Affinage

HECTD3

E3 ubiquitin-protein ligase HECTD3 · UniProt Q5T447

Length
861 aa
Mass
97.1 kDa
Annotated
2026-06-10
21 papers in source corpus 18 papers cited in narrative 18 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

HECTD3 is a HECT-domain E3 ubiquitin ligase that controls inflammatory signaling, apoptosis resistance, and tumor cell behavior by assembling predominantly non-degradative polyubiquitin chains on a range of signaling proteins (PMID:24287696, PMID:29920190, PMID:30741923). It engages substrates through an N-terminal DOC domain and transfers ubiquitin via a catalytic cysteine in its HECT domain (C823/C832), as demonstrated by catalytic-site mutagenesis that abolishes substrate ubiquitination (PMID:33627626, PMID:35397617, PMID:36088509). A recurring theme is the building of atypical, signal-modifying chains: K63-linked ubiquitination of TRAF3 at K138 to drive TRAF3-TBK1 complex formation and type I interferon induction during bacterial infection (PMID:29920190), K27/K29-linked modification of MALT1 (K648) and K27-linked modification of STAT3 (K180) to promote NF-κB activation, STAT3 Tyr705 phosphorylation, and pathogenic Th17 differentiation (PMID:30741923), K27/K63-linked ubiquitination of IKKα at K296 to enhance its nuclear kinase activity and tumor metastasis (PMID:35918322), and K33-linked ubiquitination of PKR that blocks PKR dimerization and eIF2α activation while redirecting PKR into an IKK-associated inflammatory complex (PMID:37402711). HECTD3 also restrains apoptosis: it K63-ubiquitinates caspase-8 at K215 to limit its activation and TRAIL-induced death in an E3-activity-dependent manner (PMID:24287696), and ubiquitinates caspase-9 to block its oligomerization and Apaf-1 association, a function gated by ERK-mediated phosphorylation of HECTD3 at Thr-157 (PMID:28716524). In addition to stabilizing or activating substrates, HECTD3 directs selected proteins to proteasomal degradation, including the HSP90 client kinases CRAF, MASTL, and LKB1 (PMID:28636940) and the cystine transporter SLC7A11, the latter sensitizing colon cancer cells to ferroptosis (PMID:37422058). Through these activities HECTD3 promotes c-MYC- and PARP1-dependent tumor proliferation and DNA repair (PMID:35397617, PMID:36088509), links to p62 ubiquitination and autophagy (PMID:39487119), and is itself a pharmacological target via the HECTD3/UbcH5b inhibitor PC3-15 (PMID:39487119).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2008 Medium

    Established HECTD3 as a functional E3 ligase by identifying its first substrate, defining a degradative mode of action linked to mitotic spindle integrity.

    Evidence Yeast two-hybrid, reciprocal Co-IP, in vitro binding, siRNA, and ubiquitination assays on Tara (also Syntaxin 8 in a parallel study)

    PMID:18194665 PMID:18821010

    Open questions at the time
    • Ubiquitin chain linkage on Tara not defined
    • Catalytic residue dependence not tested
    • Syntaxin 8 interaction lacked functional readout or mutagenesis
  2. 2013 High

    Revealed HECTD3's non-degradative ubiquitination mode and its anti-apoptotic role, showing it stabilizes MALT1 and ubiquitinates caspase-8 at K215 to blunt death receptor signaling.

    Evidence Y2H/DOC-domain mapping, Co-IP, linkage and site-specific ubiquitination, K215 and ligase-dead mutagenesis, TRAIL apoptosis and rescue assays

    PMID:23358872 PMID:24287696

    Open questions at the time
    • Endogenous chain-type confirmation for MALT1 in this work
    • How non-degradative chains mechanistically block caspase-8 activation not resolved structurally
  3. 2017 Medium

    Defined two opposing branches of HECTD3 function—DOC-domain-dependent degradation of HSP90 client kinases versus ERK-phosphorylation-gated suppression of caspase-9 apoptosis.

    Evidence siRNA screen, Co-IP, DOC-domain mapping, proteasomal degradation assays (CRAF/MASTL/LKB1); caspase-9 oligomerization/Apaf-1 assays, T157A mutant, ERK kinase assay, xenografts

    PMID:28636940 PMID:28716524

    Open questions at the time
    • Chain linkages on client kinases and caspase-9 not specified
    • Structural basis of DOC-domain client recognition unresolved
    • How Thr-157 phosphorylation alters ligase activity not mechanistically defined
  4. 2018 High

    Demonstrated HECTD3 drives innate antibacterial immunity through K63-linked TRAF3 ubiquitination enabling TRAF3-TBK1 complex assembly and type I IFN.

