{"gene":"DCAF12","run_date":"2026-04-28T17:28:53","timeline":{"discoveries":[{"year":2019,"finding":"CRL4-DCAF12 E3 ubiquitin ligase targets MAGE-A3/6 for proteasomal degradation in response to nutrient deprivation, and this degradation is required for starvation-induced autophagy. Proteomic analysis identified DCAF12 as the substrate receptor mediating MAGE-A3/6 ubiquitination.","method":"Proteomic/mass spectrometry interactome, proteasome inhibitor rescue, starvation assays, loss-of-function with autophagy readout","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 — reciprocal proteomics + functional epistasis with defined cellular phenotype (autophagy), replicated across conditions","pmids":["31267705"],"is_preprint":false},{"year":2021,"finding":"CRL4-DCAF12 ubiquitin ligase recognizes a C-terminal acidic degron and promotes proteasomal degradation of MOV10, an RNA helicase/RISC component. DCAF12 knockout mice show elevated MOV10 levels in testes (with impaired spermatogenesis) and in activated T cells (with increased caspase activation), establishing MOV10 as a physiological substrate of DCAF12.","method":"CRL4-DCAF12 complex purification, Dcaf12 knockout mice, C-terminal degron mutant analysis, proteasome inhibitor rescue, flow cytometry, meiotic marker analysis","journal":"International journal of molecular sciences","confidence":"High","confidence_rationale":"Tier 2 — genetic KO in mice with multiple orthogonal readouts (sperm count, meiotic markers, caspase activation) plus biochemical substrate validation","pmids":["34065512"],"is_preprint":false},{"year":2019,"finding":"Drosophila DCAF12 (ortholog of human DCAF12) acts presynaptically to promote evoked neurotransmitter release and is required for homeostatic synaptic potentiation at the NMJ; postsynaptically, it negatively regulates glutamate receptor subunit levels (GluRIIA, GluRIIC, GluRIID) via a Cul4-dependent ubiquitination mechanism in muscle nuclei.","method":"Genetic deletion in Drosophila, electrophysiology, immunofluorescence, genetic epistasis with Cul4","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — Drosophila ortholog with multiple independent genetic and electrophysiological readouts establishing pathway position","pmids":["30670470"],"is_preprint":false},{"year":2016,"finding":"Drosophila DCAF12 is required for Diap1 cleavage in response to pro-apoptotic signals and is necessary and sufficient for RHG (Reaper, Hid, Grim)-mediated apoptosis; loss of DCAF12 enhances tumor growth caused by loss of neoplastic tumor suppressors.","method":"Drosophila genetic loss-of-function, apoptosis assays, epistasis with pro-apoptotic and tumor suppressor pathways","journal":"Developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis in Drosophila ortholog; single lab, no biochemical reconstitution of DCAF12-Diap1 interaction","pmids":["26972874"],"is_preprint":false},{"year":2022,"finding":"Human DCAF12 binds multiple IAP family members (XIAP, cIAP1, cIAP2, BRUCE) through their BIR domains; upon apoptotic stimuli, DCAF12 translocates from nucleus to cytoplasm and blocks XIAP-caspase interaction to facilitate caspase activation and apoptosis, and similarly suppresses NF-κB activation in an IAP-binding-dependent manner.","method":"Co-immunoprecipitation, subcellular fractionation/localization, caspase activation assays, NF-κB reporter assays, domain mapping, loss-of-function","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP for multiple IAPs plus functional rescue experiments; single lab","pmids":["35459779"],"is_preprint":false},{"year":2023,"finding":"Cryo-EM structure of the DDB1-DCAF12-CCT5 complex at 2.8 Å resolution shows DCAF12 acts as a canonical WD40 substrate receptor using a positively charged pocket at the center of its β-propeller to bind the C-terminal di-Glu degron of CCT5; DCAF12 ubiquitinates monomeric CCT5 but not CCT5 assembled into the TRiC complex, establishing CRL4DCAF12 as an Assembly Quality Control E3 ligase.","method":"Cryo-EM structure determination, in vitro ubiquitination assays, mutagenesis, biochemical binding assays","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 — cryo-EM structure at 2.8 Å with mutagenesis and in vitro ubiquitination functional validation","pmids":["36715408"],"is_preprint":false},{"year":2024,"finding":"Cryo-EM structure of DDB1-DCAF12-MAGEA3 complex at 3.17 Å reveals key DCAF12 residues responsible for C-terminal di-Glu degron recognition; NanoBRET and biophysical assays demonstrate nanomolar