{"gene":"KBTBD7","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2015,"finding":"KBTBD7 (together with KBTBD6) functions as a substrate adaptor for a CUL3 RING ubiquitin ligase complex that mediates ubiquitylation and proteasomal degradation of TIAM1, a RAC1-specific GEF. Depletion of KBTBD6/7 elevates TIAM1 abundance, increases RAC1 activity, alters actin morphology, causes loss of focal adhesions, reduces proliferation, and enhances invasion. KBTBD7 employs ATG8 family-interacting motifs to bind preferentially to GABARAP proteins, and ubiquitylation of TIAM1 by CUL3-KBTBD6/KBTBD7 depends on GABARAP binding, revealing that recruitment to GABARAP-containing vesicles spatially restricts RAC1 signaling.","method":"Co-immunoprecipitation, ubiquitylation assays, siRNA knockdown with actin morphology/invasion/proliferation readouts, ATG8-family binding motif mutagenesis, vesicle recruitment assays","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, ubiquitylation assays, multiple orthogonal functional readouts (actin, invasion, proliferation), domain mutagenesis, independently described in companion commentary (PMID:27308540)","pmids":["25684205","27308540"],"is_preprint":false},{"year":2021,"finding":"KBTBD7 acts as an E3 ligase that is recruited by p97/VCP via UBA-UBX adaptors to promote ubiquitination and ERAD (endoplasmic reticulum-associated degradation) of the Wnt/PCP core components Vangl1 and Vangl2. Wnt5a/CK1-induced phosphorylation of Vangl prevents its ubiquitination by KBTBD7 and facilitates its export from the ER to the plasma membrane. In vivo, KBTBD7 regulates convergent extension during zebrafish gastrulation, consistent with its role in controlling Vangl abundance.","method":"Co-immunoprecipitation (p97/VCP–KBTBD7 and KBTBD7–Vangl interactions), ubiquitination assays, ERAD assays, phosphorylation-blocking mutants, zebrafish convergent-extension phenotype rescue/loss-of-function","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, phospho-mutant epistasis, in vivo zebrafish), single lab but rigorous multi-method approach","pmids":["33990333"],"is_preprint":false},{"year":2020,"finding":"KBTBD7 directly interacts with and ubiquitinates dopamine type 2 receptor (DRD2) at five specific lysine residues (K221, K226, K241, K251, K258), targeting internalized DRD2 for proteasomal degradation. KBTBD7 knockout mice show elevated DRD2 protein in pituitary, thalamus, and heart. KBTBD7-mediated DRD2 degradation attenuates cabergoline-induced inhibition of the AKT/mTOR pathway, and knockdown of KBTBD6/7 sensitizes pituitary tumor cells to dopamine agonist treatment.","method":"Yeast two-hybrid, Co-IP, ubiquitination site mapping, CRISPR-Cas9 knockout mice with DRD2 protein quantification, cell-based knockdown/overexpression with AKT/mTOR signaling readouts","journal":"Acta neuropathologica","confidence":"High","confidence_rationale":"Tier 2 / Strong — yeast two-hybrid plus Co-IP plus site-specific ubiquitination mapping plus in vivo KO mouse validation, multiple orthogonal methods in single study","pmids":["32572597"],"is_preprint":false},{"year":2018,"finding":"KBTBD7 is a direct target of miR-21 (validated by luciferase reporter assay) and promotes DAMP-triggered inflammatory responses in macrophages. KBTBD7 physically interacts with MKK3/6 and promotes their activation, which in turn enhances downstream p38 and NF-κB signaling induced by DAMPs (HMGB1 and HSP60). miR-21 deficiency elevates KBTBD7 expression and exacerbates this signaling axis post-MI.","method":"Luciferase reporter assay (miR-21 targeting of KBTBD7 3'UTR), Co-immunoprecipitation (KBTBD7–MKK3/6 interaction), miR-21 knockout mice, siRNA knockdown with cytokine and phospho-signaling readouts","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for KBTBD7–MKK3/6 interaction plus luciferase validation plus KO mouse, single lab, multiple methods","pmids":["29991775"],"is_preprint":false},{"year":2022,"finding":"KBTBD7 promotes ubiquitin-dependent proteasomal degradation of PTEN in non-small cell lung cancer cells, thereby activating EGFR/PI3K/AKT signaling and promoting cell proliferation and invasion.","method":"KBTBD7 knockdown in NSCLC cell lines with PTEN protein level measurement, ubiquitination assays, downstream signaling (AKT) and proliferation/invasion readouts","journal":"Cancer medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — knockdown plus ubiquitination assay plus signaling readouts, single lab, single study","pmids":["35499228"],"is_preprint":false},{"year":2024,"finding":"KBTBD7 acts as an E3 ubiquitin ligase that directly binds KLF15 transcription factor (confirmed by Co-IP) and catalyzes its ubiquitination and proteasomal degradation. Loss of KBTBD7 in LPS-treated microglia stabilizes KLF15, suppresses NLRP3 inflammasome and NF-κB signaling activation, and reduces pro-inflammatory cytokine release; KLF15 knockdown abolishes this anti-inflammatory effect.","method":"Co-immunoprecipitation (KBTBD7–KLF15), ubiquitination assays, siRNA knockdown with NLRP3/NF-κB signaling readouts, epistasis rescue experiment (KLF15 KD reverting KBTBD7 KD phenotype)","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus ubiquitination assay plus epistasis rescue, single lab, single study","pmids":["39489209"],"is_preprint":false},{"year":2024,"finding":"KBTBD7 interacts with FOXA1 and promotes FOXA1 expression, which indirectly inhibits SLC7A11 transcription; this axis drives ferroptosis and mitochondrial dysfunction in LPS-treated alveolar epithelial cells. KBTBD7 knockdown reduces ROS production, ferroptosis markers, and inflammatory cytokines in vitro and in a septic lung injury mouse model.","method":"Co-immunoprecipitation (KBTBD7–FOXA1), siRNA knockdown in LPS-induced cells and in vivo CLP model with ferroptosis/ROS/cytokine readouts","journal":"International immunopharmacology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP plus knockdown phenotype, single lab, mechanistic link to SLC7A11 inferred indirectly","pmids":["38652964"],"is_preprint":false},{"year":2010,"finding":"KBTBD7 protein (684 aa, 77 kDa) localizes to the cytoplasm in COS-7 cells. When fused to a GAL4 DNA-binding domain, KBTBD7 activates transcription; deletion analysis shows the BTB domain and kelch repeat motif are the main regions for transcriptional activation. Overexpression in MCF-7 cells activates AP-1 and SRE transcriptional activities, an effect reversed by siRNA knockdown.","method":"Western blot (expression/localization), GAL4-fusion transcription assay, deletion constructs, AP-1/SRE luciferase reporter assays, siRNA knockdown","journal":"BMB reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — multiple reporter assays and domain deletion analysis, single lab, no endogenous protein functional validation","pmids":["20132730"],"is_preprint":false}],"current_model":"KBTBD7 is a BTB-kelch domain-containing substrate adaptor for CUL3 RING ubiquitin ligase complexes that targets multiple substrates—including TIAM1, Vangl1/2, DRD2, PTEN, and KLF15—for ubiquitination and proteasomal degradation; through TIAM1 degradation it spatially restricts RAC1 signaling at GABARAP-containing vesicles, through Vangl degradation it controls Wnt/PCP signaling and convergent extension, and through interaction with MKK3/6 it promotes p38 and NF-κB inflammatory signaling downstream of DAMPs."},"narrative":{"mechanistic_narrative":"KBTBD7 is a BTB-kelch substrate adaptor that confers target specificity on CUL3 RING ubiquitin ligase complexes, directing multiple substrates to ubiquitin-dependent proteasomal degradation [PMID:25684205, PMID:27308540]. Acting with its paralog KBTBD6, it ubiquitylates the RAC1-specific GEF TIAM1; loss of KBTBD7 stabilizes TIAM1, elevates RAC1 activity, remodels actin, and enhances invasion, and its preferential binding to GABARAP via ATG8-interacting motifs spatially restricts this RAC1 signaling to GABARAP-containing vesicles [PMID:25684205, PMID:27308540]. In the Wnt/PCP pathway, KBTBD7 is recruited by p97/VCP through UBA-UBX adaptors to ubiquitinate the core components Vangl1 and Vangl2 for ER-associated degradation, a step blocked by Wnt5a/CK1-induced Vangl phosphorylation, and it regulates convergent extension during zebrafish gastrulation [PMID:33990333]. It additionally targets internalized DRD2 at five mapped lysines, controlling DRD2 abundance in vivo and modulating AKT/mTOR responses to dopamine agonists [PMID:32572597], and degrades PTEN to activate EGFR/PI3K/AKT signaling in lung cancer cells [PMID:35499228]. Independently of its adaptor function, KBTBD7 physically interacts with MKK3/6 to promote p38 and NF-κB inflammatory signaling