates DHX9 helicase activity and the two enzymes together suppress promoter-associated R-loops (PMID:28176834, PMID:34329467). TDRD3 also governs TOP3B abundance by recruiting the deubiquitinase USP9X to form a TDRD3-USP9X complex that stabilizes TOP3B and limits accumulation of toxic TOP3B cleavage complexes; loss of TDRD3 induces R-loops, γH2AX, and growth defects (PMID:28101374, PMID:37980342). In the cytoplasm, TDRD3 co-sediments with FMRP on polyribosomes and assembles into stress granules through Tudor-domain-dependent, methylation-sensitive recognition of RGG-methylated RNA-binding proteins, a process promoted by PRMT1 (PMID:18632687, PMID:18664458, PMID:39097054). The TOP3B-TDRD3 complex post-transcriptionally supports neurodevelopmental gene expression and is required for normal cognition and synaptic plasticity in mice (PMID:38216113), and TDRD3 is additionally required for FOXO1-driven Klf2 activation during inducible Treg differentiation (PMID:41576154) and functions as an antiviral restriction factor facilitating interferon signaling (PMID:35085371).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 2008 High

    Established that TDRD3 is a cytoplasmic RNA-regulatory protein, linking it physically to the FMRP family and to stress granule biology before its nuclear role was known.

    Evidence Polyribosome sedimentation, GST pull-down, and Tudor-domain mutagenesis showing co-sedimentation with FMRP, direct binding to FMRP/FXR1/FXR2, and Tudor-dependent stress granule recruitment

    PMID:18632687 PMID:18664458

    Open questions at the time
    • Did not define the methylated ligand recognized by the Tudor domain in stress granules
    • Functional consequence of FMRP-TDRD3 association on translation not resolved
    • OB-fold and UBA domain functions only described biochemically
  2. 2010 High

    Defined TDRD3 as a transcriptional coactivator that reads aDMA histone marks, establishing its nuclear chromatin function and Tudor-domain dependence.

    Evidence Protein domain microarray, ChIP-seq, Tudor mutagenesis, and estrogen-responsive element reporter assays in cells

    PMID:21172665

    Open questions at the time
    • Structural basis of aDMA selectivity not yet resolved
    • Coactivator partners recruited downstream of TDRD3 not identified
  3. 2012 High

    Resolved the structural basis for TDRD3's aDMA preference, explaining how it distinguishes asymmetric from symmetric dimethylarginine and binds the RNA Pol II CTD.

    Evidence Crystal structures with quantitative binding (FP, ITC) and an NMR structure of the Tudor domain bound to aDMA Pol II CTD, with Y566 identified as a selectivity filter

    PMID:22363433 PMID:23066109

    Open questions at the time
    • In vivo consequences of CTD reading on transcription elongation not addressed
    • Did not connect reader activity to a specific downstream effector complex
  4. 2017 Medium

    Connected TDRD3 to two distinct partners that explain its dual roles in protein stability and genome maintenance: USP9X-mediated stabilization and OB-fold-mediated TOP3B binding.

    Evidence GST pull-down, reciprocal Co-IP, ubiquitination assays in USP9X-knockdown and Tdrd3-null MEFs, plus multi-resolution crystal structures of the TDRD3 OB-fold-TOP3B complex with mutagenesis

    PMID:28101374 PMID:28176834

    Open questions at the time
    • Functional integration of USP9X stabilization with TOP3B recruitment not yet unified
    • TOP3B catalytic output downstream of TDRD3 binding not measured in these studies
  5. 2021 High

    Showed that TDRD3 acts as a promoter scaffold coordinating R-loop resolution by recruiting and stimulating DHX9 alongside TOP3B.

    Evidence Co-IP, ChIP, DRIP R-loop detection, helicase activity assays, and a DHX9 helicase-dead rescue with TDRD3 domain deletions

    PMID:34329467

    Open questions at the time
    • Order of recruitment of DHX9 versus TOP3B at promoters not defined
    • Genome-wide rules selecting which promoters require TDRD3 unknown
  6. 2022 Medium

    Extended TDRD3 stress-granule biology to innate immunity, identifying it as an antiviral restriction factor that shapes interferon-effector transcription and is targeted by viral proteases.