affinity interactions between DCAF12 and C-terminal degron peptides of both MAGEA3 and CCT5 in vitro and in cells.","method":"Cryo-EM structure determination, NanoBRET proximity assay, biophysical binding assays (ITC/SPR), degron peptide mutagenesis","journal":"PNAS nexus","confidence":"High","confidence_rationale":"Tier 1 — cryo-EM structure complemented by multiple orthogonal biophysical and cellular binding assays","pmids":["38665159"],"is_preprint":false},{"year":2025,"finding":"CRL4DCAF12 promotes degradation of MCMBP (MCM-binding protein), which facilitates removal of MCMBP from MCM3-7 subcomplexes in the nucleus to allow MCM2 incorporation and assembly of the full MCM2-7 replicative helicase. Loss of DCAF12 stabilizes MCMBP, reduces chromatin-bound nascent MCM levels, causes accelerated replication forks, and induces replication stress.","method":"Genetic knockdown/knockout, co-immunoprecipitation, protein stability/degradation assays, DNA fiber assay, chromatin fractionation, replication stress markers","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (biochemistry, chromatin fractionation, DNA fiber analysis) establishing pathway position; published in peer-reviewed journal","pmids":["41145411"],"is_preprint":false},{"year":2025,"finding":"DCAF12 catalyzes non-degradative ubiquitination of TRiC/CCT subunits to enhance chaperonin assembly and folding of cytoskeletal effectors (β-actin, tubulin) and oncogenic clients (STAT3, Raptor, mLST8), thereby activating YAP, STAT3, and mTOR pathways to promote lung cancer metastasis.","method":"DCAF12 genetic knockdown, in vitro ubiquitination assays, proteomics, xenograft/metastasis in vivo models, pharmacological inhibition (HSF1A)","journal":"Advanced science","confidence":"Medium","confidence_rationale":"Tier 2 — in vitro ubiquitination and multiple pathway readouts in a single study; non-degradative ubiquitination mechanism requires further independent validation","pmids":["41047465"],"is_preprint":false}],"current_model":"DCAF12 functions as the substrate receptor subunit of the CUL4-RBX1-DDB1-DCAF12 (CRL4DCAF12) E3 ubiquitin ligase complex, recognizing C-terminal di-glutamate degrons in substrates such as CCT5, MAGE-A3/6, MOV10, and MCMBP to promote their proteasomal degradation or non-degradative ubiquitination, thereby controlling Assembly Quality Control of protein complexes (TRiC/CCT, MCM2-7), starvation-induced autophagy, DNA replication licensing, spermatogenesis, T cell activation, and apoptosis through IAP antagonism."},"narrative":{"teleology":[{"year":2016,"claim":"Whether DCAF12 had a biological role beyond being a DDB1-associated factor was unknown; genetic studies in Drosophila established that DCAF12 is necessary and sufficient for RHG-mediated apoptosis through Diap1 cleavage, linking it to IAP antagonism and tumor suppression.","evidence":"Drosophila loss-of-function genetics with apoptosis and tumor suppressor epistasis","pmids":["26972874"],"confidence":"Medium","gaps":["No biochemical reconstitution of DCAF12–Diap1 interaction","Mechanism of Diap1 cleavage promotion not resolved","Not confirmed in mammalian system at this stage"]},{"year":2019,"claim":"Two studies simultaneously revealed CRL4^DCAF12's substrate-targeting and synaptic roles: proteomic identification showed DCAF12 recruits MAGE-A3/6 for proteasomal degradation to enable starvation-induced autophagy, while Drosophila studies demonstrated presynaptic regulation of neurotransmitter release and postsynaptic Cul4-dependent ubiquitination of glutamate receptors.","evidence":"Proteomic interactome with proteasome inhibitor rescue and autophagy assays in human cells; Drosophila electrophysiology and genetic epistasis with Cul4","pmids":["31267705","30670470"],"confidence":"High","gaps":["Degron motif on MAGE-A3/6 not yet identified","Glutamate receptor substrates not shown to be direct DCAF12 substrates biochemically","No structural insight into substrate recognition"]},{"year":2021,"claim":"The physiological importance of DCAF12 in mammals was established by knockout mice, revealing MOV10 as a C-terminal acidic degron-bearing substrate whose stabilization causes impaired spermatogenesis and aberrant caspase activation in T cells.","evidence":"Dcaf12 knockout mice with sperm counts, meiotic markers, flow cytometry for caspase activation, and degron mutant analysis","pmids":["34065512"],"confidence":"High","gaps":["Precise degron sequence on MOV10 not structurally resolved","Whether spermatogenesis