downstream of DAMPs, and it is a direct target of miR-21 [PMID:29991775]; it also drives inflammatory programs through ubiquitination of the transcription factor KLF15 [PMID:39489209].","teleology":[{"year":2010,"claim":"Initial characterization established KBTBD7 as a cytoplasmic BTB-kelch protein capable of modulating transcriptional output, the first functional readout for an otherwise uncharacterized gene.","evidence":"Western blot localization, GAL4-fusion and AP-1/SRE luciferase reporter assays with domain deletions and siRNA in COS-7/MCF-7 cells","pmids":["20132730"],"confidence":"Medium","gaps":["Transcriptional activation measured only via artificial GAL4 fusion and reporter overexpression, not endogenous targets","No molecular mechanism connecting KBTBD7 to AP-1/SRE established","No ubiquitin ligase or substrate-adaptor role yet identified"]},{"year":2015,"claim":"Defined KBTBD7's core molecular identity as a CUL3 substrate adaptor that ubiquitylates TIAM1, resolving how it functions biochemically and linking it to spatial control of RAC1 signaling via GABARAP vesicles.","evidence":"Reciprocal Co-IP, ubiquitylation assays, siRNA with actin/invasion/proliferation readouts, ATG8-binding motif mutagenesis and vesicle recruitment assays","pmids":["25684205","27308540"],"confidence":"High","gaps":["Generality of GABARAP-dependent recruitment to other substrates not tested","Relative contributions of KBTBD6 versus KBTBD7 not fully dissected"]},{"year":2020,"claim":"Extended the substrate repertoire to DRD2 with residue-level resolution and in vivo validation, showing KBTBD7 controls receptor abundance and downstream AKT/mTOR signaling.","evidence":"Yeast two-hybrid, Co-IP, ubiquitination site mapping (K221/226/241/251/258), CRISPR KO mice, cell-based signaling readouts","pmids":["32572597"],"confidence":"High","gaps":["Whether DRD2 ubiquitination uses the same CUL3 complex as TIAM1 not directly shown","Tissue-specific determinants of substrate selection unclear"]},{"year":2021,"claim":"Connected KBTBD7 to ERAD and Wnt/PCP by showing p97/VCP-mediated recruitment drives Vangl1/2 degradation, establishing a phospho-regulated quality-control step controlling planar cell polarity in vivo.","evidence":"Co-IP (p97/VCP–KBTBD7, KBTBD7–Vangl), ubiquitination and ERAD assays, phospho-blocking mutants, zebrafish convergent-extension loss/rescue","pmids":["33990333"],"confidence":"High","gaps":["How VCP-UBX recruitment relates to CUL3 adaptor function not reconciled","Structural basis of phospho-dependent escape from ubiquitination not resolved"]},{"year":2018,"claim":"Revealed a non-degradative signaling role: KBTBD7 binds and activates MKK3/6 to amplify DAMP-triggered p38/NF-κB inflammation, and is itself repressed by miR-21.","evidence":"Luciferase 3'UTR reporter, Co-IP (KBTBD7–MKK3/6), miR-21 KO mice, siRNA with cytokine/phospho-signaling readouts post-MI","pmids":["29991775"],"confidence":"Medium","gaps":["Whether MKK3/6 activation requires ubiquitin ligase activity or is adaptor-independent unclear","Single Co-IP for the KBTBD7–MKK3/6 interaction without structural mapping"]},{"year":2022,"claim":"Added PTEN as a degradation substrate, positioning KBTBD7 as a driver of EGFR/PI3K/AKT signaling in lung cancer.","evidence":"Knockdown in NSCLC lines with PTEN level, ubiquitination assays, AKT/proliferation/invasion readouts","pmids":["35499228"],"confidence":"Medium","gaps":["CUL3 dependence of PTEN ubiquitination not demonstrated","Single-lab, single-study evidence"]},{"year":2024,"claim":"Implicated KBTBD7 in inflammatory regulation through ubiquitination of KLF15 and an interaction with FOXA1, linking it to NLRP3/NF-κB signaling and ferroptosis in injury models.","evidence":"Co-IP (KBTBD7–KLF15, KBTBD7–FOXA1), ubiquitination assays, siRNA with NLRP3/NF-κB and ferroptosis/ROS readouts, epistasis rescue, sepsis/lung injury mouse models","pmids":["39489209","38652964"],"confidence":"Medium","gaps":["FOXA1–SLC7A11 link inferred indirectly (idx 6 is Low confidence)","How KBTBD7 both degrades a transcription factor and stabilizes another (FOXA1) is mechanistically unreconciled","CUL3 dependence not established for KLF15"]},{"year":null,"claim":"It remains unknown how KBTBD7 selects among its diverse substrates and whether its non-degradative kinase-activating and transcriptional roles share a common structural mechanism.