    Evidence Immunofluorescence, knockdown/knockout, viral infection assays, and transcriptional profiling showing IRF3/IRF7/TBK1/STING recruitment to stress granules

    PMID:35085371

    Open questions at the time
    • Direct molecular link between TDRD3 granule scaffolding and IFN signaling not established
    • Whether antiviral function requires Tudor-domain methyl reading not tested
  7. 2023 High

    Defined the ubiquitin-regulatory circuit controlling TOP3B levels and the pathological consequences of TDRD3 loss, placing the TDRD3-USP9X complex downstream of the MIB1 E3 ligase.

    Evidence Co-IP, ubiquitylation assays, TOP3Bcc measurement, γH2AX assays, double-knockdown epistasis, and DRIP-seq

    PMID:37980342

    Open questions at the time
    • What activates MIB1-mediated TOP3B degradation is unknown
    • Whether TOP3Bcc accumulation drives the genome-instability phenotype causally not fully separated
  8. 2024 Medium

    Established physiological roles for the TOP3B-TDRD3 complex in brain function and for PRMT1-driven methylation in promoting stress granule assembly.

    Evidence Tdrd3-null mice with behavioral, electrophysiological, neurogenesis, and nascent-versus-mature RNA-seq assays; plus methylation and stress-granule assembly assays dissecting PRMT1-aDMA-reader logic

    PMID:38216113 PMID:39097054

    Open questions at the time
    • Mechanism by which mature but not nascent transcripts are reduced not pinpointed
    • Which RBP substrates of PRMT1 are read by TDRD3 in vivo not enumerated
  9. 2024 Low

    Implicated TDRD3 in selective autophagy via p62-like UBA and LIR motifs that also tune stress-granule dynamics.

    Evidence TDRD3 KO/rescue autophagy flux assays, LIR3-LC3B Co-IP, super-resolution microscopy, and deletion mutants (preprint)

    PMID:39345463

    Open questions at the time
    • Preprint, not yet peer-reviewed; LC3B interaction based on single Co-IP and deletion mutants
    • Cargo selected by TDRD3 as an autophagy receptor not identified
  10. 2026 Medium

    Identified a transcription-factor-directed role for TDRD3 in immune cell differentiation, recruited by FOXO1 to activate Klf2 during iTreg development.

    Evidence Treg-specific conditional Tdrd3-knockout mice, adoptive transfer colitis model, ChIP/transcriptional analysis, and Klf2 enforced-expression rescue

    PMID:41576154

    Open questions at the time
    • Methylation dependence of FOXO1-TDRD3 recruitment assumed but not directly shown
    • Whether this uses the same aDMA-reading mechanism as histone/CTD reading untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How TDRD3's distinct activities — nuclear aDMA reading/R-loop resolution, TOP3B stabilization, cytoplasmic stress-granule and autophagy functions, and antiviral/immune roles — are partitioned and regulated within a cell remains unresolved.
  • No unified model of how methylation signals route TDRD3 between nuclear and cytoplasmic functions
  • Signals controlling switching between coactivator, R-loop, and granule roles unknown
  • No human disease link established by direct genetic evidence in the timeline

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0042393 histone binding 3 GO:0060090 molecular adaptor activity 3 GO:0098772 molecular function regulator activity 3 GO:0003723 RNA binding 2 GO:0140110 transcription regulator activity 2
Localization
GO:0005829 cytosol 3 GO:0005634 nucleus 2
Pathway
R-HSA-168256 Immune System 2 R-HSA-392499 Metabolism of proteins 2 R-HSA-73894 DNA Repair 2 R-HSA-74160 Gene expression (Transcription) 2 R-HSA-8953854 Metabolism of RNA 2
Complex memberships
TDRD3-TOP3B complexTDRD3-USP9X complexstress granule