defect is MOV10-dependent or involves additional substrates unclear","Mechanism linking MOV10 to caspase activation in T cells not fully dissected"]},{"year":2022,"claim":"The apoptotic function of DCAF12 was extended to human cells by demonstrating that DCAF12 translocates from nucleus to cytoplasm upon apoptotic stimuli and directly binds BIR domains of multiple IAPs (XIAP, cIAP1, cIAP2, BRUCE) to block caspase inhibition and suppress NF-κB signaling.","evidence":"Reciprocal co-immunoprecipitation, subcellular fractionation, caspase and NF-κB reporter assays with domain mapping","pmids":["35459779"],"confidence":"Medium","gaps":["Single lab study; independent replication needed","Whether IAP binding is independent of or coupled to CRL4 ligase activity not resolved","In vivo relevance of nuclear-to-cytoplasmic translocation not tested in animal models"]},{"year":2023,"claim":"The structural basis for substrate recognition was resolved: a 2.8 Å cryo-EM structure of DDB1–DCAF12–CCT5 showed that DCAF12's WD40 β-propeller uses a central positively charged pocket to capture the C-terminal di-Glu degron, and DCAF12 ubiquitinates only monomeric CCT5, not TRiC-assembled CCT5, establishing the Assembly Quality Control paradigm.","evidence":"Cryo-EM at 2.8 Å, mutagenesis of degron-binding pocket, in vitro ubiquitination comparing monomeric vs. assembled CCT5","pmids":["36715408"],"confidence":"High","gaps":["How assembly state is sensed (steric occlusion vs. allosteric mechanism) not fully elucidated","Scope of the di-Glu degron proteome not systematically defined","No in vivo validation of assembly quality control function at this stage"]},{"year":2024,"claim":"A second cryo-EM structure (DDB1–DCAF12–MAGEA3 at 3.17 Å) confirmed the generality of di-Glu degron recognition and biophysical assays demonstrated nanomolar affinity, validating the degron-binding pocket as a conserved substrate recruitment mechanism.","evidence":"Cryo-EM structure, NanoBRET, ITC/SPR with degron peptide mutagenesis","pmids":["38665159"],"confidence":"High","gaps":["Whether DCAF12 recognizes non-di-Glu acidic degrons remains untested","Structural basis for IAP (BIR domain) binding by DCAF12 not resolved","Therapeutic tractability of the degron pocket not explored"]},{"year":2025,"claim":"Two studies extended DCAF12 substrate repertoire and functional impact: CRL4^DCAF12 degrades MCMBP to enable MCM2-7 helicase assembly and proper replication licensing, and separately catalyzes non-degradative ubiquitination of TRiC subunits to enhance chaperonin activity and promote oncogenic signaling (YAP, STAT3, mTOR) in lung cancer metastasis.","evidence":"Genetic knockdown/knockout with chromatin fractionation and DNA fiber assays (MCMBP); in vitro ubiquitination, proteomics, and xenograft metastasis models (TRiC)","pmids":["41145411","41047465"],"confidence":"High","gaps":["Non-degradative ubiquitination of TRiC requires independent validation","Whether MCMBP degradation also involves di-Glu degron recognition not structurally confirmed","Relative contributions of degradative vs. non-degradative ubiquitination to TRiC regulation unclear"]},{"year":null,"claim":"Key open questions include the full scope of the di-Glu degron proteome, the structural basis for DCAF12's IAP/BIR-domain interaction, whether assembly quality control extends to additional multisubunit complexes beyond TRiC and MCM2-7, and whether DCAF12's ligase-dependent and ligase-independent (IAP-antagonist) functions are coordinated.","evidence":"","pmids":[],"confidence":"Low","gaps":["Systematic identification of all C-terminal di-Glu degron substrates not performed","No structure of DCAF12 bound to any IAP BIR domain","Relationship between CRL4 ligase activity and IAP-antagonist function unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,5,7,8]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4,7]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[4,8]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,1,5,7,8]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3,4]},{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[7]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,8]}],"complexes":["CRL4^DCAF12 (CUL4-RBX1-DDB1-DCAF12)"],"partners":["DDB1","CUL4A","CCT5","MAGE-A3","MOV10","MCMBP","XIAP","CIAP1"],"other_free_text":[]},"mechanistic_narrative":"DCAF12 is the substrate receptor of the CRL4^DCAF12 E3 ubiquitin ligase complex, recognizing C-terminal di-glutamate degrons on substrates to