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of substrate or CUL3/VCP engagement","Substrate-selection determinants across tissues uncharacterized","Reconciliation of CUL3-adaptor versus VCP-recruited versus MKK3/6-activating activities unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,2,4,5]},{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[1,5]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[7]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,2]}],"complexes":["CUL3-RING ubiquitin ligase complex"],"partners":["TIAM1","GABARAP","VANGL1","VANGL2","VCP","DRD2","MKK3/6","KLF15"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8WVZ9","full_name":"Kelch repeat and BTB domain-containing protein 7","aliases":[],"length_aa":684,"mass_kda":77.2,"function":"As part of the CUL3(KBTBD6/7) E3 ubiquitin ligase complex functions as a substrate adapter for the RAC1 guanine exchange factor (GEF) TIAM1, mediating its 'Lys-48' ubiquitination and proteasomal degradation (PubMed:25684205). By controlling this ubiquitination, regulates RAC1 signal transduction and downstream biological processes including the organization of the cytoskeleton, cell migration and cell proliferation (PubMed:25684205). Ubiquitination of TIAM1 requires the membrane-associated protein GABARAP which may restrict locally the activity of the complex (PubMed:25684205)","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q8WVZ9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KBTBD7","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1165,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KBTBD7","total_profiled":1310},"omim":[{"mim_id":"617739","title":"KELCH REPEAT- AND BTB DOMAIN-CONTAINING PROTEIN 7; KBTBD7","url":"https://www.omim.org/entry/617739"},{"mim_id":"617738","title":"KELCH REPEAT- AND BTB DOMAIN-CONTAINING PROTEIN 6; KBTBD6","url":"https://www.omim.org/entry/617738"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/KBTBD7"},"hgnc":{"alias_symbol":["DKFZP434E2318"],"prev_symbol":[]},"alphafold":{"accession":"Q8WVZ9","domains":[{"cath_id":"3.30.710.10","chopping":"53-167","consensus_level":"medium","plddt":92.6388,"start":53,"end":167},{"cath_id":"-","chopping":"181-310_334-341","consensus_level":"medium","plddt":86.7167,"start":181,"end":341},{"cath_id":"2.120.10.80","chopping":"342-628","consensus_level":"medium","plddt":89.7982,"start":342,"end":628}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WVZ9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WVZ9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WVZ9-F1-predicted_aligned_error_v6.png","plddt_mean":80.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KBTBD7","jax_strain_url":"https://www.jax.org/strain/search?query=KBTBD7"},"sequence":{"accession":"Q8WVZ9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WVZ9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WVZ9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WVZ9"}},"corpus_meta":[{"pmid":"29991775","id":"PMC_29991775","title":"MicroRNA-21 prevents excessive inflammation and cardiac dysfunction after myocardial infarction through targeting KBTBD7.","date":"2018","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/29991775","citation_count":154,"is_preprint":false},{"pmid":"25684205","id":"PMC_25684205","title":"CUL3-KBTBD6/KBTBD7 ubiquitin ligase cooperates with GABARAP proteins to spatially restrict TIAM1-RAC1 signaling.","date":"2015","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/25684205","citation_count":71,"is_preprint":false},{"pmid":"33990333","id":"PMC_33990333","title":"Regulation of Wnt/PCP signaling through p97/VCP-KBTBD7-mediated Vangl ubiquitination and endoplasmic reticulum-associated degradation.","date":"2021","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/33990333","citation_count":40,"is_preprint":false},{"pmid":"32572597","id":"PMC_32572597","title":"The KBTBD6/7-DRD2 axis regulates pituitary adenoma sensitivity to dopamine agonist treatment.","date":"2020","source":"Acta neuropathologica","url":"https://pubmed.ncbi.nlm.nih.gov/32572597","citation_count":29,"is_preprint":false},{"pmid":"31837588","id":"PMC_31837588","title":"Berberine reduces inflammation of human dental pulp fibroblast via miR-21/KBTBD7 axis.","date":"2019","source":"Archives of oral