    Evidence Hectd3 knockout mice, in vitro ubiquitination with K138 mutagenesis, Co-IP of TRAF3-TBK1, Francisella/Mycobacterium/Listeria infection models

    PMID:29920190

    Open questions at the time
    • E2 partner in this context not identified
    • Structural detail of K63-chain placement on TRAF3 not resolved
  5. 2019 High

    Showed HECTD3 builds K27/K29 chains on MALT1 and K27 chains on STAT3 to coordinately activate NF-κB and STAT3 and drive pathogenic Th17 autoimmunity.

    Evidence EAE knockout mouse model, linkage-specific ubiquitination, K648 MALT1 and K180 STAT3 mutagenesis, STAT3 phosphorylation and Th17 differentiation assays

    PMID:30741923

    Open questions at the time
    • How K27/K29 chains are read by downstream effectors not defined
    • Whether MALT1 and STAT3 modification are coupled events unclear
  6. 2021 Medium

    Confirmed and extended the TRAF3 mechanism, mapping dual DOC/HECT engagement of TRAF3 and catalytic Cys832 dependence in oxidative stress-driven ischemia-reperfusion injury.

    Evidence Domain mapping, Co-IP, ubiquitination assays, Cys832 mutagenesis, hypoxia/reoxygenation and rat DCD liver models

    PMID:33627626

    Open questions at the time
    • Tissue-specific regulation of HECTD3 in this context not defined
    • Single-lab in vivo model
  7. 2022 High

    Expanded the substrate repertoire across cancer contexts, establishing catalytic-cysteine-dependent ubiquitination of c-MYC (K29), PARP1 (K63, K209/K221), and IKKα (K27/K63, K296) to promote proliferation, DNA repair, and metastasis.

    Evidence Co-IP, DOC-domain mapping, linkage/site-specific ubiquitination, C823 and substrate-lysine mutagenesis, kinase activity and nuclear fractionation, conditional knockout/knockin mice and xenografts

    PMID:35397617 PMID:35918322 PMID:36088509

    Open questions at the time
    • Upstream signals selecting among these substrates not fully defined
    • Whether one E2 supports all linkage types unknown
  8. 2022 Low

    Linked HECTD3-MALT1 and HECTD3-LKB1 axes to disease phenotypes (neuronal glucose toxicity, glioma radioresistance) via epistasis, implicating JNK and ZEB1 as downstream effectors.

    Evidence siRNA, knockout rat/xenograft models, western blot, MALT1 and ZEB1 overexpression rescue

    PMID:35768187 PMID:35913790

    Open questions at the time
    • Ubiquitin linkage and site on LKB1 in this context not defined
    • Mechanism of MALT1 stabilization indirect
    • Epistasis inferred from rescue rather than direct biochemistry
  9. 2023 High

    Identified a novel K33-linked ubiquitination of PKR and a degradative role on SLC7A11, broadening HECTD3 control to antiviral/inflammatory signaling and ferroptosis.

    Evidence K33-linkage-specific ubiquitination, PKR dimerization/phosphorylation/eIF2α and PKR-IKK complex assays, knockout mouse and viral model; SLC7A11 C823 mutagenesis, half-life and ferroptosis assays, xenografts

    PMID:37402711 PMID:37422058

    Open questions at the time
    • Structural basis distinguishing K33 vs degradative chains on different substrates unknown
    • Determinants of degradative versus non-degradative outcome unresolved
  10. 2024 Medium

    Defined a specific E2-E3 pairing (UbcH5b) and a druggable axis, linking HECTD3 to p62 ubiquitination, autophagy, and DNA damage repair through nuclear p62/RNF168 control.

    Evidence Co-IP, ubiquitination with UbcH5b, subcellular fractionation, DNA repair assays, PC3-15 inhibitor, HECTD3 knockout cells

    PMID:39487119

    Open questions at the time
    • p62 chain linkage not specified
    • Generality of UbcH5b across other substrates not tested
  11. 2025 Medium

    Established phosphodegron-based substrate recognition, showing AKT1 phosphorylation of CMTM3 at Ser181 licenses HECTD3-mediated degradation.