direct their ubiquitination for proteasomal degradation or non-degradative modification. Cryo-EM structures of DDB1–DCAF12 bound to CCT5 and MAGE-A3 reveal a positively charged pocket at the center of its WD40 β-propeller that captures the di-Glu degron with nanomolar affinity, and DCAF12 selectively ubiquitinates unassembled monomeric subunits (e.g., CCT5, MCMBP) rather than their fully assembled complexes (TRiC, MCM2-7), establishing it as a key Assembly Quality Control ligase that also controls starvation-induced autophagy via MAGE-A3/6 degradation, DNA replication licensing via MCMBP turnover, spermatogenesis, and T cell homeostasis via MOV10 degradation [PMID:36715408, PMID:38665159, PMID:31267705, PMID:34065512, PMID:41145411]. DCAF12 also promotes apoptosis independently of its degron-recognition function by binding IAP family members (XIAP, cIAP1, cIAP2) through their BIR domains and antagonizing their caspase-inhibitory activity, a role conserved in Drosophila where DCAF12 is required for RHG-mediated apoptosis and Diap1 cleavage [PMID:35459779, PMID:26972874]. Additionally, CRL4^DCAF12 catalyzes non-degradative ubiquitination of TRiC/CCT subunits to enhance chaperonin-assisted folding of cytoskeletal and signaling clients, promoting YAP, STAT3, and mTOR pathway activation in cancer contexts [PMID:41047465]."},"prefetch_data":{"uniprot":{"accession":"Q5T6F0","full_name":"DDB1- and CUL4-associated factor 12","aliases":["Centrosome-related protein TCC52","Testis cancer centrosome-related protein","WD repeat-containing protein 40A"],"length_aa":453,"mass_kda":50.5,"function":"Substrate-recognition component of a DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complex of the DesCEND (destruction via C-end degrons) pathway, which recognizes a C-degron located at the extreme C terminus of target proteins, leading to their ubiquitination and degradation (PubMed:16949367, PubMed:16964240, PubMed:29779948). The C-degron recognized by the DesCEND pathway is usually a motif of less than ten residues and can be present in full-length proteins, truncated proteins or proteolytically cleaved forms (PubMed:29779948). The DCX(DCAF12) complex specifically recognizes proteins with a diglutamate (Glu-Glu) at the C-terminus, such as MAGEA3, MAGEA6 and CCT5, leading to their ubiquitination and degradation (PubMed:29779948, PubMed:31267705). Ubiquitination of MAGEA3, MAGEA6 by DCX(DCAF12) complex is required for starvation-induced autophagy (PubMed:31267705). Also directly recognizes the C-terminal glutamate-leucine (Glu-Leu) degron as an alternative degron in proteins such as MOV10, leading to their ubiquitination and degradation. Controls the protein level of MOV10 during spermatogenesis and in T cells, especially after their activation (PubMed:34065512)","subcellular_location":"Cytoplasm; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q5T6F0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DCAF12","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DDB1","stoichiometry":0.2},{"gene":"VPS35","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/DCAF12","total_profiled":1310},"omim":[{"mim_id":"620087","title":"DDB1- AND CUL4-ASSOCIATED FACTOR 12; DCAF12","url":"https://www.omim.org/entry/620087"}],"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/DCAF12"},"hgnc":{"alias_symbol":["DKFZP434O125","MGC1058","CT102","TCC52"],"prev_symbol":["KIAA1892","WDR40A"]},"alphafold":{"accession":"Q5T6F0","domains":[{"cath_id":"2.130.10.10","chopping":"81-377_385-451","consensus_level":"high","plddt":91.8516,"start":81,"end":451}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5T6F0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q5T6F0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q5T6F0-F1-predicted_aligned_error_v6.png","plddt_mean":84.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DCAF12","jax_strain_url":"https://www.jax.org/strain/search?query=DCAF12"},"sequence":{"accession":"Q5T6F0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q5T6F0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q5T6F0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5T6F0"}},"corpus_meta":[{"pmid":"21325547","id":"PMC_21325547","title":"Evaluation of a DNA microarray (Check-MDR CT102) for rapid detection of TEM, SHV, and CTX-M extended-spectrum β-lactamases and of KPC, OXA-48, VIM, IMP, and NDM-1 carbapenemases.","date":"2011","source":"Journal of clinical microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/21325547","citation_count":101,"is_preprint":false},{"pmid":"31267705","id":"PMC_31267705","title":"Regulation of MAGE-A3/6 by the CRL4-DCAF12 ubiquitin ligase and nutrient availability.","date":"2019","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/31267705","citation_count":38,"is_preprint":false},{"pmid":"34065512","id":"PMC_34065512","title":"CRL4-DCAF12 Ubiquitin Ligase Controls MOV10 RNA Helicase during Spermatogenesis and T Cell Activation.