biology","url":"https://pubmed.ncbi.nlm.nih.gov/31837588","citation_count":22,"is_preprint":false},{"pmid":"32248732","id":"PMC_32248732","title":"Mutations of RNF213 are responsible for sporadic cerebral cavernous malformation and lead to a mulberry-like cluster in zebrafish.","date":"2020","source":"Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/32248732","citation_count":16,"is_preprint":false},{"pmid":"39744815","id":"PMC_39744815","title":"Linear ubiquitination at damaged lysosomes induces local NFKB activation and controls cell survival.","date":"2025","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/39744815","citation_count":13,"is_preprint":false},{"pmid":"19527686","id":"PMC_19527686","title":"New TFII-I family target genes involved in embryonic development.","date":"2009","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/19527686","citation_count":13,"is_preprint":false},{"pmid":"20132730","id":"PMC_20132730","title":"KBTBD7, a novel human BTB-kelch protein, activates transcriptional activities of SRE and AP-1.","date":"2010","source":"BMB reports","url":"https://pubmed.ncbi.nlm.nih.gov/20132730","citation_count":12,"is_preprint":false},{"pmid":"38652964","id":"PMC_38652964","title":"Knockdown of KBTBD7 attenuates septic lung injury by inhibiting ferroptosis and improving mitochondrial dysfunction.","date":"2024","source":"International 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Analysis.","date":"2023","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/38137330","citation_count":8,"is_preprint":false},{"pmid":"32046932","id":"PMC_32046932","title":"Bioinformatics enrichment analysis of genes and pathways related to maternal type 1 diabetes associated with adverse fetal outcomes.","date":"2020","source":"Journal of diabetes and its complications","url":"https://pubmed.ncbi.nlm.nih.gov/32046932","citation_count":8,"is_preprint":false},{"pmid":"35499228","id":"PMC_35499228","title":"KBTBD7 promotes non-small cell lung carcinoma progression by enhancing ubiquitin-dependent degradation of PTEN.","date":"2022","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35499228","citation_count":6,"is_preprint":false},{"pmid":"36174000","id":"PMC_36174000","title":"A transcriptome-wide association study of uterine fibroids to identify potential genetic markers and toxic chemicals.","date":"2022","source":"PloS 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research","url":"https://pubmed.ncbi.nlm.nih.gov/39489209","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12820,"output_tokens":2639,"usd":0.039023,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9810,"output_tokens":3296,"usd":0.065725,"stage2_stop_reason":"end_turn"},"total_usd":0.104748,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"KBTBD7 (together with KBTBD6) functions as a substrate adaptor for a CUL3 RING ubiquitin ligase complex that mediates ubiquitylation and proteasomal degradation of TIAM1, a RAC1-specific GEF. Depletion of KBTBD6/7 elevates TIAM1 abundance, increases RAC1 activity, alters actin morphology, causes loss of focal adhesions, reduces proliferation, and enhances invasion. KBTBD7 employs ATG8 family-interacting motifs to bind preferentially to GABARAP proteins, and ubiquitylation of TIAM1 by CUL3-KBTBD6/KBTBD7 depends on GABARAP binding, revealing that recruitment to GABARAP-containing vesicles spatially restricts RAC1 signaling.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitylation assays, siRNA knockdown with actin morphology/invasion/proliferation readouts, ATG8-family binding motif mutagenesis, vesicle recruitment assays\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, ubiquitylation assays, multiple orthogonal functional readouts (actin, invasion, proliferation), domain mutagenesis, independently described in companion commentary (PMID:27308540)\",\n      \"pmids\": [\"25684205\", \"27308540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"KBTBD7 acts as an E3 ligase that is recruited by p97/VCP via UBA-UBX adaptors to promote ubiquitination and ERAD (endoplasmic reticulum-associated degradation) of the Wnt/PCP core components Vangl1 and Vangl2. Wnt5a/CK1-induced phosphorylation of Vangl prevents its ubiquitination by KBTBD7 and facilitates its export from the ER to the plasma membrane. In vivo, KBTBD7 regulates convergent extension during zebrafish gastrulation, consistent with its role in controlling Vangl abundance.