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2010 TDRD3 Tudor domain functions as a 'reader' of asymmetric dimethylarginine (aDMA) marks on histones (H3R17me2a deposited by CARM1 and H4R3me2a deposited by PRMT1), identified by protein domain microarray. TDRD3 itself acts as a transcriptional coactivator, and this coactivator activity requires an intact Tudor domain. TDRD3 is recruited to an estrogen-responsive element in a CARM1-dependent manner, and ChIP-seq shows it localizes predominantly to transcriptional start sites. Protein domain microarray, co-immunoprecipitation, ChIP-seq, Tudor domain mutagenesis, estrogen-responsive element reporter assay Molecular cell High 21172665
2008 TDRD3 co-sediments with FMRP on actively translating polyribosomes and accumulates in cytoplasmic stress granules (SGs) in response to cellular stress. The Tudor domain is both required and sufficient for SG recruitment, and the methyl-binding surface of the Tudor domain is important for this process. Pull-down experiments identified five novel TDRD3-interacting partners, including SERPINE1 mRNA-binding protein 1 and DDX3 (DEAD/H box-3), which are also novel SG constituents. Polyribosome sedimentation, immunofluorescence, stress induction assays, Tudor domain deletion/mutation analysis, GST pull-down Human molecular genetics High 18632687
2008 TDRD3 harbors an OB-fold domain and a ubiquitin-associated (UBA) domain capable of binding tetra-ubiquitin. TDRD3 directly interacts with FMRP and its autosomal homologs FXR1 and FXR2 via biochemical experiments. Overexpression of TDRD3 in cells induces SG formation and co-localization with endogenous FMRP. The disease-associated FMRP missense mutation I304N severely impairs interaction with TDRD3. Biochemical pull-down/co-immunoprecipitation, domain characterization, overexpression/immunofluorescence, UBA-tetra-ubiquitin binding assay Human molecular genetics Medium 18664458
2012 Crystal structures of the TDRD3 Tudor domain in complex with small molecules reveal that TDRD3 preferentially recognizes asymmetric dimethylarginine (aDMA) marks, in contrast to SMN which preferentially binds symmetric dimethylarginine. Quantitative binding characterization established distinct specificity profiles: TDRD3 selectively binds aDMA; SMN is promiscuous and prefers sDMA; SPF30 is the weakest binder, recognizing only GAR motif sequences. Crystal structure determination, quantitative binding assays (fluorescence polarization, ITC), peptide library screening PloS one High 22363433
2012 NMR solution structure of the TDRD3 Tudor domain bound to asymmetrically dimethylated RNA Polymerase II CTD reveals that a unique aromatic cavity with tyrosine at position 566 acts as a selectivity filter for aDMA recognition, distinguishing it from other Tudor domain-containing proteins that bind symmetric dimethylarginine. Mutational analysis confirmed key residues required for aDMA selectivity. NMR structure determination, mutagenesis, binding assays Nucleic acids research High 23066109
2017 USP9X is identified as a TDRD3-interacting protein; the interaction is mediated through the Tudor domain of TDRD3 and arginine methylation of USP9X. USP9X stabilizes TDRD3 protein by preventing its ubiquitination (knockdown of USP9X increases TDRD3 ubiquitination). TDRD3 is essential for USP9X localization to stress granules. TDRD3 also regulates MCL1 (a USP9X deubiquitination target), suggesting TDRD3 modulates USP9X deubiquitinase activity. GST pull-down, co-immunoprecipitation, USP9X knockdown with ubiquitination assay, immunofluorescence in Tdrd3-null MEFs Cell discovery Medium 28101374
2017 Crystal structures of TOP3B catalytic domain, TDRD3 DUF1767-OB-fold domains, and their complex reveal that the OB-fold domain of TDRD3 binds the toroidal-shaped catalytic domain of TOP3B. The TDRD3 OB-fold insertion loop and core region both contribute to the interaction; hydrophobic core surface and insertion loop termini are essential. Key structural elements Arg96, Val109, Phe139, and the short insertion loop of TDRD3 confer specificity for TOP3β over the non-cognate TOP3α. Crystal structure determination (3.44 Å complex, 1.62 Å TDRD3 domain, 3.6 Å complex), pull-down binding assays with mutagenesis Scientific reports High 28176834