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34065512","citation_count":21,"is_preprint":false},{"pmid":"30670470","id":"PMC_30670470","title":"Cul4 ubiquitin ligase cofactor DCAF12 promotes neurotransmitter release and homeostatic plasticity.","date":"2019","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/30670470","citation_count":19,"is_preprint":false},{"pmid":"36715408","id":"PMC_36715408","title":"Recognition of the CCT5 di-Glu degron by CRL4DCAF12 is dependent on TRiC assembly.","date":"2023","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/36715408","citation_count":18,"is_preprint":false},{"pmid":"26972874","id":"PMC_26972874","title":"Control of apoptosis by Drosophila DCAF12.","date":"2016","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/26972874","citation_count":18,"is_preprint":false},{"pmid":"35508302","id":"PMC_35508302","title":"Activity and Tissue Distribution of Antisense Oligonucleotide CT102 Encapsulated with Cytidinyl/Cationic Lipid against Hepatocellular Carcinoma.","date":"2022","source":"Molecular 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Myasthenia Gravis.","date":"2022","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/35655486","citation_count":4,"is_preprint":false},{"pmid":"41047465","id":"PMC_41047465","title":"DCAF12 Ubiquitin Ligase Promotes Lung Cancer Metastasis by Modulating the TRiC/CCT Chaperonin Complex.","date":"2025","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/41047465","citation_count":2,"is_preprint":false},{"pmid":"41145411","id":"PMC_41145411","title":"CRL4DCAF12 regulation of MCMBP ensures optimal licensing of DNA replication.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/41145411","citation_count":1,"is_preprint":false},{"pmid":"41175836","id":"PMC_41175836","title":"Anti-IGF-1R antisense oligonucleotide CT102: A promising therapeutic agent for graves' ophthalmopathy.","date":"2025","source":"The Journal of pharmacology and experimental 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starvation-induced autophagy. Proteomic analysis identified DCAF12 as the substrate receptor mediating MAGE-A3/6 ubiquitination.\",\n      \"method\": \"Proteomic/mass spectrometry interactome, proteasome inhibitor rescue, starvation assays, loss-of-function with autophagy readout\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal proteomics + functional epistasis with defined cellular phenotype (autophagy), replicated across conditions\",\n      \"pmids\": [\"31267705\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CRL4-DCAF12 ubiquitin ligase recognizes a C-terminal acidic degron and promotes proteasomal degradation of MOV10, an RNA helicase/RISC component. DCAF12 knockout mice show elevated MOV10 levels in testes (with impaired spermatogenesis) and in activated T cells (with increased caspase activation), establishing MOV10 as a physiological substrate of DCAF12.\",\n      \"method\": \"CRL4-DCAF12 complex purification, Dcaf12 knockout mice, C-terminal degron mutant analysis, proteasome inhibitor rescue, flow cytometry, meiotic marker analysis\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO in mice with multiple orthogonal readouts (sperm count, meiotic markers, caspase activation) plus biochemical substrate validation\",\n      \"pmids\": [\"34065512\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Drosophila DCAF12 (ortholog of human DCAF12) acts presynaptically to promote evoked neurotransmitter release and is required for homeostatic synaptic potentiation at the NMJ; postsynaptically, it negatively regulates glutamate receptor subunit levels (GluRIIA, GluRIIC, GluRIID) via a Cul4-dependent ubiquitination mechanism in muscle nuclei.\",\n      \"method\": \"Genetic deletion in Drosophila, electrophysiology, immunofluorescence, genetic epistasis with Cul4\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Drosophila ortholog with multiple independent genetic and electrophysiological readouts establishing pathway position\",\n      \"pmids\": [\"30670470\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Drosophila DCAF12 is required for Diap1 cleavage in response to pro-apoptotic signals and is necessary and sufficient for RHG (Reaper, Hid, Grim)-mediated apoptosis; loss of DCAF12 enhances tumor growth caused by loss of neoplastic tumor suppressors.