\",\n      \"method\": \"Co-immunoprecipitation (p97/VCP–KBTBD7 and KBTBD7–Vangl interactions), ubiquitination assays, ERAD assays, phosphorylation-blocking mutants, zebrafish convergent-extension phenotype rescue/loss-of-function\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, phospho-mutant epistasis, in vivo zebrafish), single lab but rigorous multi-method approach\",\n      \"pmids\": [\"33990333\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"KBTBD7 directly interacts with and ubiquitinates dopamine type 2 receptor (DRD2) at five specific lysine residues (K221, K226, K241, K251, K258), targeting internalized DRD2 for proteasomal degradation. KBTBD7 knockout mice show elevated DRD2 protein in pituitary, thalamus, and heart. KBTBD7-mediated DRD2 degradation attenuates cabergoline-induced inhibition of the AKT/mTOR pathway, and knockdown of KBTBD6/7 sensitizes pituitary tumor cells to dopamine agonist treatment.\",\n      \"method\": \"Yeast two-hybrid, Co-IP, ubiquitination site mapping, CRISPR-Cas9 knockout mice with DRD2 protein quantification, cell-based knockdown/overexpression with AKT/mTOR signaling readouts\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — yeast two-hybrid plus Co-IP plus site-specific ubiquitination mapping plus in vivo KO mouse validation, multiple orthogonal methods in single study\",\n      \"pmids\": [\"32572597\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"KBTBD7 is a direct target of miR-21 (validated by luciferase reporter assay) and promotes DAMP-triggered inflammatory responses in macrophages. KBTBD7 physically interacts with MKK3/6 and promotes their activation, which in turn enhances downstream p38 and NF-κB signaling induced by DAMPs (HMGB1 and HSP60). miR-21 deficiency elevates KBTBD7 expression and exacerbates this signaling axis post-MI.\",\n      \"method\": \"Luciferase reporter assay (miR-21 targeting of KBTBD7 3'UTR), Co-immunoprecipitation (KBTBD7–MKK3/6 interaction), miR-21 knockout mice, siRNA knockdown with cytokine and phospho-signaling readouts\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for KBTBD7–MKK3/6 interaction plus luciferase validation plus KO mouse, single lab, multiple methods\",\n      \"pmids\": [\"29991775\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"KBTBD7 promotes ubiquitin-dependent proteasomal degradation of PTEN in non-small cell lung cancer cells, thereby activating EGFR/PI3K/AKT signaling and promoting cell proliferation and invasion.\",\n      \"method\": \"KBTBD7 knockdown in NSCLC cell lines with PTEN protein level measurement, ubiquitination assays, downstream signaling (AKT) and proliferation/invasion readouts\",\n      \"journal\": \"Cancer medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — knockdown plus ubiquitination assay plus signaling readouts, single lab, single study\",\n      \"pmids\": [\"35499228\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"KBTBD7 acts as an E3 ubiquitin ligase that directly binds KLF15 transcription factor (confirmed by Co-IP) and catalyzes its ubiquitination and proteasomal degradation. Loss of KBTBD7 in LPS-treated microglia stabilizes KLF15, suppresses NLRP3 inflammasome and NF-κB signaling activation, and reduces pro-inflammatory cytokine release; KLF15 knockdown abolishes this anti-inflammatory effect.\",\n      \"method\": \"Co-immunoprecipitation (KBTBD7–KLF15), ubiquitination assays, siRNA knockdown with NLRP3/NF-κB signaling readouts, epistasis rescue experiment (KLF15 KD reverting KBTBD7 KD phenotype)\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus ubiquitination assay plus epistasis rescue, single lab, single study\",\n      \"pmids\": [\"39489209\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"KBTBD7 interacts with FOXA1 and promotes FOXA1 expression, which indirectly inhibits SLC7A11 transcription; this axis drives ferroptosis and mitochondrial dysfunction in LPS-treated alveolar epithelial cells. KBTBD7 knockdown reduces ROS production, ferroptosis markers, and inflammatory cytokines in vitro and in a septic lung injury mouse model.