    Evidence Co-IP, ubiquitination, S181A CMTM3 mutagenesis, AKT1 kinase assay, PI3K/AKT inhibition, xenografts

    PMID:40836897

    Open questions at the time
    • Whether DOC domain directly reads phospho-Ser181 not structurally shown
    • Chain linkage on CMTM3 not defined

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural determinants that allow HECTD3 to choose between non-degradative (K27/K29/K33/K63) and degradative chain assembly on different substrates, and how DOC-domain engagement and Thr-157 phosphorylation specify these outcomes, remain unresolved.
  • No structure of HECTD3 DOC or HECT domain with substrate
  • Linkage-specificity mechanism undefined
  • Full E2 enzyme repertoire across substrates unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016740 transferase activity 8 GO:0016874 ligase activity 7 GO:0140096 catalytic activity, acting on a protein 7
Localization
GO:0005634 nucleus 2 GO:0005829 cytosol 2
Pathway
R-HSA-392499 Metabolism of proteins 5 R-HSA-162582 Signal Transduction 3 R-HSA-168256 Immune System 3 R-HSA-5357801 Programmed Cell Death 3
Partners
C-MYCCASPASE-8IKKΑMALT1PKRSTAT3TRAF3UBCH5B

Evidence

Reading pass · 18 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2008 HECTD3 directly binds Tara in vitro and forms a complex with Tara in vivo; overexpression of HECTD3 enhances ubiquitination of Tara and promotes its proteasomal turnover, while HECTD3 depletion decreases Tara degradation and leads to multipolar spindle formation. Yeast two-hybrid, co-immunoprecipitation, in vitro binding, siRNA knockdown, ubiquitination assay Biochemical and biophysical research communications Medium 18194665
2008 HECTD3 interacts with Syntaxin 8 (identified by yeast two-hybrid) and co-immunoprecipitation confirms direct interaction; overexpression of HECTD3 promotes ubiquitination of Syntaxin 8; HECTD3 and Syntaxin 8 share similar subcellular localization by immunofluorescence. Yeast two-hybrid, co-immunoprecipitation, immunofluorescence, ubiquitination assay Cellular and molecular neurobiology Low 18821010
2013 HECTD3 interacts with MALT1 via its N-terminal DOC domain (identified by yeast two-hybrid), promotes non-degradative polyubiquitination of MALT1, stabilizes MALT1 protein levels, and HECTD3 depletion decreases MALT1 and increases cisplatin-induced apoptosis; MALT1 overexpression partially rescues HECTD3 depletion-induced apoptosis. Yeast two-hybrid, co-immunoprecipitation, ubiquitination assay, siRNA knockdown, overexpression rescue, domain mapping Neoplasia Medium 23358872
2013 HECTD3 interacts with caspase-8 death effector domains and ubiquitinates caspase-8 with K63-linked polyubiquitin chains at K215, which does not target caspase-8 for degradation but decreases caspase-8 activation; mutation of K215 abolishes HECTD3-mediated protection from TRAIL-induced caspase-8 cleavage; HECTD3 inhibits TRAIL-induced apoptosis in an E3 ligase activity-dependent manner. Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis (K215 caspase-8), E3 ligase-dead mutant, TRAIL apoptosis assay Cell death & disease High 24287696
2017 HECTD3 associates with HSP90 and CRAF in cells via its N-terminal DOC domain; HECTD3 is required for proteasomal degradation of the HSP90 client kinase CRAF (and also MASTL and LKB1) upon HSP90 ATPase inhibition; this DOC domain is mutationally disrupted in tumor cells with activated MAP kinase signaling. siRNA screen, co-immunoprecipitation, domain mapping (DOC domain), proteasomal degradation assay, tumor cell mutation analysis Cell reports Medium 28636940
2017 HECTD3 binds and ubiquitinates caspase-9, inhibiting caspase-9 oligomerization and its association with Apaf-1, thereby suppressing caspase-9 activation; this antiapoptotic function requires phosphorylation of HECTD3 at Thr-157 by ERK, as the T157A mutant is non-functional. Co-immunoprecipitation, ubiquitination assay, caspase-9 oligomerization assay, Apaf-1 interaction assay, site-directed mutagenesis (T157A), ERK kinase assay, xenograft model Cancer letters Medium 28716524
2018 HECTD3 mediates K63-linked polyubiquitination of TRAF3 at residue K138 via its catalytic HECT domain; this ubiquitination enables TRAF3-TBK1 complex formation and type I IFN induction during intracellular bacterial infection; Hectd3-deficient mice have impaired type I IFN response and enhanced bacterial clearance. Knockout mouse model, in vitro ubiquitination assay, site-directed mutagenesis (K138 TRAF3), co-immunoprecipitation (TRAF3-TBK1 complex), infection models (Francisella, Mycobacterium, Listeria) The Journal of clinical investigation High 29920190
2019 HECTD3 promotes K27-linked and K29-linked polyubiquitination of MALT1 (at K648) and K27-linked polyubiquitination of STAT3 (at K180); these non-degradative modifications promote STAT3 tyrosine-705 activating phosphorylation, NF-κB activation via MALT1, and pathogenic Th17 cell differentiation in EAE. Knockout mouse model (EAE), ubiquitination assay with linkage-specific analysis, site-directed mutagenesis (K648 MALT1, K180 STAT3), phosphorylation assay, Th17 differentiation assay Nature communications High 30741923