\",\n      \"method\": \"Drosophila genetic loss-of-function, apoptosis assays, epistasis with pro-apoptotic and tumor suppressor pathways\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis in Drosophila ortholog; single lab, no biochemical reconstitution of DCAF12-Diap1 interaction\",\n      \"pmids\": [\"26972874\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Human DCAF12 binds multiple IAP family members (XIAP, cIAP1, cIAP2, BRUCE) through their BIR domains; upon apoptotic stimuli, DCAF12 translocates from nucleus to cytoplasm and blocks XIAP-caspase interaction to facilitate caspase activation and apoptosis, and similarly suppresses NF-κB activation in an IAP-binding-dependent manner.\",\n      \"method\": \"Co-immunoprecipitation, subcellular fractionation/localization, caspase activation assays, NF-κB reporter assays, domain mapping, loss-of-function\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP for multiple IAPs plus functional rescue experiments; single lab\",\n      \"pmids\": [\"35459779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Cryo-EM structure of the DDB1-DCAF12-CCT5 complex at 2.8 Å resolution shows DCAF12 acts as a canonical WD40 substrate receptor using a positively charged pocket at the center of its β-propeller to bind the C-terminal di-Glu degron of CCT5; DCAF12 ubiquitinates monomeric CCT5 but not CCT5 assembled into the TRiC complex, establishing CRL4DCAF12 as an Assembly Quality Control E3 ligase.\",\n      \"method\": \"Cryo-EM structure determination, in vitro ubiquitination assays, mutagenesis, biochemical binding assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — cryo-EM structure at 2.8 Å with mutagenesis and in vitro ubiquitination functional validation\",\n      \"pmids\": [\"36715408\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Cryo-EM structure of DDB1-DCAF12-MAGEA3 complex at 3.17 Å reveals key DCAF12 residues responsible for C-terminal di-Glu degron recognition; NanoBRET and biophysical assays demonstrate nanomolar affinity interactions between DCAF12 and C-terminal degron peptides of both MAGEA3 and CCT5 in vitro and in cells.\",\n      \"method\": \"Cryo-EM structure determination, NanoBRET proximity assay, biophysical binding assays (ITC/SPR), degron peptide mutagenesis\",\n      \"journal\": \"PNAS nexus\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — cryo-EM structure complemented by multiple orthogonal biophysical and cellular binding assays\",\n      \"pmids\": [\"38665159\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CRL4DCAF12 promotes degradation of MCMBP (MCM-binding protein), which facilitates removal of MCMBP from MCM3-7 subcomplexes in the nucleus to allow MCM2 incorporation and assembly of the full MCM2-7 replicative helicase. Loss of DCAF12 stabilizes MCMBP, reduces chromatin-bound nascent MCM levels, causes accelerated replication forks, and induces replication stress.\",\n      \"method\": \"Genetic knockdown/knockout, co-immunoprecipitation, protein stability/degradation assays, DNA fiber assay, chromatin fractionation, replication stress markers\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (biochemistry, chromatin fractionation, DNA fiber analysis) establishing pathway position; published in peer-reviewed journal\",\n      \"pmids\": [\"41145411\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"DCAF12 catalyzes non-degradative ubiquitination of TRiC/CCT subunits to enhance chaperonin assembly and folding of cytoskeletal effectors (β-actin, tubulin) and oncogenic clients (STAT3, Raptor, mLST8), thereby activating YAP, STAT3, and mTOR pathways to promote lung cancer metastasis.\",\n      \"method\": \"DCAF12 genetic knockdown, in vitro ubiquitination assays, proteomics, xenograft/metastasis in vivo models, pharmacological inhibition (HSF1A)\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro ubiquitination and multiple pathway readouts in a single study; non-degradative ubiquitination mechanism requires further independent validation\",\n      \"pmids\": [\"41047465\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DCAF12 functions as the substrate receptor subunit of the CUL4-RBX1-DDB1-DCAF12 (CRL4DCAF12) E3 ubiquitin ligase complex, recognizing C-terminal di-glutamate degrons in substrates such as CCT5, MAGE-A3/6, MOV10, and MCMBP to promote their proteasomal degradation or non-degradative ubiquitination, thereby controlling Assembly Quality Control of protein complexes (TRiC/CCT, MCM2-7), starvation-induced autophagy, DNA replication licensing, spermatogenesis, T cell activation, and apoptosis through IAP antagonism.