\",\n      \"method\": \"Co-immunoprecipitation (KBTBD7–FOXA1), siRNA knockdown in LPS-induced cells and in vivo CLP model with ferroptosis/ROS/cytokine readouts\",\n      \"journal\": \"International immunopharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP plus knockdown phenotype, single lab, mechanistic link to SLC7A11 inferred indirectly\",\n      \"pmids\": [\"38652964\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KBTBD7 protein (684 aa, 77 kDa) localizes to the cytoplasm in COS-7 cells. When fused to a GAL4 DNA-binding domain, KBTBD7 activates transcription; deletion analysis shows the BTB domain and kelch repeat motif are the main regions for transcriptional activation. Overexpression in MCF-7 cells activates AP-1 and SRE transcriptional activities, an effect reversed by siRNA knockdown.\",\n      \"method\": \"Western blot (expression/localization), GAL4-fusion transcription assay, deletion constructs, AP-1/SRE luciferase reporter assays, siRNA knockdown\",\n      \"journal\": \"BMB reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — multiple reporter assays and domain deletion analysis, single lab, no endogenous protein functional validation\",\n      \"pmids\": [\"20132730\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KBTBD7 is a BTB-kelch domain-containing substrate adaptor for CUL3 RING ubiquitin ligase complexes that targets multiple substrates—including TIAM1, Vangl1/2, DRD2, PTEN, and KLF15—for ubiquitination and proteasomal degradation; through TIAM1 degradation it spatially restricts RAC1 signaling at GABARAP-containing vesicles, through Vangl degradation it controls Wnt/PCP signaling and convergent extension, and through interaction with MKK3/6 it promotes p38 and NF-κB inflammatory signaling downstream of DAMPs.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KBTBD7 is a BTB-kelch substrate adaptor that confers target specificity on CUL3 RING ubiquitin ligase complexes, directing multiple substrates to ubiquitin-dependent proteasomal degradation [#0]. Acting with its paralog KBTBD6, it ubiquitylates the RAC1-specific GEF TIAM1; loss of KBTBD7 stabilizes TIAM1, elevates RAC1 activity, remodels actin, and enhances invasion, and its preferential binding to GABARAP via ATG8-interacting motifs spatially restricts this RAC1 signaling to GABARAP-containing vesicles [#0]. In the Wnt/PCP pathway, KBTBD7 is recruited by p97/VCP through UBA-UBX adaptors to ubiquitinate the core components Vangl1 and Vangl2 for ER-associated degradation, a step blocked by Wnt5a/CK1-induced Vangl phosphorylation, and it regulates convergent extension during zebrafish gastrulation [#1]. It additionally targets internalized DRD2 at five mapped lysines, controlling DRD2 abundance in vivo and modulating AKT/mTOR responses to dopamine agonists [#2], and degrades PTEN to activate EGFR/PI3K/AKT signaling in lung cancer cells [#4]. Independently of its adaptor function, KBTBD7 physically interacts with MKK3/6 to promote p38 and NF-\\u03baB inflammatory signaling downstream of DAMPs, and it is a direct target of miR-21 [#3]; it also drives inflammatory programs through ubiquitination of the transcription factor KLF15 [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Initial characterization established KBTBD7 as a cytoplasmic BTB-kelch protein capable of modulating transcriptional output, the first functional readout for an otherwise uncharacterized gene.\",\n      \"evidence\": \"Western blot localization, GAL4-fusion and AP-1/SRE luciferase reporter assays with domain deletions and siRNA in COS-7/MCF-7 cells\",\n      \"pmids\": [\"20132730\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Transcriptional activation measured only via artificial GAL4 fusion and reporter overexpression, not endogenous targets\",\n        \"No molecular mechanism connecting KBTBD7 to AP-1/SRE established\",\n        \"No ubiquitin ligase or substrate-adaptor role yet identified\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined KBTBD7's core molecular identity as a CUL3 substrate adaptor that ubiquitylates TIAM1, resolving how it functions biochemically and linking it to spatial control of RAC1 signaling via GABARAP vesicles.