2021 Both the DOC and HECT domains of HECTD3 directly interact with TRAF3; the catalytic Cys832 in the HECT domain promotes K63-linked polyubiquitination of TRAF3 at Lys138, increasing oxidative stress and activating NF-κB to induce ischemia-reperfusion injury. Domain mapping (DOC and HECT domains), co-immunoprecipitation, ubiquitination assay, Cys832 mutagenesis, hypoxia/reoxygenation cell model, rat DCD liver model Cell death & disease Medium 33627626
2022 HECTD3 promotes K29-linked polyubiquitination of c-MYC through interaction between its DOC domain and the CP/bHLHZ domains of c-MYC; mutation of the catalytic Cys823 of HECTD3 reduces c-MYC polyubiquitination; this modification promotes gastric cancer cell proliferation. Co-immunoprecipitation, domain mapping, ubiquitination assay, site-directed mutagenesis (C823A HECTD3), cell proliferation assay Cell death discovery Medium 35397617
2022 HECTD3 promotes K63-linked polyubiquitination of PARP1 (at K209 and K221) via interaction between its DOC domain and the DNA-binding domain of PARP1, stabilizing PARP1 expression; Cys823 mutation of HECTD3 reduces PARP1 polyubiquitination; EGFR-mediated signaling activates this process in glioblastoma. Co-immunoprecipitation, domain mapping, ubiquitination assay, site-directed mutagenesis (C823 HECTD3, K209/K221 PARP1), xenograft mouse model British journal of cancer Medium 36088509
2022 HECTD3 promotes stabilization of MALT1 to regulate JNK pathway (c-JUN/p-JNK upregulation) in high-glucose conditions; MALT1 overexpression attenuates neuroprotective effects of HECTD3 silencing, placing MALT1 downstream of HECTD3 in neuronal glucose toxicity. siRNA knockdown, HECTD3 knockout rat model, western blot, overexpression rescue (MALT1) Archives of physiology and biochemistry Low 35913790
2022 HECTD3 promotes K27- and K63-linked polyubiquitination of IKKα at K296, stabilizing IKKα, promoting its nuclear localization and kinase activity, increasing H3 phosphorylation and NF-κB target gene transcription; endothelial HECTD3 knockout reduces tumor cell adhesion and lung colonization. Co-immunoprecipitation, ubiquitination assay with linkage-specific analysis, site-directed mutagenesis (K296 IKKα), nuclear fractionation, kinase activity assay, conditional knockout/knockin mouse models, metastasis assays Signal transduction and targeted therapy High 35918322
2022 HECTD3 ubiquitinates LKB1 and positively regulates ZEB1 expression through LKB1 ubiquitination; ZEB1 overexpression abolishes the effects of HECTD3 knockdown on radiation resistance and migration in glioma cells, placing ZEB1 downstream of HECTD3-mediated LKB1 ubiquitination. siRNA knockdown, ubiquitination assay, overexpression rescue (ZEB1), xenograft mouse model The European journal of neuroscience Low 35768187
2023 HECTD3 interacts with PKR and mediates K33-linked polyubiquitination of PKR (first identified non-proteolytic ubiquitin modification for PKR); this disrupts PKR dimerization and phosphorylation, preventing EIF2α activation (accelerating viral replication) while promoting PKR-IKK complex formation and inflammatory response. Co-immunoprecipitation, ubiquitination assay with K33-linkage-specific analysis, PKR dimerization assay, phosphorylation assay, EIF2α activation assay, PKR-IKK complex co-IP, HECTD3-deficient mouse model, viral infection model Cell death & disease High 37402711
2023 HECTD3 promotes polyubiquitination and proteasomal degradation of SLC7A11; mutation of the catalytic Cys823 impairs SLC7A11 polyubiquitination; HECTD3 suppresses SLC7A11-mediated cystine uptake, enhancing ferroptosis in colon cancer cells. Co-immunoprecipitation, ubiquitination assay, Cys823 mutagenesis, protein half-life assay, ferroptosis assay, xenograft model Experimental cell research Medium 37422058
2024 HECTD3 collaborates with UbcH5b (E2 enzyme) to promote p62 ubiquitination and autophagy; HECTD3 deletion leads to p62 accumulation in the nucleus after irradiation, inhibiting RNF168-mediated DNA damage repair; the HECTD3/UbcH5b inhibitor PC3-15 blocks DNA damage repair and increases radiosensitivity. Co-immunoprecipitation, ubiquitination assay (with UbcH5b), subcellular fractionation (nuclear p62 accumulation), DNA damage repair assay, small molecule inhibitor (PC3-15), HECTD3 knockout cell lines Cell death discovery Medium 39487119
2025 HECTD3 ubiquitinates AKT-phosphorylated CMTM3 targeting it for proteasomal degradation; AKT1 directly phosphorylates CMTM3 at Ser181, and this phosphorylation is required for HECTD3 recognition; knockdown of HECTD3 or PI3K/AKT inhibition stabilizes CMTM3; non-phosphorylatable CMTM3-S181A resists HECTD3-mediated degradation. Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis (S181A CMTM3), kinase assay (AKT1), pharmacological PI3K/AKT inhibition, xenograft model Carcinogenesis Medium 40836897