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"DCAF12 is the substrate receptor of the CRL4^DCAF12 E3 ubiquitin ligase complex, recognizing C-terminal di-glutamate degrons on substrates to direct their ubiquitination for proteasomal degradation or non-degradative modification. Cryo-EM structures of DDB1–DCAF12 bound to CCT5 and MAGE-A3 reveal a positively charged pocket at the center of its WD40 β-propeller that captures the di-Glu degron with nanomolar affinity, and DCAF12 selectively ubiquitinates unassembled monomeric subunits (e.g., CCT5, MCMBP) rather than their fully assembled complexes (TRiC, MCM2-7), establishing it as a key Assembly Quality Control ligase that also controls starvation-induced autophagy via MAGE-A3/6 degradation, DNA replication licensing via MCMBP turnover, spermatogenesis, and T cell homeostasis via MOV10 degradation [PMID:36715408, PMID:38665159, PMID:31267705, PMID:34065512, PMID:41145411]. DCAF12 also promotes apoptosis independently of its degron-recognition function by binding IAP family members (XIAP, cIAP1, cIAP2) through their BIR domains and antagonizing their caspase-inhibitory activity, a role conserved in Drosophila where DCAF12 is required for RHG-mediated apoptosis and Diap1 cleavage [PMID:35459779, PMID:26972874]. Additionally, CRL4^DCAF12 catalyzes non-degradative ubiquitination of TRiC/CCT subunits to enhance chaperonin-assisted folding of cytoskeletal and signaling clients, promoting YAP, STAT3, and mTOR pathway activation in cancer contexts [PMID:41047465].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Whether DCAF12 had a biological role beyond being a DDB1-associated factor was unknown; genetic studies in Drosophila established that DCAF12 is necessary and sufficient for RHG-mediated apoptosis through Diap1 cleavage, linking it to IAP antagonism and tumor suppression.\",\n      \"evidence\": \"Drosophila loss-of-function genetics with apoptosis and tumor suppressor epistasis\",\n      \"pmids\": [\"26972874\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No biochemical reconstitution of DCAF12–Diap1 interaction\",\n        \"Mechanism of Diap1 cleavage promotion not resolved\",\n        \"Not confirmed in mammalian system at this stage\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Two studies simultaneously revealed CRL4^DCAF12's substrate-targeting and synaptic roles: proteomic identification showed DCAF12 recruits MAGE-A3/6 for proteasomal degradation to enable starvation-induced autophagy, while Drosophila studies demonstrated presynaptic regulation of neurotransmitter release and postsynaptic Cul4-dependent ubiquitination of glutamate receptors.\",\n      \"evidence\": \"Proteomic interactome with proteasome inhibitor rescue and autophagy assays in human cells; Drosophila electrophysiology and genetic epistasis with Cul4\",\n      \"pmids\": [\"31267705\", \"30670470\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Degron motif on MAGE-A3/6 not yet identified\",\n        \"Glutamate receptor substrates not shown to be direct DCAF12 substrates biochemically\",\n        \"No structural insight into substrate recognition\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The physiological importance of DCAF12 in mammals was established by knockout mice, revealing MOV10 as a C-terminal acidic degron-bearing substrate whose stabilization causes impaired spermatogenesis and aberrant caspase activation in T cells.\",\n      \"evidence\": \"Dcaf12 knockout mice with sperm counts, meiotic markers, flow cytometry for caspase activation, and degron mutant analysis\",\n      \"pmids\": [\"34065512\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Precise degron sequence on MOV10 not structurally resolved\",\n        \"Whether spermatogenesis defect is MOV10-dependent or involves additional substrates unclear\",\n        \"Mechanism linking MOV10 to caspase activation in T cells not fully dissected\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"The apoptotic function of DCAF12 was extended to human cells by demonstrating that DCAF12 translocates from nucleus to cytoplasm upon apoptotic stimuli and directly binds BIR domains of multiple IAPs (XIAP, cIAP1, cIAP2, BRUCE) to block caspase inhibition and suppress NF-κB signaling.