\",\n      \"evidence\": \"Reciprocal Co-IP, ubiquitylation assays, siRNA with actin/invasion/proliferation readouts, ATG8-binding motif mutagenesis and vesicle recruitment assays\",\n      \"pmids\": [\"25684205\", \"27308540\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Generality of GABARAP-dependent recruitment to other substrates not tested\",\n        \"Relative contributions of KBTBD6 versus KBTBD7 not fully dissected\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended the substrate repertoire to DRD2 with residue-level resolution and in vivo validation, showing KBTBD7 controls receptor abundance and downstream AKT/mTOR signaling.\",\n      \"evidence\": \"Yeast two-hybrid, Co-IP, ubiquitination site mapping (K221/226/241/251/258), CRISPR KO mice, cell-based signaling readouts\",\n      \"pmids\": [\"32572597\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether DRD2 ubiquitination uses the same CUL3 complex as TIAM1 not directly shown\",\n        \"Tissue-specific determinants of substrate selection unclear\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected KBTBD7 to ERAD and Wnt/PCP by showing p97/VCP-mediated recruitment drives Vangl1/2 degradation, establishing a phospho-regulated quality-control step controlling planar cell polarity in vivo.\",\n      \"evidence\": \"Co-IP (p97/VCP\\u2013KBTBD7, KBTBD7\\u2013Vangl), ubiquitination and ERAD assays, phospho-blocking mutants, zebrafish convergent-extension loss/rescue\",\n      \"pmids\": [\"33990333\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"How VCP-UBX recruitment relates to CUL3 adaptor function not reconciled\",\n        \"Structural basis of phospho-dependent escape from ubiquitination not resolved\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Revealed a non-degradative signaling role: KBTBD7 binds and activates MKK3/6 to amplify DAMP-triggered p38/NF-\\u03baB inflammation, and is itself repressed by miR-21.\",\n      \"evidence\": \"Luciferase 3'UTR reporter, Co-IP (KBTBD7\\u2013MKK3/6), miR-21 KO mice, siRNA with cytokine/phospho-signaling readouts post-MI\",\n      \"pmids\": [\"29991775\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether MKK3/6 activation requires ubiquitin ligase activity or is adaptor-independent unclear\",\n        \"Single Co-IP for the KBTBD7\\u2013MKK3/6 interaction without structural mapping\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Added PTEN as a degradation substrate, positioning KBTBD7 as a driver of EGFR/PI3K/AKT signaling in lung cancer.\",\n      \"evidence\": \"Knockdown in NSCLC lines with PTEN level, ubiquitination assays, AKT/proliferation/invasion readouts\",\n      \"pmids\": [\"35499228\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"CUL3 dependence of PTEN ubiquitination not demonstrated\",\n        \"Single-lab, single-study evidence\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Implicated KBTBD7 in inflammatory regulation through ubiquitination of KLF15 and an interaction with FOXA1, linking it to NLRP3/NF-\\u03baB signaling and ferroptosis in injury models.\",\n      \"evidence\": \"Co-IP (KBTBD7\\u2013KLF15, KBTBD7\\u2013FOXA1), ubiquitination assays, siRNA with NLRP3/NF-\\u03baB and ferroptosis/ROS readouts, epistasis rescue, sepsis/lung injury mouse models\",\n      \"pmids\": [\"39489209\", \"38652964\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"FOXA1\\u2013SLC7A11 link inferred indirectly (idx 6 is Low confidence)\",\n        \"How KBTBD7 both degrades a transcription factor and stabilizes another (FOXA1) is mechanistically unreconciled\",\n        \"CUL3 dependence not established for KLF15\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how KBTBD7 selects among its diverse substrates and whether its non-degradative kinase-activating and transcriptional roles share a common structural mechanism.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No structural model of substrate or CUL3/VCP engagement\",\n        \"Substrate-selection determinants across tissues uncharacterized\",\n        \"Reconciliation of CUL3-adaptor versus VCP-recruited versus MKK3/6-activating activities unresolved\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 2, 4, 5]},\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [1, 5]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"complexes\": [\n      \"CUL3-RING ubiquitin ligase complex\"\n    ],\n    \"partners\": [\n      \"TIAM1\",\n      \"GABARAP\",\n      \"Vangl1\",\n      \"Vangl2\",\n      \"VCP\",\n      \"DRD2\",\n      \"MKK3/6\",\n      \"KLF15\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}