2021 TDRD3 directly interacts with the DExH-box helicase DHX9 via its Tudor domain, recruiting DHX9 to target gene promoters. DHX9 resolves R-loops at promoters in a helicase-activity-dependent manner. Additionally, TDRD3 stimulates DHX9 helicase activity via its OB-fold domain, which likely binds single-stranded DNA in R-loop structures. Together DHX9 and TOP3B suppress promoter-associated R-loops downstream of TDRD3 recruitment. Co-immunoprecipitation, ChIP, R-loop detection assays (DRIP), helicase activity assays, domain deletion analysis, DHX9 helicase-dead mutant Nucleic acids research High 34329467
2022 TDRD3 localizes to stress granules partly based on the methylation status of G3BP1. TDRD3 overexpression forms granules containing translation components independently of G3BP. TDRD3 is cleaved by enteroviral 2A proteinase. TDRD3 knockdown alters transcriptional regulation of numerous IFN effectors (including recruitment of IRF3, IRF7, TBK1, STING to SGs), establishing TDRD3 as an antiviral restriction factor. Immunofluorescence, knockdown/knockout experiments, viral infection assays, transcriptional analysis, co-localization studies PLoS pathogens Medium 35085371
2023 TDRD3 stabilizes TOP3B by recruiting the deubiquitinase USP9X to form a TDRD3-USP9X complex; inactivation of USP9X destabilizes TOP3B. MIB1 E3 ligase independently mediates TOP3B ubiquitylation and proteasomal degradation by directly interacting with TOP3B independently of TDRD3. The TDRD3-USP9X complex works downstream of MIB1. Loss of TDRD3 increases TOP3B cleavage complexes (TOP3Bccs) in DNA and RNA, induces R-loops, γH2AX, and growth defects. TDRD3 biochemically increases the turnover rate of TOP3B. Co-immunoprecipitation, ubiquitylation assays, TOP3Bcc measurement, γH2AX assays, knockdown/double-knockdown epistasis, DRIP-seq for R-loops, growth assays Nature communications High 37980342
2024 In Tdrd3-null mice, the TOP3B-TDRD3 complex is essential for normal brain function; loss of TDRD3 causes defects in cognitive behaviors, synaptic plasticity, adult neurogenesis, and neuronal activity-dependent transcription. Multiple neurodevelopmentally critical genes show reduced levels in mature but not nascent transcripts in Tdrd3-null mice, indicating a post-transcriptional (not transcriptional) regulatory role of the complex. Tdrd3-null mouse generation, behavioral assays, electrophysiology (synaptic plasticity), neurogenesis assays, RNA-seq comparing nascent vs. mature transcripts Progress in neurobiology Medium 38216113
2024 PRMT1 methylates stress granule constituent RNA-binding proteins on their RGG motifs, and TDRD3 as an aDMA reader enhances RNA binding to recruit additional RNAs and RBPs, thereby lowering the percolation threshold and promoting stress granule assembly. Methylation assays, stress granule formation assays, RNA-binding assays, deletion/mutation analysis International journal of biological macromolecules Medium 39097054
2024 TDRD3 contains UBA and LC3-interacting region (LIR) motifs similar to selective autophagy receptor p62/SQSTM1. KO of TDRD3 reduces starvation-induced autophagy; reintroduction restores it dose-dependently. TDRD3 levels decrease during autophagy (consistent with receptor turnover). The LIR3 motif of TDRD3 mediates interaction with LC3B (shown by Co-IP and colocalization). TDRD3 LIR motifs also regulate SG condensation, SG decay rate upon stress release, and SG formation kinetics. TDRD3 KO/rescue experiments, autophagy flux assays, co-immunoprecipitation (LIR3-LC3B), immunofluorescence/super-resolution microscopy, deletion mutant analysis bioRxivpreprint Low 39345463
2018 NMR fragment screening identified 14 small molecule hits against the TDRD3 Tudor domain aromatic cage. Crystal structure of the TDRD3 Tudor domain with hit 1 reveals it protrudes into the aromatic cage, inducing a distinct binding mode with aromatic residues tilting to accommodate π-π stacking and N596 side chain rotating 3.1 Å to form a hydrogen bond. This structural plasticity distinguishes TDRD3 from SMN, 53BP1, and SND1 Tudor domains. NMR fragment-based screening, competitive fluorescence polarization, ITC, crystal structure determination (PDB: 5YJ8) The FEBS journal High 29645362
2026 In Treg-specific Tdrd3-knockout mice, TDRD3 is required for iTreg (but not thymic Treg) differentiation. Mechanistically, TDRD3 is recruited by transcription factor FOXO1 (presumably in a methylation-dependent manner) to activate Klf2 expression, which is essential for Treg differentiation. Enforced Klf2 expression in Tdrd3-deficient CD4+ T cells rescues both iTreg development and suppressive function. Treg-specific conditional Tdrd3 knockout mouse, adoptive transfer colitis model, Klf2 rescue by enforced expression, ChIP/transcriptional analysis Science advances Medium 41576154