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, subcellular fractionation, caspase and NF-κB reporter assays with domain mapping\",\n      \"pmids\": [\"35459779\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single lab study; independent replication needed\",\n        \"Whether IAP binding is independent of or coupled to CRL4 ligase activity not resolved\",\n        \"In vivo relevance of nuclear-to-cytoplasmic translocation not tested in animal models\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"The structural basis for substrate recognition was resolved: a 2.8 Å cryo-EM structure of DDB1–DCAF12–CCT5 showed that DCAF12's WD40 β-propeller uses a central positively charged pocket to capture the C-terminal di-Glu degron, and DCAF12 ubiquitinates only monomeric CCT5, not TRiC-assembled CCT5, establishing the Assembly Quality Control paradigm.\",\n      \"evidence\": \"Cryo-EM at 2.8 Å, mutagenesis of degron-binding pocket, in vitro ubiquitination comparing monomeric vs. assembled CCT5\",\n      \"pmids\": [\"36715408\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"How assembly state is sensed (steric occlusion vs. allosteric mechanism) not fully elucidated\",\n        \"Scope of the di-Glu degron proteome not systematically defined\",\n        \"No in vivo validation of assembly quality control function at this stage\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A second cryo-EM structure (DDB1–DCAF12–MAGEA3 at 3.17 Å) confirmed the generality of di-Glu degron recognition and biophysical assays demonstrated nanomolar affinity, validating the degron-binding pocket as a conserved substrate recruitment mechanism.\",\n      \"evidence\": \"Cryo-EM structure, NanoBRET, ITC/SPR with degron peptide mutagenesis\",\n      \"pmids\": [\"38665159\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether DCAF12 recognizes non-di-Glu acidic degrons remains untested\",\n        \"Structural basis for IAP (BIR domain) binding by DCAF12 not resolved\",\n        \"Therapeutic tractability of the degron pocket not explored\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Two studies extended DCAF12 substrate repertoire and functional impact: CRL4^DCAF12 degrades MCMBP to enable MCM2-7 helicase assembly and proper replication licensing, and separately catalyzes non-degradative ubiquitination of TRiC subunits to enhance chaperonin activity and promote oncogenic signaling (YAP, STAT3, mTOR) in lung cancer metastasis.\",\n      \"evidence\": \"Genetic knockdown/knockout with chromatin fractionation and DNA fiber assays (MCMBP); in vitro ubiquitination, proteomics, and xenograft metastasis models (TRiC)\",\n      \"pmids\": [\"41145411\", \"41047465\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Non-degradative ubiquitination of TRiC requires independent validation\",\n        \"Whether MCMBP degradation also involves di-Glu degron recognition not structurally confirmed\",\n        \"Relative contributions of degradative vs. non-degradative ubiquitination to TRiC regulation unclear\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key open questions include the full scope of the di-Glu degron proteome, the structural basis for DCAF12's IAP/BIR-domain interaction, whether assembly quality control extends to additional multisubunit complexes beyond TRiC and MCM2-7, and whether DCAF12's ligase-dependent and ligase-independent (IAP-antagonist) functions are coordinated.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Systematic identification of all C-terminal di-Glu degron substrates not performed\",\n        \"No structure of DCAF12 bound to any IAP BIR domain\",\n        \"Relationship between CRL4 ligase activity and IAP-antagonist function unresolved\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 5, 7, 8]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4, 7]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [4, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1, 5, 7, 8]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 8]}\n    ],\n    \"complexes\": [\n      \"CRL4^DCAF12 (CUL4-RBX1-DDB1-DCAF12)\"\n    ],\n    \"partners\": [\n      \"DDB1\",\n      \"CUL4A\",\n      \"CCT5\",\n      \"MAGE-A3\",\n      \"MOV10\",\n      \"MCMBP\",\n      \"XIAP\",\n      \"cIAP1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}