Source papers

Stage 0 corpus · 21 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 Hectd3 promotes pathogenic Th17 lineage through Stat3 activation and Malt1 signaling in neuroinflammation. Nature communications 71 30741923
2013 The HECTD3 E3 ubiquitin ligase facilitates cancer cell survival by promoting K63-linked polyubiquitination of caspase-8. Cell death & disease 56 24287696
2018 HECTD3 mediates TRAF3 polyubiquitination and type I interferon induction during bacterial infection. The Journal of clinical investigation 53 29920190
2016 MiR-153 promotes breast cancer cell apoptosis by targeting HECTD3. American journal of cancer research 41 27508098
2013 The HECTD3 E3 ubiquitin ligase suppresses cisplatin-induced apoptosis via stabilizing MALT1. Neoplasia (New York, N.Y.) 37 23358872
2021 Hypothermic oxygenated perfusion inhibits HECTD3-mediated TRAF3 polyubiquitination to alleviate DCD liver ischemia-reperfusion injury. Cell death & disease 30 33627626
2019 The role of E3 ubiquitin ligase HECTD3 in cancer and beyond. Cellular and molecular life sciences : CMLS 30 31637449
2022 Targeting HECTD3-IKKα axis inhibits inflammation-related metastasis. Signal transduction and targeted therapy 29 35918322
2008 The E3 ubiquitin ligase HECTD3 regulates ubiquitination and degradation of Tara. Biochemical and biophysical research communications 28 18194665
2017 HECTD3 Mediates an HSP90-Dependent Degradation Pathway for Protein Kinase Clients. Cell reports 22 28636940
2017 Down-regulation of HECTD3 by HER2 inhibition makes serous ovarian cancer cells sensitive to platinum treatment. Cancer letters 22 28989055
2017 The E3 ligase HECTD3 promotes esophageal squamous cell carcinoma (ESCC) growth and cell survival through targeting and inhibiting caspase-9 activation. Cancer letters 21 28716524
2023 E3 ubiquitin ligase HECTD3 is a tumor suppressor and mediates the polyubiquitination of SLC7A11 to promote ferroptosis in colon cancer. Experimental cell research 17 37422058
2022 HECTD3 promotes gastric cancer progression by mediating the polyubiquitination of c-MYC. Cell death discovery 17 35397617
2022 HECTD3 regulates the tumourigenesis of glioblastoma by polyubiquitinating PARP1 and activating EGFR signalling pathway. British journal of cancer 16 36088509
2008 Interaction between syntaxin 8 and HECTd3, a HECT domain ligase. Cellular and molecular neurobiology 12 18821010
2023 E3 ligase HECTD3 promotes RNA virus replication and virus-induced inflammation via K33-linked polyubiquitination of PKR. Cell death & disease 11 37402711
2022 HECTD3 promotes NLRP3 inflammasome and pyroptosis to exacerbate diabetes-related cognitive impairment by stabilising MALT1 to regulate JNK pathway. Archives of physiology and biochemistry 10 35913790
2024 Targeting the HECTD3-p62 axis increases the radiosensitivity of triple negative breast cancer cells. Cell death discovery 7 39487119
2022 HECTD3 enhances cell radiation resistance and migration by regulating LKB1 mediated ZEB1 in glioma. The European journal of neuroscience 3 35768187
2025 HECTD3 E3 ligase mediates ubiquitination of AKT-phosphorylated CMTM3 in HER2-overexpressed breast cancer cells. Carcinogenesis 0 40836897

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