Source papers

Stage 0 corpus · 18 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 TDRD3 is an effector molecule for arginine-methylated histone marks. Molecular cell 182 21172665
2008 TDRD3, a novel Tudor domain-containing protein, localizes to cytoplasmic stress granules. Human molecular genetics 99 18632687
2012 Crystal structure of TDRD3 and methyl-arginine binding characterization of TDRD3, SMN and SPF30. PloS one 72 22363433
2008 Tdrd3 is a novel stress granule-associated protein interacting with the Fragile-X syndrome protein FMRP. Human molecular genetics 68 18664458
2021 TDRD3 promotes DHX9 chromatin recruitment and R-loop resolution. Nucleic acids research 52 34329467
2012 Recognition of asymmetrically dimethylated arginine by TDRD3. Nucleic acids research 36 23066109
2017 Arginine methylation of USP9X promotes its interaction with TDRD3 and its anti-apoptotic activities in breast cancer cells. Cell discovery 31 28101374
2017 Structural basis of the interaction between Topoisomerase IIIβ and the TDRD3 auxiliary factor. Scientific reports 29 28176834
2022 TDRD3 is an antiviral restriction factor that promotes IFN signaling with G3BP1. PLoS pathogens 26 35085371
2018 Structural plasticity of the TDRD3 Tudor domain probed by a fragment screening hit. The FEBS journal 19 29645362
2024 Tdrd3-null mice show post-transcriptional and behavioral impairments associated with neurogenesis and synaptic plasticity. Progress in neurobiology 15 38216113
2023 The TDRD3-USP9X complex and MIB1 regulate TOP3B homeostasis and prevent deleterious TOP3B cleavage complexes. Nature communications 15 37980342
2024 PRMT1 and TDRD3 promote stress granule assembly by rebuilding the protein-RNA interaction network. International journal of biological macromolecules 4 39097054
2023 Tdrd3-null mice show post-transcriptional and behavioral impairments associated with neurogenesis and synaptic plasticity. Research square 4 36909584
2023 Crystal structure of Tudor domain of TDRD3 in complex with a small molecule antagonist. Biochimica et biophysica acta. Gene regulatory mechanisms 4 37499935
2024 TDRD3 functions as a selective autophagy receptor with dual roles in autophagy and modulation of stress granule stability. bioRxiv : the preprint server for biology 2 39345463
2023 Involvement of SYCP2L and TDRD3 gene variants on ovarian reserve and reproductive outcomes: a cross-sectional study. JBRA assisted reproduction 2 37417852
2026 TDRD3, a Tudor domain-containing protein, regulates Klf2-dependent Treg differentiation and function to modulate immune tolerance. Science advances 1 41576154

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